Measuring and analyzing the impact of voltage and capacitor control with high speed data acquisition [distribution system]

Experimental results on the effects of capacitor switching on feeder operating variables as measured in the substation by a high-speed data acquisition system are presented. Consistent with the modeling of feeder loads as constant power, the switching in of a capacitor bank to improve power factor results in decreased reactive power injection and increased phase voltage. However, a reduction in real power injection reflecting reduced line losses is not observable at the substation. Similarly, the switching out of a capacitor bank results in increased reactive power, decreased phase voltages, and decreased real power. Analysis of the experimental results, using voltage-sensitive load models shows that while feeder losses are reduced following feeder power factor correction, the attendant improvement in voltage profile results in an increase in load that exceeds the amount of loss reduction. Consequently, distribution system operators using supervisory control and data acquisition systems will not be able to observe the loss reduction associated with capacitor switching to improve power factor