Reliability evaluation of smart distribution grids

Abstract

The term "Smart Grid" generally refers to a power grid equipped with the advanced technologies dedicated for purposes such as reliability improvement, ease of control and management, integrating of distributed energy resources and electricity market operations. Improving the reliability of electric power delivered to the end users is one of the main targets of employing smart grid technologies. The smart grid investments targeted for reliability improvement can be directed toward the generation, transmission or distribution system level. However, radial operating status, aging infrastructures, poor design and operation practices and high exposure to environmental conditions have caused the electric power distribution systems to be addressed as the main contributor to the customer reliability problems. Therefore, developing a smart distribution grid can be an attractive reliability enhancement solution for the electric utilities. Whenever the targeted reliability enhancement solutions are limited to the simple conventional solutions, the available reliability assessment techniques can be easily used for purposes of the value-based reliability planning. However, the electric utilities face a challenge when the reliability enhancement solutions include sophisticated measures such as those of the smart grid technologies. Generally, the available reliability assessment approaches cannot be employed directly for such purposes. In this situation, it is necessary to develop a reliability evaluation approach for predicting the reliability performance of the electric power distribution systems when employing such sophisticated solutions. A novel approach is proposed and demonstrated in this thesis for reliability assessment of an electric power distribution system when employing the advanced reliability enhancement technologies. In the proposed reliability evaluation approach, the overall impacts of the targeted reliability enhancement solutions on the sustained interruptions, momentary interruptions and voltage sags experienced by the customers are taken into account. The results of various reliability case studies directed in this thesis show that employing a suitable set of the smart grid technologies in the functional zone of an electric power distribution system can virtually mitigate all the reliability indices. It is also possible to reduce the range of variation of the reliability indices among different customers. In addition, there is a possibility to reduce the burden on the utility repair crews.