Small Signal Stability Enhancement of Power System by Modified GWO-Optimized UPFC-Based PI-Lead-Lag Controller

Abstract

A major decisive task in power system stability enhancement is optimal setting of damping controller parameters. This work proposes small signal stability enhancement of power system using UPFC-based optimal PI-lead-lag controller, whose parameters are optimized by modified Grey Wolf Optimizer technique. Lead-lag structure has been very much popular in UPFC damping controller design but in this work the efficacy of lead-lag controller has been improved by proportional–integral (PI) structure. The modified GWO technique proposed here has been compared with GWO-optimized lead-lag controller and PSO, DE-optimized PI-lead-lag controller to justify its supremacy. ITAE criterion is selected for minimization problem considering an increase in input mechanical power to generator. The system eigenvalues, speed and line power deviations subjected to disturbance in power system show that the proposed PI-lead-lag controller performs better than conventional lead-lag controller and is much better in comparison to other optimization techniques to tune the controller parameters for enhancing stability of power system.

Appendix

(All the data are in per unit unless mentioned except constants)

Single-machine infinite bus test system data

$$ \begin{array}{*{20}l} {{\mathrm{C}}_{\mathrm{dc}} = 1,\, {\mathrm{H}} = 4{\mathrm{MJ}}/{\mathrm{MVA}}, {\mathrm{Ka}} = 100,\,{\mathrm{Ta}} = 0.01,\,{\mathrm{T}}_{\mathrm{d0}} = 5.044\,{s},\,{\mathrm{D}} = 0, \,\updelta_{0} = 47.13^{0},\,{\mathrm{V}}_{\mathrm{b}} = 1, \, } \hfill \\ {{\mathrm{V}}_{\mathrm{dc}} = 2,\,{\mathrm{V}}_{\mathrm{t}} = 1,\,{\mathrm{X}}_{\mathrm{B}} = {\mathrm{X}}_{\mathrm{E}} = 0.1,\,{\mathrm{X}}_{\mathrm{BV}} = 0.3,\,{\mathrm{X}}_{\mathrm{d}} = 1,\,{\mathrm{X}}_{\mathrm{E}} = 0.1,\,{\mathrm{X}}_{\mathrm{d}}^{{\prime }} = 0.3,\,{\mathrm{X}}_{\mathrm{q}} = 0.6,\,{\mathrm{Xe}} = 0.5} \hfill \\ \end{array} $$