What is thought to be the longest switch panel in Europe is being installed by utility network operator 24seven at the South London electricity grid site in Deptford.

The 72-section switchgear is 42m long and housed in a new, purpose-built switching house.

The switch panel’s function is similar to that of a light switch, only on a larger scale and operating at many times the voltage and power.

The switch panel is just one component of an £8m enhancement to the Extra High Voltage (EHV) network supplying office buildings currently under construction at Canary Wharf, the Docklands Light Railway and the local network serving South London.

The Canary Wharf site is expanding with the construction of office towers for Citibank, HSBC and Morgan Stanley Dean Witter. Two of the sites alone have an additional electrical demand in excess of 20 MVA, the equivalent power demand of 20 000 homes.

This additional load is being fed by 18 new HV feeders running from the Deptford Grid sub-station on the opposite bank of the Thames through an existing tunnel beneath the river.

These feeders will supply an additional 78 MVA of capacity to the Canary Wharf area, making a total of 228 MVA .

The cables will be connected to the new switchboard supplied by three new transformers, each with a capacity of 66.6MVA, which are currently being constructed at Deptford.

The 72 sections that make up the Siemens switch panel have had to be connected together in a straight line, rather than in the customary horseshoe shape, in order to fit into the restricted space available.

The switch panel is a Siemens Type 8DA10 single busbar, metal enclosed, SF6 insulated 12kV.

Commented Steve Slade, site manager, “One third of the increased load at Deptford will meet the massively increased demand on Canary Wharf while the rest will upgrade the network around Deptford to meet additional demand and will replace older sub-stations in South London.

“This is an exciting project because we’re not only installing state-of-the art equipment on the switch panel, which will enable us to rapidly restore power following a fault, but we’re replacing two oil-filled 22kv transformers which have a fascinating history. They were built in 1927 and 1929 by Ferranti, who constructed the original, historic Deptford power station.”

24seven’s contractor at Deptford is Murphys Ltd.

24Seven was set up as a joint venture between London Electricity (owned by Electricité de France) and TXU Europe in April 2000. On Monday TXU said it had sold its 50 per cent stake to London Electricity along with its Eastern Electricity distribution network.