Research of Resonant Overvoltages in Power Plant Auxiliary Circuits

作者：Евгений Павлович Сафонов, Elena A. Ivanova, E. Yu. Zmaznov, N. G. Lozinova · 年份：2021 · DOI：10.1109/elconrus51938.2021.9396565 · 被引用次数：2 · 研究领域：Power Systems Fault Detection、Power Transformer Diagnostics and Insulation、High-Voltage Power Transmission Systems

Current-limiting reactors and transformers destructions in auxiliary network of 13.8 kV medium voltage (MV) took place at the 2488 MW HPP during operational switching on the adjacent 500 kV network. Arc overlap traces were found on the reactors and auxiliary transformers bushing (ATB). A theoretical pre-accident study resulted in the hypothesis about the resonant nature of the overvoltage, which caused an arc overlapping of the ATB and further provoked an overvoltage in the auxiliary reactor. Frequency characteristic full-scale measurement results showed that a 50-60 kHz high-frequency signal applied to the high voltage side phase of 500/13.8 kV transformer in 13.8 kV auxiliary network ramped up dramatically (9-10 times), which confirmed the hypothesis put forward. In response to this problem, it was proposed to install damping RC circuits at the auxiliary phases. High voltage tests have confirmed the effectiveness of RC circuits application to control this type of overvoltage.