摘要
通过理论分析和大量6 kV模拟试验验证,研究了电弧接地故障时暂态零序测量电流的特征,以及故障线路与非故障线路暂态零序测量电流之间的关系:①电弧接地时,零序电压和各馈线零序电流中都有高频衰减的暂态分量。暂态分量的频率主要与变压器漏抗、电网对地电容和相间电容有关。暂态分量的特征基本不受中性点接地方式的影响。②故障线路与非故障线路的零序暂态电流在频率、衰减速度等特性上相同。非故障线路零序暂态电流的大小与本线路对地电容的大小呈正比,而故障线路零序暂态电流等于所有非故障线路零序暂态电流之和,但方向相反;零序暂态电流的衰减速度随电弧电阻的增大而加快。③单相接地故障发生在相电压最大值附近时,暂态零序电流最大,发生在相电压过零点附近时最小。在此基础上,提出一种新的、能在单片机上实现并满足在线实时选线计算需要的单相接地故障暂态电流选线算法。经实验数据证明,该算法对电弧接地故障是有效的。
With the theoretical analysis and lot 6 kV simulation experiment certification conducted, the paper studied the features of the transient zero-sequence current at an arc ground fault and the relationship of the transient zero-sequence current between the fault line and non-fauh line. ① At an are grounding, there was a transient component of high frequency attenuation in the zero-sequence voltage and zero-sequence current in each feeder line. The frequency of the transient component was mainly related to the leakage impedance of transformer, the grounding capacitances of the power network and the capacitances between the phases. The features of the transient component basically was not influenced by the grounding pattern at the neutral point. ② The zero-sequence transient current of the fault line and non-fault line would be the same in frequency, attenuation speed and other features. The high or low of the zero-sequence transient current in the non-fault line would be a direct proportion to the high or low of the grounding capacitance of the line. The zero-sequence transient current of the fault line would be the total of the zero-sequence transient current of all non fault line. The attenuation speed of the zero-sequence transient current would be increased with the increasing of the arc resistance. ③ When the single phase grounding fault occurred near the max value of the phase voltage, the transient zero-sequence current would be maximum. When the single phase grounding fault occurred near zero point of the phase voltage, the transient zero-sequence current would be minimum. Based on above, the paper provided a new transient current line calculation method for the single phase ground fault base on the single-chip micro computer to meet the on line and in time calculation. The experiment date showed that the above calculation method would be effective to the arc grounding fault.
出处
《煤炭科学技术》
CAS
北大核心
2008年第8期65-69,112,共6页
Coal Science and Technology
关键词
配电网
暂态零序电流
小电流接地选线
单相接地故障
power distribution network
transient zero-sequence current
small current earth line
single phase ground fault
