Improvement of Distribution Systems Affected by Voltage Drop at Load Bus Using Power Flow Estimation Methods

Abstract

This article presents the improvement of an electrical distribution system utilizing a 250kVA transformer that supplies power in a radial network configuration. The distribution system is modeled as a 6-bus system, with transmission line parameters determined based on conductor size, distance, and configuration. Power flow calculations are performed using the Gauss-Seidel method to estimate voltage and power losses in the power system (Case 1), identifying a voltage drop issue at Bus 4 is 199.68 V. To address this voltage drop, improvement method are proposed. In Case 2, the transformer is relocated to the load center network, resulting in an estimated voltage at Bus 4 is 207.03 V, a voltage increase is 3.68 % and a power loss reduction is 6.97 %. However, the voltage remains below the operational rated of 230 V. In Case 3, add a second transformer 50 kVA is installed at Bus 4, the voltage to the operational rated, with an estimated voltage increase is 15.18% and a power loss reduction is 24.93%. In Case 4, capacitors are introduced as an alternative to the 50kVA transformer, employing two sizes is 391 μF and 270 μF, while using the Power Loss Index (PLI) and Capacitor Suitability Index (CSI) to determine optimal installation locations, resulting estimated voltages at Bus 4 is 208.32 V and 206.55 V, corresponding to voltage increases is 4.33% and 3.44%, respectively. The capacitor-based approach further reduces power losses by 40.62% and 31.60%, respectively. The analysis results demonstrate that Case 2, while suitable for load distribution, is impractical due to the relocation costs and its inability to resolve the voltage drop issue. Case 3 improvement the voltage across the system and successfully mitigates the voltage drop at Bus 4 to meet the operational rated, making it appropriate for accommodating future load demands despite higher installation costs. Case 4 is effective for reducing power losses and improving power flow efficiency in systems where the voltage already meets the operational rated. This study provides guidance for planning improvements to the electrical distribution system, addressing voltage drop issues while enhancing power efficiency.