Comparison of Voltage Calculation Techniques for Varying Load Distribution in DG-Integrated Networks

摘要

Voltage profile of a network is ruled by the network attributes i.e. power flow, load distribution, conductor sizing inter alia. Distributed Generation (DG) impacts the voltage profile and this in turn will impact network devices. This paper explores two different techniques (Method A and Method B) of calculating a voltage profile. Each technique uses a different equation to calculate the change in voltage in a feeder. The techniques are subjected to simulations on a linear, uniformly distributed feeder with a constant R and X per unit length. The impedance of the network is altered to represent varying R and X per unit length along the distance of the feeder. Using a feeder with non-uniform network impedance, the load distribution is varied from a uniform load distribution to a non-uniform load distribution. Here extreme cases on non-uniformly distributed feeders were tested. The aim of the paper is to compare two methods of determining the voltage profile of an MV network with DG connected and quantify the voltage deviation between the calculated and actual voltage profile under varying network conditions. This will determine the accuracy of each method which may influence its application. All simulations were completed using DIgSILENT Powerfactory on a test feeder to verify the accuracy of both techniques (Method A and Method B). The voltage profiles are plotted, providing a visual representation, and the accuracy compared.