Efficiency of Surge Arresters as Protective Devices Against Circuit-Breaker-Induced Overvoltages

The possible occurrence of transient overvoltages depends on the interaction between different components in a power system. In a cable system, circuit breaker (CB) operations may cause overvoltages, depending on the system configuration and the type of CB operations performed. Protective devices may be required during certain conditions. Surge arresters are a well-known product that could be applied. Surge arresters were originally developed as protection against lightning-induced overvoltages on overhead lines. However, they can also be used for protection against vacuum CB-induced transients in cable systems, and this is what the current publication reports on. Different surge arrester configurations were evaluated and two different surge arrester states are discussed; a “high current state” when the CB is closed and a high current passes through the surge arrester and a “low current state” when the CB is open and only a low current passes through the surge arrester. Finally, a new surge arrester configuration was evaluated and found to be advantageous in preventing amplification of internal resonances in the transformer.