OverviewBSHB-12 environmentally friendly gas ring main unit is an intelligent, environmentally friendly, and fully operational device with high operational safety reliability, suitable for 12kV secondary distribution systems. It features full insulation, long lifespan, maintenance-free operation, small footprint, safety and reliability, and is not affected by the environment. It is widely used in industrial and civilian ring main and terminal power supply. It is particularly suitable for small secondary distribution stations, switching stations, industrial and mining enterprises, airports, railways, commercial areas, high-rise buildings, highways, subways, tunnels, and other fields. Especially in high altitude, humid, cold, and low-lying special environments. The product is not only widely used domestically but has also been exported to Western Europe, Northern Europe, and other countries.
"Catalogue of the First Batch of Key New Technologies Promoted by the State Grid Corporation of China" has clearly stated that environmentally friendly gas ring main units have a trend towards completely replacing SF6 gas-insulated ring main units.
In recent years, with the general improvement in design quality, environmental performance, and manufacturing technology of environmentally friendly gas ring main units, product quality and standardization have met user requirements. Through the promulgation of DL standards and the gradual expansion of usage, environmentally friendly gas ring main units will become the mainstream product in the construction of smart grids.
Model Description
Usage environment☆ Altitude: ≤5000m
☆ Ambient temperature: -40℃ to +65℃
☆ Relative humidity: Daily average ≤95%, Monthly average ≤90%
☆ Seismic intensity not exceeding 8 degrees
☆ Installation site free from fire, explosion hazards, chemical corrosion, and severe vibration;
☆ For use in special environments, please consult with our company
Features☆Simple structure, flexible operation, reliable interlocking, and convenient installation ☆Achieve "zero emission" of greenhouse gases and environmental protection
☆Use rectangular contact springs for stable force values and long mechanical and electrical lifespan of the product
☆Wide-angle lens equipped with LED light source, which can effectively observe the three working conditions of the isolating switch: closing, opening, and grounding, facilitating maintenance and repair by operation and maintenance personnel. The lens barrel is made of aluminum alloy, which has high strength and avoids the risk of primary circuit sealing failure caused by aging.
☆ Wide-angle lens with built-in lighting system, facilitating observation of isolated fractures.
☆The main switch is designed with buttons for convenient and simple operation. The button structure is made of zinc alloy material to prevent aging and failure.
structural analysisThere are primarily three ways to enhance insulation performance by optimizing the structure to reduce air gaps: ① improving the shape of the conductor; ② adding insulating barriers; and ③ increasing the creepage distance on the surface. Under the same air gap conditions, appropriately increasing the fillet radius and using a symmetrical electrode structure can reduce the electric field non-uniformity coefficient and enhance the withstand voltage. Therefore, the busbar utilizes rectangular copper bars with R-shaped corners, and the burrs on the rounded surface of the surrounding edges are removed.
In an extremely uneven electric field, installing insulating boards or shielding covers at appropriate locations can significantly enhance the breakdown voltage of the gap under certain conditions. Additionally, to increase the surface creepage distance between conductors and between conductors and the ground, it is advisable to use expansion connectors and incoming and outgoing line sleeves with built-in umbrella skirts and spacers, as shown in Figures 6 and 7 respectively. The spacers can shield the uneven electric field at the conductor connection part within the space enclosed by the spacers, effectively optimizing the switching electric field and reducing the insulation distance. The umbrella skirts can effectively increase the surface creepage distance of insulation and enhance the voltage withstand level.
The power frequency withstand voltage test is used to inspect the insulation level of equipment, prevent insulation accidents, and verify whether the equipment meets operational requirements. Conducting a power frequency withstand voltage test at a specified value under zero gauge pressure, while gradually verifying the obtained limit value, can meet the operating conditions of busbar copper bars at altitudes ranging from 1000 to 1800 meters as shown in Figure 1.
Main technical parameters
| Project |
V Unit |
C Unit |
F Unit |
| Rated voltage（kV） |
12 |
12 |
12 |
| Rated current（A） |
630 |
1250 |
630 |
125 |
| Rated frequency（Hz） |
50 |
| Power frequency withstand voltage (KV) between phases, phase to ground/open circuit |
42/48 |
| Lightning impulse withstand voltage (KV) between phases, phase to ground/fracture |
75/85 |
| Rated short-circuit breaking current（kA） |
25 |
31.5 |
|
31.5（fuse） |
| Rated cable charging breaking current（A） |
25 |
31.5 |
10 |
|
| Rated short-time withstand current（kA） |
25 |
31.5 |
25 |
|
| Rated short-time withstand time（s） |
4 |
4 |
4 |
|
| Rated peak withstand current（kA） |
63 |
80 |
50 |
|
| Rated short-time making current（kA） |
63 |
80 |
50 |
|
| Rated transfer current（A） |
|
|
3150 |
| Rated exchange current（A） |
|
|
3700 |
| Internal arcing test AFLR level（kA/s） |
25/0.5 |
31.5/0.5 |
| partial discharge（pc） |
≤20 |
| Protection level cabinet/switch |
IP4X/IP67 |
| Main circuit resistance（μΩ） |
≤150 |
≤150 |
≤700 |
| Mechanical lifespan (times) of main switch/disconnector |
10000/3000 |
10000/3000 |
5000/3000 |
