Grid Corporation of Odisha(GRIDCO) director (commercial), P K Pradhan said distribution of electricity was disrupted in the entire state except some parts of the western region.
"We are not aware of the reasons behind the grid collapse. But we are trying to restore power supply on a war footing. Our men are on the job," he said.
Efforts are on to restore power supply in phases, he said, adding some arrangements have been made to provide electricity in some areas of the capital city immediately, Pradhan said.
The state secretariat, buildings housing important government offices and in nearby areas power supply was restored within an hour, said a senior official.
Train services in the state were hit barring western areas like Sambalpur, Rourkela, Jharsuguda, Bargarh and Bolangir, where there was no disruption in power supply, official sources said.
Priority is being given to restoring supply to important hospitals, airport, railways and other vital installations, they added.