Correlation of High Harmonic Distortion to Shunt Active Power Filter Operation and Performance

Nonlinear load proliferation in power systems distorts the grid supply current and increases the Total Harmonic Distortion (THD) value. Therefore, this research investigates harmonic components produced by capacitive and inductive nonlinear loads. Next, it focuses on the effect of those harmonic components in selecting a single-phase Shunt Active Power Filter's (SAPF) DC-link voltage. Later, it assesses the filter performance using two DC-link voltage control algorithms tuned under two different operating conditions. In this research, the resistive value of both nonlinear loads is adjusted to ensure the load currents consist of the same fundamental component. Initially, a DC source is connected in parallel with the DC-link capacitor to remove the need for a Voltage Control Algorithm (VCA). Later, the VCA is tuned under two operating conditions when the DC source is removed from the filter. The simulation results verify that the load current of the capacitive nonlinear load has a higher THD value than the inductive nonlinear load; there is a significant difference in the amplitude of the harmonic components at low frequencies. Furthermore, the findings show that the SAPF requires a higher DC-link voltage when compensating for current with a higher THD value. It also verifies that VCA should be tuned under extreme harmonic distortion to enhance the SAPF versatility. All results demonstrate that nonlinear loads significantly affect the SAPF operation and performance.