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©Kestrel Power Engineering Ltd, 2006 K2006_23_DRAFT

IESO Compliance Tests

OPG Mtn Chute G2

K2006_23_DRAFT

PRIVATE INFORMATION Contents of this report shall not be disclosed without the consent of the Customer.

Kestrel Power Engineering, 312 Bowling Green Court

Mississauga, Ontario, Canada L4Z 2T1 Rev. Date Submitted by Comments 0 27 August 2006 Les Hajagos, P. Eng.

©Kestrel Power Engineering Ltd, 2006 K2006_23_DRAFT

IESO Compliance Tests

OPG Mtn Chute G2

K2006_23_DRAFT

Prepared by: Les Hajagos, P. Eng. Peer Review by: G. R. Bérubé , P.Eng.

DISCLAIMER Kestrel Power Engineering Ltd. takes reasonable steps to ensure that all work performed shall meet industry standards, and that all reports shall be reasonably free of errors, inaccuracies or omissions. KESTREL POWER ENGINEERING LTD. DOES NOT MAKE ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS OR IMPLIED, WITH RESPECT TO THE MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OF ANY INFORMATION CONTAINED IN THIS REPORT OR THE RESPECTIVE WORKS OR SERVICES SUPPLIED OR PERFORMED BY KESTREL POWER ENGINEERING LTD. Kestrel Power Engineering Ltd. does not accept any liability for any damages, either directly, consequentially or otherwise resulting from the use of this report. THIS REPORT IS PROTECTED BY COPYRIGHT. Any reproduction distribution or copying, either in whole or in part, without the specific written permission of Kestrel Power Engineering Ltd., is strictly prohibited.

IESO Compliance Tests OPG Mtn Chute G2

©Kestrel Power Engineering Ltd, 2006 i K2006_23_DRAFT

EXECUTIVE SUMMARY This report provides details of the tests performed on the generator, exciter, power system stabilizer and governor at Mountain Chute Unit 2 in April 2006. The tests were performed to confirm the models previously reported to the Ontario IESO and to identify and correct any latent defects in the control equipment as part of OPG’s five year re-testing program. Models have been provided, suitable for meeting compliance requirements, and this data should be submitted by OPG to the IESO for inclusion in their future simulations. The following are the main conclusions/recommendations from this report:

1. Reactive capability testing was performed on this unit and confirmed that it meets the IESO Market requirements. Updated reactive capability curves have been provided as part of this report and should be submitted by OPG to the IESO.

2. The power system stabilizer is set to meet IESO requirements and is in service above the turbine rough zone load level.

3. The excitation system meets IESO requirements for response time and positive ceiling level. 4. The negative ceiling voltage was incorrectly reported in previous references. The actual

value for this design does not meet the present IESO requirements and should be reported. This is a limitation of this particular design and no action can be taken to correct it.

5. The governor has been tuned to meet system requirements for isolated operation. 6. The governor meets IESO droop and deadband requirements. 7. The simplified generator, exciter, stabilizer and governor tests documented in the references

should be followed on a routine basis to ensure continued correct operation of this equipment. 8. The present LOE settings meet the guideline adopted by OPG. These settings should be re-

visited by OPG EP to decide whether changes are required to align them with industry-standard (IEEE) recommended settings.

9. The databank inertia value, which was confirmed from load rejection tests on unit 1, did not provide an exact match to the measured acceleration on unit 2 in two tests. The databank value was retained in the generator model and power system stabilizer digital settings, however OPG should review the rotor and turbine design to determine whether there is any reason for the different inertia values between these two units.

The Appendices to this report contain details and reference material for use by the station staff to ensure that the exciters continue to meet performance and regulatory requirements: Appendix A model, rating data and characteristic curves for generator, exciter and governor Appendix B plots of selected site measurements Appendix C settings listing (as-left) for future reference The exciter, stabilizer and governor settings documented in this report must not be changed without notifying the IESO.


©Kestrel Power Engineering Ltd, 2006 ii K2006_23_DRAFT

Table of Contents Executive Summary ....................................................................................................................... i 1 GENERATOR PARAMETERS ..............................................................................................1

1.1 Open Circuit Saturation Curve ......................................................................................................1 1.2 Combined Turbo-Generator Inertia ...............................................................................................1 1.3 Time Constants and Transient Reactances..................................................................................1 1.4 Synchronous Reactances .............................................................................................................2 1.5 Generator Capability Curves.........................................................................................................2

2 EXCITATION SYSTEM TEST RESULTS..............................................................................3 2.1 Initial Inspection.............................................................................................................................3 2.2 Power Supply Measurements .......................................................................................................4 2.3 Waveform Measurements .............................................................................................................4 2.4 Ceiling Voltages ............................................................................................................................4 2.5 Reactive Current Compensation...................................................................................................5 2.6 Field Current Limiter......................................................................................................................5

3 Power System Stabilizer........................................................................................................6 4 Governor................................................................................................................................7

4.1 Off-Line Speed Governing ............................................................................................................7 4.2 On-Line Governor Response ........................................................................................................7 4.3 Miscellaneous Measurements.......................................................................................................8

5 References ............................................................................................................................9 Appendix A: Models and Ratings..................................................................................................1

A1. Ratings................................................................................................................................................2 A2. Generator Model.................................................................................................................................3 A3. Excitation System Model ....................................................................................................................4 A4. Power System Stabilizer Model..........................................................................................................5 A5. Turbine Governor Model.....................................................................................................................6 A6. Calculated Capability Curves .............................................................................................................7 A7. Open Circuit Saturation Curve............................................................................................................8

Appendix B: Performance Measurements ....................................................................................1 B1. Partial Load Rejection.........................................................................................................................2 B1b. Partial Load Rejection.......................................................................................................................3 B2. Partial Load Rejection.........................................................................................................................4 B3. Open Circuit Voltage Regulator Step Response ................................................................................5 B4. Generator Steady State Measurements .............................................................................................6 B5. Voltage Regulator Large Signal Performance....................................................................................7 B6. Exciter Bridge Waveforms ..................................................................................................................8 B7. AVR Test Point Waveforms................................................................................................................9 B8. Gate Pulse Test Point Waveforms .....................................................................................................3 B9. AVR Firing Angle Delay ......................................................................................................................3 B10. On Line Step Response, Stabilizer Gain=1......................................................................................4 B11. On Line Step Response, Stabilizer Gain=7.5 (Final)........................................................................5 B12. On Line Step Response, Stabilizer Gain=15 (2xFinal).....................................................................6 B13. Fast Gate Limit Change....................................................................................................................7 B14. Governor Pilot Valve Jog Test..........................................................................................................8 B15. Governor Off Line Step Response ...................................................................................................8 B16. On Line Governor Response, Dashpot Bypassed ...........................................................................9 B17. On Line Governor Response, Dashpot in Service ...........................................................................9 B18. Governor Response to Ambient System Frequency Variations.....................................................10

Appendix C: Equipment Settings ..................................................................................................1 C1. Digital Power System Stabilizer Settings ...........................................................................................1 C2. Woodward Cabinet Actuator Settings ................................................................................................1


©Kestrel Power Engineering Ltd, 2006 1 K2006_23_DRAFT

1 GENERATOR PARAMETERS Confirmation of key generator parameters was made by test. Appendix A2 summarizes the recommended parameters to be used in simulating the performance of this generator. Tests to confirm relevant generator parameters are listed below. Quantities in this report are expressed in per unit or engineering units (e.g. kV, MVA). Values expressed in per-unit are divided by a base value such that they will normally range between 0 and 1 for normal operating conditions. Per unit base data summarized in Table A1 correspond to the values used in reporting the generator impedances and time constants, and used in the digital exciter to scale the input signals in per unit. 1.1 Open Circuit Saturation Curve The unit was started on local control and then switched to manual regulator to obtain steady-state measurements of field current and voltage and ac terminal voltage. Figure A7 displays the open-circuit saturation curve, along with the tangent to the lower measurements, forming the air-gap line. The base field current is determined as the intersection of the air-gap line and rated terminal voltage (i.e. 1 pu). The field winding resistance was confirmed by dividing the field voltage by the field current measurements. The resulting resistance value for unit 1 was 0.153 Ω. Based on the manufacturer’s resistance value, this corresponds to an average operating temperature of 40°C, which is reasonable for the unit’s prevailing operating conditions. The manufacturer’s base field resistance, of 0.172 Ω, calculated at a temperature of 75°C, was used to determine the base field voltage listed in Table A1. The generator saturation characteristic can be expressed in the form of coefficients S(1.0) and S(1.2) where:

FD T FD AIR GAP T

FD AIR GAP T

(I (E 1.0pu) I (E 1.0pu))S(1.0) = I (E 1.0pu)

= − ==

S(1.0) is a measured value and S(1.2) is a calculated extrapolation of the manufacturer’s curve. The measurements confirm the databank values. 1.2 Combined Turbo-Generator Inertia The value of inertia (H) was measured from a partial load rejection test shown in Figure B1. The inertia may be calculated from the initial rate-of-change of unit speed and the drop in active power. The databank inertia value was confirmed from load rejection tests on unit 1 [10]. The databank inertia value was found to predict a higher acceleration than that measured (Figure B1b), indicating that unit 2 has a slightly higher inertia. The load rejection was repeated, but with similar results (Figure B2). The databank value was retained in the generator model and power system stabilizer digital settings pending review by OPG on possible sources of the different inertia values between these two units. 1.3 Time Constants and Transient Reactances Generator d-axis transient parameters are typically confirmed from simulations of a zero power factor leading load rejection test with manual field voltage control. This excitation system does not have a manual regulator, and this test was performed on unit 1 [10]. The d-axis parameters were further confirmed by a simulation of the open circuit step response, such as the one shown in Figure B3. The simulations include the effects of temperature and frequency on the rotor resistance, field voltage and



generator transient time constant. The open circuit step response simulation using the databank generator parameters shows excellent correlation with the measured results. 1.4 Synchronous Reactances Generator d-axis and q-axis mutual reactances (Xad, Xaq), were confirmed from static measurements of field current, terminal voltage, active and reactive power, listed in Table B4. Calculations of field current for different operating conditions, using the recommended direct-axis synchronous reactance value and generator saturation representation of Appendix A2 were a good match with the measured requirements. Rotor angle measurements were also performed to confirm the quadrature-axis synchronous reactance value (Xq) listed in Appendix A2. Calculations using the databank value provided a good fit between measured and calculated rotor angles for different loading conditions. 1.5 Generator Capability Curves Calculated capability curves are shown in Figure A6. The capability curves have been confirmed based on the measured results and verified generator impedance data. The plots show the capability for rated conditions. The over-excitation limit is a function of field winding heating and the excitation system continuous rating of 1600 Adc. It must be remembered that this limit is highly dependent on terminal voltage, and therefore field current, not reactive power, should be monitored during extended over-excited operation. In the under-excited region, no attempt was made to identify the stability boundary, as the conventional assumptions are based on a unit operating with fixed field voltage. This does not apply to this unit, as it is equipped with an automatic voltage regulator and power system stabilizer. The loss of excitation (LOE) relay characteristic has been shown on the curve based on settings in reference [5]. The settings follow the normal OPG approach. These settings should be re-visited by OPG EP to decide whether changes are required to align them with industry-standard (IEEE) recommended settings [14]. These curves are provided for reference only. The official OPG curves should be used for operation of this unit. This generator is registered with the IESO based on its original nameplate rating of 75 MVA, even though its accepted apparent power capability is 86.25 MVA. The registered MCR for these units is 85.1 MW. According to convention, the units’ Rated Active Power (RAP) is 67.5 MW based on the original apparent power base and a power factor of 0.9. The unit’s reactive obligations are +32.7 MVAr and –22.2 MVAr. From the capability curves of Figure A6 it can be seen that the reactive requirements are met at all active power levels. Full load overexcited measurements were performed for a period of 65 minutes, following a lengthy period at RAP active power, until temperatures had stabilized at the values shown in Table B4. Leading reactive power output was limited by stator voltage (95%). The field current requirement for operation at RAP and 0.9 power factor and voltage is calculated to be 1103 Adc, which is well below the generator rotor and exciter capabilities. There is a limitation on main output transformer apparent power of 84.7 MVA in summer and 99 MVA in winter [11], and its conditions were monitored during full load tests.



2 EXCITATION SYSTEM TEST RESULTS Mountain Chute unit 2 is equipped with an ASEA analog static-excitation system. The excitation system was installed and commissioned in 1969. Tests were performed in 1991 to correct intermittent failures [3]. Based on this report, condition assessment tests were performed on unit 2 in April 2006 to confirm that it continues to function as commissioned [12]. The overall excitation system response continues to be good. The automatic voltage regulator (AVR) transfer function may be modeled using the IEEE standard type ST1A model [9], shown in Appendix A3. The following parameters (gains and time constants) are not applicable to this system, or are negligible, and should be set to default values (the values used are dependent on the simulation program, most programs take a zero entry as an indication that this portion of the model is not applicable): Kf = Ta = 0, Tf = 1 2.1 Initial Inspection With the unit de-energized, the electronic cards were inspected with the results listed below: QIPS113 (Voltage Measurement) Voltage level 4.2 Gain 3 This card was dusty but showed no evidence of failing components. Care must be taken not to replace this card with a spare modified for use in G1, which had an R-C network added for transient gain reduction. Should a replacement card be required, it must be modified as documented in 1997 [13]. Amp Selector The three cards in this module show no evidence of failure. There are some transistors that may be difficult to obtain replacement parts. Rotor Current Limiter Setting 71 This card uses components that will be difficult to source spare parts. The existing card shows no sign of failing components. Manual Regulator This card shows no sign of failing components. Although described as a manual regulator, this card is only used with the exciter on test supply, and not for on-line use with the automatic voltage regulator out of service. Power Supply The large electrolytic capacitors in this module look in good condition, but should be inspected regularly for signs of failure. Station staff should catalogue the available spare cards and modules including those removed from unit 1, which has had its exciter replaced.



2.2 Power Supply Measurements AVR Power Supply Measurements: +24 = 25.97 V (pin 9) ripple pk-pk = 0.06 V (pin 2 common) -24 = -27.41 V (pin 11) ripple pk-pk = 0.03 V +12 = 12.57 V (pin 3) ripple pk-pk = 0.05 V -12 = -12.68 V (pin1) ripple pk-pk = 0.05 V Control Pulse Unit Power Supply Measurements: +24 = 24.86 V (pin 10) ripple pk-pk = 0.9 V (common pin 9 position 2.22) -24 = -26.65 V (pin 14) ripple pk-pk = 2.0 V +12 = 13.3 V (pin 8) ripple pk-pk = 0.3 V -12 = -12.55 V (pin 7) ripple pk-pk = 1.2 V These results are virtually identical to those reported in 1991 [3]. 2.3 Waveform Measurements A series of multimeter and oscilloscope measurements was performed to confirm the correct operation of the thyristor bridges and various electronic inputs and outputs of the exciter. Sample measurements are shown for reference in future troubleshooting. The AVR input from the rectified PT feedback voltage signal is shown in Figure B7 for a simulated PT secondary signal of 112 Vrms. There is no evidence of problems with the terminal voltage rectifier components. The simulated PT signal was changed in a step and the transducer output was then recorded (Figure B7). The terminal voltage transducer responds after a short time constant as expected. The firing pulses were checked for each of the thyristors. Sample measurements are shown in Figure B8 for future reference. There are no signs of faulty gate pulse capacitors or other timing components. 2.4 Ceiling Voltages The simulated PT input was varied and the firing angle delay was measured. The results, shown in Table B9, match those from 1991 [3]. This corresponds to a firing angle range of 10 to 160 degrees on the thyristor bridge. The delay for each thyristor leg is also shown in the table. The waveform and delay angles match those in Figure 3 of the manufacturer’s manual. The ASEA exciter at Mountain Chute was designed and built during a period when thyristor voltage ratings were a limiting factor in this type of excitation application. As a result the designers connected an un-controlled diode bridge and a controlled thyristor bridge in series to obtain the required positive ceiling voltage. As a result the negative ceiling is very limited and does not meet present IESO requirements. The two bridges are connected to the secondary windings of the excitation transformer, ratio 13.8kV:400:220 (Y-Δ-Δ configuration), with the thyristor bridge connected to the higher secondary voltage windings. Based on the controlled bridge firing angle advance and retard limits of 10° and 160°, the theoretical no-load ceiling voltages are 828/-210 Vdc. Measurement of the ceiling voltages, beginning from reduced terminal voltage, is shown in Figure B5 and Figure B6. The measured ceiling levels of



+752/-175 V (+6.88/-1.6 pu on the field voltage base) for normal operating conditions match the theoretical levels within tolerance and are recommended for modeling purposes. The negative ceiling was incorrectly reported in previous references [4] and must be corrected in the database. The field current requirement at RAP and 0.9 power factor lagging is 1103 Adc. Based on this, the IESO required ceiling voltage is 379 Vdc, which has been met. The exciter transformer impedance is represented in the positive output limit, as it has an effect at high field current levels. The equivalent commutating drop used in the model is computed as:

KV I X

E Icrms fdbase c

fdbase rated=

1352

. * * ** *

where Xc is the leakage reactance of the transformer expressed on its own kVA base (0.07 pu), Irated is the excitation transformer’s rated current level, converted to equivalent dc current, and Vrms is the excitation transformer line-to-line secondary voltage for rated terminal conditions: Irated = 1400kVA*103 / ((620V)*(2)1/2) = 1597 Adc (The exciter nameplate rating is 1600 Adc) Kc = 0.107 pu 2.5 Reactive Current Compensation Units 1 and 2 each have a dedicated step-up transformer. Accordingly, unit 2 does not have reactive compensation, and the exciter compensator is set to 0. Absence of reactive current compensation was confirmed by performing equal (2%) terminal voltage reference step changes off line and on line, and measuring the actual terminal voltage change. 2.6 Field Current Limiter This exciter includes an over excitation limiter (OEL) based on indirect field current measurement via CTs on the exciter transformer ac supply. To test this function, a dc test source was injected at terminals 1(-)to 9(+) of the Current Limiter card. The dc level was gradually increased to the level that produced limiting. This voltage was measured at the AVR/Limiter final auctioneer output to be –9.62 V, corresponding to a rotor current of 2780 Adc. This matches measurements performed in 1996. This excitation system is also equipped with an Under-Excitation Limiter. It is not normal practice within Ontario to use these limiters on large units, especially hydroelectric units and the UEL was left disconnected, as it was found.



3 POWER SYSTEM STABILIZER This unit is equipped with an Ontario Power Technologies Digital Power System Stabilizer (DPSS). The stabilizer implements an IEEE standard type PSS2A transfer function [9], shown in Appendix A4. This stabilizer uses two measured inputs, electrical power and compensated frequency (speed) and is the standard configuration throughout North America. The parameter XQ, set equal to 0.54, is used to calculate rotor speed from the measured frequency of the voltage input signal. This setting was selected during commissioning based on measurements of the stabilizer’s internally calculated mechanical power variable [7] and was not changed during these tests. On-line step response tests for unit 1 are shown in Figure B10 to Figure B12, with the PSS enabled at gains of 1, 7.5 and 15. The appearance of a higher frequency mode in stabilizer output and field voltage established the maximum stabilizer gain. Local mode damping (1.7 Hz) is excellent at the as-left gain of 7.5 as shown at full load in Figure B11 and a higher gain is not required. It is noted that the inertia value used in the stabilizer matches the databank value and that of unit 1 (section 1.2). The load rejection measurements indicate a slightly higher inertia value, and this difference could be part of the reason that the final stabilizer gain for unit 2 is half that used on unit 1 with similar AVR gains. If a different inertia value is confirmed and the PSS settings are changed, then step response tests are recommended to re-verify the final PSS gain. The PSS is selected to automatically turn on above turbine rough zone, and turn off at a level slightly below the turn-on value to provide some hysteresis. The turn-on and turn-off levels are 50 MW and 47 MW, (0.67 pu and 0.62 pu MVA respectively). A fast power ramp was introduced through the governor to check the stabilizer response to mechanical power changes. The results shown in Figure B13 confirm that the stabilizer does not introduce unacceptable terminal voltage and reactive power transients, despite the very fast power change applied. The test plan shown in reference [7] should be used on a regular basis to confirm the continued correct performance of this stabilizer. During these tests in April 2006, a new battery was installed in the DPSS unit and the settings were saved to flash memory with the latest version of software (V4R6). The local P&C computer was also updated to the latest version of the DPSS Host program (V2R1) and was used to execute the step response tests. Extra batteries were left with P&C staff together with installation instructions (placed in the DPSS hardware manual). The as-left settings are summarized in Table C1.



4 GOVERNOR Mountain Chute unit 2 is equipped with a Woodward Cabinet Actuator mechanical-hydraulic governor. Detailed tests were performed to configure the governors for stable isolated operation and to meet new Ontario regulatory criteria. The simplified governor tests included in [8] describes tests to be carried out by local staff to configure the governor to have settings matching those described in this report, which should be performed after each major outage. The as-found and as-left settings are summarized in Table C2. 4.1 Off-Line Speed Governing The permanent droop dial was set to zero and the speed reference dial moved to various positions to check its calibration with the present governor setup. The results for different speed reference positions are tabulated below (note: 1 refers to the large hand at the 1 position and the small hand at the zero position, i.e. high noon). Each turn of the speed reference dial produced a change of just under 1% (i.e. 0.6 Hz).

Governor Speed Reference Calibration Off Line On Line Droop=4%

Speed Droop=0 Gate Active Dial Frequency Position Power

(turns) (Hz) (%) (MW) -3 57.6 -2 58.12 -1 58.74 0 59.15 17 2 1 59.7 42 34 2 60.22 64.5 60 3 60.76 91 76 4 61.25

The response to a manual change in pilot valve position is shown in Figure B14. The gate position returns smoothly to its pre-disturbance condition as desired. The response to a -1% speed reference dial change is shown in Figure B15. 4.2 On-Line Governor Response The governor droop was returned to its normal level of 4% and the unit was synchronized. The unit was loaded to various speed dial reference positions as shown in section 4.1. A 1% change in speed reference position produced an average gate position change of just under 25%. The calculated droop is 3.6%, which is within acceptable tolerance of the 4% dial setting. The permanent droop dial setting matches OPG’s standard setting and no changes are recommended to this setting. With the dashpot bypassed, unit 1 loaded/unloaded quickly as required (Figure B16). The gate rate limits (+12%/s, -22%/s) were measured from the test shown in Figure B13. The unit was placed in its damped operating mode (i.e. dashpot bypass not energized) and the response of the unit to a 1% speed reference change was measured. The as-left response for unit 2 is displayed as



Figure B17. The simulated results were obtained with the model parameters of Appendix A5. The as-left needle valve position results in a reset time of 4.5 seconds for unit 2. Optimal settings for this location were applied as summarized in Table C2. The combination of the floating lever connection point and compensating crank determine the value for the temporary droop. The timing procedure provided in [8] should be used to adjust the reset time following major outages. Following tests and analysis on both units, the target dashpot reset time was calculated to be slightly longer at 7.5 s, resulting in an on-line gate timing for 16% gate position change of 120+/-20 s. 4.3 Miscellaneous Measurements Inspection of the unit did not reveal any obvious problems with the configuration or condition of the governor. Linkages were free to move but did not appear to have any unwanted slack resulting from worn pins or connecting rods. The distance from the body of the dashpot to the connecting pin on the small dashpot plunger was verified, as this affects the speed calibration. The distance was exactly on specification (2 and 7/8”). All other checks verified that the unit was set up properly per Woodward instructions. The mechanics correctly perform and document the required procedures during each outage and keep the unit in excellent condition. The vibration on the relay valve plunger was measured to be 0.006” total indicator reading. This level is slightly below Woodward’s instructions to ensure zero effective lap. This provides the highest sensitivity and ensures that the dead band on the unit is low. A test to identify binding in the linkages was performed on the unit. With the gate position at an intermediate position with the unit on line, the pilot valve was manually depressed and allowed to return to its original position. The pilot valve was then manually lifted and released and the resulting three gate positions were compared as summarized below. A maximum difference of less than 2%, as found in this test, is considered good. Pilot Valve Jog Test

Initial gate (%) Gate (%) following jog downwards Gate (%) following jog upwards 90.5 90.5 90.5

Response of the unit to a partial load rejection are shown in Figure B1. The deadband was checked by recording the unit response to ambient system frequency variations while operating at a constant dispatch. The results shown in Figure B18 indicate that this governor is in excellent condition and is capable of responding to frequency variations of less than 10 mHz, which is well within the NERC requirement of no more than 36 mHz dead band.



5 REFERENCES 1. Generator Acceptance Test Report Mountain Chute GS, OHRD report no. 70-53-H, 3 February

1970. 2. Generator Capability Curve, Mountain Chute 1&2, JFL/EMD, Jan 1978. 3. Excitation System Tests Mountain Chute GS, OHRD report no. 91-109, May 1991. 4. Ontario Hydro Dynamic Database, January 1998. 5. LOE Relay Settings Sheet, Mountain Chute GS, 28/7/67. 6. Open Circuit Saturation Curve #121950, OHRD report no. 70-53-H, 3 February 1970. 7. Digital Power System Stabilizer, Mountain Chute Unit 2, OHT report no. AH 96-150, 13

September 1996. 8. Generator Parameter Measurements, Test plan KES2005_114, Kestrel Power Engineering

September 2005. 9. IEEE Recommended Practice for Excitation System Models for Power System Stability Studies,

IEEE Standard 421.5-2005, April 2006. 10. IESO Compliance Testing, OPG Mountain Chute G1, Kestrel Power Engineering report

K2006_22, August 2006. 11. Mountain Chute GS T1&T2 Revision to Continuous Thermal Rating of Main Output Transformer,

OPG memo, March 11, 2002. 12. Exciter/PSS Off Line Tests, Test Plan KES2006_140, Kestrel Power Engineering April 2006. 13. Mountain Chute Exciter Modules, Memo from George Schembri to Jerry Kelley, OPT 24 March

1997. 14. IEEE Guide for AC Generator Protection, IEEE Standard C37.102-1995, December 1995.


©Kestrel Power Engineering Ltd, 2006 A - 1 K2006_23_DRAFT

APPENDIX A: MODELS AND RATINGS



A1. Ratings Ratings Description Parameter Value Units Generator Base Power MBASE 75 MVA Turbine Maximum Continuous Rating MCR 85.1 MW Rated Active Power RAP 67.5 MW Generator Base Voltage BASEKV 13.8 kV Rated Speed rpm 100 rpm Power Factor pf 0.93 Rated field current ifdrated 1600 Adc Base Air-Gap Line Field Current ifdbase 636 Adc Base Air-Gap Line Field Voltage efdbase 109 Vdc Field Winding Resistance at 75C rfdbase 0.172 ohms



A2. Generator Model Generation Facilities

Network Impact Mountain Chute G2 Unit Data Type (e.g. salient pole, round rotor, induction) salient Frequency (Hz) 60 Fuel type (e.g. water, coal, oil, nuclear) HY NERC – Unit Type (see “NERC Fields – Valid Codes”) WAT NERC – Cooling Water Source(s)* WAT NERC – Fuel Type: Primary & Alternate (see “NERC Fields – Valid Codes”) WAT N/A NERC – Transportation Method (see “NERC Fields – Valid Codes”) N/A NERC – Primary fuel heat rate at full load (BTU/kWhr) N/A NERC – Status Code (see “NERC Fields – Valid Codes”) OP Rated capability (MVA) 75 Rated voltage (kV) 13.8 Power Factor 0.93 Total rotational inertia of Generator and Turbine (s) 2.77 Unsaturated reactances in pu on machine base

Xd X’d X’’d Xq X’q Xl X2 Xo 0.802 0.224 0.160 0.471 0.25 0.155 0.178 0.1 Open circuit time constants (s) T’do T’’do T’qo T’’qo 5.55 0.045 N/A 0.035 *Source(s) from which cooling water for thermal-electric plants and water for generating power for hydroelectric plants is directly obtained. Connection Unit Data Manufacturer CW Serial Number 11S1363 OCT 1967 Speed (RPM) 100 Station load (MW, Mvar) 0 0 Maximum continuous rating in summer and winter (MW) 85.1 85.1 Minimum power (MW) 0 Normal ramp rate (MW/min) 75 Emergency ramp rate (MW/min) 75 Armature resistance, Ra, in p.u. and field resistance ,Rfd*, in Ω 0.00322 0.172 Saturation at rated voltage (S1.0) and 20% above (S1.2) 0.141 0.677 Inertia constant for machine only (s) (on request) 2.635 Damping 0 Base field current (A) 636 Base field voltage (volts) 109 Losses at 1.0 and 0.9 power factor at maximum continuous rating(MW) 1.251 1.423 Characteristics Open circuit saturation curve attached Short circuit curve Attached V curves Available Capability curve Attached

*Field resistance for hydraulic units should be specified at 75ºC and at 100ºC for thermal units.



A3. Excitation System Model

ESST1A (IEEE Type ST1A Model) Description ICONS Parameter Value Alternate UEL inputs IC UEL (1,2, or 3) 1 Alternate stabilizer inputs IC+1 VOS(1 or 2) 1 Description CONs Parameter Value Units Terminal voltage transducer T.C. J Tr 0.01 s AVR upper limit J+1 VIMAX 999 pu AVR lower limit J+2 VIMIN -999 pu AVR lead time constant J+3 TC 0 s AVR lag time constant J+4 TB 0 s AVR lead time constant J+5 TC1 0 s AVR lag time constant J+6 TB1 0 s AVR gain J+7 KA 185 pu AVR time constant J+8 TA 0 s Positive regulator output limit J+9 VAMAX 999 pu Negative regulator output limit J+10 VAMIN -999 pu Positive exciter output limit (ceiling) J+11 VRMAX 6.88 pu Negative exciter output limit (ceiling) J+12 VRMIN -1.6 pu Rectifier regulation J+13 KC 0.107 pu Exciter feedback gain J+14 Kf 0 pu Exciter feedback time constant J+15 Tf (>0) 1 s Field current limiter gain J+16 KLR 0 pu Field current limiter setting J+17 ILR 0 pu

Notes: ASEA analog-electronic full static excitation system

MVc

VREF

Vf

Vs

+-+

HVGATE

VUELVt VRMAX-Kc IFD

Vt VRMIN

1 + sTC 1 + sTC1

1 + sTB11 + sTB

KA

1 + sTA

LVGATE

VOEL

EFD

s KF

1 + s TF

-

VIMIN

VIMAX

IEEE Static Excitation Model ST1A

VAMAX

VAMIN

M

M

-

+

ILR

IFD

+

-

KLR



A4. Power System Stabilizer Model

IEEE TYPE PSS2A DUAL-INPUT STABILIZER MODEL Description ICONS Parameter Value Units First stabilizer input code IC ICS1 1 First remote bus number IC+1 REMBUS1 0 First stabilizer input code IC+2 ICS2 3 Second remote bus number IC+3 REMBUS2 0 Ramp tracking filter order IC+4 M 5 Ramp tracking filter order IC+5 N 1

Description CONS Parameter Value Units Washout time constant J Tw1 (>0) 10 sec Washout time constant J+1 Tw2 10 sec Filter time constant J+2 T6 0 sec Washout time constant J+3 Tw3 (>0) 10 sec Filter time constant J+4 Tw4 0 sec Washout time constant J+5 T7 10 sec Gain J+6 KS2 (= T7/2H) 1.805 Gain J+7 KS3 1 Ramp-tracking filter time constant J+8 T8 0.5 sec Ramp-tracking filter time constant J+9 T9 (>0) 0.1 sec Stabilizer gain J+10 KS1 7.5 Phase lead time constant J+11 T1 0.09 sec Phase lag time constant J+12 T2 0.04 sec Phase lead time constant J+13 T3 0.09 sec Phase lag time constant J+14 T4 0.04 sec Output limits J+15 VSTMAX 0.2 pu Etref Output limits J+16 VSTMIN -0.06 pu Etref Generator Apparent Power MBASE 75 MVA Turbine Generator Inertia H 2.77 MW-s/MVA

Notes:

1. The first PSS input is rotor speed in p.u. (1.0 p.u. = 60 Hz), and the second input is electrical power in p.u. (1.0 p.u. = Rated MVA).

2. Gain Ks2 is based on inertia time constant (H) of 2.77 MW-s/MVA (Ks2=TW1/2H).

MSpeeds Tw1

1 + s Tw1

s Tw2

1 + s Tw2

1

1 + s T6

Powers Tw3

1 + s Tw3

s Tw4

1 + s Tw4

Ks2

1 + s T7

Ks3

+

+

(1+s T8)

(1+s T9)

N

M M

+

-

Ks11 + s T1

1 + s T21 + s T3

1 + s T4

Vstmax

Vstmin

Output

High-Pass Filters

High-Pass Filters

Ramp-Tracking Filter

Stabilizer Gain & Phase Lead Limits



A5. Turbine Governor Model

HYGOV - MECHANICAL HYDRAULIC GOVERNOR Description CONS Parameter Value Units Permanent Droop J R 0.04 Temporary Droop J+1 r 0.64 Governor Time Constant J+2 Tr (>0) 4.5 sec Filter Time Constant J+3 TF (>0) 0.6 sec Servomotor Time Constant J+4 Tg (>0) 0.2 sec Gate Velocity Limit J+5 VELM 0.12 Maximum Gate Limit J+6 GMAX 1 Minimum Gate Limit J+7 GMIN 0 Water Time Constant J+8 TW (>0) 1.6 sec Turbine Gain (1) J+9 At 1.433 Turbine Damping J+10 Dturb 0 No-Load Flow (2) J+11 qNL 0.155

Notes: 1) turbine gain defined as At = Turbine Power(@ gFL) / (gFL – gNL) 2) No-load flow set equal to speed-no-load gate (gNL) , rated flow based on full-load gate position (gFL) 3) For load rejection studies, use gate closing rate (-0.22 pu/s)



A6. Calculated Capability Curves

-100

-80

-60

-40

-20

0

20

40

60

80

0 20 40 60 80 100

0.95 pf

0.9 pf

MINIMUM EXCITER CURRENT

ROTOR LIMITEXCITER LIMITED1600 AMPS

Active Power(MW)

14.5 kV

13.8 kV

13.1 kV

LOE RELAY

In U

nder

exci

ted

R

eact

ive

Pow

er (M

VAr)

O

ut O

vere

xcite

d

GENERATOR CAPABILITY CURVEMOUNTAIN CHUTE GS UNIT 2CW-ATI-W-72-75 MVA-13.8 KV



A7. Open Circuit Saturation Curve

0

2

4

6

8

10

12

14

16

18

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 13000

400

800

1200

1600

2000

2400

2800

3200

3600

unit 2, April 2006

SYN

CH

RO

NO

US

IMPE

DAN

CE

636 A

725 A

RATED VOLTAGE13.8 KV

RATED STATORCURRENT 3140 A

510 A

121950-RD OHRD REPORT 70-53-H

OPEN CIRCUIT SATURATION

AIR-

GAP

LIN

E

FIELD CURRENT (ADC)

STAT

OR

VO

LTA

GE

(KV)

STAT

OR

CU

RR

ENT

(A)

TEST CHARACTERISTIC CURVESMOUNTAIN CHUTE GS - UNITS 1&2


©Kestrel Power Engineering Ltd, 2006 B - 1 K2006_23_DRAFT

APPENDIX B: PERFORMANCE MEASUREMENTS



B1. Partial Load Rejection

6061626364

initial slope with databank inertia

Freq

uenc

y(H

z)

-100-50

050

100150

Efg

(Vdc

)

600650700750800

Ifg (Adc

)

01020304050

Gat

e(%

)

010203040

Act

ive

P(M

W)

-101234

0 5 10 15 20

Time(seconds)

Rea

ctiv

e Q

(MV

Ar)

13.45

13.55

13.65

13.75

Term

inal

V(k

V)04/19/2006 15:23:13



B1b. Partial Load Rejection

0

10

20

30

40

50

Gat

e(%

)

0

10

20

30

40

0 2 4 6 8 10

Time (seconds)

Activ

e P

(MW

)

60

61

62

63

64


Freq

uenc

y(H

z)



B2. Partial Load Rejection

0

0.5

1.0

1.5

0 5 10 15 20

Time (seconds)

Rea

ctiv

e Q

(MVA

r)

0

4

8

12

Act

ive

P(M

W)

670685700715730745

Ifg (Adc

)

507090

110130

Efg

(Vdc

)

59.560.060.561.061.562.0


Freq

uenc

y(H

z)

13

17

21

25

Gat

e(%

)

13.45

13.50

13.55

13.60

Term

inal

V(k

V)04/19/2006 17:09:04



B3. Open Circuit Voltage Regulator Step Response

0

1

2

0 2 4 6 8 10

Time(seconds)

Test

(%)

600

650

700

750

800

850

Ifg (Adc

)

13.3

13.5

13.7

13.9

14.1

simulatedmeasured

Term

inal

V(k

V)

04/19/2006 14:13:00

-200

0

200

400

600

Efg

(Vdc

)



B4. Generator Steady State Measurements

Active Reactive Terminal Field Field Current Rotor Angle Power Power Voltage Voltage Measured Calc Measured Calc (MW) (MVAr) (kV) (Vdc) (Adc) (Adc) (degrees) (degrees) 14.8 0.8 13.55 114 736 724 4 5 14.5 -15.6 13.11 88 565 550 5 7 16.0 39.0 14.49 185 1199 1232 7 4 50.0 3.0 13.60 135 850 827 17 17 49.0 -16.0 13.15 110 690 643 23 21 51.0 37.0 14.49 190 1250 1284 12 13 75.7 3.6 13.51 159 986 924 26 25 75.0 -8.7 13.11 141 871 807 30 29 76.0 39.0 14.48 223 1388 1394 17 19

Maximum temperatures (degrees C): Stator max 95 Stator avg 91 Water cold 11 Water hot 15 Air cold 38 Air hot 52 Rotor avg 81



B5. Voltage Regulator Large Signal Performance

-5

-3

-1

1

0 1 2 3

Time(seconds)

Test

(%)

-200

0

200

400

600

800

Efg

(Vdc

)

550

650

750

850

Ifg (Adc

)

12.0

12.5

13.0

13.5

14.0

14.5

Term

inal

V(k

V)

04/19/2006 14:56:51



B6. Exciter Bridge Waveforms Steady State field voltage

Negative Ceiling

Positive ceiling



B7. AVR Test Point Waveforms AVR input rectified voltage for PT input=112Vrms

AVR output vs step change of PT input 114 to 109 Vrms



B8. Gate Pulse Test Point Waveforms 3C (w/ 20kHz pulse train) gate pulse vs C1 Control Pulse (Channel 2 = x10 scale), Leg 7

4C gate pulse vs C1 control pulse (Channel 2 = x10 scale), leg 8



B9. AVR Firing Angle Delay PT (Vrms)

Rectified AVR input at 4D:5 (Vdc)

AVR output (Vdc)

Delay angle (degrees)

116 -37.8 -9.54 161 115 -37.46 -7.79 161 114 -37.13 -5.2 135 113 -36.79 -2.607 113 112 -36.44 0 86 111 -36.12 2.63 69 110 -35.79 5.22 48 109 -35.46 7.82 13 108 -35.12 9.32 0 Gate pulse Delay

(degrees) B1 121 C1 243 D1 61 E1 304 F1 182



B10. On Line Step Response, Stabilizer Gain=1

59.9559.9759.9960.0160.03

Freq

uenc

y(H

z)

7075808590

Act

ive

P(M

W)

-505

1015

Rea

ctiv

e Q

(MVA

r)

-0.5

0.5

1.5

2.5

0 2 4 6 8 10

Time(seconds)

PSS

+Tes

t(%

)

-2000

200400600800

Efg

(Vdc

)

900950

1000105011001150

Ifg (Adc

)

13.313.413.513.613.713.8

Term

inal

V(k

V)04/20/2006 09:07:52



B11. On Line Step Response, Stabilizer Gain=7.5 (Final)

59.9459.9659.9860.0060.02

Freq

uenc

y(H

z)

-505

101520

Rea

ctiv

e Q

(MVA

r)

74

78

82

86

Act

ive

P(M

W)

-2000

200400600800

Efg

(Vdc

)

9501000105011001150

Ifg (Adc

)

-0.5

0.5

1.5

2.5

0 2 4 6 8 10

Time(seconds)

PSS

+Tes

t(%

)

13.313.413.513.613.713.8

Term

inal

V(k

V)04/20/2006 09:05:18



B12. On Line Step Response, Stabilizer Gain=15 (2xFinal)

-505

101520

Rea

ctiv

e Q

(MVA

r)

757779818385

Act

ive

P(M

W)

59.9559.9759.9960.0160.03

Freq

uenc

y(H

z)

-2000

200400600800

Efg

(Vdc

)

900950

1000105011001150

Ifg (Adc

)

-10123

0 2 4 6 8 10

Time(seconds)

PSS

+Tes

t(%

)

13.213.413.613.814.0

Term

inal

V(k

V)04/20/2006 09:09:16



B13. Fast Gate Limit Change

-2-10123

0 5 10 15 20

Time(seconds)

PSS

(%)

-100

1020

Rea

ctiv

e Q

(MV

Ar)

405060708090

simulated

Act

ive

P(M

W)

5060708090

Gat

e(%

)

800900

1000

Ifg (Adc

)

100200300

Efg

(Vdc

)

59.9559.9759.9960.01

Freq

uenc

y(H

z)

13.013.213.413.613.814.0

Term

inal

V(k

V)

04/20/2006 08:57:09



B14. Governor Pilot Valve Jog Test

14

16

18

20

0 5 10 15 20

Time (seconds)

Gat

e(%

)

59.8

59.9

60.0

60.1

60.2

Freq

uenc

y(H

z)04/19/2006 14:35:24

B15. Governor Off Line Step Response

13.0

13.5

14.0

14.5

15.0

15.5

0 4 8 12 16

Time (seconds)

Gat

e(%

)

60.1

60.2

60.3

60.4

60.5

60.6

Freq

uenc

y(H

z)

04/19/2006 14:23:53



B16. On Line Governor Response, Dashpot Bypassed

50

60

70

80

0 10 20 30 40

Time (seconds)

Act

ive

P(M

W)

60

70

80

90

Gat

e(%

)04/20/2006 09:27:30

B17. On Line Governor Response, Dashpot in Service

64

68

72

76

80

0 40 80 120

Time (seconds)

Activ

e P

(MW

)

65

70

75

80

85

90simulatedmeasured

Gat

e(%

)

04/20/2006 09:35:39



B18. Governor Response to Ambient System Frequency Variations

58

59

60

0 200 400 600 800

Time(seconds)

Activ

e P

(MW

)

64.0

64.2

64.4

64.6

64.8

65.0

Gat

e(%

)

59.97

59.98

59.99

60.00

60.01

60.02

Freq

uenc

y(H

z)04/19/2006 16:40:17


©Kestrel Power Engineering Ltd, 2006 C - 1 K2006_23_DRAFT

C1. Digital Power System Stabilizer Settings Generator Base Power Sbase 75 MVA Generator Base Voltage Ebase 13.8 kV PT ratio 120 V/V CT ratio * 1000 A/A PT scale 21.99 V/V CT scale 1.414 V/A Aux 1 scale 142.25 V/V PSS output scale 10 V/pu Etref First stabilizer input speed Second stabilizer input power Washout time constant Tw1 10 sec Washout time constant Tw2 10 sec Turbine Generator Inertia H 2.77 MW-s/MVARamp-tracking filter time constant T8 0.5 sec Ramp-tracking filter time constant T9 0.1 sec Stabilizer gain KS1 7.5 Phase lead time constant T1 0.09 sec Phase lag time constant T2 0.04 sec Phase lead time constant T3 0.09 sec Phase lag time constant T4 0.04 sec Output limits VSTMAX 0.2 pu Etref Output limits VSTMIN -0.06 pu Etref Xq compensation Xq 0.54 pu turn on level Pon 0.67 pu turn off level Poff 0.62 pu * changed April 2006 to match new CTs C2. Woodward Cabinet Actuator Settings Unit # 2 As found As left Droop dial (0-5) 4 4 Slider (1-10) 10 8 Hole (inner/outer) outer Outer Restoring ratio 47 47 Dashpot needle 1/4 1/4 Bypass needle 3/4 3/4

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