310 / 2022-03-15 11:40:30

Harmonic Breaking Characteristics of Converter Transformer Vacuum On-Load Tap-Changer

on-load tap-changer,converter transformer,HVDC

Vacuum on-load tap-changers (OLTC) can compensate voltage fluctuation and control the trigger angle of converter valve in the best range, which is an important component of converter transformer. Different from the power transformer, due to the existence of harmonics, the rising rate of current flowing through the converter transformer is high, resulting in a high rising rate of recovery voltage on the vacuum interrupter. Therefore, it is necessary to study the harmonic breaking characteristics of converter transformer vacuum OLTC, so as to provide theoretical support for the design and selection of vacuum interrupter. This paper introduces the topology of vacuum OLTC, and then analyzes the electrical stresses on the vacuum interrupters during OLTC switching process. A ±800 kV LCC-HVDC system in PSCAD is also built to verify the correctness of the theoretical analysis. On this basis, the harmonic breaking characteristics are discussed.