Composite post insulators for metro contact rails are gradually replacing traditional porcelain insulators and becoming the preferred equipment for metro power supply systems due to their excellent performance. Its design, manufacturing, and maintenance need to comprehensively consider various factors such as electrical, mechanical, and environmental factors to ensure the safe and stable operation of the metro system.
Insulators are one of the components of contact suspension in electrical systems, mainly used to suspend and support charged bodies, isolate charged bodies from grounding bodies, and provide insulation
In the city rail transit contact rail system, insulators insulate the contact rail from the structure and support and position the contact rail. Insulators can withstand the self weight of the contact rail and a short-term concentrated load of 150KG placed on the contact rail, as well as the impact load of the contact rail in the event of a system short circuit fault. Therefore, they need to have strong basic performance requirements
1. Its main functions include:
-Electrical insulation: prevents electrical short circuits between the contact rail and the supporting structure.
-Mechanical support: bear the weight of the contact rail and the dynamic load during train operation.
2. Composition of raw materials
Composite post insulators are typically composed of the following materials:
-Core rod: Made of high-strength glass fiber reinforced epoxy resin (FRP), it has high mechanical strength and good electrical insulation performance.
-Shed: Made of silicone rubber or ethylene propylene rubber, it has good weather resistance, UV resistance, and pollution resistance.
-Metal accessories: used to connect insulators with contact rails and supporting structures, usually made of corrosion-resistant aluminum alloy or stainless steel.
3. Performance characteristics
-Lightweight: The density of composite materials is much lower than that of ceramics, reducing the overall weight and facilitating installation and maintenance.
-High mechanical strength: The core rod has high tensile, bending, and compressive strength, and can withstand dynamic loads during metro operation.
-Corrosion resistance: Silicone rubber umbrella skirts have good chemical corrosion resistance and are suitable for harsh environments such as humidity and pollution.
-Impact resistance: Composite materials have good toughness and can resist mechanical impact and vibration.
-Excellent electrical performance: high insulation resistance and voltage resistance, ensuring safe operation in high voltage environments.
-Anti pollution flashover performance: The umbrella skirt design increases the creepage distance, effectively preventing pollution flashover phenomenon.
4. Structural design
-Shed structure: The umbrella skirt adopts a multi umbrella design to increase the surface creepage distance and prevent flashover in humid or polluted environments.
-Core rod and umbrella skirt combination: The core rod and umbrella skirt are tightly combined through high-temperature vulcanization process to ensure the stability of the overall structure.
-Metal accessory connection: Metal accessories are connected to the core rod through crimping or adhesive bonding processes to ensure mechanical strength and electrical performance.
5. Installation and maintenance
-Installation:
-Before installation, it is necessary to check whether the appearance of the insulator is intact and whether the metal accessories are firm.
-During installation, it is necessary to ensure the correct connection between the insulator, contact rail, and supporting structure to avoid mechanical stress concentration.
-Maintenance:
-Regularly inspect the surface of insulators for cracks, contamination, or aging.
-Clean the surface of the shed to prevent the accumulation of pollutants from affecting electrical performance.
-Regularly conduct electrical performance tests to ensure that insulation resistance and voltage resistance meet there quirements.
6. Advantages
-Advantages:
-Lightweight, easy to transport and install.
-Corrosion resistance, aging resistance, long service life.
-Good impact resistance, suitable for dynamic load environments such as metros.
7. Application
-Subway contact rail system.
-Urban rail transit power supply system.
-Electrified railway overhead contact system.
-8. Standards and specifications
The design, manufacturing, and testing of composite post insulators must comply with relevant standards, such as:
-International standard: IEC 61952 (Composite Insulator Standard).
-National standard: GB/T 19519 (Standard for Composite Insulators for Rail Transit).
-Industry standard: formulated according to the specific requirements of the metro system.