LEAKAGE MONITORING METHOD AND SYSTEM FOR POWER CABLES OF SUBSTATIONS

Disclosed are a leakage monitoring method and system for power cables of substations. A residual current difference calculation method based on spatial vector transformation is proposed to omit the data preprocessing step for synchronizing signals at two ends under the premise of guaranteeing the calculation accuracy. Then, a leakage fault type determination mechanism for long power cables based on monitored residual currents of two ends and a monitored single-phase leakage current is constructed, and the leakages state and type of the cables can be diagnosed accurately based on three indicators, which are the difference between the residual currents, the single-phase leakage current, and the change rate of the radius of a spatial vector circle. The effectiveness and superiority of the method are verified by means of simulated and measured data, and the method of the invention is helpful to leakage fault analysis of relevant equipment of high-voltage substations.