Simulation of HVDC system disturbances with reference to the magnetizing history of the convertor transformers

Following HVDC (high-voltage direct-current) system disturbances, the converter transformers may be subjected to overexcitation, DC magnetization, and in-rush effects, all of which must be accurately represented in dynamic simulation studies. A description is given of practical ways of modeling the magnetic history of the converter transformer. The authors use them to assess the relative importance of saturation and hysteresis when simulating converter recoveries from large disturbances