Comprehensive transmission distance protection settings using an intelligent-based analysis of events and consequences

This paper introduces a new methodology for settings of transmission system distance protection based on an intelligent analysis of events and their consequences. The output of the proposed methodology is comprehensive distance relay settings which include not only the zone reaches and zone time delays, as in the existing approaches, but also the optimal impedance operating characteristics, the fault detection settings, and the required relay sensitivities in terms of voltage and current. The need for this methodology is the result of the increased complexity of interconnected power systems protected with a large number of relays with different relay technologies, such as electromechanical, static, and numerical as well as diversity in their operating algorithms. The relay settings are automatically updated after every major change in the state of the network topology. Since it is not possible to include all design details of the proposed system, sample design events and rules are given to illustrate the proposed methodology.