An extra-high voltage electric porcelain outer insulation outlet bushing

Abstract

Disclosed is an ultra-high voltage electroceramics external-insulation lead-out bushing, which can be applied to such a device as an ultra-high voltage GIS, a tubular busbar and a circuit breaker. The bushing comprises a ceramic bushing, a grounding flange (1) and a conductive rod (3) arranged in the centre of the ceramic bushing. A cylindrical grounding electrode (4) is provided between the conductive rod (3) and the grounding flange (1). The ceramic bushing at least has two adjacent sub-bushings (5, 6). The sub-bushings (5, 6) are fixed to each other as a whole via a transition member (7). A cylindrical intermediate electrode (8) penetrating the sub-bushing (6) therebelow is provided between the grounding electrode (4) and the conductive rod (3). The intermediate electrode (8) is isolated from the grounding electrode (4) and the conductive rod (3). This solution can significantly improve the electrical performance of the bushing, and in particular, improve the wet flashover voltage, the bending strength, etc. of the bushing, while reducing manufacturing difficulties and manufacturing costs of the ultra-high voltage ceramic bushing.

Description

technical field [0001] The invention relates to an ultra-high voltage bushing, in particular to a porcelain jacket outlet bushing which can be used on busbars, GIS, circuit breakers and similar equipment. Background technique [0002] At present, there are two types of outer insulation for 550kV and above UHV circuit breakers and GIS outlet bushings: electric porcelain and composite. For outlet bushings with electric porcelain as the outer insulation, the porcelain bushings are basically tower-shaped structures (also known as cones). For 750kV products, the height is above 7m. Due to the technical characteristics of the molding and firing stages in the manufacturing process of the electric porcelain bushing, the height of the fired electric porcelain element does not exceed 2m, so the porcelain bushing of 550kV and above is made of several single-section porcelain bushings through inorganic bonding for secondary firing. The higher the porcelain piece, the higher the difficu...

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Problems solved by technology

In addition, since the grounding electrode will not be made too high, generally not more than 20% of the height of the porcelain sleeve (too high will cause the potential difference between the grounding electrode and the outer insulating surface of the porcelain sleeve to be too large and cause breakdown), so the voltage of the outer insulation The distribution is very uneven. Less than 20% of the height of the porcelain bushing at the lower end accounts for more than 50% of the distribution of the external insulation voltage. In the rainy state, the pagoda-like shape makes the rainwater at the lower end very dense, so the lower end is very prone to wet flashover

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