"1. The modular design of a electric breaker is proposed. A prototype of a solid-state circuit with an input voltage of 500 Vadjustable rated current including 50 A, 100 A, 150 A200 A. 2. Achieved zero-current cutoff within 110 µs using the characteristics of IGBTs to detect the current value. 3. A12 bits analog/digital converter is used to achieve a higher accuracy current detection effect when compared with the conventional analog circuit. It can also detect the fault current rising ratecorrespond to different protection delay times according to the different fault current rising rate, so that the components in the solid-state breaker can withstand a lower fault current."