PROVISION OF CERTAIN EM WORKS FOR IMPROVEMENT UPGRADATION ON 33 KV HT SUPPLY IN AF STATION SINGARSI

Amount

Supply,instatllation, testing and commissioning of HT automatic voltage regulator 1000 KVA, 3 phase, 50 Hz outdoor type, copper wound, oil cooled, class of insulation A, metallic body powder coated designed for input voltage 18-36 KV, 3 ph, 50 Hz and output voltage range 33 KV + 1% 3 Ph, ONAN, with housing of MS Fabricated tank filled with transformer oil with first filling of requiisite dielectric strength upto level,with all standard fittings like, digital temperature meter, adequate number of cooling radiators, lifting hooks one set alongwith bypass arrangement and testing as per relevant BIS all as specified by manufacturer and directed with following specifications :-

(i) Cooling - ONAN (Natural Oil Cooled) (ii) Ambient - Temp 50 Deg C max (iii) Housing - MS Fabricated Tank filled with transformer oil (iv) Installaton - Outdoor The unit shall consists of (a) Step down transformer double wound, delta /star connected (b) On load stepless rolling contact type regulator, auto wound, delta connected (c) Booster transformer, double wound open/open Automati control gear consistes of (i) One No of microprocessor based controller (ii) One reversing gear motor unit (iii) Two limit switches in order to avoid over running highest and lowest positions, chain drive, coupling devices and all electrical connections Transformer shall be housed in a seperate sheet steel tank fitted with radiators and mounted on Bi-directional rollers and shalll have the following fittings :- (a) Rating and diagram plate (b) Earthing terminals (c) Lifting lugs (d) Oil level indicator (e) Pressed stell radiators with shut off valves and air releasve plug (f) Drain cum bottom filter valve

(g) Oil conservator with drain plug (h) Thermometer pocket (j) Oil filling hole with plug on conservator (k) Double diahgragm explosio vent (l) Pressure reilef valve (m) Inspection cover with air release plug (n) Silica gel dehydrating breather (o) Bi directional rollers (p) First filling oil (q) Winding temperature indicator with alarm & trip contactts (r) Oil temperature indicator with alarm & trip contacts (s) Buchholz relay with alarm & trip contacts (t) Marshalling box

Regulator Parts shall be housed in a separate tank and shall have the following items: (a) Rating & diagram plate (b) Earthing terminals (c) Lifting lugs (d) Oil level indicator (e) Pressed steel radiators (f) Drain cum bottom filter vallve (g) Oil filling hole (h) Thermometer pocket (j) Silica gel de hydrating breather (k) Uni directrional rollers (l) First filling oil

1) AUTOMATIC CONTROL: For automatic correction of fluctuating supply voltage we shall provide Electronic Relay which will sense the output voltage and provide signal to the driving motor for necessary correction. II) MOTOR CONTROL: Raise/Lower push button control by means of small single phase reversible geared motor of the permanent capacitor type shall be provided. The Limit Switches shall be provided to restrict the travel at extreme positions. With this arrangement, it would also be possible to provide remote control of the Regulating Unit. The reversible geared motor would of 'STEP-SYN' type. III) HAND CONTROL: Hand Wheel will be located on the front of the regulator tank at convenient operative height.

MAXIMUM TEMPERATURE RISE: i) Of oil by thermometer 50 deg. C ii) Of winding by resistance 55 deg. C iii) Of hot spot temperature indicator 65 deg. C iv) Limit of hot spot temperature 110 deg. C TANKS AND RADIATORS: Tanks shall be of M.S. plates and structurals, electrically welded. The construction shall be robust and substantial, suitable for road/rail transport and to withstand vibration. Fixed type radiators will be provided for desired cooling. Tanks shall be provided with lifting lugs and Inspection hole with cover should also be provided. Oil conservators shall be mounted on bracket attached to the top cover on tank. Dimension of the conservator shall be such as to allow change in volume of oil due to change in temperature from 10 C to 95 C.

TANKS AND RADIATORS: Tanks shall be of M.S. plates and structurals, electrically welded. The construction shall be robust and substantial, suitable for road/rail transport and to withstand vibration. Fixed type radiators will be provided for desired cooling. Tanks shall be provided with lifting lugs and Inspection hole with cover should also be provided. Oil conservators shall be mounted on bracket attached to the top cover on tank. Dimension of the conservator shall be such as to allow change in volume of oil due to change in temperature from 10 C to 95 C.

WINDING AND INSULATION Winding shall be three phase with minimum class 'A' insulation High conductivity electrolytic quality copper shall be used for winding. Winding shall be suitably braced to with stand the dynamic forces due to short circuit and should be capable of bear the high voltage surges. Winding insulation shall be uniform and winding shall have full insulation. INSULATION OIL Insulation oil shall conform to IS-335. Transformer shall be supplied with initial fill of filtered oil.

Explosion Vent: Explosion vent or pressure relief device shall be provided of sufficient size for rapid release of any pressure that may generated with the tank and which might result in damage to the equipment. The device shall operate at a static pressure less than the hydraulic test pressure for transformer tank. Means shall be provided to prevent the ingress of moisture and of such a design to prevent accumulation. Rating and diagram plates: The following plates shall be fixed to transformer tank in a visible position. a. A rating plate of whether proof material bearing the data specified in the appropriate clauses IS 2026-1977. b. A diagram plate showing the internal connections and also the voltage vector relationship of the several winding in accordance with IS: 2026-1977 and a plan view of the transformer giving the correct physical relationship of the terminals. Joints and Gaskets All gaskets used for making oil tight joints be of proven material such as granulated cork bonded with synthetic rubber gasket or synthetic rubber so as to be totally weather proof.

REMCO (BID ID -3279880)