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 Sept. 2, 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.