Value of Fast Switching Devices to Electric Distribution Networks : An Approach to Reduce Voltage Sags and Interruptions in Distribution Networks

Abstract: Power Quality (PQ) has gained a lot of importance in the last decade. Several solutions to power quality problems have been proposed and developed. With the advent of solid state technology and power electronics in the power system protection devices, faster switching is achievable. In order to control and minimize the power quality problems which occur in extremely short times of less than 100ms, the need arises for a selection of devices that can switch faster than today. Also, the economic losses that occur in the network due to the power quality problems increase the incentive to transform the existing devices into faster and e fficient devices. This transformation can be seen as valuable from both a technical and economical point of view to the distribution networks today where a large number of customers are connected. However, in order to interpret the value these fast switching devices render to the distribution network a prior study is required. This thesis presents a picture of the devices that can be suitable for fast switching in today’s distribution network, and how to determine their value to the distribution network. Further it summarizes the research work related to this field. The description of the devices and technical aspects is presented first. A literature review of proposed devices is given. The technical aspects of power quality and its problems is described. An approach to estimate the value of the fast switching devices is detailed from different literature. The study shows that fast switching devices can be worthy to invest in when seen from a distribution network’s perspective provided that different technical aspects are taken into account.