针对10 k V及以下电压等级配电网线路检修或改造过程中临时挂接地线检测问题,研究一种变频信号注入检测方法,并开发基于DSP2812的防带地线合闸检测装置,装置生成变频电压检测信号,并不断注入到检测回路中,回路由装置、线路、接地线和大地等构成,检测回路的三相电压、电流信号不断被采样,经调理后输入至CPU进行综合判断分析,从而对线路是否存在三相接地线、两相接地线、单相接地线和无接地线情况进行有效检测,并对线路相间短路情况进行识别。装置基于模块化设计,采用高速数据处理芯片,利用FFT算法分别求解基波和谐波成分,不仅可有效判断出有用信号,还可以判断线路中感应信号的强弱,现场试验表明其在技术上可有效避免"带地线合闸"这一恶性事故,有一定的参考价值。
Aimed at problems of temporary hanged grounding wire detection during lines maintenance or rebuilding work of distribution network in 10 k V and under the voltage grade,a detection method based on variable frequency injection principle was studied,and a detector device for anti-closing with grounding wire was developed based on DSP2812,and the variable voltage signal was produced and injected into the detection loop circuit,which was composed of detector,distribution line,grounding wire and the earth,etc. Three-phase voltage and current signals were sampled,and after conditioning,were transmitted into CPU for comprehensive analysis,which could detect the wires in three-phase,two-phase and single-phase grounding situations,as well as no grounding and inter-phase short connection situations. The detector was based on modular design with high speed data processing chip,and in which the FFT algorithm was used to resolve the fundamental wave and harmonic,could availably judge the useful signals,and the intensity of inductive signal existed in wires. It is proved from the field test that the vicious accident of " closing with grounding wire" can be avoided in usage of the designed detector and which has a certain reference value.