DEMONSTRATION OF ESSENTIAL RELIABILITY SERVICES BY A 300-MW SOLAR PV POWER PLANT

DEMONSTRATION OF ESSENTIAL RELIABILITY SERVICES BY A 300-MW SOLAR PV POWER PLANT

CONTROL SYSTEM DESIGN

FIRST SOLAR PLANT CONTROL SYSTEM ARCHITECTURE Monitor conditions at the POI and compare them with the Set Points Send commands to inverters to make output adjustments and achieve POI requirements e - e - e - Grid Point of Interconnection (POI) e - Control Signal Voltage MW MVAR Closed Loop ~100 ms Cycles Electricity Flow e - e - e - 3

DEMONSTRATION OF ESSENTIAL RELIABILITY SERVICES BY A 300-MW SOLAR PV POWER PLANT 4

CAN VARIABLE ENERGY RESOURCES PROVIDE ESSENTIAL RELIABILITY SERVICES TO RELIABLY OPERATE THE GRID? NERC identified three essential reliability services to reliably integrate higher levels of renewable resources 1. Frequency Control 2. Voltage Control 3. Ramping capability or Flexible Capacity Test results demonstrated utility-scale PV plant has the capability to provide these essential reliability services Advancement in smart controls technology allows these plants to provide services similar to conventional resources VERs (Variable Energy Resources) with the right operating characteristics are necessary to decarbonize the grid 5 5

PV POWER PLANT DESCRIPTION First Solar PV modules 4 MVA PV inverters 9 x 40 MVA blocks 34.5 kv collector system Two 170 MVA transformers Tie with 230 kv transmission line PMUs collecting data on 230 kv side National Renewable Energy Laboratory 6

TESTING PROCESS Remote testing form First Solar operations center in Tempe, AZ: Supervision of testing activities Tracking plant performance Making changes in set points and plant control parameters Tempe, AZ San Bernardino County, CA National Renewable Energy Laboratory 7

SUMMARY OF CONDUCTED TESTS CAISO-NREL-First Solar custom-developed test scenarios: Regulation-up and regulation-down, or AGC tests during sunrise, middle of the day, and sunset Frequency response tests with 3% and 5% droop settings for over- frequency and under- frequency conditions Voltage and reactive power control tests Voltage control at near zero active power levels (nighttime control). Automatic voltage regulation at high and low power generation Power factor control Voltage limit control Volt-ampere reactive (VAR) control. National Renewable Energy Laboratory 8

AGC PARTICIPATION TESTS Morning 4-sec AGC signal provided to PPC 30MW headroom Tests were conducted for three resource intensity conditions (20 minutes at each condition): Sunrise Middle of the day Sunset Midday 1-sec data collected by plant PPC National Renewable Energy Laboratory 9

AGC TEST DATA ANIMATION #1 Morning AGC Test AGC set point Measured 30 MW National Renewable Energy Laboratory 10

AGC TEST DATA ANIMATION #2 Afternoon AGC Test AGC set point Measured 30 MW National Renewable Energy Laboratory 11

AGC PARTICIPATION TESTS - CONTINUED Afternoon The AGC test conducted during cloudy condition demonstrated similar AGC performance as for the previous cases. NREL 12

Regulation Accuracy of the PV Plant Exceeds Accuracy of Conventional Resources 13

VOLTAGE CONTROL: THIS TEST DEMONSTRATED THE PLANT S CAPABILITY TO CONTROL SYSTEM VOLTAGE By changing the reactive output of the plant from +100 MVAR to -100 MVAR, the voltage at the POI changed from 242 kv to 227 kv (Green curve) Page 14 14 14

SUMMARY OF CONDUCTED TESTS-FREQUENCY EVENTS IN THE WECC National Renewable Energy Laboratory 15

FREQUENCY DROOP TESTS 3% Frequency droop test (under-frequency) DDDDDDDDDD = PP/PP rrrrrrrrrr ff/60hhhh 3% and 5% under and over-frequency tests 20% headroom ±36 mhz dead band Actual frequency event time series measured in the U.S. Western interconnection 5% Frequency droop test (over-frequency) 16

REACTIVE POWER AND VOLTAGE CONTROL TESTS Active Power P-> 4MW Reactive Power Q 4.0 MVAR Proposed CAISO Reactive Capability for Asynchronous Resources GE ProSolar National Renewable Energy Laboratory 17

REACTIVE POWER AND VOLTAGE CONTROL TESTS Comparison of reactive power capability for a synchronous generator and PV Inverter Proposed CAISO Reactive Capability for Asynchronous Resources National Renewable Energy Laboratory 18

LAGGING AND LEADING POWER FACTOR CONTROL TESTS ±100 MVAR/min ramp rates applied PF limit = ±0.95 Tests conducted at nearly full power output 19

REACTIVE POWER CONTROL TEST Demonstrated ability of the plant to maintain capacitive and inductive VARs at the POI The plant was fully capable of following the reactive power set points with prescribed reactive power ramp rates. 20

LOW GENERATION REACTIVE POWER CONTROL TEST Plant was curtailed down to 5 MW output level Ability of the plant to produce or absorb VARs (±100 MVAR) was demonstrated 21

ACTIVE POWER CURTAILMENT TEST The curtailment control test was conducted to demonstrate the plant s ability to limit its active power production and then restore it to any desired level. The plant was accurately following the active power set point from nearly full production level to zero level with pre-set ramp rate of 30 MW/min. 22

ISO, NREL AND FIRST SOLAR CONDUCTED TESTS ON A 300 MW SOLAR PV PLANT TO DEMONSTRATE ITS OPERATING FLEXIBILITY Test Performance Ramping Ramp its real-power output at a specified ramp-rate Provide regulation up/down service Voltage Provide reactive power support in various modes - Control a specified voltage schedule - Operate at a constant power factor - Produce a constant level of MVAR - Provide controllable reactive support (droop setting) - Capability to provide reactive support at night Frequency Provide frequency response for low frequency and high frequency events - Control the speed of frequency response - Provide fast frequency response to arrest frequency decline 23 23