Historical Choice: From 230 VAC to 350 VDC

NPR 9090: The first Practical Guideline for DC installations

"2018 could well be a historic year in the development of international electrical engineering, with the Netherlands setting the tone: from 230 Volt alternating current (AC) to 350 Volts direct current (DC) .The new core colors for DC are red, white and blue. This and more has been recorded in our country in the very first NPR 9090 for DC installations, which appears alongside the familiar low voltage standard NEN 1010.

This will be the premise of the Dutch electrotechnical standards committees (NEN) during the international consultation on a separate standard for DC installations. In recent years, direct current in our country has started on a strong advance on the electrical installations in homes, buildings and the infrastructure. This requires adaptation of traditional AC installations based on new standards. In addition to the new standard voltage and core colors, many other DC cases have been recorded in the Dutch Practical Guideline NPR 9090," states chief editor Harrie Heemskerk in the foreword of the Mag1010, issue 2018-04 by the NEN.

The NPR 9090 was created in the DC workgroup of the Dutch Standardization Committee (NEN), a workgroup that was established in 2013 to examine standards on DC. This work group was created thanks to the Green Deal that Direct Current BV had signed with the Ministry of Economic Affairs in 2012, with Harry Stokman, director of Direct Current BV, as chairman of the DC working group. For his active role within the International Electrotechnical Commission (IEC) in the field of LVDC standardisation, he received the 1906 Award by the IEC in September 2018.

Excerpts from the article in the Mag1010:

This first NPR 9090 appears in The Netherlands alongside the old familiar NEN 1010 for the AC installations, which also contains a limited number of DC provisions, but for the time being it will have a completely different character than the current NEN 1010.

'New standards are being developed for microgrids and neighborhood batteries'
The new NPR 9090 is a purely Dutch affair, explains Joost de Koning [member of the DC workgroup]. But with this our country does have a leading position in the global consultation on international standards for DC installations.

'The Netherlands has been at the forefront of the direct consumption of DC for a number of years'
Although the use of direct current in our country is getting off the ground faster and faster, most electro technicians have no experience in practice. Moreover, in contrast to the scientific institutes, technical vocational training is not really focused on that either. The first NPR 9090 is therefore mainly focused on the security of DC installations. Design, inspection, maintenance and management are subjects that are added at a later stage.

[De Koning] explains why the 'War of Currents', just after almost two centuries, flares up again. This is mainly due to the need to make the surrounding environment more sustainable, required for the energy transition, and the circularization of the economy. Only in this way, CO2 emissions and the consumption of rare raw materials will be limited. That's why we 'go from oil, coal and gas' to 'all electric'.

This will result in a strong growth in electricity consumption. This electricity must be generated as sustainably as possible, from sources such as the sun, wind and water. Not just decentralized by the end users, but also centrally from large solar fields on land and wind farms at sea. This electricity is exchanged internationally as DC over large distances at a high voltage level. With AC, far fewer distances can be covered and too much power loss would occur.

This whole process is more efficient with DC, which is transformed and controlled by smart electronics and ICT. This did not exist at the time of the first AC/DC battle, but nowadays they do. As a result, we can now organize the generation and distribution of electricity differently and thus make it more sustainable.