COMSOL Multiphysics-Based Multi-Physics Field Virtual Simulation of Electronic Transformer

Electronic transformers are often used in conju nction with gas-insulated switchgear in power systems in har sh conditions. The current flowing through the high-voltage conductors of electronic transformers causes the device to he at up, which affects the reliable operation of the device. In this paper, the multi-physical field coupling simulation model of the electronic transformer is established based on COMS OL Multiphysics, taking into account the electromagnetic hea t and solid and fluid heat transfer characteristics, and the l aminar flow analysis of sulphur hexafluoride installed in the electronic transformer section is carried out. The higher tem perature at the top inside the device, the faster velocity top flow rate of SF6 gas, the uniform distribution of the y-comp onent of the velocity field inside the device, the internal pre ssure contour and the magnetic flux density are obtained fro m the analysis to evaluate the compatibility of the electronic transformer with the gas-insulated switch combination, and to verify the results by comparing them with the theoretical analyses. The multi-physical field coupling simulation model proposed in this study has good accuracy and lays a theoret ical foundation for the experimental tests related to electroni c mutual inductors as well as the optimal design.

I. Introducton

Electronic transformers, as an important electrical device for measurement in power systems, are usually integrated with gas-insulated switches and used together, which have high requirements for their multi-physical field compatibility due to being in a high load operation state all year round and experiencing various extreme environments. Among them, too high a temperature rise will reduce the insulation level of the gas-insulated switchgear device, cause partial discharges or even lead to insulation breakdown, which adversely affects the safe and stable operation of the gas-insulated switchgear device, and is one of the main failures. In order to ensure the stability of the electronic transformer when it is connected to the network, it is necessary to carry out multi-physical field testing before practical application.