South West Power Link - Imperial Valley East

San Diego Gas and Electric Co. (SDG&E) is operating two series capacitors supplied by Hitachi Energy in their 500 kV South-West Power Link at Imperial Valley in Southern California. One series capacitor, Imperial Valley East, is rated at 372 Mvar at 500 kV system voltage. The other, Imperial Valley West, is rated at 519 Mvar at 500 kV system voltage. The series capacitors have replaced two older units, supplied by Hitachi Energy in the 1980s.

The purpose of installing the series capacitors was to increase the power transmission capability of the South-West power Link bringing power from the Palo Verde power plant up to the customer area of San Diego, thereby taking advantage of the inexpensive remote generation as compared to more expensive local generation in the San Diego area.

Promoting access to renewable energy
In 2012, a third Hitachi Energy series capacitor, rated at 976 Mvar, went on line at the Suncrest 525 kV s/s, as part of the Sunrise Powerlink Transmission Project. The Sunrise Powerlink transmission line is 120 miles long (190 km) and stretches from the Imperial Valley to San Diego. Its purpose is to provide access to electricity from renewable energy sources such as solar, geothermal and wind located in the Imperial Valley and eastern San Diego County. The line will also help reduce transmission congestion by strengthening the transmission grid and improving access to cheaper energy generated outside the region.

As the series capacitors are located in a seismically active area, an Hitachi Energy patented mechanical spring damper mechanism is incorporated in the platform design. All the equipment has been designed to meet the High Seismic Qualification level according to IEEE Standard 693.