Iterative simulation for protective relays closed loop testing using EMTP-ATP and CM Engine

Abstract

This work presents the development of an open source tool to conduct iterative closed-loop tests for protective relays using EMTP-ATP and Omicron's CM Engine. The advantage of this approach instead simple injection is that it is possible to interact with the electrical system by means of relay-controlled breaker operations allowing the testing of complex functions such as autorecloser. This tool was programmed in C++ and uses the powerful of EMTP-ATP to model and simulate flexible and dynamic scenarios; and CM Engine as interface to control the Omicron tester. This tool reads the .PL4 file generated by EMTP-ATP simulation, load the corresponding values to the selected channels into the tester that finally generate the voltage and current to be injected into the relay under test and receives the trip and close signals from the relay. This procedure is conducted iterativelly until the relay under test does not have reactions. Initially tests are conducted to compare the protective relay behavior to the proposed tool with the protective relay behavior to the same electrical system executed by a real-time simulator. Additionally tests with a large electrical system show the powerful of the proposed tool. The results show that this approach allow to conduct tests that have equivalent response as it was conducted by a real-time simulator.