Optimization-enabled EMT modeling for transformer impulse test

A novel method is proposed to enhance the performance of optimization algorithms to obtain impulse generator settings. This method resolves two major problems encountered in tradition optimization-enabled electromagnetic transient simulation (OE-EMTS) approach. First, a new technique is introduced to model a transformer in an electromagnetic transient (EMT) simulator. This technique uses the frequency response of the transformer to calculate time-domain quantities without synthesizing the transformer circuit. As a results, most of the major issues attributed to the frequency-response based EMT modeling are solved, such as appearance of negative resistive elements in the synthesized circuit and generation of highly complex/dense branch networks. Second, multiple optimization algorithms are implemented to optimize impulse generator settings. Combination of multiple algorithms has balanced the effects of convergence speed and accuracy for better results. The proposed approach is verified by two case studies, involving different resistor arrangements. The simulated waveforms are compared with those obtained from measurements.