Study On A High Voltage Test Equipment Of Impulse Oscillation And AC Superimposed Voltage

Dry-type air-core shunt reactor play a role in improving the ability of transmission power in long-distance electric transmission line,perfecting voltage distribution along the line and reducing system over-voltage,so it is occupied important position in the power system.But in recent years,there have been a lot of fire accident about dry-type air-core shunt reactor.The relevant investigation has shown that switching over-voltage is one of the main reasons of the burnout accident.This is a kind of over-voltage waveform that impulse oscillation superimposed AC voltage peak,in order to study the destructive effect of this kind of over-voltage,firstly need to develop a set of high voltage test equipment that it can produce this particular over-voltage waveform.This paper analysis chopping current over-voltage and reigniting overvoltage when the circuit breaker switch dry-type air-core shunt reactor by the way of theoretical analysis and simulation verification,specific voltage waveform is given;in order to simulate the actual reactor turn-to-turn insulation,the turn-to-turn insulation sample model is made.Breakdown voltage levels of turn-to-turn insulation sample are determined under ac voltage and impulse oscillation voltage.Based on the theory of circuit,this paper come up with a kind of superimposed circuit in parallel and a kind of superimposed circuit in series,through analysis circuit principle by mathematical methods and simulation verification,circuit parameters are determined.In order to make high frequency impulse oscillation voltage overlays AC voltage in the peak and sphere gap discharge two times a second,this paper developed a set of control circuit of discharging sphere gap,and use Altium Designer simulation software to wire and print the circuit board,and its feasibility is verified by experiment.On the basis of,design the associated high-voltage components and the whole control system,established a set of high voltage test equipment,using oscilloscope to observeoutput voltage waveform.The research results show that chopping current over-voltage is a kind of impulse oscillation waveform,reigniting over-voltage is a kind of over-voltage waveform that impulse oscillation superimposed AC voltage peak;Breakdown voltages levels of dry-type air-core shunt reactor turn-to-turn insulation sample are 30 k V under ac voltage and impulse oscillation voltage;the voltage waveform generated by superimposed circuit in series is closer to switching over-voltage,ac voltage and impulse oscillation is easier to adjust,experiment confirmed that impulse oscillation voltage superimposed ac voltage peak nearby,both power frequency ac voltage and impulse oscillation voltage can be continuously adjustable in 0~30k V,sphere gap discharge twice a second.This paper confirms the method producing high frequency impulse oscillation voltage superimposed on power frequency AC voltage is feasible;this high voltage test equipment lays the foundation for subsequent dry-type air-core shunt reactor turn-to-turn insulation breakdown experimental study.