SF₆ decomposition components under different metallic free‐conducting wire‐type particles in positive DC partial discharge

Abstract

This study aimed to explore the common free‐conducting wire‐type particles that can produce severe partial discharge (PD) in DC gas‐insulated equipment. The experiment was conducted on the SF6 positive DC PD experimental system to determine the influence of the free‐conducting wire‐type particles of three kinds of metal materials (aluminum, 18/8 stainless steel, and copper) on SF6 decomposition. The change rules of five main characteristic decomposition components, namely, CF4, CO2, SOF2, SO2F2, and SO2, under different free‐conducting metal particles were obtained using gas chromatography–mass spectrometry quantitative detection. No significant correlation was observed between the formation of CO2 and the kinds of metal materials; however, the kinds of metal materials significantly influenced the formation of the other four kinds of characteristic gases. The differences in the physical and chemical properties of the metal materials caused the different characteristics of SF6 positive DC PD decomposition under different free‐conducting metal wire‐type particles. Findings provide an experimental basis for the diagnosis of fault‐type positive DC SF6 gas‐insulated equipment. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Characteristics of the Surface Charge Accumulation and Capacitive‐Resistive Electric Field Transition for an HVDC GIL Insulator

“…Currently, alternating current (AC) GIL has benefitted from a great deal of design and engineering experience after decades of development, while the development of HVDC GIL is far behind. Generally, high DC electric field stress and its concomitant problem of charge accumulation is a challenge for the electrical insulation system of HVDC equipment [5][6][7][8]. Support insulators and disc insulators, which play the roles of electrical insulation and mechanical support, respectively, are widely used in HVDC GILs.…”