GAIL (India) Limited

22ii) Tappings : OFF load tap changing arrangement on HT side for variation of LT voltage from+/-2.5%,+/-5% &+/-7.5%iii) Temperature rise: Not to exceed 40 deg.C by thermometer in oiliv) Type: Outdoor as specified in the Schedule.v) Terminals: Cable end boxes on LT sidesvi) Cooling: Natural oil cooled (ONAN).3.2 Fittings and Accessories:i) Lifting Lugs: Necessary-lifting lugs shall be provided to lift the transformer without disturbing theconnections.ii)iii)iv)Swivel type rollers: 4 Nos. Bi-directional rollers shall be fitted on cross channel at the bottom of thetransformer so as to facilitate the movement of transformer in both the directions.Oil-conservator: Suitable size of oil-conservator shall be provided. The conservator shall have oil levelgauge with marking for minimum level and oil filling hole with a cap.Air release valve: An Air release valve shall be provided on the lop of the lank cover to facilitate therelease of the entrapped air while filling of oilv) Breather: Sufficient capacity of indicating de-hydrating silica gel breather shall be provided.vi)Drain-cum-oil filter valve: At the bottom of the transformer drain-cum-oil filter valve shall be provided.vii)viii)ix)Earthing terminals: Two separate connecting terminals shall be provided on both the sides of the tank forearthing.Oil-load tap changing switch. The transformers shall be provided with an externally operated off-load tapchanging switch with handle with position indicating plate and locking device.Diagram and rating plate: The transformer shall be fitted with a diagram and rating plate indicating thedetails of the transformer connection diagram, vector group, tap changing diagram etc.x) Dial type thermometer: Dial type thermometer of range 0-100 degree celcius shall be provided.xi)Explosion vent: The transformer shall be fitted with an explosion vent of suitable size.xii)The transformer shall be provided with first filling of oil. The transformer oil shall conform to the latestrelevant Indian Standards.3.3 Testing:The following tests shall be conducted at the factory before dispatching and the test certificates shall befurnished.i) Measurement of winding resistanceii) Ratio, polarity and phase relationshipiii) Impedance voltageiv) Load lossesv) No load loss and no load currentvi) Insulation resistance