阻容过电压吸收装置在地铁供电系统的应用分析

Analysis of Application of Resistance-capacitance Overvoltage Absorption Device in SubwayPower Supply System

真空断路器分断空载变压器时产生的操作过电压在地铁供电系统中多次出现,既有常规设计中的过电压防护方案已不能满足现场供电运营要求。本文对真空断路器分断时产生的过电压进行理论分析,得出该过电压的特征;简要论述避雷器及阻容过电压吸收装置的工作机理,研究了变压器35 kV侧设置避雷器或阻容过电压吸收装置以抑制操作过电压的效果。仿真表明,避雷器无法有效抑制过电压陡度及频率;阻容过电压吸收装置可以改变振荡回路总电容,有效降低过电压的陡度和频率,抑制断路器的截流过电压和重燃过电压。为方便选型,给出了阻容过电压吸收装置主要元器件参数。

There operating over-voltage occurred frequently in the subway power supply system generated by the vacuum circuit breaker when it is tripping the no-load transformer,and the over-voltage protection schemes in the conventional design are no longer meeting the requirements of the power supply and operation at site.The paper analyzes theoretically the over-voltage produced by the vacuum circuit breaker when it is tripping and obtains the characteristics of the over-voltage;illustrates briefly the working mechanism of the lightning arrestor and resistance-capacitance over-voltage absorption device,studies the effectiveness on suppression the operating over-voltage by setting of lightning arrestor or resistance-capacitance absorption device at 35 kV side of the transformer.The simulation shows that the lightning arrestor is unable to absorb the steepness and frequency of the over-voltage;resistance-capacitance absorption device is able to change the total capacitance of the oscillation circuit,lower effectively the steepness and frequency of the over-voltage,suppress the intersected over-voltage and re-strike over-voltage generated by the circuit breaker.The main component parameters of the resistance-capacitance absorption device have been presented in order for easy type selection.