Utilizing Demand Response in Load Modelling for Voltage and Reactive Power Control Studies

In modern power systems the generation and load composition are changing, and systems are moving towards their stability limits. In these systems more emphasis should be given to demand response (DR) related possibilities and alternatives when assessing network voltage and reactive power control management aspects. To perform adequate system studies and assess system performance it is of critical importance to model the system components in adequate manner. In this paper, load modelling aspects related to DR possibilities for voltage and reactive power control are discussed in detail. A reactive power-voltage (QV) analysis approach is proposed to determine the load's capability to provide voltage and reactive power support through DR during contingencies near nominal voltage levels. Different load modelling alternatives, i.e. static and dynamic load models, are covered together with detailed analysis on their influence and limitations regarding network voltage and reactive power control. It is shown that DR actions can be integrated into composite load models in a manner that enables the analysis of reactive power management and voltage control with existing network planning models. The results presented in this paper are relevant for network owners and system operators when deciding the needed level of details in their study models.