Medium voltage air-insulated arc resistant switchgear
BVK-A-38
General
BVK–A-38 is a metal enclosed, air insulated switchgear with a withdrawable vacuum circuit breaker and a single busbar system. Switchgears are type tested for the 38kV rated voltage and up to 1250A rated current . All standard switchgear types have a width of 1400mm, and are designed for a freestanding indoor installation.
The switchgear with a withdrawable circuit-breakers for indoor installation is suitable for:
- Power stations
- Transformer stations
- Switching substations
Technical characteristics
Constructions
All metal parts are made from steel, inox or galvanized sheet steel, with thickness of 2, 2.5 and 3mm. The anticorrosive protection is made by powder-coating in the color of grey - RAL 7032.
Functionality, safety and protection against electrical shock and ingess of solid foreign bodies is achieved by:
Complete enclosure of the panels in all operating states
- Internal metal compartments with enforced operation shutters
- Standard version degree of protection IP40/IP20, with IP31 for LV compartment
- Mechanical switchgear interlocks
- Functional insulating of all electrical conducting parts
Note: All interlocks are electro-mechanical with preventive, key-operated access shutters:
- Operating levers can only be inserted when the interlocking conditions are fulfilled
- This prevents impermissible overstraining of the interlocking mechanisms
Electrical characteristics
All electrical parts are copper and copper coated with silver. Adequate electric strength of BVK-A-38 switchgear is assured by:
- Sufficiently large air gaps between phases and earth
- Suitable busbars shape
- Suitable insulation elements
- Ribbed insulators in cast resin, with high resistance to pollution
Maintenance
Minimum maintenance effort is assured by:
- Total enclosure under all operating conditions
- Use of proven, maintenance-free vacuum switching devices
- Using main elements with draw-out properties
Sections
The switchgear usualy consists of four compartments:
- Busbar compartment
- Withdrawable part compartment(s)
- Connection compartment
- Low voltage compartment
Busses
Commercially available flat copper on commercially available cast-resin insulators. Busbars are bolted with length according to panel width. Busbar compartment is continuous throughout the entire installation Transverse compartmentalization with respect to neighboring panels is possible.
Busbar insulation is not necessary because dielectric strength is also guaranteed without insulation.
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Terminal compartment
Access to the compartment is possible from the back and from the bottom. Earthing and short-circuiting is done by earthing switch directly at the point of connection. Attachment of a fixed-mounted voltage transformers within the current transformer protection zone is possible.
It can have various draw-out sections:
- Withdrawable vacuum circuit-breaker section
- Withdrawable vacuum switch section
- Withdrawable disconnector-link section
- Withdrawable metering section
Operating cabinet
Use for accommodating the devices for protection, control, adjustment and metering. IP31 level of protection. Shock-proof partitioning from the high-voltage section. Pressure-resistant partitioning from the highvoltage section. Control wires of the panel are flexible and have metal tubes for conections with other compartments. Electrical operation and switch position indication on low-voltage compartment
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Nominal values
| Rated voltage | kV | 38 |
| Rated frequency | Hz | 50 |
| Short-duration power frequency withstand voltage / 1min. | kV | 70 |
| Lightning impulse withstand voltage | kV | 170 |
| Short-time withstand current(3 sec.) | kA | 25 |
| Peak withstand current | kA | 63 |
| Normal current fo busbars | A | 1250 |
| Normal current of feeders | A | 630/1250 |
| Width | mm | 1400 |
| Depth | mm | 2450 |
| Height | mm | 2450 |
| Ambient temperature | °C | 50 |
Standards
BVK-A-38 type switchgear for indoor installation complies with the following valid standards:
- IEC 60694
- IEC 62271-200
- IEC 60529
- IEC 62271-100
- IEC 62271-102
- IEC 60044-1
- IEC 60044-2
- IEC 60282-1
- IEC 61243-5
