预防电缆沟起火的小电流接地系统单相接地故障处理

To avoid a cable trench fire caused by a single-phase grounding fault in a small current grounding system, this paper uses a fire dynamic simulation analysis method to define the time and space threshold of cable trench ignition caused by the arc fault. Comprehensive control measures to prevent a cable trench fire are described. We discuss how the method is implemented and the test data of the phase-controlled pre-adjustment arc suppression coil. The advantages of both the phase-controlled arc suppression coil and the pre-adjustment arc suppression coil are described. This paper also describes the processing method for the cross-country earth fault, including a continuous detection process of transients and supplementary processing of the steady-state. The setting basis of single-phase grounding protection trip delay and the treatment method for an intermittent grounding fault are given. We discuss a centralized intelligent fault-tolerant single-phase grounding fault handling method and distributed intelligent single-phase grounding fault handling method based on closing and quick breaking respectively for urban and suburban distribution lines. The effectiveness of the technical measures is demonstrated by the overall application of the distribution network in the power supply area of 172 110 kV substations in Shaanxi province.