Schneider Electric’s GHA Gas-Insulated CB Switchgear

In line with its goal of constant development and improvement in products and services, global specialist in energy management, Schneider Electric has introduced GHA gas-insulated circuit breaker switchgear offering safety, security, ecological and economic advantages.

“GHA provides an optimum solution for a variety of safe power requirements, with applications ranging from transformer substations to switching stations for primary power supplies. It also carries IAC classification,” says Isaac Kruger, manager: MV offer and technology at Schneider Electric South Africa.

“This is a ground-breaking development with GHA, offering high dependability, operating reliability, maximum operator safety and ergonomic operator guidance.”

Kruger adds that the switchgear suits a wide range of requirements and applications in public and industrial distribution networks, infrastructure projects, mining, metallurgy, petrochemical, oil and gas industries, railways traction power supply, container stations and ship-building.

Innovative design ensures a variety of equipment options and the GHA is designed to operate as a single or double busbar system, its modularity offering flexibility and a long, trouble-free service life.

“No gas-handling is required during installation, extension work or panel replacement and the busbar link is innovative and fault-tolerant, while its environmental compatibility offers simple and easy recycling. Erection, extension and disassembly are straightforward and the innovative B-Link busbar connection simplifies the process.”

The complete metal enclosure of all switchgear components provides maximum protection against accidental contact and a comprehensive interlocking system ensures maximum operator safety.

For secure operation, the active MV components are located in hermetically sealed, gas-filled compartments and are insensitive to aggressive atmospheres, dirt, dust and vermin. Protection against fire in the panel and prevention of contact oxidation are provided by SF6 insulating gas.

“Reliability is ensured by the application of mechanical or electronic gas monitoring equipment for each gas compartment, all of which have a pressure relief device,” adds Kruger. “Also contributing to overall reliability are the low number of static and dynamic seals, the high number of mechanical and electrical operations afforded by vacuum circuit breakers and the drive and interlocking system.”

Design is clear and compact offering easy access to all function groups, easy operation with ergonomic design, a visually highlighted control panel, logical operation and visual operator guidance for mechanical panel operation. Economic efficiencies are achieved through reduced space and surface area, short assembly times, minimised operating costs and maintenance-free gas tank constructed from stainless chromium-nickel steel.

“All of the HV parts are set in an SF6 atmosphere with slight over-pressure to protect against humidity and contamination irrespective of installation altitude,” says Kruger. “Ecological benefits include optimisation of material and energy consumption during manufacture and the absence of gas handling on assembly or switchgear extensions on either side. Recyclable materials are used for efficient disposal at the end of service life.”

Connection of the busbars from adjacent panels is through Schneider Electric’s innovative link system known as B-link. Maintenance free, it enables assembly without gas work at the customer site. Extensions or panel replacements within the panel assembly can be executed without gas handling or interference in gas-filled compartments.

“The potential-controlled, externally grounded, flexible and robust silicone insulated elements of the B-link system are simply assembled with minimal electrical field intensities. Busbars on the switchgear ends are also closed with voltage-proof terminations,” says Kruger.

“Finally, as a result of the reduced space requirements, the GHA switchgear minimises investment cost. Replacement of old conventional switchgear units with GHA in existing rooms is possible through step-wise commissioning of the GHA panels while disassembling the old switchgear, a factor that significantly reduces down time and overall costs.”