Three phase bowl insulators for 252kV and 363kV main busbars

The three-phase bowl insulators (for main busbars) used in 252kV/363kV GIS equipment are the core components of high-voltage gas insulated switchgear, and their design must meet the insulation, mechanical, and environmental adaptability requirements under high voltage levels. The following is a comprehensive technical analysis:
1、 Design Features and Optimization
Structural Design
Adopting a three-phase common box structure, the electric field distortion is reduced by optimizing the geometric shape of the bowl insulator (such as the concave curvature radius), and the uniformity of the electric field between the three phases is improved by more than 20%
Cancel traditional metal shielding rings (such as 252kV products), reduce SF6 gas consumption by 15%, and avoid the risk of partial discharge
Materials and processes
Adding alumina or titanium dioxide fillers to epoxy resin composite materials, designing a gradient dielectric constant (ε=3.98-14.58), and increasing flashover voltage by 13.8%
3D printing combined with vacuum casting technology to achieve complex dielectric structures, with mechanical strength meeting 1.5 times the rated pressure water pressure test
2、 Performance parameters and validation
Electrical performance
252kV product power frequency withstand voltage 230kV, lightning impulse withstand voltage 550kV; 363kV product power frequency withstand voltage 300kV, lightning impulse withstand voltage 800kV
Partial discharge capacity ≤ 5pC, flashover voltage can still increase by 6.7% in the presence of metal foreign objects
Mechanical performance
Maximum deformation ≤ 0.45mm, interface stress below 70MPa, verified through hydraulic failure test
3、 Typical Applications and Fault Analysis
Application scenarios
Connection of 252kV/363kV GIS main busbar, such as urban substations, industrial power supply systems (such as automobile manufacturing plants, motor manufacturing industries)
Used in conjunction with isolation switches (such as GW22B-363D type) and grounding switches (such as JW10-550 type)
Fault statistics
The discharge caused by foreign objects in 252kV GIS faults accounts for 29%, and the failure rate of equipment that has been in operation for less than 5 years is as high as 89%
The risk of breakdown is significantly increased when metal shavings are arranged in the low potential region, and the partial discharge of sand particles is the highest

Note: Customization with drawings is available