Improving power supply quality is one of the most important tasks in electric power engineering today. As modern industrial equipment becomes more sensitive to power supply quality, the distortions in power supply systems such as voltage sags, voltage outage, voltage fluctuation and harmonics can cause a lot of production losses and subsequent monetary costs. On the other hand, the power supply quality can also get affected by faults, types of connected load and operations of the power system. This is unavoidable. In fact, there have been many solutions proposed to improve power supply quality. Based on a review of existing power quality devices, the research objective of this thesis is to develop a more flexible and faster power quality conditioner. Therefore, a device called a dynamic unified power quality conditioner (UPQC)is proposed to overcome aforementioned power quality problems. Master of Engineering