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Over the last 20 years, I have been involved  with trainings, lectures and work, in several countries, to help manufacturers, certifiers and testing labs teams to develop and analyze projects and design issues for substation items like medium voltage (IEC 62271-200 and 307) and low voltage (IEC 61439) systems.

I learned that, in developed countries and  very few developing ones, the main demand is usually on training of  teams to make them more capable to do their own projects, without the help of external consultants. They want to learn “how to fish”  and not only “to buy the fish”.  Another way of doing things, used in developing countries, with rare exceptions, the focus is in “outsourcing” the execution of the design or project rather than train their own  teams to developed it  alone. They prefer to invest again and again to do the calculations than to invest much less, a single time, to make their team more capable.

There are  vantages and disadvantages in  outsourcing the project execution or to invest in project teams training and education. It is not the intention of this post to discuss which ones are more appropriate. This is a choice of companies based on their historic experience. I heard from several managers of companies that  they think that, once a designer is trained, ends up going to another company to earn more. Maybe this kind of thinking explain why  project  teams were far more numerous and well-prepared in the 1970s and 1980s than they are today. There is a huge difference between investing in buying powerful calculation software tools and having a really competent team to use it and to interpret the results well.

I think that the preferences for strategies of outsourcing, or not, are linked to the level of education. Developing countries companies invest much less in training and education. For the electric industry professionals, the reading of the brochure Cigrè 740 (2018) may be especially useful.  The title is "Contemporary Design of Low-Cost Substations in Developing Countries”. Possibly it is the only worldwide document that has a complete chapter devoted to training for the electrical sector.

 About the dilemma between “to outsource x to train own teams”, in developing countries, it is usual to replicate old projects from developed countries rather than seek innovative solutions that are more appropriate to local conditions. Little or no availability of testing laboratories makes the picture more difficult.. If you compare the technical capabilities of the teams of international manufacturers in their countries of origin or in the developing countries, where they manufacture most of the equipment, you will notice the differences. I had the opportunity to make such comparisons along many participation in the IEC and CIGRE working groups and in the training, sessions carried out in many countries, including the one where I live.

I would say that some Asian countries have learned much more about this issue, over the past 30 years. They  invested much more than all in training and are no longer copiers of projects. They reached the top of the technological pyramid and when they succeed to make these benefits reach the base of the pyramid, as they are already doing, they will be unbeatable.

Using the opportunity, I leave here some typical questions that developers of products for substations need to  respond in their daily life. They may help to assess the capabilities of project teams and the eventual need of training

Some questions of the day to day of designers

1)     In a low voltage switchboard, the connection between the busbars and the circuit breaker terminal is usually the warmest point of the circuit, in the temperature rise test. As an example, the feeding  2x80x10mm busbars are attached to the circuit breaker by a connection with 4 screws. The superimposed connection area is 80x60 mm. Someone proposes to replace the connection with another smaller superimposed area  like, 80x30 mm, using only two screws, instead of four. Would the result be a higher or lower temperature rise? The answers are in the concepts of IEC 60943.

2)     A medium voltage panel for indoor use has no natural ventilation openings, with or without filters. It did not pass the temperature rise test because the temperature rise of the silver-plated terminals, connecting to the base of the current limiting fuse, was 10 K above the limit allowed by the technical standard. The designer intends to make two 200 cm2 openings at the top and bottom of the panel with a thick filter. The question is: the extra 10K would be reduced and the equipment would pass the test? And if you do only one 200 cm2 opening in the , instead of two ?

3)     A manufacturer designed a long busway with the bars "upright”. Passed the temperature rise test but did not pass the short time withstand current and crest test (electrodynamic forces during short circuit). It is proposed, simply, to change the position of the bars to "horizontal". The calculations show that it would solve the mechanical problem under short circuit but is suspected to have a negative impact on the already approved temperature rise test. Is this a proper solution?

4) A medium voltage switchgear rated 24 kV – 20 kA is to be sold to a client user which requires the test report for the “internal arc test “. A similar design  rated 17,5 kV – 25 kA was tested and approved, and a test report is available. Is it necessary to test the prototype 24kV – 20 kA? Which arguments to use to test or not ?  

Sergio Feitoza          ***     E-mail

Sergio Feitoza Costa's picture

Thank Sergio Feitoza for the Post!

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Dr. Amal Khashab's picture
Dr. Amal Khashab on May 24, 2020 1:35 pm GMT

I prefer the utility to build its own design team supported with updated software. Also, I recommend that utility to make use of its team gained capabilities through doing works for other utilities. This is hunting two birds by one stone. Although it will need an upfront cost, it will pay back sooner or later.

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