Efficiency Improvement Of An Electrical Transformer By Design
Development Of FINS
1Mutyala Anil Kumar 2A.V.Sridhar 3V.V Ramakrishna 4Y.Dhana Sekhar 1M. Tech. Student, 2Associate.Professor,3Assistant.Professor
Dept Of ME, KITS , DIVILI
4Reserch Scholar
ABSTRACT:
A transformer is an electrical gadget that exchanges electrical energy between two or more circuits through electromagnetic affectation. Normally, transformers are utilized to increment or diminish the voltages of exchanging current in electric force applications; a differing current in the transformer's essential winding makes a changing attractive flux in the transformer center and a shifting attractive field impinging on the transformer's auxiliary winding. This fluctuating attractive field at the auxiliary winding affects a shifting electromotive power (EMF) or voltage in the optional winding. Making utilization of Faraday's Law in conjunction with high attractive porousness center properties, transformers can along these lines be intended to proficiently change AC voltages starting with one voltage level then onto another within power networks.
Copper losses are resistive and proportional to load current and aresometimes called “load losses”, as the
transformer is loaded; heat is produced in the primary and secondary windings and connections due to losses. At low loads, the quantity of heat produced will be small but as load increases, the amount of heat produced becomes significant at full load, the windings will be operating at or near their design temperature, Figure shows the relationship between load-current and the heat produced in transformer windings and connections.
If the ambient temperature is too high then the transformer will automatically fail to work , even though some coolants are employed in the transformers to carry away the heat, they are not enough during summer seasons so there is a need to develop better cooling systems
In this project we develop better cooling system for a transformer using 3D modelling and Finite Element Methods so that the transformers will work without fail. For 3D modelling we use Catia V5 R20 and for finite element analysis we use Ansys 15.0
1.INTRODUCTION
Electromagnetic induction produces an electromotive force across a conductor which is exposed to time varying magnetic fields. Commonly, transformers are used to increase or decrease the voltages of alternating current in electric power applications.
A varying current in the transformer's primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the transformer's secondary winding. This varying magnetic field at the secondary winding induces a varying electromotive force (EMF) or voltage in the secondary winding due to electromagnetic induction. Making use of Faraday's Law (discovered in 1831) in conjunction with high magnetic permeability core properties, transformers can thus be designed to efficiently change AC voltages from one voltage level to another within power networks.
Since the invention of the first constant potential transformer in 1885, transformers have
become essential for the transmission, distribution, and utilization of alternating current electrical energy. A wide range of transformer designs are encountered in electronic and electric power applications. Transformers range in size from RF transformers less than a cubic centimeter in volume to units interconnecting the power weighing hundreds of tons.
2. Temperature Rise in a Transformer
structures of the transformer. When all is said in done, more proficient transformers have a tendency to have lower temperature rise, while less effective units have a tendency to have higher temperature rise.
Transformer temperature rise is characterized as the normal temperature ascent of the windings over the (encompassing) temperature, when the transformer is stacked at its nameplate rating.
Fig1. The relationship between burden current andthe heat created in transformer windings and associations.
2.1 Standard Ratings and Overload Capacity
Dry-sort transformers are accessible in three standard temperature rises: 80C, 115C, or 150C. Fluid filled transformers come in standard ascents of 55C and 65C. These qualities depend on a most extreme encompassing temperature of 40C. That implies, for instance, that a 80C ascent dry transformer will work at a normal twisting temperature of 120C when at full-evaluated load, in a 40C encompassing environment. (Alleged problem areas inside of the transformer might be at a higher temperature than normal.) Since most dry transformers utilize the same protection on their windings (commonly evaluated at 220C), regardless of the outline temperature rise, the 80C ascent unit has more space for an intermittent over-burden than a 150C ascent unit, without harming the protection or influencing transformer life.
3. ANALYSIS
IMPORT MODEL 1
IMPORT MODEL 2
IMPORT MODEL 3
IMPORT MODEL 4
MESHING ON MODEL 2 WITH COPPER
MESHING ON MODEL 3 WITH AL7075
MESHING ON MODEL 4 WITH COPPER
TEMPERATURE
CONVECTION
IMPORTED MODEL 2 WITH COPPER
RADITATION
IMPORTED MODEL 3 WITH Al 7075
TOTAL HEAT FLUX
DIRECTIONAL FLUX
IMPORTED MODEL 4 WITH COPPER
TOTAL HEAT FLUX
DIRECTIONAL FLUX
RESULTS AND GRAPHS
TEMPERA
TURE HEAT FLUX
DIRECTIONA L HEAT
FLUX
MIN MA
X MIN MAX MIN MAX
MOD EL 1
AL70
75 52.4 150
0.001 4 1183 9 -7285.3 8267 COPE
R 61.5 150
0.001 2 2527 1 -6336.3 8066. 5 MOD EL 2 AL70 75 47.73 150. 1 2.83 4093 7 -5861.8 4082 6 COPE R 51.49 150. 1 3.06 6512 4 -15603 6407 7 MOD EL 3 AL70 75 46.26 150. 8 3.45 5601 5 -11378 4005 2 COPE R 48.17 150. 7 6.284 2 6927 6 -29039 6025 8 MOD AL70
75 82.39 150
TEMPERATURE GRAPHS FOR AL7075
Graph1: Graph showing the Min Temperature report for Al 7075
Graph2: Graph showing the Max Temperature report for Al 7075
TEMPERATURE GRAPHS FOR COPPER
Graph3: Graph showing the Min Temperature report for Copper
Graph4: Graph showing the Max Temperature report for Copper
HEAT FLUX GRAPHS FOR AL 7075
Graph5: Graph showing the Min Heat Flux report for Al 7075
0 20000 40000 60000 80000 100000
MODEL
1 MODEL2 MODEL3 MODEL4
MINIMUM
149.4 149.6 149.8150 150.2 150.4 150.6 150.8151
MODEL
1 MODEL2 MODEL3 MODEL4
MAXIMUM
0 20 40 60 80 100 120 140
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MINIMUM
149.5 150 150.5 151
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MAXIMUM
0 1 2 3 4
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MINIMUM
0 10000 20000 30000 40000 50000 60000
MODEL 1 MODEL 2 MODEL 3 MODEL 4
Graph6: Graph showing the Max Heat Flux report for Al 7075
HEAT FLUX GRAPHS FOR COPPER
Graph7: Graph showing the Min Heat Flux report for Copper
Graph8: Graph showing the Max Heat Flux report for Copper
DIRECTIONAL HEAT FLUX GRAPHS FOR AL7075
Graph9: Graph showing the Min Directional Heat Flux report for Al 7075
Graph10: Graph showing the Max Directional Heat Flux report for Al 7075
DIRECTIONAL HEAT FLUX GRAPHS FOR COPPER
Graph11: Graph showing the Min Directional Heat Flux report for Copper
0 1 2 3 4 5 6 7
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MINIMUM
0 10000 20000 30000 40000 50000 60000 70000 80000
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MAXIMUM
-20000
-15000
-10000
-5000
0
MODEL 1 MODEL 2MODEL 3 MODEL 4
MINIMUM
0 10000 20000 30000 40000 50000
MODEL 1 MODEL 2 MODEL 3 MODEL 4
MAXIMUM
-40000
-30000
-20000
-10000
0
MODEL 1 MODEL 2MODEL 3 MODEL 4
Graph12: Graph showing the Max Directional Heat Flux report for Copper
CONCLUSION
In this project we develop better cooling system for a transformer using 3D modelling and Finite Element Methods so that the transformers will work without fail. As we observe in this project we have designed 4 types of fin models for the transformer, and three different existing transformer fins and one new model. As per the results obtained from the thermal analysis, we have done analysis with 2 materials that is copper and Al 7075 alloy, as if we compare in model 1 flux is high for the copper material. But least temperature is recorded in model 1 made of aluminium. Similarly in model 2, 3 and 4 fluxes are high in copper model but lowest temperature is recorded in aluminium models. When we compare all the model, the lowest temperature is recorded in model 3 made with aluminium and highest fluxes are in model 4 made with copper. Finally from this we conclude that model 3 made up copper or aluminium will help to reduce the oil coolant to ambient temperature, so we suggest to replace steel (present material) with aluminium 7075 as if we replace present material with copper insulation will become a problem.
REFERENCE
[1] Transformers & Induction Machines, M.V.BakshiU.A.Bakshi, Technical Publications,
[2] Electrical Transformers and Power Equipment, Anthony J. Pansini, The Fairmont Press, Inc., 1999
[3] Handbook of transformer design and applications, William M. Flanagan, McGraw-Hill, 1993
[4] Electric Power Transformer Engineering, Third Edition, Volume 2, James H. Harlow, CRC Press, 2012
[5] Electric Power Transformer Engineering, Second Edition, James H. Harlow, CRC Press, 2007
0 10000 20000 30000 40000 50000 60000 70000
MODEL 1 MODEL 2 MODEL 3 MODEL 4
