Research Of Single-phase Intermittent Arc Ground Failure In Coal Distribution Network

Single-phase intermittent arc ground fault is the type of failure with the highest frequency in coal mine power grid.The single-phase intermittent arc ground fault,because it is easy to cause repeated oscillations of capacitors and inductive parameters in the system,causes the problem of overvoltage endangering the whole network,which has a wide range of influence and high magnitude,which will cause the tripping to expand the power failure range and seriously threaten the safety of coal mine power supply.At the same time,the mine power cable is in the harsh environment of wet and corrosive for a long time,which is prone to damage and insulation deterioration,and the insulation level is reduced,which can easily lead to intermittent arc grounding failure in single phase,so it is of great significance to study the intermittent arc ground fault of coal mine power grid.This paper mainly focuses on the establishment of mathematical model and simulation model around single-phase arc fault,analyzes the overvoltage characteristics of coal mine power grid's single-phase intermittent arc ground overvoltage under different neutral point grounding methods,and studies the overvoltage suppression technology suitable for coal mine power grid.First of all,starting from the starting state of the physical process of arc,the state of arc current passing zero is decomposed by using the characteristics of AC arc.In order to avoid the limitation of linear arc resistance simulation,based on the black box model of nonlinear arc resistance,a transient simulation method of arc ground fault is proposed,which lays a foundation for analyzing arc light overvoltage characteristics.The simulation comparison and analysis of many kinds of classical models around the spectral characteristics of ground fault current and arc voltage provide theoretical basis and model basis for the subsequent study of arc ground fault simulation in coal mine power grid.A large number of simulation analysis shows that the arcing coil has a better prevention and control effect on the single-phase arc light ground overvoltage when the system single-phase ground capacitor current is large.