μ-analysis and synthesis for the uncertainties in static load modeling

The majority of loads in stability analysis are modeled as static. Choice of load representation characteristics greatly influences stability study results, as well as conventional power system controller design. But it is very hard to identify the exact proportion of load composition. Such inaccuracy may result in poor or even degrading control influence. In this paper, we represent the static load as the composition of constant power, constant current, and constant impedance. We then formulate the load representation inaccuracy into structured uncertainty. Finally we employ the structured singular value (μ) analysis and synthesis, which is a newly developed robust control method, to design and analyze the robust controller for TCSC. This controller has low order and can work well under different static load modeling. This controller design scheme is practical in the sense that it can adapt to a wide range of system parameters without significant increase in complexity.