MOSES SOUTH STABILITY LIMIT FOR THE PROPOSED T 12 CHATEAUGUAY TRANSFORMER OPERATING CONFIGURATION WITH BOTH HVDC POLES O/S

Transcription

1 Approved by OC on 10/15/09 MOSES SOUTH STABILITY LIMIT FOR THE PROPOSED T 12 CHATEAUGUAY TRANSFORMER OPERATING CONFIGURATION WITH BOTH HVDC POLES O/S Report #: Chat 09 Prepared by Operations Engineering Staff New York Independent System Operator, Inc. September 24, 2009

2 TABLE OF CONTENTS I. INTRODUCTION... 3 II. RECOMMENDATION... 3 III. DISCUSSION Projects Description 3.2 Study Methodology 3.3 Interface Definition 3.4 Base Case Development 3.5 Transfer Case Development 3.6 SVC's/STATCOM NormalOperating Mode IV. RESULTS Stability Limit Analysis 4.2 Stability Limit Analysis Results 4.3 Conclusions TABLES: Table 1: Moses South Stability Analysis Resul Table 2: Moses South Interface Definition Table 3: Description of Simulated faults for this Analysis FIGURES: Figure 1: One Line/Breaker Diagram Existing Chateauguay Bus Arrangement Figure 2: One Line/Breaker Diagram Proposed New Chateauguay Bus Arrangement APPENDICES: APPENDICES A1. Power / Load flow Summary Base Case with transfers stressed with L33/L34 B1. Power Flow Transcription Diagram Base Case with transfers stressed with L33/L34 C1. Dynamics Simulation Plots Base Case with transfers stressed with L33/L34 A2. Power / Load flow Summary Alternate Case w/ transfers stressed with wind B2. Power Flow Transcription Diagram Alternate w/ transfers stressed with wind B2. / Dynamics Simulation Plots Alternate Case w/ transfers stressed with wind - 2 -

3 I. Introduction The current Moses-South stability limit for both HVDC poles out of service, (2000 MW), was developed with the existing Chateauguay configuration, which permitted a maximum potential Chateauguay-Massena transfer of 1170 MW. Hydro Quebec (HQ) has proposed a new Chateauguay configuration that would reconnect the T12 transformer to the New York system for the system condition where both HVDC poles are out of service. Figures 1 & 2 below show the current and the proposed configurations. The new configuration, with the T-12 transformer reconnected to the New York system will permit additional generation from Beauharnois West to be synchronously connected to New York system. The potential maximum Chateauguay-Massena transfer under the new configuration will increase from 1170 MW to 1370 MW. With this new configuration at Chateauguay, it is necessary to re-evaluate and confirm the existing Moses South stability limit for the proposed system configuration, with both HVDC poles (GC1 & GC2) out of service. This report documents the Moses-South stability limit under the new configuration and transfer conditions. The summary of the analysis can be found in Table 1. The Moses South Interface is defined in Table 2. All assumptions are documented in the base case development section of the report. This report includes the results of the stability analysis, copies of stability plots, and base case assumptions made in developing the transfer cases. II. Recommendation: For the condition where both Chateauguay HVDC poles are unavailable, the existing Moses South stability limit of 2000 MW continues to be valid for the proposed configuration with the Chateauguay T-12 transformer synchronously connected to New York, and 1370 MW being transferred from Chateauguay to Massena. On the Summary of NYISO Interface Limits and Operating Studies the definition of the relevant Moses-South limit should be revised from 2 HVDC Poles O/S (MAX CHAT -MASSENA = 1170 MW) to 2 HVDC Poles O/S (MAX CHAT -MASSENA = 1370 MW) The limit itself will remain at 2000 MW. The limit stated above is a confirmation of the existing limits. This analysis did not intended to propose an increase in the Moses South limits, but to confirm the existing limits. Table 1, shows the actual test level and the operating margin limit for the configuration under study

4 Table 1 RECONFIGURATION OF CHATEAUGUAY TRANSFOMERS Summary Of Stability Limit Analysis for Moses South Interface (2 HVDC Poles O/S, 1200 MW A/C) Case No/Name Base Case Description Moses South BaseCase Moses South Stability Transfer Level Limit with 10% Margin Case7A 2 HVDC Poles (GC1 & GC2) O/S 2390 MW 2150 MW MS-2230_2#HVDC-OS_t4.sav (MSC-7040 = 1370 MW A/C) 120 kv Split Bus Configuration L33 & 238 MW Each Existing Limit = 2000 MW 3 Oswego & 6 Sithes Units I/S Chat SVCs both I/S Chat Harmonic Filters O/S Marcy FACTS, Leeds/Fraser SVCs IS Moses South Transfer = 2390 MW Central East Transfer = 3060 MW III DISCUSSION: 3.1 Project Description Figure 1 & 2 below shows the existing Chateauguay bus arrangement and the proposed new transformer configuration. With the new configuration, there are; 22 generators connected on transformer T11 and T13 with lines 1362 & generators connected on transformer T12 with lines 1291 & 1292; The T12 is separate from the other transformers on the 120 kv bus; With the new configuration, Transformer T12 was placed back onto the New York system to allow more generation from Beauharnois West to be synchronously connected to New York system. Available generation from Beauharnois during outage of both HVDC poles would be increased from 1170 MW to 1370 MW. The Chateauguay 765/120 transformers would be split on the 120 kv side due to unit stability limitations

5 Figure 1: Existing Chateauguay Bus Arrangement - 5 -

6 Figure 2: Proposed New Chateauguay Bus Arrangement Note 1: Transformer T12 is connected directly to the Chateauguay 765 kv (NY) bus by Closing existing (2) disconnects and opening other (3) disconnects to the HQ system. The 120 kv lines between Chateauguay and Beauharnois kv Substations are not connected to the Chateauguay 120 kv bus. This configuration will be implemented if the GC1 and GC2 are assumed out of service due to outages on both converters

7 3.2 STUDY METHODOLOGY The analysis for this evaluation was done in accordance with the NYSRC Reliability Rules, Standards for Planning and Operation the New York ISO Bulk Power System and the NYISO Transmission Planning Guideline #2.0. These Guidelines conform to NPCC A-2 Basic Criteria for the Design and Operation of Interconnected Power Systems. 3.3 INTERFACE DEFINITION The elements listed in Table 2 constitute Moses South Interface Definition. TABLE 2 Moses South Interface Definition Name Line ID Voltage (kv) *Massena-Marcy MSU1 765 *Moses-Adirondack MA *Moses-Adirondack MA *Dennison-Colton *Dennison-Colton *Alcoa-N. Ogdensburg Malone-Colton* BASE CASE DEVELOPMENT The study used the 2007 series, NERC/MMWG with a detailed summer 2008 NYISO Load flow/dynamics representation. Study cases were setup as described in table 1. The table describes the status of the Chateauguay HVDC, the maximum Chateauguay Massena (MSC-7040) transfer and the status of the 3 transformer banks (760/120 kv). The Chateauguay 765/120 transformers would be split on the 120 kv side due to shortcircuit limitations. The new transformer configuration was connected as described in Figure 2 above. The load flow and dynamic data file for the Beauharnois units used for the original Moses-South stability limit study was updated by Hydro Quebec. Fourteen of the thirty five Beauharnois machines have been equipped with Power System Stabilizes (PSS). The North Country wind projects with name plate capacity of about 400 MW were modeled in the case dispatched to 160 MW, which represents about 40 percent of the name plate value

8 The Aluminum and GM plant load of about 260 MW and 14.6 MW respectively, located North of Moses South interface, were modeled out of service in the base case to reflect changes in system conditions that have occurred since the NERC/MMWG reference case was developed. The 1250 MW HVDC connection from Hydro Quebec to Hawthorne, Ontario, presently entering service was not modeled in the summer 2008 peak load base case used for this analysis. For details on the base case configuration for each scenario, refer to the transcription diagram and summary of the load flow base case in the appendixes. 3.5 Transfer Case Development The transfer case employed generation shifts between Hydro Quebec (Beauharnois machines), and New York systems to adjust/increase transfers across Moses South and Central East interface. Historically, it has been necessary to employ the phase shifter controlled L33/L34 ties to stress the flows across Moses South at the appropriate test levels. The base transfer case for this analysis continued to schedule energy transfers from Ontario into New York by scheduling 238 MW across L33 and L34. Base case load flow summaries and a transcription of the Chateauguay station can be found in Appendices A-1 and B-1. With the installation of significant wind resources north of Moses South there is the capability to stress the interface for a variety of resources. An alternate transfer case was developed with L33 and L34 scheduled at zero flow, and the Moses South interface stressed with the full output of the available wind generation. Alternate transfer load flow summaries and a transcription of the Chateauguay station can be found in Appendices A-2 and B SVC/STATCOM Normal Operating Mode The Leeds/Fraser SVC and Marcy STATCOM are modeled in service, the base case load flow were solved with the SVCs/STATCOM set to minimum (0Mvar) output by adjusting their respective voltage schedules in the pre-contingency case

9 IV RESULTS 4.1 Stability Limit Evaluation Table 3 below outlines the identifiers and description of the contingencies tested for this analysis. In both the base and alternate transfer scenarios the tested Moses South contingencies were all stable. There were no significant differences in system performance between the transfer case where L33 and L34 were each scheduled at 238 MW, and the transfer case where L33 and L34 were each scheduled at zero. Power/Load flow summaries and selected resulting simulation plots are attached in the Appendicies. The contingencies performed for this analysis, were tested and evaluated in accordance with the NYISO Transmission Planning Guideline #3 Guideline for Stability Analysis and Determination of Stability-Based Transfer Limits. The NYISO stability transfer limit, obtained from a stable simulation of the most severe contingencies, is obtained by reducing the test transfer level of the interface in question by the larger of: - 10% of the pre-contingency transfer on the interface, or MW - 9 -

10 Table 3 Simulated Faults For Moses South Stability Limit Study Fault No. Fault Description MS01 3PH-NC@MARCY 765/MASSENA-MARCY MSU-1 W/REJ. RADIAL QUEBEC GEN. MS02 3PH-NC@MOSES 230KV/MOSES-ADIR-PORTER W/NO REJ. MS03-rej4 LLG@MOSES 230/MOSES-ADIR-PORTER W/4-UNIT REJ MS03 LLG@MOSES 230/MOSES-ADIR-PORTER W/no UNIT REJ MS04 3PH-NC@MOSES 230/MASSENA-MOSES 765/230 MMS-1 MS05 3PH-NC@MASSENA 765/MASSENA-MOSES 765/230 MMS-1 MS06 SLG-STK@MOSES/MASSENA-MOSES MMS-1 W/NO REJ MS07 SLG-STK@MASSENA765/MASSENA-MOSES 765/230 MMS-1 MS08-rej4 SLG-STK@MOSES /MOSES-ADIR.-PORTER 230 W4-UNIT REJ MS08-rej8 MS08-8 SLG-STK@MOSES /MOSES-ADIR.-PORTER 230 W/8-UNIT REJ MS08 SLG-STK@MOSES /MOSES-ADIR.-PORTER 230 W/NO REJ MS09 3PH-NC@MASSENA 765/MASSENA-MARCY MSU-1 W/REJ MS10 SLG-STK@MOSES /MOSES-WILLIS-PLATT 230 MS11-rej8 SLG-STK@MOSES 230/MASSENA-MOSES 230#MMS-2 W/8REJ (MS06 with Rej.) MS12 3PH-NC@CHATEAUGUAY 765KV/CHATEAUGUAY-MASSENA MSC-7040 MS13 LLG@MOSES /MOSES-MASSENA 230 MS15-rej4 LLG@MOSES 230/MOSES-ST.LAWRENCE L33/34P R0 MS15-rej8 LLG@MOSES 230/MOSES-ST.LAWRENCE L33/34P R0 MS15 LLG@MOSES 230/MOSES-ST.LAWRENCE L33/34P R0 CE03 SLG/STK@EDIC345/EDIC-N.SCOT#14;BKUP CLR@FITZ345 CE07AR ON MARCY-COOPER & EDIC-FRASER DBL CKT CE15 SLG/STK@MARCY345/VOLNEY-MARCY VU-19/STK@MARCY 345 NYISO-2 3PH@ADIRONDACK- PORTER 230 NYISO-3 No fault Loss of ADIRONDACK- PORTER STABILITY LIMIT ANALYSIS RESULTS: Moses South design criteria contingencies and select limiting Central East contingencies were simulated. The results can be found in Appendix C and support the limits presented in Table 1.. With Moses South at its margined limit of 2390 MW, Central East at its stability limit of 3050 MW (3 Oswego, 5/6 Sithe) and MSC-7040 flow of 1370 MW, the system response/oscillations was well damped and stable

11 4.3 CONCLUSIONS: For the condition where both HVDC poles are unavailable, the existing Moses South stability limit of 2000 MW continues to be valid for the Chateauguay configuration with the T-12 transformer synchronously connected to New York. The new configuration, with the T-12 transformer reconnected to the New York system will permit additional generation from Beauharnois West to be synchronously connected to New York system. The capability to transfer energy from Beauharnois to New York may be increased from 1170 MW to 1370 MW