Alleviation of Voltage Sag Using D-STATCOM

Quality of power is very important in current scenario. The widespread use of electronic equipment led to a change in nature of electric loads. These loads are simultaneously the major cause and the major victim of power quality problems.

Development of power electronics proposed several solutions to compensate for the fluctuations observed on the distribution networks, hence to ensure highest possible power quality to the consumers. These are called Power Quality Devices (PQ Devices). They are power electronic converters connected in parallel or in series with the lines and the operation is controlled using various controllers. Conventional among them is capacitor banks and filters, and was updated by SVC (Static Var Compensators) and then by STATCOM’s (Static Compensators). The STATCOM has several advantages when compared to “conventional” Static Var Compensator (SVC) using thyristors such as faster operation, reactive power production at low voltage, does not require Thyristor-Controlled Reactors (TCR) or Thyristor Switched Capacitors (TSC) and does not produce low order harmonics. Distribution STATCOM (D-STATCOM), is the most efficient and effective modern custom power device used in power distribution networks. D-STATCOM injects proportionate current in to the system to correct the voltage sag and swell.

 In this work, simulation and study of D-STATCOM used for alleviating voltage sag on a distribution network is carried out. Voltage sag will be simulated by the application of a sudden load in the existing feeder. The sag so generated will be corrected using the modeled D-STATCOM and the operation can be verified by testing it for different loads.