standards / manuals / guidelines for small hydro development - AHEC

12.0 TankskV kV kV kV11 12 28 7533 36 70 170The main tank body excluding tap-changing compartments, radiators and coolers shall becapable of withstanding vacuum given in the following table:Highest systemvoltage kVUp to 72 kVMVA rating Vacuum gaugepressure kN/m 2Up to 16 above 34.71.6 & up to 2068.0(mm of Hg)250500Above 72 kVFor all MVAratings100.6476013.0 Pressure Relief DeviceThe pressure relief device shall be provided of sufficient sizes for rapid release of anypressure that may be generated within the tank, and which might result in damage to theequipment. The device shall operate at a static pressure of less than the hydraulic testpressure for transformer tank. Means shall be provided to prevent the ingress of rainwater.Unless otherwise approved the relief device shall be mounted on the main tank, and, if onthe cover, shall be fitted with skirt projecting 25 mm inside the tank and of such a designto prevent gas accumulation.14.0 Anti Earthquake Clamping DeviceTo prevent transformer movement during earthquake, a claming device shall be providedfor fixing the transformer to the foundations. The contractor shall supply necessary boltsfor embedding in the concrete. The arrangement shall be such that the transformer can befixed to or unfastened from these bolts as desired. The fixing of transformer to thefoundation shall be designed to withstand seismic events to the extents that a staticcoefficient of 0.3g applied in the direction of least resistance to that of loading will notcause the transformer or clamping device as well as bolts to be over stressed.15.0 Fittings and Accessories(a)(b)(c)(d)Rating and diagram plate2 Nos. earthing terminalsCover lifting lugs.Skids and pulling eyes on both directions.3-11