Field Flashing Synchronous Generator

The goal of this project is to create a black start system for a 15-kVA synchronous generator system in the University of Idaho Model Power System Lab. Team members will design the system, simulate using RTDS system modeling, install the system, and then conduct tests. This project is sponsored by Schweitzer Engineering Laboratories and is advised by professors in the University of Idaho electrical engineering department.
==Problem Definition==
When power goes completely out, it is necessary to excite the fields of power system generators with battery power to re-start the generators before switching back to using generator output power for field excitation; this is known as a black start.
We are designing a black start field exciter system for the 15kVA synchronous generator in the Buchanan Engineering Power Lab to be used for research on black start conditions.
===Background===
When power has been completely or partially lost in a grid, a black start procedure is required to restore generation capabilities. In some cases, diesel generators are used to start the larger main power generators. In the northwest, hydroelectric stations are the common black-start sources. The advantage of hydroelectric power is that the only requirement is that the turbines spin by having the intake gates open and the generator field coils be excited.
===Deliverables===
* Black Start System for GJL 15 kVA Generator:
** ABB Field Exciter
** Battery Bank 
** Exciter Power Supply Transfer Switch
** Battery Bank
** Transfer Switch Controller
 
* Validation/improvement of existing RTDS model
* Model of black start on RTDS simulation
* Documentation of black start system operating procedures for future work
==Specifications==
===System Process===
#	Prime mover spins rotor to initiate a black start
#	Battery bank provides excitation voltage and current directly to generator sufficient power is provided from synchronous generator to run the field exciter
#	Black start system controls transfer of exciter power supply from batteries to generator power.
#	Generator reaches rated output power.
#	ABB field exciter controls excitation in steady state operation
===Specs Table===
Specific Requirement 	Description	Target 	Acceptable Performance	Final Design
Size 	
The Black Start System should 
take up a minimal amount of space 
in the BEL Power Lab.	36" x 48" x 36""	
All dimensions 
smaller than Target.	6” x 12” x 18”
"Normal" 
Operating Range	
Normal current through 
the transfer switch 
at rated conditions.	
25 Amps DC and AC	
Can sustain 20 Amps or Better	
Switch does not carry full field current.
Battery connected to field with
25A rated TE RM8 Relay with 60A surge rating.
Transfer Switch Control 	
Controller determines when generator 
output is sufficient to 
operate the exciter.	I/O ports capable of driving transfer switch
command inputs. Communicate with exciter to
utilize exciter voltage sensors on 
generator output terminals	I/O ports capable of driving 
transfer switch command inputs.
Uses separate voltage/current sensors	
Local Manual Control or 
automatic battery disconnect with 
UNITROL 1020 FCB command DIO signal.
Forcing Output 	
The transfer switch must be capable 
of supplying a short term 
"burst" of power to the generator.	
Up to 45 Amp AC or DC 
Lasts more than 10 seconds	
Sustain 45 Amp DC 
for 10 seconds	
Switch does not carry full field current.
Battery connected to field with
25A rated TE RM8 Relay with 60A surge rating.
Exciter DC supply Voltage	
Battery bank voltage supplied 
to exciter during black start	
24 VDC 	
Min 18VDC Max 300 VDC	
Experimental data shows 
UNITROL 1020 AUX input powers on at 12.0V.
Using FIAMM 12V 7Ah sealed lead acid battery
Display 	
The black start system should indicate
the power source being used 
to power the exciter	
Indicate power source 
record transfer time	
Indicate power source	
Indicates black start active or battery charging
==System Design==
===System Circuit===
System Process: Local Control
1. Prime mover spins rotor to initiate a black start
2. User turns selector switch to ON position to connect battery to black start system and power on ABB AUX power supply to AVR control system.
3. User presses momentary button 1 to turn relay on connecting batteries to field windings of generator.
4. Battery bank provides excitation current directly to generator. Sufficient power is provided from synchronous generator to run the ABB field exciter PWR inputs.
5. User releases button 2 disconnecting batteries from field.
6. UNITROL 1020 to starts its excitation current output in soft-start ramp up.
7. ABB field exciter controls excitation in steady state operation.
8. User turns selector switch to charge position to connect batteries to charger.
===Design Prototype===
Front of Prototype Board	Front Connections
 	
*VBatt+: Positive connection from battery 
*VBatt-: Negative connection from battery 
*Ie+: Positive connection to field windings 
*Ie-: Negative connection to field windings 
*Remote: Available ports for automatic switching from AVR exciter
Back of Prototype Board	Back Description
 	
Element details:
*Resistor: 1.0 Ohm
*Relay: Electromechanical Relay
*Switch: Standard mechanical switch
<youtube>3iTTyLb7IMw</youtube>
===Final System Design===
Front of Black-Start board	
 No Excitation to System	
 Attempt to Start Generator With AVR	
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===RTDS===
 RTDS Complete System Model 
This model includes
*Black Start System
**Dial for switching between system steps
**Selector switch for system step selection
***Step 1: No excitation to synchronous generator
***Step 2: Excitation provided from battery
***Step 3: Excitation is switched from battery to AVR
*ABB AVR exciter
*Dynamic RL Load
*3-phase RMS Meter
*Rotor speed slider
*Per-unit to SI unit conversion	
 No Excitation to System 
With no excitation provided from the AVR or battery the following changes occur: 
*Total field current (IF) = 0
*AVR field voltage (Ef) = 0
*Total field voltage (Ef_total) = 0
*RMS bus voltage (BusRMS) = 0	
 Battery Excitation 
When introducing the battery to the field windings circuit, a field current is then created which then allows the synchronous generator to produce a terminal voltage. The terminal voltage is much less than the rated voltage thus the AVR has to be brought into the system in the next step. 
*Total field current (IF): Ramps up to 0.06-pu
*AVR field voltage (Ef): irrelevant
*Total field voltage (Ef_total): Instant step change to 0.4-pu
*RMS bus voltage (BusRMS) = Ramps up to 40.26-V	
 Switch from Battery to AVR Excitation 
With the AVR brought into the system and the battery disconnected, the AVR takes control of the field excitation. The terminal voltage created by the battery is enough to allow the AVR to remain powered while this transition occurs. The total field voltage is now instantly influenced by the AVR which allows the terminal voltage of the synchronous generator to reach the rated voltage (240-V).
*Total field current (IF): Logarithmic increase to 1.75-pu
*AVR field voltage (Ef): Exponential increase from 0.915-pu to 1.75-pu
*Total field voltage (Ef_total): Exponential increase from 0.4-pu to 1.75-pu
*RMS bus voltage (BusRMS): Ramped increase from 40-V to 240-V	
 Steady-State Operation 
This model includes
*Total field current (IF) = 1.75-pu
*AVR field voltage (Ef) = 1.75-pu
*Total field voltage (Ef_total) = 1.75-pu
*RMS bus voltage (BusRMS) = 240-V (rated voltage)	
==Project Learning==
===ABB AVR===
===Planned Tests for Exciter System===
1. Check that DCH Supervision Alarm works
Attach UNITROL PRW and Generator monitor inputs to autotransfromer output from lab voltage supply. 
Connect UNITROL field output to dummy RL load simulating motor field windings 
Increase voltage out of autotransformer to simulate generator output ramping up as field current builds.
Verify that DCH Supervision Alarm bit toggles at expected setpoint
2. Test field Excitation with 24 VDC source
Run generator with VFD controlled motor
Apply 24VDC from power lab DC power supply to field winding circuit to simulate the proposed battery bank. Use power supply current limit to prevent excessive current then remove current limit and test power resistors in series with source to limit current.
Observe generator output voltage rise time and final value with 24VDC excitation.
==Team Information==
Team "Flash" 	Team "Flash" 	Team "Flash" 	Team "Flash"	Team "Flash"	Team "Flash"
Picture 	Biography 	Discipline 	 	 	
Will Parker 	Will is a senior in electrical engineering from Palouse, Washington. He will be pursuing a masters in electrical engineering at the University of Idaho after graduation. His emphasis has been in power systems and power electronics. When not studying, Will enjoys backpacking, fly fishing, and gardening.	Electrical Engineering	 	 	
Bruno Loza 	Bruno is a senior studying electrical engineering with an emphasis in power. He was raised in southern Idaho and his hobbies include playing guitar, ultimate Frisbee, and soccer. 	Electrical Engineering	 	 	
Khalid Alotaibi	Khalid is an International student who came from Saudi Arabia. He is a senior in electrical engineering and his emphasis is power. In addition, Khalid loves to play and watch soccer. Other hobbies include volleyball, traveling, horse riding and swimming. 	Electrical Engineering	 	 	
==Documents Archive==
===System Specifications===
 
===Guides===
 
 
===Technical Presentation===
 
===Meeting Minutes===