Core Loss Distribution of Anode Saturable Reactor using J-A Dynamic Hysteresis Model

The anode saturable reactor (ASR) used in high voltage direct current (HVDC) converter valves generates humongous losses in working condition, which affect the safety of the converter valves. This paper estimates the core loss of ASR based on the J-A dynamic hysteresis model. The parameters of the J-A hysteresis model are optimized by using improved particle swarm optimization (PSO) algorithm, and the proposed method is verified in predicting the hysteresis losses and non-neglected eddy current and excess losses in cores according to the comparation results between measured and simulated losses in a grain-oriented (GO) silicon steel. By combining the proposed model with the finite-element method (FEM), the simulation model of single core-coils in ASR is constructed, and both the magnetic flux density and electrical stress of each mesh element in turn-on and turn-off transient states are obtained. The consequence shows that the maximum instantaneous loss density can reach up to 54.46 MW/m
³
when the coil current cross through 0 in turn-off state, while the relatively high core losses appear in the inner fillet, ends and vertical yoke near the air gaps, where the maximum losses can reach up to 63.8 W/kg.