Structure Design And Simulation Analysis Of Compact 500 KV Impulse Voltage Generator

In recent years,the construction of UHV AC and DC projects has been rapid,and it is impossible to fully discover the defects of core electrical equipment such as GIS only by relying on on-site power frequency AC withstand voltage and partial discharge tests,which is easy to leave safety hazards.Therefore,before the electrical equipment is put into operation,it is necessary to carry out on-site lightning shock and operational impact withstand voltage tests to comprehensively test the insulation performance of the equipment.However,the traditional impact test device is large in size,the difficulty and cost of transportation are high,and it is not conducive to on-site installation,resulting in some equipment not yet carrying out on-site impact pressure test.It is therefore important to design a compact,movable impulse voltage generator suitable for on-site shock withstand voltage testing of electrical equipment.In this paper,the theoretical analysis and corresponding parameter calculation of the compact "back-to-back" Marx circuit boost structure were first carried out,and the boost circuit structure of the subsequent design of the impulse voltage generator was clarified.Based on its circuit structure,solid-state MOSFET switches had preliminarily demonstrated that this structure could be used to output pulse waves with pulse widths in the μs range and negative polarity.Secondly,the overall circuit of the compact 500 kV impulse voltage generator device required by the project was designed,the main circuit adopted the abovementioned compact Marx circuit after verification,and output two standard waveforms of lightning shock voltage and operating shock voltage by connecting two sets of modulation resistors with different resistance values,and used this as a reference to calculate the parameters of each component in the device and PSpice circuit simulation,and determined the core parameters of the circuit as:AC source charging voltage 57 kV,energy storage capacitors a total of 11,The capacity was 2 μF;when the wavefront resistance value was 20 Ω and the end resistance value was 350 Ω,the wavefront time could be output 1.24 μs,the half peak time was 50.12 μs,and the voltage amplitude was 560.26 kV;when the wavefront resistance value was 8 kΩ and the tail resistance value was 70 kΩ,the wavefront time could be output 249.32 μs,the half peak time was 2430.23 μs,and the voltage amplitude was 555.12 kV.Finally,under the premise of fully considering compactness,according to the above calculation and circuit simulation results,the corresponding actual components were selected,and a compact 500 kV impulse voltage generator 1:1 scale threedimensional model was constructed according to the size of each component,and the COMSOL electrostatic field simulation analysis was carried out.When the device outputs two standard waveforms normally,the switch adopted trigger breakdown,the clearance of the first to fifth stages was 20.60 mm,and after a variety of electric field optimization measured,the volume of the outer insulating cylinder of the entire unit was 0.55 m3,and the maximum field strength of the normal operation process of the device is 2.29×104 kV/m,which is less than the breakdown field strength of the peripheral domain(transformer oil).The results showed that the device achieves compactness while meeting the insulation requirements without partial breakdown,according to the optimized size,the structure of the main model of the device and the overall construction method were designed.In summary,this paper calculated and simulated the parameters of each component in the device by calculating and simulating the parameters of the compact 500 kV impulse voltage generator device,and simulated two standard waveforms;according to the determined component parameters,the three-dimensional model of the device was constructed with reference to the actual size of the component and the corresponding electric field simulation optimization was carried out.The work done in this paper provided a reference for the subsequent construction of the structure of the compact 500 kV impulse voltage generator and the construction of the test circuit,and also accumulated experience for the design of the 2.4 MV compact impulse voltage generator in the project.