Product Overview
The TG3-35Q/180×180×550 3AV3 Wall Bushing is an epoxy resin cast indoor high-voltage wall bushing designed for 35 kV and 40.5 kV withdrawable switchgear, switchgear cabinets, and other complete electrical equipment.
It is mainly used where live conductors pass through grounded partitions, equipment enclosures, or walls. The bushing provides insulating support, electric field shielding, and an electrical connection transition, helping ensure the safe and stable operation of high-voltage power systems.
Technical Specifications
| Parameter | Specification |
|---|---|
| Rated Voltage | 40.5 kV, suitable for 35 kV systems |
| Rated Frequency | 50/60 Hz |
| Mounting Dimensions | 180 × 180 mm flange opening |
| Overall Height | 550 mm |
| Material | Epoxy resin with a glass transition temperature of ≥105°C |
| Creepage Distance | ≥810 mm |
| Power-Frequency Withstand Voltage | 95 kV for 1 minute |
| Lightning Impulse Withstand Voltage | 185–200 kV peak |
| Partial Discharge | ≤3 pC at a test voltage of 4.5 kV |
| Rated Current Range | 1,250–2,500 A, customizable |
| Structural Design | One-piece epoxy resin casting with an integrated shielding layer |
Product Features
Excellent Insulation Performance
The bushing is manufactured using an integrated epoxy resin vacuum-casting process. A metal shielding layer is embedded inside the structure to distribute the electric field evenly, suppress partial discharge, and improve resistance to contamination and moisture.
Compact and Reliable Structure
The central flange mounting structure and upper and lower shed-type external insulation sections provide sufficient creepage distance while fitting the limited internal space of withdrawable switchgear.
The product offers high mechanical strength and reliable resistance to vibration and impact.
Maintenance-Free Design
The insulating surface provides good hydrophobicity and ageing resistance. No regular application of anti-pollution coatings is required. Routine surface cleaning is normally sufficient to maintain reliable insulation performance and reduce maintenance costs.
Wide Compatibility
The product is compatible with 3AV3 standard switchgear configurations. Different rated currents and mounting dimensions can be customized to meet the requirements of various indoor high-voltage electrical assemblies.
Safe and Environmentally Friendly
The product contains no insulating oil or SF₆ gas, eliminating the associated risks of leakage and explosion. It is suitable for environmentally responsible high-voltage electrical equipment.
Applications
- Suitable for indoor AC high-voltage distribution systems with a rated voltage of 35 kV or 40.5 kV and a frequency of 50/60 Hz.
- Mainly used in withdrawable switchgear, high-voltage switchgear, ring main units, box-type substations, and other complete electrical equipment.
- Used as an insulating and connecting component where busbars or cables pass through equipment enclosures or grounded partitions.
- Suitable for indoor high-voltage locations such as power stations, substations, and distribution rooms in industrial facilities.
- Provides insulation, separation, support, and secure connection between live conductors and grounded structures.
Operating Conditions
Normal Operating Environment
- Ambient temperature: -5°C to +40°C. Customized versions are available for special environments.
- Relative humidity: ≤85% at an ambient temperature of 20°C.
- Installation altitude: ≤1,000 m. For installations above 1,000 m, derating or a customized high-altitude version is required.
- Installation location: indoor.
- The installation environment should be free from severe vibration, flammable or explosive substances, corrosive gases, heavy dust, and conductive dust.
Extreme Operating Conditions
- Minimum ambient temperature: -25°C. A cold-resistant epoxy resin formulation is required.
- Maximum ambient temperature: +50°C. Derating is required to avoid accelerated insulation ageing.
- Maximum installation altitude: 3,000 m. A reinforced high-altitude version is required.
Prohibited Operating Environments
- Locations containing corrosive gases, vapours, dust, or explosive mixtures.
- Outdoor environments involving prolonged water immersion, heavy salt spray, or strong ultraviolet exposure.
- Areas with a seismic intensity above Level 8 unless additional mounting reinforcement is provided.
Installation and Maintenance Precautions
- During installation, ensure that the busbar or cable passes through the centre opening of the bushing. The conductor must not scrape against or press on the inner wall.
- Tighten the flange bolts evenly to prevent uneven mechanical stress, which may cause cracking or sealing failure.
- Inspect and clean the insulating surface regularly. Remove accumulated dust and oil to prevent a reduction in the effective creepage distance.
- If surface cracks, discharge marks, or abnormal temperature rise are detected during operation, stop the equipment immediately and carry out an inspection and repair.
