Relays are the logic elements of a protection system which sense the fault and cause the circuit-breaker trip circuits to be energized and the breakers to open their contacts.
继电器是保护系统的逻辑元件，它感知故障，并使断路器解扣电路带电和断路器打开触点。
2
After locating this fault, the circuit identifies the open wire and allows you to open and repair the correct cable end.
定位这个故障后，电路识别开路电线，允许断开和修复正常的电缆端。
3
Based on the analysis of main fault types of LV (Low Voltage) flameproof motor, the negative sequence protection principle is proposed for its asymmetric short circuitfault and open phase fault.