126-252kV GIS Insulation torsion bar

126-252kV GIS insulation torsion bar is a key transmission component in gas insulated metal enclosed switchgear (GIS), and its performance directly affects the mechanical reliability and electrical insulation performance of the circuit breaker. The following is a comprehensive technical analysis:
1、 Core functions and design requirements
Electrical insulation performance
It is necessary to withstand power frequency voltage and lightning impulse voltage (such as 550kV/950kV) from 126kV (rated voltage) to 252kV (rated voltage), and the surface electric field strength should be controlled below 15kV/mm
The material needs to have high dielectric strength (≥ 30kV/mm) to prevent surface discharge or breakdown
Mechanical transmission characteristics
It needs to withstand the impact load of opening and closing (such as 40kA short-circuit current breaking), with a dynamic response frequency range of 0-600Hz, and high-frequency components decay with increasing operation times
The mechanical lifespan should be ≥ 10000 times, and the fracture strength should meet the torque requirements of extreme working conditions (such as 550kV GIS isolation switch)
2、 Materials and processes
Mainstream material system
Fiberglass epoxy composite material: high mechanical strength, but fiber arrangement needs to be optimized to reduce the risk of crack propagation
Aramid/polyester fiber epoxy composite material: lightweight and fatigue resistant, suitable for high voltage levels of 252kV and above
Manufacturing process
Adopting compression molding sintering or winding process to ensure density ≥ 2.15g/cm ³, and enhancing surface insulation performance through plasma treatment
Key areas (such as the contact side bonding area) require stress concentration optimization design to avoid exceeding the maximum strain limit
3、 Technical Challenges and Solutions
Dynamic fatigue failure
Internal defects (such as delamination and cracks) are prone to occur under the impact of opening and closing, and reliability needs to be verified through impact fatigue testing (such as 100 full capacity short-circuit current tests)
Environmental substitution trend
Fluorine free environmentally friendly GIS (such as 126kV CO ₂ insulation equipment) requires higher requirements for the low temperature resistance (-40 ℃) of insulation torsion bars and needs to be adapted to the characteristics of new media
4、 Industry Applications and Standards
Typical application scenarios
126kV GIS: New Energy Power Generation Projects (such as Shougang Changzhi Steel Surplus Gas Power Generation Project)
252kV GIS: Ultra high voltage transmission project, which needs to meet standards such as DL/T 617-1997
Standard basis
Must comply with GB/T 11022-2020 "Common Technical Requirements for High Voltage Switchgear and Control Equipment Standards" and IEC 60694 standard

Note: Customization with drawings is available