Security of supply
As the manager of the Dutch high-voltage grid and a large part of the German high-voltage grid, one of our main tasks is to make sure the infrastructure – the substations, power lines and cables – is always in good working order.
Regular maintenance of the infrastructure helps to minimise the risk of power failures, damage to the environment and safety incidents. We do this in the best possible way and at an acceptable cost. After all, our customers expect a reliable energy supply at a reasonable price. We therefore pay considerable attention to new maintenance methods and techniques so that we are continually improving.
Our high-voltage transmission grid spans more than 22,000 kilometers and high voltage substations. We take preventive measures to ensure it always functions well: we carry out regular inspections and maintenance work. If there is a fault, we repair it. Such faults, however, rarely lead to power outages in our network.
The substations are equipped with transformers. These increase or decrease the voltage so we can connect 380 kV power lines to 220 kV lines and to the regional grid operators (50 kV and below). Transformers have a long lifespan and can work for decades. We therefore inspect them regularly, along with the other equipment located in and around the transformer.
Power lines and masts
Power lines and pylons are relatively low maintenance. They last for decades, with pylons requiring little more than an occasional new coat of paint. We inspect the connections every 8 to 10 years and randomly carry out top-to-toe mast inspections. Parts of the mast that do sometimes need replacing are the insulator strings, which separate the live power lines from the pylons, and the spacers, which keep the lines far enough away from each other.
Every year, we carry out aerial inspections by helicopter of the conductors, the suspension and the buildings near the power lines. We also maintain the trees and plants around the substations, pylons and high-voltage lines so they don’t obstruct the energy supply.