Calculation and Analysis of Electromagnetic Field Radiated by Electronic Transformer under Disconnector Operation

The switching operation of disconnector in Gas Insulated Substation (GIS) will generate Very Fast Transient Overvoltage(VFTO), forming a transient space electromagnetic field, it causes electromagnetic interference to the electronic transformer connected with GIS and threatens its operation. This paper first studied the electromagnetic field interference of the very fast transient phenomena on the electronic transformer, and analyzed the coupling path of the electromagnetic field radiated by the electronic transformer. Then based on the transmission line theory, a three-dimensional electromagnetic simulation model of GIS connected electronic transformer with VFTO wave as excitation source is established, calculated and analyzed. The calculation results show that the internal radiated electromagnetic field is the most serious in the vertical position between the electronic transformer acquisition unit and the GIS conductive pole. The metal shell of the acquisition unit can act as an electromagnetic radiation shielding box and has a certain electromagnetic protection ability.