A new automation system being installed in electricity sub-stations should reduce any power cuts in London to less than three minutes, said network operator 24seven today.

This automated electricity supply restoration system, Remsdaq LPN Automation Scheme, reduces minutes lost in a power failure to a fraction of what they might have been, according to 24seven. It is now being implemented across a wide area of London.

The system has already proved highly effective and has already operated twice in recent weeks, in Beckenham and Bromley. In the first incident, on 1 November, 1700 customers were restored automatically within three minutes. The second operation, on 6 November, ensured 2650 customers were restored in approximately one minute.

The automated system runs with software installed at sub-stations rather than a physical ‘add-on’ to underground cables. So far 547 circuits fitted with the software have been commissioned, with 862 being the ultimate goal.

Bob Jackson, 24seven’s Solutions Planning Engineer, explained, “Many customers lose their electricity supply for more than three minutes and more than half the faults in London are on the high-voltage network, so we’re fitting a system which targets interruptions on this high-voltage network.”

When a fault occurs on a cable, switches driven by the sub-station software automatically disconnects the faulty section and close in an alternative electricity supply within three minutes. From then onwards the control engineer in 24seven’s Operations Centre manages the fault as normal, using field staff to locate and repair it.

Commented Steve Shine, 24seven’s Director, Electricity Division, “We’ve created a unique automated restoration module, tailor-made for the London network. Substantial numbers of customers will benefit from an improved service as we strengthen security of supply in the capital.”

Installation at sub-stations included in the project began in early September and will continue until Christmas. Among the areas benefiting from the system will be Hackney, Epping Forest, Islington, Kensington, Southwark and Sydenham.

24seven serves 5.3m customers – domestic and business – within London and the Eastern region and operates 119 000 km of overhead lines and underground cables and 45 000 sub-stations.