用于串联电容器组快速保护的可控多级火花间隙

Controllable Multi-stage Spark Gap Used in Fast Protection for Series Capacitor Bank

为提高串联电容器组快速保护装置的可靠性,开发了一种新型的可控火花间隙—Tesla变压器驱动的与频率相关的多级火花间隙。与现有3电极间隙依靠运行电压触发的工作原理不同,这种新型间隙的可靠快速动作完全不受它承受的运行电压的影响。利用多级间隙与Tesla变压器试验样机对新型可控间隙的动作过程、可靠动作概率和动作时间等动作特性进行了试验研究。研究结果表明:通过合理设置参数,新型可控间隙的工频耐受电压可以达到串联电容器组工作电压的10倍以上,确保不会误动作,而选取动作阈值电压足够高就可以保证保护装置具有极高的动作概率,消除拒动,具有极高的可靠性;新型保护系统动作时间≤20μs,具有很高的动作速度。

In order to improve the reliability of by-pass protective device for series capacitor bank, we developed a novel controllable spark gap, namely, the frequency-depending multi-stage spark gap driven by Tesla coil. Unlike the existing three-electrode gap that triggers according to operating voltage, the proposed novel gap is independent of the voltage applied on it while working reliably and fast. Through experiments on a prototype, we measured the proposed gap＇s action characteristics, including its action process, successful action rate, and action duration. The results show that, with reasonable settings, the spark gap has a power frequency withstand voltage of 10 times higher than the operating voltage of series capacitor bank, which prevents any malfunction. Regarding to a protection system using the proposed spark gap, if its action threshold voltage is high enough, its actuation probability will be extremely high that reduces actuation failure and greatly improves the system＇s reliability. Generally, the actuation time of the protection system will not exceed 20 μs, which means a fairly high actuation speed.