Energy rating of overhead power lines OCC has been providing software to National Grid since 1999.

OCC has built up expertise in modelling the capability of critical components in the National Grid network to take electrical load. Typically these components are transformers or buried cables – quite different from the overhead lines the public associates with National Grid. The most common factor limiting how much power can pass through a circuit is the heat generated and the maximum permissible load is called the rating.

OCC has already delivered applications for determining ratings for transformers (TRALC2) and buried cables (GLOIN). Today, these models are integrated in the National Control Room to monitor every circuit on the grid and warn if any circuit is reaching its limit.

Following on from this work, National Grid contracted OCC to develop a ratings application for overhead lines.

The OHLRating project

The requirement was for a light client–server application compatible with the National Grid corporate desktop and the local network. Keeping the application architecture simple was a priority.

OCC verified and reimplemented an existing numerical model for calculating thermal ratings of overhead lines based on their construction, environmental conditions and current loads. The project also established a common database of overhead line engineering and rating data and provided functionality to export this data to the National Grid Critical Unit Programme.

The OHLRating project has delivered enhanced overhead line ratings and improved integration with Asset Management’s other functions.