Surge limiters for vacuum circuit breakers

Computer modeling was used to determine which applications require surge protection and to verify that surge limiters installed within the switchgear will provide this protection. The basic phenomena that cause vacuum switchgear related surges are reviewed, and the need for surge limiters is discussed. The design of these surge limiters is described, and information and performance data for their application are provided. It is concluded that modern vacuum circuit breakers with chromium-copper contacts do not require special considerations for most applications. Multiple reignitions and virtual chopping are potential low-probability problems under certain circuit conditions. Although this probability is low, the cost and downtime associated with a failure can be significant. Surge limiters can be easily installed within the switchgear to protect against this possibility. They provide protection comparable to surge arresters for rotating machinery protection and can be used to ensure that the motors or other loads are properly protected