ML041050175
| ML041050175 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/01/2004 |
| From: | Warner M Florida Power & Light Energy Seabrook |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NYN-04032 | |
| Download: ML041050175 (52) | |
Text
FPL Energy Seabrook Station FPL Energy P.O. Box 300 Seabrook, NH 03874 Seabrook Station (603) 773-7000 APMl 1204 Docket No. 50-443 NYN-04032 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001
Reference:
FPL Energy Seabrook, LLC Letter NYN-04016, "License Amendment Request 04-03, Application for Stretch Power Uprate," dated March 17, 2004.
Seabrook Station Background Information to Support License Amendment Request 04-03, Application for Stretch Power Uprate To support the NRC staff's review of the referenced submittal, FPL Energy Seabrook, LLC is providing the enclosed background information., "Power Systems Energy Consulting, Seabrook Uprate System Impact Study, Phase 1 Final Report," dated January 22, 2004, provides the system impact study required by ISO-New England for the power uprate., "S. G. Whitley (ISO-New England) letter to M. R. Sorenson (FPL Energy)," dated February 11, 2004, is the ISO-New England letter to FPL Energy approving the system impact study. Enclosure 3, "M. P. Nolan (State of New Hampshire, Department of Environmental Services) letter to M. S. Ross (FPL Energy, LLC)," dated January 26, 2004, provides the New Hampshire Site Evaluation Committee's determination that it does not have jurisdiction over the proposed uprate. Note that the enclosures are being provided as information only. NRC review and approval is not required.
Should you have any questions concerning this information, please contact Mr. Stephen T. Hale, Power Uprate Project Manager, at (603) 773-7561.
Very truly yours, FPL Ene g eabrook, LLC
/ Qark E. Warner Site Vice President A1ic an FPL Group company
U. S. Nuclear Regulatory Commission NYN-04032 / Page 2 cc:
H. J. Miller, NRC Region I Administrator V. Nerses, NRC Project Manager, Project Directorate 1-2 G. T. Dentel, NRC Senior Resident Inspector Mr. Bruce Cheney, Director New Hampshire Office of Emergency Management State Office Park South 107 Pleasant Street Concord, NH 03301
Enclosure I to NYN-04032
Power Systems Energy Consulting Seabrook Uprate System Impact Study Phase 1 Final Report W.W. Price D. Chatterjee J. Martinez January 22, 2004 GEII-PSEC
Foreword This document was prepared by General Electric International, Inc. through its Power Systems Energy Consulting (PSEC) in Schenectady, NY. It is submitted to ISO New England. Technical and commercial questions and any correspondence concerning this document should be referred to:
William W. Price, PE Power Systems Energy Consulting General Electric International, Inc.
Building 2, Room 629 Schenectady, New York 12345 Phone: (518) 385-5509 Fax: (518)385-5703 E-mail: William.Priceeps.ge.com Legal Notice This report was prepared by General Electric International, Inc.'s Power Systems Energy Consulting (PSEC) as an account of work sponsored by ISO-New England. Neither ISO-New England nor PSEC, nor any person acting on behalf of either:
- 1. Makes any warranty or representation, expressed or implied, with respect to the use of any information contained in this report, or that the use of any information, apparatus, method, or process disclosed in the report may not infringe privately owned rights.
- 2. Assumes any liabilities with respect to the use of or for damage resulting from the use of any information, apparatus, method, or process disclosed in this report.
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Table of Contents EXECUTIVE SUANIARY....
5
- 1.
INTRODUCTION.....
7
- 2.
ANALYSIS APPROACH.......
................................................................................ 8 2.1 STEADY-STATE ANALYSIS APPROACH
.8 2.2 DYNAMIC ANALYSIS APPROACH
.9
- 3.
INTERCONNECTION..
4
- 4.
CASE DESCRIPTIONS.....
............................................................................................ 15 4.1 STEADY-STATE BASE CASES.16 4.2 DYNAMIC BASE CASES.20
- 5.
CONTINGENCY DESCRIPTION...............................
23 5.1 STEADY-STATE CONTINGENCIES.23 5.2 DYNAMIC CONTINGENCIES.23
- 6.
STEADY-STATE RESULTS.....................................
............. 25 6.1 PRE-EXISTING VIOLATIONS.25 6.2 PRE-CONTINGENCY VIOLATIONS.27 6.3 POST-CONTINGENCYVIOLATIONS.27 6.4 N-2 OPERABILITY ANALYSIS.30 6.5 DELTA V ANALYSIS.30
- 7.
DYNAMIC RESULTS
.31 7.1 SLTI - LIGHT LOAD WITHOUT UAE TEWKSBURY & LOWELL.31 7.2 SLT2 - LIGHT LOAD WITH HIGH NH, Low ME GENERATION.32 7.3 SLT3 - LIGHT LOAD WITH UAE TEWKSBURY & LOWELL..........................................................32 7.4 SLT4 - LIGHT LOAD WITH HIGH ME/NH AND NNE SCOBIE TRANSFER.33 7.5 SPKI -PEAK LOAD.33 7.6 SEABROOK AP FOR LINE SWITCHING.33
- 8.
CONCLUSIONS..........................................................
..........36 8.1 STEADY-STATE THERMAL AND VOLTAGE PERFORMANCE.36 8.2 DYNAMIC PERFORMANCE............................................................................................................36 8.3 OVERALL CONCLUSIONS AND RECOMMENDATIONS.37 APPENDIX A-SEABROOK SIS LOAD FLOW CONTINGENCY LIST..............................
........ 38 APPENDIX B - SEABROOK AUXILIARY SYSTEM MODEL.................................................. 42 GEll.PSEC 3
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List of Linked Files Steadv-State Thermal/Voltage Analysis Base case dispatch and reactive summary Case TI R complete NE generator list Case T4R complete NE generator list Case TILTR complete NE generator list Base case one-line diagrams Case TI - without UAE Tewksbury Case T2 - without UAE Tewksbury Case T2UQ - T2U with Seabrook Q.,,=364 MVAr Case T3 - with UAE Tewksbury Case T4 - South to North Flow Case T5 - All Newington units off Case T5sa - All Newington & Salem units off Case T5sc - All Newington & Schiller units off Case T5my - All Newington & Mystic 4,5,6 units off Case TI LT - Light Load Steady-state Contingency Definitions Steady-state Contingency Results Dynamic Analvsis Base case dispatch Base case one-line diagrams Case SLTI - without UAE Tewksbury Case SLT2x - High NH - Low ME Case SLT3 - with UAE Tewksbury Case SLT4 - South to North Flow Case SPKI - All Newington & Salem units off Case SPKI-pl - Peak Case Phase I Dynamic Analysis Results SBRK-CasesumT SBRK-TI R.
SBRK-T4R SBRK-TILTR TIR TIU TIUc T2R T2U T2Uc T2UA T3R T3U T3Uc T4R T4U T4Uc T5R T5U TSUc T5Rsa T5Usa T5Ucsa T5Rsc T5Usc T5Ucsc T5Rmy T5Umy T5Ucmy TILTR TILTU Outage Seabrook-ResultsT.xls SBRK-CasesumS-Phase 1 SLTI R SLT2R SLT3R SLT4R SPKIR SLTI-Pl SLT2-P I SLT3-Pl SLT4-PI SPKI-Pl SBRK-ResultsS-Phase 1 GEJI-PSEC 4
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Executive Summary FPLE is requesting Section 18.4 approval for an uprate of the Seabrook nuclear plant by 86 MW from the present gross rating of 1209 MW. This is the first phase a a two stage uprate: the first by 86 MW in spring 2005 and the second by an additional 19 MW in fall 2006. This report is in support of the Phase 1 uprate only. The Phase I uprate will not involve changes in the generator, excitation system, or other portions of the electrical systems of the plant. Changes are only being made to the turbine and energy supply system to increase the power output capability.
This study compared the performance of the NEPOOL system with and without the proposed Seabrook uprate for a wide range of system operating conditions and contingencies. The following assumptions were made in performing this study:
- l. The uprate will not change the generator capability curve. Therefore, the gross lagging reactive capability will be reduced from 560 MVAr lagging to 367 MVAr after the first stage uprate.
In addition, the uprate will result in the gross leading reactive capability being changed from 75 MVAr to 0 MVAr.
- 2. The uprate will not change the short circuit characteristics of the generator.
Therefore, no short circuit analysis was performed.
- 3. The uprate will not change any of the dynamic model parameters of the generator and its controls with the exception of the power limit setting on the governor model. Based on FPLE's input, these limits have been set equal to the generator maximum gross MW output plus the generator 12R losses (6 MW) at rated armature current.
Relevant queued resources for this project are Berwick, Vermont Yankee uprate, UAE Tewksbury and Lowell, Neptune DC, Second NB Tie and Orrington South Expansion,.
The Seabrook uprate is subordinate to all of these. The study included the Vermont Yankee uprate in all cases, but did not include transmission upgrades required for the VY uprate. Sensitivity cases were run with and without UAE Tewksbury and UAE Lowell.
The conclusions and recommendations from this study are as follows:
- 1. For the Phase l uprate, the generator reactive capability will be sufficient to meet both pre-contingency and post-contingency voltage criteria. The uprate has no significant adverse impact on thermal or voltage performance for the system conditions and contingencies that were studied.
- 2. The Phase I uprate has no significant adverse impact on the stability performance of the system for the conditions and contingencies that were studied, except as noted in item 3 below.
- 3. Since the output of Seabrook after the uprate may be greater than the 1200 MW loss of source limit for design contingencies, the following condition must be applied:
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The Seabrook unit, with implementation of its proposed 1,295 gross MW uprate or any lesser uprate, will be required to limit its gross output level in real-time operation such that the net loss of source that results from a contingent Seabrook generator trip is at or below the real-time-based maximum allowable net source loss for the NEPOOL control area. Any reductions to the gross output of Seabrook to meet this requirement will be required within 30 minutes of being directed to do so by ISO-NE.
- 4. No additional remedial measures are recommended for the Phase 1 uprate.
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- 1. Introduction FPLE is requesting Section 18.4 approval for an uprate of the Seabrook nuclear plant by 105 MW, in two stages, from the present gross rating of 1209 MW. The purpose of this study is to evaluate the system impacts in accordance with "NEPOOL Reliability Standards" and "NEPOOL Minimum Interconnection Standards", and to identify any necessary facility upgrades to meet these standards.
Relevant queued resources for this project are Berwick, Vermont Yankee uprate, UAE Tewksbury and Lowell, Neptune DC, Second NB Tie and Orrington South Expansion,.
The Seabrook uprate is subordinate to all of these.
The Seabrook uprate is planned in two stages, the first by 86 MW in spring 2005 and the second an additional 19 MW in fall 2006. Although a generator rewind is planned for the second stage of the uprate, the specifications and impact of that rewind are not known at present.
Therefore, it was assumed that the uprate does not change the generator capability curve or dynamic model parameters. The plant data, as supplied by FPLE, is shown in the following table:
Present 86 11W uprate 105 MW uprate Generator (gross)
MVA rating 1350 MVA 1350 MVA*
1350 MVA*
Pmax**
1209 MW 1295 MW 1314 MW Pmin 360 MW 360 MW 360 MW Qmax 560 MVAr 367 MVAr
- 309 MVAr
- Qmin
-75 MVAr 0 MVAr 0 MVAr Station Service Load P
28 MVAr 29 MVAr 29 MVAr
- Using present reactive capability curve
- Summer and winter Pmax are essentially the same.
- Qmin = 0 if a nearby 345kV line is out of service The station service load was modeled as a single static (constant impedance) load connected to the generator terminal bus for the steady-state analysis. A more detailed auxiliary load model, described in Appendix B, was used for the dynamic analysis.
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- 2. Analysis Approach Using NEPOOL study models, updated for the year 2007, this study compares the performance of the system before and after the proposed project in order to demonstrate the system impact under a prescribed set of initial conditions and contingencies established in cooperation with the NEPOOL transmission owners and ISO New England.
The study adheres to relevant sections of the "NEPOOL Planning Procedures".
The study demonstrates system performance with and without the uprate for pre-contingency and post-contingency voltages and line loading and for dynamic response to system disturbances.
The study was performed for 2007 summer extreme peak load and 2007 light load conditions based on the expected in-service data for Phase 2 of the uprate.
2.1 Steady-state Analysis Approach The steady-state analysis was performed for the full Phase 2 uprate of 105 MW with generator reactive capability limited to 309 MVAr. In instances where problems were identified, the Phase I reactive capability of 367 MVAr was also evaluated.
The thermal criteria require branch loading to be less than 100% of normal rating for pre-contingency conditions, and less than the long term emergency (LTE) rating for post-contingency conditions.
Any branch loading greater than the LTE rating requires mitigation.
Thermal criteria for N-2 testing of contingencies involving breaker failure and outages of lines sharing a common tower will consider mitigation required for any branch loading greater than the STE rating.
The pre-contingency power flow solution allows SVD's, PAR's, and LTC's to move. The post-contingency solution allows only SVD's and LTC's to move. Post-contingency swing bus power changes are reallocated to all generators in proportion to their MVA ratings to simulate inertial load pickup.
The voltage criteria are summarized in Table 2-1.
SPS Modeling The only Special Protection Schemes (SPS) modeled for the steady-state contingencies were the Y151 and 326 SPS's. In most cases, if it was likely that a contingency might activate the SPS, contingencies were run both with and without the SPS. The modeling of these SPS is as follows:
Y151 SPS - Trip the Pelham5l (71833) to G192 TAP (72715) segment of line Y151 if its loading exceeds the LTE limit.
326 SPS - Trip Newington GI and/or WF Wyman #4 if section 326 exceeds its LTE limit.
Contingencies were run tripping Newington GI only, WF Wyman #4 only, and tripping both. Other, New Brunswick generation that may be armed for this SPS were not tripped.
This SPS was only included for the T2 cases.
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Table 2-1 Voltage Performance Criteria for Power Flow Analysis.
Region kV Pre-contingency Voltage Post-contingency Voltage Criteria Criteria BHE 115kV 0.90 pu < Vbus < 1.05 pu 0.90 pu < Vbus < 1.05 pu
0.95 pu < Vbus < 1.05 pu, AV < 5%
230kV 0.98 pu<Vbus <1.05 pu 0.90 pu < Vbus < 1.05 pu, AV < I1% severe 0
- puk, 0
0.95 pu < Vbus < 1 05 pu
- 1.
.90 pu <Vbus < 1.05 pu, AV< 10%
Chester 345kV 0.97 pu < Vbus < 1.042 pu 0.97 pu < Vbus < 1.042 pu Seabrook 345kV 1.035 pu < Vbus < 1.05 pu 1.00 pu < Vbus < 1.05 pu Vt Yankee 345kV 1.00 pu < Vbus < 1.05 pu 1.00 pu < Vbus < 1.05 pu 115kV Vermont 115kV 0.95 pu < Vbus < 1.05 pu 0.92 pu < Vbus < 1.05 pu OtherNE 115kV 0.95 pu < Vbus < 1.05 pu 0.90 pu < Vbus < 1.05 pu 345kV 0.95 pu < Vbus < 1.05 pu 0.95 pu < Vbus < 1.05 pu 2.2 Dynamic Analysis Approach The criteria defining stable transmission system performance for normal contingencies (3-phase faults cleared by the slower of the two fastest protection groups or 1-phase faults with backup clearing) are as follows:
- All units must be transiently stable except for units tripped for fault clearing
- A 50% reduction in the magnitude of system oscillations must be observed over four periods of the oscillation
- A loss of source less than 1200 MW is acceptable
- Keswick GCX entry is not acceptable The criteria defining stable transmission system performance for extreme contingencies (3-phase faults with breaker failure) are as follows:
- Transiently stable with positive damping
- A loss of source less than 1400 MW is acceptable
- A loss of source between 1400 MW and 2200 MW may be acceptable depending upon a limited likelihood of occurrence and other factors
- A loss of source above 2200 MW is not acceptable GEII.PSEC 9
GEI/-PSEC 9
- A 50% reduction in the magnitude of system oscillations must be observed over four periods of the oscillation Selected bus voltages around Seabrook and in eastern Massachusetts were monitored. The generator angle, field voltage, terminal voltage, machine speed, real and reactive power output were also be monitored for all units in the area, as well as units with a power output of at least 40MW in the rest of New England. Essex voltage and Q, and Highgate voltage, P and Q were monitored. Signals pertaining to the operation of relevant SPS 'were also monitored.
The dynamic modeling, including modeling of SPS, that was used for the Vermont Yankee Uprate Study were used for this analysis. Dynamic modeling of the Seabrook generator and its excitation system used the data currently in the NEPOOL database, with the following exception:
The maximum turbine power (Pmax) in the original data was set to 0.9 p.u. of the generator MVA base or 1215 MW. For the uprate, this value was increased to 1305 MW for Phase 1. These values each represent the maximum generator output plus the 12R losses (6 MW) at rated current. Therefore, when the model is initialized at rated power output, the turbine power will be very nearly at its maximum. The unit will therefore have essentially no upward response capability for decreases in system frequency. This is consistent with the operation of the plant on "Load Limit". The unit can respond downward for increases in system frequency.
This data agrees with information supplied by FPLE and data available from the manufacturer (GE). Following established NEPOOL practice, all New England system loads were modeled as constant impedance P and constant impedance Q, except that the Seabrook auxiliary system load were modeled as described in Appendix B.
The following Special Protection Schemes (SPS) will be modeled for the stability analysis, if required:
Maxcys Over-Current SPS The purpose of this SPS is to protect the underlying 11 5kV system for loss of 345kV line 392. The Maxcys over-current SPS trips the Maxcys 345/115kV autotransformer when current flow on the Maxcys-Mason 115kV line (68) exceeds 960A (equivalent to 191 MVA at 1.0pu voltage) for 0.2 seconds.
Bucksport Over-Current SPS The purpose is to protect the underlying 115kV system for loss of 345kV lines 392 and 388. The Bucksport over-current SPS trips the Bucksport-Detroit (203) and Bucksport-Belfast (86) 115kV lines as well as the Bucksport and MIS generators when total flow on the Orrington-Bucksport (65) and Betts Rd-Bucksport (205) 115kV lines exceeds a threshold for a specified amount of time.
Specifically, this SPS begins timing if the current flow on Section 65 exceeds 678 A (135 MVA) and the current flow on Section 205 exceeds 693 A (138 MVA) simultaneously, or if the Section 65 current exceeds 960 A (191 MVA), or if the Section 205 current exceeds 960 A (191 MVA). When the timer reaches 0.2 seconds, Sections 203 and 86 and the GEJI-PSEC 10 GEII-PSEC 10
Bucksport generator are tripped. In addition, a transfer trip is started and the MIS plant is tripped after 15 cycles.
Bucksport Reverse Power SPS The purpose is to protect BHE from low voltages for loss of section 388 or 392 as well as section 396 with low internal generation. The Bucksport reverse power SPS trips the Bucksport-Orrington (65) 115kV line when the south-to-north power flow exceeds 25MW for 0.3 second and the Bucksport 115kV bus voltage has been below 0.92 pu voltage for 0.1 second. The same tripping logic is independently applied to the Bucksport-Betts Road (205) 115kV line.
Saco Valley Under Voltage Load Shed Although not an SPS, its purpose is to relieve local undervoltage problems in the vicinity of Saco Valley. This protection system trips the loads at the Saco Valley and Intervale 34.5kV buses when the Saco Valley 115kV bus voltage has been below 0.94 pu for 4 seconds.
Maine Double Circuit Tower Outage SPS The purpose of the DCT SPS is to relieve overloads on the underlying 115kV system for loss of the two 345kV lines south of Maine Yankee (375 and 377) or the Maxcys-Maine Yankee and Maine Yankee - Buxton (392 and 375) 345kV lines. The DCT SPS trips the MIS station for these two events.
Kesw'ick Loss of 3001 SPS The purpose of the Loss of L3001 SPS is to detect islanding of the Maritimes due to trips of any one of the series of 345kV connections to southern New England, i.e., line 3001 br sections 388 or 392. This SPS rejects generation in New Brunswick and/or reduces import in response to a sudden drop in power flow on the Keswick-Orrington 345kV line simultaneous with an increase in frequency at the Keswick 345kV bus. This SPS is only armed when the initial power flow on line 3001 is greater than 180MW.
The SPS begins when the power flow on Section 3001 falls below 330MW and the first timer is started. If the power flow falls below 260MW before this first timer reaches 3 seconds, then a second timer is started. If the Keswick 345kV bus frequency exceeds 60.3Hz and the second timer has not reached 1.25seconds, then generation is tripped in New Brunswick.
The amount of generation tripped approximates the initial flow on section 3001 less 200MW.
The system operator selects sufficient generation and/or HVDC imports from the list below to trip about 200 MW less than the initial flow on L3001/396.
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NB Power Generation Rejection Option List Facility Operational Choices Madawaska 350MW HVDC link Runback to 175MW or block to zero Eel River 350MW HVDC link Runback to 270,200, 160, 120, 80 or 40MW Mactaquac Hydro plant Up to four of six I 1 OMW units can be tripped Beechwood Hydro plant All three 35MW units can be tripped Coleson Cove Steam plant One of three 350MW units can be tripped Belledune One 480MW unit can be tripped Dalhousie Unit 2 (200MW) can be tripped Lingan Steam plant (NS)
One or two of four 160MW units can be tripped Keswick GCX SPS The purpose of the GCX SPS is to provide overload protection to line 3001 such that it does not trip because of a large load loss in the Maritimes when it is already running near its maximum export (from NB) capability. The GCX SPS has frequency supervision so that it will not operate for a large source loss in New England. The characteristics of the Keswick GCX relay are shown below, where the distance and angle determine the center point and the reach defines the diameter of the impedance circle.
Kes wick Zone 1, Zone 2, and GCX Relay Characteristics Zone Reach Center Distance Angle Operating Time (sec)
(pu)
I(pu)
(deg) 1 0.0440 0.0220 75 0.0 2
0.0723 0.0672 75 0.3 3
0.1060 0.0530 60 If over-frequency conditions are satisfied.
Zone I and 2 and the line protection are always armed. When the apparent impedance of line 3001 enters zone 1 or 2, it trips the line (instantaneously in zone 1 and after 0.3 sec.
in zone 2). Loss of L3001/396 causes a Northern Maine Type I SPS to operate to trip the MIS plant.
The zone 3 portion represents the GCX circle of the SPS, and is armed or blocked based upon the Keswick 345kV bus frequency. If the Keswick bus frequency exceeds 60.06Hz for more then 0.1 seconds and with a rate of change in excess of 0.lHzlsec, then the GCX relay is armed on the basis of over-frequency for 8 seconds. If the bus frequency falls below 59.94Hz for more then 0.1 seconds and with a rate of change in excess of 0.IHz/sec, then the GCX relay is blocked on the basis of under-frequency for 10 seconds.
If the apparent impedance enters the GCX circle (zone 3 of the model) and the overfrequency conditions are satisfied, the GCX sends a signal to reject some amount of pre-selected generation in New Brunswick according the rules of the Loss of 3001 SPS as described above. A 6-cycle delay is allowed between generation rejection and the instant where both the overfrequency conditions are satisfied and GCX entry occurs.
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Keswick Power Relay A different SPS called Keswvick Power Relay (KPR), is nonnally out-of-service and armed only when the Chester SVC is out of service and flows are high (i.e. > 550MW). This SPS causes runback of import from Eel River HVDC link, if the real power flow from Keswick to Orrington exceeds 650 MW and the reactive power flow exceeds 200 MVAr.
For the purposes of this study it was assumed that this SPS was out-of-service.
Chester SVC Low Voltage Blocking Function Model The dynamic modeling of the Chester SVC consists of a voltage regulating SVC (v'wscc),
which regulates to the scheduled voltage from the power flow, a power oscillation damping control (pss2a) and a supervisory low voltage blocking function. This blocking function reduces the SVC output to 0 MVAr when the Chester 345kV bus voltage is below 0.60 pu. Voltage control is restored to the SVC when the 345kV bus voltage is above 0.68 pu.
Capacitor Switching Model The shunt capacitors at five Maine 345/115kV substations (Orrington, Maxcys, Mason, South Gorham, and Surowiec) are allowed to switch during transient stability simulations.
In the power flow, these capacitor installations are modeled as SVDs with the appropriate number of banks. Specifically, three 67MVAr banks are represented at Orrington, three 50MVAr banks at Surowiec, and two 5OMVAr banks at each of the other three substations.
The generic control logic for dynamic simulations is as follows:
- If the 345kV voltage exceeds the upper voltage threshold for a specified amount of time, then a single bank is switched off.
- If the 345kV voltage falls below the lower voltage threshold for a specified amount of time, then a single bank is switched in.
- If either the ll5kV voltage or 345kV voltage exceeds the specified over-voltage thresholds, then all capacitor banks at that location are instantaneously tripped.
The specific voltage switching thresholds are shown below.
Generic Switching Logic for Maine Mechanically Switched Capacitors.
Mlaxcys Parameter Description South Corham Orrington Surowiec vmax upper voltage threshold 1.044 pu 1.043 pu vmin lower voltage threshold 0.988 pu 0.986 pu tdelay time delay before switching 4 sec 5 sec vinrg 345kV bus instantaneous overvoltage threshold 1.159 pu 1.159 pu vinlo I 5kV bus instantaneous overvoltage threshold 1.191 pu 1.191 pu GEII-PSEC 13
The control logic and values were originally derived from a combination of sources. The logic is a simplified version of the Surowiec capacitor bank control as described in an E/PRO document from 1999. The same logic and parameter values were then used for the Maxcys, Mason and South Gorham banks as well. The logic is again the same for the Orrington capacitor banks, and the parameter values were derived from the minimum and maximum voltages shown in that old power flow database as well as from the E/PRO document.
PV20 ONIS This system is designed to protect the phase angle regulators between Plattsburg and Sandbar from overcurrent. If the current at the Sandbar end exceeds 1250 amps for 5 seconds, a series reactor is inserted. If the MVA flow at the Sandbar end exceeds 274 MVA for 1O seconds the breaker at the Sandbar end is tripped.
- 3. Interconnection No changes in the existing interconnection of the Seabrook plant are included in this project. It was assumed that any changes in the generator will not significantly affect the short-circuit current available from the machine. When the designs for generator rewind for Phase 2 are finalized, this assumption should be re-evaluated.
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- 4. Case Descriptions The starting points for base case development were NEPOOL data sets in GE-PSLF format that were used for the Second NB Tie SIS. These data set were originally derived from the "2000 New England Library" summer peak and light load cases. The following updates were made to these data sets in consultation with the transmission owners and ISO-NE staff:
L. Increase NEPOOL load levels to the following 2007 levels:
Peak Load 28,384 MW (10' percentile summer peak)
Light Load 11,980 MW (45% of 5Q1 percentile peak load)
- 2. Add the following projects to the data sets:
- a. Vermont Yankee uprate, but not the transmission upgrades required for the VY uprate (capacitor and line rating increases)
- b. Mystic 8 & 9 generation
- c. Edgar/Fore River generation
- d. AES Londonderry generation
- e. UAE Lowell generation
- f. UAE Tewksbury generation
- g. Kendall 4 generation
- h. Chestnut Hill caps
- i. New Scobie autotransformer and 115kV bus reconfiguration
- j. Cross sound dc link
- k. Section G146 upgrade
- 1. New Merrimack 230/115kV transformer
- m. Series reactors on the S Agawam-N Bloomfield lines
- n. Central Mass. upgrades including Wachusetts 345kV substation
- o. Third PAR at Waltham
- p. Line rating changes, series reactors, etc. in Boston area
- q. New capacitors at Northboro Road and Millbury
- r.
Shunt reactors at Scobie (for light load case)
- s. NH seacoast changes including caps, addition of substations at Portsmouth, Brentwood, and Great Bay, second xfmr at Rochester and load estimates for 2007 peak. Note: These changes result in a significant reduction in the load supplied from the Timber Swamp 345kV bus. This results in reduced requirements for reactive power from Seabrook than would have been required using previous forecasts of this load.
Based on FPLE's request, queued resources were treated as follows:
With and without UAE Tewksbury and Lowell With Vermont Yankee uprate Without 2nd NB Tie and Orrington South Expansion GEII-PSEC 15
4.1 Steady-State Base Cases Six pre-uprate base cases were defined. The initial specifications and development are described below. A summary of the dispatches and interface flows is given in SBRK-CasesumT.xls. A summary of the reactive power output of the generating plants, shunt capacitors, and static VAr devices (SVD) is shown on the second tab of that file.
TI - Peak load without UAE Tewksbury This case was intended to represent high North-South transfer, but below the level where the 326 SPS would reject generation for critical contingencies.
NB-NE 700 MW OrSo Flow with Section 86 near maximum ME-NH 1400 MW with Wyman #4 off (lower if necessary to satisfy other transfers)
NNE-S+394 close to limit N-S close to 2600 MW with AES on, Com.-Moore off, Merrimack on (partially), and with Wyman 4 and Newington G1 out-of-service NY-NE 0MW E-V 2000 MW Cross-sound 350 MW Phase II de 2000 MW Nfld1BS all on generating PV20 140 MW Highgate 215 MW (north side of converter)
Seabrook 1209 MW gross CT Import 2000MW Boston Imp. 3600MW Due to the high load level, it was found necessary to turn Newington G I on and make the Boston Import somewhat less than specified. The North-South flow was increased to the maximum possible without exceeding the Section 326 LTE limit for loss of Section 394.
Salem generation was reduced as much as possible without overloading the Ward Hill 345/115 autotransformer.
One Schiller unit was put on due to the NH Seacoast low voltage problem (see Section 6.1.1) and Brayton Point #3 was backed off by 50 MW to compensate.
For the post-uprate case (TIU), Seabrook output was increased by 105 MW, its station service load increased by I MW and I MVAR, and its Q limits changed to +309 MVAr and 0 MVAr. The output of Newington GI was decreased by 104 MW to compensate the increased generation.
One-lines showing the NEPOOL 345kV system for cases TIR and TIU are in TI R and TI U. A complete list of the output of all the New England generators with Pmax > 25 MW is given in SBRK-TIR.
GEII-PSEC 16
T2 - Peak load mith 326 SPS armed N-S close to 3000 MW with AES on, Com.-Moore off, Merrimack on, and with Wyman 4 and Newington GI in-service.
Starting with TIR case, WF Wyman #4 was turned on. In order to keep the NNE-Scobie+394 flow below 2900 MW, RPA, SEA STRN, and WF Wyman #2 were turned off and Harris #2 was turned on. To balance the East-West flow, Brayton Point units 1 & 2 and Salem Harbor G1,G2, & G3 were taken off-line and Salem Harbor G4 and one Kendall Jet were put on-line.
For the post-uprate case (T2U), the same changes were made as for T1 U.
One-lines showing the NEPOOL 345kV system for cases T2R and T2U are in T2R and T2U.
T3 - Peak load with UAE Tewksbury and Lowell projects This case was included to show the impact of the Seabrook uprate if the UAE Tewksbury and Lowell generation projects are completed and operating.
Starting with TIR case, UAE Tewksbury and Lowell units were turned on. This was offset by turning off Mystic 8 and Salem Harbor GI, G2, & G3 and turning on Salem G4.
For the post-uprate case (T3U), the same changes were made as for TIU.
One-lines showing the NEPOOL 345kV system for cases T3R and T3U are in T3R and T3U.
T4 - Peak load with High South to North Flow This case was developed from the TI case by making the following changes:
Most of the Maine generation was taken off, including MIS, RPA, Westbrook, Bucksport, one AEC unit, WF Wyman 2, and several Western Maine hydro units.
NB-NE flow was reduced to 150 MW by reducing generation in New Brunswick.
Generation was increased South of Maine by adding Comerford, Moore, UAE Tewksbury and Lowell, Mystic 7 (with Mystic 8 and 4 off), Salem 4 (with Salem 1,2,3 off), two remaining Schiller units.
Other dispatch adjustments in Western NE to return NY-NE flow to 0.
A complete list of the output of all the New England generators with Pmax > 25 MW is given in SBRK-T4R.
For the post-uprate case (T4U), the same changes were made as for T1U.
One-lines showing the NEPOOL 345kV system for cases T4R and T4U are in T4R and T4U.
GEII-PSEC 17 GE11-PSEC 17
T5 - All Newington units off-line Starting with TIR case, Newington G1 and Con Ed Newington units were all taken off-line. The following other changes were made to compensate:
WF Wyman 1, Harris #2, and all Schiller units were turned on All Comerford and Moore units were turned on Mystic G5 and G6 were turned on NEA was turned on at 300 MW.
Salem G3 was turned off Bucksport output was reduced to 140 MW to avoid overload on S86 For the post-uprate case (T5U), the same changes were made as for TIU except that Merrimack G2 was turned down by 104 MW instead of Newington GI.
One-lines showing the NEPOOL 345kV system for cases T5R and T5U are in T5R and T5U TiLT - Light-Load Case A light load case was created with minimal flow on the Maine 345kV system to determine the impact of the Seabrook uprate on high voltages. A complete list of the output of all the New England generators with P.3 > 25 MW is given in SBRK-TI LTR.
For the post-uprate case (TILTU), the same changes were made as for TIU except that AES Londonderry was turned down by 104 MW instead of Newington GI.
One-lines showing the NEPOOL 345kV system for cases TILTR and TILTU are in T I LTR and T I LTU.
In addition to the above cases, 3 sensitivity cases, variations on the T5 case, are described below. The generation and interface flows for these cases are shown on the third tab of SBRK-CasesumT.
T5sa -All Salem units off-line Running with all Salem units off is not a secure case because the Ward Hill 345/115kV autotransformer is overloaded. However, this case was run at the request of the TWG to test whether the Seabrook uprate caused any significant degradation of thermal or voltage performance.
Starting with T5R case, Salem GI and G2 were taken off-line and four Altresco units in zone 143 (NU-MA) were put on to compensate.
For the post-uprate case (T5Usa), the same changes were made as for T5U.
One-lines showing the NEPOOL 345kV system for cases T5Rsa and T5Usa are in T5Rsa and T5Usa.
GEII-PSEC 18
T5sc -Schiller Units off-line Starting with T5R case, two Schiller units were taken off-line and four Altresco units were put on to compensate. One Schiller unit was kept on due to the pre-exiting NH Seacoast low voltage problem (see Section 6.1.1).
For the post-uprate case (T5Usc), the same changes were made as for T5U.
One-lines showing the NEPOOL 345kV system for cases T5Rsc and T5Usc are in TSRsc and T5Usc.
T5my-Mystic 4,5 & 6 off-line This case was included to represent the condition if the Mystic 4,5,6 units are not converted to the 345kV bus and thus will not run when Mystic 9 is running. Starting with the T5R case, the Mystic 4,5 & 6 units were taken off-line and Mystic G7 put on at 300 MW to compensate.
For the post-uprate case (T5Umy), the same changes were made as for T5U.
One-lines showing the NEPOOL 345kV system for cases T5Rmy and T5Umy are in T5Rmv and T5Umv.
Added Capacitor Cases To satisfy pre-contingency voltage requirements, it was found necessary to add a 50 MVAR capacitor at the Seabrook 345kV bus (see Section 6.2). Therefore, additional cases were created corresponding to each of the cases above with this capacitor added.
These cases are designated with a "c" at the end of the case id.
GEII-PSEC 1i GEII-PSEC 19
4.2 Dynamic Base Cases Five pre-uprate reference cases and corresponding post-uprate cases were specified for analysis. The specifications and development are described below. A summary of the dispatches and interface flows is given in SBRK-CasesumS-Phasel.
SLTI - Light load without UAE Tewksbury and Lowell The initial specifications for this case were as follows:
NB-NE OrSo ME-NH NNE-S+394 N-S NY-NE E-\\'
Cross-sound Phase 11 dc NfId/BS PV20 Highgate Seabrook CT Import 700 MW 1050 MW 1400 MW with Wyman #4 off (lower if necessary to satisfy other transfers) close to limit 3000 to 3400 MW with AES on, Com.-Moore off, Merrimack on, and with Wyman 4, and Newington G I out-of-service 0MW 2400 MW 350 MW 0 MW full pumping 140 MW 225 MW (north side of converter) 1209 MW gross 2000MW The pre-uprate reference case (SLTIR) was developed from the SLTIU case used in the Vermont Yankee uprate study. The total New England load was increased by about 200 MW to change from 2005 to 2007 load level and the NE to NY flow was changed from 285 to near 0. by the following generation dispatch changes:
Units taken off-line: EMI-GEN, DEXTR PF, BE 11,12, &1 OST.
Units put on-line: Brayton Point #4, Wall LV2 & 3.
For the Phase I post-uprate case (SLT-PI), Seabrook output was increased by 86 MW, its station service load increased by I MW and I MVAR, and its Q limits changed to +367 MVAr and 0 MVAr.
Merrimack 1 (120 MW) was turned off to compensate for the increased Seabrook output.
One-lines showing the NEPOOL 345kV system for cases SLTIR and SLT1U are in SLT1R and SLTI-PI.
GEII-PSEC 20
SLT2 - Light load with high NH / low ME generation The pre-uprate reference case (SLT2R) was derived from the SLT2U case used in the Vermont Yankee uprate study. The total New England load was increased by about 300 MW to change from 2005 to 2007 load level and the NE to NY flow was changed from 275 to near 0. by the following generation dispatch changes:
Units taken off-line: Shepaug, Riverside, Dexter, CRRRA, and NORHAR 1 & 2.
Units put on-line: ANP and WALL LVI.
Additional units were put on-line in Maine to increase the NNE-Scobie+394 flow to near its limit of 2520 MW.
For the Phase I post-uprate case (SLT2-P 1), the same changes were made as for SLTl-PI except that 2 AEC generators were turned off to compensate for the uprate instead of Merrimack 1.
One-lines showing the NEPOOL 345kV system for cases SLT2xR and SLT2xU are in SLT2R and SLT2-P I.
SLT3 - Light load with UAE Tewksbury and Lowell projects Starting with SLT1R case, all UAE Tewksbury and Lowell units were turned on. Mystic 7 and Montv 5 were turned off to compensate.
For the Phase I post-uprate case (SLT3-P 1), the same changes were made as for SLTI -P 1.
One-lines showing the NEPOOL 345kV system for cases SLT3R and SLT3U are in SLT3R and SLT3-PI.
SLT4 - Light load vith High ME/NH and NNE-Scobie Transfer This case was intended to show the impact of the Seabrook uprate with both the ME/NH and NNE-Scobie+394 interface flows near their limits.
Starting with SLT1R case, WF Wyman 1, 2, and 3 and RPA were put on-line. Westbrook 3 and Brayton Point 1 were taken off-line to compensate. For the Phase 1 post-uprate case (SLT4-P1), WF Wyman! & 2 (114 MW) were turn off to compensate for the uprate.
This resulted in the following transfers relative to the limits:
Interface Ref. Case Flow Uprate Case Flow Limit ME/NH 1507 MW 1413 MW 1500 MW NNE-Scobie + 394 2364 MW 2367 MW 2385 MW One-lines showing the NEPOOL 345kV system for cases SLT4R and SLT4-PI are in SLT4R and SLT4-PI.
GEII-PSEC 21
SPKI - Peak load without UAE Tewksbury and Lowell The initial specificatic NB-NE OrSo ME-NH NNE-S+394 N-S NY-NE E-W Cross-sound Phase 1I dc Nfld/BS PV20 Highgate Seabrook CT Import Boston Imp.
rns for this case were as follows:
700 MW Flow with Section 86 near maximum 1400 MW with Wyman #4 off (lower if necessary to satisfy other transfers) close to limit close to 2600 MW with AES on, Com.-Moore off, Merrimack on (partially), and with Wyman 4 and Newington GI out-of-service O MW 2000 MW 350 MW 2000 MW all on generating 140 MW 215 MW (north side of converter) 1209 MW gross 2000MW 3600MW The pre-uprate reference case (SPKIR) was developed from the SPK2U case used in the Vermont Yankee uprate study. The total New England load was increased by about 300 MW to change from 2005 to 2007 load level by the following generation dispatch changes:
Units taken off-line: Champ G2, Moore GI & G2, Schiller 4 & S.
Units put on-line: Taunton G9, Brayton Point #1, Montv #5, and WALL LV1.
For the post-uprate case (SPKI-PI), the same changes were made as for case SLT1-P 1.
One-lines showing the NEPOOL 345kV system for cases SPKIR and SPK1-PI are in SPKIR and SPKI-Pl.
GEII-PSEC 22
- 5. Contingency Description 5.1 Steady-State Contingencies The steady-state contingency list is shown in Appendix A. A complete definition of the switching actions for each contingency can be found in the file Outage.pdf. Most of these contingencies were run for each case, except as follows:
- 1. The "Light Load Contingencies" were used only for case TILT and only those contingencies were used for this case.
- 2. Contingencies 9, 10, 11, 45, 46, and 47, with the 326 SPS, were run only for Case T2.
5.2 Dynamic Contingencies The following dynamic contingencies were analyzed for some or all of the base cases:
Normally cleared Three-Phase Faults:
nc307 Newington-Deerfield 345kV nc326 Scobie-Sandy Pond 345kV nc337 Tewksbury-Sandy Pond 345kV nc343 Sandy Pond-Millbury 345kV nc363 Seabrook-Scobie 345kV nc369 Seabrook-Newington 345kV nc379 Scobie-Vermont Yankee 345kV nc385 Buxton-Deerfield 345kV nc391 Buxton-Scobie 345kV nc394 Seabrook-Tewksbury 345kV nc396*
Orrington-Keswick 345kV - Transfer trip MIS Tripping Events:
ph2 Phase 1I HVDC Single Phase-to-Ground Faults with Stuck Breaker:
sc374 Buxton 386-4 sb sc381*
VT Yankee 381 sb sc391 Buxton K391/386 sb sc394 Seabrook 294 sb Three Phase-to-Ground Faults wit ec312*
Northfield 3T sb ec326*
Scobie 9126 sb ec328*
Sherman Rd 142 sb cc368*
Card 2T sb ec374 Buxton 386-4 sb ec391 Buxton K391/386 sb ec394*
Seabrook 294 sb ec394bus Seabrook 941 sb fault on Buxton-Surowiec 345kV fault on VT Yankee-Northfield 345kV fault on Buxton-Scobie 345kV fault on Seabrook-Tewksbury 345kV th Stuck Breaker:
fault on Northfield-Alps 345kV fault on Scobie-Sandy Pond 345kV fault on Sherman Rd.-W. Farnum 345kV fault on Card-Manchester 345kV fault on Buxton-Surowiec 345kV fault on Buxton-Scobie 345kV fault on Seabrook-Tewksbury 345kV fault on Seabrook 345kV bus #1 GEII-PSEC 23
ec8x VY381 fault on VY autotransformer Added by NSTAR:
mslOl normally cleared fault on Mystic-Kingston 345kV ms302 Mystic 105 sb fault on Mystic-Cambridge 345kV mslstk Mystic 102 sb fault on Mystic-Kingston 345kV GEII-PSEC 24 GEII-PSEC 24
- 6. Steady-State Results Voltage violations and LTE overloads for all of the cases are tabulated in the file Seabrook-ResultsT.xls. Three tabs are included for each case:
- 1. VVs - Voltage violations; solution failures are also noted on this tab
- 2. LTE OL's - Line loading relative to LTE limit
- 3. Gens - Reactive output of Seabrook for each contingency Three sets of results are shown on each tab:
- 1. Reference (R) case without the uprate
- 2. Uprate (U) case
In the Overload tabs, a column is also included showing the loading difference in percent between the UC and R cases.
Entries appear in the violations tables only if one or more of the cases showed a violation for that contingency.
6.1 Pre-existing Violations Several violations existing in the pre-uprate reference cases are discussed in this section.
Generally, these are local problems which are unaffected by the Seabrook uprate.
6.1.1 NH Seacoast Voltage Violations When the new 2007 load estimates for the NH seacoast area were added to the cases, low voltages were observed for several contingencies, most notably for the Deerfield stuck breaker 851, which trips the Deerfield 345/115 autotransformer, as well as Section 385 to Buxton. This causes much of the flow to the NH seacoast area to be diverted through the S. Gorham transformer and the southern Maine/NH 115kV system. Section 250 from Louden to the Biddeford tap is severely overloaded (122% of LTE) and voltages on 17 southern Maine and NH 115kV buses are below 0.95 pu, as low as 0.932. Since a very significant decrease in ME/NH flow would be required to mitigate this condition, it was decided a more reasonable solution for this study would be to run one Schiller unit. This corrects all of the low voltages although there is still some overload on Section 250. This solution was applied to cases TI, T2, T3, and T5sc. The other cases already had Schiller units running so they were not modified.
6.1.2 Section E131 -Bear Swamp to E131 Tap This short line section is overloaded for most of the pre-contingency cases by 1 to 4 %.
Since the LTE and normal ratings are equal, it is also overloaded for most of the contingencies.
It is listed in the table only for contingencies where the OL was significantly worse than the pre-contingency value. Seabrook does not have a significant adverse impact on this OL for any contingency. It was noted in cases T5sa and T5sc that running the Altresco units unloads this line.
GEII-PSEC 25 GEII-PSEC 25
6.1.3 Section J136S - Pratts Junction to Litchfield Tap (and Pl42N)
This line section shows significant overloading for loss of Section 340, loss of 340 & 379, and loss of the VY auto. It shows small overloads for many of the other contingencies.
The Seabrook uprate has only a small affect on these overloads.
For clarity, the contingencies with only small overloads were deleted from the table.
Also, section P142N from Wachusetts to Sterling to Pratts Junction is overloaded by about 15% for Sandy Pond SB 314.
6.1.4 Contingency 108 (517-532N&S) non-solution This contingency did not solve for any of the cases. A transformer feeding a 23kV load at Field 1 is tripped forcing the load to be supplied by a high impedance line from Field 2.
This causes very low voltage at the load bus and non-solution. Since this contingency is very unlikely to be influenced by Seabrook, no fix was attempted.
6.1.5 Section 83C - SDW SOMS to S83C Tap for Light Load Case This line is overloaded pre-contingency by excessive outlet power from the Warren generating units with the Warren load reduced. The LTE limit equals the normal limit, so the overload appears for all contingencies as well. The contingency entries have been removed from the results table.
6.1.6 Coolidge, NV. Rutland low voltages In all cases, the loss of Section 340 causes low voltages at the Coolidge and W. Rutland 345kV buses. The Seabrook uprate does not have any significant adverse impact.
6.1.7 Tewksbury 115kV Contingency low voltages In all cases, several contingencies (121, 131, 132) in the Tewksbury I l5kV area cause low voltages on nearby I 15kV buses. The Seabrook uprate does not have any significant adverse impact.
GEII-PSEC 26
6.2 Pre-contingency Violations A system-operating requirement is that the voltage at the Seabrook 345kV bus be able to be maintained at 357 kV (1.035 pu) pre-contingency. The reduction in the Seabrook maximum reactive power output to 309 MVAr for Phase 2 does not permit this voltage level to be maintained in any of the peak load cases, except T4U. The generator reactive capability required maintaining 1.035 pu voltage for each of the peak load base cases was determined to be as follows:
Case Qrax (MVAr)
TIU 340 T2U 364 (One-line in T2UO)
T3U 330 T4U 285 TSU 345 For case T2U, which required the highest reactive output, it was also determined that a 50 MIVAr capacitor at the 345kV bus would hold the voltage at 1.035 pu. (See T2UC)
(One-line diagrams for the other peak-load uprate cases with a 50 MVAr capacitor are given in TlUc, Mc, T4Uc, Mc, T5Ucsa, T5Ucsc, and T5Ucmv.) Therefore, if the generator reactive capability cannot be increased to at least 364 MVAr, e.g. by a generator rewind, a 50 MVAr capacitor will be required to maintain the desired pre-contingency voltage.
The Seabrook uprate does not have a significant adverse impact on any other pre-contingency line loadings or voltages.
Since the Phase 1 reactive capability of the generator is expected to be 367 MVAr, the added capacitor will not be needed until Phase 2 of the uprate.
6.3 Post-Contingency Violations 6.3.1 TI - Peak load without UAE Tewksbury Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads - Line overloads occur for several of the contingencies for both the reference and uprate cases. The Seabrook uprate causes no significant increase (< 0.3%) in the line overloads for any of the contingencies.
6.3.2 T2 - Peak load without UAE Tewksbury; VF Wyman #4 ON-LINE Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads - Line overloads occur for several of the contingencies for both the reference and uprate cases. The Seabrook uprate causes no significant increase (< 0.3%) in the line overloads for any of the contingencies, except for the Deerfield SB 785 contingency, which causes a 0.7% increase in the loading on Section 250 (Louden to S250A tap).
GEIt-PSEC 27
63.3 T3 - Peak load WITH UAE Tewksbury Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads - Line overloads occur for several of the contingencies for both the reference and uprate cases. The only line showing a significant (> 0.3%) increase in overload with the uprate is the line between UAE Tewksbury and Tewksbury 345kV. This is due to increased reactive power flow from UAE Tewksbury.
This result indicates that the specified line rating is insufficient for the output of the UAE Tewksbury plant. The line rating should be checked. This overload should not be attributed to the Seabrook uprate.
6.3.4 T4 - Peak load with South to North Flow Voltage Violations - Aside from those discussed in Section 6.1.6 and 6.1.7, the only contingency that causes voltage violations is the Buxton Stuck Breaker K386-4. Low voltages occur on many 115kV buses in the area for both the reference and uprate cases.
The Seabrook uprate causes no adverse impact on these violations.
Overloads - Line overloads occur for several of the contingencies for both the reference and uprate cases. The Seabrook uprate causes no significant increase (< 0.3%) in the line overloads for any of the contingencies, except for the Deerfield SB 785 contingency, which causes a 0.5% increase in the loading on Scobie 2 to 2A 11kV line.
6.3.5 T5 - Peak load w ith all Newington units off-line Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads - Line overloads occur for several of the contingencies for both the reference and uprate cases. The Seabrook uprate causes increases in overloading greater then I% on the following lines:
Section 250 (Louden to S250A Tap) for cont. 50 & 66 Wakefield lines to S145 tap and T146 tap for cont. 135 Section C155N (Ward Hill to King St. tap) for cont. 123 & 124 Section P142N (Wachusetts to Pratt J) for cont. 33 Section J136S (Pratt J to Litchfield St. tap) for several contingencies All of these overloads are pre-existing conditions in the reference case that are made slightly worse, mostly less that 1.5%. The maximum increase in overload for any of these was 2.5% for Section 250. Planned system changes at Buxton and Deerfield will alleviate this pre-existing overload. The overloads in the Pratts Junction area are related to the new Wachusetts 345kV substation. Since this is one of the first studies to include this system modification, some loading limit upgrades may have been omitted.
Unsolved contingencies - Contingency 139 (Loss of Mystic 8) did not solve for the TSU case but did solve for the T5Uc case with the 50 MVAr capacitor.
GEII-PSEC 28 GE11-PSEC 28
6.3.6 T5sa - Peak load with all Newington and Salem Harbor units off-line Voltage Violations - There are a few contingencies with voltage violations for both the reference and uprate cases.
These contingencies are primarily 115kV stuck breaker contingencies at Ward Hill. There is no significant difference (0.002 pu or less) between the reference case and the uprate case Overloads - Line overload results are very similar to the T5 case with, in some cases, slightly more severe overloads for both the reference and uprate cases.
Unsolved contingencies - Contingency 44 (Tewksbury SB 3894 with Y151 SPS) did not solve for the T5Rsa, T5Usa, orTSUCsa case. Contingency 139 (Loss of Mystic 8) did not solve for the T5Usa or the T5UCsa cases. Additional reactive support is required to solve this case.
Putting the smallest Salem Harbor unit on-line permits solution with the 50 MVAr capacitor at Seabrook.
6.3.7 T5sc - Peak load with all Newington and Schilling units off-line Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads -
Line overload results are very similar to the T5 case with, in some cases, slightly more severe overloads for both the reference and uprate cases.
Unsolved contingencies - Contingency 139 (Loss of Mystic 8) did not solve for the T5Usc case but did solve for the T5UCsc case with the 50 MVAr capacitor.
6.3.8 T5my-Peak load with all Newington and Mystic 4,5,6 units off-line Voltage Violations - There are no voltage violations for either the reference or uprate case, except for those discussed in Section 6.1.6 and 6.1.7.
Overloads - Line overload results are almost identical to the T5 case.
6.3.9 TILT - Light load with minimal flow on Mlaine 345kV Voltage Violations - There are no voltage violations for either the reference or uprate cases.
Overloads - There are no overloads for either the reference case or uprate case, except the pre-existing overload discussed in Section 6.1.5 GEII-PSEC 29
6.4 N-2 Operability Analysis The only significant N-2 cases are where one of the 345kV lines in the North-South interface is out of service and one of the other lines trips. The various combinations of these line outages were analyzed using the T2U case, since this case has the highest loading on the North-South interface lines.
The only case that required generation runback to relieve overloading was for outage of both Section 394 (Seabrook to Tewksbury) and Section 326 (Scobie to Sandy Pond).
Generation runback of less than 600 MW, e.g. by tripping Westbrook units, was sufficient to relieve the overload on Section 381 (Vermont Yankee to Northfield).
6.5 Delta V Analysis The voltage change due to switching a 50 MVAr capacitor at Seabrook 345kV was calculated using the T5UC case (all Newington generation off-line). Voltage changes at nearby 345kV buses are shown below for all lines in and with Section 394 (Seabrook-Ward Hill-Tewksbury 345kV) out.
Maxcys 0.1 0.2 ME Yankee 0.1 0.2 Buxton 0.1 0.3 Surowiec 0.1 0.3 S.Gorham 0.1 0.3 Deerfield 0.1 0.6 Newington 0.2 0.8 Timber Swamp 0.4 0.9 Seabrook 0.3 0.9 Scobie 0.2 0.4 Ward Hill 0.2 out Tewksbury 0.1 0.1 Lawrence 0.2 0.4 Sandy Pond 0.1 0.2 Amherst 0.2 0.4 VT Yankee 0
0.2 GEII-PSEC 30
- 7. Dynamic Results A summary of the results for all of the contingencies and cases is shown in the spreadsheet "SBRK-ResultsS-Phasel.xls".
Each tab includes results for a pair of cases: with and without the Seabrook uprate. The plots for each case are hyperlinked to the "fault id".
The columns of the tables indicate times of operation of SPS and relays, loss of source (LOS), generator instability, oscillation damping, etc. In addition, for the ec394 and ec394bus faults, the value of Vaux 20- is recorded. This is the value of the Seabrook 13.8kV auxiliary bus voltage which the post-fault voltage dip goes below for 20 cycles. If this value is less than 0.652, it is likely the plant would trip due to tripping of the reactor coolant pumps.
7.1 SLT1 - Light load without UAE Tewksbury & Lowell The results of this case and its corresponding reference case are shown on tab SLT1 in "SBRK-ResultsS-Phasel.xls". The results for this case are essentially the same with and without the Phase I uprate, except as follows:
nc337 - Tewksbury-Sandy Pond 345kV Fault - This case results in GCX zone 3 operation for the uprate case but not the reference case.
GCX zone 3 operation is unacceptable for a normal contingency.
However, this appears to be only indirectly related to the Seabrook uprate and more directly related to the higher NNE-Scobie+394 interface flow for the uprate case. See discussion of this contingency in Section 8.2.
ec394 - Seabrook 294 Stuck Breaker - The uprate case results in operation of the GCX zone 3, which did not happen in the reference case. Loss of source is only the 600 MW of NB generation rejection. This is acceptable for an extreme contingency.
ms302 - Mystic 105 Stuck Breaker - The results are similar for the pre-and post-uprate cases, except that the Harris #1, Bucksport G4, and Champion G3 generators lose synchronism for the uprate case. The synchronous motors at Champion lose synchronism for both cases. Loss of source for the uprate case is 1330 MW, which is acceptable for an extreme contingency.
The following result was also noted:
Both the pre-and post-uprate cases result in a Maine - New Hampshire split for contingencies ec374 and ec391. The tripping of lines between Maine and New Hampshire is not explicitly modeled, but is inferred from the coherent loss of synchronism of all major generators in Maine and the Maritimes with respect to the rest of the eastern interconnection.
The resulting loss of source to the interconnection is the initial ME/NH interface flow 1211 MW or 1226 MW, which is within acceptable limits for extreme contingencies.
GEI-PSEC 31
7.2 SLT2 - Light Load with High NH, Low ME generation The results of this case and its corresponding reference case are shown on tab SLT2 in "SBRK-ResultsS-Phasel.xls". The results for this case are essentially the same with and without the Seabrook uprate, except as follows:
ec394 - Seabrook 294 Stuck Breaker - The voltage dip for the Seabrook auxiliary bus voltage is the lowest of any case for the SLT2-PI uprate case and is lower than the pre-uprate reference case. However, the Vaux 20- value for this case of 0.72 has a reasonable margin to the trip value of 0.652.
7.3 SLT3 - Light Load with UAE Tewksbury & Lowell The results of this case and its corresponding reference case are shown on tab SLT3 in "SBRK-ResultsS-Phasel.xls". The results for this case are essentially the same with and without the Phase I uprate, except as follows:
ec394 - Seabrook 294 Stuck Breaker - The uprate case results in operation of the GCX zone 3, which did not happen in the reference case. Loss of source is only the 600 MW of NB generation rejection. This is acceptable for an extreme contingency.
The following points are also noted:
- 1. For the nc337 contingency, this case results in GCX zone 3 operation for both the pre-uprate reference case and the uprate case. See discussion of this contingency in Section 8.2.
- 2. For the ms3O2 contingency, this case results only in GCX zone 3 operation for both the reference case and the uprate case.
- 3. Both the pre-and post-uprate cases result in a Maine - New Hampshire split for contingencies ec374 and ec391. The resulting loss of source to the interconnection is the initial ME/NH interface flow 1211 MW or 1226 MW, which is within acceptable limits for extreme contingencies.
GEII-PSEC 32 GEII-PSEC 32
7.4 SLT4 - Light Load Nvith High MEINH and NNE Scobie Transfer The results of this case and its corresponding reference case are shown on tab SLT4 in "SBRK-ResultsS-Phasel.xls". The results for this case are essentially the same with and without the Seabrook uprate, except as follows:
cc312 - Northfield 3T stuck breaker for fault on Northfield-Alps 345kV - This case has negative damping (growing oscillations) for the reference case. The uprate case has slightly positive damping leading to system instability. Both cases have unacceptable damping, but since the uprate case is better than the pre-uprate reference case, no adverse effect can be attributed to the Seabrook uprate.
The following points are also noted:
- 1. For the nc337 contingency, this case results in GCX zone 3 operation for both the pre-uprate reference case and the uprate case. See discussion of this contingency in Section 8.2.
- 2. For the ms302 contingency, this case results operation of the Loss of 3001 SPS for both the reference case and the uprate case.
- 3. Both the pre-and post-uprate cases result in a Maine - New Hampshire split for contingencies ec326, cc374 and ec391.
The resulting loss of source to the interconnection is the initial ME/NH interface flow 1507 MW or 1413 MW forthe reference and uprate cases, respectively.
These values are higher than the acceptable limits for extreme contingencies, but are worse for the pre-uprate than post-uprate condition.
- 4. Several other extreme contingencies resulted in GCX zone 3 operation for both the pre-uprate and post-uprate cases.
7.5 SPK1 - Peak Load The results of this case and its corresponding reference case are shown on tab SPKI in "SBRK-ResultsS-Phasel.xls". The results for this case are essentially the same with and without the Seabrook uprate. There are no criteria violations. Both the pre-uprate and pos-uprate cases result in a Maine - New Hampshire split for contingencies ec374 and ec391.
7.6 Seabrook AP for Line Switching AP is the sudden change in generator power output resulting from line switching; it is measured in per unit of the machine MVA rating. A AP analysis was performed on the light load case with high levels of Newington generation, because the highest levels of line flow near the Seabrook plant were observed under this condition. The intent was to calculate the highest AP under relatively stressed conditions, but within the existing transfer capability of the system. Stability simulations of line trip and reclose events were performed for each of the 345kV lines connected to Seabrook. None of the lines are equipped with automatic high speed reclosing, so the reclose event occurred 1O seconds after the trip. No faults were associated with any of the line trip and reclose events.
GEII-PSEC 33
The APs observed on the Seabrook unit with all lines in service, both with and without the uprate, are shown in Table 7-2. Values are shown in both MW and pu of machine MVA base.
Table 7-2 AP for Light Load Conditions (slt2) with All Lines In-Service.
(on 1350M VA)
Trip Section 369 (Seabrook-Newington 345kV) 64 0.047 58 0.043 Reclose Section 369 (Seabrook-Newington 345kV)
-95
-0.070
-87
-0.064 Trip Section 394 (Seabrook-Tewksbury 345kV)
-196
-0.145
-205
-0.152 Reclose Section 394 (Seabrook-Tewksbury 345kV) 256 0.190 271 0.201 Trip Section 363 (Seabrook-Scobie 345kV)
-134
-0.099
-141
-0.104 Reclose Section 363 (Seabrook-Scobie 345kV) 144 0.107 151 0.112 An additional AP analysis under line out conditions was also performed. Power flows were developed with either Section 394 (Seabrook-TeWvksbury 345kV) or Section 326 (Scobie-Sandy Pond 345kV) out of service for the light load study conditions. The lineout power flows were solved with all SVDs, LTC's, and PAR's active. No system redispatch was implemented.
The changes in power observed on the Seabrook unit with either Section 394 or 326 out of service, both with and without the uprate, are shown in Table 7-3. Values are shown in both MW and pu of machine MVA base.
Table 7-3 AP for Light Load Conditions (slt2) with One Line Out of Service.
l I
Existing I
Uprate Switching Action MW Pu MW pu I (on 1350MVA) 1 (on 1350MVA)
Section 394 Seabrook-Tewksbury Out:
Trip Section 369 (Seabrook-Newington 345kV) 2 0.001 I
0.001 Reclose Section 369 (Seabrook-Newington 345kV)
-2
-0.070
-2
-0.070 Trip Section 363 (Seabrook-Scobie 345kV)
-382
-0,283
-385
-0.286 Reclose Section 363 (Seabrook-Scobie 345kV) 478 0354 478 0.354 Section 326 Scobie -Sandy Pond Out:
Trip Section 369 (Seabrook-Newington 345kV) 93 0.069 87 0.064 Reclose Section 369 (Seabrook-Newington 345kV)
-143
-0.106
-133
-0.099 Trip Section 394 (Seabrook-Tewksbury 345kV)
-358
-0.265
-342
-0.253 Reclose Section 394 (Seabrook-Tewksbury 345kV) 531 0.393 578 0.428 Trip Section 363 (Seabrook-Scobie 345kV)
-74
-0.055
-81
-0.060 Reclose Section 363 (Seabrook-Scobie 345kV) 80 0.059 87 0.064 GEII-PSEC
-34 GEII-PSEC
- 34
The highest AP observed for the uprate with all lines in service was 0.2 pu in response to reclosing Section 394 (Seabrook-Tewksbury 345kV). The highest AP observed for the uprate with a line out of service was 0.354 pu in response to reclosing Section 363 (Seabrook-Scobie 345kV) with Section 394 out.
With Section 394 out and no system redispatch, loss of Section 363 caused Seabrook and Newington units to loose synchronism with uprate. Following this, instead of the SLT2U uprate case, SLT2Un was used with Section 394 was taken out of service. The resulting delta P was comparable to the reference case.
Also, with Section 326 out and no system redispatch, loss of Section 394 (Seabrook-Tewksbury 345kV) caused Seabrook and other units to loose synchronism both with and without uprate. Therefore a redispatch was performed for this line out condition. NNE-Scobie+394 flow was reduced by turning on Somerset units, a total of 174MW and reducing Newington G3 output by corresponding amount. Following this, there were no unstable units for the pre-uprate condition.
Doing the same for the uprate case still caused Seabrook and other units to loose synchronism. Hence, a new re-dispatch was performed using the uprate case. A net increase of Brayton Point generation by 392 MW's was redispatched against Newington.
The resulting delta P was comparable to the reference case.
The level of delta P transients experienced with the uprate is more in some cases and less in other cases compared with the pre-uprate system. Overall, there does not seem to be any significant difference.
GEJI-PSEC 35 GEII-PSEC 35
- 8. Conclusions 8.1 Steady-state Thermal and Voltage Performance
- 1. A total of at least 364 MVAr of generator reactive capability is needed to maintain the Seabrook 345kV voltage at a level of 1.035 pu in the pre-contingency state for the peak load level and dispatches analyzed. As long as the Seabrook reactive capability after the Phase I uprate is more than 364 MVAr, as currently expected, shunt capacitance does not need to be added at this phase.
- 2. With this level of reactive capability at Seabrook, there is no significant degradation of post-contingency voltage for any of the load levels, dispatches, and contingencies that were analyzed.
- 3. Nearly all of the overloads recorded were pre-existing conditions. The Seabrook uprate caused no more than 1% increase in these overloads, except for the following instances for the cases with no Newington units on-line (T5, T5SA, T5SC, and T5MY):
Section 250 (Louden to S250A Tap) for contingencies 50 & 66 Wakefield lines to S145 tap and T146 tap for contingency 135 Section C155N (Ward Hill to King St. tap) for contingencies 123 & 124 Section P142N (Wachusetts to Pratt J) for contingency 33 Section J136S (Pratt J to Litchfield St. tap) for several contingencies The maximum increase in overload for any of these was 2.5% for Section 250.
Planned system changes at Buxton and Deerfield will alleviate the Section 250 overloads.
- 4. With all Newington and Salem units off-line, the loss of Mystic resulted in non-solution. Having all Salem units off-line is known to produce insecure operating conditions. Putting the smallest Salem unit on-line permitted solution of this case without any violations.
- 5. Less than 600 MW of generation runback is required for the worst N-2 contingency that was analyzed. This is less than the 1200MW limit.
8.2 Dynamic Performance
- 1. The only instance where the Seabrook uprate showed a potentially-unacceptable degradation in performance was for the nc337 contingency (Tewksbury-Sandy Pond 345kV fault) for the SLTI dispatch. GCX zone 3 operation was detected for the uprate case but not for the pre-uprate reference case. For dispatches SLT3 and SLT4, both the reference and uprate cases resulted in GCX zone 3 operation.
Viewing the GCX relay plots for this contingency, it is clear that the apparent impedance trajectory approaches very near to the zone 3 locus for all cases.
Whether it enters or not is due to small differences in the cases. For the SLT1 dispatch, the uprate case had higher NNE-Scobie+394 interface flow than the reference case, which is known to have an impact on the GCX trajectory.
Therefore, it is reasonable to conclude that the Seabrook uprate has no significant impact on the performance for this contingency.
- 2. No other unacceptable adverse impact of the Seabrook Phase 1 uprate on dynamic performance was detected for the system conditions and contingencies that were studied.
GEII-SEC 3
GEII-PSEC 36
- 3. Since the output of Seabrook after the uprate may be greater than the 1200 MW loss of source limit for design contingencies, the following condition must be applied:
The Seabrook unit, with implementation of its proposed 1,295 gross MW uprate or any lesser uprate, will be required to limit its gross output level in real-time operation such that the net loss of source that results from a contingent Seabrook generator trip is at or below the real-time-based maximum allowable net source loss for the NEPOOL control area. Any reductions to the gross output of Seabrook to meet this requirement will be required within 30 minutes of being directed to do so by ISO-NE.
8.3 Overall Conclusions and Recommendations The steady-state and dynamic performance of the Seabrook Phase I uprate are acceptable as studied without any required remedial measures, except as noted in item 3 above.
GEII-PSEC 37 GEII-PSEC 37
Appendix A Seabrook SIS Load Flow Contingency List New England 345kV lines I "Loss of Sandy Pond to Lawrence 345 (326)"
2 "Loss of Sandy Pond to Lawrence 345 (326) with Y151 SPS" 3 "Loss of Sandy Pond to Tewksbury 345 (337)"
4 "Loss of Sandy Pond to Tewksbury 345 (337) with Y1 51 SPS" 5 "Loss of Woburn to Tewksbury 345 (338)"
6 "Loss of Golden Hills to Tewksbury 345 (339)"
7 "Loss of Ward Hill to Seabrook 345 (394)"
8 "Loss of Ward Hill to Seabrook 345 (394) with Y151 SPS" 9 "Loss of Ward Hill to Seabrook 345 (394) with Y151 SPS & 326 SPS (WyVman 4)"
10 "Loss of Ward Hill to Seabrook 345 (394) with YI 51 SPS & 326 SPS (Newington)"
11 "Loss of Ward Hill to Seabrook 345 (394) with YI51 SPS & 326 SPS (N & W)"
12 "Loss of (385) Buxton-Deerfield [nOl]"
13 "Loss of (391) Buxton-Scobie [n03]"
14 "Loss of (307) Deerfield-Newington" 15 "Loss of (373) Deerfield-Scobie" 16 "Loss of (363) Scobie-Seabrook" 17 "Loss of (379) Scobie-Amhrst-V.Yankee" 18 "Loss of (369) Seabrook-Timber-Newington" 19 "Loss of (343) Sandy Pd-Millbury #1" 20 "Loss of (314) Sandy Pd-Millbury #2" 21 "Loss of (381) VT Yankee-Northfield" 22 "Loss of (346X) Woburn-No.Cambridge #1" 23 "Loss of (358) No.Cambridge-Mystic" 24 "Loss of (349X+Y) Mystic-G.Hills, Golden Hills TX" New England 345kV transformers 25 "Loss of GLDN HILL TX 2" 26 "Loss of SANDY PD TX I" 27 "Loss of SANDY PD TX 2" 28 "Loss of WARDHILL TX 3" 29 "Loss of WVARDHILL TX 3 with Y151 SPS" 30 "Loss of(TB14) Deerfield 345-115 kV TX" 31 "Loss of (TB30) Scobie 345-115 kV TX" 32 "Loss of(T2) Golden Hills 345-1l SkV TX" 345KV Stuck Breaker Contingencies 33 "Sandy Pond Stuck Breaker 314" 34 "Sandy Pond Stuck Breaker 337" 35 "Sandy Pond Stuck Breaker 337 with YI 51 SPS" 36 "Sandy Pond Stuck Breaker 343" 37 "Sandy Pond Stuck Breaker 326" 38 "Sandy Pond Stuck Breaker 326 with Y151 SPS" 39 "Sandy Pond Stuck Breaker 2643" 40 "Sandy Pond Stuck Breaker 2643 with Y151 SPS" 41 "Tewksbury Stuck Breaker 3739" 42 "Tewksbury Stuck Breaker 3739 with Y151 SPS" 43 "Tewksbury Stuck Breaker 3894" 44 "Tewksbury Stuck Breaker 3894 with Y151 SPS" GEII-PSEC 38
45 "Tewksbury Stuck Breaker 3894 with Y151 SPS & 326 SPS (Wyman 4)"
46 "Tewksbury Stuck Breaker 3894 with Y 151 SPS & 326 SPS (Newington)"
47 "Tewksbury Stuck Breaker 3894 (394) with Y151 SPS & 326 SPS (N & W)"
48 "Tewksbury Stuck Breaker 3894-2" 49 "Tewksbury Stuck Breaker 37-39" 50 "Deerfield Stuck Breaker 851 51 "Deerfield Stuck Breaker 785" 52 "Deerfield Stuck Breaker 72" 53 "Deerfield Stuck Breaker 731 o" 54 "Newington Stuck Breaker 0372" 55 "Newington Stuck Breaker 0163" 56 "Newington Stuck Breaker 0451" 57 "Newington Stuck Breaker SEI-New v" 58 "Scobie Stuck Breaker 731" 59 "Scobie Stuck Breaker 631 "
60 "Scobie Stuck Breaker 911 61 "Scobie Stuck Breaker 7973" 62 "Scobie Stuck Breaker 6366" 63 "Scobie Stuck Breaker 9126" 64 "Scobie Stuck Breaker 262" 65 "Scobie Stuck Breaker 792" 66 "Buxton stuck breaker (K386-4)"
New England 230kV lines 67 "A-201Nn 68 "A-201 S 69 "B-202Nn 70 "B-202Sn 71 "Loss of GRAN to COMERFRD (F-206)n New England 230kV transformers 72 "Loss of TEWKSBRY TX 2" 73 "Loss of TEWKSBRY TX 3" 74 "Loss of TEWKSBRY TX 4" 75 "Loss of TEWKSBRY TX 3 and 4" 76 "Loss of TEWKSBRY TX 3 and 4 vith Y151 SPS" NGRID 115kV lines 77 "B-154N" 78 "C-155Sn 79 "1-161 W 80 "J-162" 81 "K137E "
82 "M-139 "
83 "0-167 "
84 "Q-169" 85 "S-145" 86 T-146 "
87 "G-133E" 88 "G-133E+ Y151" 89 "G-133W" 90 "K-137+T4" 91 "K-137W+T6" 92 "L138E" 93 "N-140" GEII-PSEC 39 GEII-PSEC 39
94 "Yj151 95 "B-154S" 96 "C-155N" 97 "F-158N&S" 98 "F-158N" 99 "F-158S" 100 "A-153" 101 "1-161W" 102 "J-162" 103 "L-164" 104 "N-166" 105 "P-168 128518K 106 "Q-169" 107 "A-179" 108 "517-532N&S" 109 "517-533N&S" NGRID double-circuit towers (DCT) 115 & 69kV - partial 110 "337+161wDCT" 111 "337+161w+151" NGRID 115 kV STUCK BREAKERS 112 "GLDN H 45-58" 113 "GLDN H 46-69" 114 "GLDN H T-146" 115 "S.HBR 11-45" 116 "S.HBR 44-55" 117 "S.HBR 33-54" 118 "SDNVRS C-155" 119 "SNDYPD K137E" 120 "TEWKS 37-2 "
121 'TEWKSK137" 122 "TWKSK137+151"_
123 "WRD_HL_33-54" 124 "WH_33-54+151 "
125 "SNDYPD L138E" 126 "SPD L138E151" 127 "TEWKS 4T" 128 "TEWKS 4T+151" 129 "TEWKS 2T" 130 "TEWKS 2T+151 n 131 "TEWKS 39-46" 132 "TEWKS 40-45" 133 "SDNVRS B-154" 134 "WRD HL G-133" 135 "WH G-133+151" 136 "GLDN H F-158" 137 "GHF-158+Yl51" 138 "GLDN H 46-69" LOSS OF GENERATION 139 "LOSS OF MYSIC 8" 140 "LOSS OF CON ED NEWINGTON GI, G2 AND G3" 141 "Loss of Seabrook Gl" 142 "Loss of Merrimack G2" GEII-PSEC 4U GEII-PSEC 4()
Additional Contingencies 143 "LOSS OF 340" 144 "LOSS OF 340 AND 379" 145 "LOSS VY AUTO" Light Load Contingencies ILT Loss of Chester SVC 2LT Loss of Mystic 7 3LT Loss of AES Londonderry 4LT Loss of Vermont Yankee 5LT Loss of one Scobie 345-115 TX plus one shunt reactor 6LT Loss of one Surowiec 345-115 TX plus one shunt reactor 7LT Loss of one Orrington 345/115 TX plus one shunt reactor GEII-PSEC 41 GEII-PSEC 41
Appendix B Seabrook Auxiliary System Model The Seabrook auxiliary system is normally supplied by two 3-winding transformers from the generator terminals. The following data was supplied by the Seabrook plant staff.
Unit Auxiliary Transformers Voltage (H-X-Y): 24.5 kV - 13.8 kV - 4.3 kV H - WDG. MVA:
27 1 361 (45) OANFAN(FOA)
X - WDG. MVA:
18 / 24 / (30)
Y-WDG.MVA:
12/16/(20)
ZH-x=
ZH-Y =
ZX.Y=
Load Loss H-X =
H-Y =
X-Y =
X2A 4.99%
5.47%
9.78%
41358 41120 46600 X2B 5.05%
5.48%
9.80%
40842 41268 46285
[taps set at nominal]
@ 18 MVA
@ 12 MVA
@ 12 MVA W@18MVA W @ 12 MVA W @ 12 MVA Recorded Currents and Voltages - Dec. 15, 2003 VTERM = 24.6 kV (0.984 pu)
ITERM = 27.8, 28.6,28.5 kA (phase A,B,C)
VBAsE = 25 kV MVA = 1206 Aux. Bus I
2 3
4 5
6 VAUX (kV) 13.36 13.51 4.227 4.221 4.225 881 0.968 20.4 721 0.979 16.87 496 1.016 3.63 531 1.015 3.88 397 1.016 2.91 303 1.015 2.22 Total MVA 49.91 Large nASEL(kV) Motors (HP)*
13.8 20,800 13.8 17,400 4.16 8,250 4.16 6,600 4.16 5,850 4.16 5,650 X2A supplies aux. buses I and 3 X2B supplies aux. buses 2,4, 5, and 6
- Total of motor HP on each bus from station one-line diagram Based on this information, the auxiliary system was modeled as follows:
One equivalent 3-winding tranformer with the following winding voltages and impedances:
VI, = 24.5kV
-x = 13.8kV Vy= 4.3kV XI.X = 0.05 Xi-Y = 0.082 Xx.y =0.147 on 36 MVA base all R's = 0.
on 36 MVA base on 36 MVA base GEII-PSEC 42 GEII-PSEC 42
The load on the 13.8kV bus was modeled by a single equivalent motor consuming 32 MW and 16 MVAr.
The load on the 4.16kV bus was modeled by one equivalent motor consuming 10 MW and 5 MVAr (9 MW and 4.5 MVAr pre-uprate) and a static (constant impedance) load consuming 7 MW and 2 MVAr.
The MVA bases for the dynamic motor models for the 13.8kV and 4.16kV motors were set at 50 MVA and 15 MVA, respectively. The dynamic model parameters used for both motors were:
Is
'p Ipp 11 ra tpo tppo h
d sel se2 Wt tv 2.5000 0.200000 0.200000 0.120000 0.005000 0.500000 0.0 1.000000 2.0000 0.050000 0.300000 0.652000 10.0000 voltage trip setting voltage trip time (set high so tripping would not occur)
GEII-PSEC 43 to NYN-04032
Stephen G. Whitley Senior Vice President & Chief Operating Officer February 11, 2004 Mr. Mark R. Sorensen FPL Energy P.O. Box 14000 Juno Beach, FL 33408 Mr. Fernando DaSilva FPL Energy, LLC.
8 Woodland Road Assonet, MA 02702
Subject:
FPLE-04-GO1 Gentlemen:
ISO New England has determined pursuant to Section 18.4 that implementation of the Participant plan identified in the following application will not have a significant adverse effect on the reliability or operating characteristics of the Participant that submitted the application or upon the system of any other Participant, subject to satisfaction of any conditions identified below with respect thereto:
FPL Energy Seabrook LLC (FPLE) Subordinate Generation 18.4 Application FPLE-04-GO1 for increasing the gross electrical megawatt output of Seabrook Station Unit 1, located in Seabrook, New Hampshire (the "Project"), by 86 MW (1209 MW to 1295 MW), as the first phase of two phases that will commence on April 1, 2005, as detailed in Mr. Mark Sorensen's January 23, 2004 transmittal to Mr. Stephen Rourke, Chairman - NEPOOL Reliability Committee, subject to the following conditions:
- 1. The Project having the net ratings of 1246 MW at 20 OF, 50 OF and 90 OF; a gross maximum plant rating of 1295 MW; and a gross reactive capability, under full output conditions, of 0 MVAr leading and 367 MVAr lagging.
- 2. Seabrook Station Unit 1, with implementation of its proposed 1295 gross MW uprate or any lesser uprate, will be required to limit Its gross output level in real-time operation such that the net loss of source that results from a contingent Seabrook generator trip is at or below the real-time-based maximum allowable net source loss for the NEPOOL Control Area. Any reductions to the gross output of Seabrook Station Unit 1 to meet this requirement will be required within 30 minutes of being directed to do so by ISO New England.
2
- 3. The NEPOOL Reliability Committee reviewing the findings of an assessment of the impacts of the Project on the appropriate Underexcited Reactive Ampere Umit setting on the excitation system of Seabrook Station Unit 1 and making a recommendation to the ISO regarding those findings, which may include the implementation of changes to the setting.
- 4.
Completion of any additional transmission modifications required for the Project that may result from the development of any or all of the Relevant Queued Resources to the extent required under the Subordinate 18.4 Application Policy. These relevant Queued Resources include:
Berwick Energy Center Vermont Yankee Power Uprate, Steps 1 & 2 UAE Tewksbury UAE Lowell Neptune Phase 5 Maine Yankee Export Neptune Phase 7 Wyman Export Second New Brunswick Tie Project Orrington South Expansion The above plan is hereby approved for implementation.
Sincerely, Stephen G. Whitley Senior Vice President and Chief Operating Officer cc: 18.4 Application 3SO New England Inc.- One Sullivan Rd., Holyoke, MA 01040 - Tel: 413/535-4361 / Fax: 413/535-4150 to NYN-04032
The State of New Hampshire D
Department of Environmental Services Michael P. Nolin Comnuissioner January 26, 2004 Mitchell S. Ross Senior Attorney FPL Energy, LLC PO Box 14000 Juno Beach, Florida 33408-0420
Dear Mr. Ross:
On December 1, 2003, the New Hampshire Site Evaluation Committee (Committee), in public session, considered the jurisdictional inquiry contained in your letter of June 25, 2003. As you know FPL Energy, LLC (FPL) was permitted to make a presentation to the Committee at that meeting. The Committee also considered questions raised by various agencies and the public regarding the inquiry.
After careful consideration the Committee voted to allow me to respond to your request in the following fashion.
Based upon the representations contained in your letter of June 25, 2003; the information contained in your supplemental filings of September 19, 2003 and December 11,2003; and the information provided at the public meeting on December 1, 2003; it appears that the proposed upgrade of the Seabrook Station nuclear power facility does not trigger the jurisdiction of the Committee under RSA 162-H. The Committee understands that FPL intends to replace and/or upgrade certain equipment throughout Seabrook Station, which will increase the overall production capacity of the facility by approximately six percent (6%). Seabrook Station has a present generating capacity of 1206 MWe. The proposed uprate will increase that generating capacity to 1308 MWe.
The Committee further understands that any and all construction necessary to the proposed upgrade will occur within the footprint of the presently existing facility. Thus, there will be no impact on the orderly development of the region, and there will be no unreasonable adverse impacts on aesthetics, historic sites, air and water quality, the natural environment or public health and safety. More specifically you have represented that the plant will continue to operate within the terms and conditions of its National Pollutant Discharge Elimination System (NPDES) permit and that no amendment of that permit will be necessary.
Given the overall existing capacity of the facility, the Committee does not find that the upgrade detailed in your request is a sizeable change or addition to the facility requiring the filing of a formal application and compliance with the statutory I 4}'VtD B Y FE
{ 2, P.O. Box 95, 29 Hazen Drive, Concord, New Hampshire 03302-0095 N S Telephone: (603) 271-3503
- Fax: (603) 271-2867
- TDD Access: Relay NH 1-800-71a.
DES Web site: www.des.nh.gov
Mitchell S. Ross January 26, 2004 Page 2 RSA 162-H. The Committee recognizes that the existing unit was only certificated for a generating capacity of 1100 MWe. To the extent necessary, the Committee authorizes the increase in generating capacity.
You should be advised that the Committee's action in this regard is based upon the representations made by FPL. Should a change of circumstances occur the Committee might, indeed, advise FPL that a formal application and compliance with the requirements of RSA 162-H is required. Please note that the decision contained in this letter should not be considered as precedent and may not be relied upon by FPL with regard to future upgrades or construction at Seabrook Station or any other facility.
Please note that nothing contained in this letter should be construed to relieve FPL from the applicable requirements of other existing state, federal and local regulatory agencies, including but not limited to the United States Nuclear Regulatory Commission, the United States Environmental Protection Agency, the State of New Hampshire Department of Environmental Services, and the Town of Seabrook.
Sincerely, MichaelP. NP n, Chairman New Hampshire Site Evaluation Committee MPN/hyv cc:
Site Evaluation Committee Members G. Dana Bisbee, Pierce Atwood Jennifer Patterson, Attorney General's Office