Cost Effective Approach for Limiting Voltage Dip Severity on Radial Industrial Feeders in Uganda

The rise in industries utilizing automated control equipment for production efficiency is exposing utilities whose distribution systems are vulnerable to power quality disturbances such as voltage dips. Voltage dips are temporary reductions in supply voltage that cause sensitive industrial process devices to malfunction leading to outages and economic loss in factories. This exploratory research was based on the hypothesis that; if an optimal capacitor bank design is developed to ensure that the pre-disturbance voltage profile on a radial feeder is improved to stay within acceptable limits at all times, then the voltage dip severity can be cost effectively mitigated during the large disturbance events without the need to deploy the expensive fast-switching devices such as the Static VAR compensators. Hence, on the Uganda distribution network, the Wabigalo 33 kV industrial feeder being long and radial was used as case study to establish a cost effective approach for limiting voltage dip severity using an optimal capacitor bank design. The Tabu search algorithm in combination with the Loss Sensitivity Factor applied in the DIgSILENT software was used to ascertain the optimal capacitor bank design with its performance and cost compared with the Static VAR Compensator as the standard method. The study found that the initial investment cost of the optimal capacitor bank design for the Wabigalo feeder is 23.5% of the cost of the Static VAR Compensator and provides superior performance benefits in terms of improvement of the pre-disturbance voltage profile and limiting voltage dip severity determined by residual voltage magnitude and voltage dip propagation.