Effects of uncertainties in frequency regulations on probabilistic power flow analysis

Uncertainties in frequency regulations (FR) of generators and loads, and their effects on probabilistic power flow (PPF) analysis are addressed in this paper. The conventional PPF analysis is based on power flow model, without considering the frequency regulation. However, according to frequency regulation characteristics, generation outputs and load demand will respond to frequency deviation. Furthermore, since owners of generator units have strong economic motivations to prevent effective governing response as expected, and the load-frequency regulation coefficient of load varies with its components, the overall regulation coefficients of system cannot be completely determined and thus have some uncertainties. With some assumptions on the probabilistic distributions of regulation coefficients of generators and loads, a probabilistic power flow problem considering uncertainties in frequency regulation is presented and then solved by point estimate method (PEM). Simulations results from the IEEE-9 bus system and a 173-bus in real life with and without uncertainties in frequency regulation coefficients considered are presented and compared.