Measurement of the load frequency control system service: comparison between American and European indicators

This paper addresses the issue of measuring load frequency control (LFC) service by performing a state of the art in the field of indicators. The objective of the latter is to assess the way an interconnected control area contributes to support frequency according to its service obligation. Three indicators have already been designed. The first one, so called control performance standards (CPS), is now implemented in North America. Two other indicators have been designed in Europe following different approaches. For the first time, a comparison is drawn contributing to enrich the understanding and interpretation of indicator results. It is shown that European indicators can be considered as belonging to the same family as the American one, European indicators and the American one are respectively the expression of zero, first and second moment of the frequency error term. These three indicators provides fully guidance to ensure the quality of the interconnection frequency. In a particular operating condition, the CPS inherits some properties and does not fulfill the objective of establishing the responsibility of an incorrect LFC behavior.