Centralised and Individual Shunt Active Power Filters in Radial Electrical Systems

Nonlinear loads in a radial electrical system generate harmonic components that distort supply current at the Point of Common Coupling (PCC). As a result, any linear load connected to the same PCC will operate under the distorted current condition. The radial system can install a Shunt Active Power Factor (SAPF) to mitigate the harmonic components. This work focuses on the centralised and individual SAPFs implementation to the supply current and linear load current waveforms in the radial system. There are three models of single-phase radial systems with a mixture of linear and nonlinear loads. An inductive linear load will be connected at the upstream, middle-stream or downstream of the radial systems. A single-phase SAPF based on Voltage Source Inverter (VSI) topology will act as centralised and individual SAPF depending on its connection points. A most straightforward control system consists of current and voltage control algorithms regulating the SAPF operation. According to the simulation findings, the centralised and individual SAPFs can mitigate harmonic components successfully. Regardless of the linear load's location, both filters maintain their performance in reducing the Total Harmonic Distortion (THD) of the supply current below 5%. However, they show different effects on the linear load current waveform. In conclusion, the centralised and individual SAPFs in the radial electrical system have different pros and cons.