National Grid has completed upgrades at three substations, with new high-voltage equipment now connected at Cottam, Wylfa, and Willington.
The work has seen shunt reactors installed and energised at the sites, helping the network operator manage voltage levels and improve the stability of the transmission system.
While shunt reactors may not be the most recognisable part of the electricity network, they play an important role in managing reactive power on alternating current networks. In simple terms, they help absorb excess reactive power, supporting more reliable voltage regulation and reducing electrical stress on other more recognisable assets – think switchgear, cables and transformers.
Each of the newly installed units weighs around 130 tonnes, measuring more than seven metres long and almost four metres high.
The first of the three reactors was energised at Cottam, in Nottinghamshire, in March. That installation will help manage voltage stability following the decommissioning of Cottam Power Station.
At Wylfa, on Anglesey, the reactor came online in April and will support the North Wales network, including the Dinorwig to Pentir project. That scheme is replacing infrastructure originally installed in the 1970s, while also adding further capacity between Dinorwig and Pentir substation.
The final reactor, at Willington in Derbyshire, was energised in May and is being used to support the expansion of the substation.
The installations form part of National Grid’s wider programme of transmission network investment, with £31 billion planned over the next five years to modernise and upgrade its infrastructure.
Paul Gallagher, Operations Director at National Grid, commented, “Shunt Reactors may be a lesser-known part of our network, but they play a vital role in ensuring electricity supplies are stable and reliable.
“I would like to thank all of the teams involved in delivering this complex activity, which involves a considerable amount of planning and coordination, both on time and on budget.
“It is just one part of the wider work that we are doing to maintain and upgrade the network, ensuring it is resilient and fit for the future to support growing energy demands.”
