基于复频率信号注入的直流接地极线路故障测距方法OA北大核心CSTPCD

In the context of equipping impedance monitoring systems for grounding electrode lines in DC transmission systems,the accurate calculation of the fault distance can be achieved by using high-frequency measured impedance characteristics.However,the analysis shows that the grounding electrode line of the DC system may produce the same high-frequency measured impedance under different fault conditions,which means that the measured impedance has not a one-to-one mapping relationship with the fault distance,and it is difficult to obtain the accurate fault distance from a single measured impedance.The paper analyzes the coincidence characteristics of high-frequency measured impedance with the variation of injected signals,proposes a fault location method based on composite-frequency signal injection,and provides a strategy for selecting composite-frequencies.The fault location method based on high-frequency measured impedance amplitude-phase characteristics is improved,and the fault location is calculated accurately.Finally,the feasibility and accuracy of the proposed fault location method are fully verified through simulation cases.