Effect of O2 on AC Partial Discharge and Decomposition Behavior of C4F7N/CO2/O2 Gas Mixture

• Published in: IEEE transactions on dielectrics and electrical insulation Vol. 28; no. 4; pp. 1440 - 1448
• Main Authors: Ye, Fanchao, Zhang, Xiaoxing, Li, Yi, Yao, Yuhang, Xiao, Song, Xie, Cheng, Shao, Xianjun, Sun, Xiang
• Format: Journal Article
• Language: English
• Published: IEEE 01.08.2021
• Subjects: C 4 F 7 N/CO 2 /O 2 gas mixture; Correlation; decomposition behavior; Discharges (electric); Insulation; optimal oxygen addition; partial discharge; Partial discharges; Spectroscopy
• ISSN: 1070-9878; 1558-4135
• DOI: 10.1109/TDEI.2021.009626

This paper focus on the influence of oxygen on the partial discharge (PD) and decomposition characteristics of C 4 F 7 N/CO 2 /O 2 gas mixture as eco-friendly gas insulating medium. The PD characteristic parameters and phase resolved partial discharge (PRPD) patterns of C 4 F 7 N/CO 2 /O 2 gas mixture are, respectively, extracted and constructed. The influences of oxygen content and applied voltage on the PD and decomposition characteristics of C 4 F 7 N/CO 2 /O 2 gas mixture are investigated based on gas chromatography-mass spectrometry (GC-MS). We find that the addition of 2-4% O 2 to C 4 F 7 N/CO 2 gas mixture can significantly inhibit the negative half-cycle PDs and the generation of most by-products (CF 4 , C 2 F 6 , C 3 F 6 , CO, C 2 F 6 O 3 , CF 3 CN, C 2 F 5 CN, C 2 N 2 ). With the oxygen content higher than 6%, the accumulation discharge magnitude and discharge repetition rates of C 4 F 7 N/CO 2 /O 2 gas mixture increase sharply, accompanying the intensification of decomposition and deterioration of insulation strength. There is a positive correlation between the mean discharge magnitude and gas mixture decomposition intensity. To avoid the serious impact of PD fault on gas insulated equipment (GIE), the optimal oxygen addition in C 4 F 7 N/CO 2 /O 2 gas mixture should not exceed 6%.