Analysis of the Volt/VAr control scheme for smart distribution feeders

With ongoing smart grid activities, there are a number of active demonstration projects in different parts of USA. In the northwest, an ongoing demonstration project is conducted by Avista Utilities to improve the reliability and efficiency of the distribution system. This project includes automated management of distribution system and bi-directional communication capabilities between the devices in the field and the control center. With the added communication capacity, the newly installed equipment coupled with the distribution automation system has the ability of enhanced monitoring and control as well as the potential to decrease the overall power demand. This research explores one aspect of the smart grid in distribution automation called the Volt-VAr Control (VVC) scheme. 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) at the end-use customer. VAr control allows power factor correction in near real time. To accurately predict the benefits and plan Volt/VAr control, an accurate representation of the load models is essential. The benefits of VVC include reduction of losses, maintenance costs, operating costs, voltage variation, and increase 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.