Western Electricity Coordinating Council Renewable Energy Modeling Task

Western Electricity Coordinating Council Renewable Energy Modeling Task Force REMTF Report to MVWG Abraham Ellis, Sandia March 18, 2015 Salt Lake City, UT Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC 04 -94 AL 85000.

WECC REMTF Generic Models Approved (new), under development • Inverter-based (PV, WT 3/4 • WT 1/2 wind plants, storage) “Phase II” Module Use WTx. G Generator Module Use WTx. T Turbine REPC_A Plant controller WTx. P/A Pitch control/aero REPC_B Enhanced plant controller WT 2 E Rotor resistance REEC_A Electrical controls (Wind) REEC_B Electrical controls (PV) REEC_C Energy storage REGC_A Generator/Converter WTGT_A Drive Train WTGAR_A Aerodynamics WTGPT_A Pitch Control WTGTQ_A Torque Control • Distributed PV Module Use PVD 1 Discrete DG PVD 2 Enhanced discrete DG CMPLDWG Distributed generation All dynamic models except for CMPLDWG require explicitly generator representation in power flow

Generic Energy Storage Model

REEC_C: Energy Storage Module • Status: ü ü Specifications Testing Implementation MVWG technical spec approval ü Add to WECC AML

CMPLDWG: Distributed Generation • REMTF Recommendation/Request − Add hooks to allow different DG models (like PVDX) to be used with CMPLDWG

Update PVDX Model? Phase 3 Phase 2 Phase 1 CA SIWG and CA Rule 21 • Items REMTF will consider: § § Additional active power controls Add time dimension to trip functions Auxiliary input for other functionality Would become PVD 2

Wind/PV Plant Control Model

REPC_B: Enhanced Plant Controller • Adds new features § Interface with multiple WTGs § Interface with reactive support devices (MSC, SVC, synchronous condensers) § Plant level power factor control option • Expect approval item in June meeting

PV/Wind Model Updates • Good models, but the existing MDF is deficient – Many Wind/PV plants modeled as synchronous generators or loadnetted Example from 2022 LSP High Renewables Case used in WWSIS III study: • 18 GW modeled, 4. 5 GW modeled as genrou or motor 1, 2. 5 GW load-netted – Most of the PV/wind (Type 3/4) plants in the MDF are modeled as WTXX (models being phased out) or GEXX (not an approved model) – Almost none of the wind/PV data in the MDB has been validated, some considered suspect • How can the current situation improve? – Information (validation guidelines, workshops, etc. ) – Compliance enforcement with reasonable transition plan – Have patience

Wind Model Validation at BPA • BPA effort had mixed results • Technical assistance needed – Previous work by an REMTF member on similar BPA data produced better results

Model Validation Support • PV Plant Model Validation Guide under development – Document in late draft. Step-by-step procedure, example – Expect approval item in June meeting – Wind Plant Model Validation Guide is next • REMTF organizing a model validation webinar (June? Coordinate with SRWG workshop this summer? ) • What else can REMTF/MVWG do? Map 1 st Gen into 2 nd Gen?

REMTF Documentation • Technical specs, Application guides, Validation guides • Issue: updated documentation hard to find – Best way to handle would be a WECC. biz public folder • Recent IEEE papers (2015 PES GM)

WECC Plan to Transition to New REXX Models • Eric Bakie’s Report (separate presentation) – WECC model transition is underway, but it will not be completed by June 2015, as planned last year. • What else can be done? – Move milepost and increase pressure? – WECC to migrate 1 st Gen to 2 nd Gen models without changing the ? • Intermediate step until model validation requirement catches up • REMTF/MVWG could come up with parameter lookup tables; software developers could automate • May not create data ownership if done right (preserve response) • There may be other prickly issues – need to look into it carefully!!!

Limitation of Generic Models • Exploring numerical stability of positivesequence simulation programs with respect to very high penetration scenarios and low SCR – On-going research project at Sandia • REMTF white paper on RE model limitations