Application of Minimum Spanning Tree algorithm for network reduction of distribution systems

This paper demonstrates the application of a graph search algorithm for the network reduction of the distribution feeder. The purpose behind the network-reduction is to develop a reduced distribution system to facilitate the dynamic analysis of the feeders with high penetration of PV generators. Dynamic analysis requires modeling of the distribution feeders in the electromagnetic transient programs for understanding the transients. Performing the transient analysis on large distribution feeders with high PV penetration is time intensive and impracticable. To aid this purpose a network-reduction algorithm for the distribution feeder is proposed in this paper. The objective is to develop a reduced distribution system to support the study of long-term transients of the PV inverters such as - interaction with other control devices (capacitor banks and PV generators), cloud transients, and voltage flicker. This paper proposes a novel network-reduction technique, based on a network-flow procedure, which is referred to as Minimum Spanning Tree (MST) with additional capabilities. The network reduction proposed in this paper selectively retains the laterals and additionally accommodates the reactive power generation from the cable capacitance to the loads. The proposed algorithm will serve as an interface for modeling the feeder from the GIS database to the transient analysis tool.