Sylmar Electrode Design

Client: Los Angeles Department of Water and Power

The Los Angeles Department of Water and Power (LADWP) is proposing to replace the existing underground and marine electrode portions of the Sylmar Ground Return System (SGRS). The existing SGRS is an integral component of the Pacific Direct Current Intertie (PDCI) Transmission Line, which transmits bulk power between Los Angeles and the Pacific Northwest. The PDCI is a direct current (DC) system and cannot operate without a ground return system. Due to system age and deficiencies, LADWP is commissioning studies to determine the existing current capability and the enhancement needs of the PDCI ocean electrode system.

IEC is currently responsible for supporting LADWP on the study, permitting, and design of the Shoreline and Marine portion of the SGRS Project. Based on the approved design, IEC will then prepare a Request for Proposal (RFP) to provide services to procure and construct the DC electrode for the Sylmar Converter Station.

The Sylmar Ground Return System includes 31 miles of overhead lines, underground cables, and underwater cable segments that begin at the Sylmar Converter Station, the southern terminus of the PDCI. The major benefit of replacing the Sylmar Ground Return System is to ensure that the PDCI continues to operate reliably. The existing Ground Return System has not been upgraded since the original PDCI was first energized in 1970, even though the PDCI itself has been upgraded several times.