Norway tested a new cable – as a result 1400 MW were imported from Germany by mistake

The incident caused a frequency deviation that was registered with all our Nordic customers. Background to the incident was the new direct current cable between Norway and Germany. When it was tested, an error occurred. The mistake caused seven gas turbines to be started up in Sweden.

“A dramatic event,” says a Swedish operations manager.

First, the frequency in the Nordic electricity system increased by 0.5 Hz due to the power supply. When the transmission in Nordlink was stopped manually, the frequency dropped rapidly by about the same amount.

In total, the frequency ranged from 50.5 to 49.5 Hz. In total, it was about 967 millihertz in frequency variation.

“I cannot see that such a large variation in such a short time has ever occurred before,” says Pontus de Maré, operations manager at Svenska Kraftnät.

Electricity producers are usually the ones affected by large frequency deviations.

For more detailed information about the event, click here.