Study On Fault Characteristic Parameter Monitoring Technology Of Underground Coal Mine Power Grid

The geological conditions and construction environment of underground coal mines are very harsh,coupled with the incorrect mechanical operation of the underground construction personnel or the occurrence of some mechanical external force collisions in the underground,which may directly cause various underground electrical equipment and The electrical insulation performance of the power supply control line is severely damaged,causing various common faults such as leakage,short circuit,overload,undervoltage,and degradation of insulation performance that may occur when the electrical power supply control line is interrupted.This article analyzes the common faults of coal mine underground power grids,and points out the current zero sequence current type,zero sequence power type,harmonic direction type leakage protection,short circuit type protection,grid overload,undervoltage,insulation performance degradation and other fault protection.Some problems exist.The coal mine power system model is established through the RTDS simulation platform,and the common short-circuit faults in the coal mine power system are simulated and analyzed,and the transient changes and steady-state parameters of single-phase short-circuit faults and three-phase short-circuit faults are analyzed.Regarding the problems of electromagnetic transformers that are widely used for current monitoring of underground power grids,it is proposed to use Rogowski coils for the improvement of current transformers,and its superiority is verified by simulation.Secondly,it introduces the power grid voltage detection system technology based on the optical fiber voltage sensor technology.In order to increase the stability of the optical fiber voltage sensor measurement and the reliability of the system,a set of optical path voltage loss compensation system design is proposed.In addition,it is also to reduce the measurement of the optical fiber voltage sensor.Error,a set of system noise reduction compensation system is designed.To solve the problems of fault protection such as leakage protection,short-circuit fault protection,grid overload,undervoltage,insulation delay,etc.,solutions were proposed.