Unique switchgear for high currents

December 2015

Siemens is developing the world’s first air-insulated generator switchgear with vacuum circuit-breaker technology equipped with short-circuit breaking capacity of up to 100 kiloamperes (kA) at 24 kilovolts (kV).

The switchgear, type HB3-100, protects operating equipment such as electrical generators and transformers against overvoltage and short-circuit conditions and serves to support automated and demand-controlled operational management of power plants. These switchgear can be used in hydroelectric power plants, coal-fired units and combined cycle power plants as well as solar-thermal and geothermal power plants with electrical generating capacities of up to 400 megawatts (MW). Thanks to their low-maintenance vacuum circuit-breaker technology and resource-optimised development, the lifecycle costs of HB3-100 switchgear is up to 70 per cent less than existing solutions.

The products of Siemens HB3 series cover 80 per cent of all market requirements for this type of switchgear in new power plant units and retrofit projects.

The HB3-100 consists of a generator circuit-breaker in vacuum technology, disconnectors, grounding system and integrated startup disconnect switches. Unlike gas-insulated circuit-breakers, vacuum circuit-breakers interrupt the arc in a high-vacuum interrupter tube. The single-phase encapsulated unit can handle rated currents of up to 12,500 amperes (A) without forced cooling. It is maintenance-free up to 10,000 electrical switching events and 30 short-circuit interruptions at 100 kA. The hermetically sealed vacuum interrupters require no maintenance as a general rule and are resistant to any environmental influences.

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