Identification of coherent areas using a power spectral density algorithm

Abstract

The identification of coherent areas is an important step to fortify the power system against the potential spread of cascading failures. This processing task helps to establish the preliminary strategies to implement online control methodologies that increase the power system reliability. In this regards, a methodology to identify coherent areas based on sliding power spectral density algorithm is presented in this paper. A coherency index is estimated from self- and cross-power spectral densities information in order to identify the coherent areas for a specific frequency related to an inter-area oscillation mode. In order to facilitate and automatize the process, an identification criterion based in the coherency index is proposed. This enables the proposed approach to be applied offline or online. In addition, the computation of the self-power spectral density using a sliding window opens the possibility to detect the onset of transient processes. Synthetic signals and two test power systems with different dynamic characteristics are used to evaluate the potential application in large systems.