Kaleshwaram: First 400 KV GIS to power Kaleshwaram pumps

The first 400 KV gas insulated substation (GIS) intended to meet the energy needs of seven giant pumps being installed as part of the package 6 of Kaleshwaram project is all set to go operational. If everything goes as planned, it will be commissioned on August 21, according to irrigation officials.The gas insulated technology has been adopted to suit the needs of a massive underground pumphouse designed to lift two tmc of water. It was preferred over the conventional technology in view of its compactness and insensitivity to adverse environmental conditions within a massive irrigation system. 

Irrigation Minister T Harish Rao said the GIS system, though 1.5 times more expensive than the conventional power substation, makes huge savings on land acquisition. A 400 KV substation would require about 60 to 70 acres of land for its establishment, he said. 

The GIS has been built by three companies in less than over 6,000 sq yards of space underground. Sulfur hexafluoride (SF6 gas) is the main mode of insulation in gas insulated substations. The voltage withstanding capability of SF6 bus duct is the key factor that makes it an excellent electric insulator in technology, according to officials. They said that the constructional reliability aspects of the gas insulated substation in an underground location are high and hence the technology was opted.

This substation will be supporting seven pumps of 124.5 MW capacity each designed to discharge 3,200 cusecs each. Seven pumps supplied by the BHEL will be costing Rs 2,520 crore. The department is spending Rs 360 crore (excluding the cost of civil works) on each of the pump. The GIS will supply 900 MW required by all the seven pumps, which have been designed to lift two tmc of water a day.

K Penta Reddy, advisor to Irrigation Department on lift irrigation schemes, said the seven pumphouses together can draw as much water you require for example to fill Gandipet tank in a day or Hussainsagar lake in half a day. Two of the pumps are also ready for dry run which is likely to be scheduled on August 29. The wet run of the pumps will be planed once the water was released into the pumphouse.

He said that altogether six power substations of 400 KV capacity were planned to meet power needs of the pumphouses of irrigation projects. Five of them were coming up as part of Kaleshwaram and one at the Sitarama Lift Irrigation Scheme. The package 6 substation is the only underground one.

He said power lines were extended to the pump house recently and the pace of works on other components of the pumps was stepped up to make them operational by the month end to meet August deadline set by the Irrigation Minister.