Forecast ratio and security analysis of rating forecasting methods in an overhead line

The actual line rating in overhead lines varies with weather conditions. When a utility defines a rating value for the operation of the line, it takes into account both the security and the forecast ratio. The defined rating is secure if it is below the actual rating. A good rating forecast ratio is obtained when the defined rating is close to the actual rating. Therefore, the aim of a line rating forecasting method is to define a rating value that is close but below the actual value. This study shows the rating measurements carried out in a pilot overhead line and analyses the performance of several line rating forecasting methods comparing the defined values with the actual ones.