VOLTAGE SAG MITIGATION USING A NEW DIRECT CONTROL IN D-STATCOM FOR DISTRIBUTION SYSTEMS

With the growth of need of electrical energy in the technological societies, the demand for receiving the high quality electrical energy is being increased. Among the different disturbances affecting the power quality, the voltage sag and temporary voltage are essential issues especially that need to be fully investigated in the automated systems. In this paper, firstly, the effects of voltage sag due to three phase short circuit, staring of induction motor and transformerenergizing are studied. Then, influence of voltage sag compensation by means of distribution synchronous compensator (D-Statcom) is investigated After that, a method, namely direct control is presented for this compensator. The method measures the active and reactive powers simultaneously to control directly the switching patterns in the D-Statcom. The proposed direct control system is capable to minimize the power interruption and voltage sag and it is independent of system parameters using direct control. The method is then simulated on an IEEE standard-test system using PSCAD/EMTC software. The results of the simulation shows the proposed method in control strategy is able to compensate voltage sag.