DWG Meeting March 7, 2017 (Update to a Meeting held July 26, 2016) Jin Zhu, ABB Jamie Austin, PacifiCorp Ron Schellberg, CPS Kevin Harris, Columbia Grid

Overview (today’s meeting focus) TEPPC 2026 CC V1.7 Load Issues Validating Load Profiles Station Service issue Pending Issues \ Questions Pmax (Power Flow vs. PCM)

Loads

CIPV 1/1/2026 CIVP 1/1/2026 Load Curve in the TEPPC 2026CC- V1.7 CIPV 1/1/2026 Load Curve, Actual – 2009 Yi Zhang found distortion when comparing the first several days, actual to hourly load profiles in V1.7. Jin asked if the staff started from the TEPPC 2024 loads, year prior, or from the Jan 1, 2009 hourly loads. If from the first, residual energy carried over may contribute to the distortion. Relative to BTM-PV modeling, the staff used allocation to area; this breaks down BTM-PV to the bus load weighted, based on load distribution factor.

The TEPPC 2026 CC Loads Developing the TEPPC Hourly Loads: Conforming Loads (Native Area Loads) Start with the BAA Area Forecast: Monthly Peak and Energy. Use the power flow case (base) or seasonal load distributions to allocate area load to the bus, based on bus load allocation ratio. Use a historic year actual hourly loads to develop the hourly forecast (e.g., 2009 in the TEPPC 2026CC). Nonconforming Load is the constant load throughout the simulation period (e.g., Station Service - SS, Industrial). Nonconforming loads are not part of bus load allocation ratio calculation Nonconforming load must be greater than bus load for base load and seasonal load distribution (Load forecast – output area load = total area nonconforming loads) Negative Loads are kept constant throughout the import\export process. They are assumed constant for all hours. Some generators are modeled as negative loads.

Fixing the Generator Discrepancy Adjust generation dispatch to reflect actual operation GV injects power proportionally to all distributed buses if defined as distributed generation 2X1 CC, modeled as a single CC plant, may start with GT1 and ST only, if the generation is below half of its capacity (GridView will assign generation to GT1, GT2, and ST proportionally) Hydro plant, modeled as single plant with distributed generators, may only start generators as its online capacity just above scheduled generation and scheduled reserves (GridView will commit all hydro units in the plant and assign generation proportionally) BTM generation assigned to load area, will be netted from area load The pumping loads in CAISO are modeled as negative generation in PCM (they cannot be netted from load as it varies differently with load profile). We need to adjust the power flow case to be consistent with PCM.

Fixing SS Load Discrepancy Three options to consider: First, if NO Station Service load: Remove nonconforming SS loads from “area level load assignment”, clean up load distribution with zeroing out SS nonconforming loads. Station Service load model: Adjust generator capacity to gross capacity consistent with power flow Pmax (current capacity in PCM is net capacity, consistent with heat rate capacity. Zero out all station service and negative loads in both bus load distribution (for all seasons) and area load assignment ("Adder(MW)"). Then, zero out any "Adders" IF t the adder is associated with a bus load (or sum of bus loads) which has/have TRUE "non-conforming" flag (NCF) but the total NCF bus loads change throughout the seasons (e.g., its 5MW in Summer but 2MW in Winter) .

Thermal Plant Pmax Plant Net Capacity = NQC (the total capability of a generating unit as demonstrated by actual operating or test experience less power generated used for auxiliaries and other station service) - modeled in PCM. Plant Gross Capacity = Plant Net Capacity + auxiliaries and other station service - modeled in power flow.

Managing SS, PCM & Power Flow Kevin Harris, Columbia Grid

Round-Trip and Station Service PF and PCM use different definition for modeled max rating PF: Pmax: Plant net capacity + auxiliaries and other station service load (SS) PCM: Max Rating: Net generation to the grid Issue: round trip requires the ability to move between PF ↔PCM Ideally: PF Pmax – PF SS = PCM Max Rating Problem how to we manage this data in the round-trip process and accommodate difference between PF and PCM?

PF to PCM PF to PCM PF Pmax: Store for later use PF SS: Storage for later use Status Flag: Store for later use PF Gen: Not used PCM Max: Rating: Net unit capability based on public source PCM: For island generation, turn on branches and busses to connect generation to the system

PCM to PF In a round-trip from PCM to PF three conditions exist: Condition 1a: PF: Yes and PCM Yes Pmax: Use stored value SS: Use stored value and set status flag to on Gen: Min(PCM Gen + PF SS, Pmax) Set Gen status flag to on

PCM to PF Condition 1b: PF: Yes and PCM No Pmax: Use stored value SS: Use Stored value and set status flag to off Gen: Use 0 Set Gen status flag to off Condition 2: PF: No and PCM Yes Gen: Min(PCM Gen, PF Pmax) Set Gen status flag to on

Identifying SS Load Highlights of identifying SS load from July 26, 2016 DWG call Problems found in identifying SS load WECC standard was not meet Area load starting with “S” SS load not starting with “S” and/or EPC: GE Long ID:= Start with “PPA” The estimated SS load modeled as a conforming load 54% (Should be non-conforming) Typically expect SS load on bus with generator at bus 92% SS Load with connected generator at bus 85%

Issues with SS Round-Trip Maintaining mapping of station service to generator for round-trip Not all SS load is a 1 (Gen) to 1 (SS Load) relationship Possible SS load combinations: 1 to 1, 1 to many, or many to 1 (like CC 3 to 1) Many entities do not follow WECC standard when defining station service load Load ID start with “S” EPC: GE Long ID:= Start with “PPA” Long term this cannot be achieved without SS load being identified and mapped in PF

Criteria for Station Service Station Service Load Exist if Criteria 0 and(Criteria 1 or Criteria 2) Criteria 0 (Station Service load exist): Load bus status: Closed And Bus load > 0: (MW + abs(Mvar)) > 0 And Criteria 1 (Adhere to EPC: GE Long ID definition of Station Service): EPC: GE Long ID:= Start with “PPA” Or Criteria 2 (Adhere to “ID” definition of Station Service): ID starts with “S” And EPC: GE Long ID:= Blank or “---” Resulting Station Service load (at 658 busses 4,884 MW) Conforming/Non-Conforming Load busses: 54%/46% With generator at bus 92% With connected generator at bus 85%

Modeled Gen During Round Trip PCM Modeled Modeled net rating (Source: EIA-860, NQC, HR…) On Export from PCM to PF Condition 1a: Generator is committed in both PF and PCM Pmax does not change Gen:= min(PCM gen + SS, Pmax) SS load is outputted to PF Condition 1b: Generator is committed in the PF but not PCM Pmax: does not change Gen:= 0 SS Load is not outputted to PF Condition 2: Generator is not committed in PF but is committed in PCM Gen:= min(PCM gen, Pmax) SS Load: does not exist