Automated Testing of Motor Protection IEDs

Author: Michael Albert, OMICRON electronics GmbH, Germany

The new technologies and the possibilities they gave to the protection engineers lead to a huge increase in the number of parameters which cannot be checked in the field any more. This applies to protection IEDs, including the ones protecting motors of different sizes. It is no longer sufficient to send the tester in the field with the command to test the protection device using a manually controlled test device with a current and voltage output.
There are many issues to be considered first and to recognize during the testing of motor protection IEDs.  Some of these are:

  • It should be clear what has to be tested: The tester has to know which parameter needs to be tested and which should not be. Sometimes this is not clear, because of new highly sophisticated algorithms in modern protection devices, or the availability of signals different than the traditional secondary currents and voltages
  • Which tools should be used: The way of testing has also changed or has to be changed because of the new technologies used in the test objects
  • The availability of state of the art testing tools that can make the work of field engineers or technicians more efficient

The requirements for improving the quality and efficiency of testing lead to the idea of using an object-oriented approach to testing, especially in cases with high repeatability, such as the testing of hundreds of similar or even identical motor protection IEDs in a large industrial facility. 
The standardization of the testing process allows it to be automated, resulting in significant cost savings, while at the same time improving quality.

Test Automation - What does it Mean?
The advantages of a standardized way of testing are:

  • The tester himself saves time for developing the test procedure: The test procedure is already defined, only the changed parameters have to be configured before the test of a new protection device starts
  • All test plans include the same tests, which means that the testing quality can be better controlled and in the end improved
  • Working together as a team is easier, as everyone is working with the same standards. The team members can exchange their experiences and share knowledge
  • A very important argument is that standardization can help to keep the know-how of the people in the company, and it documents the experiences of the company
  • New protection functions or new (improved) algorithms in protection functions can be recognized and the updated testing solution can be released to every tester at the same time. The development of such a test is only done once

However, there are different levels where unifying of relay testing can be realized. One possibility is to differentiate as follows:

  • Standard for testing a dedicated protection application. This defines “What is tested” for example. line protection or motor protection devices
  • Standard for testing a dedicated protection function. This describes “How a protection function is tested”
Protecting your electrical assets? today and tomorrow