Load Flow Analysis of Transmission System With Integrated Radial Distribution Network by Connecting Solar DGs

This study presents a load‐flow assessment of the IEEE 9‐bus transmission system with an integrated 85‐bus radial distribution network (RDN), incorporating solar‐powered distributed generators (DGs) to enhance energy efficiency and grid stability. Load flow of the IEEE 9‐bus transmission system is accomplished using Newton–Raphson to determine voltage magnitudes, phase angles and power flows. Further, an 85‐bus RDN load of 3.64 MVA operating at a 0.8 power factor is placed at bus 7 of the IEEE 9‐bus transmission system. For this RDN, load flow is evaluated using the forward–backward sweep algorithm. The simulation results reveal that certain buses experience voltage deviations beyond acceptable limits. To tackle this, the multi‐objective slime mould algorithm (MOSMA) is applied to identify the optimal locations for solar DG placement. The integration of DGs at these optimised points helps reduce power losses, decrease dependency on conventional power sources and enhance the overall stability of the system. To further evaluate the robustness of the system, case studies were conducted under variable solar generation scenarios and transmission system load variations. These scenarios are considered to examine the ability of the integrated transmission–DN to sustain acceptable voltage limits and maintain operational stability under varying generation and loading conditions.