Sdg&e's Experience With Multiway Switchgear: Simplifying Protection and Control

Pad-mounted switchgear is rapidly gaining popularity in both industrial and distribution systems due to its compact design, enhanced safety features, and ease of installation. Traditional protection for switchgear has used multiple discrete relays to protect all load and source ways. Today, advancements in relaying capabilities allow a centralized protection and control (CPC) relay to protect all the load and source ways using a single device. A CPC provides benefits in terms of reducing the total number of devices and simplifies coordination between devices for protection or automation purposes. These coordinated functions often include applications like backup protection elements between ways, automatic source transfer schemes, synchronization of distributed energy resources, or islanding detection.

This paper highlights San Diego Gas and Electric’s (SDG&E) experience using a single device to protect multiway switchgear for several applications in their distribution system. These systems have been deployed widely and have provided over a decade of service for SDG&E. Their deployment of CPC relays with multiway switchgear eliminates the need for a separate remote terminal unit and includes logic to improve reliability with automatic power supply testing. The paper provides insight into how integrating these functions into a single device has allowed for standardization of processes, engineering, and testing, which has greatly simplified the deployment of switchgear for SDG&E.