Estimating Frequency Changes Due to Smart Grid Functions

This paper presents a new approach for estimating the frequency changes (Df) due to the application of smart grid functions. The proposed approach is based on constructing a ZIP model to represent the power demands at certain point-of-supply, which feeds loads subject to smart grid functions. The constructed ZIP model provides a relationship between the active and reactive power demands and the frequency at that point-of-supply. Such a relationship can be formulated as a set of nonlinear equations that can be numerically solved for Df. The load-model based approach is implemented for performance evaluation using the IEEE 30 bus power system. Performance results show that the proposed approach has a simple implementation, and can provide an accurate estimation of frequency changes over long time intervals. Furthermore, the load-model approach is found capable of maintaining its accuracy without being affected by load demands, power ratings, and/or duration of demand changes.