Modified group search optimisation‐based comparative performance evaluation of thyristor controlled series capacitor‐based fractional order damping controllers to improve load frequency control performance in restructured environment

Abstract

This study compares fractional order phase lead-lag controller, fractional order proportional-integral-derivative (FOPID), and tilt-integral-derivative controllers as thyristor controlled series capacitor (TCSC)-based damping controller to improve load frequency control (LFC) performance in a restructured power system. To prepare an efficient ancillary service, a precise formulation for participation of TCSC in tie-line power flow exchange is presented which is compared with the earlier Taylor-based approximated model. The controller parameters are adjusted by employing different evolutionary algorithms. To obtain realistic results under a competitive environment, a diverse-GENCOs multi-DISCOs power system with the generation rate constraint and governor dead-band effects, communication time delay, bilateral contracts, and pool-co transactions is taken into account. Non-linear time-domain simulations demonstrate that the FOPID-based TCSC damping controller in coordination with an integral-type simple LFC can most effectively suppress the area frequency and tie-line power oscillations. Further investigations are performed for uncontracted higher order step and random load demands treated as contract violation scenarios to confirm the superiority of the proposed fractional order controllers-based TCSC–LFC over the Taylor-based TCSC–LFC. The sensitivity analysis is done for a wide range of loading condition and system parameters to compare the robustness of the considered controllers.