Certain investigations on the performance of series hybrid active power filter for power quality improvement using intelligent techniques

Abstract

The extensive use of non-linear loads such as adjustable speed drives, diode rectifiers, Thyristor controlled rectifiers, uninterruptible power supplies and consumer electronics injects the harmonics into the distribution system. These loads draw harmonic and reactive power components of current from the supply. The presence of harmonics produces undesirable effects to the system like equipment overheating, capacitor blowing, overheating of motors, motor vibration, low power factor and excessive neutral currents. Moreover, it causes harmful disturbance to other sensitive electronic devices, malfunctioning of relays and generate interference to communication systems. Voltage sag is the most important cause that disturbing the Power Quality (PQ) in a distribution system. These disturbances affect both the utilities and the consumers. Hence, the sensitive loads such as computers and microprocessors are most affected equipment. To eliminate these problems, traditionally Passive Filters (PFs) have been used. Conversely, the demerits of PFs are fixed compensation, large size, and occurrence of resonance with other elements connected to the system. The recent harmonic mitigation techniques are used for the reduction of harmonics and improve the PQ. In practice, most of the voltage harmonic problems are created due to voltage sag and voltage disturbance. Hence, in this thesis a Series Hybrid Active Power Filter (SHAPF) is proposed, to provide an effective solution for voltage related harmonics produced by the non-linear load connected in the distribution system. SHAPF is a combination of series active power filters and shunt PFs newline