Three units of Birsinghpur-based Sanjay Gandhi Thermal Power Station had shut down between 2.30 and 2.45 pm due to some snag in frequency system on Friday. But the snag was overcome within two hours and the three units started generating power as earlier. Meanwhile, the work of repairing a 500 MW unit of BHEL at Birsinghpur is fast progressing and this unit too is expected to resume power generation by Sunday morning. According to information received from Energy Department, all other power generation units in the state are working normally.