Loss Reduction and Voltage Stability Enhancement of Distribution Network through Optimal Allocation of Distribution STATCOM Case Study: (Axum Distribution Network)

Abstract

This thesis presents the way of improving the performance of the distribution network by improving the voltage profile and reduces the power loss by integrating D-STATCOM to Axum K4 distribution feeder. D-STATCOM is commonly used in the distribution system for reactive power compensation so that it improves voltage profile, reduces power losses and improves the system voltage stability. The study of this work was conducted on Axum distribution K4 feeder it consists of a total number of Fifty-nine–bus feeders, of which bus-1 is taken as a reference node or slack bus, the other 47 nodes are connected to loads through step-down distribution transformer, and the remaining 12 nodes are common coupling nodes. The voltage profiles of most buses are not in an acceptable range, and the voltage stability index of the buses shows that the network is prone to voltage stability problems. The active and reactive power loss of feeder is 131.72KW and 111.35KVAr respectively. The optimal D-STATCOM allocation in electric distribution system enhances maximizing energy utilization, feeder loss reduction, and voltage stability and profile improvement. To allocate power control variable in the best possible location and with proper size two solution methods are applied. As the first method, the weakest bus of the system was selected for the optimal placement of D-STATCOM using bus based voltage stability index analysis. In the second method, particle swarm optimization (PSO) was applied for selecting optimal placement and size of DSTATCOM. The PSO optimization algorithm formulates a problem by considering system loss reduction, enhancement of voltage profile and voltage stability index of the operated network. A direct load flow analysis also carried out for the purpose of total system loss and bus voltage magnitude determination before and after compensation with D-STATCOM. The optimal allocation problem was tested in different system case based on the number and size of D-STATCOM. By comparing the net cost of D-STATCOM in relation to total system loss reduction single D-STATCOM installation has a better system. After the installation of single D-STATCOM with an optimal allocation through the feeder. The voltage profile of the system improved between 0.95-1.05p.u. The voltage stability index of the operated network increases as compared with base case stability. The active and reactive power loss through the line reduced to 25.03% and 25.25% respectively