1. ERS Forward Looking Measures 1, 2 & 4
Elena Melloni
Associate Engineer II, System Stability Planning
Western Electricity Coordinating Council

2. ERS Forward Looking Measures
1: Synchronous Inertia Response Under Minimum SIR Conditions
2: Rate of Change of Frequency (RoCoF)
4: Interconnection Frequency Response
Western Electricity Coordinating Council

3. Avg Dispatch (% of Cap), Weighted by Cap, Type, & Area
Case Creation
Target Renewable Capacity by Base Case Area
2021 Light Spring (21LSP1)
Adjustments
Renewable gen by BC Area based on latest PCM data
EPCL to adjust wind and solar based on turbine type
Redispatch gen to solve case
Baseload flags
DER netted with load
Simulated double PV outage
Avg Dispatch (% of Cap), Weighted by Cap, Type, & Area
Area WT
Solar PV
ALBERTA
40%
ARIZONA
41%
84%
B.C.HYDRO
20%
EL PASO
82%
IDAHO
62%
64%
IMPERIALCA
97%
LADWP
45%
94%
MEXICO-CFE
42%
80%
MONTANA
47%
NEVADA
86%
NEW MEXICO
46%
NORTHWEST
57%
50%
PACE
48%
63%
PG AND E
61%
90%
PSCOLORADO
37%
72%
SANDIEGO
91%
SIERRA
52%
SOCALIF
WAPA R.M.
49%
WAPA U.M.
Western Electricity Coordinating Council

4. Western Electricity Coordinating Council
Results
Highest Spread 230kV bus
MW 0.1Hz
500kV bus
MW 0.1Hz
IFRO for WI: 840 MW 0.1Hz
WI median: MW 0.1Hz
Western Electricity Coordinating Council

5. SIR Case Number Case Name Total System’s Synchronous Inertia (MVA*s)
Total Non-synchronous Generation Dispatched (Pgen [MW])
Total Synchronous Generation Dispatched (Pgen [MW])
Total DC Tie-Line Imports (MW) 
Total System Load (MW) 1
2021 Light Spring Scenario ORIGINAL
537526
8014
88653
-56
93746 2
2021 Light Spring Scenario ADJUSTED
497671
19813
77189
Western Electricity Coordinating Council

6. Western Electricity Coordinating Council
RoCoF
Resource Contingency Criteria (RCC) for WECC: 2740 MW
UFLS: 59.5 Hz
RoCoF 0.5 :
RoCoF RCC : -0.17
Western Electricity Coordinating Council

7. Interconnection Frequency Response
Performance Ratios
A:B (MW/.1Hz)
Adjusted:
Original:
A:C (MW/.1Hz)
Adjusted:
Original:
C:B (unitless)
Adjusted: 1.6
Original: 1.7
Time to UFLS: 0.343Hz
Western Electricity Coordinating Council

8. Looking Forward on the Forward Looking Measures
WECC would like to build a case using the Base Case Compilation process
More accurate & vetted data
Incorporate DER in the base cases
Track these measures to determine trends
Western Electricity Coordinating Council