Energy Reports (Nov 2022)
Research on the influence and suppression technology of micron foreign matter for gas insulated switchgear
Abstract
Breaking–closing of the circuit breaker inevitably produces micron metal dust, significantly affecting the internal insulation state of the GIS. This paper first analyzes the force characteristics of micron metal dust and its separation characteristics inside the circuit breaker, then builds a test platform supporting 520 kV power frequency withstand voltage and 1175 kV lightning impulse withstand voltage based on true type 363 kV GIS to investigate the influence of micron foreign matter on the insulation performance of GIS. Subsequently, ANSOFT is used to simulate the electric field distortion when there is micron metal dust inside the circuit breaker, and the influence of foreign matter on the degree of electric field distortion under the action of the flow field. The characteristics of the influence of micron foreign matter on the insulation performance of foreign matter inside the GIS are summarized. Secondly, using artificial micron foreign matter, the pulse current and the UHF methods are adopted to detect the discharge amount. The sensitivity of different detection methods to the discharge detection of the micron foreign matter is analysed, plus the partial discharge characteristics of the micron foreign matter under different voltages. Afterwards, based on the test results of micron foreign matter, two improvement measures are proposed, including the treatment of foreign matter inside the GIS and the dual-light source angiography inspection, so as to reduce the influence of micron foreign matter on the insulation status of the GIS. Finally, through the AC withstand voltage test of artificial embedded foreign matter and the insulation margin check under 1.1 times lightning impact, the effectiveness of the measures proposed in this paper is verified, thus providing technical support for certifying the impact of micron foreign matter on the insulation state during equipment operation and maintenance.
