Application Of Power Electronics Disturbance Technology In Resonant Grounding System

Small current grounding mode is the main operation mode of medium and low voltage distribution network system at present,Ungrounded neutral point and harmonic grounding are two main grounding modes for low current grounding.The resonant grounding system can compensate the capacitive current of the power grid,and can continue to operate for 1 to 2 hours in case of grounding fault,so as to improve the reliability of power supply.But the tuning of arc suppression coil needs to be based on the measurement of capacitive current in power grid.Moreover,with the improvement of the modernization level of the country,the structure of the power grid is becoming more and more complex,and the asymmetry of the system is becoming more and more obvious.At present,the measurement of ground capacitive current is basically based on symmetrical system.For the asymmetric system,the effect of adjusting the arc suppression coil to compensate the capacitive current obtained from the symmetric system is not so ideal.In addition,because of the existence of arc suppression coil,the phenomenon of single-phase grounding fault is not so obvious.For resonant grounding system,the identification of fault line is also a difficult problem to be solved.Therefore,it is necessary to study the measurement of ground parameters and fault line identification of resonant grounding system in order to improve the safe operation and power supply reliability of resonant grounding system.Firstly,the research status of capacitance current,arc suppression coil and fault line selection of small current grounding system is described.Aiming at the normal operation state of resonance grounding system and the principle of fault operation state,the detailed analysis is made,and a more intuitive simulation is built to show the change of voltage and current when fault occurs.Then,a method of fault line identification of resonance grounding system is given.Law.Next,aiming at the phenomenon of asymmetric system,a method of measuring the relative ground parameters of resonant grounding system is presented.For the identification of fault line and the measurement of ground parameters,the corresponding models are built by using the simulation tools of MATLAB/Simulink,and the proposed theory is simulated and analyzed to verify its correctness.In this paper,the method of power electronic disturbance is used to study the tuning of resonant grounding system and the identification of fault line.The validity of this new method in the two aspects of resonant grounding system is verified.