Analyzing the Effect of Using Facts Devices “STATCOM and SVC” in a Network Including DG Resources in terms of Power Quality “Voltage Sag and Voltage Unbalance”

Abstract

Voltage unbalance and Voltage Sag is one of the main important reasons of energy loss in power networks and impose considerable economic loss on the electrical industry. On the other hand, considering the growing trend of using DGs, FACTS devices can be employed to decrease the voltage unbalance and improve the power quality. Power distribution firms are very concerned about power quality due to the increased awareness of users and growth of sensitive loads in power system. Decreasing the effective or maximum value of the voltage between 0.1-0.9 per unit at the main frequency for 0.5 cycle to 1 minute is defined as the Voltage Sag which is one of the power quality issues, introducing large loads like furnaces, driving large induction motors or line to ground fault (SLG) and moving load from one power source to another are the main factors which lead to Voltage Sag in a power system. Equipments like DVRs and parallel FACTS devices protect the system's loads against the Voltage Sag and voltage unbalance. Now, In this article we consider two types of FACTS devices and study their effects on improving power quality parameters "Voltage Sag and Voltage unbalance" in a typical network including DGs