湛江发电厂300 MW汽轮发电机定子绕组匝间保护误动分析及改进

由纵向零序电压原理构成的发电机定子绕组匝间保护因故障电压整定值较小，容易出现误动。结合湛江发电厂3号、4号发电机匝间保护误动情况，对发电机定子匝间保护的构成和特性等进行了分析，指出增加具有故障特征量的负序功率方向闭锁，改进电压互感器断线闭锁功能可以有效减少该匝间保护的误动。

Fault analysis and improvement on turn-to-turn protection for stator windings of 300 MW generators in Zhanjiang Power Plant

The turn~to~turn protection for generator stator windings based on the theory of longitudinal zero~sequence voltage is of inadequate faulty voltage settings and often causes undesired trip of units. This paper describes the misoperation of the turn~to~turn protection for the generators of Unit 3 and Unit 4 in Zhanjiang Power Plant, and analyzes the configuration and features of the protection. The methods of adding the interlock element based on negative~sequence directional power with fault characteristic quantity and improving the interlock element of voltage transformer disconnection are put forward to achieve the reliable operation of the relay.