大型发电机组过负荷保护反时限特性分析与改进

Study on Over Load Protection Inverse Time Lag Property of Large Scale Generation Unit and Improvements

针对大型发电机组保护的反时限特性与机组实际发热过程常难以准确拟合的问题,通过定子过负荷保护反时限动作方程的推导,分析对数反时限动作方程与通用反时限动作方程的区别和联系,得出对数反时限特性更接近机组实际过负荷发热过程的结论。根据大型发电机组运行工况复杂的特点,对定子绕组过负荷保护的反时限动作判据提出了改进建议,解决了热积累对机组安全的影响。

Aiming at difficulties in correct matching of inverse time lag property of large scale generation unit and practical heating of the unit, this paper analyzes differences and connection of logarithmic inverse time movement equation and com- mon inverse time movement equation by deduction of inverse time movement equation of stator over load protection and draws a conclusion that logarithmic inverse time property is more close to practical over load heating process of the unit. Ac- cording to complicated working condition of large scale generation unit, it proposes improvement suggestions for inverse time movement criterion of stator winding over load protection which solves problem of affection on safety of the unit by heat summation.