Since launching the more robust version of its neutral electromagnetic couplers with earthing resistors and auxiliary transformers (NECRTs), ACTOM Distribution Transformers (ADT), a division of electro-mechanical equipment manufacturer ACTOM, has supplied multiple units to operations contending with the harsh conditions synonymous with Africa.

Designed to exceed the robustness of the previous NECRTs model, the latest version was developed in close collabo­ration with Eskom. The new design extends previously applied specifications to encompass a voltage range from 2.2 kV to 44 kV, an ampere range from 360 A to 2 800 A and a power rating range of between 50 kVA and 500 kVA for the auxiliary transformers of the NECRTs.

“We worked together with a delegation of Eskom engineers – as­sisted by an international expert from Germany on their side and a local spe­cialist consultant on our side – to develop the new set of Eskom specifica­tions,” says ADT Divisional CEO Lee Mbenge.

“This was after we had been as­signed by Eskom to do a root cause analysis of the original product, which resulted in us determining that the specifications applicable were not adequate for the conditions they were exposed to.”

NECRTs are used in transmission and distribution substations for earth­ing power transformers and are also extensively deployed in renewable energy collector substations.

“The new NECRTs model is op­timally designed to withstand the high harmonic content from the invertors in renewables’ collector substations,” Mbenge points out.

To date, since the new NECRTs were launched in January 2013, Distribution Transformers has made sales to several independent power producers and data centres in the local market. It has also sold units to mining custom­ers in Zimbabwe, Botswana, Ghana, Namibia, Lesotho and Zambia.

The division’s most recent order involved supplying 49 NECRTs for newly-established substations that support substantial extensions to the large Kamoa-Kakula underground copper mine, in the Democratic Republic of Congo.

ADT won its first order to supply NECRTs to the Kamoa copper project in June 2020. The order, delivered at the end of that same year, comprised five 33 kV 100 A and four 11 kV 300 A units. The second order placed in February 2022, comprising two 33 kV 100 A and five 11 kV 300 A units, was delivered in mid-2022. A third order, comprising seven 33 kV 100 A and 14, 11 kV 300 A, units, was delivered at the end of 2023.

ADT also delivered a fourth order for five 33 kV 100 A and five 11 kV 300 A units in mid-2024. A fifth order for two 33 kV 100 A units was delivered for the Kamoa copper smelter project at the end of April this year.