基于导数法的电流互感器饱和新判据

A new derivative method to detect CT saturation point

电流差动保护中区外故障时电流互感器饱和而造成的电流传变误差,是引起电流差动保护误动的一个重要因素。文中对电流互感器饱和的原因作了简要分析,通过分析饱和电流波形,区分出由不同原因引起的电流导数波形的差别,并在其基础上提出了新的判别电流互感器饱和的方法———导数法。利用RTDS进行了详细的仿真试验,经过仿真试验证实,此方法可以迅速准确地判断出电流互感器进饱和点与出饱和点,从而防止因电流互感器饱和而引起的电流差动保护误动。

The current transmission error of CT saturation is one of the main factors of current differential protection maloperation. The principle of CT saturation is briefly introduced in this paper. On analyzing the saturation figures of CT secondary current, it gets the new CT saturation detection method——derivative method. In the end, RTDS is used to simulate the CT saturations and the simulation results prove that the new method can detect CT saturation quickly and exactly. It can prevent the maloperation of current differential protection in time.