A large electricity outage struck parts of the Czech Republic on 4 July. The blackout affected large sections of Prague and several regions.
According to the Czech transmission system operator ČEPS , shortly after noon on 4 July a phase conductor failed on transmission line V411. The cause of the failure is still being investigated. The incident cut power to eight major substations, five of which were restored within a few hours.
Initial reports indicate that the failure of a phase conductor on HV line V411 triggered a frequency imbalance and partial system collapse. Investigators have ruled out a cyberattack as the cause. The specific cause of the rupture remains under investigation, with heat-related stress or equipment fatigue considered the most likely causes.
All repairs were completed by the early hours of 5 July.
Václav Skoblík of United Energy Commodities said the outage underscored seasonal imbalances—high solar output paired with low summer demand—and called for improved local storage and consumption flexibility.