Maintaining long rural feeders with large interconnected distributed generation

In some states, regulated utilities are required to interconnect a generating renewable energy customer, and the customer is required to pay for infrastructure required to support the connectivity while preserving the power quality and reliability of the distribution system it is being connecting to. The host utility is responsible for performing studies to make the lowest cost improvements that accommodate the customer and maintain service quality. These studies and improvements are made with limited knowledge about the dynamic changes that will impact a rural distribution feeder in the future. The natural changes to a distribution feeder that follow in the years after the DG customer has been connected, can leave the host utility with a range of costly challenges to continue to provide the same level of service to all of its customers. This paper discusses a range of engineering challenges a host utility has confronted in its effort to maintain the quality of service to its customers in the years after in it interconnected a 9MW landfill generation customer several miles from the substation on a long rural 23 kV distribution feeder that serves over a thousand customers. While the engineering work and the additional infrastructure constructed to accommodate the DG customer was appropriate and cost effective at the time that the DG customer was interconnected, this long rural feeder has required constant review and creative adjustment to maintain service quality as the feeder continues to change. The ongoing challenges have impacted reliability, capacitor control, voltage regulation, flicker and automation.