选用原则： (1)根据线路对保护的要求确定断路器的类型和保护形式--确定选用框架式、装置式或限流式等。 (2)断路器的额定电压UN应等于或大于被保护线路的额定电压。 (3)断路器欠压脱扣器额定电压应等于被保护线路的额定电压。 (4)断路器的额定电流及过流脱扣器的额定电流应大于或等于被保护线路的计算电流。 (5)断路器的极限分断能力应大于线路的短路电流的有效值。 (6)配电线路中的上、下级艾驰商城断路器的保护特性应协调配合，下级的保护特性应位于上级保护特性的下方且不相交。 (7)断路器的长延时脱扣电流应小于导线允许的持续电流。
This selection principle: (1) according to the requirements of the protection circuit to determine the type and form of protection circuit breaker -- determine the selection of frame type, device type or current limiting type etc.. (2) the rated voltage UN of the circuit breaker should be equal to or greater than the rated voltage of the protected line. (3) the rated voltage of the undervoltage release of the circuit breaker should be equal to the rated voltage of the protected line. (4) the rated current of the circuit breaker and the rated current of the overcurrent release should be greater than or equal to the calculated current of the protected line. (5) the limit breaking capacity of the circuit breaker should be greater than the effective value of the maximum short circuit current of the circuit. (6) the protection characteristics of the circuit breaker at the upper and lower levels of the distribution line should be coordinated. The protection characteristics of the lower level should be located below the superior protection characteristics and disjoint. (7) the long delay tripping current of the circuit breaker should be less than the continuous current allowed by the wire.
