ABB Inc. Public Service Company of New Mexico Broadview Full Buildout Affected PSLF Study

Transcription

1 ABB Inc. Public Service Company of New Mexico Broadview Full Buildout Affected PSLF Study Final Report ABB Power Systems Consulting June 27, 2016

2 LEGAL NOTICE This document, prepared by ABB Inc, is an account of work sponsored by Public Service Company of New Mexico (PNM). Neither PNM nor ABB Inc. nor any person or persons acting on behalf of either party: (i) 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 this report may not infringe privately owned rights, or (ii) assumes any liabilities with respect to the use of or for damages resulting from the use of any information, apparatus, method, or process disclosed in this document. Prepared for: Public Service of New Mexico (PNM) Report No.: E A-R01 Date: June 27, 2016

3 Power Systems Consulting Technical Report ABB Inc. Public Service Company of New Mexico Broadview Full Buildout Affected PSLF Study Executive Summary: E A-R01 Dept. Date Consulting June 27, 2016 Pages 714 PNM has requested that ABB perform power flow and stability technical studies to increase the power injections on the BA-Blackwater 345 kv line (BB line) to the maximum level of 1000 MW. Previous technical studies of 832 MW power injection on the BB line have shown that a Static VAR Compensator (SVC) at the Guadalupe 345 kv station is necessary to provide the required voltage support to accommodate these power transfers. The 1000 MW BB line power injections requested by PNM for this study are: El Cabo wind farm at Clines Corner: 213 MW Broadview wind farm: 497 MW Taiban Mesa: 200 MW Aragonne Mesa: 90 MW This study includes the Guadalupe SVC rated 250 MVAr capacitive to 100 MVAr inductive. The goal of this study is to determine if additional voltage support is required beyond the planned Guadalupe SVC for the 1000 MW full buildout power injection. Several study tasks were performed to assess the system impact of the extra power injections on the BB line. The conclusions from the study tasks were as follows: Powerflow contingency analysis on the study base case shows that, for the analyzed contingencies, no substantial voltage/thermal violations occurred on the BB line. Acceptable North American Electric Reliability Corporation (NERC) Transmission Planning (TPL) performance is achieved without additional reactive power support. Voltage stability margin analysis (QV analysis) on the study base case and two stress cases demonstrated that, for the analyzed contingencies, positive reactive margin is maintained at Guadalupe. As such, the BB line transfers meet the WECC voltage stability margin criteria. Dynamic simulation on the study base case with selected N-1 and N-2 contingencies shows that, for all studied disturbances, adequate system dynamic performance and adequate post-fault voltage recoveries are achieved. All wind power plants on the BB line are able to ride-through the studied faults. Dynamic simulation of selected N-1 contingencies on a sensitivity case with Blackwater HVDC in service at 15 MW East-to-West showed stable performance. The BB line wind power plants and the Blackwater HVDC are able to ride-through the studied faults The technical studies thus did not identify a need for additional voltage support beyond the Guadalupe SVC for the 1000 MW full buildout scenario. The system was found to meet the NERC TPL criteria and the WECC voltage stability margin criteria. All the wind farms on the ii

4 BB line were found able to ride through the studied faults with adequate post-fault voltage recoveries. However, the limitations of the positive sequence models used in this study cannot guarantee that a synchronous condenser at Blackwater station is not required to insure sufficient short circuit capacity in the full buildout scenario for inverter based generation 1. PSCAD studies (3-phase model) are being performed in a separate study to evaluate whether a synchronous condenser at Blackwater station will be required to support the power injection conditions as stated above. Rev # Revision Date Author Reviewed 1 PNM Comments June 27, 2016 Huimin Li D Dickmander DISTRIBUTION Public Service New Mexico 1 WECC White Paper: Value and Limitations of the Positive Sequence Generic Models of Renewable Energy Systems neric%20model%20limitations%20december% docx&action=default&defaultitemopen=1 iii

5 TABLE OF CONTENTS 1 Introduction PSLF Model Setup STARTING CASE CONDITIONS STUDY CASE SETUP (TASK1A) Broadview Wind Farm Setup El Cabo Wind Farm Setup Guadalupe SVC Setup Blackwater HVDC Setup Power Flow Analysis CONTINGENCY ANALYSIS (TASK 1B) QV ANALYSIS (TASK 1C) QV Analysis Assumptions QV Analysis Results Guadalupe SVC Headroom QV Analysis Conclusions Dynamic Simulations DYNAMIC SIMULATION CONFIGURATIONS AND CASE LIST DYNAMIC SIMULATIONS WITH NOMINAL BB LINE LOAD ANALYSIS (TASK 1D) SENSITIVITY CASE DYNAMIC ANALYSIS (TASK 1E) Conclusions and Recommendations References Appendices...34 APPENDIX A. CONTINGENCY ANALYSIS RESULTS, NOMINAL LOAD ON BB LINE APPENDIX B. DYNAMIC SIMULATION PLOTS APPENDIX C. SENSITIVITY DYNAMIC SIMULATION RESULTS

6 1 Introduction PNM has requested that ABB perform power flow and stability technical studies to increase the power injections on the BA-Blackwater 345 kv line (BB line) to the maximum level of 1000 MW. Previous technical studies of 832 MW power injection on the BB line have shown that a Static VAR Compensator (SVC) at the Guadalupe 345 kv station is necessary to provide the required voltage support to accommodate these power transfers. The models and databases for the recently completed studies serve as the starting point for adding the additional wind resources included in the full buildout scenario. The goal of this study is to determine if additional voltage support is required beyond the planned Guadalupe SVC for the power injection assumptions in Figure 1-1 on PNM s 216-mile, 345 kv transmission path between Blackwater station and the BA station north of Bernalillo, New Mexico. To Four Corners Rio Puerco 345 kv To San Juan Norton 345 kv bus El Cabo 345 kv Iberdrola El Cabo 213 MW Wind Type 3 Gamesha Wind Turbines 34 miles El Cabo 34.5 kv Bus 34.5kV/345 kv transformer El Cabo 345 kv Bus /-100 MVAR svc Tiaban Mesa 200 MW Type 3 GE Wind Turbines Black Water 345 kv Broadview 497 MW Wind Type 4 Siemens Wind Turbines 44 miles Broadview 34.5 kv Bus 34.5 kv/345 kv transformer Broadview 345 kv Bus 6 Miles 54 Miles 31 Miles To West Mesa BA 345 kv To 115 kv System Guadalupe 345 Aragonne 138/345 kv transformer miles 70 Miles Taiban Mesa 345 kv Aragonne 138 kv Bus 4 62 Miles Blackwater Converter Aragonne 138 kv Bus 3 Aragonne 34.5kV/138 kv transformer Aragonne 34.5 kv Bus 2 DSTATCOM Aragonne Mesa 90 MW Type 1 Mitshubishi Wind Turbines Figure 1-1: Study Configuration on the Blackwater-BA 345kV Line Existing Transmission System Interconnection Customer Faclities 5

7 The study steps requested by PNM are outlined below in Table 1-1. Table 1-1: Study Task Outline Task # Study case set up 1a Configure base cases Task description Powerflow study 1b Contingency analysis on the base case without stress conditions 1c QV analysis on the base case without and with stress conditions Dynamic study 1d Dynamic simulation on the base case 1e Sensitivity case with Blackwater at 15 MW E-W This report is arranged as follows to address each of the above tasks: 1. All cases including the starting case, the study base case without/with stress conditions and the sensitivity case are defined in Section Powerflow studies are described in Section 3 as follows: a. In Section 3.1, powerflow contingency studies of the base case, without stress conditions, are performed to determine if contingency performance meets steady state North American Electric Reliability Corporation (NERC) Transmission Planning (TPL) criteria. The focus of the analysis is limited to defining adequate voltage support between BA and Blackwater for the full buildout conditions, and identify overloads or voltage violations. Addressing overloads or voltage violations west of BA is outside the scope of this analysis. b. In Section 3.2, QV analysis is performed on the base case with and without stress conditions to confirm that transfers meet WECC voltage stability margin criteria. 3. Dynamic studies are described in Section 4 as follows: a. In Section 4.1, system configurations and case lists are described. b. In Section 4.2, dynamic simulations are performed on the base case without stress conditions. c. In Section 4.3, dynamic simulations are performed on the sensitivity case with Blackwater in service at 15 MW E-W. 4. Conclusions and recommendations of this study are presented in Section Section 6 and Section 7 list the references and the appendices of the study. 6

8 2 PSLF Model Setup 2.1 Starting Case Conditions This section describes development of based cases from the starting PSLF model from the Broadview study. The starting PSLF model that formed the basis for the studies was the base case developed for prior studies. The system data from PNM were provided in PSLF version 18 format. The following PNM equipment is included in the starting case: Broadview Generation Injection at Blackwater 345 kv: 297 MW Blackwater HVDC: 75 MW E-W Taiban Mesa: 200 MW Aragonne Mesa: 90 MW A total of 662 MW is injected on the BB line in the starting case as shown in Figure

9 Figure 2-1: One-Line for the 297 MW Broadview Case (Input to Present Study) 8

10 2.2 Study Case Setup (Task1a) Starting from the powerflow case presented in Section 2.1, the modifications listed below were made to develop the base case of the full buildout scenario. Add the 200 MW Grady wind farm at Broadview Add the 213 MW El Cabo wind farm at Clines Corner Add the 250/-100 MVAr SVC in service at Guadalupe. Disconnect the HVDC converter at Blackwater The resulting PSLF model developed as the base case for this study shown in Figure 2-2. The case was developed in PSLF version 18 format. In addition to the base case, two stress cases and one sensitivity case were developed, as shown in Figure 2-3 to Figure 2-5: The two stress cases are only for checking the WECC voltage stability margin criteria. The cases are setup by adding stress conditions on the base case. The defined stress conditions include: o Stress condition 1: Increasing each power injection on the BB line by 5.25% (5% stress case) o Stress condition 2: Increasing each power injection on the BB line by 2.56% (2.5% stress case). The sensitivity case is for checking the BB line fault recovery ability with Blackwater HVDC operates at its minimum power level E-W. The case is set up with Blackwater HVDC in service at 15 MW east to west, and with a reduced power level of the Broadview wind farm to keep the total BB line injections the same as the base case. A total of four cases were thus set up for this study to capture the above conditions. All case conditions are summarized in Table

11 Figure 2-2: One-Line for the Study Base Case 10

12 Figure 2-3: One-Line for the 5% Stress Case 11

13 Figure 2-4: One-Line for the 2.5% Stress Case 12

14 Figure 2-5: One-Line for the Sensitivity Case 13

15 Table 2-1: Study Case Conditions EI Cabo 5 EI Cabo 5-1 AM TM Grady, GWECMV1Grady, GWECMV2 BEJN1 BEJN2 BEKW BLW HVDC E-W Guad SVC RioP SVC Total BB Case Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status WTG [MW] Status P [MW] Status Status line MW Usage Starting Case NA 0 NA 0 IN 94 IN 206 NA 0 NA 0 IN 88 IN 89 IN 125 IN 75 OUT IN 677 Task 1a Base Case IN Task 1b, 107 IN 94 IN 206 IN 100 IN 100 IN 88 IN 89 IN 125 OUT 0 IN IN IN 1c and 1d Stress Case 1 IN IN IN IN IN IN IN IN IN OUT 0 IN IN Task 1c Stress Case 2 IN IN IN IN IN IN IN IN IN OUT 0 IN IN Task 1c Sensitivity IN Case 111 IN 107 IN 94 IN 206 IN 92.5 IN 92.5 IN 88 IN 89 IN 125 IN 15 IN IN 1020 Task 1e Notes: NA: not applicable to this case Starting case: Case from PNM Broadview PSLF study (662 MW injections on BB line). Base case: the full buildout scenario with 1000 MW injections on the BB line. Stress case 1: Base case with 5.25% increase on the total BB line MW injection. Stress case 2: Base case with 2.56% increase on the total BB line MW injection. Sensitivity case: Base case with Blackwater HVDC in service at 15 MW E-W schedule, and a 15MW power reduction at the Broadview wind farm. The total BB line injections are thus the same as the base case. Descriptions on each of the tasks are in Table

16 2.2.1 Broadview Wind Farm Setup The Broadview/Grady wind farm includes five sections: BEJN1, BEJN2, BEKW, GWECMV1 and GWECMV2. Type 4 wind turbines are assumed for all five sections. Detailed models of the Broadview wind farm were provided by PNM including: The wind farm collector system Wind turbine generator dynamic models based on the PSLF regc_a, reec_a, and wtgt_a models. The power flow model of each section of the Broadview wind farm is represented by aggregate models. The parameters used for the PSLF models are listed in Table 2-2. Table 2-2: Broadview Wind Farm PSLF Powerflow Model Parameters Parameter BEJN1 BEJN2 BEKW GWECMV1 GWECMV2 Note WTG Pgen [MW] Siemens SWT 2.3 VS Aggregate 497 MW Turbine GSU transformer Aggregate MVA Wind farm main transformer F/T winding kv Turbine GSU transformer R1 34.5/ / / / / Grady data: reference [2] & [3] Other data: Broadview [pu] PSCAD study Turbine GSU transformer X [pu] Wind farm main transformer MVA Wind farm main transformer / / / / /34.5 Grady data: reference [2] & [3] Other data: Broadview H/X winding kv PSCAD study Wind farm main transformer /345 kv R1 [pu] Wind farm main transformer 34.5/345 kv X1 [pu] Collector System Voltage Grady data: reference [kv] [2] & [3] Collector System R1 [pu] [a] Other data: Broadview Collector System X1 [pu] PSCAD study Collector System B1 [pu] kv Line to BV_POI_3-T~1 [b] R1 [pu] 345 kv Line to BV_POI_3-T~1 X1 [pu] 345 kv Line to BV_POI_3-T~1 B1 [pu] Notes: BEKW s high station is Broadview POI [a] Impedance is on the system 100 MVA base. [b] The 345 kv lines referenced above are the three transmission lines between the grouped wind farm sections and the wind farm main 345 kv collector bus (BV_POI_3-T~1). Impedance is on the system 100 MVA base. 15

17 2.2.2 El Cabo Wind Farm Setup The El Cabo wind farm includes two sections. All wind turbines are Type 3 machines. A detailed model of the El Cabo wind farm was supplied by PNM including: The wind farm collector system Wind turbine generator dynamic models based on the PSLF wt3g, wt3e, and wt3t models. The power flow model of each wind farm section is represented by aggregate models. The parameters used for the PSLF models are listed in Table 2-3. Note: Table 2-3: El Cabo Wind Farm PSLF Powerflow Model Parameters Parameter ELCABO 5 ELCABO 5_1 Note WTG Pgen [MW] Aggregate 213 MW at POI Turbine GSU transformer MVA Aggregate Wind farm main transformer F/T winding kv 34.5/ /0.69 Turbine GSU transformer R1 [pu] Turbine GSU transformer X1 [pu] Wind farm main transformer MVA Wind farm main transformer 345/ /34.5 H/X winding kv Reference [4] Wind farm main transformer 34.5/345 kv R1 [pu] Wind farm main transformer 34.5/345 kv X1 [pu] Collector System Voltage [kv] Collector System R1 [pu] [a] Collector System X1 [pu] Collector System B 1[pu] kv Line ELCABO2 ELCABO1 [a] R1 [pu] kv Line ELCABO2 ELCABO1 X1 [pu] kv Line ELCABO2 ELCABO1 B1 [pu] [a] Impedance is based on the system 100 MVA base. Reference [5] 16

18 2.2.3 Guadalupe SVC Setup The Guadalupe SVC is being designed as a duplicate of the Rio Puerco SVC except for the filter bank configuration which will include 5 th and 7 th harmonic filters as compared to the two fifth harmonic filters used at Rio Puerco. The total filter reactive capability will remain at 75 MVAr as with Rio Puerco SVC. For this analysis, the Guadalupe SVC is assumed to comprise the following components: One Thyristor Controlled Reactor (TCR) rated 175 MVAr. One Thyristor Switched Capactor (TSC) rated 175 MVAr. 5th and 7th harmonic filters, totaling 75 MVAr. The maximum capacitive output is attained with the TSCs switched on and the TCR at a zero conduction angle. This results in an admittance of 250 MVAr (including filters) at the SVC terminal bus. The rated inductive output, on the other hand, is attained with the TCR at full absorption and the TSCs switched out, and amounts to an admittance of 100 MVAr (including filters). Rio Puerco SVC controls two Mechanical Switched Capacitors (MSCs) and one Mechanical Switched Reactor (MSR). In this study, it is assumed that there is no MSR and MSC controlled by the Guadalupe SVC. In the power flow, the SVC is represented as a Type 5 Static VAr Device (SVD) with ID v1 and modeled on the high voltage side of the SVC's 345 kv terminal bus since the modeled controls are based on high voltage side measurements. See Figure 2-6 for the network adjacent to Guadalupe. The SVC is connected to the Guadalupe 345 kv station. For the dynamic simulation, the Guadalupe SVC model is converted to a generator model with ID g1 to interface to the user defined control algorithms. An epcl file PrepForDyd_Guad_SVC.p is modified from the similar Rio Puerco version to accomplish this conversion. Control strategies of the Guadalupe SVC are similar to those for Rio Puerco SVC, Reference [6], except that Guadalupe SVC does not need to control external mechanically switched banks. Step response tests for the Guadalupe SVC are presented in Section 4. As comparison step response of the Rio Puerco SVC is also presented. 17

19 Figure 2-6: Power Flow Data for Guadalupe SVC 18

20 2.2.4 Blackwater HVDC Setup This section only applies to the sensitivity case. Based on Reference [7], an epcl file previously developed by ABB was used to automatically configure the Blackwater filters and transformer taps for the scheduled HVDC power level. In the sensitivity case, the Blackwater HVDC scheduled power level is set at 15 MW E-W. As such, the PNM station is operated as an inverter. For operation at 15 MW, the Blackwater DC voltage is reduced from the nominal 57 kv to around 13 kv as shown in Table 2-4: Table 2-4: Blackwater HVDC PSLF Powerflow Model Parameters Parameters SPS Station PNM Station p_sched [MW] DC voltage [kv] DC Current [ka] AC Filters 2X 26.5 MVAr 3X 26.5 MVAr The resulting powerflow at Blackwater is shown in Figure 2-7. Figure 2-7: Power Flow Data for Blackwater HVDC in Sensitivity Study 19

21 3 Power Flow Analysis 3.1 Contingency Analysis (Task 1b) Contingency analysis was performed on the base case shown in Table 2-1 to confirm that steady state TPL performance criteria are met. The studied contingencies are in Table 3-1: Table 3-1: Contingency List Contingency Name Base N-0 System Intact BA-RP N-1 BA-Rio Puerco 345 kv BA345/115 TX N-1 BA 345/115 kv Transformer BA-NR N-1 BA to Norton 345 kv Contingency Description RP-WM N-1 Rio Puerco West Mesa 345 kv RP-SJ N-1 Rio Puerco San Juan 345 kv RP-FC N-1 Rio Puerco Four Corners 345 kv BAHBALRP N-2 BA 345/115 kv Transformer and BA Rio Puerco 345 kv Line RPWMHL2 N-2 Rio Puerco-West Mesa & West Mesa 345/115 kv Transformer BA-RP-N2 N-2 BA-Rio Puerco 345 kv Double-Circuit Outage The PNM-specific voltage and thermal criteria are listed in Table 3-2: Table 3-2: PNM Voltage and Thermal Criteria Area Conditions Loading Limits Voltage (p.u.) Voltage Drop Application kV and above Artesia 345 kv Normal < Normal Rating Arroyo 345 kv PST source side EPEC (Area 11) PNM (Area 10) Tri- State (zones ) Alamo, Sierra Blanca and Van Horn 69kV % 60 kv to 115 kv % Artesia 345kV Contingency < Emergency Rating % Arroyo 345kV PST source side Alamo, Sierra Blanca and Van Horn 69kV % Hidalgo, Luna, or other 345 kv buses Normal ALIS < Normal Rating kv and above* Contingency N-1 < Emergency Rating ** 6% 46 kv to 115 kv ** 6% 230 kv and above* Contingency N-2 < Emergency Rating ** 10% 46 kv and above* Normal ALIS < Normal Rating All buses Contingency N-1 < Emergency Rating % 69 kv and above except Northeastern NM and Southern NM % 69 kv and above in Northeastern NM and Southern NM Contingency N-2 < Emergency Rating % All buses *Taiban Mesa and Guadalupe 345 kv voltage range is 0.95 p.u. to 1.1 p.u. under normal and contingency conditions. ** Provided operator action can be utilized to adjust voltages back down to

22 The contingency analysis is performed based on the following assumptions: Powerflow contingency analysis focuses on the system condition immediately after the contingency. Fast closed loop controls (FACTS, HVDC) are allowed to regulate, but the mechanically switched devices such as switched capacitors and transformer taps are locked post-contingency. No head room of the Rio Puerco SVC was retained post-contingency. This means that post-contingency output for both the Rio Puerco and Guadalupe SVCs is allowed to move up to the maximum capability. Two 48 MVAr shunts at WESTMS_2 115 and SANDIA_2 115 are switched in precontingency to help the system condition. A total of 4X10 MVAr caps at the El Cabo wind farms are in service pre-contingency. WTGs of El Cabo wind farms are close to their maximum reactive limit in precontingency. Detailed results of the contingency analysis are presented in Appendix A. From the results, it is noticed that: Among all the contingencies, the highest post-contingency Guadalupe SVC susceptance reference is pu (1.0 pu Bref is 100 MVAr at nominal voltage), for the double contingency of both BA-Rio Puerco 345 kv lines. No low voltage violations were identified. Minor high voltage violations occur postcontingency at Broadview 345 kv buses. These high voltages are related to an initial voltage of pu at Broadview 345 kv from the Broadview PSCAD study. This was a result of steady-state voltage and tap conditions from debugging efforts on the Siemens wind turbine models during the Broadview PSCAD study. These violations can be removed by very minor modification to the voltage profile if needed. For the double contingency BA-Rio Puerco 345 kv 1 & 2 : o Overloads are identified on the BA 345/115 kv transformer and the 115 kv systems near the BA 115 kv station. For this double contingency, the RP-BA 345 circuits are both open post-contingency, resulting in increased flow into the 115 kv system at BA. o Overload is identified on the El Cabo to BA 345 KV line. This line is fully loaded pre-contingency, with sight (2%) post-contingency overload. Overall, it can be concluded from the contingency analysis that from the list of the analyzed contingencies, no substantial violations occurred in the monitored areas and zones (Table 3-2). Thus an acceptable TPL performance is achieved. 21

23 3.2 QV Analysis (Task 1c) QV Analysis Assumptions Steady-state reactive margin analysis (Q-V analysis) was performed at the Guadalupe 345 kv station using the GE-SSTOOLS scripts. For the Q-V analysis, the following assumptions are made: Reactive power injections are defined as the total Q at Guadalupe 345 kv station. This means that the Guadalupe SVC output is taken into account while generating the QV curves and the results. AC voltage at the Q-V test points are varied up to 1.05 pu, using an infinite reactive source at the test point. QV curves are developed only for the Guadalupe 345 kv bus. Rio Puerco SVC is modeled as a Type 5 SVD, and adjustable post-contingency. Base case Q-V curves were developed for all contingencies in Table 3-1 except for BA-Rio Puerco 345 kv Double-Circuit Outage. Q-V curves for single contingencies (Table 3-1) were developed for the 5% stress case (Stress case 1 in Table 2-1). Q-V curves for all double contingencies (Table 3-1) except for BA-Rio Puerco 345 kv Double-Circuit Outage were developed for the 2.5% stress case (Stress case 2 in Table 2-1). For the two stress cases, the Guadalupe SVC is connected pre-contingency and the Guadalupe SVC is modeled as a generator with fixed Q. 4 X 10MVAr El Cabo wind farm shunt caps are in service (total is 10 X 10 MVAr). All available Broadview wind farm shunt reactors (5 X 10MVAr) are in service. The El Cabo wind farm model included for QV analysis is set to 213 MW at the POI. The wind farm aggregate generator MVAr limits are set at the aggregate VAR capability at 213 MW Pgen. This means that when the injection level is below the nominal level, the effective power factor range is increased; when the injection level is above the nominal level, the effective power factor range is decreased. Similar to the El Cabo, the Broadview wind farm aggregate generator MVAr limits are set at the aggregate VAR capability at 497 MW Pgen. WTG VAR capability was provided by Siemens in the Broadview PSLF study. This means that when the injection level is below the nominal level, the effective power factor range is increased; when the injection level is above the nominal level, the effective power factor range is decreased. Table 3-3 summarizes the QV analysis setup. 22

24 3.2.2 QV Analysis Results Table 3-3: QV Analysis Setup QV Cases Contingency Number of QV Curves Base Case N-0, N-1 and N-2 9 Stress Case 1 N-0 and N-1 7 Stress Case 2 N-0 and N-2 3 Results from QV analysis are presented below in the plots of Figures 3-1 through 3-5, and summarized in Table 3-4 to Table 3-6. As illustrated in Figures 3-1 Figure 3-3, the slope of the QV curves for all studied outages on the three system conditions indicates stable system performance for Guadalupe 345 kv station voltages in the normal range of 0.95 pu to 1.05 pu. With increased power injections on BB line, there is a significant decrease in the reactive margin. With the N-0 condition of the three powerflow cases (Base, Stress 1, and Stress 2) taken as an example, and when Guadalupe 345 kv station operates at 0.95 pu voltage: The reserved reactive margin for base case without stress condition is ~92 MVAr 1 ; The reactive margin is decreased to ~67 MVAr 1 if the BB line load is increased by 2.56% of the nominal level; The reactive margin is further decreased to ~38 MVAr 1 if BB line load is increased by 5.25% of the nominal level. 1 Note that remaining headroom on Guadalupe SVC can be added to these values (Section 3.2.3) Figure 3-1: QV Curves at Nominal BB Line Load 23

25 Figure 3-2: QV Curves at % of Nominal Level Figure 3-3: QV Curves at % of Nominal Level 24

26 Table 3-4 to Table 3-6 summarize the reactive margins of studied outages at different system conditions. Table 3-4: Summary of Guadalupe 345 kv Bus QV Analysis at Nominal BB Line Load Configuration N-0, N-1 &N-2 Outages Minimum Reactive Margin Reactive Power Requirements MVAr [1] Guad Voltage [pu] RioP Bsvc[pu] = 1.00 = 1.04 [pu] Nominal Load No Outage Nominal Load BA-Rio Puerco 345 kv Nominal Load BA 345/115 kv Nominal Load BA-Norton 345 kv Nominal Load Rio Puerco-West Mesa 345 kv Nominal Load Rio Puerco-San Juan 345 kv Nominal Load Rio Puerco-Four Corners 345 kv Nominal Load Nominal Load BA-Rio Puerco 345 kv & BA 345/115 kv Rio Puerco-West Mesa 345 kv & West Mesa 345/115kV Notes: [1] A negative number indicates the presence of reactive power reserves while a positive number indicates that reactive power support is required to obtain a stable solution. [2] Q of Rio Puerco SVC at the point of Guadalupe minimum reactive margin (Guadalupe Voltage = 0.91 pu in Table 3-4). Positive number means SVC is delivering VARs to the system. [3] Above two footnotes also apply to Table 3-5 and 3-6. [4] See also Section Table 3-5: Summary of Guadalupe 345 kv Bus QV Analysis at % of Nominal BB Line Load Configuration N-0 & N-1 Outages Minimum Reactive Margin Reactive Power Requirements MVAr Guad Voltage[pu] RioP = 1.00 = 1.04 pu 5.25% Pre-Con Load Increase No Outage % Pre-Con Load Increase BA-Rio Puerco % Pre-Con Load Increase BA 345/115 kv % Pre-Con Load Increase BA-Norton 345 kv % Pre-Con Load Increase Rio Puerco-West Mesa 345 kv % Pre-Con Load Increase Rio Puerco-San Juan 345 kv % Pre-Con Load Increase Rio Puerco-Four Corners 345 kv

27 Table 3-6: Summary of Guadalupe 345 kv Bus QV Analysis at % of Nominal BB Line Load Configuration N-0 &N-2 Outages Minimum Reactive Margin Reactive Power Requirements MVAr Guad Voltage [pu] RioP = 1.00 = 1.04 pu 2.56% Pre-Con Load Increase No Outage % Pre-Con Load Increase 2.56% Pre-Con Load Increase BA-Rio Puerco 345 kv & BA 345/115 kv Rio Puerco-West Mesa 345 kv & West Mesa 345/115kV Guadalupe SVC Headroom As described earlier, the Guadalupe SVC output is taken into account while generating the QV curves. Unused Guadalupe SVC capacitive VARs can thus be considered as additional reactive reserves, adding to the reactive margin shown in the QV analysis results. The used and remaining (unused) Guadalupe SVC capacitive VARs for each of the QV cases is summarized in Table 3-7: Table 3-7: QV Analysis: Headroom Remaining of Guadalupe SVC QV Cases SVC output (MVAr) SVC Headroom Remaining (MVAr) Base Case Stress Case 1 (5.25% increase) Stress Case 2 (2.56% increase) QV Analysis Conclusions Based on the QV analysis, the following conclusions can be made: Positive reactive margin is seen at Guadalupe 345 kv for all studied contingencies. With increased power injections on BB line, there is a significant decrease in the reactive margin. Pre-contingency VAR support is needed at Guadalupe 345 kv station for stress cases to solve the power flow at high voltage such as 1.05 pu. Rio Puerco SVC shows relatively high capacitive output when Guadalupe voltage is at the low side, especially when the BB line load is at % of the nominal level. 26

28 4 Dynamic Simulations 4.1 Dynamic Simulation Configurations and Case List After the power flow study in Section 3, dynamic cases were run for selected N-1 or N-2 contingencies to help ensure: Adequate system dynamic performance and adequate post-fault voltage recovery. That all the existing wind power plants on The BB line will ride-through the fault. Dynamic simulations were performed on a list of contingencies as shown in Table 4-1: Table 4-1. Dynamics Case List Contingency Name Description 0 N-0 System intact, flat run 1 BA-RP 4-Cycle 3ph fault on BA-RP close to BA 345 kv. Clear BA at 4 Cycles. Clear RP at 6 Cycles 2 BA345/115 TX 4-Cycle 3ph fault at BA 345 kv, trip BA 345/115 kv Transformer at 4 cycles 3 BA-NR 4-Cycle 3ph fault at BA 345 kv, trip the BA- NR 345 kv line at the 4 cycles 4 RP-WM 4-Cycle 3ph fault at RP 345 kv, trip the RP-WM 345 kv line at the 4 cycles 5 RP-SJ 4-Cycle 3ph fault at RP 345 kv, trip the RP-SJ 345 kv line at the 4 cycles 6 RP-FC 4-Cycle 3ph fault at RP 345 kv, trip the RP-FC 345 kv line at the 4 cycles 7 GuadSvcTrp Trip the Guadalupe SVC after 1 second flat run 8 BAHBALRP N-2: 3-Cycle 3ph fault on BA-RP close to BA 345 kv. Clear BA and RP at 4 Cycles. Trip the BA345/115 kv Transformer at 4 cycles. 9 RPWMHL2 N-2: 3-Cycle 3ph fault on WW-RP close to West Mesa 345 kv. Clear WM and RP at 4 Cycles. Trip the WM 345/115 kv Transformer at 4 cycles. 10 BA-RP-N2 N-2: 4-Cycle 3ph fault on BA-RP close to BA 345 kv. Clear BA & RP at 4 Cycles. Trip the BA-RP double cks at 4 cycles. The following assumptions are used for the dynamic simulations: Dispatch as shown in Figure 1-1 (base case in Table 2-1). The Broadview and El Cabo wind farms are represented using collector system models and wind turbine models provided by PNM. As it was mentioned in Section 2.2.3, a duplicate of the Rio Puerco SVC for Guadalupe SVC is used for this study. Since the network strength at Guadalupe is different from Rio Puerco, sensitivity testing on voltage regulator gains for Guadalupe was performed. Three gain settings as listed in Table 4-2 were tested. Table 4-2: Guadalupe SVC Gain Settings Tested Guadalupe SVC Gain setting # Kp Ki

29 The gains for Rio Puerco SVC are 6 and 2300 for the proportional and integral gain respectively. As shown in Table 4-2: For the test gain setting #1, the Guadalupe SVC uses higher Kp but lower Ki as compared to the Rio Puerco SVC. A reduced integral gain was tried in all settings (#1 #2 and #3) as compared to Rio Puerco. In this study, the dynamic simulations described in Section 4.2 and Section 4.3 were performed with three Guadalupe SVC gain settings. It should be noted that the gains set in PSLF study are preliminary, and detailed settings of the SVC gains will need to be confirmed with PSCAD studies as part of the Guadalupe SVC project. 4.2 Dynamic Simulations with Nominal BB Line Load Analysis (Task 1d) For the study base case shown in Figure 2-2, dynamic simulations were run for all contingencies listed in Table 4-1. Three sets of plots corresponding to the three tested Guadalupe SVC gains are available in Appendix B, as Appendices B-1, B-2, and B-3, corresponding to the numberings given in Table 4-2. Step responses of Rio Puerco and Guadalupe SVC are also included in the three parts of Appendix B. The results show that for the base case of the full buildout scenario: With nominal BB line dispatch plus a 250/-100 MVAr SVC at the Guadalupe 345 kv station, system stability is maintained for all studied N-1 and all N-2 contingencies. All the wind power plants on the BB line are able to ride-through the studied faults For certain faults such as BA-Rio Puerco, N-1 and Rio Puerco Four Corner, N-1, oscillations in the reactive power measured at the Guadalupe side of the Guadalupe 345 kv Argonne 138 kv transformer was observed. Investigation of the oscillations indicates that the oscillations originate within the Argonne Mesa wind farm and are not related to the Guadalupe SVC. Guadalupe SVC integral gain is recommended to be lowered to 10% - 20% comparing to the Rio Puerco SVC gain settings. This is due to the weaker network strength at Guadalupe 345 kv station. 4.3 Sensitivity Case Dynamic Analysis (Task 1e) As shown in Table 2-1 and Figure 2-5, the sensitivity case was setup with Blackwater HVDC in service with a 15 MW E-W schedule, which is the minimum power of the Blackwater HVDC. The Broadview wind farm power level was also reduced by 15 MW to hold the total BB line power injection the same as in the study base case. 28

30 Dynamic simulations were run on the N-0 and N-1 contingencies listed in Table 4-1. Three sets of plots corresponding to the three tested Guadalupe SVC gains are available in Appendix C, as Appendices C-1, C-2, and C-3, corresponding to the numberings given in Table 4-2. Step responses of Rio Puerco and Guadalupe SVC are also included in the three parts of Appendix C. The results show that for the sensitivity case as dispatched in Figure 2-5: System stability is maintained for all studied N-1 contingencies. All the BB line wind power plants and the Blackwater HVDC are able to ride-through the studied faults. For certain faults such as BA-Rio Puerco, N-1 and Rio Puerco Four Corner, N-1, the previously described oscillations in reactive power measured at the Guadalupe side of the Guadalupe 345 kv Argonne 138 kv transformer was observed. Again, these oscillations originate within Aragonne Mesa and are unrelated to the SVC. The sensitivity case resulted in similar conclusions regarding SVC gain: Guadalupe SVC integral gain is recommended to be lowered to 10% - 20% comparing to the Rio Puerco SVC gain settings due to the weaker network strength at Guadalupe 345 kv station. 29

31 5 Conclusions and Recommendations PNM requested ABB to perform power flow and stability technical studies to increase the power injections on the BA-Blackwater 345 kv line (BB line) to the maximum level of 1000 MW. Previous technical studies of 832 MW power injection on the BB line have shown that a Static VAR Compensator (SVC) at the Guadalupe 345 kv station is necessary to provide the required voltage support to accommodate these power transfers. The 1000 MW BB line power injections for this study are: El Cabo wind farm at Clines Corner: 213 MW Broadview wind farm: 497 MW Taiban Mesa: 200 MW Aragonne Mesa: 90 MW The main conclusions from the study are as follows: 1. Powerflow contingency analysis showed that: Among all the contingencies, the highest post-contingency Guadalupe SVC susceptance reference is pu (1.0 pu Bref is 100 MVAr at nominal voltage, the post contingency Guadalupe voltage is about 1.019pu. As such, Qsvc is about 190 MVAr), for the double contingency of both BA-Rio Puerco 345 kv lines. No low voltage violations were identified. Minor high voltage violations occur post-contingency at the Broadview 345 kv station. These high voltages are related to set an initial voltage of pu at Broadview 345 kv based on the Broadview 297 MW PSCAD study. These violations can be ignored by modifying the voltage profile if required. For the double contingency of the BA-Rio Puerco 345 kv lines: o Overloads are identified on the BA 345/115 kv transformer and the 115 kv systems out of the BA 115 kv station. o Overload is identified on the El Cabo-BA 345 KV line. This line is fully loaded pre-contingency, with slight (2%) post-contingency overloads resulting from reduced post-contingency voltages. o A Remedial Action Scheme is planned for this contingency to trip the Taiban Mesa-Blackwater 345 kv line to maintain acceptable system performance, but was not modeled in the analysis. Overall, it can be concluded from the contingency analysis that no substantial violations occurred in the monitored areas and zones (Table 3-2). Thus an acceptable TPL performance is achieved. 2. Voltage stability margin based on QV analysis showed that: 30

32 Positive reactive margin is seen at Guadalupe 345 kv for all studied contingencies. With increased power injections on BB line, there is a significant decrease in the reactive margin but positive reactive margin is maintained for all normal and contingency conditions when the system is stressed 5% beyond the maximum transfer on the line. Additional VAR support is needed at the Guadalupe 345 kv station if voltages of 105% percent of nominal are desired under maximum loading. The Rio Puerco SVC shows relatively high capacitive output when Guadalupe voltage is at the low side. Overall, the QV analysis shows that for the analyzed outages, positive reactive margin is maintained at Guadalupe 345 kv in the voltage range of 0.95 to 1.05 pu. Thus the BB line transfer meets the WECC voltage stability margin criteria. 3. Dynamic simulation on the study base case with selected N-1 and N-2 contingencies showed that: Adequate system dynamic performance and adequate post-fault voltage recoveries are achieved. All the BB line wind power plants are able ride-through the studied faults. 4. Dynamic simulation on a sensitivity case with selected N-1 contingencies demonstrated that: With Blackwater HVDC in service with 15 MW E-W power level, system stability is maintained for all N-1 contingencies. All the BB line wind power plants and the Blackwater HVDC are able to ridethrough the studied faults The PSLF studies thus did not identify a need for additional voltage support beyond the Guadalupe SVC for the 1000 MW full buildout scenario. The system was found to meet the TPL criteria and the WECC voltage stability margin criteria. All the wind farms on the BB line were found able to ride through the studied faults with adequate post-fault voltage recoveries. However, the limitations of the positive sequence models used in this study cannot guarantee that a synchronous condenser at Blackwater station is not required to insure sufficient short 31

33 circuit capacity in the full buildout scenario for inverter based generation 2. PSCAD studies (3- phase model) are being performed in a separate study to evaluate whether a synchronous condenser at Blackwater station will be required to support the power injection conditions as stated above. 2 WECC White Paper: Value and Limitations of the Positive Sequence Generic Models of Renewable Energy Systems r%20generic%20model%20limitations%20december% docx&action=default&defaultit emopen=1 32

34 6 References [1] ITA - Broadview Full Buildout Affected System PSLF Study - Mar clean.pdf, ABB, March, [2] s from Brett Rollow of Pattern Energy, Monday, March 28, 2016 [3] Technical Data_125MVA_HICO, March [4] PNM Wind Data Request_Check List_Iberdrola docx, April [5] from PNM RE_ [External] RE_ Line impedance values for new 345 kv line at El Cabo, April 11, [6] ABB Technical Report E14417_0070_r0, Rio Puerco SVC PSLF Model, August [7] ABB Technical Report 1JNL , Blackwater HVDC Upgrade Project Main Circuit Parameters and Reactive Power Compensation, October,

35 7 Appendices Appendix A. Contingency Analysis Results, nominal load on BB line The voltage and thermal violations can be found in document: Appendix A.xlsx Voltage and thermal violations Appendix B. Dynamic Simulation Plots The dynamic simulation plots can be found in documents: Appendix B-1.pdf DYNAMIC SIMULATION PLOTS WITH GUAD SVC GAIN SETTING 1 Appendix B-2.pdf Dynamic simulation plots with Guad SVC gain setting 2, reduced Ki Appendix B-3.pdf Dynamic simulation plots with Guad SVC gain setting 3, reduced Ki Appendix C. Sensitivity Dynamic Simulation Results The sensitivity dynamic simulation plots can be found in documents: Appendix C-1.pdf Sensitivity case dynamic simulation plots with Guad SVC gain setting 1 Appendix C-2.pdf Sensitivity case dynamic simulation plots with Guad SVC gain setting 2, reduced Ki Appendix C-3.pdf Sensitivity case dynamic simulation plots with Guad SVC gain setting 3, reduced Ki 34