Research on on-line monitoring technology of characteristic gas in vacuum on-load tap-changer oil

Abstract:
Breakdowns of vacuum on-load tap changer (OLTC) occur frequently in recent years, which have seriously affected the safe and stable operation of the electric power system. Dissolved gas analysis (DGA) is an effective method to diagnosis the latent faults of vacuum OLTC.However, the current periodic test mode not only aggravates the burden of operation and maintenance personnel, but also makes it difficult to detect the possible internal hidden dangers of the vacuum OLTC in time. In this paper, on the basis of analyzing the failure cases of vacuum OLTCs and the DGA data of multiple vacuum OLTCs in operation, it is concluded that acetylene is the main characteristic gas that reflects the operating status of vacuum OLTC. Then this paper proposes a vacuum OLTC acetylene on-line monitoring device based on the combination of membrane degassing and laser photoacoustic spectroscopy (PAS) detection technology, and introduces the main technology and performance indicators of the device. Finally, this paper verifies the effectiveness of the vacuum OLTC acetylene online monitoring device through the actual case of on-site test operation.