کنترل تولید خودکار سیستم هیدروترمال TCPS تحت سناریوی بازار آزاد: یک رویکرد منطق فازی

This paper presents the analysis of automatic generation control of a two-area interconnected thyristor controlled phase shifter based hydrothermal system in the continuous mode using fuzzy logic controller under open market scenario. Open transmission access and the evolving of more socialized companies for generation, transmission and distribution affects the formulation of AGC problem. So the traditional AGC two-area system is modified to take into account the effect of bilateral contracts on the dynamics. It is possible to stabilize the system frequency and tie-power oscillations by controlling the phase angle of TCPS which is expected to provide a new ancillary service for the future power systems. A control strategy using TCPS is proposed to provide active control of system frequency. Further dynamic responses for small perturbation considering fuzzy logic controller and PI controller (dual mode controller) have been observed and the superior performance of fuzzy logic controller has been reported analytically and also through simulation.

Large scale power systems are normally composed of control areas or regions representing coherent groups of generators. In a practically interconnected power system, the generation normally comprises of a mix of thermal, hydro, nuclear and gas power generation. However, owing to their high efficiency, nuclear plants are usually kept at base load close to their maximum output with no participation in the system automatic generation control (AGC). Gas power generation is ideal for meeting the varying load demand. Gas plants are used to meet peak demands only. Thus the natural choice for AGC falls on either thermal or hydro units. Literature survey shows that most of earlier works in the area of AGC pertain to interconnected thermal systems and relatively lesser attention has been devoted to the AGC of interconnected hydro-thermal system involving thermal and hydro subsystem of widely different characteristics. Kothari et al. [1] have investigated the AGC problem of a hydro-thermal system provided with integral type supplementary controllers. It is to be appreciated that in a realistic situation, the system works in the continuous mode whereas the controllers work in the discrete mode. Perhaps Nanda et al. [2] are the first to present comprehensive analysis of AGC of an interconnected hydrothermal system in continuous-discrete mode with classical controllers.

This paper has investigated the performance of fuzzy logic based controller on a two-area TCPS based hydrothermal system under open market scenario. The conventional design approach requires a deep understanding of the system, exact mathematical models, and precise numerical values whereas a basic feature of the fuzzy logic controller is that a process can be controlled with the slight knowledge of the system and the consequences of a control action. This work builds a fuzzy rule base with the use of the area control error and rate of change of the error. The simulation results show that the proposed fuzzy logic based controller yields improved control performance than the dual mode controller.