Grounding Current Mechanism of Converter Transformer Core and Clamp

This paper analyzes the mechanism of grounding current generation in the core and clamp of converter transformers, which is much higher than that of ordinary power transformers in recent years. Firstly, factors such as the connection type, grounding method, iron core type, voltage level, voltage harmonics, DC bias and age of the converter transformer are taken into consideration for mechanism analysis. Then, the model of the HVDC system was established and the grounding current of the converter transformer was analyzed and calculated. Finally, the on-site grounding current was compared with the calculated results to verify the correctness of the mechanism proposed in this paper.