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.