Tracing the contribution from each generator to loads and transmission loss in a large power system using superposition principle

Abstract

In this research a new method is proposed for tracing the individual contribution from each generator to each line’s flow, each line’s loss and each load which is very much essential for billing the individual entities and for the control of a system in a deregulated or restructured power system. The conventional load flow alone cannot trace the contributions on such individual basis. In the proposed method all the generators have been modeled as current sources in terms of their total injected currents which can be determined using the system admittance matrix and the voltage solutions from a base case (i.e. all the generators acting together) conventional load flow. Then voltages at all buses only due to a generator acting alone (while other generators are considered ‘removed’ from the network) are obtained by multiplying its injected current with an augmented bus impedance matrix which is formed including the loads after converting them into admittances. Using these partial voltages the current flowing only from that ‘lone’ generator to each load and line are determined which in their turn are multiplied by the corresponding base case bus voltages to express the contributions in terms of power. The proposed method has been applied on the IEEE 24 bus Reliability Test System and a real life system (Bangladesh Power System). Its performance and validity are verified by comparing the sum of the individual contributions with the corresponding quantities obtained on total basis from the base case load flow of the network.