Cargill Power Markets LLC Transmission Service Study (OASIS # TSR and )

Transcription

1 Cargill Power Markets LLC Transmission Service Study (OASIS # TSR and ) Prepared by: Electric Power Research Institute (EPRI) Under contract with: Public Service Company of New Mexico April 10, 2014

2 Foreword This report was prepared for Cargill Power Markets LLC by the Electric Power Research Institute, Inc., ( EPRI ) pursuant to a consulting contract with Public Service Company of New Mexico ( PNM ) Transmission Operations. This document was prepared by EPRI for PNM. Neither EPRI, PNM, any member of EPRI, any cosponsor, nor any person acting on behalf of any of them: (a) makes any warranty or representation whatsoever, express or implied, (i) with respect to the use of any information, apparatus, method, process, or similar item disclosed in this document, including merchantability and fitness for a particular purpose, or (ii) that such use does not infringe on or interfere with privately owned rights, including any party's intellectual property, or (iii) that this document is suitable to any particular user's circumstance; or (b) assumes responsibility for any damages or other liability whatsoever (including any consequential damages, even if EPRI or any EPRI representative or PNM or any PNM representative has been advised of the possibility of such damages) resulting from your selection or use of this document or any information, apparatus, method, process, or similar item disclosed in this document. Any correspondence concerning this document, including technical and commercial questions should be referred to: Director, Transmission/Distribution Planning and Contracts Public Service Company of New Mexico 2401 Aztec Road, Z220 Albuquerque, NM Phone: (505) Fax: (505) iii

3 EXECUTIVE SUMMARY This Transmission System Impact Study ( Study ) report documents technical studies performed by Electric Power Research Institute, Inc., pursuant to a consulting contract with Public Service Company of New Mexico ( PNM ) for Cargill Power Markets LLC ( Transmission Customer ). The study was performed in accordance with a Study Agreement between PNM and Transmission Customer executed on January 17, 2014 for Transmission Service Requests ( TSR ) and (studied as a single clustered MW and 100 MW). Transmission Customer requested 128 MW of long-term firm transmission service ( TSR ) on the PNM transmission system between the Blackwater 345 KV station point of receipt and the Four Corners switchyard 345 kv point of delivery in the Arizona Public Service ( APS ) Balancing Authority Area ( Transmission Path ). A portion of the Transmission Path for this transmission service will be transmitted on PNM s 216-mile, 345 kv transmission line between Blackwater and BA stations. Due to engineering considerations, a transmission line of this length can require that measures be taken to control the voltage profile along the length of the line. By way of example, control of voltage near the midpoint of the line required installation of line shunt reactors at the Guadalupe switching station when this line was first commissioned. The Blackwater to BA 345 kv transmission line is thermally limit at 1076 MW, but due to other limiting factors lack of voltage support and equipment limitations the line is limited to less than the line s thermal capacity. Based on current transmission service commitments, delivery of designated network resource, PNM has reached its full amount of capacity that it can commit of 662 MW (does not include line losses) on the Blackwater to BA 345 kv line. This 662 MW level was determined, by previous study work, to be due to a voltage stability limit (using a 5% margin from the all-lines in-service, N-0, limit). As such, it is anticipated, based on previous study analysis, that a static VAR compensator (SVC) at the Guadalupe station will be required to provide the required voltage support. Thus, PNM engaged Electric Power Research Institute, Inc., ( EPRI ) to determine the necessary transmission upgrades to provide firm transmission service to accommodate the 128 MW TSR at Blackwater 345 kv station for a total of 790 MW (does not include line losses) on the Blackwater to BA 345 kv transmission line. The steady-state and dynamic simulations have shown that in order to allow for an additional 128 MW of injection at Blackwater a significant amount of reactive support is needed, namely a +175 / -75 MVAr SVC at Guadalupe driven by essentially the loading on this long radial line. All voltage support devices from BA station and onwards into the PNM transmission system have negligible effect on the ability to support MW injections from the Blackwater end. The transmission system upgrades required to accommodate the TSR at full output are summarized in the table below. The corresponding costs, as estimated by PNM, and construction time estimates are provided.

4 Transmission System Upgrade Cost Construction ($M) Time SVC +175/-75 MVAr months Expand Guadalupe Station 345 kv for SVC interconnection (3 Breakers) months Replace BA and Blackwater wavetraps months Remedial Action Scheme (RAS) months Total months Guadalupe Station SVC One Line design v

5 CONTENTS 1 INTRODUCTION STUDY CRITEIRA Thermal and Voltage Criterion Transient Stability Performance Standard Voltage Stability MODELING ASSUMPTIONS System Modeling Steady-State Analysis Contingencies SIMULATION RESULTS Steady-State QV Analysis Steady-State PV Analysis Time-Domain Simulations CONCLUSIONS AND RECOMENDATIONS REFERENCES A QV AND PV PLOTS... A-1 B TIME-DOMAIN SIMULATION PLOTS... B-1 OASIS # TSR and vii

6 1 INTRODUCTION This Transmission System Impact Study ( Study ) report documents technical studies performed by Electric Power Research Institute, Inc. ( EPRI ), pursuant to a consulting contract with Public Service Company of New Mexico ( PNM ) for Cargill Power Markets LLC ( Transmission Customer ). The study was performed in accordance with a Study Agreement between PNM and Transmission Customer executed on January 17, Transmission Customer requested 200 MW of long-term firm transmission service ( TSR ) on the PNM transmission system between the Blackwater 345 KV station point of receipt and the Four Corners switchyard 345 kv point of delivery in the Arizona Public Service ( APS ) Balancing Authority Area ( Transmission Path ). The request is for a five-year term of service commencing January 1, 2012 and ending January 1, PNM was able to provide 172 MW of transmission service on the Transmission Path resulting in 28 MW that PNM could not accommodate. Transmission Customer also has the next in queue TSR for 100 MW (TSR ) of longterm firm transmission service on the same Transmission Path for a period of five (5) years commencing on January 1, 2012 and terminating on January 1, Transmission Customer requested the remaining 28 MW TSR and the 100 MW TSR be studied as a single clustered. A portion of the Transmission Path for this transmission service will be transmitted on PNM s 216-mile, 345 kv transmission line between Blackwater and BA stations. Due to engineering considerations, a transmission line of this length can require that measures be taken to control the voltage profile along the length of the line. By way of example, control of voltage near the midpoint of the line required installation of line shunt reactors at the Guadalupe switching station when this line was first commissioned. The total thermal capacity of the Blackwater to BA 345 kv transmission line is 1076 MW. It should be noted, however, that typically most high-voltage transmission lines, and certainly this line, are limited by other factors such as stability, equipment limitations, and voltage control which present a real limit lower than the line s thermal capacity. Based on current commitments for transmission service, delivery of designated network resource, PNM has reached its full amount of capacity that it can commit of 662 MW (does not include line losses) on the Blackwater to BA 345 kv line (see Figure 1-1 below). This 662 MW level was determined, under a previous study, to be voltage stability limited (using a 5% margin from the all-lines in-service, N-0, limit). OASIS # TSR and

7 Figure 1-1: Transmission commitments on the Blackwater-BA 345kV Line The objective of the Study is to determine the necessary transmission upgrades to provide firm transmission service to accommodate the additional 128 MW TSR at Blackwater 345 kv station for a total of 790 MW (does not include line losses) on the Blackwater to BA 345 kv transmission. Based on previous study analysis, a static VAR compensator (SVC) at the Guadalupe station will be required to provide the required voltage support. Thus, PNM engaged with EPRI to study this scenario and to determine the preliminary size for the voltage support device. This report is organized into the following sections: Section 2 provides the study criteria Section 3 provides a brief overview of the models used and modeling assumptions. Section 4 provides an overview of the simulations performed. Section 5 provides an overall summary of the conclusions and recommendations. The SVC size is based on the assumption that the 300 MW of total injection at Blackwater is a wind generator that utilizes either a type 3 or 4 technology with enough reactive capability to be able to maintain at least unity power factor at the point of interconnection at the Blackwater 345 kv interconnection. 1-2

8 2 STUDY CRITEIRA 2.1 Thermal and Voltage Criterion The steady-state performance criteria applicable to powerflow analysis in the DISIS are shown in Table 2. The criteria are NERC/WECC performance requirements as well as applicable additions and exceptions for the New Mexico transmission system. Table 1. Power Flow Performance Criteria Area Conditions Loading Limits Voltage (p.u.) Voltage Drop Application kV and above Artesia 345 kv EPEC (Area 11) PNM (Area 10) Arroyo 345 kv PST source side Alamo, Sierra Blanca and Van Horn Normal < Normal Rating kV % 60 kv to 115 kv % Artesia 345kV % Arroyo 345kV PST source side Alamo, Sierra Blanca and Van Horn kV Contingency < Emergency Rating % Hidalgo, Luna, or other 345 kv buses 46 kv and above* Normal ALIS < Normal Rating ^ 6 %** 46 kv to 115 kv Contingency N-1 < Emergency Rating ^ 6 %** 230 kv and above Contingency N-2 < Emergency Rating ^ 10 % 46 kv and above* Normal ALIS < Normal Rating All buses Tri- State (zones ) % Contingency N-1 < Emergency Rating % Contingency N-2 < Emergency Rating % All buses 69 kv and above except Northeastern NM and Southern NM 69 kv and above in Northeastern NM and Southern NM *Taiban Mesa and Guadalupe 345 kv voltage 0.95 and 1.1 p.u. under normal and contingency conditions. **For PNM buses in southern New Mexico (Zones 104,130, 131, and 132), the allowable N-1 voltage drop is 7%. ^ Provided operator action can be utilized to adjust voltages back down to 1.05 pu All equipment loadings must be below their normal ratings under normal conditions the emergency ratings for both single and double contingency conditions. Additional reactive power support may also be required to comply with the stability performance criteria. 2.2 Transient Stability Performance Standard The NERC/WECC transient stability performance requirements for transmission contingencies are as follows: All machines will remain in synchronism. All voltage swings will be well damped. OASIS # TSR and

9 Following fault clearing for single contingencies, voltage on load buses may not dip more than 25% of the pre-fault voltage or dip more than 20% of the pre-fault voltage for more than 20 cycles. For N-2 and breaker failure contingencies, voltage on load buses may not dip more than 30% of the pre-fault voltage or dip more than 20% of the pre-fault voltage for more than 40 cycles Fault clearing times used in this study are shown in Table 3. Table 2 PNM Fault Clearing Times Fault Type Voltage (kv) Clearing Time (near-far end breakers) Cycles Cycles Cycles 3 Phase Normally Cleared Fault Type 1 Phase Stuck Breaker Voltage Clearing Time (normally opened breaker both near and far (kv) end breaker opened due to stuck breaker both near and far end Cycles Cycles 2.3 Voltage Stability The voltage stability limit will be determined by the maximum reactive margin (QV) and maximum loadability (PV). The voltage stability limit is defined as the maximum transfer MW value at 0 MVAr margin for V-Q analysis or 0 MW margin for P-V analysis divided by 1.05 for n-1 outages. 2-2

10 3 MODELING ASSUMPTIONS This section gives an account of the models used and the modeling assumptions made for the analysis presented in section System Modeling The following WECC models were provided by PNM as a starting point for the study: 1. rev-bc.sav the powerflow case 2. typ2015hw_01.dyd the corresponding dynamics data for the powerflow case Both files were provided in GE PSLF TM format. For this work GE PSLF TM version was used. The base case powerflow is shown in Figure 2-1. In order to prepare the case for the study the following modifications were taken: The collector model for the Transmission Customer 172 MW Wind Turbine Generators ( WTGs ) at Blackwater 345 kv was slightly refined to reflect a typical expected collector system for a wind power plant of that size, namely: 1. Assuming 118, 1.5 MW wind turbine generator (WTG) at 1.67 MVA each 2. Assuming each WTG step-up transformer to be 1.75 MVA with an impedance of j pu 3. Assuming the collector system to be j / j 0.08 pu on 100 MVA (this is based on appropriately scaling the equivalent collector model from Taiban Mesa) 4. Assuming an 8% on 100 MVA substation-transformer with an X/R ratio of This wind power plant is assumed to have a power factor capability of +/ pf at the turbines and to hold close to unity power factor at the point of common coupling without controlling the voltage. The turbines were assumed to be type 3 WTGs. 6. The typical Low Voltage Ride Through ( LVRT") settings for the GE 1.5 MW WTGs was assumed for the units (the same as for Taiban Mesa). Adding the Additional 128 MW Injection: For the proposed additional 128 MW injection at Blackwater, a second WTG power plant composed of MW WTGs in parallel to the existing WTGs was simulated The same modeling assumptions are used as for the original 172 MW injection. The additional 128 MW were dispatched against the San Juan generation. The case with this additional injection is shown in Figure 3-2 note, an SVC at Guadalupe is required to solve the all-lines-in-service case. Important Note: Presently, the major manufacture of type 2 WTGs has ceased to offer this product anymore to the international market. Furthermore, type 1 WTGs although still sold by OASIS # TSR and

11 several vendors, in general, are not being deployed in either the North American or European markets. As such, the analysis here is based on a type 3 WTGs with constant power factor control. It is extremely important to realize that the results here are highly dependent on these assumptions. Should the customer in the end decide to go with type 1 WTGs it is almost certain that a second dynamic reactive device such as a large SVC or STATCOM will be required by the Transmission Customer as part of the WTGs facilities. 3.2 Steady-State Analysis Analysis was performed to determine the maximum reactive margin (QV) and maximum loadability (PV) the acceptable voltage stability limits. For the purposes of the QV analysis the same models as discussed above were used. For the purposes of the PV analysis the following assumptions were made: 1. Real power was injected in increments of 5 MW (i.e. 5 MW, then 10 MW, etc.) at unity power factor (i.e. 0 MVAr for all injection levels) at the Blackwater 345 kv bus. 2. The PNM swing bus at San Juan (near Four Corners) was allowed to absorb the injected power so that the power is essentially being transferred from Blackwater, through BA to the Four Corners area. 3.3 Contingencies PNM currently uses single-pole switching to allow the BA to Blackwater 345 kv line to remain in service for temporary single-phase-to-ground faults. From a transient stability perspective this is a much less severe event than 3-phase faults at the BA end of the BA Norton or BA Rio Puerco lines and tripping of those lines. Furthermore, 3-phase faults on the BA Blackwater line (certainly on the portion between Taiban Mesa to Blackwater) will lead to clearing of the line and tripping of all elements (generation and HVDC) on the line, since these devices cannot operate in an island with no load and large amounts of MW injection. Thus, these scenarios were not investigated. However, it should be understood that Transmission Customer is responsible for ensuring adequate islanding protection to transfer trip all the turbines in the wind power plants following such a scenario to avoid damage of their equipment under an islanding scenario and potential consequential damage to the transmission equipment. Thus, the main transmission contingencies that are likely to be onerous for the proposed MW injection at Blackwater are: 1. BA to Rio Puerco 345 kv 2. BA 345/115 kv Transformer 3. BA to Norton 345 kv 4. Rio Puerco West Mesa 345 kv 5. Rio Puerco San Juan 345 kv 6. Rio Puerco Four Corners 345 kv These are the contingencies that were focused on in this study. 3-4

12 Figure 3-1: Base case powerflow. OASIS # TSR and

13 Figure 3-2: Powerflow case including the New Wind plant of 128 MW at Blackwater. 3-6

14 4 SIMULATION RESULTS The results of the steady-state and dynamic simulations are reported in this section. Note: The BA to Blackwater 345 kv line has wavetraps installed at the BA and Blackwater stations. These series devices have a continuous rating of 717 MVA (1200 A). These devices would need to be replaced to handle the additional 128 MW power injection at Blackwater. The analysis here assumes this change. 4.1Steady-State QV Analysis QV analysis was performed first to look at the reactive margin at both Guadalupe and Blackwater 345 kv substations for the all-lines in-service (N-0) and the four N-1 scenarios listed in section 3.3. The QV plots are provided in Appendix A. The results are summarized in Table 4-1. From these results the following can be discern: 1. The amount of reactive support needed would be slightly less at Blackwater as compared to Guadalupe. 2. The base case (with 172 MW of injection at Blackwater) is only marginally stable for many of the outages out of Rio Puerco. In fact a simple power flow solution attempt will show that the case diverges and is thus very close to instability. 3. To achieve the required 300 MW injection at Blackwater at least 127 MVAr of injection at Guadalupe is required to maintain stability, and at least 155 MVAr to maintain a reasonable voltage profile on the BA-Blackwater line. This is based on the worst outage (Rio Puerco to San Juan RP-SJ or Rio Puerco to West Mesa RP - WM). 4. For the Rio Puerco to San Juan outage (RP-SJ) the QV curve at Blackwater has quite a high-voltage nose. That is, instability occurs around 1.05 pu. This suggests that regulating voltage for this scenario with a reactive supporting device at Blackwater may be more difficult. Table 4-1: Results of QV analysis. A negative margin means that the case is stable and has those VArs in reserve, while a positive number means the case in unstable and requires that many VArs to acquire a solution. Guadalupe 345 kv (172 MW injection at BW) Guadalupe 345 kv (300 MW injection at BW) Contingency Reactive Margin Reactive Margin Reactive Need for 1.04 pu Voltage N MVAr 111 MVAr 147 MVAr BA - RP 0 MVAr 124MVAr 156 MVAr BA 345/115 TX -3 MVAr 121 MVAr 155 MVAr BA - NR 0 MVAr 125 MVAr 160 MVAr RP - WM -4 MVAr 120 MVAr 154 MVAr RP - SJ 0 MVAr 127 MVAr 155 MVAr RP - FC 3 MVAr 116 MVAr 144 MVAr Blackwater 345 kv (172 MW injection at BW) Blackwater 345 kv (300 MW injection at BW) Contingency Reactive Margin Reactive Margin Reactive Need for 1.04 pu Voltage N MVAr 87 MVAr 100 MVAr BA - RP 0 MVAr 102 MVAr 112 MVAr BA 345/115 TX -2 MVAr 98 MVAr 108 MVAr BA - NR 0 MVAr 109 MVAr 111 MVAr RP - WM -2 MVAr 95 MVAr 106 MVAr RP - SJ 0 MVAr 143 MVAr 147 MVAr RP - FC 2 MVAr 100 MVAr 108 MVAr 4-7

15 4.2 Steady-State PV Analysis The WECC planning criteria for voltage stability [1] requires that the loading level of an interface be no more than 95% of the collapse point of the PV curve for the worst N-1 outage. In this present case under study this translates to the following: all else remaining the same, the amount of MW injected at Blackwater that can be served is 95% of the value which will cause divergence of the powerflow solution under the worst N-1 outage condition. Thus two PV scenarios were simulated: 1. Starting with the base case the Transmission Customer plant was removed and instead a generator was used at the Blackwater 345 kv bus with zero MVAr output. The MW output of this generator was incrementally increased (in 5 MW increments) until the system powerflow solution diverged for each of the four N-1 contingencies in section 3.3. The PNM area swing, San Juan, absorbed the power injection, thus the power was transferred from Blackwater to the Four Corners area. 2. Ran the same case above, this time with a +175 / -75 MVAr SVC at Guadalupe. The simulation results are shown in Appendix A. The goal of this study is to determine the reactive compensation need at Guadalupe to accommodate the 128 MW TSR at Blackwater 345 kv station for a total of 790 MW (does not include line losses) on the Blackwater to BA 345 kv transmission line. As mentioned above the actual MW injection capability is equal to 95% of the value at which the PV curve diverges that is a powerflow solution is no longer achievable. The PV plots in Appendix A thus show two dashed vertical lines on each plot: 1. A dashed red line that represented the desired injection level; 172 MW without the SVC at Guadalupe and 300 MW with the SVC 2. A dashed magenta line at 95% of the PV nose, based on the WECC criteria The worst outage is the Rio Puerco West Mesa 345 kv line; based on the PV results. For this outage, based on the WECC criteria, based on steady-state analysis, for a total of 300 MW of injection at Blackwater, in addition to the existing 200 MW from the HVDC, and with the additional 90 MW of injection at Guadalupe and 200 MW at Taiban Mesa (for a total MW injection of 790 MW at BA, excluding losses) a +175 MVAr voltage support device is needed at Guadalupe. Based on the dynamic simulations, and operating experience of PNM, this reactive supporting device needs to be a smoothly controlled shunt reactive compensation device. To achieve true smooth control the device needs to be a static var compensator (SVC) with a thyristor controlled reactor (TCR). SVCs that incorporate only thyristor switched capacitors are not capable of smooth vernier control, they are discrete devices. Furthermore, if a TCR based SVC is to be implemented then it makes sense from an operational stand point to include some inductive range for potential overvoltage conditions during light load scenarios and when the wind power plant is off-line. The marginal cost of this additional inductive range is minimal since the TCR is needed anyway for smooth regulation. For outage of the SVC, there would not be enough time for operator intervention to curtail transfers on the BA to Blackwater 345 kv line. A Remedial Action Scheme (RAS) will be required to trip the Guadalupe to Blackwater 345 kv line, to alleviate all stability problems 4-8

16 associated with the SVC outage. Powerflow analysis confirms this result and a time domain simulation also demonstrates this result as shown in the next section. It should be noted that an SVC solution at Blackwater was not considered. Although, the QV analysis showed that a slightly smaller amount of reactive compensation might be needed at Blackwater, none-the-less, the more technically sound location appears to be Guadalupe. The reason for this is twofold: 1. As indicated in the QV analysis results for at least one of the cases the nose of the QV curve is at a very high-voltage (1.05 pu), which is indicative of voltage instability at highvoltages and thus difficultly regulating voltage with a reactive supporting device at Blackwater. 2. With an SVC at Guadalupe the overall BA to Blackwater 345 kv line voltage profile is much better than with the SVC at Blackwater. This is illustrated by the steady-state powerflow solutions shown in Figures 4-1 and 4-2, respectively. In these figures the voltage profile on the line is shown for one of the worst contingencies (Rio Puerco to West Mesa) for the case of the SVC being placed at the two alternative locations. Clearly, for the case of the SVC at Guadalupe the voltage profile across the line is better and more flat (i.e. roughly the same from BA to Blackwater). 4-9

17 Figure 4-1: Steady-state solution for new wind case (i.e. 300 MW injection at Blackwater) with an SVC at Guadalupe and a Rio Puerco to West Mesa 345 kv line out of service. 4-10

18 Figure 4-2: Steady-state solution for new wind case (i.e. 300 MW injection at Blackwater) with an SVC at Blackwater and a Rio Puerco to West Mesa 345 kv line out of service. 4-11

19 4.3Time-Domain Simulations Time domain simulations were performed on the base case (i.e. no SVC at Guadalupe and 172 MW of injection from Transmission Customer generator at Blackwater) and the new wind injection case (i.e / -75 MVAr SVC at Guadalupe MW of injection from wind power plants at Blackwater). Two outages were simulated, namely the BA to Norton 345 kv and the Rio Puerco to West Mesa 345 kv line outage. The latter was determined to be the worst outage from the PV analysis. A total of six simulations (pre- and post-128 MW injection) were performed, as follows: 1. Outage of BA to Norton 345 kv line with a 3-phase fault at the BA side, fault clears in 4 cycles. 2. Outage of Rio Puerco to West Mesa 345 kv line without a fault, just opening the line. 3. Outage of Rio Puerco to West Mesa 345 kv line with a 3-phase fault at Rio Puerco, fault clears in 4 cycles. For the SVC at Guadalupe the svsmo1 model [2], which is the latest WECC approved model for SVCs, was used. Typically parameters were used for the SVC settings. For now it was assumed that the SVC does not have a slow-susceptance regulator or coordinated MSC/MSR switching. However, should this device be pursued such additional features would be prudent and can be easily added. At the very least the SVC can be designed to automatically control the shunt reactors at Guadalupe. The results of the simulations are shown in Appendix B. Table 4-2 summarizes the results. It can be seen clearly that the addition of the SVC ensures stability up to the 300 MW injection level. Consider Figure 4-1. In this figure is shown the 345 kv voltages at BA, Guadalupe, Rio Puerco and Blackwater for four (4) different simulations: 1. With the SVC in-service blue line, 2. The SVC is tripped at 1 second red dashed-line, 3. The SVC is tripped at 1 second and the line from Guadalupe to Blackwater (and all connected equipment) is tripped 12 cycles later black dashed-line 4. As above (case 3) with the additional action that the 65 MVAr shunt reactor at Guadalupe is switched in with the RAS magenta dashed-line. All these cases are with at the 300 MW injection level at Blackwater 345 kv station. What can be observed from the figure is as follows: The case with the SVC is stable and flat. Once the SVC trips the case is unstable. When the SVC trips the line becomes unstable (red dashed-line); however, by tripping the entire Guadalupe to Blackwater 345 kv line in this case we are able to ensure stability for the rest of the system. This is why a RAS scheme is needed to trip the line in the event of the loss of the SVC. In the case with the RAS implemented, the final steady-state voltage at Guadalupe is slightly high (above 1.05 pu). However, this can be easily remedied, if desired, by switching in one of the Guadalupe shunt reactors at the same time as switching out the 4-12

20 Guadalupe to Blackwater 345 kv line. This is illustrated by the last simulation shown by the magenta dashed-line. Figure 4-3: Simulations for (i) blue line with SVC, (ii) red dashed-line SVC tripped, (iii) black dashed-line SVC tripped and RAS implemented, and (iv) magenta dashed-line SVC tripped, RAS implemented, and one Guadalupe reactor switched in

21 Table 4-2: Results of time-domain simulations Wind MW Total MW Injection at Injection at Clearing Case Name Blackwater BA Disturbance Fault Time System Response bcbr3p BA - Norton 345 kv BA 4 cycles System is stable bcrw Rio Puerco - West Mesa 345 kv no fault N/A System is stable bcrw3p Rio Puerco - West Mesa 345 kv RP 4 cycles System is stable bcnwsvcbr3p BA - Norton 345 kv BA 4 cycles System is stable bcnwsvcrw Rio Puerco - West Mesa 345 kv no fault N/A System is stable bcnwsvcrw3p Rio Puerco - West Mesa 345 kv RP 4 cycles System is stable 4-14

22 5 CONCLUSIONS AND RECOMENDATIONS Presently, PNM has committed 626 MW of transfer capability on the Blackwater to BA 345 kv line, with 200 MW injected by the HVDC at Blackwater, 90 MW injected at Guadalupe by the Aragonne Mesa wind power plant, 200 MW injected at Taiban Mesa by the Lone Mesa wind power plant and 172 MW of injection at Blackwater by the Transmission Customer project. The purpose of this study was to determine the necessary transmission upgrades to provide firm transmission service to accommodate the 128 MW of injection at Blackwater. The analysis has shown that in order to allow for a further 128 MW of injection at Blackwater a significant amount of reactive support is needed, namely a +175 / -75 MVAr SVC at Guadalupe driven by essentially the loading on this long and radial line. All voltage support devices from BA station and onwards into the PNM transmission system have negligible effect on the ability to support MW injections from Blackwater. The SVC size is based on the assumption that the 300 MW of total injection at Blackwater will come from wind generation that utilizes either a type 3 or 4 technology with enough reactive capability to be able to maintain at least unity power factor at the point of common coupling at the 345 kv interconnection. It should also be noted that the STATCOM at Argonne Mesa wind power plant exhibits some somewhat strange behavior during the course of system dynamic response, in all the cases, which leads to some rather large voltage swings at that wind power plant. It s unclear if this is real (i.e. the control strategy of the device is truly so erratic) or it is a problem with the user-written model. There are two other insights that may be gleaned from a perusal of the results and a careful look at the steady-state and dynamic response of the BA Blackwater line: There are many dynamic devices on this line. The HVDC at Blackwater, which has an ac voltage control loop. The wind power plant at Taiban Mesa, which regulates the voltage at Taiban Mesa using the GE WindVAR system. The shunt reactors at Guadalupe. The STATCOM at Argonne Mesa. The eventual new wind power plants at Blackwater, and finally the proposed new SVC at Guadalupe. All these devices are also trying to in one way or another regulate voltage on the same line, admittedly at different points of the line. This is thus very complicate system. It is essential that a close look be taken at ensuring that all these devices are properly coordinated and a clear operating strategy is put into place on how to coordinate the voltage set-point on all these devices so that they do not fight each other nor lead to unintended consequences. Three of the four sources of MW injection on the line are from wind power plants. This clearly means that the MW levels on the line are continuously varying. As such, a smoothly controllable device such as an SVC is much more preferable than discretely switched capacitor banks for the reactive support at Guadalupe. This is because operationally the SVC can automatically regulate itself as the wind power levels go up and down hourly and daily, as opposed to constantly switch devices in and out all day and thereby causing excessive wear on the switching devices. Furthermore, switched devices may not be fast enough to response following severe disturbances. 5-1

23 If even more MW injection is sought in the future at Blackwater, a serious consideration should be given to having two coordinated dynamic reactive support devices (e.g. SVCs) at Guadalupe and Blackwater, and allowing those two devices to solely control and regulate the voltage at these points. This would markedly simplify the operational aspects of voltage regulation on the line, as well as be more technically sound since once the MW injection goes significantly higher it is not feasible to assume that a larger device at Guadalupe will be capable of ensure proper voltage regulation at Blackwater where the MWs are being injected. The transmission system upgrades required to accommodate the TSR at full output are summarized in Table 5-1 below. The corresponding costs, as estimated by PNM, and construction time estimates are provided. Table 5-1 Transmission System Upgrades Transmission System Upgrade Cost Construction ($M) Time SVC +175/-75 MVAr months Expand Guadalupe Station 345 kv for SVC interconnection (3 Breakers) months Replace BA and Blackwater wavetraps months Remedial Action Scheme (RAS) months Total months Guadalupe Station SVC One Line design A-5-2

24 6 REFERENCES [1] WECC Voltage Stability Criteria, Undervoltage Load Shedding Strategy, and Reactive Power Reserve Monitoring Methodology, Approved April 28, 2010; %20Stability%20Criteria%20-%20Guideline.pdf [2] Generic Static Var System Models for the Western Electricity Coordinating Council, April 18th, Documents/GenericStaticVarSystemModelsforWECC.pdf 6-1

25 A QV AND PV PLOTS QV Plots Base Case 172 MW Injection at Blackwater: A-1

26 A-2

27 A-3

28 A-4

29 QV Plots New Case with 300 MW total Injection at Blackwater: A-5

30 A-6

31 A-7

32 PV Plots Base Case 172 MW Injection at Blackwater: A-8

33 A-9

34 A-10

35 PV Plots New Case with 300 MW total Injection at Blackwater: A-11

36 A-12

37 A-13

38 A-14

39 B TIME-DOMAIN SIMULATION PLOTS B-1

40 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

41 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

42 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

43 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

44 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

45 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

46 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

47 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

48 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

49 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

50 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

51 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

52 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcnwsvcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

53 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcnwsvcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

54 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcnwsvcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

55 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt NEW_WIND SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcnwsvcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

56 Time( sec ) Bsvc GUADLUPE v Qsvc GUADLUPE v vr GUADLUPE v SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on B-A-Norton 345 kv line at B-A 345 kv; Trip B-A-Norton 345 kv line in 4 cycles. bcnwsvcbn3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

57 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

58 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

59 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

60 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt NEW_WIND SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

61 Time( sec ) Bsvc GUADLUPE v Qsvc GUADLUPE v vr GUADLUPE v SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

62 Time( sec ) vbug B-A vbug GUADLUPE vbus WESTMESA vbus RIOPUERC vbug BLACKWTR vbug TAIBANMS SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

63 Time( sec ) pg LONEMS pg ARGONNEG pg TRANS_WIND paci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

64 Time( sec ) qg LONEMS qg ARGONNEG qg TRANS_WIND qaci SPS EQ SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

65 Time( sec ) vt LONEMS vt ARGONNEG vt TRANS_WIND vt NEW_WIND SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07:

66 Time( sec ) Bsvc GUADLUPE v Qsvc GUADLUPE v vr GUADLUPE v SPP 2000SC MODEL. 2001CASE 8/14/ Winter Post-project Case 3-Phase fault on Rio Puerco-West Mesa 345 kv line at RP 345 Trip Rio Puerco - West Mesa line in 4 cycles bcnwsvcrw3p.chf Page 1 C:\MyProjects\PSAS\PNM Wed Mar 26 01:07: