Improvement of voltage SAGS, harmonic distortion and low power factor at distribution system by using voltage source converter (VSC) and active filter

Abstract

For many years, power quality were not give a big issue to the power system, because it cause no effect on most of the loads connected to the distribution system. It happen because only motor and generator based system only operates at that time. When an induction motor is subjected to voltage sag, the motor still operates but with a lower output until the sag ends. It not harm the motor but only effect the performance of the motor. With the increasing use of sophisticated electronics based system, high efficiency variable speed drive, and power electronic controller, power quality has become an important agenda and it will cause increasing concern to utilities and customers. Nowadays, voltage sags is the most common type of power quality disturbance in the distribution system. Even though it happens only in the microseconds, but it can be caused huge impact on the electronic based system. Sometimes, when fault occurs in the electrical network the nearest network connected to the fault network will sense the voltage sags event. Although the electricity utilities and semiconductor or electronic based system companies have invested some substantial amount of investment to improve the reliability of the network but they still cannot control the external and internal factor that can causes the fault, such as lightning strike, third party digging, illegally excavation activity, wrongly operated during maintenance activity or protection relay malfunction and etc. Therefore, the important thing is to come out with the solution to prevent or mitigate the network during fault event that can cause voltage sags happen. There are many researchers have come out with many method to mitigate this power quality issues such as DVR, STATCOM, SVC and many more. However, this project presents the mitigation technique to improvement power quality problem which were voltage sags, harmonic distortion and low power factor by using Voltage Source Converter (VSC) in distribution system. The VSC injects a current into the system to mitigate the voltage sags. LCL Passive Filter was then added to VSC to improve harmonic distortion and low power factor. The simulations were performed using MATLAB SIMULINK version R2010b.