Optimal utilization, sizing, and steady-state performance comparison of multiconverter VSC-based FACTS controllers

This paper describes a method for optimal dimensioning of multiconverter voltage sourced converter-based FACTS controllers. This general method allows comparisons of the steady-state performance and effectiveness of all single-, two-, and three-converter controllers in achieving specific power system operating objectives. The controllers considered include the generalized unified power flow controller and its subdevices, i.e., the static compensator, the static synchronous series compensator, the unified power flow controller, and the interline power flow controller. The effects of various shunt and series converter size modularizations in multiconverter FACTS controllers are demonstrated. Sensitivities to power system topology related issues such as system strength, parallel paths, and compensated line impedances, as well as system loading, have been analyzed. An optimal power flow (OPF)-type formulation with embedded effective impedances and/or current injections is utilized to provide a single framework for representing all single- and multiconverter FACTS controllers considered. A small power system model is utilized in this study mainly focusing on the FACTS controller utilization and performance. Realistic constraints representing various converter limits have been implemented. MATLAB optimization routines are utilized.