الفهرس 
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Abstract
In this thesis, a new strategy is developed to deal with the recloser-fuse coordination problem without doing major changes in the working protection scheme. This problem arises from the integration of distributed generation in distribution systems. The main core of this strategy is based initially on an assessment process using a developed classifier. This classifier will classify the recloser-fuse coordination status at fault conditions to either coordination holds or coordination lost. Accordingly, the distribution system operator can take the proper decision. Then different actions are recommended as a solution to decrease the cases where coordination is lost and to partially solve the coordination problem.
The classification process is based on checking the operating sequence of all protection devices in the path from the faulted node to the substation node with the presence of distributed generation. Then this sequence is compared with a pre-required sequence obtained from the protection coordination philosophy. If a close match between the obtained sequence and the required sequence occurs, then coordination holds and no further action is required. Otherwise coordination is lost and a solution is required to avoid the consequences of miscoordination between protection devices.
To decrease the cases where coordination is lost, two actions are proposed. The first one is based on searching for the best location at which DG can be connected from the coordination problem point of view. The best DG location considered is that one with the highest number of cases classified as coordination holds. The second one is based on changing the fast mode recloser characteristics by changing the time dial parameter in the equation describing the recloser
characteristics. In case of the presence of multiple DGs in the system, another solution is also proposed and integrated with the previous two actions to enhance the protection coordination behavior. This solution is based on an offline study to prepare information about which DG that when disconnected the protection coordination can be re-attained.
The proposed strategy implies the following main tasks; load flow analysis, fault analysis, protection coordination setting, protection coordination assessment and protection coordination enhancement by applying the proposed solutions.
The main advantages of the proposed strategy is that, applying the classification process will discriminate between the cases where an action is required against the distributed generation penetration at fault conditions, and the cases where no need for an action is required. By this way, disciplinary actions like disconnection of distributed generation each time a fault takes place can be avoided, and consequently, the system reliability will be improved. On the other hand, applying the proposed solutions leads to reduce significantly the number of cases where coordination is lost and avoids doing major changes in the working protection scheme.
The proposed strategy is evaluated by being implemented to the IEEE 37-node test feeder and the IEEE 34-node test feeder; the obtained results are presented and discussed. All the required software is developed using MATLAB m-files as a platform.