Evaluation of CES and DFIG unit in AGC of realistic multisource deregulated power system

This article discusses evaluation of dynamic contribution of wind turbine unit of doubly fed induction generators (DFIGs) type and capacitive energy storage (CES) in frequency regulation services in 2-area interconnected power system, having diverse thermal-hydro-gas (T-H-G) generating units in deregulated power environment. To obtain optimal dynamic responses of area's frequency oscillations following a small load perturbation, CES/DFIG units have been included in both control areas in coordination with thyristor controlled phase shifter (TCPS).The behavior of DFIGs to enhance dynamic performances of the proposed power system has been investigated by providing inertial support through modified inertial control scheme. The control scheme responds proportionally to frequency variations due to sudden load changes in the power system and uses wind turbine's kinetic energy to provide the inertial control support under several operational conditions. The gain parameters of the integral controller is obtained by using integral square error technique. The performance of the proposed system has been examined in different contract scenarios. Results show that the coordinated action of CES/DFIG units with TCPS unit provide optimal transient performance by arresting the initial dip in area frequencies as well as the power flow deviation in tie-line between the 2 areas. Further, analysis reveals that CES unit response is better and quicker than DFIG unit to damp the system oscillations.