Dual Zero-Crossing Detection Control Strategy for Power Electronic on-Load Tap Changer of Distribution Transformer

Conventional on-load tap changer (OLTC) in power transformer employs mechanical switch, which suffers from electrical contact wear, mechanical component degradation, and speed limitation. Power electronic OLTC (PE-OLTC) has been proposed to improve performances during the voltage regulation, but an effective switching control strategy is required. In this paper a dual zero-crossing detection (DZCD) control strategy for power electronic on-load tap changers based on Insulated Gate Bipolar Transistor (IGBT) in distribution transformer is proposed. The proposed strategy mitigates the stress on IGBT during the voltage regulation process and overcomes the drawbacks of mechanical OLTC. The simulation model is built to validate the effectiveness of the proposed DZCD control strategy.