Analysis of Resonant Grounding Mode for Urban Distribution Network Considering Capacity Current Variation

With the fast encouragement of urban expansion and construction, the need for electricity is rising quickly among all levels of power users. At the same time, people's demand for environmental aesthetics has increased, which has led to the widespread use of power cables. The ground capacitance per unit length of cables has significantly grown when compared to traditional overhead lines, leading to an intensified growth of capacity current in cable-based urban distribution network, which poses a huge challenge to the traditional resonant grounding mode. A model of a 10kV urban distribution network with capacity current variation is created based on the typical outgoing line structure of substations. The effects of capacity current and transition resistance on the fault point current and the zero-sequence current of the fault line are investigated, and the fault point current is further reduced by enhancing the accuracy of the arc suppression coil. Furthermore, the deviation of the fault point current caused by the arc suppression coil's adjustment mistake has also been thoroughly taken into account. The analysis of the compensation effect and pros and cons of retaining the resonant grounding mode in the urban distribution network with capacity current variation from multiple angles offers a theoretical foundation for the distribution network's neutral grounding mode selection.