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TOV Test on a 525kV DC Cable System: Interview with Franchi Bononi, Prysmian Group R&D VP for BU Projects

TOV Test on a 525kV DC Cable System: Interview with Franchi Bononi, Prysmian Group R&D VP for BU Projects
09 . Aug . 2022

Recently, KEMA Labs ( CESI ’s Testing, Inspection and Certification Division) has carried out the first TOV (Transient Over Voltage) test on a 525kV DC Cable System , manufactured by Prysmian Group R&D . This new and important goal for the HVDC Cable Sector has been reached in our KEMA Labs Mannheim HVDC Laboratories.

Due to the importance of such a ground-breaking project, we have interviewed Stefano Franchi Bononi, Prysmian Group R&D VP for BU Projects , in order to go deeper into the several steps that led to the project’s successful completion. Below, you can find Mr. Franchi Bononi’s full interview.

The first TOV (Transient Over Voltage) test carried out by KEMA Labs involved a 525kV DC Cable System, manufactured by Prysmian Group. What made you choose KEMA Labs as the right partner for this project?

TOV represented the new challenge for the high-voltage electricity laboratories committed to supporting the development of power transmission systems. A number of laboratories of different institutions had carried out simulations with simplified voltage waves, however, encountering major technological difficulties. Prysmian engaged with customers to carry out these tests with well-defined parameters very similar to those required by current international standards. In order to fully satisfy what was agreed with the customers, not only parameters and test methods, but also deadlines, we started a technical discussion with the world leader in electrical high-voltage test laboratories. We were looking for professionalism, expertise, availability, flexibility in facing new challenges and, of course, the best hardware available. In CESI, we found all this and started a fruitful collaboration that led to CESI being the first laboratory to carry out this test and Prysmian the first cable manufacturer to pass it.

What does this test mean for the future of cable systems?

This test was endorsed by the international scientific committee CIGRE and it was introduced in the recent TB 852 recommendations after a long discussion involving the world’s leading experts in the field. The world’s scientific consensus questioned what problems might arise with the increasingly widespread use of systems involving a bi-pole instead of the more traditional single pole with return cable. The most critical phase was identified as the failures that can occur in one of the two poles and the possible consequences on the second pole. At the same time, abnormal stresses can also occur with faults in the converter stations and/or during the on/off switching operation. The cable system and accessories that pass the new tests defined by the standards guarantee the robustness of future connections. Ultimately, realizing and passing this new set of tests guarantees the performance of the power transmission system by raising its quality and reliability to the benefit of the end user.

Do you envision the collaboration between KEMA Labs and Prysmian Group to continue on such projects in the future?

I think that the result we have achieved with this collaboration is the fruit of two groups representing two world-excellencies. The result achieved is there to prove it. With this in mind, we will clearly continue to work together with KEMA Labs in the future. We are already working together these days to optimize the testsetup and introducing some new methods in well-known tests (i.e.: superimposed impulses).

What does this achievement mean for Prysmian?

The result not only demonstrates Prysmian’s ability to take on new challenges but also the care with which it chooses its partners. At the same time, Prysmian proves the quality and reliability of its high and extra-high voltage power transmission systems. Once again confirming its world leadership.

Stefano Franchi Bononi was born in Ferrara in 1961, received a Degree in Electrical Engineering at Alma Mater Studiorum of Bologna in 1986. He has more than 30 years of experience in cables industry spent in Research and Development department of Prysmian Group, former Pirelli Cables. His experience includes accessories design (both telecom and energy), development of new generation of instruments for research activity, Chemical, Physical, Mechanical and Electrical Laboratories Management. He is currently Director of Prysmian R&D Projects Department. He is member of different international committee and working Group.

If you want to know more about the first ever TOV Test on a 525kV DC Cable System, as well as other ground-breaking projects and achievements in the TIC sector, read our latest issue of Testingly .

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