Browsing by Author "Mengistu, Addis"

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    Prevention of Blackout Using an Automated SCADA System in Case of EEP
    (Addis Ababa University, 2017-01) Mengistu, Addis; Dereje, Shiferaw (PhD)
    Nowadays the stability, reliability, sustainability and security of power system are the main concerning issues in Ethiopia because of frequently happening disturbances which will lead to total or partial power system blackout. When disturbances occur in power grid, monitoring and controlling of a power system are required to stop the grid degradation, restore it to a normal state, and hence minimize the effects of disturbances. However, in wide area power grid resulting from large and complex interconnection of power system network, classical systems based on manual operation and decisions are not able to rapidly respond for disturbances, which may cause a local or complete system collapse. Therefore the introduction of automated SCADA system with advanced measurement and very fast communication technologies provide better ways to detect rapidly the disturbances and protect the overall grid from the propagation of the fast cascading outages. Automation system improve the performance by taking advantage of faster computer control instead of human reaction times and also used to increase the efficiency of control by trading off high personnel costs for low computer system costs. This thesis presents the design of an automated SCADA system that can prevent the grid system from blackout in real time through active and reactive power balancing. Active power and reactive power of the system are the most essential parameters in the monitoring, control, and protection of power systems and electric equipments because when a fault or a significant disturbance occurs in a power system, the frequency and voltage varies in time and space. A modeling of electrical system elements was developed to have a complete one line diagram of the existing network using DIgSILENT power factory software version 15.1. The study has employed conventional power flow and dynamic analysis for assessing the stability and reliability of the system. Different type of faults has been used for the analysis, which leads the system to cascade outage. Finally, to mitigate these problems, necessary control measures have been presented. The result shows that whatever any disturbance experienced to grid has been controlled automatically without operator intervention and lead to normal operation condition. From the test results, the proposed technique presents better controlling method in comparison with that of the existing manual based control system in black out mitigation along with improvement in stability of the system. The method is implemented on the whole EEP grid and tested on specifically for northern and north western region.