Cbip transformer manual free download.Download Cbip Manual On Transformer (publication No 295)

Looking for:

- (PDF) CBIP Tranformer Manual -  

Click here to DOWNLOAD

   

 

Cbip transformer manual free download -

 

Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Uploaded by uvilas. Did you find this document useful? Is this content inappropriate? Report this Document. Flag for inappropriate content. Download now. Jump to Page. Search inside document. Mathur R. The publishers have taken utmost care to avoid errors in the publication, However, the publishers are in no way responsible for the authenticity af data or information given by the contributor Central Board of Irrigation and Power Malcha Marg.

Goswami AGM Enge. Power Grid Corp, of India Ltd. Katakwar Superiniending Engineer Dist. Ballabhgarh, Haryana Shri K. K, Bhatia Adal. Majumdar Dy. Tiwari act Bharat Heavy Electricals Lad. Jhansi Shri C. Bhopal Shri R. Mohapatt Deputy General Manager. Jhansi Shri B. Bhopal Shri RK. Agrawal Bharat Heavy Flectrivals 14d. Bhopal Shri M.

Mumbai Shri A. Mumbai Shri M. Kapor ED Retd. Power Grid Corp. Since then we have made rapid "progress and on date this figure stands at 1,23, MW.

Matching with the generating capacity, transmission and distribution networks have also grown. Due to these shortages, despite best efforts the voltage and frequency in different grids sometimes varies beyond acceptable limits and lead to power cuts.

Transformer is a vital link for taking power supply from generating station to consumer premises. Matching with the growth in power sector, about 56, MVA power transformers and 26, MVA tansformers for distribution network in the country are being manufactured annually.

In transmission and distribution sector, cost of the power transformer represents the largest portion of the capital investment and financial consequences of failure of transformer lead to considerable loss of revenue besides break down of power supply. Ln early 70s, it was felt that industry should have detailed reference specifications for transformers.

This manual was subsequently revised in and in The transformer manual issued by CBIP is being widely used by power engineers as a reference book covering all aspects of transformers for almost all applications. Almost all the utilities in the country are referring the CBIP Manual on Transformers while formulating their own purchase specifications on the basis of technical information contained there in. Tam happy to note that this manual has been revised and updated now with the help of Working Group experts from all eminent organizations, and contains the latest technological information including installation, testing, commissioning and repairs of transformers besides additional chapters on kV transformers, Condition Monitoring and Diagnostic Techniques and chapters on various components of the transformers of all sizes and voltages including dry type transformers.

I congratulate CBIP and all experts of the Working Group for bringing out this manual covering latest state-of-art technology and am sure that this document will be of great use to engineering fraternity as a reference book.

In our country the transformers are subjected to severe stress condition due to wide variation in voltage and frequency in system due to huge gap in demand and supply causing higher failure rate of transformers as compared to western countries.

With the escalations in the cost of material and other inputs into its manufacture, the requirement of un-interrupted power and above all the steep rise in the cost of power has forced the manufacturers to compete in innovations and improvise designs as well as manufacturing practices to deliver a low-loss, competitive costing transformers with built-in monitoring features to ensure its long trouble- free service life.

On the other hand power utilities are also under immense pressure to maintain and upgrade their system to meet the rising demand in power with no tolerance for any breakdown in supply.

In line with our quality policy, to promote and coordinate professional excellence in water and power sector CBIP has prepared more than Manuals on all important subjects. To disseminate the latest developments among the engineer's fraternity, CBIP has updated these manuals from time to time.

This trend of repair of transformer at site is becoming popular since it saves in to and fro transportation time as well as HV test cost since some of the tests including HV Test are not to be repeated. I thank all experts of the working group for their valuable contribution. Tam sure that this Manual shall be of immense value and provide good reference document to the practising engineers especially those looking after planning, procurement, design, maintenance, testing and commissioning of power systems including transformers.

All apparatus shall also be designed to ensure satisfactory operation under such sudden variations of load and vollage as may be met with under working conditions on the system, including those due to short circuits. All material used shall be of the best quality and of the class most suitable for working under the conditions specified and shall withstand the variations of temperatures and amospheric conditions arising under working conditions without undue distortion or doterioration or the setting up of undue stresses in any part, and also without alfecting the strength and suitability of the various paris for the work which they have to perform 1.

Lock nuts shall be used on stud connections carrying current. All leads from the winding to the terminal board and bushings shall be adequately supported to prevent injury from vibration including a systematical pull under short circuit conditions. Guide pulls shall be used where practicable. The water extraction per tonne of insulation per hour may be limited to Si grams maximum.

Alternatively dryness can be judged by dew point measurement 1. The zinc coating shall be smooth, clean and of uniform thickness and free from defects. The preparation of galvanising and the galvanising itself shall not adverscly affect the mechanical properties of the coated material.

The quality will be established by tests as per IS: Alternative to galvanising, zinc spraying or aluminising can also be considered. The preparation for galvanising itself shall not adversely affect the mechanical properties of the wire.

Danger notices shall have red lettering on a white background 1. Only one thin layer 'S microns of this is to be applied. The type and thickness of paint shall be chosen to suit pollution level at site. For urban of industrial situation two coats of epoxy zinc phosphate or zine chromate primer topped with two coats of aliphatic polyurethane glossy finish paint is recommended.

If heaters are not provided in the chamber, then the top coat should be of aati condensation type. This is to be done by thoroughly cleaning the damaged area and applying the full number of coats as was applied originally. Manufacturer should supply the necessary paint for this touch up painting al site, 1. Supplicr shall furnish necessary information on the make and grade of the top-coat paint, In general, it is possible to apply cnamel paint over epoxy polyurethane coating and the vice versa is not recommended.

AS far as possible the make aid grade of the recoat shall be same as the original coat. The oil shall conform to IS : , Alternatively, if the purchaser so desires, oil may be supplied in tankers directly from the refinery for transformers which are despatched from factory to site in gas filled condition, 18 Prevention of Acidity L8.

Special measures, such as nitrogen sealing ot the use of inhibited oil shall not be resorted to, unless otherwise specified by the purchaser.

Where sealed transformers are specified, there shall be no conservator but adequate space shall be provided for expansion of oil without developing undue pressure. The types of cooling shall be as stated in the relevant specifications.

General oo Zon buidouy poi? Continuous Maximum Rating and Overloads 2. In case bi-directional flow of power is required, that shall be specifically stated by the purchaser. Temperature rise test shall be performed at the tapping as desired by the purchaser. Lf nothing has been stated by the purchaser, the test shall be carried out at the tapping with the highest load losses.

Two lcads from one open corner of the delta connection shall be brought out to separate bushings. Links shall. Any transformer may be directly connected to an underground or overhead transmission line and switched into and out of service together with its associated transmission line.

However, the purchaser will install the over fluxing protection device in case of generator step-up transformers : Note : All inter-connected transformers of SOMVA. The design of stabilising winding shall be such as to take care of the effect of transferred surges and the tenderer shall offer suitable surge protection wherever necessary.

The accepted losses of cach transformer shall be stated in the order. The tolerance on the losses of each transformer shall be in accordance with IS : Any specific eequirement may be mentioned at the time of enquiry as a prequalification instead of af the time of order. Every care shall be excercised in the selection, treatment and handling of core steel to ensure that as far as is practicable, the laminations are flat and the finally assembled.

However, laminations can be insulated by the manufactures if considered necessary 3. The winding structure and major insulation stall not obstruct the free flow of oil through such ducts Where the magnetic circuit is divided into pockets by cooling ducts parallel to the planes of the Iaminations or by insulating material above 0. The manufacturer shall state the overfluxing capability and corresponding withstand durations for the transformers for factors 1. Any non-magnetic or high resistance alloy shall be of established quality.

Adequate lifting lugs shall be provided to enable the core and windings to be lifted. All windings for system voltages lower than 66 kV shall be fully insulated. All neutral points shall be insulated for the voltages specified in IS : Power transformers shall be designed to withstand the impulse and power frequency test voltages as specified in IS : Adjustable devices shall be provided for taking up any possible shrinkage of coils in service.

Bracing of Windings 4. The windings and connections of all transformers shall be braced to withstand shocks: which may occur during transport, or duc to switching short-circuit and other transient conditions during service 4.

Coil clamping rings, if provided, shall be of steel or of suitable insulating material. Earthing of Core Clamping Structure 5. Farthing of Magnetic Circuit 5. The connection to the link shall be on the same side of the core as the main earth connection.

Connections inserted between laminations of different sections of core as per clause 5. Inspection covers shall always be bolted type. Altcmatively an equalising connection may be provided between the inside of air cell and conservator for evacuating the conservator along with air cell, which may be removed after evacuation and oil filling. The main tank body excluding tap-changing compartments, radiators and coolers shall be capable of withstanding vacuum given in the following table : Vacuum Highest syst MVA rating gauge um of Fz voltage KY pressure kN?

LS Normally a detachable underbase will be used, but in case transport facilities permit, a fixed underbase can be used, 6. Where packets cannot be avoided, pipes shall be provided to vent the gas into the main expansion pipe, The vent pipes shall have minimum inside diameter of 15 mm except for short branch pipes which may be 6 mm minimum inside diameter.

All bolted joints to the tank shall be fitted with suitable oilHight gaskets which shall give a satisfactory service under the operating conditions and guaranteed temperature tise conditions. Special attention shall be given to the methods of making hot oil tight joints between the tank and the cover as also between the cover and the bushing and all other outlets to ensure that the joints can be remade satisfactorily at site and with case with the help of semi-skilled labour.

The minimum height of the lugs above the base shall be: - Transformers upto and including 10 tonnes weight - mm approx. Each inspection opening shall be of ample size for the purpose for which it is provided and at least two openings one at cach end of the tank, shall he provided 6.

Protection shall be provided, where necessary, for each capillary tube. If required only one set of roller of each size to be asked for. They shall be of such dimensions and so supported that under any service conditions they shall not deflect sufficiently to interfere with the movement of the transformer. Suitable locking arrangements will be provided to prevent the accidential movement of the transformer.

Means shall be provided for locking the swivel movements in positions parallel to and at right angles to the longitudinal axis of the tank, 6S Conservator Vessels, Oil Gauges and Breathers 6. The minimum indicated oil level shall be with the feed pipe from the main tank covered with not less than 15 mm depth of oil and the indicated range of oil level shall be from minimum to maximum.

If the sump is formed by extending the feed pipe inside the conservator vessel, this extension shall be for at least 25 mm, The conservator shall be designed so that it can be completely drained by means of the drain valve provided, when mounted as in service.

The moisture absorption indicated by a change in colour of the tinted erystals, can be easily observed from distance. All breathers shall be mounted at approximately 1, mm above ground level. For diameter up to mm: Size of the valve 5 mm. For diameter above mm ; Size of the valve 25 mm. A robust oil sampling device shall be provided at the top and bottom of the main tank, The sampling device shall not be fitted on the filter valves specified under a above. One 15 mm release plug. For transformers above MVA rating, one mm bore valve shall be provided for attaching vacuum connection and with provisions for attaching a vacuum gauge, a pressure gauge or an oil level indicator.

Allother valves opening to atmosphere shall be fitted with blank flanges. Cooler and Radiator Connections. Valves and valve mountings shall be provided as specified under "Cooling Plant" Clause 7 All valves shall be of gun-metal or cast steel or may have cast iron bodies with gun- metal fittings.

This is required for the valves where opening device like hand-wheel, keys, etc. Every valve shall be provided with an indicator to show clearly the position of the valve. The drilling of valve flanges shall comply with the requirements of I 68 — Pressure Relief Device 6. The breather being mounted in a suitable position for access at ground level.

It shall be provided with a microswitch for actuating trip contact when it operates. It shall also give a visual indication of valve operation by raising a flag. The flag and the switch shall remain operated until they are reset manually. The operating pressure of the pressure relicf valve shall always be Jess than the tank test pressure, The microswitch shall have IP 55 protection and the fasteners shall be of rust proof material.

General 7 6. When links are provided in accordance with clause 2. No load voltage shall be indicated for each tap. This plate shall also warn operators to refer to the maintenance instructions before applying the vacuum weatment for drying Fig. Hevea package WN putaion ive! Inlet eit valve Outlet oi! Valves shall be provided on the tank at each point of connection to the tank, 7. The design of shell and tube assembly shall be such as to facilitate cleaning without any risk of water mixing with the oil.

The material of the tube plates and tube shall be such that corrosion shall not take place due to galvanic action. The water pressure in the cooler will be kept as low as possible, Further, the cooling water discharge should be free to the atmosphere to reduce the pressure in the cooler. The oil piping shall be with flanged gasketed joints. Cast iron shall nat be used.

It shall be possible to remove the pump and motor from the oil circuit without having to lower the level of oil in the transformer or coolers and without having to disturb the pump foundation fixing. Oil pump shall be capable of dealing with the maximum output of transformer and total head which may occur in service and with the varying head due to changes in the viscosity of the oil. The bearings shall be of sealed type, which docs not require frequent lubrication. Air blowers shall be capable of withstanding the stresses imposed when brought up to full speed by the direct application of full ine voltage to the motor.

In order to reduce the transmission of noise and vibration the blowers shall be either mounted independently from the coolers or, alternatively, an approved form of antivibration mounting shall be adopted. It shall be possible to remove the blower complete with motor without disturbing or dismantling the cooler structure framework. Guards shall be provided over all moving shaft and couplings. The motors shall be capable of operating at all loads without undue vibration and with a minimum of noise.

Weather-proof motors shall be provided with suitable means of breathing and drainage to prevent accumulation of water. All motor terminals shall be of the stud type and totally enclosed, 7. Additional terminals for remote manual electrical control of motors shall be provided. Overload and single phasing protection shall be provided but no-velt release shall not be fitted. HRC fuses shall be provided for the main supply. Alternative to galvanising, zinc spraying or aluminising can also be considered.

The preparation for galvanising itself shall not adversely affect the mechanical properties of the wire. A matt or satin finish shall be provided to avoid dazzle from reflected light. Labels mounted on dark surfaces shall have white lettering on a black background. Danger notices shall have red lettering on a while background. General 7 1. After cleaning, these surfaces should be immediately covered with paint. The type and thickness of paint shall be chosen to suit pollution level at site.

If heaters are not provided in the chamber, then the top coat should be of anti condensation type. This is to be done by thoroughly cleaning the damaged area and applying the full number of coats as was applied originally. Manufacturer should supply the necessary paint for this touch up painting at site. Supplier shall furnish necessary information on the make and grade of the lop-coat paint.

In general, it is possible to apply enamel paint over epoxy polyurethane coating and the vice versa is not recommended. As far as possible the make and grade of the recoat shall be same as the original coat. Alternatively, if the purchaser so desires, oil may be supplied in tankers directly from the refinery for transformers which are dispatched from factory to site in gas filled condition.

Special measures, such as nitrogen sealing or the use of inhibited oil shall not be resorted to, unless otherwise specified by the purchaser. Normally oil immersed transformer shall be provided with conservator vessels. Where sealed transformers are specified, there shall be no conservator but adequate space shall be provided for expansion of oil without developing undue pressure. The types of cooling shall be as stated in the relevant specifications.

General 9 2. The forced cooling equipment shall come into operation by pre-set contacts in WTI and the transformer will operate as a forced cooled unit. In case bi-directional flow of power is required, that shall be specifically stated by the purchaser. If nothing has been stated by the purchaser, the test shall be carried out at the tapping with the highest load losses.

Note: Operation of a transformer at rated kVA at reduced voltage may give rise to excessive tosses and temperature rise. Two leads from one open comer of the delta connection shall be brought out to separate bushings. Links shall be provided for joining together the two terminals so as to complete the delta connection and earthing it external to the tank. Any transformer may be directly connected to an underground or overhead transmission line and switched into and out of service together with its associated transmission line.

However, the purchaser will install the over fluxing protection device in case of generator stepup transformers. Note : All inter-connected Transformers of 50MVA and above shall also be provided with over fluxing protection by the purchaser. General 2. The tolerance on the losses of each transformer shall be in accordance with IS: , except where maximum losses are specified. Any specific requirement may be mentioned at the time of enquiry as a prequalification instead of at the time of order.

However, in case of transformers with variable flux the voltage variation which would affect flux density at every tap shall be kept in view while designing transformers. For medium rating transformers, the core may be constructed of similar to M4 or better grade cold rolled non-aging grain oriented silicon steel laminations.

The selection of Grade much depends upon loss capitalization formula Section AA for an optimized design and also upon stipulation in customer specification. However, laminations can be insulated by the manufactures if considered necessary. The winding structure and major insulation shall not obstruct the free flow of oil through such ducts. Where the magnetic circuit is divided into pockets by cooling ducts parallel to the planes of the laminations or by insulating material above 0.

Any non-magnetic or high resistance alloy shall be of established quality. All windings for system voltages lower than 66 kV shall be fully insulated. All neutral points shall be insulated for the voltages specified in IS: General 13 4. Adjustable devices shall be provided for taking up any possible shrinkage of coils in service. The bottom clamping structure shall be earthed by one or more of the following methods: a By connection through vertical tie-rods to the top structure b By a connection to the loop structure on the same side of the core as the main earth connection to the lank 14 5.

The connection to the link shall be on the same side of the core as the main earth connection. Transformers with bell type tank may have joint either at tank bottom or close to bottom of the tank.

Inspection covers shall always be bolted type. Alternatively an equalizing connection may be provided between the inside of air cell and conservator for evacuating the conservator along with air cell, which may be removed after evacuation and oil filling. Where pockets cannot be avoided, pipes shall be provided to vent the gas into the main expansion pipe. The vent pipes shall have a minimum inside diameter of 15 mm except for short branch pipes which may be 6 mm minimum inside diameter.

All bolted joints to the tank shall be fitted with suitable oil-tight gaskets which shall give a satisfactory service under the operating conditions and guaranteed temperature rise conditions. Special attention shall be given to the methods of making hot oil tight joints between the tank and the cover as also between the cover and the bushing and all other outlets to ensure that the joints can be remade satisfactorily at site and with ease with the help of semi-skilled labour.

Inspection openings shall be provided as necessary to give easy access to bushings or changing ratio or testing the earth connection. Each inspection opening shall be of ample size for the purpose for which it is provided and at least two openings one at each end of the tank, shall be provided. Unless otherwise approved inspection covers shall not weigh more than 25 kg each. Protection shall be provided, where necessary, for each capillary tube.

If required only one set of roller of each size to be asked for. They shall be of such dimensions and so supported that under any service conditions they shall not deflect sufficiently to interfere with the movement of the transformer. Suitable locking arrangements will be provided to prevent the accidental movement of the transformer.

The direction of withdrawal shall be specified. General 17 6. Means shall be provided for locking the swivel movements in positions parallel to and at right angles to the longitudinal axis of the tank. The minimum indicated oil level shall be with the feed pipe from the main tank covered with not less than 15 mm depth of oil and the indicated range of oil level shall be from minimum to maximum.

For The conservator shall be designed so that it can be completely drained by means of the drain valve provided, when mounted as in service. The color changes from orange to light yellow as it absorbs moisture.

For diameter up to mm: Size of the valve 15 mm. For diameter above mm: Size of the valve 25 mm. The sampling device shall not be fitted on the filler valves specified under a above.

Larger valves may be of gunmetal or may have cast iron bodies with gunmetal fittings. They shall be of full General 19 way type with internal screw and shall be opened by turning counter clock-wise when facing the handwheel. This is required for the valves where opening device like hand-wheel, keys, etc. PRD shall be of sufficient sizes for rapid release of any pressure that may be generated within the tank, and which might result in damage to the equipment.

The device shall operate at a static pressure of less than the hydraulic test pressure for transformer tank. Means shall be provided to prevent the ingress of rain water. The breather being mounted in a suitable position for access at ground level. It shall be provided with a micro switch for actuating trip contact when it operates. It shall also give a visual indication of valve operation by raising a flag. The flag and the switch shall remain operated until they are reset manually.

The operating pressure of the pressure relief valve shall always be less than the tank test pressure. The micro switch shall have IP 55 protection and the fasteners shall be of rust proof material. This is to avoid injury to personnel in event of PRD operation and subsequent splashing of oil. Short circuit current of the transformer. Provision shall be made at positions close to each of the bottom two corners of the tank for bolting the earthing terminals to the tank structure to suit local conditions.

When links are provided in accordance with clause 2. No load voltage shall be indicated for each tap. A warning plate shall also be provided for OCTC operation during de-energized condition only. This plate shall also warn operators to refer to the maintenance instructions before applying the vacuum treatment for drying Fig.

General 21 22 Manual on Transformers General 23 Fig. The design of shell and tube assembly shall be such as to facilitate cleaning without any risk of water mixing with the oil. The material of the tube plates and tube shall be such that corrosion shall not take place due to galvanic action.

A water analysis report shall be furnished, in time, to enable supplier to ensure a suitable material for tube and tube plates. The water pressure in the cooler will be kept as low as possible. Further, the cooling water discharge should be free to the atmosphere to reduce the pressure in the cooler. Provision for leakage detector system shall be provided along with alarm contacts for water coolers. The oil piping shall be with flanged gasket joints. Cast iron shall not be used. It shall be possible to remove the pump and motor from the oil circuit without having to lower the level of oil in the transformer or coolers and without having to disturb the pump foundation fixing.

Oil pump shall be capable of dealing with the maximum output of transformer and total head which may occur in service and with the varying head due to changes in the viscosity of the oil. They shall be suitable for continuous operation outdoors and capable of dealing with the maximum output and total head required in service.

The bearings shall be of sealed type, which does not require frequent lubrication. In order to reduce the transmission of noise and vibration the blowers shall be either mounted independently from the coolers or, alternatively, an approved form of antivibration mounting shall be adopted.

It shall be possible to remove the blower complete with motor without disturbing or dismantling the cooler structure framework. Fans mounted at more than 2. Guards shall be provided over all moving shaft and couplings. General 7. The motors shall be capable of operating at all loads without undue vibration and with a minimum of noise. They shall be suitable for direct starting and for continuous running from volts three-phase, 4 wire 50 Hz supply. Motors upon which the primary equipment depends for its continued operation at full load shall also be capable of continuous operation at 85 percent of the nominal voltage at normal frequency without injurious over-heating.

Weather-proof motors shall be provided with suitable means of breathing and drainage to prevent accumulation of water. All motor terminals shall be of the stud type and totally enclosed.

Additional terminals for remote manual electrical control of motors shall be provided. Overload and single phasing protection shall be provided but no-volt release shall not be fitted. This equipment shall be accommodated in the marshalling box specified in clause The motor contactors and associated apparatus shall be capable of normal operation with a supply voltage of 85 per cent of the normal value and at normal frequency. In case the transformer is switched off for a longer time, the oil pump can also be switched off but it shall be ran at least one hour earlier before the transformer is energised again.

The over voltage power frequency test level or the BIL of bushings should be one step higher than that of the windings. Where accommodation for current transformers is required on Clamps and fittings made of steel or malleable iron shall be hot dip galvanised.

All fasteners of size 12 mm and above shall be hot dip galvanised and fasteners of size less than 12 mm shall be of stainless steel. The take off point of the vent pipes shall be the top most point on the bushing turret so that there will not be any air trapped in the -bushing turret. Note: 1 These clearances are applicable for transformers to be installed up to an altitude of m above mean sea level.

Bushings of rating below 52 kV may be solid porcelain or oil communicating type. However it has to be specified by the user. They shall also be provided with expansion chambers for the filling medium and means of preventing the formation of air spaces when filling. Drain plugs of ample size shall be provided to enable the filling medium to be removed quickly.

The ends of all wiping glands shall be tinned before dispatch to site. Wiping glands for single core cables shall be insulated from the box. Wiping glands insulation cables shall be capable of withstanding a dry high voltage test of 2, volts AC for one minute.

Air insulated cable boxes for PVC cables may be provided with compression glands. Sufficient wiping glands shall be provided for the termination of required number of cables. Where there is more than one core per phase, the socket block shall be so designed as to minimize bending of the cable cores.

A barrier shall be provided on both sides of the disconnecting chamber to prevent ingress of the oil used for filling the chamber into the cable box or the transformer. It shall only be necessary to remove part of the oil in the chamber itself when making the necessary testing connections. A barrier shall then be provided between the sealing end chamber and the main tank subject to the provision of the next paragraph.

Insulating Fire resistant barriers should be provided between each phase of HV cable box. In case of compound filled cable box with shrinkable tape, the allowable minimum clearances shall be subject to the agreement between manufacturer and the user.

However, filling medium will be supplied as a part of the cable box by the manufacturer. The device shall have a dial type indicator and in addition a pointer to register the highest temperature reached. The number of contacts as specified will be provided. If specified, for transformers above 10 MVA a remote repeater indicator electrically operated from winding temperature indicator is to be provided for mounting General 33 on the control panels.

Unless otherwise specified the remote repeater indicator shall be of flush mounting type. Micro switches shall be preferred to mercury switches. Connections shall be brought from the device to terminals placed inside the marshalling The oil circuit through the relay shall not form a delivery path in parallel with any circulating oil pipe, nor shall it be tied into or connected through the pressure relief vent.

Sharp bends in the pipework shall be avoided. The box shall have domed or sloping roofs and the interior and exterior painting shall be in accordance with clause 1. For illumination, a suitable lamp or CFL shall be provided whose switching shall be controlled by the door switch. General 35 The gland plate and associated compartment shall be sealed in suitable manner to prevent the ingress of moisture. Any wiring liable to be in contact with oil shall have oil resisting insulation and the bared ends of stranded wire shall be sweated together to prevent creepage of oil along with wire.

All instruments and panel wiring shall be run in PVC or non-rusting metal cleats of the limited compression type. All wiring to a panel shall be taken from suitable terminal boards.

All conduit runs shall be adequately drained and ventilated. Conduits shall not be run at or below ground level. All wiring shall be of stranded copper of V grade and size not less than 4.

The change of numbering shall be shown on the appropriate diagram of the equipment. They shall be clearly and durably marked and shall not be affected by damp or oil. Separate washers shall be used for each wire. The size of the washer shall be suited to the size of the wire terminated. Wiring shall in general be accommodated on the sides of the box and the wires for each circuit shall be separately grouped. Back of panel wiring shall be arranged so that access to the connecting stems of relays and other apparatus is not impeded.

The function of each circuit shall be marked on the associated terminals boards. All diagrams shall show which view is employed. The position of the earthing connections shall be shown clearly on the diagrams. Terminal boards shall have pairs of terminals for incoming and outgoing wires.

Insulating barriers shall be provided between adjacent connections. The height of the barriers and the spacing between terminals shall be such as to give adequate protection while allowing easy access to terminals. The terminals shall be adequately protected with insulating dust-proof covers. One dummy terminal block in between each trip wire terminal shall be provided. No Loop in Loop out shall be adopted for power circuit. Box to avoid any hazard due to loose connection leading to CT opening or any other loose connection.

Terminal block shall preferably be stud type suitable for ring O type lugs. Four copies of test certificates will be supplied. Furnishing test certificates from the original equipment manufacturer works shall be deemed to be satisfactory evidence. Inspection of tests at the sub-contractors works will be arranged by the supplier wherever required.

The pressure shall be maintained for a period of minimum one hour during which time no leakage shall occur. The equivalent air pressure corresponding to oil pressure calculated at the base of the tank to be considered for air pressure test.

Permanent deflection of flat plates shall be measured on one tank of each design, if specified by customer, after the excess pressure has been released and shall not exceed the figures specified below: Horizontal length of flat plate total length of tank wall in mm Up to and including to to to to to to Above a2 Permanent deflection in mm 5 6.

The pressure shall be maintained for a period of one hour during which time no leakage shall occur. The pressure to be maintained for eight hours during which time no leakage shall occur. The tanks designed for full vacuum mm of mercury at sea level or the barometric reading at the location of test shall be tested at a maximum internal pressure of 3.

The permanent deflection of flat plates after vacuum has been released shall not exceed the values specified in clause General 39 A list of standards for transformers is given in Appendix II.

A list of transformeraccessories and routine test certificate required for them is given. The design review shall be finalized before commencement of manufacturing activity. C iii Min. C iv Max average daily ambient air temperature deg. C v Max. C vi Max. The transformer shall conform to the following specific parameters: SL. No Item 1. Minimum clearances in The complete design of core must ensure permanency of the core losses with continuous working of the transformers.

The value of the maximum flux density allowed in the design and grade of lamination used shall be clearly stated in the offer. The manufacturer should offer the core for inspection and approval by the purchaser during manufacturing stage. MS Channels shall be painted with varnish or oil-resistant paint. MS core clamps shall be painted with varnish or oil-resistant paint. MS rods shall be used as tie rods. The Manufacturer shall furnish necessary design data in support of this situation.

Increase of voltage of volts by The complete design of core must ensure permanency of the core loss with continuous working of the transformers. The value of the flux density allowed in the design shall be clearly stated in the offer. Curve showing the properties of the metal shall be attached with the offer. Aluminium conductors can also be used with same loss levels as of copper wound transformers.

Dimensional tolerances for winding coils shall be with in limits as specified in GTP. In case of cross-over coil winding of HV all spacers shall be properly sheared and dovetail punched to ensure proper locking.

Insulation shearing, cutting, milling and punching operations shall be carried out in such a way, that there is no burr or dimensional variations. The above losses eventually may get revised if any, after said revision. The above losses are maximum allowable and there would not be any positive tolerance. Transformers with higher losses than the above specified values would be treated as Nonresponsive. Transformers with losses less than those specified above will be capitalized during transformer evaluation as indicated below.

Iron Losses - Rs. Copper Losses - Rs. No Price Component 1. Unit ex-works price 2. Sales Tax 5. NLL 7. Cost of Total NLL 6 x 7 9. LL Costoftotal LL 9x 10 Type test charges C shall be 4. C shall not exceed the limits given below: Top oil temperature rise measured by thermometer Winding temperature rise measured by resistance : 35 Deg. C : 40 Deg. C Transformers not meeting the above limits of temperature rise shall not be accepted. For fraction of a kW, proportionate penalty will be recovered.

The delivery as per contract will be counted when the new transformer as per specification is provided by the manufacture. The internal clearance of tank shall be such that, it shall facilitate easy lifting of core with coils from the tank without dismantling LV bushings. All joints of tank and fittings shall be oil tight and no bulging should occur during service.

The tank design shall be such that the core and windings can be lifted freely. The tank plate shall be of such strength that the complete transformers when filled with oil may be lifted bodily by means of lifting lugs.

The four walls of the tank shall be made of Two "L" shaped sheets without joints fully welded at the corners from inside and outside of the tank for withstanding a pressure of 0. The tank shall be reinforced by angle welded on all the outside walls on the edge of the tank to form two equal compartments.

Permanent deflection when the tank without oil is subject to a vacuum of mm of mercury for octogonal tank and mm of mercury for round tank, shall not be more than 5 mm upto mm length and 6. The tank shall further be capable of withstanding a pressure of 0. The radiators can be tube type or fin type or pressed steel type to achieve the desired cooling and the same shall be capable of giving continuous rated output without exceeding the specified temperature rise.

Top cover fixing bolts of Galvanised Iron adequately spaced and 6 mm Neoprene bonded cork gaskets conforming to IS part-II shall be placed between tank and cover.

The bolts outside tank shall have 2 flat washers and one spring washer. The transformer tank shall be of robust construction corrugation in shape and shall be built up of CRCA sheets of 1. Corrugation panel shall be used for cooling. The transformer shall be capable of giving continuous rated output without exceeding the specified temperature rise. Tanks with corrugations and without conservator shall be tested for leakage test at a pressure of 0.

Space is provided above the core coil assembly where inert gas cushion system accommodates the oil expansion under variable pressure. The tank should be of stiff construction able to withstand pressure of 2 atmospheres. For other ratings manufacturer may adopt their standard practice. Conservator is not required in transformers with corrugated tank. When a conservator is provided, oil gauge and the plain or dehydrating breathing devise shall be fixed to the conservator which shall also be provided with a drain plug and a filling hole M30 normal size thread with cover.

The capacity of a conservator tank shall be designed keeping in view the total quantity of oil and its contraction and expansion due to temperature variations. In addition the cover of main tank shall be provided with an air release plug to enable air trapped within to be released, unless the conservator is so located as to eliminate the possibility of air being trapped within the main tank.

The inside diameter of the pipe connecting the conservator to the main tank should be within20 to 50 mm and it should be projected into the conservator so that its end is approximately 20 mm above the bottom of the conservator so as to create a sump for collection of impurities. The minimum oil level corresponding to -5 deg C should be above the sump level. The bushings shall be fixed to the transformers on side with straight pockets and in the same plane or on the top cover.

Arcing horns or lightning arrestors shall be provided on HV bushings. For 11 kV, Bushings with plain sheds as per IS shall be mounted on the side of the Tank and not on top cover.

A minimum phase to phase clearance of 75 mm for LV upto 1. The terminal arrangement shall not require a separate oil chamber not connected to oil in the main tank. Connectors shall be with eye bolts so as to receive 55 sq mm conductor for HV. The neutral point terminal shall be indicated by the letter 2N. Neutral terminal to be brought out and connected to local grounding terminal by an Earthing strip.

Current transformer shall be mounted inside the tank on LV side of the transformer. All secondary leads of bushing mounted CT's shall be brought to a terminal box near each bushing. The CT terminals shall have shorting facility. The metal oxide lightning arresters shall be of reputed make.

This fuse is mounted normally inside of the primary bushing for the three phases and is connected to the high voltage winding through a terminal block. This has to protect that part of the electrical distribution system which is ahead of the distribution transformers from faults which occur inside the distribution transformer i. It shall be ensured that this fuse does not blow for faults on the secondary side LT side of the transformer i.

As such it shall be designed for perfect coordination with the HT fuse link. The two characteristics shall be drawn on the same sheet to indicate coordination between the circuit breaker and fuse.

The Manufacturer shall carry out coordination test as indicated above and this forms one of the tests for acceptance test. The breaker shall be coordinated thermally with the transformer design to follow closely the variations of coil temperature due to fluctuating loads and ambient temperatures.

This is to be accomplished by connecting the breaker in series between the secondary winding and the secondary bushings. The breaker shall be located in the same oil as the core and coil assembly so that the bimetal are sensitive to the temperature of oil as well as the load current The circuit breaker shall also be closed and opened manually standing on ground. The current carrying parts of breakers shall be copper plus a set of copper tungsten current interrupting contacts. The cross-section of the current carrying parts of the breaker shall withstand the full load current at a current density not more than 2.

All plastic material shall comply to glow wire test as per relevant IS. Type test report from NABL accredited laboratory shall be submitted. A distribution box made of MS or SMC or FRP shall be provided as an integral part of the transformer to be mounted on the tank before installation on the pole. LT bushing shall be inside the distribution box and a facility for sufficient number of outgoing feeders through cable glands shall be provided.

Distribution box shall also have provision for installation of energy meter. Distribution box shall be designed for out-door duty with minimum IP - 55 protection. It shall have pad-locking arrangement.

It shall forewarn any overloading problem at the installation such that a change out of the existing transformer with a higher capacity transformer can be planned. The signal light mechanism shall not reset itself when the load drops from the overloaded condition. The signal light shall remain lighted once the signal light contacts close due to overload and can be turned off by manual operation.

The signal light shall not give indication for momentary overloading. Base channel 75 x 40 mm MCCB or Oil immersed LT circuit breaker along with operating rod HV fuse links Signal light Fasteners All bolts, studs, screw threads, pipe threads, bolt heads and nuts shall comply with the appropriate Indian Standards for metric threads, or the technical equivalent. Specifications for Outdoor type, Completely Self Protected, 3 Phase Distribution Transformers upto and including kVA 55 Bolts or studs shall not be less than 6 mm in diameter except when used for small wiring terminals.

All nuts and pins shall be adequately locked. Wherever possible bolts shall be fitted in such a manner that in the event of failure of locking resulting in the nuts working loose and falling off, the bolt will remain in position.

Appropriate precautions shall be taken to prevent electrolytic action between dissimilar metals. Each bolt or stud shall project at least one thread but not more than three threads through the nut, except when otherwise approved for terminal board studs or relay stems. If bolts nuts are placed so that they are inaccessible by means of ordinary spanners, special spanners shall be provided. Taper washers shall be provided wherever necessary. Load loss at rated current and normal frequency Impedance voltage test Resistance of windings Induced over voltage withstand test.

Separate source voltage withstand test. LT Circuit Breaker coordination test. Air pressure test on assembled transformer at 0. Impulse voltage test: As per clause no. BIL for 11 kV shall be 95 kV peak. Short circuit test. The tank designed for vacuum shall be tested at an internal pressure of 0. The permanent deflection of tie flat plates after the excess pressure has been released, shall not exceed the figures for vacuum test.

It shall operate before reaching the test pressure as specified in the above clause. The operating pressure shall be recorded. The device shall seal-off after the excess pressure has been released. Oil samples one sample per lot to comply with IS Single phase LV excitation current at all three phases for reference 6.

Temperature rise test. Lightning impulse withstand voltage test: Oil samples before and after short-circuit and temperatures rise test for each tested transformer.

For general requirements and tests, reference shall be made to sections A to BB of the Manual. International Standards tabulated above. C Min. C Max. The transformer shall conform to the following specific parameters.

Rated Voltage I. No of phases Single Single Single Single 8. Tap changing arrangement Not provided Not provided Not provided Not provided The secondary winding shall be connected to two LV bushings. Air gap in the core assembly shall be avoided.

Amorphous metal core shall be annealed under magnetic field. The transformer shall be suitable for over fluxing due to combined effect of voltage and frequency upto The operating flux density shall be such that there is a clear safe margin over the overfluxing limit of The inter layer insulation shall consist of epoxy resin coated paper or epoxy resin dotted paper.

The windings shall be progressively wound in LV - HV coil design for better voltage regulation and mechanical strength. Compression bonding of the windings shall be ensured by deploying suitable press in the winding process or by curing of epoxy paper insulation in a suitable press. The core coil assembly shall be dried in an oven. The type of winding shall be indicated, whether LV windings are of conventional to type or foil wound. Joints in the winding shall be avoided. Oil 5. Use of recycled oil is not acceptable.

Oil filling shall be carried under vacuum of 5 torrMin. Transformers with higher losses than the above specified values would be rejected. Transformers with losses less than those specified above will be capitalized during bid evaluation as per loss capitalization formula as given below.

Loss Capitalization factors: A. Price schedule: The following format shall be filled by the manufacturer for evaluating TOC. LL Watts Cost of total LL 9 x 10 Rupees For fraction of a Watt, proportionate penalty will be recovered. The delivery as per contract will be counted when the manufacturer provides the new transformer as per specification. There must be sufficient space from the core to the top cover to take care of oil expansion. The tank cover shall have plasticised surface at the top to guard against bird faults.

Alternately, suitable insulating shrouds shall be provided on the bushing terminals. The circular base plate edges of the tank should be folded upward, for at least 25 mm, to have sufficient overlap with vertical sidewall of the transformer.

Tank shall have permanent lugs for lifting the transformer bodily and there shall be facilities for lifting the core coil assembly separately. The transformer tank and the top cover shall be designed in such a manner as to leave no external pockets in which water can lodge. The transformer shall be provided with two mounting lugs suitable for fixing the transformer to a single pole by means of 2 bolts of 20 mm diameter as per ANSI C HV bushing pocket shall be embossed to top side of the top cover so as to eliminate ingressing of moisture and water.

Tank sealing - The transformer shall be of sealed tank construction with welded or bolted cover which seals the interior of the tank from atmosphere and in which gas volume plus oil volume remains constant.

The space on the top of the oil shall be filled with dry air or nitrogen. The nitrogen plus oil volume inside the tank shall be such that even under extreme operating conditions, the pressure generated inside the tank does not exceed 0.

The nitrogen shall conform to commercial grade of the relevant Standard. Terminal connectors must comply as per IS : The HV bushings shall be fixed to the top cover of the transformer and the LV bushings shall be fixed to transformer on sides and in the same plane.

The bushing rods and nuts shall be of brass. The HV bushings shall not have arcing horns. The HV winding terminals shall be marked 1. In case of 11 kV HV winding the terminal shall be marked as 1. The corresponding secondary terminal shall be marked as 2.

The fuse on primary side of the distribution transformer shall take care of any fault occurring inside the transformer itself. The characteristic of the fuse and LT breaker shall be well coordinated so that the fuse shall not blow for any faults on the secondary side of the transformer beyond LT Breaker and those faults shall be cleared by LT breaker only. The fuse shall confirm to IS and shall be tested for short circuit current. As such it shall be designed for perfect coordination with the HT fuse for various current multiples.

The two characteristics shall be drawn on the same sheet to indicate coordination between the circuit breaker and HV fuse. The manufacturer shall carry out coordination test as indicated above, and this forms one of the tests for acceptance. The LT breaker shall also be coordinated with overload characteristics of the transformer. The reference temperature for calibration shall be 40 Deg C.

Arrangement shall be made so that the circuit breaker can be closed and opened manually standing on ground. The cross section of the current carrying parts of the breaker shall withstand the full load current at a current density not more than 2.

Rated short circuit breaking capacity of the breaker shall not be less than 2. The circuit breaker shall confirm to IS with power factor 0. Manufacturer shall offer either internally mounted oil immersed circuit breaker or MCCB as specified below. Utilities may specify any one option. The Earthing terminal of the lightning arresters shall be connected 68 Manual on Transformers solidly to the Earthing terminal on the tank body.

Lightning arrestors with polymer insulators in line with relevant IEC shall also be acceptable. The PRD shall be provided in the lowvoltage terminating portion of the tank above top oil level. Inlet port shall be V4 inch or longer NPT.

Resealing pressure shall be 0. Bolts or studs shall not be less than 6 mm in diameter except when used for small wiring terminals. Taper washers shall be provided where necessary. Oil samples before and after short circuit and temperature rise test. For general requirements and tests, reference shall be made to sections A and BB respectively of the Manual.

Max average daily ambient air temperature Deg. However no. Preference shall be given for off-circuit tap link arrangement. Tap change arrangement is not preferred in an ideal case. Switch position No. Each tap change shall result in variation of 2. Provision shall be made for locking the tap changing switch handle in position. LVStar Vector Symbol Dyn11 8. Note: 1. Proper bonding of inner layer insulation with the conductor shall be ensured.

C 40 Deg. The internal clearance of tank shall be such that it shall facilitate easy lifting of core with coils from the tank without dismantling LV bushings.

The tank shall be reinforced by welded angle on all the outside walls on the edge of the tank to form two equal compartments. Permanent deflection when the tank without oil is subject to a vacuum of mm of mercury for rectangular tank and mm of mercury for round tank shall not be more than 5 mm upto mm length and 6 mm upto mm length. Top cover fixing shall be with galvanised iron bolts and 6 mm Synthetic resin bonded cork sheet gasket type RC 70C conforming to IS part-II shall be placed between tank and cover.

Corrugated panel shall be used for cooling. The tank should be of stiff construction, able to withstand pressure of 2 atmospheres. Conservator is not required for corrugated tanks. When a conservator is provided, oil gauge and the plain or dehy drating breathing devise shall be fixed to the conservator, which shall also be provided with a drain plug and a filling hole M30 normal size thread with cover.

In addition, the cover of main tank shall be provided with an air release plug to enable air trapped within to be released, unless the conservator is so located as to eliminate the possibility of air being trapped within the main tank. The inside diameter of the pipe, connecting the conservator to the main tank, should be within 20 to 50 mm and it should be projected into the conservator so that its end is approximately 20 mm above the bottom of the conservator so as to create a sump forcollection of impurities.

The minimum oil level corresponding to -5 deg. For 1. Bushings in HV cable box as per BS may be used for compound filled cable box or termination in air with boots covering the live terminals. All other tests as per relevant standards shall be applicable. Specifications for Three Phase Distribution Transformers above kVA and upto 33 kV class 81 For outdoor bare bushings the LV and HV bushing stems shall be provided with suitable terminal connectors so as to connect the jumper without disturbing the bushing stem.

Two earthing terminals studs and bolts should be properly galvanized and conform to IS: and IS: It shall have 30 mm dia drain valve, oil filling hole with cap on the top of the conservator. One drain cum sampling valve One filter valve on upper side of tank. Fasteners Bolts or studs shall not be less than 6 mm in diameter except when used for small wiring terminals. If bolts, nuts are placed so that they are inaccessible by means of ordinary spanners, special spanners shall be provided.

This part specification does not purport to include all the necessary provisions of a contract. For other kV class transformers, this may be provided for higher ratings, if required.

In case of on-load tap changer, the tappings shall also be on the high voltage winding. When under this condition the high voltage side experiences Specifications for Power Transformers of Voltage Class below kV 87 an over-voltage, the tappings shall be changed so that the over-excitation is limited to 10 percent only.

Transformers shall be fitted either with bushing insulators or cable boxes as required by the purchaser. Cover lifting lugs. Lifting lugs. Skids and pulling eyes on both directions. Oil-filling hole and cap. Jacking pads. Pocket on tank cover for thermometer. Air release devices.

The same can be used for filtering purpose. Bottom Filter Valve. Switching of fans shall be done by winding temperature indicator for all transformers having ONAF rating.

The winding temperature indicator shall be provided with antivibration mounting. Tank mounted weather-proof marshalling box for housing control equipment and terminal connectors. If single phase units are required due to transport limitations, then these ratings will be one-third of the three-phase unit. Maximum yearly weighted average temp. Lifting bollards. Haulage lugs. The sampling valve shall be provided with provision for fixing PVC pipe. For transformer above 50 MVA, the remote indication shall be a separate measuring system.

Gauge s t u v Rating Type Shorter axis Longer axis 1. Two winding and auto transformers Flanged bi-directional with locking and bolting device. Generator transformers Flanged, bi-directional with locking and bolting device. Alternatively 4 rails in two pairs with mm gauge for each pair and centre distance between pair mm. Inspection cover. On-load tap changing gear with remote control panel as required.

Bottom valve to be used as drain valve also. LV—Star with neutral effectively earthed. No stabilizing winding up to MVA for 3-phase, 3 limbed core type construction. Alternatively star with neutral effectively earthed. Alternatively YNyno. Note : 1 In case auto-transformers are provided with L. The minimum rated lightning impulse withstand voltage level shall be kV peak.

Rated short duration power frequency voltage shall be 70 kV. LV — Delta. If single phase units are required due to transport limitations then these ratings will be one-third of the three-phase unit.

Each bank shall have one stand by fan and one stand by pump. The terminal bushings shall be as per Section II. Conservator with oil filling hole, cap drain valve. Magnetic type oil gauge with low oil level alarm contacts of 0. Silicagel breather with oil seal-2 Nos. Note: In addition to the silicagel breather more advanced oil preservation system like air dryers, molecular sieve flexible membrane can also be considered.

Rating Type Gauge Shorter axis 1 1. Generator Transformers Flanged bidirectional With locking and Bolting device. Longer axis 4 5 mm mm 2 rails with mm gauge 2 rails with mm gauge Alternatively 3 rails with mm gauge between adjacent rails. Repeater dial of winding temperature indicator for remote indication. On-load tap changing gear with remote control panels as required. Cooling accessories. The purchaser shall specify the type of cooling required. Wherever transport restrictions impose, single phase ratings equal to one-third of the three phase bank rating may be specified.

Rating under ONAF condition shall be about 80 per cent. No arcing horns shall be provided. For details refer Section II. Neutral End: The tap changers shall be suitable for bi-directional flow of rated power. The tap changers shall be in accordance with Section GG. Wherever transport restrictions impose, single phase ratings equal to one third of the three phase bank ratings may be specified.

Rating under ONAF condition although not guaranteed shall be about 80 per cent. Individual winding temperature rises shall be considered relative to that specified loading combination which is the most severe for the particular winding under consideration. The bushing shall be arranged in a line with mm spacing to allow mounting of phase to phase barriers.

Rated power frequency, short duration withstand voltage kV rms 28 38 50 - Specifications for kV Class Power Transformers 1. Notes : i Insulation of tertiary winding of auto-transformer should be adequate to withstand the transferred surge voltage appearing across them due to an impulse striking on HV or IV terminals. Therefore, 33 kV LV winding shall be designed for a minimum lightning impulse withstand voltage of kV peak and short duration power frequency withstand voltage of 95 kV rms.

The LV winding should be capable of withstanding the stresses as may be caused by frequent switching. One number of pump and one standby pump in each bank. Adequate number of fans and one standby fan in each 50 per cent bank. Two per cent coolers. It is required only in case specifically called fort. The clearances for HV and IV terminals shall be as tabulated below: Highest voltage for equipment kV rms 12 24 36 52 Two earthing terminals.

Magnetic type oil gauge with low oil level alarm contacts ratings: 0. Dial size mm. Copper tube interconnection between gas collection box and relay shall also be provided.

In transformers, for installation in areas subject to high seismic forces, i. Remote indication for each winding temperature shall be through a separate measuring system. Water flow indicator with alarm contacts ratings: 0.

Brass encased thermometer. Pressure gauges. Differential pressure gauge with alarm contacts, operating when difference between oil outlet pressure and water inlet pressure is less than 0. Note : The purchaser shall specify the type of cooling required before purchase. Oil filled condenser type bushings mounted on turrets, suitable for connections to bus bars in isolated phase bus ducts which shall have spacing of mm for each MVA single-phase unit of a MVA three-phase bank.

 

Cbip transformer manual free download -

 

This document was uploaded by user and they confirmed that they have the permission to share it. По этому сообщению you are author or own cbip transformer manual free download xbip of this book, please report to us by using this DMCA report form.

Report DMCA. Home cbip transformer manual free download Explore. Words:Pages: Mathur R. Chadha G. The transformre have taken utmost care to avoid errors in the publication.

However, the publishers are in no way responsible for the authenticity of data or information given by the contributors. Bhopal Members Downloac M. Goswami AGM Engg.

Power Grid Corp. Ballabhgarh, Haryana Shri K. Bhatia Addl. Vadodara Shri Hirdesh Downloae Dy. Malik Suptd. Majumdar Dy. Cbip transformer manual free download Addl. Katakwar Downloa Engineer Dist. Bhopal iii Shri S. Jhansi Cbipp C. Bhopal Shri R. Jhansi Shri B. Cblp Shri A. Agrawal Bharat Heavy Electricals Ltd. Bhopal Shri M. Mumbai Shri A. Ramchandran Asstt. Mahajan Consultant Voltamp Transformer Transformrr.

Mittal GM Retd. Kapur ED Retd. Since then we have made rapid progress and on date this figure stands at 1,23, MW. Matching with the generating capacity, transmission and distribution networks have also grown. Due to cbip transformer manual free download shortages, despite best cbip transformer manual free download the voltage and frequency in different grids sometimes varies beyond acceptable limits and lead to power cuts.

Transformer is a windows 10 home file sharing free link for taking power supply from generating station to consumer premises. Matching with Все pangu 10 for windows как growth in power sector, about 56, MVA power transformers and 26, MVA transformers for distribution network in the country are being manufactured annually.

In transmission and distribution sector, cost of the power transformer transfomrer the largest portion of the capital investment and financial consequences of failure of transformer lead to considerable loss of revenue besides break down of power supply. In early 70s, it was felt that industry should have detailed reference specifications for transformers.

This manual was subsequently revised in and in The transformer manual issued by CBIP is being widely used by power engineers as a reference book covering all aspects of transformers for almost all applications. Almost all transforker utilities in the country are referring the CBIP Manual on Transformers while formulating their own purchase specifications on the basis of technical information contained there in.

I am happy to transfomer that this manual has been revised and updated now with the help of Working Group experts from all eminent organizations, продолжить чтение contains the latest technological information including installation, testing, commissioning and repairs of transformers besides additional chapters on kV transformers, Condition Monitoring and Diagnostic Techniques and chapters on various components of the transformers of all sizes and voltages including dry type transformers.

I congratulate CBIP and all больше на странице of the Working Group for bringing out this manual covering latest state-of-art technology and I am sure that this document will be of great use cree engineering fraternity as a reference book.

In our country the transformers are subjected to severe stress condition due to wide variation in voltage and frequency in system due to нажмите чтобы перейти gap in demand and supply causing higher failure rate of transformers as compared to western countries. With the escalations in the cost of material and other inputs into its manufacture, the requirement of un-interrupted power and above all the steep rise in the cost of power has forced the manufacturers to compete in innovations and improvise designs as well as manufacturing practices to deliver a low-loss, competitive costing transformers with built-in monitoring features to считаю, opengl 4.3 for windows 10 хорошо its long troublefree service life.

On the other hand power utilities are also under immense pressure to maintain and upgrade their system cbip transformer manual free download meet the rising demand in power with no tolerance for any breakdown in supply. Moreover with the introduction of 'Availability Based Tariff, setting-up of the 'Electricity Regulatory Commissions' and the 'Consumer Grievance tranaformer Forums' all over the country, the essentiality of uninterrupted power now has a large commercial value.

In line with our cvip policy, to promote and coordinate professional excellence in water and power sector CBIP has prepared more than Manuals on all important subjects.

To disseminate the latest developments among the engineer's fraternity, CBIP has updated these manuals from time to time. First downloaf of the Transformer manual was published in and it was updated in and again in In this cbip transformer manual free download a chapter on 'Repair of transformer at site' has also been added. This trend of repair of transformer downlowd site is becoming popular since it saves in to and fro transportation time as well as HV test cost since some of the tests including HV Test are not to be repeated.

Cbip transformer manual free download thank all experts of the working group for their valuable contribution. I am sure that this Manual shall be of immense value and provide good reference document to the practising engineers especially those looking after planning, procurement, design, maintenance, testing and commissioning of power systems including transformers. All apparatus shall also be designed to ensure satisfactory operation under such sudden variations of load and voltage as may be met with transfrmer working conditions on the system, including those due to short circuits.

This clause is not downloaad to prohibit the use of suitable grades of cast iron for parts where service experience has shown it to be satisfactory, e. Manual on Transformers 2 1. Lock nuts shall be used on stud connections carrying current.

All leads from the winding to the terminal board and bushings shall be adequately supported to prevent injury from vibration including a systematical pull under short circuit conditions.

Guide pulls shall be used where practicable. The water extraction per tonne of insulation per hour may be limited to 50 grams maximum.

Alternatively dryness can be judged by dew point measurement. The zinc coating shall be smooth, clean and of uniform thickness and free from defects. The preparation cbip transformer manual free download galvanising and fransformer galvanising itself shall not adversely affect the mechanical properties of the coated material. The cbip transformer manual free download will be established by tests as downloqd IS: Alternative to mahual, zinc spraying or aluminising cbip transformer manual free download also be considered.

Transfomer preparation for galvanising itself shall not adversely affect the manusl properties of the wire. A matt or satin finish shall be provided to avoid dazzle from reflected light. Labels mounted on dark surfaces shall have white General 3 lettering on a black background. Danger notices shall have red lettering on a white background. After cleaning, these surfaces should be immediately covered with paint. The type and sownload of paint shall be chosen to suit pollution level at site.

Manual on Transformers 4 1. The total dry film thickness should preferably be between and microns. If heaters are not provided in the chamber, then the top coat should be of anti condensation cbip transformer manual free download. This is to be done by thoroughly cleaning the damaged area and applying the full number of coats as was applied originally.

Manufacturer should supply the necessary paint for this touch up painting at site. Supplier shall furnish necessary information on the make and grade of the top-coat paint. In general, it is possible to apply enamel paint over epoxy polyurethane coating and the vice versa is not recommended.

As hransformer as possible the make and grade of the recoat shall be same cbip transformer manual free download the original coat. The oil shall conform to IS : Alternatively, if the purchaser so desires, oil may be supplied in tankers directly from the refinery for transformers which are despatched from factory to site in gas filled condition.

Special measures, such as nitrogen sealing or the use of inhibited oil shall not be resorted to, unless otherwise specified by the purchaser. Normally oil immersed transformer shall be provided with conservator vessels. Where sealed transformers are specified, there shall be no conservator but adequate space shall be provided for expansion of oil without developing undue pressure.

The types of cooling shall be as stated in the relevant specifications. The forced cooling equipment shall come into operation by pre-set contacts in WTI and the transformer will operate as источник forced cooled unit.

In case bi-directional flow of power is required, that shall be specifically stated by the purchaser. If nothing has been stated by the purchaser, the test shall be carried out at the tapping with the manuual load losses. Note : Operation of a transformer at rated kVA at reduced voltage may ddownload rise to excessive losses and temperature rise 2.

General 2. Two leads from one yransformer corner of the delta connection shall be cbip transformer manual free download out to separate bushings. Links shall be provided for joining together the two terminals so as to complete the delta connection and earthing it ftee to the tank. Any transformer may be directly connected to an underground or overhead transmission line and switched into and out ссылка на страницу service together with its associated transmission line.

However, the purchaser will install the over fluxing protection device in case of generator step-up transformers. Note : All inter-connected tra nsformers of 50MVA and above shall also be provided with over fluxing protection device by the purchaser. Manual on Transformers 8 2. The tolerance on the losses of each manuao shall be in accordance with IS : Any specific requirement may be vree at the time of enquiry as a prequalification instead of at the time of order.