New indigenous smart technology that can protect power grids from short-circuits

• Indian researcher has developed a unique innovation of a prototype of a smart system that can protect power grids from short-circuits by either automatically diverting the current into a parallel shunt (external resistance to bypass maximum current) or limiting a current surge by developing high resistance in the current path.
• These surges (fault current) damage the power grids causing major economic loss and disruption in the electricity supply.

• Prof. Satyajit Banerjee from the Indian Institute of Technology Kanpur (IIT Kanpur) and his group (Md. Arif Ali) have indigenously developed a unique innovation of a prototype of a Smart Superconducting Fault Current Limiter (SCFLsm), which has a circuit wherein a superconducting element has an array of hall sensors distributed around the superconductor.

• This technology is developed with support from the Advanced Manufacturing Technologies Program of the Department of Science & Technology (DST), Government of India is in the 4th stage of Technology Readiness level, and a national patent has also been filed for the same.

• The prototype can be incorporated in any of the large power sector companies who are working with their standard superconducting fault current limiters.

• Prof. Banerjee further plans to develop more efficient, large current automatic compact switches to divert current between superconductors to shunt.

• He also plans to develop predictive (intelligence) capability in his smart SCFL to automatically detect when one is nearing the threshold of formation of instability in the superconducting element or even to detect when the system is approaching the stage of fault occurrence.

• In this situation, the system will develop smartness and have sensors that will impart it something akin to intelligence to take rudimentary decisions.

• This will help diversion of the faulty as soon as it is detected by the smart sensors built into his SCFCLsm prototype.

• In recent years a new fault current limiter technology has been developed, namely, using superconductors.

• These are called as superconducting fault current limiters (SCFL).

• This technology developed is based on the property of superconductors offering zero resistance to currents up to a threshold current value, namely, the critical current.

• At currents beyond the critical current, the resistance of the superconductor becomes high.

• Thus, the SCFL’s operating principle is that when the fault current exceeds the critical current of the superconductor, its resistance becomes high.

• This reduces the fault current, and when the fault current reduces below the threshold critical current, the normal zero resistance mode offering operation returns.

• The SCFL is energy efficient in its operation. Companies in the west are already investing in superconducting fault current limiters (SCFL) technology.

• SCFL technology are expensive, with an approximate cost of each superconducting fault current limiter being in the range of Euro 1 million ~ Rupees 8,00,00,000 (Eight crores).

Benifits of SCFL

• SCFLsm allows for the continuous monitoring and mapping of the current distribution across the superconductor used inside it. * This enables the direct visualization of any instability setting in the SCFLsm during its operation. If any instability sets in the superconductor while the SCFLsm is operating at high currents, the mapping technology will detect its development.
• Subsequently, corrective action can be initiated to divert the current from the superconductor and protect the SCFL.
• Thus the common problem of failures of the superconductors experienced in conventional SCFL’s can be mitigated.
• The operation of this SCFLsm is completely automatic and independent of any manual intervention for resetting the system after a fault.

Short circuit

• It occurs when the current in the circuit rapidly rises and the electrical connection draws an excessive amount of current from the supply.
• During this time, the current has a very large magnitude.
• It occurs when the neutral and live wires come into contact.
• Short-circuit situations also often occur in power distribution networks like power grids, resulting in huge current surges that can damage the power grids as they are not designed to handle the large surge current.