An Improved Control Scheme for On-load Tap Changers with Reduced Harmonics Injection

The static on-load tap changer is a better alternative than conventional on-load tap changers. The proposed solution involves the use of a compensation transformer and a bidirectional diode-insulated-gate bipolar transistor combination with appropriate switching techniques. Any required load voltage can be obtained with less injection of harmonics to load voltage waveform, and the response is practically instantaneous. The general structure of an electronic tap changer and the proposed modified model with voltage controller are presented. A gravitational search algorithm-based soft computing technique is used for the compensating voltage to optimize the switching angles for minimization of the output voltage harmonics. Various simulation and experimental results are presented to validate the proposed concept.