Community Research and Development Information Service - CORDIS

Novel tape acts as fault current protector

Fault currents resulting from short circuits can damage electricity networks. Novel superconducting fault protection that simply reduces high-fault currents to manageable levels promises to keep the power on.
Novel tape acts as fault current protector
With increasing loads on mains power lines, ageing equipment and increasingly decentralised power generation and distribution, high short-circuit currents pose a major threat to energy security. The EU-funded ECCOFLOW project developed and produced a unique superconducting fault current limiter (SFCL).

Superconductor materials have zero resistance to the flow of electricity. However, they must be supercooled to demonstrate this property. In recent years, so-called high-temperature superconductors (HTSs) have been developed. Although high-temperature is somewhat of a misnomer given that they still require cryogenic temperatures, the temperatures are much easier to achieve and their modulation can turn the materials from superconducting back to resistive.

Exploiting this property and in contrast to a fuse, the SFCL does not stop electricity flow, it limits it to a safe value. During normal operation, the superconductors of the SFCL are easily and inexpensively cooled to around – 200 degrees Celsius with liquid nitrogen. When their critical current is exceeded, they self-actuate, suddenly losing superconducting ability and demonstrating high resistance that limits current flow to a predefined value.

The SFCL design consists of the HTS modules (based on a YBa2Cu3O7-d, or YBCO, superconductor tape), the cryostat, the bushings, the cooling system, the air coils and the circuit breakers. It is currently installed in Mallorca, Spain, and will be field-tested in the coming months.

Socio-economic studies based on existing grids in Spain as well as generic grids demonstrate the reliability, market potential and cost savings possible with the SFCL in the medium term. Electric utilities stakeholders across Europe have already expressed interest.

Incorporation of ECCOFLOW technology into existing and ageing electricity networks will enable no-resistance current flow under normal conditions while limiting dangerous fault currents in case of malfunction. It will keep power on for millions of Europeans, rain or shine, lightning or not.

Related information

Keywords

Surge protector, fault currents, short circuits, electricity networks, mains power lines, superconducting fault current limiter, YBCO
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