The fire broke out when a cable at the pump connecting cooling tower I and II burst, officials said.
The CISF jawans brought the fire under control during which constable Rajendra Singh received injuries, Chief Engineer R Bansuri told reporters here.
Singh was later admitted to a hospital with burns, he said.
Efforts are on to restart production in the three units, he said, adding the plant supplies power to Jharkhand, Bihar, West Bengal and Odisha.
