Introduction: The development of the first registered Power Zone (RPZ) in GB. This involves the application of an active rating to a 132kV overhead line based on real time measurements of ambient temperature and wind speed.

Objectives: Active ratings calculations based on CIGRE 207 equations are carried out at our control centre as part of the RPZ load management scheme that will curtail generation in the event of the line rating becoming exceeded. In addition there are two innovative areas, which required further research and are being funded via the IFI mechanism:

• Risk assessments identified the requirement for a local autonomous overload protection scheme, which calculates the line rating from local parameters in the event of a loss of communications. This would enable a higher current rating to be maintained while preventing the line thermal rating from becoming exceeded

• As verification of the assumptions made in the derived ratings, sensors will be attached temporarily to the conductors at various critical positions on the overhead line

• The additional Phase will not start until after 2011 due to ongoing way leave issues. It is intended that this will identify the spatial and temporal requirements of alternative sources of dispersed weather data to enable Dynamic Ratings to be applied to any circuit within WPD.