例一：某35kV无人值班变电所，故障发生前为两台6300kVA主变并列运行。2001年6月21日上午，监控中心运行人员远控将1#主变有载分接开关由4档调至5档时，发现档位指示停留于4档，不能改变。即指示变电所值班人员到现场查看，发现有载分接开关本体由呼吸器及顶盖部渗油，并有逐步 Example 1: A 35kV unattended substation, before the failure occurred for the two 6300kVA main transformer parallel operation. On the morning of June 21, 2001, when the remote control personnel of the monitoring center shifted the on-load tap-changer of No. 1 main transformer from No. 4 to No. 5, it was found that the indication of stall remained at No. 4 and could not be changed. That is to instruct the substation on duty to inspect the site and found the on-load tap-changer body from the respirator and the roof Department of oil leakage, and step by step