Variable Frequency Drives Based Fuzzy Logic to Assess Harmonic in Power Distribution Systems

Power systems may suffer from harmonic levels, so grid designers plan to control the generated harmonics due to load nonlinearity. Control studies are increasingly imperative in grids integrated with Renewable Energy Sources (RES), as the integration is aided by power electronic devices that cause harmonics. Due to the industrial and commercial expansion in the outskirts of Baghdad city in Iraq, the planned expansion includes an increase in nonlinear loads. Hence, the Ministry of Electricity (MOE) planned to develop the New-Mazarea grid by integrating it with a VFD-aided hybrid RES. This study investigates the control of harmonics by designing a Variable Frequency Drive (VFD) using fuzzy logic. The VFD is connected as a shunt frequency source inside the RES substation to the Common Coupling point (CCp), where the Total Harmonic Distortion (THD) is 8.251%. The study approved the effectiveness of Single-Tuned Filter (STF) as compared to C-Type Filter (CTF) and High Pass Filter (HPF), second order. The study clarifies the impact of choosing a suitable STF size of 2350 kVAr in reducing THD to 3.159%, which depicts the successful VFD fuzzy design in controlling harmonic impact to be within the standardized levels, enhancing the distribution power system quality, and improving the system voltage, solving the voltage drop issue.