Discrete mode power system stabilisers

Abstract

The paper presents a comprehensive approach for the design of discrete mode conventional power system stabilisers (PSS) considering a machine infinite bus system, using the ISE technique. Investigations reveal that the sampler and zero order hold (ZOH) need to be modelled for sampling frequencies less than 20 times the Nyquist frequency and that, beyond 20 times the Nyquist frequency, the sampler and ZOH may be neglected from the mathematical model. A comprehensive sensitivity analysis reveals that the discrete mode conventional PSS is quite robust and its nominal optimum parameters need not be reset following ±20% changes in inertia constant H, field open circuit time constant T' i0 , line reactance x e , AVR gain K A or loading P and Q from their nominal values.

A Fuzzy Logic Based Discrete Mode Power System Stabilizer

“…The power system under consideration is essentially the same as that studied by earlier researchers [2,3]. The system parameters and the operating conditions are the same as given in [2]. Various studies have been performed to investigate the effect of the proposed FPSS.…”

“…1(b). The symbols and notations are the same as those given in [2], [12]. The relations in the block diagram apply to a two-axis machine representation with a field circuit in the direct axis and without damper windings.…”

“…T 1 -T 4 are PSS time constants and K c is the PSS gain. For the system under consideration, the tuned parameters of the CPSS by ISE technique for system under consideration reported in [2] are chosen. These parameters are K c = 47.0, T w = 10, T 1 = T 3 = 0.35sec, T 2 = T 4 = 0.05 sec.…”

“…A conventional PSS comprises of a wash out circuit and a cascade of two phase lead networks. To design such a PSS, many strategies [1][2][3][4][5][6] have been proposed in the past that included techniques such as root locus, Bode plots, eigenvalue assignment, multivariable frequency domain techniques, optimal controller design, etc. Numerous applications of new techniques [7][8][9][10][11] based on expert system, neural network and rule based fuzzy logic for PSS designs have also been reported.…”

Optimization of Fuzzy Logic Controller for Supervisory Power System Stabilizers

“…Where, K I and K A are constants, T Q is the time constant to be compensated, while T 1 and T 2 are the time constants of the lead-lag compensating network. More details of the CPSS can be found in references [5,6]. The values of these parameters and the controller gains are given Appendix A.…”