PURPOSE AND SCOPE

This document gives the separation distances from commercial wind turbines to be applied for overhead line circuits operating at nominal voltages of 275kV and above on the National Grid transmission system.

Commercial wind turbines produce significant turbulence in their wake, while conductors on overhead lines are susceptible to damage from vibration initiated by wind. This policy sets out measures to reduce the likelihood of premature wear on conductors and fittings which, if uncontrolled, may lead to a significant reduction in asset life, increased maintenance, unplanned outages or ultimately conductor failure. A reduction to the separation distance previously required has been made as a result of research work carried out by Manchester University on behalf of National Grid; this is recorded in TR(E) 453. Further research partly financed by Innovation Funding Incentive (IFI) is ongoing within the UK Electricity Supply Industry to further investigate the effects of wind turbine wake particularly on bundled conductors. Where the opportunity arises, field trials will be undertaken to monitor the performance of overhead lines adjacent to new wind turbines. Following the outcome of the longer term work, this Policy will be reviewed and updated if appropriate.