Research on the Detection Method of Core and Grounding Fault of Secondary Cable Based on the Principle of Cable Distribution Capacitor

Large power plants and substations generally use long control cables. Its step-wise capacitance cannot be ignored with a large cable length. Due to the existence of cable distribution capacitance, the control loop is seriously affected, which leads to the failure of the control loop, and even affects the normal operation of the equipment. Secondly, the distributed capacitance has a great impact on the grounding fault detection work, which may lead to the detection error and low sensitivity problems, and seriously cause the protection misoperation in the fault detection. In view of this, this study will analyze the core and grounding fault detection method from the secondary cable of the cable distribution capacitor principle, analyze its influence from the system architecture, the type of fault occurrence and the fault detection principle, and analyze the corresponding grounding fault detection method from the level of phase comparison and characteristic frequency.