Research On Single-phase Grounding Fault Compensation Method Of 10kV System Based On Expansion Arc Suppression Coil

With the development of science and technology,the research of neutral point grounding via arc suppression coil has entered a rapid development period.Breakthrough has been made in single-phase ground fault current measurement and fault line selection,but the arcsuppression coil structure and control methods have not made great progress in recent years.So far,the use of fully compensated arc-suppression coil to compensate single-phase ground fault of the system still has the defects of high cost and imperfect technology.Nowadays,the use of arc-suppression coil is still dominated by manual turning control.However,with the increasing of the system fault capacitance current,the traditional manual turn control arc suppression coil has gradually been unable to meet the needs of the system.In this paper,in order to solve the traditional adjustable turn type arc suppression coil capacity constrained and compensate the disadvantage of slow speed,with the arc suppression coil itself as a starting point,switch capacitance and adjustable turn type two kinds of traditional coil advantage analysis,expansion arc suppression coil is put forward,and based on the expanded to 10 k V single-phase grounding system arc suppression coil compensation method is studied,when finish measurement and compensation of capacitive current and fault judgment.Firstly,the three concepts of the neutral point ungrounded,the neutral point grounded by resistance and the neutral point grounded by arc suppression coil are elaborated in detail.The advantages and disadvantages of the three kinds of grounding methods are compared and analyzed,and the superiority of the neutral point grounded by arc suppression coil is verified by MATLAB/Simulink simulation data.Then,the working principle and construction mode of the conventional and capacitive arc-suppression coil are discussed emphatically.On this basis,the concept and construction mode of the capacitive arc-suppression coil are proposed.The coil adopts parallel inductance structure instead of the traditional series method to realize the expansion of the device.Based on the traditional equal-difference and equal-ratio structure of the current compensation for the arc suppression coil,the current equal-difference structure and the high-precision multi-position structure are adopted for the capacitive arc suppression coil.According to the two gear construction methods,two compensation methods are proposed to compare the current-per-gear adjustment control and the cross-gear adjustment precise control,so as to realize the 4-gear and 15-gear expansion arc suppression coil of the 4-component inductance combination.Moreover,MATLAB/Simulink simulation data are used to verify the compensation effect of the two design schemes on the fault capacitance current.Finally,a comparative analysis is made on the measurement of fault capacitance current and fault line selection after the single-phase grounding fault of the system.The tuning method is adopted to accurately measure the capacitance current and realize fault line selection by means of parallel resistance.The optimal value of the parallel resistance is determined through the supervision mathematical model and MATLAB/Simulink simulation calculation.The current measurement,compensation and fault line selection of the 10kV system based on the single-phase ground fault of the spread capacity arc suppression coil are completed.The results show that the spread capacity arc suppression coil has faster compensation speed and higher compensation capacity than the traditional turn control arc suppression coil,which is more conducive to the safe and reliable operation of the system.