“Transport chaos across England and Wales after major power cuts”, “Huge power cut paralyses Britain” and “Urgent investigation at National Grid after worst power cuts in decade” – the headlines in the Guardian, Daily Mail and Sunday Times did not mince their words when large parts of the UK were hit by a major power failure in August 2019. Millions of households were without electricity, no trains were running and the roads became dangerous because the traffic lights were out of order. A generator turned out because of a fault, as a result of which less electricity was being supplied than used.

Renewable energy puts the cat amongst the pigeons

With a reliability level of 99.9948%, the Netherlands secures power supply almost at all times. But, according to Popov, it is not inconceivable that the electricity supply in the Netherlands could become less reliable in the future. There is one key reason for this: the high utilization of renewable energy sources. Wind and solar power in particular are supposed to cause a sharp drop in CO2 emissions. However, totally revamping the structure of an electricity grid from a handful of coal-powered plants to thousands of wind parks and solar panels is bound to make the grid susceptible to disruption.

It is in the nature of the new phenomena that makes such a difference. In a “green” electricity grid, fault currents are usually with lower amplitude and contain higher harmonics, and as such they may have a negative effect on the efficiency of the grid. In addition, renewable sources have little to no inertia, which means that future electricity grids will be less stable than coal-powered plants. All these disturbances are very difficult to detect by applying classical protection.

‘In the past six years, my team and I have made a lot of progress in this complex research field,’ says Popov. ‘We've developed an efficient new algorithm and protection platform in the MIGRATE project, which can detect and immediately fix minor power outages. In the NWO-URSES project, we have created a new platform for collecting data in real time, which allows us to measure voltages and currents; as a result, we can swiftly detect the “sick” part of the grid and isolate it.’

Lightning remains unpredictable

So, have Popov and his team now tackled all types of power failure? No, not yet. As it turns out, scientists are still unable to cope enough with lightning strikes. In its search for earth, lightning usually strikes tall objects, such as electricity towers. Of course, these are well protected by lightning conductors and other mechanisms, but lightning still regularly strikes transformers.

For example, in June 2012 it happened in Nieuwegein. As many as 70% of residents – a total of 17,000 households – were without electricity for almost 24 hours. This not only caused annoyance, but also financial losses, resulting from shortage of electricity. This is not the only power outage to have been caused by lightning. ‘There is no way to predict the impact of lightning,’ says Popov. ‘In certain situations, the protection measures fail too. To optimise this protection, we need research into the interaction between lightning and the earthing system. As part of the SINTEF project, I am developing a unique interface to demonstrate how to design reliable protection.’

Text: Merijn van Nuland | Portait photograph: Thierry Schut