Vibration and Audible Noise Characteristics of AC Transformer Caused by HVDC System Under Monopole Operation

• Published in: IEEE transactions on power delivery Vol. 27; no. 4; pp. 1835 - 1842
• Main Authors: He, Jinliang, Yu, Zhanqing, Zeng, Rong, Zhang, Bo
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic noise; Applied sciences; Audible noise; Bias; Circuit faults; dc bias; Direct current; Direct current networks; Electric potential; Electrical engineering. Electrical power engineering; Electrical power engineering; Exact sciences and technology; HVDC transmission; Manufacturing engineering; Monitoring; monopole ground return mode; Monopoles; Noise; Power networks and lines; power transformer; Power transformers; Studies; Substations; Transformers; Transformers and inductors; Users connections and in door installation; Vibration; Vibrations; Windings; Substation; Grounding; HVDC transmission; Connection; Factory; Power electronics; Experimental study; Power transformer; vibration; Long term; Sound pressure; Frequency characteristic; Audible noise; Acoustic noise; Direct current; dc bias; DC transformers; On line processing; monopole ground return mode; HVDC systems; Monitoring; Machine windings
• ISSN: 0885-8977; 1937-4208
• DOI: 10.1109/TPWRD.2012.2205409

When the HVDC system works in monopole ground return mode, dc current flows through the neutral of ac power transformer with the neutral grounded, which will enhance its vibration and audible noise. In this paper, dc bias experiments on ac power transformers carried out on 500-kV power transformers both in the transformer factory and the substation are described; the experimental results show how the vibration and audible noise of the transformer change under the dc bias current or windings voltage. The frequency characteristics of the vibration and audible noise of the dc-biased transformer are discussed under the conditions with and without loads. The direct connections between the vibration peak value and the dc bias current, and between the sound pressure and the dc bias current are revealed. Long-term online monitoring shows that the vibration of the transformer changes seriously even if there is not a dc system operating in monopole earth return mode, so when we analyze the influence of dc bias on the vibration and audible noise of the transformer, other influential factors should be expelled.