NYISO OPERATING STUDY

SUMMER 2011

Prepared by

Operations Staff

New York Independent System Operator, Inc.

Approved by NYISO Operating Committee

July 14, 2011
NYISO OPERATING STUDY

SUMMER 2011

Caution and Disclaimer

The contents of these materials are for informational purposes and are provided “as is”

without representation or warranty of any kind, including without limitation, accuracy,

completeness or fitness for any particular purposes. The New York Independent System

Operator (NYISO) assumes no responsibility to the reader or any other party for the

consequences of any errors or omissions. The NYISO may revise these materials at any time in

its sole discretion without notice to the reader.


NYISO OPERATING STUDY

SUMMER 2011

TABLE OF CONTENTS

I. INTRODUCTION........................................................................................................................................................ 2

II. SYSTEM REPRESENTATION AND BASE STUDY ASSUMPTIONS.................................................................................... 2

A.    SYSTEM REPRESENTATION.......................................................................................................................................................2

B. BASE STUDY ASSUMPTIONS ....................................................................................................................................................3

III. DISCUSSION ......................................................................................................................................................... 4

A.    RESOURCE ASSESSMENT .........................................................................................................................................................4

B. CROSS‐STATE INTERFACES ......................................................................................................................................................4

1. Transfer Limit Analysis.................................................................................................................................................4

2. Athens SPS ...................................................................................................................................................................5

3. Sensitivity Testing ........................................................................................................................................................6

4. West Woodbourne Transformer .................................................................................................................................6

5. ConEd – LIPA Transfer Analysis....................................................................................................................................6

6. Transfer Limits for Outage Conditions.........................................................................................................................7

7. Transient Stability and Voltage Limits .........................................................................................................................7

C. THERMAL TRANSFER CAPABILITIES WITH ADJACENT BALANCING AREAS ...........................................................................................8

1. New York – ISO New England Analysis ........................................................................................................................9

2. New York ‐ PJM Analysis............................................................................................................................................10

3. Ontario – New York Analysis......................................................................................................................................11

4. TransÉnergie–New York Interface .............................................................................................................................12

IV. SUMMARY OF RESULTS – THERMAL TRANSFER LIMIT ANALYSIS.......................................................................... 13

APPENDICES

A. SCHEDULE OF SIGNIFICANT INTERCHANGES ASSUMED FOR TRANSFER LIMIT STUDIES

B. SUMMER 2011 BASE CASE CONDITIONS

C. POWER FLOW TRANSCRIPTION DIAGRAMS

D. RATINGS OF MAJOR TRANSMISSION FACILITIES IN NEW YORK

E. INTERFACE DEFINITIONS  

F. ANNOTATED MUST OUTPUT

G. TRANSFER LIMIT SENSITIVITY GRAPHS

H. COMPARISON OF TRANSFER LIMITS: SUMMER 2011 vs. SUMMER 2010

I. GENERATION SHIFTS ASSUMED FOR THERMAL ANALYSIS

J. DISTRIBUTION FACTORS
NYISO OPERATING STUDY

SUMMER 2011

NYISO OPERATING STUDY ‐ SUMMER 2011

I. INTRODUCTION

The following report, prepared by the Operating Studies Task Force (OSTF) at the direction and guidance of

the System Operations Advisory Subcommittee (SOAS), highlights the significant results of the thermal

analysis completed for the summer 2011 capability period.  This analysis indicates that, for the summer 2011

capability period, the New York interconnected bulk power system can be operated reliably in accordance

with the "NYSRC Reliability Rules for Planning and Operating the New York State Power System" and the

NYISO System Operating Procedures.

Transfer limits cited in this report are based on the forecast peak load conditions and are intended as a guide

to system operation.    Changes in generation dispatch or load patterns that significantly change pre‐

contingency line loadings may change limiting contingencies or limiting facilities, resulting in higher or lower

interface transfer capabilities.

System Operators should monitor the critical facilities noted in the enclosed tables along with other limiting

conditions while maintaining bulk system power transfers within secure operating limits.

II. SYSTEM REPRESENTATION AND BASE STUDY ASSUMPTIONS

A. System Representation

The representation was developed from the NYISO Data Bank and assumes the forecast summer

coincident peak load of 32,712 MW.    The other NPCC Balancing Area and adjacent Regional

representations were obtained from RFC‐NPCC summer 2011 Reliability Assessment power flow base

case.

Generation Resource Changes

The generator output levels for major units are summarized in Appendix B, and are consistent with

typical operation for the period.   The inter‐Area schedules represented in the study base case are

summarized in Appendix A.   The following table shows generation retirements and additions since

the summer 2010:

    Retirements

Project Orange 1&2

Energy Systems North East

Westover 8

‐40 MW

‐79 MW

‐81 MW

Greenidge 4  ‐106MW

Total Retirements  ‐306 MW

    Additions

Fairfield Wind Farm 7.4 MW

Gilboa 4 Uprate 30 MW

Empire 571 MW

Astoria Energy II 576 MW

Total Additions 1,184.4 MW

   

   
NYISO OPERATING STUDY

SUMMER 2011

Significant changes since the summer 2010 capability period include:

Transmission Facilities Changes

ConEd M29 Project

Stony Ridge Substation

Luther Forest Project

Watercure 345/230 kV Transformer Bank in‐service

601 NNC in‐service  

BP 76 Remains out‐of‐service

The Consolidated Edison M29 project consists of a circuit from Sprain Brook 345 kV substation to a

new substation, Academy 345 kV, then to two three‐winding 345/138/13.8 transformers and two

138 kV PAR controlled transformers into Sherman Creek 138 kV.

The Luther Forest Project is National Grid’s transmission reinforcement project for their 115 kV

transmission system between Rotterdam Substation and Spier Falls Substation. The Project will be

located in Saratoga County, New York in the Saratoga/Glens Falls area.

The NYSEG/RG&E Stony Ridge Project includes a new Stony Ridge 230 kV substation, which is located

on the Canandaigua‐Hillside 230 kV line, and a step‐down 230/115 kV transformer into a new Sullivan

Park 115 kV substation.

The Watercure 345/230‐kV transformer bank has returned to service for the summer 2011 operating

period.

The NNC 1385 601 line has returned to service for the summer 2011 operating period.

The BP76 remains out‐of‐service for this summer 2011 operating period.

B. Base Study Assumptions

The Siemens PTI PSSTMMUST and PSSTME software packages are used to calculate the thermal limits

based on Normal and Emergency Transfer Criteria defined in the “NYSRC Reliability Rules for Planning

and Operating the New York State Power System".  The thermal transfer limits presented have been

determined for all transmission facilities scheduled in service during the summer 2011 period.

The schedules used in the base case power flow for this analysis assumed a net flow of 1,000 MW

from Public Service Electric & Gas (PSE&G) to Consolidated Edison via the phase‐angle‐regulating

(PAR) transformers controlling the Hudson – Farragut and Linden – Goethals interconnections, and

1,000 MW on the South Mahwah – Waldwick circuits from Consolidated Edison to PSE&G, controlled

by the PARs at Waldwick.  The Branchburg – Ramapo 500 kV (5018) circuit is scheduled in accordance

with the "Ramapo Phase Angle Regulator Operating Procedure", December 11, 1987.    For the

summer 2011 base case, the schedule for the tie is 440 MW from PJM to New York.  These schedules

are consistent with the scenarios developed in the RFC‐NPCC Inter‐Regional Reliability Assessment

for summer 2011, and the MMWG summer 2011 power flow base cases.  The series reactors on the

Dunwoodie – Mott Haven (71 and 72), the Farragut – Gowanus (41 and 42) 345kV and the Sprain

Brook – W. 49th St. (M51 and M52) 345kV cables, as well as the E. 179th St. – Hell Gate (15055) 138kV

feeder are in‐service in the base case.  The series reactors on the Sprain Brook – East Garden City

(Y49) 345kV cable are by‐passed.
NYISO OPERATING STUDY

SUMMER 2011

III. DISCUSSION

A. Resource Assessment

Load and Capacity Assessment

The forecast peak demand for the summer 2011 capability period is 32,712 MW. This forecast is

approximately 427 MW (0.95%) lower than the forecast of 33,025 MW for the summer 2010

capability period, and 914 MW (3.6%) lower than the all‐time New York Control Area (NYCA) seasonal

peak of 33,939 MW, which occurred on August 2, 2006.

The Installed Capacity (ICAP) requirement for the summer period is 37,783MW based on the NYSRC

15.5% Installed Reserve Margin (IRM) requirement for 2011.  NYCA generation capacity for summer

2011 is 38,294 MW, and net external capacity purchases of 1,821MW have been secured for the

summer period.  The combined capacity resources represent a 22.6% margin above the forecast peak

demand of 32,712 MW.

NYISO Peak Load and Capacity Assessment – Summer 2011

NYISO Installed Capacity + 38,294

Special Case Resources + 2,053

Net Capacity Purchases and Sales + 1,821

Scheduled Generation Outages ‐ 0

Allowance for Unplanned Outages ‐ 3,370

Net capacity for load = 38,798

NYISO Forecast Peak ‐ 32,712

Available Reserve = 6,086

Operating Reserve Requirement ‐ 1,800

Net Margin = 4,286

The equivalent forced outage rate is 8.8%, and includes forced outages and de‐ratings based on

historical performance of all generation in the NYCA.  For summer 2010, the equivalent forced outage

rate assumed was 8.4%.

B. Cross‐State Interfaces

1. TRANSFER LIMIT ANALYSIS

This report summarizes the results of thermal transfer limit analyses performed on power system

representation modeling the forecast peak load conditions for summer 2011.    Normal and

emergency thermal limits were calculated according to Normal and Emergency Transfer Criteria

definitions in the “NYSRC Reliability Rules for Planning and Operating the New York State Power

System".    Facility ratings applied in the analysis were from the online MW ratings in the EMS,

and are detailed in Appendix D. Generation shifts assumed for the thermal analysis are detailed

in Appendix I.

Figure 1 presents a comparison of the summer 2011 thermal transfer limits to summer 2010.  

Changes in these limits from the previous years are due to changes in the base case load flow

generation and load patterns that result in different pre‐contingency line loadings, changes in

limiting contingencies, or changes in circuit ratings, or line status.    Appendix H presents a

summary comparison of Cross‐State thermal transfer limits between summer 2011 and 2010,

with limiting element/contingency descriptions.  Significant differences in these thermal transfer
NYISO OPERATING STUDY

SUMMER 2011

limits are discussed below.

UPNY – ConEd interface thermal transfer limit increased by 175 MW. The base flow on the

Pleasant Valley – Long Mountain (398) line decreased, resulting in the unloading of the Athens –

Pleasant Valley (91) and Leeds – Pleasant Valley (92) base flows allowing for a higher transfer

limit.

Sprain Brook – Dunwoodie South interface thermal transfer limit increased by 425 MW. The

addition of the new M‐29 project provides a transfer capability into the Sherman Creek load

pocket of 950 MW. There are two feeders downstream of the Sherman Creek load pocket, which

limit the potential maximum transfers through the pocket to 300 MW. For the purposes of this

study the Academy phase shifters were modeled at 300 MW south. For the generator and phase

shifter schedules assumptions modeled, the resulting distribution of flow resulted in the increase

in thermal transfer capability on the interface.

Figure 1 – Cross‐State Thermal Transfer Limits

2. ATHENS SPS

In 2008 a Special Protection System (SPS) went in‐service, impacting the thermal constraint on

the Leeds to Pleasant Valley 345 kV transmission corridor.    The SPS is designed to reject

generation at the Athens combined‐cycle plant if either the Leeds to Pleasant Valley 345 kV (92)

circuit or the Athens to Pleasant Valley 345kV (91) circuit are out‐of‐service and the flow on the

remaining circuit is above the LTE rating.  Generation at Athens will be tripped until the flow is

below the LTE rating, the out‐of‐service circuit recloses, or the remaining circuit trips.  This SPS is

expected to be active when there is generation on‐line at the Athens station, and will allow the
NYISO OPERATING STUDY

SUMMER 2011

NYCA transmission system to be secured to the STE rating of the 91 line for the loss of the 92

line, and vice‐versa, for normal operating conditions.   The SPS increases the normal thermal limit

to match the emergency thermal limit across the UPNY‐ConEd operating interface when the 91

or 92 are the limiting circuit.  The Table 1 “Emergency” limit for the UPNY‐ConEd interface can be

interpreted as the “Normal” limit, when the Athens SPS is active.

3. SENSITIVITY TESTING

The thermal limits presented in Section IV were determined using the base conditions and

schedules.   The effects of various intra‐  and inter‐Area transfers or generation patterns in the

system are presented in Appendix G.    Certain graphs indicate that there may not be a

measurable sensitivity to the specific variable condition (summer peak load), or the sensitivity

may occur at transfer levels above other transfer constraints (e.g., voltage or transient stability

limitations).   This analysis demonstrates how the particular constraint (thermal transfer limits)

may respond to different conditions.

Phase angle regulator schedules may vary from day‐to‐day.    Sensitivity analysis for selected

interfaces has been included for the Ramapo and St. Lawrence interconnections.    Graphs

showing the sensitivity of the interface limit to the PAR schedule are included in Appendix G.

4. WEST WOODBOURNE TRANSFORMER

The Total‐East interface may be limited at significantly lower transfer levels for certain

contingencies that result in overloading of the West Woodbourne 115/69kV transformer.  

Should the West Woodbourne tie be the limiting facility, it may be removed from service to

allow higher Total‐East transfers.    An over‐current relay is installed at West Woodbourne to

protect for contingency overloads.

5. CONED – LIPA TRANSFER ANALYSIS

Normal transfer capabilities were determined using the base case generation dispatch and PAR

settings as described in Appendix B.    Emergency limits are dispatch dependant, and can vary

based on generation and load patterns in the LIPA system.

For emergency transfer capability analysis, the PARs controlling the LIPA import were adjusted to

allow for maximum transfer capability into LIPA:

ConEd – LIPA PAR Settings

Normal Emergency

Jamaica – Lake Success 138kV  ‐165 MW 85 MW

Jamaica – Valley Stream 138kV  ‐123 MW 90 MW

Sprain Brook – E. Garden City 345kV 630 MW 637 MW

ISO‐NE – LIPA PAR Settings

Norwalk Harbor – Northport 138kV 100 MW 286 MW

The PAR schedules referenced above and the ConEd – LIPA transfer assessment assume a 70%

loss factor and rapid oil circulation in the determination of the facility ratings.

Emergency Transfer via the 138kV PAR‐controlled Jamaica ties between ConEdison and LIPA
NYISO OPERATING STUDY

SUMMER 2011

Con Edison and LIPA have determined possible emergency transfer levels via the Jamaica ‐ Valley

Stream (901) 138kV and Jamaica  ‐  Lake Success (903) 138kV PAR‐controlled ties that could be

used to transfer emergency power between the two entities during peak conditions.    The

emergency transfer levels were calculated in both directions, for system peak load conditions

with all transmission lines in service and all generation available for full capacity.  

ConEd to LIPA emergency assistance  

Based on analysis of historical conditions performed by LIPA and Con Edison, Con Edison

anticipates being able to supply a total flow up to 175 MW of emergency transfer from

Con Edison to Long Island, if requested, via the ties.   

LIPA to ConEd emergency assistance  

LIPA anticipates being able to supply a total flow up to 459 MW of emergency transfer

from Long Island to Con Edison, if requested, via the ties.

6. TRANSFER LIMITS FOR OUTAGE CONDITIONS

Transfer limits for scheduled outage conditions are determined by the NYISO Scheduling and

Market Operations groups.    The NYISO Real‐Time Dispatch system monitors the EHV

transmission continuously to maintain the secure operation of the interconnected system.

7. TRANSIENT STABILITY AND VOLTAGE TRANSFER LIMITS

The thermal interface transfer limits in Section IV do not include the results of transient stability

testing or voltage transfer limit analyses.  The current all lines in service and maintenance outage

transient stability and voltage stability interface limits, are summarized and available through the

NYISO website located at:

http://www.nyiso.com/public/markets_operations/market_data/reports_info/index.jsp
NYISO OPERATING STUDY

SUMMER 2011

Thermal Transfer Capabilities with Adjacent Balancing Areas

Figure 2 – Inter‐Area Thermal Transfer Capabilities1

Thermal transfer limits between New York and adjacent Balancing Areas are also determined in this

analysis.    These transfer limits supplement, but do not change, existing internal operating limits.  

There may be facilities internal to each system that may reduce the transfer limits between Balancing

Areas.  Reductions due to these situations are considered to be the responsibility of the respective

reliability authority.    Some of these potential limitations are indicated in the summary tables by

“[Reliability Coordinating] Facility” limits, which supplement the “Direct Tie” limits between the

Balancing Areas.    Transfer conditions within and between neighboring Balancing Areas can have a

significant effect on inter‐ and intra‐Area transfer limits.   Coordination between Balancing Areas is

necessary to provide optimal transfer while maintaining the reliability and security of the

interconnected systems.

Significant differences in these thermal transfer limits are discussed below.

New England – New York interface thermal transfer limit increased by 150 MW as a result of

several factors. The two main factors are the 601 NNC Norwalk Harbor – Northport line being

 

1 TE‐NY transfer capabilities shown in Figure 2 are not thermal transfer limits; for more information see Section

III.B.4.
NYISO OPERATING STUDY

SUMMER 2011

modeled in‐service and redistribution of New England generation in the Southern Connecticut

area, reducing the pre‐flow on the Alps – Berkshire (393) 345 kV and Pleasant Valley – Long

Mountain (398) 345 kV lines.   

New York – New England interface thermal transfer limit was increased by 300MW. The

increase in generation in the Southern Connecticut area supported a higher limit through the

reduction of the pre‐flow on the Pleasant Valley – Long Mountain (398) 345 kV line. The thermal

transfer capability was reduced with the scheduling of PV‐20 at zero rather than 150 MW for the

transfer. A further reduction of 146 MW resulted from a 69 MW reduction in the Pleasant Valley

– Long Mountain (398) 345 kV line rating relative to the summer 2010 analysis. The net effect of

these factors was a 300 MW increase in New York to New England transfer capability.

New York – PJM interface thermal transfer limit was affected in both directions due to changes

in dispatch assumptions and the return of the Watercure 345/230 kV transformer.

8. NEW YORK – ISO NEW ENGLAND ANALYSIS

a) New England Transmission/Capacity Additions

Transmission

New England had a number of new transmission facilities installed since the last

operating period. Among the most significant transmission upgrades completed in New

England for this operating period were: the installation of the Limekiln 115 kV

substation between East Ave. and Essex‐Tap and the Lyndonville substation between St

Johnsbury and Irasburg in the Vermont transmission system.  Also, two new 345 /115

kV facilities called Newfane and Vernon VT were completed with lines 379, 381, 340,

3340 and 3381 re‐terminated at the new Vernon VT 345 kV substation.  Several other

less critical transmission upgrades in New Hampshire, Southeast Massachusetts (NEEWS

Project) and Maine (MPRP Project) are currently under construction and will likely be

included in the next operating period.  

   

Capacity

In the New England Balancing Area, 897 MW of new capacity has been or will be added

since the previous summer operating period prior to the end of the 2011 summer

operating period. Of this total new capacity, Kleen Energy is the largest generator (619.8

MW) followed by several other smaller generators (both thermal and wind) with a

commercial operation scheduled for the summer of 2011.   

b) Thermal Transfer Limit Analysis

The transfer limits between the NYISO and ISO New England for normal and emergency

transfer criteria are summarized in Section IV, Table 2.

c) Cross‐Sound Cable

The Cross‐Sound Cable is an HVdc merchant transmission facility connecting the New

Haven Harbor 345kV (United Illuminating, ISO‐NE) station and Shoreham 138kV (LIPA,

NYISO) station.  It has a design capacity of 330MW.  This facility is not metered as part

of New York‐New England interface, and HVdc transfers are independent of transfers

between the NYISO and ISO‐NE.

d) Smithfield – Salisbury 69kV

CHG&E and Northeast Utilities will operate the Smithfield ‐ Salisbury 69 kV (FV/690) line
NYISO OPERATING STUDY

SUMMER 2011

normally open during the summer period due to post‐contingency limits within the

Northeast Utilities system. When the ISO‐NE to NYISO transfer is less than

approximately 400 MW, however, the line may be closed.  When closed, the maximum

allowable flow on this line is 28 MVA based on limitations in the Northeast Utilities 69

kV system.  The FV/690 line has directional over‐current protection that will trip the line

in the event of an overload when the flow is into Northeast Utilities.  This facility will not

limit transfers between NYISO and ISO‐NE.

e) Northport ‐ Norwalk Harbor Cable Flow

Flow on the NNC Norwalk Harbor to Northport, facility is controlled by a phase angle‐

regulating (PAR) transformer at Northport.  As system conditions vary the following may

be used to optimize transfer capability between the Balancing Areas.    The thermal

transfer limits are presented in Table 2 for two different PAR schedule assumptions on

the Northport – Norwalk Harbor interconnection.    Exhibits in Appendix G graphically

demonstrate the optimization of transfer capability by regulating the flow on the

Northport‐Norwalk Harbor tie.

f) Whitehall – Blissville 115kV

The phase angle regulator on this circuit will control pre‐contingency flow between the

respective stations.    VELCO, National Grid, ISO‐NE and NYISO developed a joint

operating procedure.  For the summer 2011 analyses, the pre‐contingency schedule is 0

MW from Blissville (ISO‐NE) to Whitehall (NYISO).  The scheduled flow may be adjusted

to protect the National Grid local 115kV transmission south of Whitehall for 345kV

contingency events in southern Vermont.

g) Plattsburgh – Sand Bar 115 kV (i.e. PV20)

The phase angle regulating transformer at the VELCO Sand Bar substation was modeled

holding a pre‐contingency flow of approximately 0 MW on the PV20 tie.  This modeling

assumption was premised upon common operating understandings between ISO‐NE

and the NYISO given local operating practice on the Moses – Willis – Plattsburgh 230 kV

transmission corridor. ISO‐NE’s analysis examined and considered New England system

limitations given this modeling assumption and did not examine generation dispatch /

system performance on the New York side of the PV20 tie for this analysis.  

h) Transient Stability Limitations

For certain system configurations, stability performance determines the transfer

capability between the Balancing Areas.    For those instances, the limits have been

obtained from the report "1992‐1996 NYPP‐NEPOOL TRANSFER LIMIT STUDY ‐ OCTOBER

1992."    A new study of NYISO‐ISO‐NE transfer capability through 2009, including

transient stability assessment, was approved in May 2007.

The stability limits are expressed in terms of the transfer on the "Northern Ties", i.e.,

excluding flow on the Norwalk Harbor – Northport circuit.  Stability limits for transfers

from New England to New York are a function of the New England MW load level, and

include the effect of Northfield and Bear Swamp in the generating and pumping modes.

9. NEW YORK ‐ PJM ANALYSIS

a) Thermal Transfer Limit Analysis
NYISO OPERATING STUDY

SUMMER 2011

The transfer limits for the New York ‐ PJM interface are summarized in Section IV, Table

3.  The phase angle regulating transformers controlling the Branchburg – Ramapo 500

kV circuit are used to maintain flow at the normal rating of the Ramapo 500/345 kV

transformer (1,000 MW) in the direction of the transfer.

b) Opening of PJM ‐ New York 115 kV Ties as Required

The normal criteria thermal transfer limits presented in Section IV were determined for

an all lines in‐service condition.  The 115kV interconnections between GPU Energy and

New York (Warren ‐ Falconer, North Waverly ‐ East Sayre, and Laurel Lake ‐ Westover)

may be opened in accordance with NYISO and PJM Operating Procedures provided this

does not cause unacceptable impact on local reliability in either system.  Over‐current

protection is installed on the Warren  ‐  Falconer and the North Waverly  ‐  East Sayre

115kV circuits; either of these circuits would trip by relay action for an actual overload

condition.  There is no overload protection on the Laurel Lake ‐ Westover circuit, but it

may be opened by operator action if there is an actual or post‐contingency overload

condition.   However, opening the Laurel Lake – Westover tie could potentially cause

local thermal and pre‐  and post‐contingency voltage violations for the 34.5 kV

distribution system within New York.  Sensitivity analysis performed indicated that the

thermal and voltage conditions were exacerbated for conditions that modeled high

simultaneous interface flows from New York to PJM and New York to Ontario.   

10. ONTARIO – NEW YORK ANALYSIS

a) Thermal Transfer Limit Analysis

The thermal limits between the New York ISO and the Independent Electricity System

Operator (IESO‐Ontario) Balancing Areas for normal and emergency transfer criteria are

presented in Section IV, Table 4. The transfer limits are determined for two assumed

schedules on the phase angle regulating transformers controlling the L33P and L34P

interconnections at St. Lawrence.

The Beck‐Packard (BP76) 230kV tie between Ontario and New York will be out of service

for the summer 2011 period.

Transient Stability Limitations

Transient stability limits for the NYISO ‐ IESO interconnection are reported in "NYPP‐OH

TRANSIENT STABILITY TESTING REPORT on DIRECT TIE TRANSFER CAPABILITY ‐ OCTOBER

1993."   

b) Ontario – Michigan PARs

As of the time of this writing, the required agreements to have all these PARs in service

have not been completed; therefore the status of the Phase Angle Regulating

transformers between Ontario and Michigan in the summer 2011 is anticipated to be as

follows:

Operating conditions Normal Emergenc

y

Lambton – St. Clair   L4D 345 kV O/S I/S

Lambton – St. Clair L51D 230 kV O/S I/S

Keith – Waterman   J5D 230 kV I/S I/S

Scott – Bunce Creek   B3N 230 kV O/S O/S
NYISO OPERATING STUDY

SUMMER 2011

Current plans suggest all four PARS could be available by Q4 2011. Once in service, the

PARs would help ensure scheduled flows are maintained on the Ontario‐Michigan

interface.  

The IESO performed additional thermal simulations with the PARs bypassed in normal

operation as shown in the table above. The results of the TLTG simulations performed

by the IESO indicate that the limits presented in table 4 are appropriate for the

upcoming summer 2011.

c) Generation Rejection for Loss of L33P/L34P‐St. Lawrence Ties

The interface limits were determined for a particular load, transmission and generation

pattern.    When system conditions vary from those forecast in the study, normal

interface limits may vary.   Generation rejection special protection systems (SPSs) are

available at Beauharnois, St. Lawrence/Saunders, and St. Lawrence/FDR to reject

generation for the loss of the L33P and/or L34P interconnections. Ontario or NYPA

operators consistent with system conditions can select these SPSs.

The tie‐line L33P is more limiting than L34P because of the lower rating of its phase

shifter (PAR).  The limiting STE rating of the L33P PAR is 334 MVA at 40 degrees phase

shift. The outage distribution factor (ODF) on L33P for the loss of L34P is 0.559 and the

ODF of L34P for the loss of L33P is 0.601. Assuming matching schedules, the total flow

on both circuits should not exceed 400 MW. Nevertheless, according to the document

“Ontario Transmission System”, the transfer at St. Lawrence should not be scheduled to

higher than 300MW.

11. TRANSÉNERGIE–NEW YORK INTERFACE

Thermal transfer limits between TransÉnergie (Hydro‐Quebec) and New York are not analyzed as

part of this study.    Respecting the NYSRC and NYISO operating reserve requirements, the

maximum allowable day‐ahead delivery into the NYCA from TransÉnergie on the Chateauguay –

Massena (MSC‐7040) 765kV tie is limited to 1,200 MW plus an additional 300 MW wheel‐

through transaction to another Balancing Area for a total of 1,500 MW.  However, in real‐time

the total flow is limited to 1,800 MW based on system conditions; the additional flow is an

hourly wheel‐through transaction to another Balancing Area.  Maximum delivery from NYCA to

Quebec on the 7040 line is 1,000 MW.
NYISO OPERATING STUDY

SUMMER 2011

IV. SUMMARY OF RESULTS – THERMAL TRANSFER LIMIT ANALYSIS

Table 1 – NYISO CROSS STATE INTERFACE THERMAL LIMITS

• Table 1.a

o Dysinger East

o West Central

o UPNY – ConEd

o Sprain Brook – Dunwoodie So.

o ConEd – LIPA Transfer Capability

• Table 1.b – MSC‐7040 Flow Sensitivity

o Central East

o Total East

o Moses South

Table 2.a – NYISO to ISO‐NE INTERFACE THERMAL TRANSFER LIMITS

• Northport‐Norwalk Flow Sensitivity

Table 2.b – ISO‐NE to NYISO INTERFACE THERMAL TRANSFER LIMITS

• Northport‐Norwalk Flow Sensitivity

Table 3.a – NYISO to PJM INTERFACE THERMAL TRANSFER LIMITS

• 3‐115 kV Ties I/S and O/S

Table 3.b – PJM to NYISO INTERFACE THERMAL TRANSFER LIMITS

• 3‐115 kV Ties I/S and O/S

Table 4 – NYISO ‐ IESO INTERFACE THERMAL TRANSFER LIMITS

• L33/34P Flow Sensitivity
NYISO OPERATING STUDY

SUMMER 2011

TABLE 1.a

NYISO CROSS‐STATE INTERFACE THERMAL TRANSFER LIMITS‐SUMMER 2011

ALL LINES I/S

Dysinger East West Central UPNY ‐ ConEd1

Sprain Brook

Dunwoodie ‐ So.

ConEd – LIPA

Transfer

Capability

NORMAL 2900 (1) 1600 (1) 3750 (3) 3850 (5) 850 (7)

EMERGENCY 3200 (2) 1900 (2) 4400 (4) 4175 (6) 1400 (8)

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) Niagara – Rochester (NR2) 345 kV LTE 1501 MW L/O AES/Somerset – Rochester (SR1‐39) 345 kV

(2) Niagara – Rochester (NR2) 345 kV STE 1685 MW L/O AES/Somerset – Rochester (SR1‐39) 345 kV

(3) Leeds – Pleasant Valley (92) 345 kV LTE 1538 MW L/O Athens – Pleasant Valley (91) 345 kV

(4) Leeds – Pleasant Valley (92) 345 kV STE 1723 MW L/O Athens – Pleasant Valley (91) 345 kV

(5) Mott Haven – Rainey (Q11) 345 kV SCUC2 920 MW L/O Mott Haven – Rainey (Q12) 345 kV  

Rainey 345/138 kV transformer

(6) Mott Haven – Rainey (Q11) 345 kV STE 1075 MW L/O Mott Haven – Rainey (Q12) 345 kV  

(7) Dunwoodie – Shore Rd. (Y50) 345 kV LTE 877 MW L/O (SB RNS2 @ Sprain Brook 345 kV)

Sprain Brook – East Garden City (Y49) 345 kV

Sprain Brook – Academy (M29) 345 kV

(8) Dunwoodie – Shore Rd. (Y50) 345 kV NOR 599 MW    Pre‐Contingency Loading

  

1 See Section III.B.2 for discussion on Athens SPS

2 The rating used for cable circuits during SCUC reliability analysis is the average of the LTE and STE rating (SCUC Rating).  
NYISO OPERATING STUDY

SUMMER 2011

TABLE 1.b

NYISO CROSS‐STATE INTERFACE THERMAL TRANSFER LIMITS‐SUMMER 2011

ALL LINES I/S

MSC‐7040 FLOW

800 MW

MSC‐7040 FLOW

1200 MW

MSC‐7040 FLOW

1600 MW

CENTRAL EAST     

NORMAL 2850 (1) 2875 (1) 2900 (1)

EMERGENCY 3150 (2) 3175 (2) 3200 (2)

TOTAL EAST     

NORMAL 5025 (3) 5050 (3) 5100 (3)

EMERGENCY 5925 (2) 5875 (2) 5825 (2)

MOSES SOUTH     

NORMAL 2250 (4) 2200 (4) 2150 (4)

EMERGENCY 2700 (5) 2650 (5) 2600 (5)

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) New Scotland – Leeds (93) 345 kV LTE 1538 MW L/O New Scotland – Leeds (94) 345 kV

(2) New Scotland – Leeds (93) 345 kV STE 1724 MW L/O New Scotland – Leeds (94) 345 kV

(3) Fraser – Coopers Corners (33) 345 kV LTE 1404 MW L/O Double‐circuit Tower 31&41

Marcy – Coopers Corners (UCC2‐41) 345 kV

Porter – Rotterdam (31) 230 kV

(4) Marcy 765/345 T2 transformer LTE 1650 MW L/O Marcy 765/345 T1 transformer

(5) Marcy 765/345 T2 transformer STE 1971 MW L/O Marcy 765/345 T1 transformer
NYISO OPERATING STUDY

SUMMER 2011

TABLE 2.a

NYISO to ISO‐NE INTERFACE THERMAL TRANSFER LIMITS ‐ SUMMER 2011

ALL LINES I/S

New York to

New England DIRECT TIE NYISO FACILITY ISO‐NE FACILITY

Northport –Norwalk

100MW

NORMAL 1700 (1) 2275 (3) 1700 (5)

EMERGENCY 2275 (2) 2275 (4) 1700 (5)

      

    Northport –Norwalk

0 MW

NORMAL 1650 (1) 2300 (3) 1650 (5)

EMERGENCY 2225 (2) 2300 (4) 1650 (5)

NOTE:  Northport – Norwalk Harbor flow is positive in the direction of transfer

The Northport – Norwalk Harbor (NNC) line is no longer part of the New York‐New England Interface Definition

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) Pleasant Valley  –  Long Mountain (398) 345 kV LTE 1317 MW L/O SB:MILLST 3:14T

Beseck – Millstone (348) 345 kV

Millstone G3 24 kV

(2) Pleasant Valley  –  Long Mountain (398) 345 kV STE 1599 MW L/O Millstone G3 24.0 kV

(3) Reynolds Rd – Greenbush (9) 115 kV LTE 398 MW L/O New Scotland – Alps (2) 345 kV

(4) Reynolds Rd – Greenbush (9) 115 kV STE 398 MW L/O New Scotland – Alps (2) 345 kV

(5) Bear Swamp – Pratts Junction (E 205E) 230 kV STE 409 MW L/O HVDC Phase 2
NYISO OPERATING STUDY

SUMMER 2011

TABLE 2.b

ISO‐NE to NYISO INTERFACE THERMAL TRANSFER LIMITS ‐ SUMMER 2011

ALL LINES I/S

New England to

New York DIRECT TIE NYISO FACILITY ISO‐NE FACILITY

Norwalk –Northport

100MW

NORMAL 1950 (1) 2550 (3) 1525 (7)

EMERGENCY 2400 (2) 3275 (4) 1550 (8)

     

    Norwalk–Northport

200MW

NORMAL 1525 (5) 2525 (3) 1600 (8)

EMERGENCY 2150 (6) 3275 (4) 1650 (8)

NOTE:  Norwalk Harbor – Northport schedule is positive in the direction of transfer.

The Northport – Norwalk Harbor (NNC) line is no longer part of the New York‐New England Interface Definition  

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) Pleasant Valley  –  Long Mountain (398) 345 kV LTE 1317 MW L/O    Alps –Berkshire (398) 345 kV

  Berkshire – Northfield Mount (312) 345 kV

  Berkshire 345/115 kV Transformer

(2) Pleasant Valley  –  Long Mountain (398) 345 kV NORM 1135 MW    Pre‐Contingency Loading

(3) Alps –  New Scotland (2) 345 kV LTE 1326 MW L/O    Pleasant Valley – Long Mountain (398) 345 kV  

(4) Alps –  New Scotland (2) 345 kV STE 1685 MW L/O    Pleasant Valley – Long Mountain (398) 345 kV

(5) Northport – Norwalk Harbor (NNC) 138 kV LTE 513 MW L/O Pleasant Valley –  Long Mountain (398) 345 kV

Pleasant Valley –  East Fishkill (F37) 345 kV

(6) Northport – Norwalk Harbor (NNC) 138 kV STE 641 MW L/O Pleasant Valley –  Long Mountain (398) 345 kV

(7) Norwalk Junction – Archers Lane  

(3403C) 345kV

LTE 850 MW L/O    Southington 5T Stuck Breaker

(8) Norwalk Junction – Archers Lane  

(3403C) 345kV

LTE 850 MW L/O    Long Mountain – Frost Bridge (352) 345 kV
NYISO OPERATING STUDY

SUMMER 2011

TABLE 3.a

NYISO to PJM INTERFACE THERMAL TRANSFER LIMITS ‐ SUMMER 2011

ALL LINES I/S

NYISO to PJM DIRECT TIE NYISO FACILITY PJM FACILITY

NORMAL 2175 (1) 2875 (3) 2450 (4)

3‐115‐O/S 2700 (2) 2825 (3a) 2950 (5)

EMERGENCY 2275 (6)    2450 (4)

3‐115‐O/S 2825 (7)    2950 (5)

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) North Waverly – East Sayre (956) 115kV LTE 128 MW L/O East Towanda – Hillside (70) 230 kV

   

(2) Hillside – East Towanda (70)  230 kV LTE 531 MW L/O (Tower 41 &33)

Coopers Corners  –  Fraser (33) 345kV

Coopers Corners  –  Marcy (UCC2‐41) 345 kV

(3) Hillside – Chemung  115 kV LTE 176 MW L/O   Hillside – East Towanda (70)  230 kV

(3a) Dunkirk – South Ripley (68)  230 kV LTE 530 MW L/O Wayne – Handsome Lake 345kV

(4) Tiffany – Laurel Lake 115 kV EMER 149 MW L/O Grover – East Towanda 230 kV

East Towanda – Hillside (70) 230 kV

East Towanda 230/115 kV transformer

East Sayre – North Waverly (956) 115 kV

(5) Homer City – Shelocta 230 kV EMER 841 MW L/O Wayne – Handsome Lake 345kV

(6) North Waverly – East Sayre (956) 115kV STE 143 MW L/O East Towanda – Hillside (70) 230 kV

   

(7) Hillside – East Towanda (70) 230 kV   STE 554 MW L/O Susquehanna G1

NOTE:  Emergency Transfer Capability Limits may have required line outages as described in Section III.C.2.  PAR

schedules have been adjusted in the direction of transfer.  
NYISO OPERATING STUDY

SUMMER 2011

TABLE 3.b

PJM to NYISO INTERFACE THERMAL TRANSFER LIMITS ‐ SUMMER 2011

ALL LINES I/S

PJM to NYISO DIRECT TIE NYISO FACILITY PJM FACILITY

NORMAL 1925 (1) 2750 (6) 2575 (3)

3‐115‐O/S 3000 (2) 2900 (6) 3425 (9)

EMERGENCY 1950 (4) 2925 (8)     2675 (7)

3‐115‐O/S 3025 (5) 3075 (8) 3450 (10)

LIMITING ELEMENT Rating    LIMITING CONTINGENCY

(1) Falconer – Warren (171) 115 kV LTE 120 MW L/O Erie East – Erie South East 230 kV

(2) South Ripley – Erie East (69) 230 kV LTE 607 MW L/O Stolle Rd. – Homer City (37) 345 kV  

(3) Towanda – East Sayre 115 kV EMER 155 MW L/O (Stuck Breaker  Hillside 230 kV)

Canandaigua – Stony Ridge 230 kV

Hillside – Watercure 230 kV

Hillside – East Towanda 230 kV

Hillside 230/34.5 kV Transformer

(4) Falconer – Warren (171) 115kV NORM 82 MW L/O Pre‐Contingency Loading  

(5) South Ripley – Erie East (69) 230 kV STE 617 MW L/O Stolle Rd. – Homer City (37) 345 kV  

(6) North Waverly – Lounsberry 115 kV LTE 131 MW L/O Oakdale – Watercure (31) 345 kV

Oakdale 345/115 kV Transformer

(7) East Towanda – East Sayre 115 kV EMER 155 MW L/O Hillside – East Towanda (70) 230 kV

(8) North Waverly – Lounsberry 115 kV   STE 143 MW L/O Oakdale – Watercure (31) 345 kV

(9) Oxbow – Lackawanna 230 kV EMER 617 MW L/O Chapman – Lobo (37) 230 kV

(10) Oxbow – Lackawanna 230 kV NORM 488 MW    Pre‐Contingency Loading

NOTE:  Emergency Transfer Capability Limits may have required line outages as described in Section III.C.2.  PAR

schedules have been adjusted in the direction of transfer.  
NYISO OPERATING STUDY

SUMMER 2011

TABLE 4

NYISO ‐ IESO INTERFACE THERMAL TRANSFER LIMITS ‐ SUMMER 2011

BP76 O/S

DIRECT

TIE

NYISO

FACILITY

IESO

FACILITY

DIRECT

TIE

NYISO

FACILITY

IESO

FACILITY

Ontario to

New York

L33/34P

0 MW    

L33/34P

300 MW

NORMAL 1575 (1) 1175 (2) 1500 (3) 1900 (1) 1600 (2) 1775 (3)

EMERGENCY 1875 (4) 1650 (5) 2475 (6) 2175 (4) 2075 (5) 2750 (6)

New York to

Ontario   

L33/34P

0 MW    

L33/34P

300 MW   

NORMAL 925 (7)    450 (8) 1225 (7)    750 (11)

EMERGENCY 1325 (9)    1100 (10) 1625 (9)    1350 (10)

LIMITING ELEMENT Rating LIMITING CONTINGENCY

(1) Beck – Niagara (PA27) 230 kV   LTE 460 MW L/O Beck – Niagara (PA 302) 345 kV

(2) Niagara – Rochester (NR‐2) 345 kV LTE 1501 MW L/O AES/Somerset ‐ Rochester (SR‐1) 345 kV  

(3) Q25BM 230 kV LTE 436 MW L/O Q23BM + Q24HM 230 kV

(4) Beck – Niagara (PA27) 230 kV   STE 558 MW L/O Beck – Niagara (PA 302) 345 kV

(5) Niagara – Rochester (NR‐2) 345 kV STE 1685 MW L/O AES/Somerset ‐ Rochester (SR‐1) 345 kV  

(6) Q23BM 230 kV STE 447 MW L/O Q25BM 230 kV

(7) Beck – Niagara (PA27) 230 kV LTE 460 MW L/O Beck – Niagara (PA 301) 345 kV  

Beck #2 GS19 & G20

(8) Q24H 230 kV LTE 493 MW L/O Q25BM + Q29HM 230 kV

(9) Beck – Niagara (PA27) 230 kV   NOR 400 MW    Pre‐Contingency Loading

(10) Q30M 230 kV STE 426 MW L/O Q29HM 230 kV

(11) Q29HM 230 kV LTE 500 MW L/O Q23BM + Q24HM 230 kV