​By Lisa Meiman

In March, a multifunctional team completed construction on the first-ever variable shunt reactors to be installed at WAPA, improving reliability of the grid along sections of Sierra Nevada’s 230-kilovolt lines.

One variable shunt reactor each was installed at the Olinda and Elverta substations in California.

SN’s transmission system has experienced high voltages during light loading conditions, or light demand, because of the way the system is configured and connected to neighboring utilities.

High voltage can damage equipment and create instability in the grid. To prevent damage and outages, SN and its neighbors would control voltage using local generation units for the benefit of the system.

Over time, it became more challenging to use generating units to control voltage because of unit retirements and growth of renewable distributed generation, which can also result in high-voltage conditions during off-peak hours. WAPA conducted a study in 2013 that recommended installing shunt reactors at Olinda and Elverta substations to provide the necessary voltage control.

Construction began in August 2017 and was completed in March 2018, as scheduled and under budget.

“Smooth construction was possible due to better planning for equipment supplies, flexibility, dedication from our craft and engineers and good work quality of the selected construction contractor,” said Project Manager Zia Islam.

When energized in November, the variable shunt reactors will automatically adjust to optimize voltage  levels and sustain reliable energy delivery to customers.​

Shunt reactor

​A variable shunt reactor was installed at Elverta Substation in Sacramento County,
in March. (Photo by Zia Islam)

Last modified on September 12th, 2023