Rapid Identification Method for Potential Risks of Single-phase Reclosing Failure

To ensure safe power supply and stable operation of the power grid, single-phase reclosing technology is widely used in domestic and foreign power systems. Except for some power plants, there is no special control strategy or requirement for the single-phase reclosing timing. Multiple circuit breaker failure accidents caused by single-phase reclosing under permanent faults have occurred in the domestic power system, which caused the expandation of accidents and seriously affected the safe and stable operation of the power grid. To avoid the occurrence of such accidents, this article conducts research on a rapid identification method for the potential risk of single-phase reclosing failure. Starting from the mechanism of single-phase reclosing failure, through electro-magnetic transient simulation and actual fault recording analysis, revealing decisive influencing factors of single-phase reclosing failure. Derive the calculation formula for short-circuit current after single-phase reclosing, and propose a risk assessment index, which is risk level of single-phase reclosing failure RANK, for single-phase reclosing failure under the most serious operating conditions. This index describes the probability of circuit breaker failure caused by single-phase reclosing. Based on short-circuit current calculation program in DSP (Digital Simulating Platform), one-click-identification for single-phase reclosing failure risk module is developed. The calculation accuracy is verified by comparing with the results of electro-mechanical and electro-magnetic transient simulation. The module conducts calculation and analysis based on the real operating data of the power grid, providing guiding suggestions for relevant departments in power grid company, effectively supporting the key work of safety risk prevention and control in China’s power grid.