Study and mitigation of Rwandan grid blackout and instability. Case study Huye city

Abstract

Blackout is defined as total loss of electricity in a particular area for a certain period, a long duration of power loss cause negative impact on productivity ,safety and security of community. A radial distribution line in case of Huye is long and challenged because is connecting three districts neighbors of Huye,the distribution line pass in hill, forest, disturbance caused by trees fall on distribution line, lightening stroke, earth fault, drop voltage lead to power cutoff (outage) several time. The instability of this network in a distribution network lead to malfunction of the system and bunt of consumer’s equipment. The maintenance in a radial network is complicated and require a long time to fix the cause and repair. To reduce the blackout occurrence, the power planner can focus on the advance control of the power system to control and reduce the disturbance and additional power transmission line. However, it does not prevent unreachable to have no blackout. The reason why it is possible and necessary to implement measures that can minimize probability and scales of these outages. This dissertation proposes a solution of microgrid with PV solar and energy storage to mitigate the blackout in Huye city especially city center. A description of the work start in the assessment and analysis the cause of power outage and weakness of the power distribution network to reach the consumers. A microgrid present of islanding supply from the system installation is simulated in steady state to show the strength of system and reduce the blackout duration in Huye. The microgrid is designed, simulated and optimized for technical and financial feasibility in comparison with power grid using HOMER software. The microgrid composed with PV solar and energy storage is feasible for low price of electricity purchased 0.198$ compare to the price of grid power to 0.220$.