DNV’s power failure investigation in the Netherlands reveals special circumstances and provides important learning points

TenneT commissioned DNV to conduct an extensive power failure investigation after an incident in a high-voltage substation, the summary of which is now publicly available.

DNV was commissioned by TenneT, the Dutch national electricity transmission system operator, to conduct a fully independent and extensive power failure investigation (PFI) of the incident that occurred at the new 150 kV substation Dronten Olsterpad in Flevoland on 2 September, 2022. This event, caused by a prolonged short circuit, led to arcing, and over-heating and smoking of the feeding overhead lines.

As an independent expert, DNV deployed experienced PFI specialists to examine the technical, human and procedural aspects that played a role in the power failure and identify its root causes and influencing factors. DNV’s team of experts observed that actions were independently performed in the Dronten Olsterpad and Lelystad substations that resulted in the short-circuit, which was finally cleared by the protection scheme after 4:22 minutes. A combination of human aspects and technical deviations in the protection scheme and its back-up prevented the system to switch it off instantly as expected.  Nonetheless, DNV concluded that TenneT acted quickly to mitigate the disruption. Overall, the incident shall be considered an extraordinary situation. DNV’s investigation led to important learning points, which resulted in clear recommendations that will help reinforce safety procedures and their application; the full summary of DNV’s report is now publicly available on TenneT’s website.

The incident did not cause personal injuries, but had wide-ranging consequences – including a power outage in the region, a temporary closure of the A6 motorway and the N309 regional road and a long-lasting interruption of train traffic on the Hanzelijn railway track between Dronten and Lelystad. This event resulted in the involvement from the Dutch regulator.

“For many decades, DNV has built comprehensive expertise, covering the complete range of power components and power systems, and is a respected fully independent reference in forensics of energy systems. As stated in our purpose, to “Safeguard life, property and the environment”, safety is at the core of our commitment to the energy industry, which we continue to help be ever more secure and efficient,” declared Prajeev Rasiah, Executive Vice President for Energy Systems, Northern Europe at DNV.

“Our experienced Power Failure Investigation experts are trusted by industrialists, insurers, governments and regulators to uncover the underlying root causes of power outages, and to formulate recommendations to prevent future occurrences and their wide-ranging and potentially serious consequences. The knowledge we have acquired for every grid component and power system aspect through over a hundred annual independent investigations around the globe, and with access to our network of specialized facilities, guarantees that we can deliver consistent levels of quality and reliability,” added Peter van der Wielen, Business Director for Power Failure Investigations, Energy Systems at DNV.