March 2017 to June 2017 Preliminary Interconnection Cluster Window System Impact Study 49.9 MW IA-PNM May 2018

Transcription

1 March 2017 to June 2017 Preliminary Interconnection Cluster Window System Impact Study 49.9 MW IA-PNM May 2018 Prepared by: Public Service Company of New Mexico

2 Foreword This report is prepared for customers who submitted a Large Generator Interconnection Application during the March 2017 to June 2017 Preliminary Interconnection Cluster Window. The request was submitted on June 5, 2017 and assigned the queue number IA-PNM This study was performed by the Public Service Company of New Mexico (PNM) Transmission/Distribution Planning and Contracts Department. Neither PNM, any cosponsor, nor any person acting on behalf 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 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: Thomas Duane Manager of Transmission Planning Public Service Company of New Mexico 2401 Aztec Road NE, MS-Z220 Albuquerque, NM 87107

3 Table of Contents Executive Summary... 1 Introduction... 5 NERC Compliance Considerations... 5 Study Criteria... 5 Generator Reactive Power Range Criterion... 6 Voltage Ride-Through Requirement... 6 WECC Over/Under Frequency Standards... 7 Power Flow Criteria... 7 Transient Stability Criteria... 8 Short Circuit Criteria... 9 Power Flow Base Case Development... 9 Project Model Generation Dispatch List of Contingencies Reactive Power Analysis Power Flow Analysis Summer Peak Non- Peak Network Upgrades Power flow Voltage Performance Results Short-Circuit Analysis Results Transient Stability Analysis Results Cost and Construction Time estimates Table of Figures Figure 1 IA-PNM Project Location... 1 Figure 2- IA-PNM (NR) Project Illustration... 2 Figure 3 IA-PNM (NR) Project and Gen-tie Figure 4 IA-PNM (NR) Project Power Flow Model Figure 5 Revised Britton Station with Network Upgrades Figure 6 Algodones Switching Station Re-Build... 16

4 Figure 7 Pre-Project Peak Case Figure 8 Pre-Project Non-Peak Case Figure 9 Post-Project Peak Case Figure 10 Post-Project Non - Non Peak... 23

5 Table of Tables Table 1 Generator Off-Nominal Frequency Operation Guide... 7 Table 2 Power Flow Disturbance/Performance Criteria... 7 Table 3 PNM Fault Clearing Times... 8 Table 4 Generation Dispatch Table 5 Reactive Power Capability at the POI Table 6 Heavy Summer Post Project Overloads with No Network Upgrades Table 7 Non Peak Post Project Overloads with No Network Upgrades Table 8 Britton to Algodones Option Table 9 Britton To Sandia Option Table 10 Britton Station upgrades of Network Upgrade options above Table 11 Option 1 plus Britton Network Upgrades... 18

6 Executive Summary PNM received a single Large Generator Interconnection Application during the Preliminary Interconnection Cluster Window which opened in March 2017 and closed on June This report focuses primarily on the system impacts in the area of the interconnection request referred to as the Soaring Solar Project, and has been assigned queue number IA-PNM The facility will interconnect to the Britton 115 kv switching station and has a planned generating capacity of 49.9 MW. The proposed in-service-date is June 01, The customer has requested the project be studied as a Network Resource. Britton and PNM s surrounding transmission system are shown below in Figure 1 below. POI Figure 1 IA-PNM Project Location The purpose of this interconnection cluster study was to identify the feasibility of interconnection and provide a high-level assessment of the system reinforcements required to safely and reliably interconnect Soaring Solar generating facility as a network resource. The project location and surrounding PNM transmission system are shown below in Figure 2. Page 1

7 Figure 2- IA-PNM (NR) Project Illustration The findings of the Preliminary Interconnection System Impact Study (PISIS) are summarized as follows: Steady-State Performance The power flow analysis shows that the following network upgrades are required to accommodate the Network Resource interconnection for IA-PNM : Construct a new line from the Britton 115 kv Switching Station to the Algodones 115 kv Switching Station. Add one additional breaker to the Britton Switching Station to connect the Soaring Solar project. Re-build the Algodones 115 kv Switching Station Page 2

8 Transient Stability Performance March 2017 to June 2017 Preliminary Interconnection Cluster Window: System Impact Study The transient stability analysis had acceptable system performance for all single contingencies studied. Ultimately the Interconnection Customers will have to verify that the Project can meet or exceed PNM interconnection requirements. Short Circuit Analysis Based upon previous analysis with resources in this area, a short circuit analysis was not deemed necessary because existing short circuit capacity is expected to be adequate. If this project decides to proceed to a Definitive Interconnection System Impact Study ( DISIS ) the need for a short circuit analysis will be re-evaluated. Reactive Power Analysis The reactive power analysis indicates that IA-PNM will need a minimum of 5.1 MVAr of supplemental reactive power support at the 34.5 kv station transformer bus to achieve a +/ net power factor range at the high side of the Station transformer. This is based on a gross aggregate Project generation of 50.4 (53 MVA) with 49.9 MW delivered to the POI. The deficiency could be met in full or part with various options including increasing the reactive range of the inverters, installing shunt capacitors or increasing the range of the Battery Energy Storage ( BES ). Should the project be submitted to a DISIS, reactive power capability will be reaffirmed. This analysis only provides an indication of reactive power requirements and it remains the Interconnection Customer s responsibility to design their generation facilities and additional supplemental reactive support, if needed, to meet the requirements at the POI. Page 3

9 Cost and Construction Time Estimate March 2017 to June 2017 Preliminary Interconnection Cluster Window: System Impact Study The cost estimate and schedule for the Network Upgrades for IA-PNM are summarized below: SYSTEM UPGRADE Network Upgrades Required Expand ring bus by adding one breaker to create an open bay position. Construct a new line from Britton Switching Station to Algodones Switching Station COST ($M)* CONSTRUCTION TIME months months Re-build Algodones switching Station from a single breaker scheme to a five (5) breaker ring bus months Total months * This is only a planning estimate. Detailed cost estimate would come in a Facilities Study once a Definitive Interconnection System Impact Study has been performed. This estimate assumes that a new control house structure at Algodones, along with a moderate estimate for right of way for the new transmission line. Estimated construction time assumes appropriate outages can be obtained to meet timelines. Page 4

10 Introduction This PISIS report documents the results of an analysis to determine the physical and electrical impacts to PNM s transmission system for interconnection of the Soaring Solar Generation Facility. It also provides general information on potential Network Upgrades, certain Customer obligations, and operating procedures, if needed, to accommodate the interconnection request. The results of this study are based on power flow (thermal and voltage) analysis.. This PISIS reviews IA-PNM as a Network Resource as requested by the customer. The purpose of the Network Resource analysis is to identify the Network Upgrades required for Network Interconnection Service. Interconnection Service, in and of itself, does not convey Transmission Service. This PISIS also provides a non-binding cost and construction schedule estimate for all identified system reinforcements required for the Network Resource interconnection. NERC Compliance Considerations This study will be used as evidence for compliance with North American Electric Reliability Corporation (NERC) standard FAC which requires transmission planners and owners, amongst other entities, to study the impact of interconnecting new or materially modified facilities on the Bulk Electric System. The standard addresses the following study requirements for new or modified interconnections: 1. The reliability impact of the new interconnection, or materially modified existing interconnection, on affected system(s); 2. Adherence to applicable NERC Reliability Standards; regional and Transmission Owner planning criteria; and Facility interconnection requirements; 3. Steady-state, short-circuit, and dynamics studies, as necessary, to evaluate system performance under both normal and contingency conditions; and 4. Study assumptions, system performance, alternatives considered and coordinated recommendations. While these studies may be performed independently, the results shall be evaluated and coordinated by the entities involved. To address these requirements, the study and associated study report will: Identify the affected systems and reliability impact and the study report will include statements to that effect; Include statements on the applicable NERC Reliability Standards and documentation of other guiding criteria; Identify inclusion of each study type (steady state, dynamic, short circuit) or why a specific category is not included; and Include assumptions, evidence and discussion of system performance, discussion of alternatives or why alternatives are not included and include statements on coordination with other entities documenting the relevant information obtained through coordination. Study Criteria A system reliability evaluation consists of power flow analysis for identifying thermal overloads or voltages outside criteria (too high or low) under normal and contingency conditions. Transient stability analysis is performed to ensure all machines remain in synchronism, all voltage swings are damped, and Page 5

11 all frequency dips are within acceptable limits. A short circuit analysis is performed to ensure all fault currents remain within acceptable circuit breaker and switch capabilities. Each evaluation is conducted for credible contingencies that the system might sustain, such as the loss of a single or double circuit line, a transformer, a generator or a combination of these facilities. Planning analysis is conducted sufficiently in advance of potential interconnection, so that network upgrades or modifications can take place in time to prevent a reliability criteria violation. This study was completed in accordance to NERC Standard FAC Performance of the transmission system is measured against the following planning criteria: the Western Electricity Coordinating Council (WECC) Reliability Criteria, and the North American Electric Reliability Council (NERC) Planning Standards. If system reliability problems resulting from the interconnection of a project are discovered, the study will identify the system facilities or operational measure that will be necessary to mitigate reliability criteria violations. Addition of these new facilities would maintain the reliability to the transmission network. This DSIS investigates whether the interconnecting cluster results in: Equipment overloads on transmission lines, transformers, series compensation or other devices Voltage criteria violations All machines remain synchronized to the transmission system Voltage and frequency swings exceed acceptable limits Fault duty increases that result in short circuit current that exceeds the interrupt rating of circuit breakers and switches Generator Reactive Power Range Criterion All generators that seek to interconnect to the PNM transmission system must comply with certain reactive power requirements 1. The required power factor range is determined by the power factor test summarized below: Base cases are constructed with the purposed generation in-service. The reactive power range at full output and control capability described in the interconnection application are represented in the case with generation enabled. A power flow simulation is conducted to determine whether each generating unit can provide a ± 0.95 power factor range the high side of the Station transformer. If a unit cannot provide the ± 0.95 power factor at the Station transformer, then supplemental reactive power support to achieve a ± 0.95 power factor range at the Station transformer shall be required. Voltage Ride-Through Requirement Generators connected to the PNM transmission system are required to meet the low voltage ridethrough (LVRT) requirements contained in WECC s PRC-024-WECC-CRT-0-Low Voltage Ride-Through Criterion 2. In this case, IA-PNM is expected to ride through (i) a three-phase fault, cleared in normal time and (ii) a single-line-to-ground fault with delayed clearing at the POI on the Britton to Algodones 115 kv 115 line or Britton to Willard 115 kv line. 1 See PNM FAC-001-R VOLTAGE LEVEL AND MW/MVAR CAPACITY OR DEMAND 2 For TPL , TPL-002-0a, TPL-002-0b, TPL-003-0a, TPL see NERC website Page 6

12 It should be noted that positive-sequence, reduced-order simulation models do not allow for a detailed evaluation of voltage ride-through. The interconnection studies only provide an indication of risk and it remains the Interconnection Customer s responsibility to design their generation facilities to meet the ride-through requirement. WECC Over/Under Frequency Standards Generators connected to the PNM transmission system are required to meet the WECC under/over frequency requirements as shown in Table 2 below 3. These requirements should be reviewed with the equipment manufacturer for projects that plan to interconnect to PNM s Transmission system. Table 1 Generator Off-Nominal Frequency Operation Guide Under Frequency Limit Over Frequency Limit Minimum Time 5 >59.4 Hz < 60.6 Hz N/A (continuous operation) 59.4 Hz 60.6 Hz 3 minutes 58.4 Hz 61.6 Hz 30 seconds 57.8 Hz 7.5 seconds 57.3 Hz 45 cycles 57.0 Hz 61.7 Instantaneous trip 5 Minimum Time is the time the generator should stay interconnected and producing power. Power Flow Criteria All power flow analysis is conducted with version 21.1_02 of General Electric s PSLF/PSDS/SCSC software. Traditional power flow analysis is used to evaluate thermal and voltage performance of the system under Category A (all elements in service), Category B (N-1) and Category C (N-2) conditions. 4 The power flow performance criteria utilized to assess the impact of the interconnecting cluster throughout the PSIS are shown in the table below. The criteria are WECC/NERC performance requirements 5 with applicable additions and/or exceptions for the New Mexico transmission system 6. Table 2 Power Flow Disturbance/Performance Criteria AREA CONDITION LOADING LIMIT EPEC (Area 11) PNM (Area 10) Tri- State Zone VOLTAGE RANGE (p.u.) VOLTAGE DEVIATION APPLICATION Normal ALIS (P0) < Normal Rating NA BES facilities P1 < Emergency Rating % 5 BES facilities P2-P7 < Emergency Rating NA BES facilities Normal ALIS (P0) < Normal Rating NA BES facilities P1 < Emergency Rating % BES facilities P2-P7 < Emergency Rating NA BES facilities Normal ALIS (P0) < Normal Rating NA BES facilities P1 < Emergency Rating % BES facilities 3 See PRC-006-WECC-CRT-1 Attachment A: Off-Nominal Frequency Load Shedding Plan page 11 item 12 4 For TPL , TPL-002-0a, TPL-002-0b, TPL-003-0a, TPL see NERC website 5 For TPL-001-WECC-1-CR, TPL-002-WECC-1-CR, TPL-003-WECC-1-CR, TPL-004-WECC-1-CR see 6 For PNM exceptions to WECC criteria see Page 7

13 AREA CONDITION LOADING LIMIT VOLTAGE RANGE VOLTAGE (p.u.) DEVIATION APPLICATION ( ) P2-P7 < Emergency Rating NA BES facilities 1) Taiban Mesa 345, Guadalupe 345 kv, Clines Corners 345 kv, and Jicarilla 345 kv voltages and 1.10 pu under normal and contingency conditions 2) PNM will monitor 46 & 69 kv facilities 3) El Paso will monitor 69 kv facilities 4) Greenlee 345 kv is an 8% voltage drop All equipment loadings must be below their normal ratings under normal conditions. All line loadings must be below their emergency ratings for both single and double contingencies. All transformers and equipment with emergency ratings should be below their emergency ratings. Transient Stability Criteria 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. Following fault clearing, the voltage shall recover to 80% of the pre-contingency voltage within 20 seconds of the initiating event for all P1 through P7 events, for each applicable BES bus serving load. Following fault clearing and voltage recovery above 80%, voltage at each applicable BES bus serving load shall neither dip below 70% of pre-contingency voltage for more than 30 cycles nor remain below 80% of pre-contingency voltage for more than two seconds, for all P1 through P7 events. Fault clearing times are shown in Table 4 Ensure low voltage ride through on all faults. Fault clearing times used in this DISIS are shown in Table 3. Table 3 PNM Fault Clearing Times Categories Fault Type Voltage Clearing Time (near-far end breakers) (kv) 3 Phase Cycles P1,P3,P6 Normally Cycles Cleared Cycles Categories Fault Type Voltage (kv) 1 Phase 345 P2,P5,P7 Normally 230 Cleared Categories Fault Type Voltage (kv) 1 Phase 345 P4 Stuck 230 Breaker Clearing Time (normally opened breaker both near and far end breaker opened due to stuck breaker both near and far end 4-4 Cycles Cycles Clearing Time (normally opened breaker both near and far end breaker opened due to stuck breaker both near and far end 4-16 Cycles Cycles Page 8

14 Short Circuit Criteria Breakers in excess of 92% are flagged for determination as to when the breaker should be considered for upgrading. Generally based on age and maintenance related issues those in excess 95% are to be scheduled for upgrade. Power Flow Base Case Development The approved WECC 2018 heavy summer case is used to develop the PNM 2018 summer peak power flow base case, while the WECC 2018 heavy winter case is used to develop the PNM 2018 off-peak power flow base case. The approved WECC 2017/18 heavy winter case ( HW2) was used to develop the PNM 2018 non-peak power flow base case. Details of the generation dispatch and resulting path/transmission element flows, and bus voltages of interest are discussed below. The off-peak base case includes a forecast with very light Central New Mexico Electric Cooperative loads which are served from the 115 kv lines in the Britton area. The case represents the most restrictive scenario for generation export since there is lower load offsetting the generation. Page 9

15 Project Model Specific modeling parameters for queue IA-PNM were provided by the customer in the interconnection application. The parameters are used to construct the power flow model. The Point of Interconnection (POI) is located at the Britton 115 kv switching station. The Project connects to the POI through a generator tie line and a step-up transformer with the expected Britton station additions show in Figure 3. The power flow model with the step-up transformer and generator tie line is depicted below in Figure 4. Figure 3 IA-PNM (NR) Project and Gen-tie Page 10

16 Figure 4 IA-PNM (NR) Project Power Flow Model Generation Dispatch The generation dispatch of existing and planned facilities for each case used for this PSIS are itemized in the table below. Page 11

17 Table 4 Generation Dispatch Coal UNIT NAMEPLATE RATING (S/W) PEAK PRE-PROJECT HEAVY SUMMER PEAK POST-PROJECT NON-PEAK PRE-PROJECT NON PEAK NON-PEAK POST-PROJECT San Juan Unit San Juan Unit 2(retired) San Juan Unit 3(retired) San Juan Unit 4 (Area Swing) Four Corners Unit 1 (retired) Four Corners Unit 2 (retired) Four Corners Unit 3 (retired) Four Corners Unit Four Corners Unit Natural Gas Existing Reeves Existing Reeves Existing Reeves Existing Delta-Person Existing Luna Energy Facility Existing Lordsburg Existing Afton Existing Valencia Energy Facility Proposed Delta-Person Expansion Existing La Luz # Proposed La Luz# Proposed Reeves Re-Power Project San Juan Gas Plant Wind Resources Existing Taiban Mesa Wind Project Existing Aragonne Mesa Wind Project Existing Red Mesa Wind Project Existing High Lonesome Mesa Project Existing Broadview/Grady Wind Project Proposed Granada Wind Project Proposed La Sierrita Wind Farm 70 0** 0** 0** 0** Proposed Mountainair Wind Project 100 0** 0** 0** 0** Proposed Dunmoor Wind Project 700 0** 0** Proposed Taiban Mesa II Project Solar Resources Existing Ambrose Solar Project Existing Reeves Solar Project Existing Los Lunas Solar Project Existing Manzano Solar Project Existing Marquez Solar Project Existing Meadowlake Solar Project Existing Prosperity Energy Storage (Studio) Solar Project Proposed Arabella Solar Project 300 0** 0** 0** 0** Proposed Enchanted Mesa Solar Proposed Los Morros Solar Project Proposed South Valley (South Coors) Solar Proposed Lost Horizon 1 Solar Project Proposed Lost Horizon 2 Solar Project Proposed Tome Solar (VIA) Project Proposed Valencia Solar Project Proposed Route66 Solar Project Page 12

18 Britton Solar Project Rio Puerco Solar Project Other/Resource Combinations Proposed Torrance Biomass Project Proposed Geothermal Project Project Under Study Soaring Solar Project 49.9 n/a 49.9 n/a 49.9 List of Contingencies Power Flow Contingencies NO. CATEGORY CONTINGENCY DESCRIPTION Category P0 Contingencies 0 P0 All-lines-in service Category P1 Contingencies 345 kv 1 P1 Line B-A-Rio Puerco 345 kv 2 P1 Line San Juan-Cabezon 3 P1 Line Cabezon-Rio Puerco 4 P1 Line Four Corners-Rio Puerco 345 kv 5 P1 Line WestMesa-Rio Puerco 6 P1 Line West Mesa-Arroyo 345 kv 7 P1 Line West Mesa-Sandia 345 kv 8 P1 Luna-Macho Springs 9 P1 Transformer Rio Puerco 345/115 kv 10 P1 Transformer B-A 345/115 kv 11 P1 Transformer SANDIA 345/115 kv 12 P1 Transformer LUNA 345/115 kv 13 P1 Line Rio Puerco-Veranda 115 kv 14 P1 Line Algodone-Pachman 115 kv 15 P1 Line Britton-Willard 115 kv 16 P1 Line Belen-Tome 115 kv 17 P1 Line Belen-Los Morros 115 kv 18 P1 Line Los Morros-West Mesa kv 19 P1 Line Belen-Socorro 115 kv 20 P1 Line Kirtland-Person 115 kv 21 P1 Line Kirtland-Sandia 115 kv 22 P1 Line North-Richmond 115 kv 23 P1 Line Prager-Richmond 115 kv 24 P1 Line Person-West Mesa kv 25 P1 Line Person-Valencia 115 kv 26 P1 Line Valencia Solar-El Cerro 115 kv 27 P1 Line El Cerro-College 115 kv 28 P1 Line College-Tome 115 kv 29 P1 Line Person-West Mesa kv 30 P1 Line Prager-West Mesa kv 31 P1 Transformer Person 115/46 kv 32 P1 Transformer Tome 115/46 kv 33 P1 Line Person Tome 115 kv PB 34 P1 Transformer Britton 115/12.47 kv 35 P1 Line Rio Puerco-B-A 345 kv 36 P1 Line Pachman-B-A 115 kv Page 13

19 NO. CATEGORY CONTINGENCY DESCRIPTION 37 P1 Line Algodone-Pachman 115 kv 38 P1 Line Rio Puerco-Pachman 115 kv 39 P1 Line Britton-Algodones 115 kv 40 P1 Line Belen-Willard 115 kv Transient Stability Contingencies NO. CATEGORY CONTINGENCY DESCRIPTION CLEARING TIME (CYCLES) Category P0 Contingencies 0 P0 No Disturbance run n/a Category P1 Contingencies 1 P1 BRITTON ALGODONES 115 kv 3-phase fault near BRITTON 115 kv 4 2 P1 BRITTON WILLARD 115 kv 3-phase fault near BRITTON 115 kv 4 Reactive Power Analysis The IA-PNM project was tested in the over-excited and under-excited direction and the required reactive power requirement is enforced at the POI. Table 5 Reactive Power Capability at the POI Direction POI Capability POI Required POI Surplus/Deficiency Over-Excited 11.3 MVAR MVAR -5.1 MVAR Under-Excited MVAR MVAR 0 MVAR In the overexcited state, there is a reactive power deficiency of 5.1 MVAR. This can be rectified at the customer s discretion by increasing reactive capacity on the solar inverters, adding a switched capacitor at the collector system substation or other additions to increase reactive capability. In the under-excited state, the facility is sufficient to meet the power factor requirement at the point of interconnection. Power Flow Analysis This study models the interconnection of the IA-PNM solar generating facility while supplying 49.9 MW at the POI in both the summer and winter base cases. All forty (40) outages were simulated in the Heavy Summer and non-peak cases. Summer Peak Review of the thermal results identified two project related Category P1 overload. This is shown in Table 6. Page 14

20 Table 6 Heavy Summer Post Project Overloads with No Network Upgrades Post Project No Network Upgrades # Branch/Element Contingency Description Pre Post 1 BRITTON ALGODONES 115 kv Line BELEN WILLARD 115 kv line HUNING RANCH BELEN 115 kv Line HUNING RANCH LOS_MORR 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line LOS_MORR - SANCLEMT 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line SANCLEMT - BELEN_PG 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line Item #2 the Huning Ranch Belen 115 kv line has been identified in Cluster 8 Definitive Interconnection System Impact Study ( DISIS ) as being overloaded. The upgrade cost is, therefore, not determined or included in this analysis. It is shown here for informational purposes to note that the upgrade is needed if the Cluster 8 projects do not move forward. Non- Peak A review of the thermal results identified two project related Category P1 overload. This is shown in Table 7 Non Peak Post Project Overloads with No Network Upgrades Post Project No Network Upgrades # Branch/Element Contingency Description Pre Post 1 BRITTON ALGODONES 115 kv Line BELEN WILLARD 115 kv line HUNING RANCH BELEN 115 kv Line HUNING RANCH LOS_MORR 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line LOS_MORR - SANCLEMT 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line SANCLEMT - BELEN_PG 115 kv Line Ckt 1 BRITTON ALGODONES 115 kv Line Item #2 the Huning Ranch Belen 115 kv line has been identified in Cluster 8 Definitive Interconnection System Impact Study ( DISIS ) as being overloaded. The upgrade cost is, therefore, not determined or included in this analysis. It is shown here for informational purposes to note that the upgrade is needed if the Cluster 8 projects do not move forward. Network Upgrades Network upgrades will be needed for the Belen - Willard 115 kv line outage to address overloads of the Algodones-Britton 115 kv line. The following solutions were considered for this analysis: A second Algodones Britton 115 kv line that parallels the existing line. A new 115kV line from Britton to Sandia. A new 115 kv line from Britton to Diamond Tail 345 kv switchyard. Britton Switching Station will require an additional breaker to accommodate the additional line. This is shown in Figure 5. Page 15

21 Figure 5 Revised Britton Station with Network Upgrades Algodones Switching Station where the line terminates with the second Algodones - Britton alternative will have to be completely rebuilt as a ring bus to meet PNM switching station requirements. The layout of this is shown in 6. Figure 6 Algodones Switching Station Re-Build Page 16

22 The Britton Diamond Tail alternative was not modeled because of the complexity of its interaction with the B-A to Blackwater wind farms and could be considered later should this project continue on to a DISIS. The B-A to Blackwater line has some complex Remedial Action Schemes that will have to be revaluated if this alternative is pursued. The remaining two alternatives were placed into the power flow and were evaluated for their performance for mitigating the Belen Willard 115 kv line outage. Both alternatives were found to adequately mitigate overloads of the Britton-Algodones line. Power flow Voltage Performance Results The voltage analysis focused on Areas 10, 11, and 14, and on voltages 46 kv and above. Review of the voltage results did not identify any Cluster generated violations. Short-Circuit Analysis Results Based upon previous analysis with resources in this area, a short circuit analysis was not deemed necessary because existing short circuit capacity is expected to be adequate. If this project decides to proceed to a Definitive Interconnection System Impact Study ( DISIS ) the need for a short circuit analysis will be re-evaluated. Transient Stability Analysis Results The transient stability analysis showed acceptable system performance for all single (P1) contingencies studied. Further dynamic analysis will be performed if this project moves to a DISIS cluster. Page 17

23 Cost and Construction Time estimates March 2017 to June 2017 Preliminary Interconnection Cluster Window: System Impact Study The Network Upgrades for IA-PNM are summarized below. The corresponding cost and construction time estimates are shown for each upgrade. This is only a planning estimate. Detailed cost estimates would come in a Facilities Study once a Definitive Interconnection System Impact Study has been performed. Estimated construction time assumes appropriate outages can be obtained. Table 8 Britton to Algodones Option 1 Britton-Algodones Network Upgrade Cost Construction Time Transmission Line $ million 40 months Algodones Terminal $ million 18 months Total $ 39.0 M$ 40 months Table 9 Britton To Sandia Option 2 Britton-Sandia Network Upgrade Cost Construction Time Transmission Line $ 34 million 60 months Sandia Terminal $ 1.75 million 18 months Total $ M$ 60 months Table 10 Britton Station upgrades of Network Upgrade options above. Britton Station Upgrades Network Upgrade Cost Construction Time Bay and Bus Work $ 1.25 million 18 months Additional Breaker $ 0.75 million 18 months Total $ 2.00 million 18 months Table 11 Option 1 plus Britton Network Upgrades SYSTEM UPGRADE Britton to Algodones plus Britton Station upgrades Expand ring bus by adding one breaker to create an open bay position. Construct a new line from Britton Switching Station to Algodones Switching Station COST ($M) CONSTRUCTION TIME months months Re-build Algodones switching Station from a single line single breaker to a five (5) breaker ring bus months Total months Page 18

24 Appendix A One-line Diagrams Page 19

25 Figure 7 Pre-Project Peak Case Page 20

26 Figure 8 Pre-Project Non-Peak Case Page 21

27 Figure 9 Post-Project Peak Case Page 22

28 Figure 10 Post-Project Non - Non Peak Page 23

29 Appendix B Stability Plots Page 24

30 Figure 11: PSLF Pre-Project Flat Run Page 25

31 Figure 12: PSLF Pre-Project Algodones-Britton Outage Run Page 26

32 Figure 13:PSLF Pre-Project Britton-Willard Outage Run Page 27

33 Figure 14: PSLF Post-Project Flat Run Page 28

34 Figure 15: PSLF Post-Project Algodones-Britton Outage Run Page 29

35 Figure 16: PSLF Post-Project Britton-Willard Outage Run Page 30