Damping Controller Analysis

Simultaneous tuning of a PSS and SVC based damping controllers employing
NSGA-II for Power system stability problem

Narendra Kumar Yegireddya Sidhartha Pandab
Electrical Engineering VSSUT,Burla Odisha,India [e-mail], panda_sidhartha@rediffmail,comb

Ramakishore Bonthuc
Acharyulu B.V.Sd
Electrical & Electronics Engineering
LIET,Vizianagaram
Andhrapradesh,India [e-mail], [e-mail]

Abstract-In recent years power system stability problem is playing a vital role in the research technologies. Improvement of power-system stability by simultaneous tuning of power system stabilizer (PSS) and a static var compensator (SVC) based damping controller is properly investigated in this

3 is considered in this study as a SVC-based damping controller, Fig. 4 shows the structure of the power system stabilizer. The structure of SVC controller consists of a delay block, a gain block with gain KS, a signal washout block and two-stage phase compensation block. The signal washout block serves as a high-pass filter, with the time constant TW, the value of TW is not critical and may be in the range of 1 to 20 seconds [1]. The phase compensation blocks (time constants T1S, T2S and T3S, T4S) provide the appropriate phase-lead characteristics to compensate for the phase lag between input and the output signals. In Fig. 3, Vref represents the reference voltage as desired by the steady

The phase compensation blocks (time constants T1P, T2P and T3P, T4P) provide the appropriate phase-lead characteristics to compensate for the phase lag between input and the output signals.
b) Problem formulation
The washout time constants are usually pre-specified in the lead-lag structured type controllers, [1]. The t time constant of wash out block, TW = TWP =10s is preferred in the present paper. The controller gains of lead-lag block are KS and KPS and the time constants T1S, T2S, T3S , T4S and T1P,T2P ,T3P and T4P are to be determined. To improve the power system stability it is worth mentioning that the proposed controllers are designed to minimize the power system oscillations after a large disturbance.
In the present study, an integral time absolute error (ITAE) of the speed deviations and terminal voltages are taken as the objective functions J1 and J2 are respectively expressed as: (1) (2)
Where, Δω represents the speed deviation , ΔVb represents the change in voltage and tsim represents the time range of the