Slide 1: Eversource DER Level 3 ASO Study Preliminary Results
Eversource DER Level 3 ASO Study Preliminary Results Developers Update December 11th, 2020 Safety First and Always 1
Slide 2: Purpose of the Eversource Level 3 ASO Study
Purpose of the Eversource Level 3 ASO Study Ensure the proposed DER interconnection Projects will not in aggregate cause a significant adverse impact on the reliability and operating characteristics of the Eversource transmission system, the transmission facilities of another Transmission Owner, o
Slide 3: Western Massachusetts (WMA)
Western Massachusetts (WMA) Safety First and Always 3
Slide 4: DER Applications Aggregated by Substation in WMA
DER Applications Aggregated by Substation in WMA 5 DER applications totaling 19.3 MW applied for interconnection to the Eversource Distribution System in Western Massachusetts: – 3 applications totaling 12.3 MW at Blandford 19J – 1 application totaling 4.9MW at Partridge 15E – 1 application totali
Slide 5: Geographic Location of the Proposed DER Projects in the Eversource System in WMA
Geographic Location of the Proposed DER Projects in the Eversource System in WMA Safety First and Always 5
Slide 6: System Location of the Proposed DER Projects in the Eversource System in WMA
System Location of the Proposed DER Projects in the Eversource System in WMA Safety First and Always 6
Slide 7: WMA Steady State Base Cases
WMA Steady State Base Cases Steady state base cases representing study year 2023 included the following projects – Transmission Upgrades Westfield Reliability Project (Atwater Switching Station) Montague-Amherst Reliability Project (rebuild of Lines 1044, 1632, 1113, & 1134) – Relevant Group S
Slide 8: WMA Stability Base Cases
WMA Stability Base Cases NC stability base cases representing study year 2023 included the following projects – Transmission Upgrades Westfield Reliability Project (Atwater Switching Station) Montague-Amherst Reliability Project (rebuild of Lines 1044, 1632, 1113, & 1134) – Relevant Group Stud
Slide 9: Short Circuit Base Case
Short Circuit Base Case Short circuit base case was provided by ISO-NE that includes all relevant FERC interconnection projects in the study areas. Existing and PPA approved DERs between 1 MW and 5 MW were aggregated by distribution bus and modeled in the pre project short circuit base case. T
Slide 10: Preliminary Steady State Thermal and Voltage Results Summary
Preliminary Steady State Thermal and Voltage Results Summary The post-project N-1 and N-1-1 post-contingency thermal loadings met the Transmission System Planning criteria. The post-project N-1 post-contingency voltages met the Transmission System Planning criteria. Pre-existing N-1-1 high vol
Slide 11: Western MA 345-kV Voltage Issue (N-1-1)
Western MA 345-kV Voltage Issue (N-1-1) The 345-kV switchyard voltage at Agawam substation can rise higher than criteria for certain N-1-1 events with high East-West and New England-New York transfers. These post-event high voltages occur before the proposed DERs are included and are not made wo
Slide 12: Next Steps
Next Steps Complete study and issue final report to ISO-NE by end of December 2020 Obtain RC approval in January of 2021 Official ISO-NE PPA approval letters expected by end of January 2021 Safety First and Always 12
Slide 13: QUESTIONS?
QUESTIONS? Safety First and Always 13
Slide 14: Eastern Massachusetts (EMA)
Eastern Massachusetts (EMA) Safety First and Always 14
Slide 15: DER Applications Aggregated by Substation in EMA
DER Applications Aggregated by Substation in EMA ISO-NE Non-FERC Total # of Total Aggregate Export Queue # Substation Applications Limit (MW) A-Greater Boston 1 5.00 994 Burlington 391 1 5.00 B-Upper SEMA 45 164.10 992 Arsene St 654 2 7.00 1032 Bell Rock 661 3 11.99 993 Brook St 727 1 2.00 995 Canto
Slide 16: Geographic Location of the Proposed DER Projects in the Eversource System in EMA
Geographic Location of the Proposed DER Projects in the Eversource System in EMA Safety First and Always 16
Slide 17: System Location of the Proposed DER Projects in the Eversource System in EMA
System Location of the Proposed DER Projects in the Eversource System in EMA Stations with DER projects not shown on this diagram: Canton Burlington Safety First and Always 17
Slide 18: Steady State EMA Base Cases
Steady State EMA Base Cases Steady state base cases representing study year 2022 and 2025 – 2022 system topology with no FERC interconnections in SEMA. SEMA/RI upgrades with ISD after 2022 are excluded: Mid-Cape reliability project (new 115 kV Bourne - West Barnstable line) – RSP ID#1725 – ISD 1
Slide 19: Stability EMA Base Cases
Stability EMA Base Cases NC stability base cases representing study year 2022 and 2025 – 2022 system topology with no FERC interconnections in SEMA. SEMA/RI upgrades with ISD after 2022 are excluded: Mid-Cape reliability project (new 115 kV Bourne - West Barnstable line) – RSP ID#1725 – ISD 12/2
Slide 20: Short Circuit Base Case
Short Circuit Base Case Short circuit base case was provided by ISO-NE that includes all relevant FERC interconnection projects in the study area. Existing and PPA approved DERs between 1 MW and 5 MW were aggregated by distribution bus and modeled in the pre project short circuit base case. Th
Slide 21: Preliminary Steady State Results Summary
Preliminary Steady State Results Summary The post-project N-1 post-contingency thermal loadings met the Transmission System Planning criteria. Post-project N-1-1 overload on the 115 kV 191 line has been identified for 2025 summer peak, shoulder and light load, east-to-west stressed cases. Pre-
Slide 22: N-1-1 Thermal Overload in EMA
N-1-1 Thermal Overload in EMA The 115 kV 191-1 line (Auburn St. – Kingston) was found overloaded under N-1-1 conditions at various load levels in the 2025 system New Line as part of the topology. SEMA/RI Upgrades Addition of about 243MW of DER in SEMA and Cape caused this overload in system cond
Slide 23: High Voltage Issue in EMA in Minimum Load Cases
High Voltage Issue in EMA in Minimum Load Cases Pre-existing high voltage issues in Cape area were seen under N-1 and N-1-1 conditions in both 2022 and 2025 minimum load cases. Operations has also observed existing high voltage issues in the Cape area. Potential solution is to add reactive dev
Slide 24: Next Steps
Next Steps Complete all the steady state, stability and short circuit analyses by the end of December 2020. Issue final report of the Greater Boston area to ISO-NE by end of December 2020. Obtain RC approval for the project in Greater Boston area in January 2021. Official ISO-NE PPA approval
Slide 25: Complexity of PSCAD Study
Complexity of PSCAD Study Quality of the DER inverter PSCAD models: PSCAD models are more detailed than standard PSS/E models for stability analysis. They are usually developed by the inverter manufacturers and include proprietary information of the control systems. Not all PSCAD models are create
Slide 26: QUESTIONS?
QUESTIONS? Safety First and Always 26