Power system protection relay testing : optimization of decoupling and overcurrent relay testing routines and preparation of an underfrequency relay test bench

Details

Supervisors

De Jaeger, Emmanuel

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électromécanicien

Abstract

The origin of this assignment is to be found in the desire to work on an extensive mission, covering the entire engineering process, from topic research through the design of a solution and its application. The task was defined in collaboration with an industrial partner, namely Laborelec, in the field of protection system testing. Through two assignments, the subject of protection systems and their testing is used to gain insights on the global engineering process. The first project covers the optimization of existing testing routines used by the company to qualify decoupling and overcurrent relays. The routines were initially copied from one relay to another and their parameters manually edited by the tester. This process could take up to over two and a half hours. The second project details the creation of new test files for the future testing of underfrequency relays. The test specifications were given by a client. All the tasks were carried out on an industry function based acceptance testing solution. It comprised a software package to implement the tests and to command a hardware test-set used to generate the electrical quantities injected in the relays. Available relays of each type were used to validate the test files. The first project resulted in the creation of two testing templates. The optimization of the routines is to be found in the automation of parameter updating. Custom test objects with parameters representing the tested devices and the performed tests were implemented in the routines. The parameters of the different test modules were linked to the values contained in the test objects. All these values are linked to a basic set of parameters corresponding to the relay settings. To reflect a change in the relay settings from one test to another, only the basic parameters need to be edited for the entire template to be updated automatically. This is done in just a few minutes. Besides its primary goal, this assignment also served as an exploratory assignment to apprehend the used tools. The initial methodology was rather rough and the templates required many edits before reaching the final versions. Upon completion of the first assignment, a rigorous test design methodology applied to the used testing solution had seen the light of day. The essentials are: (1) analyzing the hardware requirements, relay connections and settings, (2) programming the hardware configuration and the basic test object, (3) analyzing the tests to choose the right type of test module and parametrization for each of them, (4) implementing the different test modules and customized test objects, and (5) validating the tests and adapting when needed. The second project applied the previously developed methodology with success. The methodical approach resulted in a more efficient process with fewer committed errors. Time was saved and the validation of the newly created tests ran much smoother than the validation of the first assignment. The positive impact that a clear methodology has on the completion of a task was witnessed firsthand through the evolution of the process between both assignments. It should be linked to the exploration of the global engineering process because it holds true for any type of mission, in addition to testing campaigns. A further assignment was planned, but dropped for lack of time. It entailed the creation of tests based on personally defined test specifications. It would have brought another dimension of the engineering process with it, namely the process of defining specifications themselves.