Evaluation of protective schemes for grid-connected generator-transformer units in Egypt / Ahmed Abdelrahman Abdelfattah ; Supervised Mahmoud Ibrahim Gilany , Doaa Khalil Ibrahim

Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Electrical Power and Machines

Repeated breaks of generation power stations in last few years are recorded. Because of their great impact on the Egyptian unity network (500 kV and 220 kV), it is essential to deeply review the efficiency of various existing protection schemes designed for generating stations. Detailed analyses of some of the major and destructive real faults recorded at some stations are carried out. Accordingly, modifications for the power plant protection schemes are recommended. The main objective of this thesis is to suggest the necessary future work for further enhancement of the existing protective scheme. MATLAB/SIMULINK model is applied on a practical case study to investigate the various solutions for generator decrement characteristic. Two applied case studies are evaluated to show the effectiveness of the Generator Circuit Breaker for clearing the faults quickly and minimize the equipment damage. On the other hand, mechanical factors (Inertia constant, H, and Friction, F) are studied and the generator performance during fault condition is recorded at different values of H and F. Recommendations and future works are presented to minimize fault clearing time from generator decrement characteristics

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