Totally metal enclosed switchgear system is designed for indoor installation & substations. They can be put together to form a single or double-bus switchboards. The system is highly reliable & safe to operate.
The standard cubicle is made up to 2-4 mm thick steel sheets formed into angles. The side sheets of the adjacent cubicles are highly insulated and the switchboard is closed off on either end, which can be fitted in the most limited spaces. Due to the rugged construction it can be delivered safely by truck or ship.
All the cable terminations are accommodated on the cubicle floor and all the internal equipment can be reached from the front.
Pressure relief of the compartments are provided by openings at the top. In case of any flashover inside the cubicle, the flaps will bend and the gases can escape. The high & low voltage compartments are separated from each other by an earthed steel sheet.
All the relays and other protective and signaling equipment are placed in the relay cabinet.
METAL-CLAD HIGH VOLTAGE SWITCHGEAR
The type tested GEN switchgear system, comprises different circuit configurations. All the different forms in turn, are satisfying the safety demands and are in compliance with the specifications.
The design basically, utilizes single bus-bar metal-clad switchgear without disconnectors, featuring WITHDRAWABLE circuit breakers and other circuit elements like current transformers, voltage transformers and earthing switches. GEN range switchgear are rated up to 36 kV. The circuit breakers trucks are ruggedly constructed and can be equipped with min-oil, SF6 or Vacuum type circuit breakers. All the control functions of the circuit breaker are transferred to the main cubicle through a control plug. The circuit breaker can perform all its functions in the operating or test position. The truck is grounded through a bus at all positions of the breaker. The switchgear is divided into four compartments:
- The circuit breaker section.
- The bus-bar section.
- Current transformer and the outgoing cable section.
- Relay compartment.
All these sections are separated from each other by sheet metal or fiber reinforced plastic sheets depending upon the requirements.
All the cubicles are being tested before delivered from the factory.
ADVANTAGES OF THE SYSTEM
- In case of malfunction the circuit breaker can be replaced immediately with a spare.
- Undamaged insulation capacity even after overtime service.
- With additional insulation & internal partitioning, the advantages can be further reinforced.
- The high voltage zones of the system are fully isolated & insulated, ensuring shock protection even if the truck is driven out of the cubicle.
- The switchgear truck has an electrical inter â€“ locking system which trips the breaker in an attempt to change the position of the truck.
- The circuit breaker truck can be easily moved between test, isolation & service positions.
- In service position, the breaker can be locked to prevent undesired operation.
- During in & out movements of the truck, the isolating contacts can be easily connected or disconnected.
- Operations are carried out in order.
- In test & isolation positions, the length of the distance between the fixed & moving contacts provide the necessary specific safety measures.
THE CIRCUIT BREAKER TRUCK
It is constructed from welded sheet steel which forms a rigid & strong body, protected against corrosion. The trucks carrying the breakers are provided with plastic rollers to facilitate motion.
The mechanical interlocking system between earthing units ensures further advantages.
ADDITIONAL EQUIPMENT FOR THE CUBICLES:
If required, the switchgear truck can be equipped with an oil-collecting pan to prevent oil escaping in case of a malfunctioning.
Additional insulation may be provided for the isolating contacts.
Besides the glass window in the door, a protective bar can be added to prevent accidents in the high voltage zone.
Special cable connections can be installed to connect the parallel cables to the system.
Double or multiple busbar systems can be provided.
The cable termination chamber can be provided wit a pressure relief system.
All metal parts are degreased chemically and painted with epoxy polyester powder coating.
Earthing & short-circuiting systems can be installed.
- Short-circuiting & earthing switches to earthing with insulated copper cables.
- Three-pole earthing switches to earth & short circuit the outgoing circuits. Earthing truck to earth the busbars, plus to earth the circuit (by remounting the contact arms).