*North American SynchroPhasor Initiative (NASPI)*

Performance and Standard Task Team (PSTT)

A Guide for PMU Installation, Commissioning and Maintenance

Part II

PMU Installation Procedures

*Last Updated: June 5, 2007*

*Task Team Leaders:*

Vahid Madani, PG&E

Damir Novosel, KEMA

*Task Force Contributors:*

Ken Martin, BPA -- *Task Force Leader*

Ritchie Carroll, TVA

Henry Huang, PNNL, CERTS

Virgilio Centeno, Virginia Tech

Damir Novosel, KEMA

Yi Hu, KEMA

Ray Hayes, AEP

Jerry Stenbakken, NIST

Tony Weekes, Manitoba Hydro

Revision History

+---------+------+-----------------------------------------------------+
| *       | **   | **Description**                                     |
| *Date** | Rev. |                                                     |
|         | \#** |                                                     |
+---------+------+-----------------------------------------------------+
| 0       | 1    | -   Development started.                            |
| 4/28/06 |      |                                                     |
+---------+------+-----------------------------------------------------+
| 7/31/06 | 2    | First draft completed                               |
+---------+------+-----------------------------------------------------+
| 4oct06  | 3    | Rev after review & edits (R. Hays, K. Martin)       |
+---------+------+-----------------------------------------------------+
| 30mar07 | 4    | Rev after review & edits (G. Stenbakken)            |
+---------+------+-----------------------------------------------------+
| 8May07  | 5    | Rev after review & edits (T. Weekes, H. Huang)      |
+---------+------+-----------------------------------------------------+
| 5June07 | 6    | Rev with 3 appendices, illustrations                |
+---------+------+-----------------------------------------------------+

Table of Contents

1\. Glossary of Terms [3](#glossary-of-terms)

2\. Preface [3](#preface)

3\. Overview [3](#overview)

4\. Pre-installation procedures [3](#pre-installation-procedures)

4.1 Installation design [3](#installation-design)

4.2 Pre-installation tests [3](#pre-installation-tests)

5\. During Installation [3](#during-installation)

6\. After Installation [3](#after-installation)

7\. Conclusions [3](#conclusions)

8\. References [3](#references)

9\. Appendix A: Responses Summary to Questionnaire on PMU Installation
and Maintenance
[3](#appendix-a-responses-summary-to-questionnaire-on-pmu-installation-and-maintenance)

9.1 Section 1: Introduction [3](#section-1-introduction)

9.2 Section 2: General Information [3](#section-2-general-information)

9.3 Section 3: PMU installation [3](#section-3-pmu-installation)

9.4 Section 4: PMU Commissioning [3](#section-4-pmu-commissioning)

9.5 Section 5. PMU Maintenance [3](#section-5.-pmu-maintenance)

9.6 Section 6: Other information [3](#section-6-other-information)

10\. Appendix B: Example of commissioning tests -- Manitoba Hydro
[3](#appendix-b-example-of-commissioning-tests-manitoba-hydro)

10.1 Section 1: Introduction [3](#section-1-introduction-1)

10.2 Steady-State Tests [3](#steady-state-tests)

10.3 Dynamic Tests [3](#dynamic-tests)

10.4 Conclusion: [3](#conclusion)

11\. Appendix C: Example of commissioning tests -- Bonneville Power
Administration
[3](#appendix-c-example-of-commissioning-tests-bonneville-power-administration)

11.1 Section 1: Introduction [3](#section-1-introduction-2)

11.2 In Service Readings for the Big Eddy 230 Phaser Measurement Unit
[3](#in-service-readings-for-the-big-eddy-230-phaser-measurement-unit)

List of Figures

**Figure 1. Typical PMU measurement process.
[3](#__RefHeading___Toc168844526)**

Figure 2. Recommended antenna mounting locations on pole or roof. Plot
of GPS satellite trajectories for 45° North latitude shows that best
coverage is to the south. [3](#__RefHeading___Toc168844527)

Figure 3. Example showing forms of IRIG-B comparing the un-modulated
(level shift) B000, 1 kHz modulated B120, and modified Manchester B200.
[3](#__RefHeading___Toc168844528)

Figure 4. When voltages and currents are brought into different relay
houses, it is necessary to use more than one PMU or a PMU that has
remote sensing units. A PMU needs each phase current; when sharing with
other devices, carry all 3 phases through to the return.
[3](#__RefHeading___Toc168844529)

Figure 5. Estimate positive sequence from individual readings if power
system is reasonably well phase balanced.
[3](#__RefHeading___Toc168844530)

Figure 6. Estimate real and reactive power from complex phasor values.
Be sure to use the phasor scaling values as well as PT/CT ratios.
[3](#__RefHeading___Toc168844531)

List of Tables

Table 1 Recommended cable lengths for signal transmission
[3](#__RefHeading___Toc168843701)

Table 2 Examples of required data rates using C37.118 data format &
protocol. [3](#__RefHeading___Toc168843702)

Table 3 Summary of design considerations for PMU installation
[3](#__RefHeading___Toc168843703)

Table 4 List of Responding Companies [3](#__RefHeading___Toc168843704)

# Glossary of Terms

**BPA/PDCStream** -- An extension of IEEE 1344, widely used by the BPA
PDC and human-machine interface software on the West Coast.

**GPS** -- Global Positioning System. A satellite based system for
providing position and time. The accuracy of GPS based clocks can be
better than 1 microsecond.

**IEEE 1344** \[4\] -- A highly efficient protocol for real time
SynchroPhasor data. Typically data is streamed in this format over
UDP/IP or across a serial link.

**IEEE C37.118** \[3\] -- Related to IEEE 1344, but adds much needed
capability. This protocol and its associated standard are intended to
replace IEEE 1344 and the BPA/PDCStream protocols. Typically data is
streamed in this format over UDP/IP or across a serial link.

**NERC** -- North American Electricity Reliability Corporation

**PDC** -- Phasor Data Concentrator. A logical unit that collects phasor
data, and discrete event data from PMU's and possibly from other PDC's,
and transmits data to other applications. PDC's may buffer data for a
short time period but do not store the data.

**PMU** -- Phasor Measurement Unit. A device that samples analog voltage
and current data in synchronism with a GPS-clock. The samples are used
to compute the corresponding phasors. Phasors are computed based on an
absolute time reference (UTC), typically derived from a built-in GPS
receiver.

**SuperPDC** -- The PDC which is implemented to collect all the phasors
of the Eastern Interconnection for the EIPP. It is physically located at
TVA.

**TCP/IP** -- TCP/IP is a low-level protocol for use mainly on Ethernet
or related networks. Most of the higher-level protocols use TCP/IP to
transport the data. TCP/IP provides a highly reliable connection over
unreliable networks, using checksums, congestion control, and automatic
resending of bad or missing data. TCP/IP requires time to handshake new
connections and will block if missing data is being resent.

**TVA** -- Tennessee Valley Authority

**UDP/IP** -- UDP/IP is a low-level IP protocol that provides
low-latency communication across Ethernet or related networks. UDP/IP
does not provide any error-control or resending of missing or bad data.
The Application will need to check data for correctness. UDP/IP however,
does not require time for handshaking and will not block, making it
ideal for real-time data communications.

**UTC** -- Coordinated Universal Time (initials order based on French).
UTC represents the time-of-day at the Earth\'s prime meridian (0°
longitude).

**CT** -- Current Transformer, used to couple an AC current from one
circuit to another.

**CCVT** -- Capacitively Coupled Voltage Transformer, used to transform
the voltage on a high voltage power line to a lower voltage that is
suitable for use inside a substation.

**PT** -- Potential Transformer, used to transform the high voltage on a
high voltage power line to a lower voltage that can be used with control
and measuring circuits; this type of transformer usually uses magnetic
coupling of wound circuits but can be a capacitively coupled unit.

**FO** -- Fiber Optic, a means of transmitting signal values using light
conducted on a fiber of optically conducting material.

**EIPP** -- Eastern Interconnect Phasor Project

**NASPI** -- North American SynchroPhasor Initiative

**PRTT** -- Performance Requirements Task Team

**PSTT** -- Performance and Standards Task Team

**CRC** -- Cyclic Redundancy Check, a code affixed to a block of data
that is computed from the data using a specific formula that can be used
to assure to a high degree of reliability that the data has not been
changed in any way since the CRC was computed.

**BPS** -- bits per seconds

**SONET** -- Synchronous Optical NETwork

# Preface

In this guide are recommendations for PMU installation. This guide is
based on general installation requirements for PMUs being manufactured
in 2007 and typical (sub) station configurations. Some anecdotal
information from utilities is included for informational purposes.
Manufacturers' recommendations and specifications, and standard
operating procedures of various utilities are ultimately the overriding
concern and will require the installers to write their own procedures. A
PSTT survey on PMU installation and maintenance shows different
situations at specific utilities and substations. The summary of that
survey can be found in Appendix I as well as in \[6\]. This guide should
only be considered as a starting point, and will be expanded and
modified from time to time based on user feedback.

# Overview

PMU installation requires access to signals to be measured, a timing
signal to synchronize the measurement, data communications to send the
measurement, as well as a power supply. Each of these items is discussed
in the pre-installation procedures below. A PMU primarily monitors AC
voltage and current signals and estimates a phasor equivalent based on a
time signal. A typical PMU uses an A/D converter to sample the three
single-phase AC waveforms of a three-phase signal. It estimates a phasor
equivalent for each single-phase AC signal, using the time reference to
establish the phase. These estimates are usually combined to obtain a
positive sequence equivalent that is recorded or reported. Single phase
monitoring and reporting is a valid option and preferred for some
applications (Figure 1).

![](media/image1.png){width="4.999305555555556in"
height="3.7493055555555554in"}

[]{#__RefHeading___Toc168844526 .anchor}Figure 1. Typical PMU
measurement process.

A PMU will typically monitor several three-phase voltages and currents.
Data can be recorded locally, sent to a remote location in real time, or
both. In this document it is assumed the users will be sending the data
to a remote location in real-time whether it is locally recorded or not.
If data are only recorded locally, skip the sections concerned with
communications. A PMU needs access to a communication system that can
transmit data at the PMU reporting rate and one that matches the format
and interface. These requirements are detailed below.

In some cases the PMU will have status inputs (Boolean 1 or 0) or other
measured value ("analog") inputs. Access to these signals will depend on
the situation, but need to be considered at the planning stage.

# Pre-installation procedures 

## Installation design

In most cases, a PMU installation is considered a permanent installation
and requires a complete design. Each utility has different procedures
for authorizing projects, designing installations, and carrying out
construction. Below are only supplementary guidelines to help scoping a
project and proceeding with the design.

PMUs need access to signals, time, data communications, and power.
Generally power comes from an AC or DC source that is relatively easy to
route anywhere. Communication ultimately goes out through some kind of
terminal system within the (sub)station which is usually easy to access
throughout the substation. Access to time and measured analog signals is
usually the most difficult to design, so these issues will be considered
first.

[Timing input]{.underline}

Many PMUs input time from GPS directly, which requires an antenna open
to GPS signals and a cable to the PMU within signal limitations.
Antennas ideally have a clear sky view (free from obstructions) above a
15 degree elevation. In most cases this is difficult to achieve, and
compromise factors need to be followed.

![](media/image2.png){width="3.4027777777777777in"
height="2.8916666666666666in"}
![](media/image3.png){width="3.8493055555555555in"
height="2.8868055555555556in"}

[]{#__RefHeading___Toc168844527 .anchor}Figure 2. Recommended antenna
mounting locations on pole or roof. Plot of GPS satellite trajectories
for 45° North latitude shows that best coverage is to the south.

Most of the signals will come from the south (in the Northern
hemisphere) from the horizon to about 15 degrees north of vertical
(Figure 2). Small obstructions more that 15" away from the antenna
should not cause a problem, but a large flat obstruction within a few
hundred meters could act as a reflector and cause multi-path problems.
The antenna should be mounted with a clear view to the south and as far
north as possible. Check around the mounting location for
structures---such as a flat metal roof---that is oriented so that it
could reflect a satellite signal to the antenna (keeping in mind
satellites will traverse most points in the sky). Also check for
obstructions that can block the signal, and high power signal sources
that could saturate the GPS input. Some GPS receivers have been operated
successfully with the antenna mounted inside a building, receiving
signals through the roof. In other situations mounting the antenna by a
southerly facing window has been successful. Many less than optimal
installations will experience some signal outage which degrades the
measurement, so the safest option is an open air sky-view installation.
The 1.5 GHz signal attenuates rapidly in a cable, and most vendors
recommend limiting cable runs to less than 150 ft. There are
alternatives for longer cable distances, such as high power antenna or
in-line amplifiers and low loss cable. In many substations, roof access
for cables is difficult, so a PMU should be located with this in mind.
For an externally mounted antenna, it is advisable to incorporate a
lightning arrestor into the design.

Some PMUs input time from a local source, such as a GPS receiver, using
a local signal type such as IRIG-B \[5\], 1 PPS, Have-Quick, IEEE 1588,
or something similar. Some of these signals degrade rapidly in a cable,
and all signals are delayed in cables, so excessive cable runs should be
avoided. When using this type of PMU, consult the vendor as to what
signals they require and whether the delays are compensated. Use a
signal source that will provide the required signals at the accuracy at
the PMU required for meeting timing requirements. For example, IRIG-B
may be specified and can be used in any of its modulated forms, but the
DC level-shift or the Modified-Manchester coding forms will allow the
highest accuracy.

![](media/image4.wmf){width="5.118055555555555in"
height="3.1354166666666665in"}

[]{#__RefHeading___Toc168844528 .anchor}Figure 3. Example showing forms
of IRIG-B comparing the un-modulated (level shift) B000, 1 kHz modulated
B120, and modified Manchester B200.

[Voltage & current input]{.underline}

Most PMUs convert voltage and current signals by sampling them with an
A/D converter. This requires an installation that has access to these
signals. In many substations, these signals are brought only to certain
buildings or cabinets, not all to a single location. In these cases it
is probably easier to install a PMU or PMU input unit where the signals
are found rather than extend the signal cables (Figure 4). Of course
installing multiple PMUs or input units will require installing multiple
synchronizing signals (and possibly multiple antennas) and some local
data distribution. This consideration may dictate the choice of PMU to
accommodate the station configuration. If possible, the PMU should be
installed with test access to the PT & CT inputs so test signals can be
injected for performance tests and calibration.

[]{#__RefHeading___Toc168844529 .anchor}Figure 4. When voltages and
currents are brought into different relay houses, it is necessary to use
more than one PMU or a PMU that has remote sensing units. A PMU needs
each phase current; when sharing with other devices, carry all 3 phases
through to the return.

Good measurements require consideration of the signal. The measurement
speed has to be fast enough to capture required frequency contents. The
range needs to be high enough to capture required maximums and low
enough for resolution. The PMU device should have adequate sample rates
and filtering for accurate signal representation. See the PSTT testing
guide for those considerations \[1\]. The PMU will specify the maximum
input range and resolution. Power system voltages rarely deviate more
than 10%, so the input should be set so the voltage input is 50-75% of
the maximum allowed. This gives some overhead for large swings, but good
resolution for nominal input. Currents will operate over a much larger
range. Fault recording and relaying requires a scale that will
accommodate very high currents; phasor measurements are concerned with
normal operational and system swing currents which range from somewhat
over nominal to light load (10% of nominal). Setting the maximum at
about 2X nominal will give good measurements at light load and normally
cover swings. However, it may be considered more important to capture
all swings and overloads at the expense of lighter loads. Sometimes the
PMU is a part of another device, such as a relay or DFR and the
calibration will be dictated by another requirement. This is a user
consideration where the user needs to be aware of the tradeoffs.

The PMU will also derive frequency from one of the AC input signals.
These are fully user selectable in some PMUs and fixed in others. Some
PMUs will allow selecting a backup channel when the primary one has a
low signal. To assure a good frequency measurement, it is best to select
a voltage input channel which has good signal strength, since these
don't vary as much as currents.

[Analog & digital input]{.underline}

Some PMUs allow connecting "analog" inputs. What this refers to is a
non-sinusoidal signal that represents some other kinds of measurement,
such as a MW transducer, transformer temperature, or stability control
setting signal. This signal value will be reported along with phasor
values in the time synchronized data packet, which opens up the use of
phasor data for many real-time and analysis applications. Generally
these data signals are easier to route than high-current CT circuits,
but they need to be considered. All PMUs should allow digital "status"
inputs. These are Boolean 0 or 1, and are represented as a single bit in
a digital word. Access to these signals is usually not difficult, but
again need consideration.

[Power input]{.underline}

Since PMUs need to operate continuously, and particularly without
interruption during disturbances, they should run on station DC power.
Be sure the PMU will run on whatever uninterruptible power source is
available at the station, such as 125 VDC.

[Communications]{.underline}

The PMU will need communication access. Communications are usually the
most problematic part of phasor measurement systems, so it pays to
carefully plan the system and be sure all aspects are addressed. The
first part will be cabling from the PMU to some kind of communication
interface. Next will be the interface itself. Last, at the PMU end, is
the communication system. The overall system including the application
end (PDC or other devices) requires complete planning, but that is
beyond the scope of this document.

Cabling is required between the PMU and the communication interface
(modem, router, etc). Most cabling is small and rather easy to route and
install. The principal issues are interference and cable length.
Substations are notorious for high interfering signals, particularly
during a nearby fault. The best policy is to use fiber optic cable (FO)
for all signals that travel outside of a single rack (grounding unit).
However, practically speaking, a signal within a building can run in
metallic cable as long as the length does not exceed maximum specified
distances. If the signal is to run between buildings, it should be run
over FO cables. In some cases this requires signal converters at each
end, but many vendors have FO I/O built into their equipment.

Metallic cable can be selected to minimize the most likely sources of
interference. Coaxial cable has good electrostatic shielding but is
subject to electromagnetic interference, particularly where ground
differences can occur (conduction through the ground). Shielded twisted
pair (Cat5) has good rejection for both electrostatic and
electromagnetic interference, but all shielding has limitations. High
magnetic fields can penetrate most kinds of shielding, so are best
treated by avoidance. It is best to route cables with some thought as to
what is in close proximity. Also note that many substation cables are
large and heavy, so they may pinch a poorly routed communication cable
resulting in loss of shielding and transmission properties. Table 1
below summarizes the signal types, the recommended and practical length,
and some comments. Please refer to PSTT's "SynchroPhasor Accuracy
Characterization" document for more considerations regarding cable
selection \[8\].

[]{#__RefHeading___Toc168843701 .anchor}Table 1 Recommended cable
lengths for signal transmission

+------------+-------+----------------+-------------------------------+
| **Signal   | **    | **Recommend    | **Interference/comments**     |
| type**     | Cable | max length**   |                               |
|            | t     |                |                               |
|            | ype** |                |                               |
+------------+-------+----------------+-------------------------------+
| As         | Tw    | 15 m @ 20K BPS | Actual length depends on      |
| ynchronous | isted |                | cable & rate.                 |
| serial     | pairs |                |                               |
| (RS-232)   |       |                |                               |
+------------+-------+----------------+-------------------------------+
| V.35       | Tw    | 600 m @ 100K   | Standard well specified and   |
|            | isted | BPS            | followed. Widely used outside |
|            | pairs |                | of US.                        |
|            |       | 90 m @ 10M BPS |                               |
+------------+-------+----------------+-------------------------------+
| S          | Tw    | 1200 m @ 100K  | Bipolar low level signal has  |
| ynchronous | isted | BPS            | good transmission             |
| serial     | pairs |                | characteristics               |
| (RS-422)   |       |                |                               |
+------------+-------+----------------+-------------------------------+
| Ethernet   | Co-ax |                | Good static shielding, use    |
| thin-net   |       |                | tri-ax where there are        |
|            |       |                | grounding issues              |
+------------+-------+----------------+-------------------------------+
| Ethernet   | Cat4  | 100 m          | Good shielding, move up to    |
| 10BaseT    |       |                | Cat5 for better signal        |
+------------+-------+----------------+-------------------------------+
| Ethernet   | Cat5  | 150 m          | Good shielding, use           |
| 1          |       |                | ruggedized version for better |
| 0/100BaseT |       |                | mechanical protection \*\*    |
+------------+-------+----------------+-------------------------------+
| Ethernet   | FO    | 2 km           | Best for interference         |
| 100BaseFX  |       |                | rejection & avoiding          |
|            |       |                | grounding problems            |
+------------+-------+----------------+-------------------------------+

\*\* Std CAT5 is Unshielded Twisted Pair (UTP). This should be Shielded
Twisted Pair (STP)

In addition to the physical installation summarized above, the
communication types need to match in type and rates. This is an
extensive area and will not be detailed here. The basic consideration is
the PMU itself and data rates required by the measurement system. The
PMU must be chosen so that it will output measurements at the rate
required by the measurement system. If the system runs at 30 samples per
second, the PMU needs to measure and output data at 30 samples per
second.

PMUs generally will have asynchronous serial (RS-232) or Ethernet
communications. Both will handle data at the rate and block size used in
most measurement systems. An interface device between the PMU and the
communication system is required. This area is not really clear since
vendors have used terminology loosely to describe their products.
Generally, a modem translates between a digital data system and an
analog communication system, and a CSU/DSU or router or bridge
translates between a digital data system and a digital communication
system. In either case, the PMU output is a digital data type and needs
one of these devices to interface to the communication system. The
important points are the appropriate sides of the interface have to
match the PMU and communication system, and must handle the required
data rate. If the PMU output is asynchronous serial, the interface must
handle asynchronous serial at the given rate.

[]{#__RefHeading___Toc168843702 .anchor}Table 2 Examples of required
data rates using C37.118 data format & protocol.

  ----------------------- ----------------------- -----------------------
  **30 frames/sec**       **All Integer format**  **All floating point
                                                  format**

  5 phasors, no           1260 bytes/sec          1980 bytes/sec
  analog/digital                                  

  10 phasors, no          1860 bytes/sec          3180 bytes/sec
  analog/digital                                  

  5 phasors, 2 analog/ 1  1440 bytes/sec          2280 bytes/sec
  digital                                         

  10 phasors, 2 analog/ 1 2040 bytes/sec          3480 bytes/sec
  digital                                         
  ----------------------- ----------------------- -----------------------

Notes:

-   Asynchronous serial requires 10 bits/byte, so required BPS rates are
    10X the above figures.

-   UDP/IP over Ethernet has a fixed size overhead of 54 bytes per
    packet, so actual required rate is higher than the requirement
    above. It ranges from 23,040 BPS for phasor/integer to 41,120 BPS
    for the 10 phasor-2 analog-1 digital/floating point shown above.

-   Since data is sent continuously at the rates shown in the table, the
    communication channel must have a capacity at least that large and
    should be at least 10% higher than the required data rate to
    accommodate error correction and short dropouts. The PMU port speed
    will likewise have to be equal or higher than the actual data rate.
    In many cases this requires high serial data rates, such as 38.4 or
    57.6 KBPS.

Generally speaking, asynchronous serial ports interface better with
analog modems than digital type interfaces. Analog modems are also easy
to interface with analog communications. The problems with analog modems
include limited bandwidth and data loss due to communication impairment.
Also, as digital communication becomes more prevalent, there is
decreasing availability and support for this equipment.

PMU communications by Ethernet match directly with digital systems and
interface well with digital communications, such as SONET. Ethernet
based digital systems are well developed and supported, so building
these systems is generally very straightforward. Care needs to be
exercised when connecting the local Ethernet system through a digital
communication system (e.g., SONET), usually called the WAN connection.
The WAN needs to support the minimum data rate with some room for
overhead and the interface needs to have sufficient buffering to match
WAN & Ethernet speed differences. Most of these systems currently use
Internet Protocol (IP) for data communication. Building and managing
these systems is centered on setting up IP hosts, subnets, and routing.

[Summary]{.underline}

The following table summarizes basic design considerations somewhat in
the order of importance. Since any factor can impact the whole project,
it is important to scope out the whole project before deciding on
equipment and making the designs. These are only the installation
considerations. For the overall project consideration, spare parts,
training, overall cost, and company policies are also important. Use
this installation information while keeping the overall project in mind.

[]{#__RefHeading___Toc168843703 .anchor}Table 3 Summary of design
considerations for PMU installation

  ------------------ --------------------------- -------------------------
  **Question**       **Answers**                 **Alternate answer**

  How many phasor    How many voltages are       How many feeder currents
  inputs are needed? available or important? Are are needed for important
                     bus voltages available? If  power flow calculations?
                     only line voltages are      
                     available, it is advisable  
                     to use two or use one with  
                     a backup in case a line is  
                     out of service.             

  Are all measured   Yes. Choose a single PMU    No. Choose PMU type that
  signals at a       type that supports the      can be networked or
  single location?   number of signals.          install multiple PMUs
                                                 that will handle all
                                                 inputs at a single
                                                 location.

  Does PMU require   Yes. Choose location that   No. IRIG-B/1PPS signals
  direct GPS input?  will have access to antenna are generally easier to
                     (a single antenna can serve route, but check wiring
                     several receivers).         availability.

  Does the PMU       If system is digital and    
  output match the   PMU is RS232, be sure       
  communication      interface is available in   
  system interface?  type and speed              

  What type of       If FO, will it match PMU?   
  communications are If not FO, are distances    
  established within short enough for galvanic?  
  the substation?    Grounding problems?         

  DC power           Be sure PMU matches the DC  
  available?         voltage available.          

  Need to modify PMU Yes, choose PMU that allows 
  operating          changing settings remotely? 
  characteristics                                
  remotely?                                      

  Will the circuit   Yes, no problems.           No, choose a PMU with
  handle the PMU                                 lower burden, such as
  burden?                                        isolated instrumentation
                                                 CT or different circuit.

  Does the           Yes, be sure the PMU has    No, any PMU qualified in
  application have   settings that match or use  other respects will do.
  particular         alterable settings.         
  filtering needs?                               
  ------------------ --------------------------- -------------------------

## Pre-installation tests

The extent of pre-installation testing depends on utility policies and
resources. This can range from complete performance testing and a
mock-up of the entire communication system to no testing at all. At a
minimum, some quality assurance testing should be done to be sure units
work in the planned system and are reasonably in calibration. If the
host utility has relay test sets or an equivalent signal generator, it
is relatively easy to put signals into the PMU and check that the output
meets specifications for a few magnitude and phase angle checks. If not,
this could be done by a contractor.

Overall, a host utility should have a complete set of test data for each
PMU type they use. The utility could do their own tests, or have it done
at a test lab capable of doing the tests. PMUs sample and process data
digitally. Each type will have characteristics that differ from other
types, but will produce measurements the same as other PMUs of the same
type. It is not necessary to fully characterize each one that is
installed. Also, since the A/D inputs tend to be accurate and stay
accurate, it usually is not necessary to do a precision calibration on
each individual unit (but it doesn't hurt either). The PSTT PMU test
guide or an equivalent test procedure should be followed for PMU
characterization and calibration.

If the PMU is going to be installed in a rack that will be shipped to a
substation, the verification test should be done on the completed rack
to assure the PMU is working and the rack is wired correctly. Bringing
the test signals into the host system will confirm that the whole system
less the remote communications operates together. All the tests that can
be done in a shop where everything is at hand will save time in the long
run. It is very difficult to troubleshoot a system a hundred miles away
when all you have to go on is data that may not be coming in reliably.
Typically the biggest problem is data communications, so minimizing
other problems ahead of time is worth the effort.

A risk assessment is needed to investigate worst case problem scenarios
which may occur while commissioning the PMU installation. This risk
would include information from an equivalent to Transmission Services
with respect to power system conditions allowed during commissioning.

Cyber security issues have to be resolved beforehand with information
services. Each utility will have its own recommendations, but the use of
a VPN form of communication not connected to the internal LAN is one
option to provide isolation and security. Communication links should be
in place prior to the day of commissioning the PMU.

# During Installation 

Installation is usually done by specialized crews with participation
from: Information Services, Plant Engineering, Protection Maintenance,
Communication Engineering, Commissioning, and Transmission Services. The
project manager can help coordinate these groups with a few meetings to
ensure questions are answered in all areas beforehand. Scheduling the
project is one of the biggest challenges especially since the priority
of the work is often low.

The project manager should be aware of when the commissioning is to be
done and be on hand for any questions (preferably with some wiring
drawings nearby and verbal communication to the PDC site).

# After Installation 

Depending on the utility, the measurement system user may or may not be
involved in the checkout and final calibration. If not, the
checkout/calibration data should be supplied to the user who will
confirm full system checkout. It is important to assure measurement
continuity from instrumentation to the end application.

The checkout at this point is to confirm operation on actual system
signals. Full calibration and characterization of the PMU and
measurement system should be done in a lab environment where the input
values can be precisely controlled. If the PMU installation is equipped
with a complete set of test jacks, the inputs can be accurately
measured, but since the real system is constantly changing, it is
difficult to achieve precision. Test jacks can be used for injection of
calibration signals which will be useful for periodic maintenance; this
is covered in the PSTT's "A Guide for PMU Installation, Commissioning
and Maintenance: Part III -- PMU Maintenance Procedures".

The principal points covered here are:

-   Is the measured quantity the correct one?

-   Are the values reasonably close to correct?

-   Are the measured values in reasonable agreement with other
    measurements?

-   Is the phasing relative to other local signals correct?

-   Is the signal phasing in agreement with other PMUs?

-   Is the PMU locking to the synchronizing signal and staying locked?

-   Are the communications performing well?

[Correctness of measured value]{.underline}

The most reliable method of checking the measured values is comparison
with the input. This is easiest to do if the PMU has a local readout or
tool that provides a local readout. Measure the input V & I with a
calibrated meter. The positive sequence phasor magnitude is
approximately the average RMS of all three phases (Figure 5). Be sure
you are measuring at a time that there are not huge value swings. Read
all 3 phases with an RMS meter and note the measured phasor value in
quick succession. Average the three readings and compare that with the
PMU measurement. For voltages, these should be within 2% and currents
within 5%. If the currents are very steady and midrange, the comparison
should also be within 2%. If phase imbalance is significant (\> 5%), it
is advisable to use phase angle as well as magnitude readings to come up
with the estimated value, since this also affects the positive sequence
equivalent.

![](media/image5.wmf){width="4.995833333333334in"
height="3.7368055555555557in"}

[]{#__RefHeading___Toc168844530 .anchor}Figure 5. Estimate positive
sequence from individual readings if power system is reasonably well
phase balanced.

[Comparison with other measured values]{.underline}

Checking input with measured value assures the wiring is correct and the
PMU channels are working. It does not assure the input is actually from
the line or bus that is supposed to be measured. Short of tracing wiring
from the PT or CT device, the best way to check this is comparison with
existing measurements. Compare with panel meters and transducer
measurements such as through the SCADA system. These often don't agree
very closely, so don't be alarmed. Most panel meters and transducers are
based on analog technology and are not very accurate at low levels.
Voltage is fairly constant at a median value so it is easy to get a good
comparison. Currents vary greatly, and are often low, so it may be
difficult to get a good reading. The important thing is that with proper
scaling the voltage should be within a few percent and the current
should agree in direction and generally in magnitude.

Issues with using these measurements include those on single phase
voltage or current and only power measurements. Use single phase
metering just as with 3 phase without averaging; just be aware that it
can be further off than you would normally expect. If there are only
power measurements, you can either combine the phasor current with the
appropriate bus voltage and compare power, or divide the power
measurement by (1.732 \* voltage) to determine the current. Current in
phase with voltage (\< +/- 90 degrees) is considered current out of the
bus and combined with bus voltage will compute as power out of the bus
(Figure 6).

Don't expect the readings to agree closely, even if the PMU is carefully
calibrated. The error is often (usually?) in the SCADA measurements.
Many SCADA voltage measurements use only single phase transducers. It is
common to have 2-3% imbalance in phases which show up as a 10-15 kV
difference in measurements. Transducers that are calibrated infrequently
can further increase error. Modern digital displays show as many digits
as the user wants to see, whether they mean anything or not. Displays
frequently use 4-5 digits even though the measurement accuracy is
usually limited to 2-3. Consequently the user sees measurement errors
where there are none. Phasor measurements are often suspected because
they disagree with SCADA, and SCADA is the reference everything is
compared to. It pays to check the phasor measurement well enough to be
sure it is defensible if there are perceived differences.

![](media/image6.wmf){width="4.995833333333334in"
height="3.7368055555555557in"}

[]{#__RefHeading___Toc168844531 .anchor}Figure 6. Estimate real and
reactive power from complex phasor values. Be sure to use the phasor
scaling values as well as PT/CT ratios.

Another valuable comparison is the System State Estimation (SE) value
for the measured phasors. SE can provide accurate voltage and current
amplitude, and phase angle relative to the reference (swing) bus.
Comparing this with another certified PMU can provide a good check of
measured phase angle. Be sure the comparisons are made at the same time
since loading and angles constantly change.

[Phasing of local signals]{.underline}

Once the phasor measurements can be confirmed as correct and defensible,
the phasing of the signals relative to each other should be checked.
A-phase for each signal must be correctly wired as A-phase for the
conversion. If not, signals will be displaced +/- 120 degrees from what
they should be. Current inputs should be oriented so that current is
approximately in phase with voltage when power is flowing out of the
bus. CT circuits can be easily reversed, so be sure to check this. (Some
utilities use the opposite orientation, so check with your utility
design standards.) Generally current will be within ±20 degrees of the
voltage (power leaving the bus) or 160 to -160 degrees of the voltage
(power entering the bus). Your utility standard may be the opposite, so
check this before reversing the CT wiring. The exceptions are if the
current is feeding a reactive device or an open line. If feeding a
capacitive device or open line it should be about 90 degrees leading and
a reactor about 90 degrees lagging. However, if feeding a synchronous
condenser the angle can be either way. In any case, be sure the current
directions are properly oriented relative to the voltage. It is usually
instructive to convert the phasor values into MW and MVAR and compare
with other measurements. At low values, various measurement systems may
differ significantly, but anything near full scale should be within a
few percent. MVAR is typically difficult to confirm, since it is usually
very small in relation to the feeder MVA. Again, comparisons with the
System State Estimator are another good way to check the measurement.

[System signal phasing]{.underline}

This is the topic of a whole paper written by the PSTT \[7\]. Generally
within a single utility, A-phase is well defined and the same at all
substations. The easiest way to determine that A-phase at a new PMU
installation agrees with other installations, is to compare the phase
angle with the nearest installed PMU. It the two stations are adjacent
to each other, the angle between them can be approximately calculated
by:

> ![](media/image7.wmf){width="1.0in" height="0.3888888888888889in"}

where *P* = power flow on the line, *X* = line reactance, and *V*~1~ and
*V*~2~ are the bus voltages. Line resistance and line charging are
neglected. Power always flows from a leading angle to a lagging one. The
measured angle should be reasonably close to the value calculated from
the power flow above. If the stations are not adjacent, or the
parameters are not well known, this heuristic approach can be used:
power flows from buses with leading angles to those with lagging angles.
If there is little power flow, the distance is short, or the impedance
is low, the angle will be small. Higher voltage systems have lower
impedance. Multiple lines or a meshed grid has lower impedance. Note the
power flow in the area between the stations being compared. If it is
notably flowing from one to the other, the angle definitely should match
in polarity. If the stations are fairly close, say within 200 miles,
expect an angle of 30 degrees or less. If they are more distant, it
could be higher, even over 90 degrees in a meshed grid. If the power
flow between stations is not clearly one direction or the other, the
angle could go either way but the total should be smaller, perhaps in
the area of 15 degrees. Ultimately, without a number of accurate power
flow measurements, it is difficult check the accuracy of phase angle
measurements. However, the main objective here is to confirm measurement
phasing. A phase selection error results in a 120 degree phase shift,
which should be distinguishable from the angles estimated by power flow.
Note that it is not possible to determine inter-station phasing errors
using only one station. Phase angle measurements are relative to
absolute time and do not indicate relative bus measurements. Also note
that comparing phase differences across Y-∆ and phase shifting
transformers as well as series capacitors can produce results that make
phase checking difficult to determine. Generally a 120 degree error is
big enough to be obvious, but pay attention to all these factors.
Loading at the time of comparison will affect the phase angles seen so a
few tests throughout the day at different loadings are needed to confirm
the phase angles seen are within a reasonable range. Large errors of 30
degrees can usually be detected if the PMU is assumed to be connected
for line-to-neutral measurements but is actually line-to-line (or
vice-versa). Large errors of 120 degrees can also be detected if the
rotation of the sequences for phase A, B and C, is in a different order
than expected. With these large errors removed, comparison to SCADA load
flows can be expected to be within 5 degrees.

[Time synchronization]{.underline}

Most PMUs have direct indication of time synchronization. This should
indicate time synchronization as soon as the power is on and time
synchronization is supplied. Since this will be vendor specific, only
general observations will be offered here.

If time synchronization is supplied directly from GPS with a built-in
decoder, the system should show lock with at least 4 satellites at all
times. If fewer than that are indicated after initial lock, the antenna
may be impeded or there may be a source of interference. An over-length
cable run or damaged cable can also lead to low signal and tracking
fewer than optimum satellites. Initial lock may take a while, up to 30
minutes, but re-lock after a reset or power cycle should only take a few
minutes. Lock will be indicated in the data. This should be observed
closely the first few days to be sure the PMU maintains continuous lock.
If it does not, again check the antenna, cable, and overall
installation.

If time synchronization is supplied by another system through a signal,
such as IRIG-B \[5\], the PMU should indicate lock shortly after the
system is powered on provided the clock sends quality extension bits as
specified in IEEE 1344 \[4\] or C37.118 \[3\]. The PMU should provide an
indication that it is locked to the signal. Monitor this closely for the
first few days to be sure it maintains continuous lock. Some time codes
include a quality indicator generated by the signal source, and this may
be monitored by the PMU; if so, check this as well during the break-in
period. A local signal source could be set to local time (daylight or
not) as well as UTC. By standard, all phasor measurements are provided
in UTC time, so it may be necessary to adjust settings in the time
source or the PMU. Check vendor specifications for these issues.

[Communications operation]{.underline}

Communications from the PMU to the data concentrator is a critical link
and often the most troublesome. Initial checkout details depend on the
particular system. A few general observations are offered here.

Data are sent at the selected reporting rate from the PMU in packets
that are precisely timetagged and terminated with a CRC or checksum. In
many cases, the communication medium provides its own packetizing with a
check word. The receiving device (e.g. PDC) should use the check word to
detect corrupted data and timetags to keep track of missing data. This
information is essential for initial system checkout as well as ongoing
maintenance and repair.

After installation, corrupt and missing data should be monitored closely
for a few days. A good communication system should not lose more than 3
packets/hour at a data rate of 30 samples per second. At the receiving
end, it is not possible to differentiate between data that has been lost
in communications and data that was never sent. Pre-installation testing
should include enough monitoring to prove that the PMU outputs data
reliably (or does not!). Here it is assumed missing data indicates
losses in the communication system. Losses greater than 5% are seriously
underperforming and need to be fixed. The amount of tolerable loss
depends on the application and user. Real-time applications that need to
operate within the span of a few packets need very high reliability. If
the user is only using the data for trending or translation to SCADA
rated, a 5% loss may be tolerable, depending on how it is distributed.

Patterns of data loss indicate different problems depending on the type
of communication. RS-232 serial systems using analog or digital
communications will have a few check word errors and a few lost packets
per hour with a normal communication system. It may show increased
loss---particularly longer periods of outage---at certain times of day
if affected by fading (temperature related). Occasional to frequent
outage blocks can indicate communication system synchronization problems
or modem re-synchronization due to low signal levels. Any more than a
few lost samples/hour usually indicates a communication problem that can
be resolved. Experience has shown this type of system with solid and
well maintained communications can run for weeks without a single lost
packet.

Network based systems over analog communications will behave somewhat
like the RS232 mentioned above. Network over digital communications can
be divided into connected types like TCP/IP and non-connected like
UDP/IP. TCP provides packet ordering and re-transmission in the case of
missing or corrupted packets. With a good communication system, data
will be delayed occasionally, but otherwise there will be no data loss
apparent to the user. With a degraded or overloaded system, data delay
may become significant enough that TCP cannot recover lost packets and
there will be longer outages while the system holds data waiting for
recovery, and then has to re-synchronize the data stream.

With UDP, data is sent to a destination, but there is no built-in
ordering or recovery. Sometimes ordering and re-transmission can be
built into the application. UDP is used commonly with phasor measurement
systems since it is fast, un-delayed, and simple. A small amount of lost
data is tolerable and preferable over delayed data in many applications.
With a good communication system, data will rarely be delayed and data
loss will be less than 1 packet/hour (in practical experience, these
systems have be observed to run weeks without any data loss). Occasional
packet loss is expected. If a general purpose network is being used,
there may be greater loss during periods of heavy use. Router or switch
mis-configuration problems can cause unresolved collisions resulting in
high loss. Loss greater than 3 packets/hour warrants investigation,
particularly during installation time, since that indicates a
configuration error.

Once in service, the user will have to determine by experience what is
indicated by different patterns of data loss. A complete outage can
indicate PMU failure or communication system failure. Varying degrees of
loss can indicate configuration errors, overloads, synchronization
issues, and so on. Being able to provide guidance to maintenance staff
speeds repair and helps in maintaining the system in top operating
condition.

[Record keeping]{.underline}

A permanent record of installation details and initial tests is
important. The installation will normally have formal drawings that
include wiring and physical layout, but not necessarily details of
scaling, ratios, and settings. A clear record of settings is essential
for checkout, verification, and ongoing maintenance. This record should
include all PT/CT scaling, PMU calibration factors, communication
settings, triggers, limits, and recording parameters. It should be used
and confirmed during the checkout outlined above. Additional information
like cable type and length, CT/PT/CCVT details, etc. can help with other
efforts ongoing in the NASPI. The record of initial tests can be used as
a baseline during ongoing maintenance and provides a baseline for
problem resolution. In the past, installation test records have been
used on several occasions to see if a particular issue was actually
tested initially or was the result of a change in the system, or some
kind of component failure.

# Conclusions

This PMU installation guide has been produced by the PSTT, first under
the EIPP project and continuing under the NASPI. It is intended to
supplement vendor instructions and utility company guidelines for the
installation of PMUs. Details for installation depend on the actual
equipment being used. Use this as an overview or as an outline for
developing your own company guidelines and policies. Please report any
omissions or discrepancies as well as further suggestions to the PSTT.
This is intended to be a "living document", subject to continuous
update.

# References 

\[1\] *"PMU System Testing and Calibration Guide"*, Performance and
Standards Task Team (PSTT) of the North American SynchroPhasor
Initiative, 2007.

\[2\] *"Implementation of Virtual Bus Angle Reference"*, Performance
Requirements Task Team (PRTT), Eastern Interconnection Phasor Project,
January 2007.

\[3\] *"IEEE C37.118-2005, IEEE Standard for Synchrophasors for Power
Systems"*. Supersedes and replaces IEEE1344, 2005.

\[4\] *"IEEE 1344-1995 Standard for Synchrophasors for Power Systems"*.
Superseded by C 37.118 above, 1995.

\[5\] *"IRIG Standard 2004 -- IRIG Serial Time Code Formats"*, Timing
Committee, Telecommunications and Timing Group, Range Commanders
Council, US Army White Sands Missile Range, NM 88002-5110, September
2004.

\[6\] *"Responses Summary to Questionnaire on PMU Installation and
Maintenance"*, Performance Requirements Task Team (PRTT), Eastern
Interconnection Phasor Project. May 2006.

\[7\] *"Performance Requirements: Phase Angle Installation Issues"*,
Performance Requirements Task Team (PRTT), Eastern Interconnection
Phasor Project. March 2007.

\[8\] "SynchroPhasor Accuracy Characterization", Performance and
Standards Task Team (PSTT) of the North American SynchroPhasor
Initiative, 2007.

# Appendix A: Responses Summary to Questionnaire on PMU Installation and Maintenance

## Section 1: Introduction

The Performance and Standards Task Team (PSTT) of the Eastern
Interconnection Phasor Project (EIPP) in the process of creating a
guideline for installation and maintenance of phasor measurement units
(PMUs) sent a survey to PMU users participating in the EIPP. The intent
of the survey was to collect data to reduce some of the possible
installation problems, provide some reference for PMU maintenance, and
create a general and practical guideline to future users.

Where applicable multiple choice answers were provided but users were
encouraged to add any comments, explanations or questions. It is worth
mentioning that some responses were received from companies that do not
posses PMUs but are planning to install them and/or use them in the near
future.

The following sections of this document provide a summary of the
responses of the seventeen companies that answer the survey. The
comments received from the different companies for some of the question
are also listed. After reviewing the responses to the questioner the
PSTT realized the limitations of the multiple choice options and
recommends that numerical answer be requested in future questioners.

[]{#__RefHeading___Toc168843704 .anchor}Table 4 List of Responding
Companies

  ----------------------------------- -----------------------------------
  **Company**                         **Contact**

                                      

  American Electric Power             Sanjoy K Sarawgi

  Alberta Electric System Operator    Darren McCrank

  Ameren                              Rajesh Pudhota

  Arizona Public Service Co.          Douglas Selin

  BC Hydro                            Harry Lee

  Bonneville Power Administration     Ken Martin

  Entergy                             Floyd Galvan

  Florida Power and Light             Don Mcinnis

  Hydro Quebec                        Danielle Mcnabb

  Michigan Electric Transmission      Paul Myrda
  Company                             

  MidAmerican                         Mark Albright

  New York ISO                        Dean Ellis

  New York Power Authority            Bruce Fardanesh

  PG&E                                Fred Henderson

  PJM                                 Jon Ponder

  Southern Company                    Lee Taylor

  Tennessee Valley Authority          Ory Shannon
  ----------------------------------- -----------------------------------

## Section 2: General Information

2.1 How many PMUs does your company currently own?

![](media/image8.wmf){width="5.999305555555556in"
height="2.535416666666667in"}

2.2 What are the models of the PMUs your company currently owns?

![](media/image9.wmf){width="5.992361111111111in"
height="2.529861111111111in"}

2.3 How many PMUs is your company planning to install over the next
year?

![](media/image10.wmf){width="5.999305555555556in"
height="2.5194444444444444in"}

2.4 What applications are you using, or do you plan to use, the PMUs
for?

![](media/image11.wmf){width="5.995138888888889in"
height="3.2736111111111112in"}

Other:

a.  Detection of geomagnetic activity. High accuracy frequency
    monitoring. Accumulated time error monitoring (Hydro Quebec).

b.  Potential subsynchronous resonance condition near a critical power
    plan but suspect that the relay sample rates, processing, and memory
    are inadequate (MidAmerican)

c.  Monitoring the units (Ameren).

2.5 How many years since the first PMU was installed in your company?

![](media/image12.wmf){width="5.999305555555556in"
height="2.5243055555555554in"}

## Section 3: PMU installation

3.1 Is the installation manual coming with your PMU helpful?

![](media/image13.wmf){width="5.998611111111111in"
height="2.4611111111111112in"}

3.2 Were there existing CTs/PTs available for your PMU installation?

![](media/image14.wmf){width="5.99375in" height="2.4722222222222223in"}

3.3 What type of data networks available for your PMU installation?

![](media/image15.wmf){width="5.995833333333334in"
height="2.4472222222222224in"}

3.4 Are your data networks narrowband channels (voice channels) or
broadband channels?

![](media/image16.wmf){width="5.99375in" height="2.4506944444444443in"}

3.5 What time synchronizing signals are available for your PMU
installation?

![](media/image17.wmf){width="5.997222222222222in"
height="2.4506944444444443in"}

3.6 Does the engineer or technician installing the PMU have remote angle
information from the utility selected reference phasor?

![](media/image18.wmf){width="5.995833333333334in"
height="2.4472222222222224in"}

3.7 Does the engineer or technician installing the PMU have access to
real and reactive power flow information from a separate device?

![](media/image19.wmf){width="5.995833333333334in"
height="2.4472222222222224in"}

3.8 Does the engineer or technician installing the PMU have access to
phasor data concentrator (PDC) information?

![](media/image20.wmf){width="5.99375in" height="2.4506944444444443in"}

3.9 Does the engineer or technician installing the PMU have
communication with the control center that collects PMU information?

![](media/image21.wmf){width="5.995833333333334in"
height="2.4472222222222224in"}

3.10 Is it generally assumed that utilities can consistently identify
phases 'a', 'b', and 'c' voltage and current signals at their
substations?

![](media/image22.wmf){width="5.99375in" height="2.44375in"}

3.11 To your knowledge, is there any agreement among utilities on which
phase is called phase 'a'?

![](media/image23.wmf){width="5.998611111111111in"
height="2.446527777777778in"}

3.12 Do you know the phase 'a' convention of your neighboring utility
companies?

![](media/image24.wmf){width="5.997222222222222in"
height="2.4506944444444443in"}

3.13 How is the phase 'a' identified when you install your PMUs?

![](media/image25.wmf){width="5.99375in" height="2.457638888888889in"}

a.  Phase A is always identified within the substation. It is originally
    identified when hooking up with other substations, but by convention
    is the N. or S. or E. or W. bus in the stustaiton. That is, it is
    the bus on the same side relating to direction in every station, but
    I don\'t know which it is (BPA).

b.  By looking at the detailed protection wiring schematics of the
    substation where each PMU is installed (Hydro QB)

c.  From the prints, markings, and labels (NYPA).

d.  Phase ID\'s are labeled on substation structures and represented on
    3-line diagrams (TVA).

3.14 How long did it take you to complete the installation of one PMU?

![](media/image26.wmf){width="5.99375in" height="2.457638888888889in"}

3.15.a. What is the average cost of hardware, including PMU, for one
installation?

![](media/image27.wmf){width="5.997222222222222in"
height="2.457638888888889in"}

3.15.b. What is the average cost of labor for one PMU installation?

![](media/image28.wmf){width="5.995833333333334in"
height="2.4472222222222224in"}

3.15.c What is the average Total cost for one PMU installation?

![](media/image29.wmf){width="5.997222222222222in"
height="2.4506944444444443in"}

## Section 4: PMU Commissioning 

4.1 What test did you perform before commissioning the installed PMUs?

![](media/image30.wmf){width="5.995833333333334in"
height="2.5840277777777776in"}

Other

a.  It varies depending on who does the installation (BPA).

b.  We plan to perform the above tests when the first single test PMU
    installation is completed (MidAmerican).

4.2 Do you check PMU accuracy on every unit? On random Measurement
samples, None?

![](media/image31.wmf){width="5.99375in" height="2.5729166666666665in"}

4.3 What else do you do to initially calibrate PMU measurements?

a.  Verify PT and CT ratios with System Protection (PG&E)

b.  We have no way to calibrating the unit as we have no other PMU to
    compare it with (PJM).

c.  Compare to SCADA (Alberta Electric)

d.  No calibration is done on the PMUs (AEP).

e.  Meter is calibrated by manufacturer and they deliver a calibrated
    meter (Entergy).

f.  Each unit is calibrated in the lab, all the settings are entered and
    tested except final PT/CT ratios, and the operation is confirmed.
    Calibration is done using accurate test instruments and meters
    calibrated against traceable standards (BPA).

g.  Each PMU has been tested for accuracy in lab before installation.
    Once installed, the measured voltage phase angle is checked to make
    sure that the phasing is correct (Hydro QB).

h.  Look at data from the state estimator in the EMS and local meters.

## Section 5. PMU Maintenance

5.1 Is there a maintenance manual coming with your PMU products? If yes,
is it helpful?

![](media/image32.wmf){width="5.999305555555556in"
height="3.0381944444444446in"}

5.2 What kind of maintenance is performed on your PMUs?

![](media/image33.wmf){width="5.997222222222222in"
height="2.3895833333333334in"}

Other:

a.  Cleaning fans. Replace backup batteries (Hydro QB)

b.  The Maintenance program has not been specified (MidAmerican).

c.  Meter is pulled and send back to manufacturer for calibration
    (Entergy).

d.  Not yet determined (METC).

e.  No online monitoring of PDC anyway (BC Hydro).

f.  Will do whatever is required. Maintenance is expected to be minimal
    (PJM).

g.  Maintenance is an on-line operation, and re-calibration and repair
    when there is an obvious problem or failure. We have no routine
    maintenance (BPA).

5.3 How often do you perform maintenance on your PMUs?

![](media/image34.wmf){width="5.993055555555555in"
height="3.0388888888888888in"}

5.4 What alarms do you have to alert you to problems?

![](media/image35.wmf){width="5.998611111111111in" height="3.05in"}

Other:

a.  Our PMUs are on-line all the time. Synchronication & outage problems
    are tracked and reported by the concentrator. Calibration problems
    must be reported by users. If reported, we will investigate and
    resolve the issue (BPA).

b.  Email indicating loss of communication (Alerta Electric SO).

c.  No planning on using alarms (PJM).

d.  There are other indications on the PDC but there are no alarms
    (PG&E).

e.  Alarm capability exist in PMUs but it is not used (AEP).

f.  Utility to talk to the PMU (NYPA)

5.5 Do you monitor the performance of your overall measurement system
other than just PMUs?

![](media/image36.wmf){width="5.999305555555556in"
height="3.046527777777778in"}

5.6 What is the average time from problem appearance to correction?

![](media/image37.wmf){width="5.995833333333334in" height="3.03125in"}

###  {#section .unnumbered}

## Section 6: Other information

6.1 Do you think an installation/commissioning /maintenance guide would
help your job?

![](media/image38.wmf){width="5.995833333333334in"
height="3.0493055555555557in"}

6.2 Did you have any other problems during PMU
installation/commissioning/ maintenance?

a.  The field needs to be educated in these new instruments. We plan on
    hosting a two day meter workshop for our field personnel. (ENTERGY)

b.  The biggest problems seem to be getting the data communications to
    work right with the PMU and data concentrator. This is when there is
    a mismatch, such as synchronous to asynchronous or network to
    channel. Standard interfacing is sometimes difficult to specify and
    install (BPA).

c.  Sometimes there is an issue with the GPS antenna where the cable is
    pinched or broken. In one case the antenna was close to a UHV line
    and induced voltage zapped it. Since then if there is any
    possibility of that, I have instructions for grounding during
    installation and hook-up (BPA).

d.  The biggest maintenance problem is getting people to notice sync or
    data promptly, and notify the right personnel to fix the problem. It
    is often difficult to diagnose the root cause from the symptom, so a
    lot of issues go un-resolved for a long time (BPA).

e.  Firmware did not comply to specifications (took about one year to
    correct, Hydro QB).

f.  Early hardware failure on one unit after installation (Hydro QB).

g.  Inability to get up to date communication front ends for the PMU.
    Slow upgrade of the vendor.

# Appendix B: Example of commissioning tests -- Manitoba Hydro

## Section 1: Introduction

> Manitoba Hydro performed field tests on its Dorsey PMU on March 9
> 2007. The results are shown here. The test set up used for the PMU
> Performance tests is shown in figure 1 below.
>
> ![](media/image39.jpeg){width="5.999305555555556in"
> height="2.66875in"}
>
> Figure B.1 -- Test Set up shown uses 1 PPS signal from GPS to
> synchronize Doble Test Set software and produce -90 positive sequence
> angle when the positive zero crossing of A-phase is aligned with this
> 1 PPS. At nominal frequency of 60 Hz this zero crossing does not
> change (nor does it change for exact integer off-nominal frequencies
> of 61 Hz or 59 Hz etc.)
>
> The connection tester software shown acted like a local PDC and was
> used to confirm correct expected magnitudes and angles. Final results
> were taken from the PDC located at TVA (Tennessee Valley Authority) in
> order to include all delays including any delays within the network.

## Steady-State Tests

> The results are for the MBHydro PMU located at the Dorsey station on
> their 230 KV voltage and the positive sequence angle is taken for
> various initial angles of Va.
>
> For Va = 0 degrees the pos sequence angle is -90.36782837 (expected
> -90 degrees according to the defined phasor in C37.118) as shown in
> Fig 2. The error is 0.36782837 degrees.
>
> Similarly for Va= 120 degrees the angle is +29.63899994 degrees
> (expected 30) and for Va=240 degrees the angle is 149.6264954 degrees
> (expected 150). A close up of the angle for Va=0 is shown in Fig 3.
>
> ![](media/image40.wmf){width="5.371527777777778in"
> height="3.685416666666667in"}
>
> Figure B.2 -- Phasor Outputs Positive Sequence Angle as Va is rotated
>
> ![](media/image41.wmf){width="5.99375in" height="4.113888888888889in"}
>
> Figure B.3 -- Phasor Output Angle Close up for Va=0 degrees
>
> ![](media/image42.wmf){width="5.99375in" height="4.113888888888889in"}
>
> Figure B.4 -- Phasor Output Magnitude Close up
>
> The voltage magnitude for the injected voltage of 69.3 V was expected
> to be 138.6 kV and was found to be a maximum of 138.617 or an error of
> 0.017kV.
>
> The maximum error in the vector for positive sequence is 138.617 kV
> and an angle of -90.37 degrees or 0.006486545700177 --
> 1.004450070277750j compared to an ideal = 0.00-1.00j or 138.6 kV and
> an angle of -90.0 degrees.
>
> This compares well to the C37.118 standard (note, the standard does
> not include errors in the field which are outside of PMU device
> itself - ie. these field result errors are what is termed full-scale
> tests that do not separate the time tagging error and the angle
> accuracy) which sets a maximum error on angle of 0.57 degrees and a
> voltage error of less than 1.0%.
>
> ![](media/image43.wmf){width="3.6527777777777777in"
> height="0.34652777777777777in"} = 0.007866282514468 or 0.8%
>
> This measurement can be averaged over the number of times the test was
> performed by:
>
> ![](media/image44.wmf){width="4.958333333333333in"
> height="0.4166666666666667in"}
>
> Here TVE based on the three measurements of positive sequence voltage
> and angle as in (ie. Va=0 deg., Va=120 deg., and Va=240 deg. from in
> Figure 2 and Figure 4) is 1/3(0.7866%+0.772300%+0.7866%) = 0.781852%
> or approx. 0.8%

## Dynamic Tests

> The same set up as in Figure 1 was used for dynamic tests but
> synchronizing the start of the test was more difficult. We attempted
> to record the GPS time in an effort to retrieve the data for the start
> of the step changes. By examining the frequency and magnitude test
> results we could see when the tests occurred but there time values did
> not exactly match our recorded GPS times. We were still able to align
> the tests and get valuable information shown below.
>
> ![](media/image45.wmf){width="5.995138888888889in"
> height="4.113888888888889in"}
>
> Figure B.5 -- Step Change in Magnitude on all three phases from 230 kV
> L-L nominal (66.4 V L-N injected) to 0kV (0V injected). The response
> time appears to be about 100 ms. The recorded GPS time of the test was
> 15:17:15 and the chart shows the test at 15:17:04 so it is not clear
> why the mismatch and there could be an additional delay before the
> signal begins to ramp down (inherent to network). Once the signal
> begins to ramp though we can definitely say the response time is 100
> ms. A positive step exhibited a similar response.
>
> ![](media/image46.wmf){width="5.99375in" height="4.113888888888889in"}
>
> Figure B.6 -- A step change if frequency on all 3 phases from 60 Hz to
> 59 Hz. It is evident that there is some overshoot initially and then a
> quickly damped oscillation to the final value of 59 Hz. The response
> time to get to with 99% of 59 Hz is about 100 ms.
>
> ![](media/image47.wmf){width="5.99375in" height="4.113888888888889in"}
>
> Figure B.7 -- Absolute Phase Angle in degrees is plotting while at 59
> Hz. The roll over can be seen to occur at exactly the same time
> xx:xx:x.232 seconds and the magnitude of the phase angle after each
> roll over is the same at 171.5686950684 degrees. This shows good
> accuracy of the PMU. Also the slope is 360 .235810526 degrees/second
> with an error of only 0.07%.

## Conclusion:

> The PMU installed is meets the criteria of C37.118 even with any extra
> delays inherent from network or field. The TVE is about 0.8% and the
> dynamic response appears to be within 100 ms. PT and CT error would
> add to the error shown here and has not been evaluated.

# Appendix C: Example of commissioning tests -- Bonneville Power Administration

## Section 1: Introduction

This commissioning test example is from a PMU installed at the Big Eddy
substation in Jan 1998. This was long before the standard C37.118 was
available, so there was no criteria for comparison. The focus of this
test was to establish that the PMU was properly installed, measured the
correct signals, and compared reasonably accurately with other
measurements.

## In Service Readings for the Big Eddy 230 Phaser Measurement Unit 

***All quantities are referenced to "A" phase Bus section #3 1V-0V.
Measurements made on 1/6/98 from 1 to 2:30 pm. Board Meters and board
meter racks where read on all lines, then Rack 67 was read for all
lines. After that Scada reading where entered. Due to the time lag,
magnitudes may be off some. The power house lines where fluctuating a
lot due to some generator control problems.***

  ------------------------------ -------------------------- --------------------------- ----------------------------- ------------------------- -------------------------- --------------------------- ----------------------------- --------------------------------- ---------------------------
                                 ***Rack 67***                                                                        ***[PTR /]{.underline}*** ***Board Meter Racks***                                                                                                

  ***[Quantity]{.underline}***   ***[Mag.]{.underline}***   ***[Angle]{.underline}***   ***[Primary]{.underline}***   ***[CTR]{.underline}***   ***[Mag.]{.underline}***   ***[Angle]{.underline}***   ***[Primary]{.underline}***   ***[BoardMeters]{.underline}***   ***[Scada]{.underline}***

                                                                                                                                                                                                                                                                       

  **Bus Sect. 3 VA**             69.3                       ref.                        240.1                         2000/1                    69.4                       ref.                        240.4                         240 kv                            240.2 kv

  **Bus Sect. 3 VB**             69.1                       -120                        239.4                                                   69.6                       -120                        241.1                                                           

  **Bus Sect. 3 VC**             69.0                       120                         239.0                                                   69.1                       120                         239.4                                                           

                                                                                                                                                                                                                                                                       

  **Bus Sect. 1 VA**             69.1                       ref.                        239.4                         2000/1                    69.6                       ref.                        241.1                         240 kv                            239.9 kv

  **Bus Sect. 1 VB**             69.0                       -120                        239.0                                                   69.7                       -121                        241.4                                                           

  **Bus Sect. 1 VC**             68.9                       120                         238.7                                                   69.5                       120                         240.8                                                           

                                                                                                                                                                                                                                                                       

  **Celilo #3 IA**               1.07                       48                          642                           3000/5                    1.06                       48                          636                           180 mw out                        177 mw out

  **Celilo #3 IB**               1.08                       -71                         648                                                     1.06                       -71                         636                           190 mv in                         196 mv in

  **Celilo #3 IC**               1.07                       167                         642                                                     1.05                       167                         630                           550 amps                          634 amps

                                                                                                                                                                                                                                                                       

  **Celilo #4 IA**               1.19                       48                          714                           3000/5                    1.20                       47                          720                           200 mw out                        197 mw out

  **Celilo #4 IB**               1.19                       -72                         714                                                     1.21                       -72                         726                           220 mv in                         225 mv in

  **Celilo #4 IC**               1.23                       169                         738                                                     1.24                       168                         744                           700 amps                          719 amps

                                                                                                                                                                                                                                                                       

  **Power Hs #3 IA**             2.57                       -149                        771                           1500/5                    1.82                       -150                        546                           200 mw in                         239 mw in

  **Power Hs #3 IB**             2.60                       91                          780                                                     1.83                       90                          549                           110 mv out                        171 mv out

  **Power Hs #3 IC**             2.60                       -31                         780                                                     1.83                       -31                         549                           550 amps                          815 amps

                                                                                                                                                                                                                                                                       

  **Power Hs #4 IA**             2.46                       -148                        590                           1200/5                    2.51                       -154                        602                           220 mw in                         221 mw in

  **Power Hs #4 IB**             2.46                       92                          590                                                     2.52                       86                          605                           110 mv out                        124 mv out

  **Power Hs #4 IC**             2.46                       -30                         590                                                     2.52                       -35                         605                           600 amps                          609 amps

                                                                                                                                                                                                                                                                       

  **Power Hs #5 IA**             3.49                       -148                        838                           1200/5                    3.67                       -148                        881                           320 mw in                         307 mw in

  **Power Hs #5 IB**             3.55                       92                          852                                                     3.73                       92                          895                           190 mv out                        180 mv out

  **Power Hs #5 IC**             3.53                       -28                         847                                                     3.69                       -28                         886                           880 amps                          854 amps

                                                                                                                                                                                                                                                                       

  **Power Hs #6 IA**             1.52                       -149                        608                           2000/5                    1.67                       -149                        668                           240 mw in                         246 mw in

  **Power Hs #6 IB**             1.60                       90                          640                                                     1.75                       90                          700                           150 mv out                        134 mv out

  **Power Hs #6 IC**             1.58                       -29                         632                                                     1.74                       -29                         696                           700 amps                          673 amps

                                                                                                                                                                                                                                                                       

  **XFMR #2 IA**                 0.52                       5                           312                           3000/5                    0.54                       6                           324                           120 mw out                        120 mw out

  **XFMR #2 IB**                 0.55                       -117                        330                                                     0.55                       -117                        330                           10 mv in                          15 mv in

  **XFMR #2 IC**                 0.53                       122                         318                                                     0.54                       122                         324                           300 amps                          

                                                                                                                                                                                                                                                                       

  **XFMR #5 IA**                 0.49                       0                           392                           4000/5                    0.49                       1                           392                           180 mw out                        189 mw out

  **XFMR #5 IB**                 0.51                       -122                        408                           See Note                  0.52                       -121                        416                           10 mv in                          6 mv in

  **XFMR #5 IC**                 0.51                       116                         408                           Below                     0.51                       118                         408                           400 amps                          

                                                                                                                                                                                                                                                                       

  **XFMR 2&5 IA**                XFMR 5 CTR was later                                                                                                                                                                                                                  
                                 changed to 3000/5 so that                                                                                                                                                                                                             
                                 XFMR 2&5 could be one PMU                                                                                                                                                                                                             
                                 channel.                                                                                                                                                                                                                              

  **XFMR 2&5 IB**                                                                                                                                                                                                                                                      

  **XFMR 2&5 IC**                                                                                                                                                                                                                                                      

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                       

                                 ***Rack 67***                                                                        ***[PTR /]{.underline}*** ***Board Meter Racks***                                                                                                

  ***[Quantity]{.underline}***   ***[Mag.]{.underline}***   ***[Angle]{.underline}***   ***[Primary]{.underline}***   ***[CTR]{.underline}***   ***[Mag.]{.underline}***   ***[Angle]{.underline}***   ***[Primary]{.underline}***   ***[BoardMeters]{.underline}***   ***[Scada]{.underline}***

                                                                                                                                                                                                                                                                       

  **XFMR #1 IA**                 1.16                       -120                        232                           1000/5                    1.24                       -107                        248                           40 mw in                          54 mw in

  **XFMR #1 IB**                 1.21                       134                         242                                                     1.28                       130                         256                           40 mv out                         122 mv out

  **XFMR #1 IC**                 1.11                       10                          222                                                     1.19                       9                           238                           280 amps                          

                                                                                                                                                                                                                                                                       

  **Bus Tie #1 IA**              0.33                       90                          99                            1500/5                    0.33                       90                          99                            0                                 1 mw in

  **Bus Tie #1 IB**              0.33                       -30                         99                                                      0.33                       -30                         99                            40 mv in                          81 mv in

  **Bus Tie #1 IC**              0.33                       -150                        99                                                      0.32                       -150                        96                            100 amps                          195 amps

                                                                                                                                                                                                                                                                       

  **Bus Tie #2 IA**                                                                                                   1500/5                                                                                                                                           

  **Bus Tie #2 IB**                                                                                                                                                                                                                                                    

  **Bus Tie #2 IC**                                                                                                                                                                                                                                                    

                                                                                                                                                                                                                                                                       

  **Bus Tie #3 IA**              0.00                       92                          0                             1500/5                                                                                                                                           

  **Bus Tie #3 IB**              0.00                       -29                         0                                                                                                                                                                              

  **Bus Tie #3 IC**              0.00                       -152                        0                                                                                                                                                                              

                                                                                                                                                                                                                                                                       

  **Midway IA**                  1.31                       -175                        314                           1200/5                    1.33                       -175                        319                           140 mw in                         119 mw in

  **Midway IB**                  1.31                       66                          314                                                     1.33                       67                          319                           10 mv in                          4 mv out

  **Midway IC**                  1.27                       -56                         305                                                     1.29                       -56                         310                           320 amps                          286 amps

                                                                                                                                                                                                                                                                       

  **Troutdale IA**               1.53                       3                           367                           1200/5                    1.47                       3                           353                           150 mw out                        151 mw out

  **Troutdale IB**               1.56                       -114                        374                                                     1.51                       -113                        362                           10 mv in                          8 mv in

  **Troutdale IC**               1.52                       122                         365                                                     1.47                       122                         353                           370 amps                          365 amps

                                                                                                                                                                                                                                                                       

  **Redmond IA**                 1.35                       7                           324                           1200/5                    1.36                       7                           326                           140 mw out                        141 mw out

  **Redmond IB**                 1.38                       -112                        331                                                     1.38                       -112                        331                           20 mv in                          17 mv in

  **Redmond IC**                 1.38                       127                         331                                                     1.38                       127                         331                           340 amps                          340 amps

                                                                                                                                                                                                                                                                       

  **Chemawa IA**                 out                                                                                  800/5                                                                                                                                            

  **Chemawa IB**                 of                                                                                                                                                                                                                                    

  **Chemawa IC**                 service                                                                                                                                                                                                                               

                                                                                                                                                                                                                                                                       

  **Mcloughlin IA**              1.69                       4                           507                           1500/5                    1.68                       3                           504                           220 mw out                        217 mw out

  **Mcloughlin IB**              1.81                       -118                        543                                                     1.80                       -118                        540                           5 mv in                           12 mv in

  **Mcloughlin IC**              1.76                       121                         528                                                     1.74                       120                         522                           530 amps                          521 amps

                                                                                                                                                                                                                                                                       

  **Harvalum IA**                1.03                       -11                         247                           1200/5                    1.07                       -15                         257                           100 mw out                        105 mw out

  **Harvalum IB**                1.01                       -127                        242                                                     1.05                       -131                        252                           50 mv out                         14 mv out

  **Harvalum IC**                1.07                       113                         257                                                     1.10                       109                         264                           260 amps                          254 amps

                                                                                                                                                                                                                                                                       
  ------------------------------ -------------------------- --------------------------- ----------------------------- ------------------------- -------------------------- --------------------------- ----------------------------- --------------------------------- ---------------------------

**[PMU Accuracy Check]{.underline}**

***[All quantities are referenced to "A" phase Bus section #3 1V-0V.
Measurements made on 1/7/98 from 7:30 to 8:30 am]{.underline}***

+--------------+--------+---------+-------------+-------------+-----+
| **Channel &  | **Rack | **Rack  | **Phaser    | **Phaser    | **E |
| Quantity**   | 67     | 67      | Quantity**  | Angle**     | rro |
|              | I      | Input** |             |             | r** |
|              | nput** |         | **(As Read  | **(As Read  |     |
|              |        | **      | in          | in          | *   |
|              | **(    | Angle** | Labview)**  | Labview)**  | *(% |
|              | Second |         |             |             | )** |
|              | ary)** |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **1 - Bus    | 68.817 | ref.    |             |             |     |
| Sect. #3     |        |         |             |             |     |
| VA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **1 - Bus    | 69.101 | -120.10 |             |             |     |
| Sect. #3     |        |         |             |             |     |
| VB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **1 - Bus    | 68.749 | 119.78  |             |             |     |
| Sect. #3     |        |         |             |             |     |
| VC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **1 -        | 68.889 | ref.    | 68.62       | ref.        | 0   |
| Positive     |        |         |             |             | .39 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **2 - Celilo | 1.7913 | ref.    |             |             |     |
| #3 IA**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **2 - Celilo | 1.7933 | -120.10 |             |             |     |
| #3 IB**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **2 - Celilo | 1.7675 | 119.80  |             |             |     |
| #3 IC**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **2 -        | 1.7840 | 10.93   | 0.1807      | 11.12       | 1   |
| Positive     |        |         |             |             | .29 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **3 - Celilo | 1.9895 | 9.80    |             |             |     |
| #4 IA**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **3 - Celilo | 1.9920 | -110.59 |             |             |     |
| #4 IB**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **3 - Celilo | 2.0198 | 130.42  |             |             |     |
| #4 IC**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **3 -        | 2.0004 | 9.88    | 0.2013      | 9.78        | 0   |
| Positive     |        |         |             |             | .63 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **4 - Power  | 1.5096 | -162.31 |             |             |     |
| House #3     |        |         |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **4 - Power  | 1.5239 | 78-07   |             |             |     |
| House #3     |        |         |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **4 - Power  | 1.5447 | -43.44  |             |             |     |
| House #3     |        |         |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **4 -        | 1.5260 | -162.56 | 0.1532      | -162.56     | 0   |
| Positive     |        |         |             |             | .39 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **5 - Power  | 1.1888 | -163.96 |             |             |     |
| House #4     |        |         |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **5 - Power  | 1.1851 | 76.82   |             |             |     |
| House #4     |        |         |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **5 - Power  | 1.2023 | -45.21  |             |             |     |
| House #4     |        |         |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **5 -        | 1.1920 | -164.12 | 0.1202      | -164.02     | 0   |
| Positive     |        |         |             |             | .84 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **6 - Power  | 2.1375 | -162.09 |             |             |     |
| House #5     |        |         |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **6 - Power  | 2.1794 | 78.39   |             |             |     |
| House #5     |        |         |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **6 - Power  | 2.1877 | -42.32  |             |             |     |
| House #5     |        |         |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **6 -        | 2.1682 | -162.00 | 0.2187      | -161.52     | 0   |
| Positive     |        |         |             |             | .87 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **7 - Power  | 1.2933 | -164.01 |             |             |     |
| House #6     |        |         |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **7 - Power  | 1.3590 | 76.19   |             |             |     |
| House #6     |        |         |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **7 - Power  | 1.3511 | -42.66  |             |             |     |
| House #6     |        |         |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **7 -        | 1.3344 | -163.48 | 0.1344      | -163.72     | 0   |
| Positive     |        |         |             |             | .72 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **8 - XFMR   | 0.7961 | -168.11 |             |             |     |
| #2 IA**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **8 - XFMR   | 0.7859 | 72.39   |             |             |     |
| #2 IB**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **8 - XFMR   | 0.7812 | -48.47  |             |             |     |
| #2 IC**      |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **8 -        | 0.7877 | -168.06 | 0.0797      | -167.96     | 1   |
| Positive     |        |         |             |             | .18 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **9 - Midway | 2.2009 | -169.55 |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **9 - Midway | 2.2099 | 72.31   |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **9 - Midway | 2.1572 | -49.61  |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **9 -        | 2.1891 | -168.95 | 0.2157      | -168.46     | 1   |
| Positive     |        |         |             |             | .47 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **10 -       | 1.0949 | 2.14    |             |             |     |
| Troutdale    |        |         |             |             |     |
| IA**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **10 -       | 1.1366 | -114.00 |             |             |     |
| Troutdale    |        |         |             |             |     |
| IB**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **10 -       | 1.0987 | 121.29  |             |             |     |
| Troutdale    |        |         |             |             |     |
| IC**         |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
| **10 -       | 1.1094 | 3.18    | 0.1128      | 3.33        | 1   |
| Positive     |        |         |             |             | .68 |
| Sequence**   |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+
|              |        |         |             |             |     |
+--------------+--------+---------+-------------+-------------+-----+