Electricity supplies were restored to all consumption points in the Czech Republic by yesterday evening, following a widespread power outage that left one million domestic customers without electricity.
Speaking at a press conference yesterday evening, Minister of Industry and Trade Lukas Vlcek and the head of the transmission system operator CEPS Martin Durcak said the outage was the result of the cascading effect of a series of technical failures, starting with a fallen phase wire. The cause of its failure is still under investigation.
After a meeting of the Central Crisis Staff, Prime Minister Petr Fiala told reporters that the possibility of a cyber attack had been ruled out.
Around midday yesterday, large parts of the Czech Republic were hit by widespread power outages. Parts of Prague and the Central Bohemia, Liberec and Usti regions, as well as eastern Bohemia, were without power. At around 14:50, CEPS announced that all substations had been restored to service.
“The initial problem occurred when a phase conductor, or simply a very high voltage cable, failed,” Vlcek said. “This subsequently triggered a cascading effect that knocked out nine substations. For a certain period of time, about one million points of consumption in the Czech Republic were without electricity.” He added that the outage had now been averted.
According to CEPS, the main mechanical cause of the blackout was the rupture of a phase conductor that transmits electricity between power plants and substations. This knocked out the high voltage backbone of the V411 line, which is used for high power output from the power plants and for transmitting electricity over long distances. Another failure that followed was the outage of a unit at the Ledvice power plant in Teplice. The V208 line connecting the substations was also overloaded. The large Krasikov substation in the Usti nad Orlici district in East Bohemia was also affected. In this context, the CEPS chief also explained that a fault at a facility in one area can affect distant locations within the system.
“There was a technical cause at the beginning and the consequences of another fault behind it,” Durcak said. “Why these phenomena occurred will be the subject of further investigation. For example, it could have been a combination of high temperatures or other factors. However, we have no details on this now.”
In a normal situation, Durcak added, individual disturbances should not build on each other. He said the power engineers should be able to repair the equipment by this morning at the latest.
Vlcek dismissed the possibility that the cause of the problems was overloading of the grid due to large overflows from Germany in connection with increased renewable energy production. According to CEPS data, the overflows did not exceed normal levels during the outage period.
The minister also stressed that yesterday’s outage showed the importance of investment in the energy sector, in this case strengthening and modernising transmission and distribution networks. According to Durcak, CEPS has been preparing for several years to modernise the now damaged high voltage line, but he said it was a long process.
