Bharat Heavy Electricals has commissioned a 77 mw unit at Hindustan Zinc's (HZL) captive power plant in Rajasthan.The unit is part of the Rs 406 crore contract to set up a 154 mw captive plant on turnkey basis for HZL at its upcoming Chanderia lead zinc smelter plant in Chittorgarh, a Bhel release said.The first unit has been synchronised in 20 months, it said, adding work on second unit was progressing well and the project is likely to be completed shortly.Bhel's scope of work in the project envisaged design, manufacture, supply and install the plant on turnkey basis.The company's Bangalore-based electronics division supplied the control system and the auxilliaries were supplied by its Ranipet plant, it said.