Siemens has won its largest order to date in Europe for its Fusesavers vacuum circuit-breakers. The deal worth €1.5m is also the first one from the UK.

Distribution network operator UK Power Networks has hired Siemens to equip parts of its overhead-line system with 600 of the vacuum circuit-breakers and 200 remote control units.

The Fusesaver vacuum circuit-breakers will be installed directly on overhead cables to minimise the number of customers affected in the event of a fault. This, says Siemens, will minimize installation and maintenance costs while significantly improving supply reliability and grid stability.

“This order is an important milestone in the development of the European market for the Fusesaver,” said Stephan May, chief executive of medium voltage systems at Siemens. “UK Power Networks is an important partner for us.”

Headquartered in London, UK Power Networks delivers electricity to the capital, the southeast and the east of England to approximately 8.2 million homes and businesses.

Distribution grids on the medium-voltage level can be installed both above ground and below ground. Many countries, such as the US, Australia and the UK, distribute their medium-voltage electricity using mainly outdoor distribution grids.

Siemens said it developed the Fusesaver to protect and improve the supply reliability and stability of these networks. The equipment can be installed in series with existing fuses. If a temporary fault occurs, such as a lightning strike or a tree branch on the line, the vacuum circuit-breaker upstream from the fuse opens and protects it from damage.

“Since a fuse cannot distinguish between temporary and continuous faults, it needlessly interrupts the circuit for a long period of time in 80 per cent of cases,” said May. “The Fusesaver can also completely replace the fuse, as in the UK Power Networks’ system. Temporary faults thus only lead to very short interruptions of the power supply. To avoid more extensive damage, the Fusesaver interrupts continuous faults until the cause of the fault has been eliminated.”

Matthew Corbridge, a network development engineer at UK Power Networks, said the Fusesaver “eliminates the number of maintenance deployments almost entirely”.

“In our continuing efforts to reduce the number of power cuts caused by a range of factors, we needed a cost-effective solution in order to ensure a reliable power supply for customers on the main lines. The Fusesaver meets these requirements with its highly flexible scalability and its easy installation.”

The Fusesaver is equipped with a wireless communication interface, over which the control and measured data can be transmitted to a PC or the control desk. This establishes the prerequisites for a smart grid. The breaker weighs 5.5 kilograms and is one of the fastest reclosable vacuum circuit-breakers on the market. It minimizes installation, operating and maintenance costs for outdoor distribution grids while increasing supply reliability and the personal safety of the grid operators.