Electricity Markets

CAISO gets OK to require equipment upgrades for renewables


The California Independent System Operator has received approval from federal energy regulators to require equipment improvements for renewable energy generators on the grid, which will pave the way for increased integration of wind and solar power, CAISO reported on July 16.

The Federal Energy Regulatory Commission in early July approved tariff revisions filed by the ISO aimed at preventing temporary and sporadic losses of inverter-based generation plants connected to the ISO- controlled power grid.

CAISO said that the FERC action follows recommendations by a task force formed by the North American Electric Reliability Corp. (NERC) in response to an August 2016 event when smoke from the Blue Cut Fire tripped 500-kilovolt (kV) and 220 kV transmission lines in Southern California causing nearly 1,200 megawatts of solar energy to unexpectedly go offline.

The "first known major loss of utility-scale solar resources" occurred in California on Aug. 16, 2016, as the result of a transmission system disturbance initiated by a fire-induced fault, NERC noted in a 2017 Summer Reliability Assessment. Smoke from the Blue Cut wildfire in San Luis Obispo County resulted in the tripping of two 500-kV lines in the active fire area, the report said.

FERC’s approval will now require inverter-based generator resources to inject reactive current during low-voltage conditions to allow for a minimum delay for frequency tripping and a quick return to support the bulk power system reliability, CAISO said.

FERC’s order also requires inverter-based generators greater than 20 MW in size to record and store data for all frequency and voltage events to assist any future investigations by the ISO and transmission owners.

The July 2 FERC order is available here.