Affiliations: [a] Key Laboratory of High Voltage Field Test Technique of SGCC, State Grid Hubei Electric Power Research Institute, SGCC, Wuhan, China | [b] Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA | [c] State Grid Hubei Electric Power Company, SGCC, Wuhan, China | [d] State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, China | [e] State Grid Henan Economic Research Institute, SGCC, Henan, China
Correspondence:
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Corresponding author: Bo Zhang, Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. E-mail: zhangb18@rpi.edu, bozhang321@gmail.com
Abstract: An actual occurred ground-fault accident of 500 kV transformers in HVDC converter station is presented. A 2D transient electromagnetic-thermal-mechanical finite-element coupling model of 500 kV transformer is developed to analyze the transient process of failure, with consideration of the resistance-temperature relationship and plasticity displacement in the windings’ thermal and mechanical characters. To verify the proposed finite-element model, the model is calibrated by pre-fault field test of the transformer in steady state, which shows good agreement with measurement. The short-circuit current adopted in simulation is based on actual on-site measurement of the ground-fault accident. By using the proposed model, simulation results reflect the transient process and explain the post-fault inspected damage well in term of over burn regions in thermal analysis and deformation tendency in mechanical analysis when compared with field post-fault inspection photos.
Keywords: Electromagnetic analysis, finite-element, transformer, ground-fault accident and DC grid
