光伏系统直流母线电弧故障的固有频率法测距

提出一种基于固有频率法的直流母线电弧故障测距方法。在电弧故障发生后,记录输电线首端的一段暂态电压信息;对于串联电弧故障,取断路器动作后的数据;对于并联电弧故障,则取断路器动作前的数据。提取固有频率主成分后,代入公式d-v/(2f)均可实现对串联和并联电弧故障点的测距。与传统行波法测距相比,具有计算简单、测距精度高以及成本低的优点。通过电路模型仿真与低压直流输电平台实验,证明了方法的可靠性与实用性。试验结果表明,该方法的测距误差在6%以内。

LOCATING ARC FAULT OF DC BUS IN PHOTOVOLTAIC SYSTEM BY NATURAL FREQUENCY METHOD

This paper presented a DC arc fault location method of the cable by natural frequency. Firstly, a transient voltage information is recorded at the first end of the transmission line after an arc fault occurs. For series arc fault, by extracting the data after circuit breaker action. For parallel arc fault, by extracting the data before circuit breaker action. Then the principal component of natural frequency can be chosen. Finally, a specific formula d-v/(2f) is used to calculate the distance of fault points whatever series or parallel arcs distance. Compared with the traditional traveling wave method, it has the advantages of simple calculation, high accuracy and low cost. The reliability and practicability of the method are proved by circuit model simulation and experiment test with a low voltage DC transmission platform. The test results show that the distance measuring error is less than 6%.