The propagation of disturbances in power distribution systems

The propagation of power quality disturbances in distribution systems is investigated in this paper. Simulations of disturbances are accomplished using mathematical and PSpice modeling. Disturbances instrumented in the field are compared with PSpice calculations. Each component in the distribution system is modeled in detail using all available information. Measurements are used to refine the simulations, and having obtained a validated simulation, studies are made as to the effects of system components on the severity of power quality disturbances. The effects of disturbances on the system components, such as transformers, distribution lines and load models, are analyzed. It is shown that when disturbances propagate through a delta/wye transformer, many indices, such as unbalance factor, voltage regulation, and zero sequence levels, decrease.