A SOFTWARE TOOL FOR COORDINATION OF CONTROLLERS IN POWER-SYSTEMS

This paper reports the theoretical background and the methodology of development of a software tool for off-line coordination of power system controllers in either a high-frequency range (5-55Hz) or a low-frequency range (0.1-2.0 Hz). The controllers considered for coordination are: voltage regulators, power system stabilizers (PSSs), speed governors, main and auxiliary controllers of HVDC converters, and main and auxiliary controllers of static VAr compensators (SVCs). The software package calculates the eigenvalues associated with a pre-specified number of least stable oscillatory modes of the system using a modified version of die “S matrix method”, and adjusts the controller parameters to increase the damping of the least stable mode, using a gradient optimization technique. The software tool is referred to as EICO (Eigenvalue program for Coordination of controllers). EICO is coded in FORTRAN. The application of EICO is demonstrated by coordinating the controllers of a power system with 371 state variables and 140 controller parameters, in the high-frequency range. EICO results are verified by detailed digital simulation of the system, using the BPA's Electro Magnetic Transients Program (EMTP). The study results demonstrate the technical advantages of the coordinated controllers as compared with the non-coordinated scheme. © 1990 IEEE