Research on the Switching Arc Loss of on-Load Tap Changer

The on-load tap changer (OLTC) switching arc will affect the life of the contact, so it is necessary to test its working condition. Based on DQ coordinate transformation, fundamental wave component extraction, and wavelet algorithm, proposed an OLTC arc detection method based on energy conservation theory in this paper. Used the fundamental wave component extraction algorithm extracted the transformer excitation parameters, and established the OLTC equivalent circuit by combining the Habedank arc model. Compared the differences between the follow effect and frequency calculation of simulated and measured waveforms, which were caused by the five orthogonal transformation algorithms, including Transport-Delay, Hilbert Transformation, Inverse Park Transformation, SOGI and Improved SOGI. The DQ coordinate transformation based on the Transport-Delay orthogonal converter is determined to calculate the active power of each part of the circuit. According to the principle of energy conservation, obtained the data of arcing loss under nine simulated conditions. Based on the simulation circuit, built the OLTC prototype and dSPACE hardware in loop simulation platform, and measured three load conditions. The sampling signal was filtered by the wavelet algorithm. Considering the measurement and calculation errors, the simulation and measured results show that the actual arcing power has a consistent change with the calculated value between different working conditions, and the maximum difference between simulation results and measured results is thirty times and ten times. It can distinguish the difference of arcing energy of diverter switch under different working conditions and has the measurability. Meanwhile, it verifies the effectiveness of this study, hoping to provide a theoretical basis for developing OLTC on-line contact detection system.