The Circulation Calculation and Analysis of the UHV-HGIS System with the Three-Dimensional Magnetic Field Model

Large mount of power loss can be caused by circulation in UHV shells and grounding system due to its high voltage level and large capacity. Taking a certain UHV HGIS switch station as example, the circulation value is obtained and analyzed through building a 3-D finite model of the switch station and analyzing its coupled electromagnetic field. Results of finite analysis and field-circuit coupling method are applied to calculation of circulation and temperature rise in grounding wires. Calculation results show that: the maximum of the shell circulation is about 3500A with the rated current 6300A on the bus. Adoption of bi-layer grounding network can limit the circulation value in the main grounding network to 20A, while 700A in the sub-grounding network. But this method proves no affection on the short wire current. How the vertical grounding electrode deep acts on the circulation value in grounding network is analyzed as well. The results can acts as reference for the UHV HGIS manufacturers.