Power Quality Improvement in a Utility Grid by using Proportional Resonance Controller Based D-STATCOM

Increasing awareness and concerns regarding unacceptable power quality are causing a growing interest in custom power devices, used to improve power quality on distribution level. One of the most interesting types of custom power devices, due to its exibility and fast control, is the shunt-connected voltage source converter (VSC), also known as the static synchronous compensator (STATCOM). A single distribution static compensator (DSTATCOM) connected at the beginning of the network working in current control mode is capable of circulating power. In this dissertation a comparative analysis has been made between the conventional proportional integral (PI) controller and proportional resonance (PR) controller. This voltage controller holds the voltage at the point of common coupling (PCC) and supplies/absorb necessary power to keep the system stability. The DSTATCOM is assumed with a battery to enable this facility. However, correcting the PCC voltage to 1 per-unit (pu) cause a large amount of reactive power to/from the utility substation. This increases the current flow in the system and increases the line loss where the R/X ratio is high. It is desired to have the least reactive power from the utility substation. A modified voltage magnitude controller can solve this problem though it changes the voltage of buses.