Study on electric field distribution of multi-layer dielectric under mixed voltage

Abstract

The combination of field and circuit analysis method is used. Taking the multilayer flat dielectric structure as an example, the electric field distribution law of multilayer dielectric under mixing and polarity reversal voltage is studied by using the electromagnetic field theory. Then, according to the actual situation, two typical multilayer dielectric structures are selected, equivalent circuit model is established, and multilayer dielectric equivalent circuit experiment is carried out. At the same time, the equivalent circuit is simulated and analyzed by using the circuit simulation to further analyze the distribution law of electric field under various voltages. On this basis, the finite element simulation is used to simulate the double-layer plate dielectric structure model, which verifies the applicability of the finite element simulation method in the calculation of AC/DC hybrid electric field. Finally, the structural model of ±800kV converter outlet bushing is established, and the AC, DC, AC and DC superposition and polarity reversal voltage are loaded respectively. The electric field distribution in each medium of the complex insulation structure is calculated and analyzed accordingly. The results show that the finite element simulation method is simple and effective, and it is feasible to study the electric field distribution law and insulation structure optimization of the complex insulation structure under AC/DC mixed voltage. This paper studies E-field distribution law of multi-layer media under AC/DC mixed voltage, which has practical reference significance for the external insulation design of converter bushing, wall bushing and converter valve, and is of the great value for the actual DC power transmission and transformation project.