by Alex Apostolov, Editor-in-Chief

It's all about the Tools

IEC 61850 is already a common reality in thousands of substations around the world. GOOSE messages are flying and delivering performance better than the hardwired solutions. Some digital substations are already in service. But why do we still have people that are not taking advantage of the significant benefits that IEC 61850 provides us?

And this requires maintenance. In order to avoid any misunderstanding it is best to start the discussions on this topic in this edition of the magazine by common industry definitions. According to the IEC 60050 International Electrotechnical Vocabulary (Electropedia):

  • Maintenance is the combination of all technical and administrative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function
  • Maintenance Test is a test carried out periodically on an item to verify that its performance remains within specified limits, after having made certain adjustments, if necessary

If we think about these definitions from the point of view of 3Q (this is a new acronym for the three questions that we should always ask at the start of any activity – what are we doing, why we are doing it and how are we going to do it?):

  • The answer to the first question is straight forward. We do maintenance because we have to ensure that all protection, automation and control devices and systems can perform their required functions according to their design specifications
  • The answer to the second question can start with the traditional “It depends!”

It depends on who you ask. For some people the answer is “Because this is what we always do.” For others it is because there are regulatory requirements, i.e. they have to do it, like it or not. For many it is due to the fact that the importance of PAC systems for the security of the electric power system is very high and they may not be sure that everything will function as required when necessary.

The last is the best reason to do it, because it will drive us towards a more efficient answer to the last of the three questions. If we are doing the maintenance in the first two categories, we may be also doing the maintenance and the related testing using tools and methods that are not appropriate for the devices that we are testing. We may also be doing testing in cases when it is not really necessary. And as many local and wide area disturbances have shown, they have been the result of human errors during maintenance testing, in some cases even leading to blackouts costing billions of dollars or other currencies.
To go back to the question in the title, the answer, as usual, is “It depends.” It depends on:

  • The PAC technology we are using,
  • The condition monitoring functions that have been enabled,
  • The criticality of the site and
  • Many other factors

So, the second part of the answer is “Test only when necessary using the most efficient methods and technology.” This will ensure that you will not have to solve any problems, but that you will avoid them.

“A clever person solves a problem. A wise person avoids it.”


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