基于零序电流比幅法的故障选线法

Method of Fault Line Selection Based on Zero-Sequence Current Comparison of Amplitude

针对10 kV配电网小电流接地故障时单台智能控制器零序电流测量误差比较大、选线难的问题,基于零序电流比幅法设计了一种适合在柱上开关智能控制器实现的零序电流选线方法.该系统采用专用的电能计量模块和单片机来测量并计算线路的零序电压、零序电流和相电流,当零序电压超过设定值后,根据相电流的大小计算零序电流的随机误差,用零序电流实测值和随机误差求出偏移量,并通过GSM模块通信的方法对各条线路的零序电流偏移值进行比较排序,为单相接地故障提供选线依据.通过仿真试验验证了算法选线准确.该系统实用、安装简单、现场使用方便可靠.

Zero sequence current＇s measurement error of small current grounding fault for single intelligent controller in 10 kV distribution network was relatively large and line selection was hard. Based on zero-se- quence current comparison of the amplitude, the method of zero sequence current line selection for intelligent controller was designed. Zero sequence voltage, zero sequence current and phase current were measured and calculated by the special electric energy metering module and MCU. When the zero sequence voltage exceeded preset value, random error of zero sequence current was calculated according to the value of phase current, the offset was calculated by the random error and measured value, and the zero-sequence current offset value of each line was compared and sorted through the method of GSM communication module. Basis of line selection for single phase to ground fault was provided. The algorithm is verified by the use of simulation results and line selection is accurate. The system is utility, easy to install and convenient and reliable to use in the site.