应用相控合闸技术抑制并联补偿线路断路器直流偏置问题的研究

笔者对带有并联电抗器的线路,合空线操作时流过断路器电流的直流偏置问题进行了分析。在对直流偏置产生的原理、影响因素及可能引发故障风险的工况进行分析的基础上,对控制合闸相位、降低补偿度以及加装合闸电阻等抑制直流偏置的措施进行了比较。并进一步对应用合闸相位控制技术抑制直流偏置的相关技术进行了研究,包括控制策略、反馈参数以及对操作过电压的影响等方面。在此基础上针对典型线路对相控合闸技术的应用效果进行了实测,证明了限制效果的有效性,并对其适用范围进行了分析。

Application of Phase Control Technology in the Prevention of DC Offset Risk of Circuit Breaker of EHV Transmission Line with Parallel Reactance

In this paper the DC omponent in current of circuit breaker during transmission line energizing is analyzed.The impact of closing phase,compensation degree and closing resistors of circuit breaker on the amplitude of DC component are discussed.And measures which could be taken to prevent the failure risks of circuit breakers caused by DC offset are also studied.Phase control technology is chosen as the most feasible measure on the base of comparison of the applicability of all the measures,which include phase control breaker closing,reducing compensation degree and addtion of closing resistors.The application of phase control technolgy on the prevention of DC offset is studied.The phase control strategy of breaker closing,and the monitor variable for adaptive feedback regulation are disscussed.The impact of application of phase control on operationg overvoltage is also analyzed by simulation with PSCAD/EMTDC.The effectiveness of phase control breaker closeing on DC offset prevention is valided by field test on a typical transmission line.The impact of mechanical dispersion and pre-breakdown between contacts of circuit breakers are discussed on base of the test results,and the applicability of phase control is also analyzed.