半山发厂给水泵电气保护调试的问题及处理

半山发电厂给水泵电气保护,由于电动机启动电流比较大,电流互感器比值误差大于10 % ,励磁电流急剧增加,从而在电动机启动时继电保护中产生过大的不平衡电流而引起差动保护误动作。因此,差动保护应尽量选用型号和励磁特性相同、且变比合适的电流互感器,以尽量减少因电流互感器引起的不平衡电流对继电保护装置的影响,防止差动保护误动作。

Problems and Remedy in Test and Adjustment of Electrical Protection for Feedwater Pumps in Banshan Power Plant

For the electrical protection of feed-water-water pumps in Banshan Power Plant,due to relatively large start-up current of the motor,the ratio error of the current transformer is greater than 10%,the exciting current is increased suddenly,as a result,the excessive unbalancing current produced in the relay protection causes the malfunction of differential protection.So the differential protection should select the current transformer with the model same as the exciting character and proper transformation ration to reduce the effect of the unbalancing current caused by the CT on the relay protection and prevent the differential protection from malfunction.