Abstract:
The world is witnessing a transition from its present centralized generation paradigm to a future with increased share of distributed generation (DG). Integration of renewable energy sources (RES) based distributed generators is a solution to decrease reliance on depleting fossil fuel reserves, increase energy security and provide an environment friendly solution to growing power demand. Major technical issues associated with DG integration are the impact on voltage regulation, harmonics, protection co-ordination, reactive power management, predictability of power output with RES based DGs. With the increasing usage of sophisticated sensitive electronic equipment in industrial, residential and commercial sectors, it is important to protect them from any power quality disturbance to avoid equipment damage and malfunction leading to economic loss for the customer. According to Leonardo Energy statistics the financial losses due to poor power quality amount to total of 150 billion Euros annually in the EU-25. The objectives of this research are to focus on the voltage stability problem in power system with DG integration keeping the harmonic content within the limits. DVR being one of the most effective series compensation utility for voltage regulation is used to reduce the overall harmonic content and better Voltage stability in medium level distribution system. DQ0 and Fuzzy Logic controller (FLC) based DVR are used in the power system to compensate for power quality issues like voltage sags/swells of several types. The DQ0 based DVR could restore the voltage levels to more than 93 % of the reference voltage when the system is subjected to 30% voltage sags whereas the FLC based DVR compensated for more than 96% of the reference voltage. The Harmonic content injected by both DVRs in power system is less than 5% which is the standard requirement for grid integration. The obtained results prove that FLC based DVR is more effective in compensating voltage sags of balanced and unbalanced nature with less number of harmonics injected in the medium level voltage distribution network
