DSA/WDO based PI controller tuning for D-STATCOM for reactive power compensation

Distribution static synchronous compensator (D-STACOM) has a greater importance in modern distribution level for reactive power compensation dynamically and power quality improvement. In this paper an effort has been given to design a D-STATCOM, an essential shunt Flexible AC Transmission Systems (FACTS) device using decoupled current control method for three phase three wire system to compensate the reactive power. It is difficult as well as time consuming process to get the proper tuning parameters of PI controller for D-STATCOM using conventional methods. An attempt has been made by implementing two recently developed global optimization techniques named Differential Search algorithm (DSA) and Wind Driven optimization (WDO) for proper tuning of parameters by minimizing the integral square error (ISE) for both outer voltage controller and inner current controller simultaneously. The PI gain calculated by DSA and WDO shows in terms of reduction of error, improvement of overshoot in capacitor voltage waveform, convergence speed and some other parameters of the circuit. Comparative study of both the methods with trial and error method reveals that DSA algorithm based PI controller tuning method gives more optimized results.