Minimizing power systems distribution losses using direct load control

A recent study indicates that up to 13% of the total power generation is wasted in the form of losses in the distribution system. Network reconfiguration, capacitor installation, and reconductering have been used to reduce these losses. A new approach using Direct Load Control (DLC) of residential electric water heaters is proposed in this dissertation to minimize distribution system losses. When the power supply to water heaters is disconnected, the load drop per water heater equals its diversified demand at the time of load shed. When the interrupted loads are turned back on, the payback demand could be several times greater than the amount shed. One possible way to eliminate the detrimental effects of payback demand is to increase the storage capacity of the water heaters under DLC by adding a second water heater to an existing one or by, installing a single tank with sufficiently large volume. These additional storage devices are turned on during low load hours only and they store enough hot water to last during peak loads when the primary water heaters are disconnected.; An optimization algorithm based on the Lagrange Multiplier method has been developed to minimize the power systems distribution losses and their associated costs. The objective function is given in terms of the peak power loss cost, annual energy loss cost, and the cost of the DLC program. The objective function is solved to obtain the optimal number and location of water heaters under DLC.; The proposed methodology has been tested using two distribution system main feeders: a typical main feeder and a high loss feeder. The feeders were tested with and without laterals. Results show that the peak power loss has been reduced by 25.26% and 25.95% in the typical main feeder and by 27.34% and 28.17% in the high loss feeder. The annual energy loss was reduced by 1.94% and 1.96% in the typical feeder and by 2.20% and 2.26% in the high loss feeder. The feeders annual cost were reduced moderately (3.85% to 7.08%). The proposed methodology has also improved the losses and the generation costs in the transmission system.