Voltage Stability Improvement by Inclusion of Parallel Transmission Lines: A Case Study of Western Kenya Region

An integrated power system should provide stable and reliable power supply in any given economy. Western Kenya Region (WKR) has experienced voltage instabilities caused by inadequate transmission line infrastructure. The remedy adopted by Kenya Power is Under Voltage Load Shedding This paper proposes inclusion of parallel transmission lines to lower overall impedance and improve voltage stability and power transfer capability. The region's transmission system was modelled on an IEEE 39 Bus System and simulated using Digsilent Powerfactory software. The results revealed that parallel inclusion of transmission network significantly improved voltage levels and reduced loading of the main transmission lines into the region. The minimum bus voltage improved by up to 6.2%, whereas power transfer capability improved by an average of 42.09%. A Benefit/Cost Analysis qualified implementation of the proposed project to be economically viable. Due to increased loading on transmission lines, addition of Capacitor banks or suitable Flexible Alternating Current Transmission System devices at the buses with the lowest voltages would be recommended.