UPGRADATION OF BER 66 by 11 KV TRANSFORMER AT MRS UNDER GE I RnD EAST BANGALORE

Power transformer step down, outdoor type of capacity 8.0 MVA (8000 KVA) 66 KV/11 KV, 3 Phase, 50 cycles AC with on load Tap Changing arrangements (with remote control panel operation) on 66 KV sides to vary secondary voltage from (+) 5% to (-) 15% in steps of 1.25 % (16 steps), impedance 7.35 % at normal / common tap No. 7 including suitable marshalling box and HV terminals 3 Nos outdoor bare bushings with sockets and LV Terminals connectors to connect the transformer with HT 11 KV XLPE power cable of size 400 Sqmm x 3 core with aluminium conductor and on secondary additional neutral with one No. solid porcelain type out door bushings with sockets on the transformer lid for earthing purpose complete in all respects with standard accessories and fittings conforming to IS-2026 primary side delta and secondary side star complete all as specified and directed. Make: ABB / SIEMENS / BHARAT BIJLEE / CROMPTON GREEVES / ALSTOM(GEC)/BHEL . The salient features of the transformer shall be as below: - (a) (i) Transformer shall be DYN 11 vector group oil + A3 immersed naturally cooled, double wound electrolytic copper winding core type, Radiator cooled MS tank complete with first fill of transformer oil as per IS-335 with ONAN cooling system. The temperature of oil shall not rise 50 / 55oC over ambient. Transformer shall be painted with two coats of synthetic enamel paint with two coats of epoxy paint as per IS-632.

Standard Fittings: (ii) Rating and diagram plate alongwith levels whereever necessary. (iii) Earthing terminals - 02 Nos. (iv) Lifting Lugs (v) Thermometer pocket. (vi) Air release hole with plug. (vii) Oil filling hole with plug on & incl conseravator with drain valve & plug. (viii) Digital type oil indicator on one side of conservator with minimum and maximum oil level marking. (ix) Dehydrating breather - 01 No. (x) Oil conservator with drain valve and plug. (xi) Sampling valves, top and bottom. (xii) Under base with flat treaded bi-directional rollers. (xiii) Drain cum bottom filter valve with plug. (xiv) Top filter valve with plug. (xv) Explosion vent with diaphragm, equalizer pipe (pressure release device). (xvi) Jacking lugs and hauling holes. (xvii) Inspection cover. (xviii) Detachable radiators with shut off valves between radiators & tanks. (xix) Radiator with air release hole and isolating valve. Oil drain hole with plug and lifting eye all as per manufacturer's standards. (xx) 150mm dia oil temperature indicator stem type.

(xxi) Double float Buchholtz relay with two set of contact & isolating valves. (xxii) 150 mm dia winding temperature indicator with maximum indicating pointer and resetting device. (xxiii) 100 mm dia magnetic oil level guage with low level alarm. (xxiv) Terminal arrangements. (xxv) Suitable wheels (width distance should be as per Board Guage rails on GI structure. (xxvi) Marshalling box. (xxvii) Neutral Grounding Resister suitable for 8.0 MVA transformer in out door floor mounted enclosure suitable for 45 Degree centigrade Ambient temperature and temperature rise 300 Degree centigrade all as approved by GE. (xxviii) Neutral current transformer 11KV ratio 420 - 240 / 1-1-1A, core 1:5P:10, core 2:1.0, core -3 class PS out door type class PS, knee point voltage 120 V @ vk/2 1 max > 30mA for restricted earth fault protection to be connected with neutral bushing of 8 MVA, 66/11 KV transformer through copper flat strip mounted on GI structure. (xxix) Indoor type Remote Tap Changer Panel (RTCC) with Automatic Voltage regulator and necessary indications. (b) On Load Tap Changer (OLTC), out door design weather proof, oil immersed, high speed, non inductive transition type employing, snap switches combining both selector and diverter duties housed in a self contained single compartment and mounting externally on transformer at suitable place. Make: Easun MR / CTR / CGL /OLG On load tap changer shall have following components: - (i) High torque electric motor suitable for 420V 3 phase 50 cycles AC supply including connected cabling. (ii) Motor drive and energy accumulator.

(iii) Motor isolating device with over load protection. (iv) Raise, lower control for local operation. (v) Local / remote control selector switch. (vi) Raise / low limit switch. (vii) Retainer switch. (viii) Stepping relay. (ix) Anti-condensation heater with switch. (x) Inter locking between manual and electric operation (a) Handle for manual operation (b) Auxiliary Transformer (xi) Main isolating switch with set of fuses. (xii) Insulated terminal board (with connector) for transformer tap leads. (xiii) Mechanical tap position indicator with handle. (xiv) Tap changing operation counter. (xv) Rating plate. (xvi) Driving mechanism chamber locking arrangement. (xvii) Un-drilled gland plate for cable entry. (xviii) Terminal strips. (xix) Drain cum filter valves. (xx) Stopers to prevent over travelling of mechanism. (xxi) Indoor floor mounted remote control cubicals (RTCC Panel, AVR relay) with rear accessories with wiring.

(a) Remote tap position indicating meter digital type. (b) Tap change in progress signal lamps with belt. (c) Raise / lower push buttons for remote operation. (d) Inside illuminating lamp with door switch. (e) Supply on signals. (f) On / Off indicating lamp for individual cooling fans. (g) Suitable 3 core rating Transformer. Note: (a) Single limb IMPULSE TEST AND HEAT RUN TEST shall be carried out at Manufacturers factory or approved laboratory and the rate for the same is deemed to be included in the quoted rate. (b) pre dispatch Inspection and testing of Transformer at manufacturers factory premises shall be carried out by the representative or officer nominated by Accepting officer and all tests pertaining to IS : 2026 shall be carried out. The quoted rate deemed to include the cost of all arrangements by the contractor. (c) Site testing: Insulation resistance oil temperature alarm trip, Winding temperature alarm and trip, Buchholtz relay alarm and trip, Low oil level alarm, testing of annunciation systems by auxiliary relay triping of transformer, Polarity marking and phase sequence, Ratio test, dielectric strength and filtration if required should be carried out in presence of the Engr-in-Charge & authorised Engineer of the transformer manufacturer. The quoted rate deemed to include the cost of all arrangements by the contractor.

(d) Control cables shall be measured and paid separately under the respective of item of schedule. (e) Foundation and civil works as per manufacturers recommendation and shall be deemed to be included in rate quoted above. (f) Excavation, earth work & GI & copper strip for earthing shall be measured and paid separately. (g) The stud for neutrals shall be sufficiently long to fix 2 Nos strip earthing. (h) Cost of cable entry box on LV 11 KV side for 3 core XLPE 400 sqmm XLPE cable shall be deemed to be included in the rate quoted. (j) Routine test as per IS 2006 shall be conducted and test certificate shall be furnished. (k) Unit price deemed to be included the connecting of trip contacts of Buchholtz relay and temperature indicator of windings of oil to the trip coil in panel board. (l) RTCC and AVR shall be suitable for automatic voltage regulation master follower scheme with tap position indicator as per tap indication in the OLTC mechanism, RTCC should be provided with control gear irrespective of fan ON / OFF indication, auto and manual control switch AC supply on and Tap changer in progress indication lamp, tap struck indication and alarm. (m) The erection of transformer shall be done under the supervision of manufacturer authorised representative. Contractor duly signed by authorised representative manufacturer and Engineer-in-Charge / representative of GE.

(n) LT Armoured control cables shall be measured and paid separately under relevant items of this schedule. (o) Civil Work: All civil works including RCC / PCC Footing, Foundations, platform, plastering and finishing etc related to suitable for 8 MVA Transformer platform and also for Control Panels / equipments for installation and commissioning new Transformer. The depth of the foundation shall be as recommended by the manufacturer. The foundation drawing for Transformer as per Manufacturer recommendations, shall be submitted by contractor to the Engr-in-Charge and the same shall be approved by GE. The Rates for new founadation, PCC works exc etc shall be deemed to be included in rate quoted above. Dismantling of existing old 5 MVA transformer platform including foundation related civil works completely and clearing of site etc shall be measured and paid under the respective item of Schedule. (p) DYNAMIC SHORT CIRCUIT TEST shall be carried out in presence of the representative or officer nominated by Accepting Officer at manufactures factory or approved laboratory. The quoted rate deemed to include the cost of all arrangements by the contractor.

Supply, lay, connect, testing and commissioning of HT XLPE cable of size 400 sqmm 3 core, XLPE insulated, insulation screened with extruded semiconducting compound in combination with copper tape (0.3 KA for one second), cores laid up, extruded PVC inner sheath with fillers, galvanised steel flat strip armoured and overall PVC sheathed cable, electric power cables (heavy duty) suitable for earthed system with aluminum conductor, 11000 V grade cross sectional area mentioned above confirming to IS : 7098 Part-II / 85 with latest amendments laid in trenches / ducts, fixed on walls / panels all as specified and directed. Note: - a) The High voltage test and other relevant test shall be carried out at site after laying and before commissioning and test report shall be submitted in triplicate to GE. b) Excavation, earthwork, sand cushioning, PCC cable cover protection pipe and joints shall be measured and paid separately.

Cable jointing kit for 11000 V grade cable for indoor termination cold shrinkable type complete with jointing material and accessories suitable for 3 core XLPE armoured aluminium conductor cable of size 400 sqmm complete all as specified and directed.

Cable jointing kit for 11000 V grade cable for outdoor type termination cold shrinkable type complete with jointing material and accessories suitable for 3 core XLPE armoured aluminium conductor cable of size 400 sqmm complete all as specified and directed.