Hence, occasional line failures occur as a result of these causes.Failures caused by wind or sleet are usually of such nature that repairs must be made before the line may be reenergize .

• 要对电流、电压和其它量的测量仪器进行监控，必须能够辨别出产生故障的设备，使断路器开始起作用并将有故障的设备排除在供电服务之外，而让运行系统中其它所有设备继续运行。