基于三相对称电压注入法的配电网接地线检测技术

摘要

针对配电网线路发生“带地线合闸”这一恶性事故,提出了基于三相对称电压注入法的接地线检测技术,开发了基于数字信号处理器(DSP)的配电网线路临时接地线检测装置.将各频率电压注入信号下的采样电流值与阈值进行比较,利用比较结果综合确定配电网线路是否存在未拆除接地线.现场试验结果表明所提检测方法和开发装置可有效检测出未拆除的三相、两相及单相接地线,并可识别相间短路情况,从而方便检修人员快速确定并拆除临时挂接地线,实现安全合闸送电.%A technique based on the three-phase symmetrical voltage injection method for detecting the grounding wire of distribution network is proposed to prevent the serious accident of "closure with grounding wire",and a DSP-based device is developed to detect the temporarily-grounding wire of distribution network.The currents sampled under the injected voltages of different frequencies are compared with the thresholds to check if there is any grounding wire remained in the distribution network.The results of field test show that,the proposed method and the developed device could effectively detect any remained three-phase,two-phase or single-phase grounding wire,and identify the inter-phase short circuit fault,which simplifies the quick detection and removal of temporarily-grounding wire for the safe distribution network energizing.