Reliability Analysis and the Volt/VAr Control for Smart Distribution Feeders

With ongoing smart grid activities, there are a number of active demonstration projects in different parts of the USA. In the northwest, a demonstration project is being implemented by Avista Utilities to improve the reliability and efficiency of the distribution system. This project includes automated management of the distribution system and bi-directional communication capabilities between the field devices and the control center. With the added communication capacity, the newly installed equipment coupled with the distribution automation system has the ability to enhance monitoring and control as well as the potential to decrease the overall power demand with improved reliability. This research explores the applications of the distribution automation system for the Volt-VAr Control (VVC) scheme and improved reliability. Voltage regulation over a distribution feeder serves the purpose of achieving a flat voltage profile and maintaining the permissible voltage (plus or minus 5% of rated voltage) for all customers. VAr control allows power factor correction in near real time. To plan Volt/VAr control and correctly predict the benefits, an accurate representation of the load models is essential. The benefits of VVC include reduction of losses, maintenance costs, operating costs, voltage variation, and increases in the power delivery capacity of existing equipment. Resulting analysis of the VVC control shows demand savings of 2–3% for every 2.5% voltage drop. Reliability analysis with newly installed switches and midline reclosers shows significant improvement in the estimated reliability indices including SAIFI, SAIDI, MAIFI, CAIDI, and ENS.