一种断路器开断燃弧时间检测新方法

Method to detect arcing time of circuit breaker

准确测量断路器燃弧时间的关键是确定电弧的起弧时刻。根据断路器开断时开断电弧的模型,详细分析了断路器开断前后电流的变化过程和开断相角等因素对燃弧时间的影响,提出了一种基于暂态电流的燃弧时间检测方法。通过对线路发生故障后的部分故障线路的三相电流录波数据滤波后进行拟合,预测之后的电流变化,并与实际电流数据比较,求得电流畸变量。当畸变量大于设定阈值时,即可认为该时间点为断路器的触头始分点;断路器首开相的触头始分点即起弧时刻。开断完成的时间点即熄弧点为相电流小于设定阈值的时间点,末开相的熄弧点为熄弧时刻。起弧时刻与熄弧时刻之间的时间差为断路器的燃弧时间。利用电磁暂态分析程序EMTP仿真证明了该方法的可行性和较高的可靠性。

The detection of circuit breaker arc starting time is the key of precise arcing time measurement. Based on the switching arc model,the current change during circuit breaker switching process and the influence of switching phase angle on arcing time are analyzed. A method to detect arcing time based on transient currents is presented. The recorded data of three phase currents after line fault are filtered and fitted to forecast the current change,which are compared with the actual data. The time when the difference is just higher than the threshold is taken as the eontactor opening time and the first one as the arc starting time, while the time when the line current is just lower than the given threshold current is taken as the contactor complete open time and the last one as the arc extinction time. The interval between the arc starting time and extinction time is the circuit breaker arcing time. Simulation with EMTP verifies its feasibility and reliability.