提高发电机定子接地保护动作可靠性的措施

Measures on improving the ground protection action reliability of generator stator

某电厂210 MW汽轮发电机组带191 MW负荷运行,发电机定子接地三次谐波保护动作发信,基波零序电压变化较大。通过对采样数据的分析,否定了定子绕组单相接地的可能,考虑到基波零序电压整定较灵敏,退出了该保护的功能压板,避免了保护误动切机事故。并且从TV一次断线闭锁保护的缺点、保护原理的确定、变比修正系数的计算、TV一次绕组接地等方面,提出了提高发电机定子接地保护动作可靠性的措施。

Stator 8Tound protection based on the third harmonic transimitted and zem-sequenca volta$e changed 8rcatly when 210 MW 8ns-generator was working with 191 MW load. The analysis of sampled data indicated sinsle-phase ground is impossible. Bein8 considered of fundamental zero-sequonce voltage sensitive setting, the faction plate of the protection exited to avoid cutting machine accident of the protection malfunction. Measures of impmvin8 the reliability of 8on^r stator 8round protection action was put forward based on the defect of TV break blocking, the detenninatlon of protection principle, calculation of variable fixed coefllcient and TV grounding of the primary winding.