Impacts of Distributed Energy Resources and Load Models on Conservation Voltage Reduction

Several studies and field tests have shown the potential of conservation voltage reduction (CVR) to decrease peak demand, energy consumption, and system losses. Nonetheless, the energy savings achievable by CVR is dependent on the load model, which could be constant power, current, impedance, or any combination of these models. Also, the use of distributed energy resources (DERs) at the distribution level presents a challenge to successful CVR implementation as these resources could cause voltage fluctuations in the system. This paper studies the impact of load models on CVR implementation in a distribution system feeder interfaced with renewable DERs. Load flow analyses are carried out using constant power (PQ) and constant impedance (Z) load models, respectively, and the resulting effects on feeder losses and energy consumption are observed as CVR is implemented. In addition, the impacts of DERs and voltage regulation devices on the feeder voltage profile are analyzed. The feeder losses showed opposite trends with constant PQ and Z loads as CVR is implemented. Overall, the results showed varied impacts of load models and DER output on feeder losses, energy consumption, and bus voltages in the distribution network.