Adaptation of Load-Frequency-Control Target Values Based on the Covariances Between Area-Control Errors

This paper proposes a parametric, statistical model for adapting the load-frequency-control (LFC) target values that are used for a performance evaluation. These target values should be determined in such a way that the system frequency will be bounded within the target range. One way of bounding the system frequency is to bound the variations of the area-control error (ACE) by increasing the control activations. On the other hand, the frequency can also be bounded by mutual coordination of the control among the control areas, thus affecting the covariances between the ACEs. Existing models for determining the LFC target values do not consider the covariances between the ACEs. The proposed model incorporates, for each area individually, the estimated value of the covariances between the ACEs and is inherently frequency dependent. In this way, appropriate shares are obtained for the target ACE ranges among the control areas. The extensive field measurements in the discussed control area confirm the advantages of the proposed model over existing models for a monthly and online estimation of the LFC target values.