基于检测电流变化量的母线快速CT断线判断方案

Bus rapid CT break detection based on current variation

为了准确快速判断出电流互感器(CT)断线,提高母线保护的可靠性,分析了CT断线及母线故障时的电流波形,提出了一种基于电流变化量特点判别CT断线的方案。该方案主要根据CT断线的特点,将傅里叶算法与采样点算法相结合,既保持了傅里叶算法的优点,又增加了采样点算法的快速性,能在很短的时间内判出CT断线。此方案可保证母线保护在CT断线情况下不误动,在母线故障时不误判CT断线。

In order to detect the current transformer( CT) disconnection quickly and accurately and at the smae time to improve the reliability of the protection bus,the wave about the CT break and bus failure were analyzed. A project was put forward based on the characteristics of the current variation. This scheme combines the Fourier algorithm with sampling point algorithm,which not only maintains the advantage of the Fourier algorithm,but also increase the velocity of the sampling point algorithm. The CT disconnection can be judged in a short time. The scheme can ensure that the bus can't be falsely tripped under the CT disconnection and line break can't be misjudged at the bus failure.