Simplifying Wide Area Coordination of Directional Time Overcurrent Relays Using Automatic Settings Selection

Relay coordination is an extremely difficult, yet vital part of a comprehensive protection strategy for modern power systems. Ensuring that relays in these coupled systems behave in a consistent, predictable manner is a time consuming process which traditionally requires substantial engineer effort with manual analysis of numerous combinations of settings values. Furthermore, there is typically no assurance at the end of the process that a near best solution was found. There is previous work in the literature towards automating this activity, but existing methods have yet to completely automate the workflow and expand it to use on real world power systems. In this paper, we present a framework for the automatic generation of coordinated relay settings for directional time overcurrent relays, which represents one of the most challenging coordination problems engineers face. Our framework extends existing approaches and increases the level of automation by seamlessly interacting with fault simulation software to both provide input to and verify the coordination results of pickup and time dial settings chosen by the setting generator. This advancement is accomplished by designing a general software infrastructure for parameter selection, integrated with techniques developed in our previous work for automated relay settings development [1] and NERC PRC-027-1 coordination [2]. Experimental results on several grids, including a real world example where we have previously created settings manually, are presented to demonstrate the speed and precision of the proposed approach.