الفهرس 
Problem Solution Algorithm
Contingency Based Power System Security 3.1 GeneralOnly 14 pages are availabe for public view
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Abstract
A contingency in the electric power system is termed as a disturbance resulting from single or multiple equipment outages. This disturbance is a sudden change in the system configuration causing severe violations on the operating constraints such as branch overloads and bus voltage limits violation. These violations may result in successive interruptions leading to the occurrence of a partial or a total blackout phenomenon. This means that the resulting effects of contingency cases are investigated on the operating constraints of the system to prevent the occurrence of this phenomenon and hence to maintain the power system security that aims to keep the system operation in normal condition and especially in the event of a contingency.
The purpose of this thesis is to study the effect of power system component outages in terms of their severity on the system operating constraints to select and rank all severe contingencies, and then to apply the Remedial Action Schemes (RASs) that are necessary to withstand these contingencies and return the system into a secure state.
The N-1 Contingency Analysis (CA) technique using Newton Raphson Load Flow (NRLF) method in a DIGSILENT Power Factory environment is applied for each outage to investigate the resulting effects on the operating constraints of the remaining system. This thesis uses a hybrid of contingency screening method and the contingency Performance Index (PI) ranking method to select and rank all severe contingencies.
The contingency screening method is used to reduce the numerous calculations by eliminating the outages having no effect on the system operating constraints and selecting only the contingencies those lead to violations on the operating constraints.
All severe contingencies are ranked based on the Overall Performance Index (OPI) of test systems, considering Voltage Performance Index (〖PI〗_V) and Active Power Performance Index (〖PI〗_P) for each severe contingency case in MATLAB environment.
The Remedial Action Scheme (RAS) approach is applied to mitigate and remedy all severe contingencies in order to get the system back to its normal operation. In this thesis, Remedial Action Scheme -1 (RAS-1) and Remedial Action Scheme-2 (RAS-2) approaches are proposed. The RAS-1 approach is applied to correct both of branches overloads and bus voltage margin’s violations. The RAS-2 approach is applied to remove the probably load shedding in the RAS-1 approach and hence, to enhance the system reliability in post contingency cases. Load flow assessment is performed for each corrected system to validate the perfect effectiveness of RAS-1 and RAS-2 on the operating constraints.
This thesis underlines the necessity of considering RAS-1 and RAS-2 in all severe contingencies to reach a final test system configuration which successfully recovers from any kind of N-1 severe contingencies for getting a secure proper operation.
Reliability assessment is performed to examine the effect of equipment unavailability on the system reliability. Also, the most economical remedial scheme from the proposed RAS-1 and RAS-2 is discriminated to be used as a certificated remedial action from the economic point of view in the N-1 contingency criterion.
The N-1-1 CA is performed on the corrected system of the most severe contingency case to investigate the technical robustness of its certificated remedial action from the economic point of view.
This proposed work is implemented on the IEEE 5 bus system, IEEE 9 bus system, IEEE 14 bus system and IEEE 39 bus system in DIgSILENT Power Factory environment.