Steady-State Fault Analysis of Unbalanced Power Distribution Network Utilizing a Novel Sequence Component Based Methodology

Classical sequence component-based fault analysis works well while computing fault currents for Transmission networks as the transmission circuits are transposed and the network is balanced. However, distribution networks consist of 1-phase and 2-phase lines, unbalanced lines and load, voltage control devices, multi-phase laterals, and different transformer connections. This breaches the basic assumption for the use of the classical sequence component method for fault computations in unbalanced systems with the existence of mutual coupling effect. In this paper, a novel sequence component-based fault computation algorithm for unbalanced power distribution systems is proposed in order to compute the fault currents during the single-line-to-ground fault, and three-phase-ground fault. The algorithm's accuracy and effectiveness have been validated on the IEEE 4 bus and 13 bus feeders. From the test results, it has been shown that the proposed sequence-based approach is accurate, robust and can be applied to real-life distribution networks when compared to the state-of-the-art sequence-based fault analysis.