Effects of series impedance on power system load dynamics

This paper analyzes the effects of series impedance, existing between an observation point and a load, on the active and reactive power dynamics of power system loads. First, the changes of dynamics expressed in the form of transfer functions are provided as the effects of series impedance, Next, a simulation shows that the change is small enough to allow approximation of the transfer function at the original order. The result also explains the empirical fact that the dynamics of most aggregated loads can be modeled by first-order transfer functions to obtain a good approximation, even though the order becomes higher as the effects of series impedance, insofar as the dominant load components are well approximated at the first order.