Mitigation of power quality problems in Songwe power distribution line using a static distribution compensator

James Mhame, National Service Cooperation sole, P.0.Box 1694 Dar es Salaam, TanzaniaFollow
Emmanuel Matee, Department of Electrical Engineering, University of Dar es Salaam, P.O. Box 35131 Dar es Salaam, Tanzania.Follow
Francis Mwasilu, Department of Electrical Engineering, University of Dar es Salaam, P. O. Box 35091, Dar es Salaam, TanzaniaFollow
Sophia D. Kigodi, Department of Electrical Engineering, University of Dar es Salaam, P.O. Box 35131 Dar es Salaam, Tanzania.Follow

Section

Mathematics and Computational Sciences

Abstract

The Songwe electrical distribution system is prone to severe voltage drops that lead to frequent power outages in long feeders, light flickering, and the multi-operation of equipment and other appliances. The voltage at the switching station averaged 27.6 kV, 28.21 kV, and 25.79 kV in the years 2023, 2022, and 2021, respectively. Additionally, the maximum was 32.2 kV, below the nominal voltage, and the feeder has a very low power factor, which drops to 0.6 during peak hours. Currently, TANESCO uses automatic voltage regulators connected to a distant location from the switching station to two feeders with critical voltage drop (Tunduma and Kamsamba feeders), leaving other feeders with no means of regulating voltage. The automatic voltage regulators (single-phase oil-immersed auto-transformers) that are currently used have various problems, such as limited response time as they are mechanically operated. Moreover, they are linear compensating devices and dissipate heat when high voltage variation exists between the input and the output. To address these challenges, this paper proposes a Distribution Static Synchronous Compensator (D-STATCOM) with a linear integral controller to provide dynamic reactive power compensation and voltage regulation. The D-STATCOM injects or absorbs reactive power according to system demand, thereby mitigating voltage variations and improving power quality. The system model and controller were developed in MATLAB/Simulink and evaluated under load and source voltage disturbances. Simulation results demonstrate that the proposed controller restores the bus voltage to the nominal 33 kV with a settling time of approximately 200 ms and zero steady-state error, improves the power factor from 0.6 to above 0.85 lagging, maintains the system frequency at 50 Hz with zero steady-state error, and limits the total harmonic distortion to 1.89%, well below the IEEE 519 recommended limit. These results confirm the effectiveness of the proposed D-STATCOM in enhancing voltage stability and overall power quality in the Songwe distribution network.

Recommended Citation

Mhame, James; Matee, Emmanuel; Mwasilu, Francis; and Kigodi, Sophia D. (2026) "Mitigation of power quality problems in Songwe power distribution line using a static distribution compensator," Tanzania Journal of Science: Vol. 52: Iss. 3, Article 15.
Available at:https://doi.org/10.65085/2507-7961.1093