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Case Study

HVDC convertor stations

San Francisco, Golden Gate Bridge

Advisian was awarded the contract to provide engineering services for the high voltage direct current (HVDC) terminals for the Trans Bay Cable Project, a 53 mile submarine transmission line that stretches under the San Francisco Bay from Pittsburgh, California, to San Francisco.

The Situation

The Trans Bay Cable project is one of a family of projects approved by the California Independent System Operator (CAISO) to ensure reliable transmission capacity to the San Francisco area. The project provided for the transfer of 400 MW of power from Pittsburgh, CA, to San Francisco via a 53-mile submarine HVDC transmission line that stretches under the San Francisco Bay. This plus and minus 200 kV HVDC transmission line provides a dedicated connection between the East Bay and San Francisco and helped meet the City of San Francisco’s projected electrical demand for 2010 and beyond.

Siemens utilized their new high-voltage, direct-current (HVDC) Plus technology for this application; it was the first application worldwide. This technology is the preferred solution where shortage of space is a factor.


The project scope relating to the HVDC terminals included site engineering, electrical and structural engineering, permit management, and environmental compliance services. 


Our effort on this project was recognized through a “2010 Western Council of Construction Consumers Distinguished Project award.”