Solid-State Trip Circuit Breakers in Navy Electrical Power Systems

An investigation was made of the suitability of solid-state trip circuit breakers as substitutes for electromechanical circuit breakers in Navy electrical power systems. Two types of tests were conducted ambient temperature was varied to determine its effect on the time-versus-current curve, and a salt-fog environment was simulated to determine its effect on the physical behavior of the circuit breakers. The effect of temperature on the time-versus- current characteristics was negligible the characteristics were still within the manufacturers specified tolerance for this temperature range. The results of these temperature tests indicate that the solid-state circuit breakers are superior to the molded-case circuit breakers for installation where high ambient temperatures prevail or where coordination of protective devices is important. The salt-fog tests showed that the electronic trip units are more vulnerable to failure in a heavy salt-laden environment than the trip units of electromechanical circuit breakers.