Transformer Efficiency - IRD India

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International Journal of Electrical, Electronics and Computer Systems (IJEECS)

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ISSN (Online): 2347-2820, Volume -5, Issue-3_4, 2017 1

Transformer Efficiency: A review

Mahantesh S Patil

Dept of Electrical and Electronics, University Visveswaraya College Of Engineering Abstract— The registered applications of transformers

using machine learning which of these transformers ultimately connected to each others in domestic applications by the concept of data mining and accordingly to data analysis ,the calculation of voltage and current which should be known or the capacity of current and voltage which a transformer can resist ,without blowing up or bursting by pre-defined characteristics such as, losses and the core flux in the transformers can resist ,which profoundly explain about how that can be programmed without exactly programming and about controlling the properties like density ,iron losses ,copper losses, hysteresis loss ,open circuits tests. The efficiency of transformer at a particular load is and power factor which can be measured in watts. It also depends on the type of materials used and ratings in KVA.

Keywords— Transformer, Effency, load power.

I. INTRODUCTION

Transformers are re-connected in arrays or connected in a sequence of series to networks. That itself can be linked with data mining with registered applications with machine learning as it uses custom data analysis which can be used in pre calculation of current and voltage reduction with retained analysis of big data ,that is the whole analysis of working of transformer. As using the applications of data mining with introduced data modeling concepts , transformers can be reformed together and can ultimately control the voltages of consecutive arrays or sequence of transformers with this concept these connected transformers can be controlled in a whole lot of one system that will be in hold with other consecutive transformers ,by this technique if we use this concept then there will be no busting or blowing up of transformers with increased capacity of voltage which can be controlled using machine learning concept. This will also help in the installation of some particular customized transformers.

Figure 1: Real view of transformer.

II. LOSSSES IN TRANSFORMERS

As,in transformer there is no friction or windage losses .so the only losses could be occurring are:1.iron loss.- the iron losses of a transformer depends upon the frequency and the maximum flux density when the volume and the thickness of the core laminations are given. These losses occur when on no-load as input of transformer measures .it includes eddy current losses and hysteresis losses, the core flux in the transformer remains constant for all loads .as it will be varying from no-load to full-load.the iron losses are practically same at all loads. This type of losses are found in open circuit tests, these losses are minimized by using steel of high silicon content for the core and by using thin laminations.

III. TOTAL IRON LOSSES

copper loss.-this loss comes into act because of ohm resistance of transformer winding .it is clear that copper lose is proportional to square of current .in other words ,cu loss at half the full-load is one-forth of that at full load. this value of copper loss is found through the short-circuit test of transformer .

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1

1 1

2 1

1

2 2

( sin ) (1)

cos (2)

sin( ) (3)

2

4.44 (4)

2 (5)

m

E N d wt

dt

E N w wt

E fN



 



 

 



Wi = wh +we . (6)

As ,seen in the copper losses of a transformer depends on current and iron loss on voltage .hence,total transformer loss depends on volt-amper (VA) and not on phase angle between voltage and current ,i.e it is independent of load power factor .this is why rating of transformer is in KVA and not in KW.

IV. EFFICIENCY OF TRANSFORMER

The efficiency of a transformer at a particular load is and power factor is defined as the output divided by the input –the two being measured in watts or k watts.

Efficiency =output/input.

Efficiency=output/output + losses.

Efficiency=input - losses/input.

2 2

1 2 2 2

2 2 2

2

1 2 2 2

2

cos (7)

cos

(8) (9) (10) (11)

P P

P

P P P

P

VI

VI losses I V

Z

Z R X

w R

R R

R w L w n wL X wL

R w L

 





 



 



 



Efficiency can be computed by determining core losses or open circuit test and cu loss from the short circuit test.

When core losses and iron losses become equal the effect will be maximum efficient ,at that time. All day efficiency is the efficiency of transformer where it is prolonged with load with 24 hour ,that is a day. these transformers are used in general electric networks and to supply electricity all round domestically .thus the supply and all day distribution with the usage is all day efficiency of transformer. This is also the efficiency of

the transformer, where based on the performance of transformer as per the load and how long the transformer can be loaded during 24 hours. The performance of such is based on the basis of energy consumed during certain time period, usually a day of 24 hours. We can know the all day efficiency by knowing the load factor.

Efficiency all –day =output in Kwh/input in Kwh (for 24hours).

V

o

in volts

I

_f in amperes

42 0.16

50 0.19

60 0.24

70 0.28

80 0.33

90 0.4

100 0.43

110 0.53

120 0.65

Table 1: Efficiency of transformer.

Figure 2 :Graphical representation .

V. LOSSES IN TRANSFORMER

There are two types of transformers; namely core or iron losses and copper losses. core loss or iron loss: it includes both hysteresis and eddy current losses. because the core flux in transformer remains constant for all loads. The core loss is practically same at all loads. The reason we excite standard (asynchronous) ac generators with DC excitation .the DC excitation provides a steady magnetic field in the rotor .As the rotor spins ,the steady field becomes a rotating output. steady rotor electromagnetic field becomes rotating output (ac)voltage.

Frequency (hz)

V in volts

I in amps

W in watts

W/f

55 440 0.24 7 0.5

50 400 0.26 6 0.4

45 360 0.36 4 0.35

Table 2: Losses in transformers.

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Attempts will be made in the design of switchable transformer by rearranging the primary and secondary windings to increase the efficiency throughout the interval of any variation in the load. Instead of having one particular value of maximum efficiency with one fixed winding arrangement, two arrangements of windings on both primary and secondary will be utilized. These two arrangements of windings are made to have two values of maximum efficiency in two different points of the load. The graph is explanation of efficiency of transformer by open circuit and short circuit tests, which is computed together and supply and all day efficiency and energy transformation taken throughout the running of transformer. The maximum value of the field circuit resistance for which the machine just excites and beyond which fails to excite and generate EMF . It is the value of field circuit resistance below which machine can build up voltage but beyond which it cannot generate emf. It is given by the slope in the graph drawn tangentially from origin .

VI. EXPERIMENTAL EXPLANATION

As the graph which is v/s voltage and current, so as current and voltages increases the critical field resistance’s beyond which cannot generate voltage which effect efficiency. This graph is drawn to know the losses in transformers that is the eddy current loss and hysteresis losses of transformers .here the core loss that is experimented values of watt meters at the particular frequencies are counted so those values are tabulated in the table. As the measurement of frequency is externally done .and by this the voltage and current losses are calculated . Savings of energy are made possible using the hybrid transformer with its series and parallel winding configuration features. This transformer enhances efficiency of conventional transformer by reducing the core loss at low loads and the copper loss at high loads. During the operation of the hybrid transformer, the series configuration is applied to low loads to reduce the flux density while the parallel configuration is applied to high loads to reduce the winding resistances. More visible savings of energy can be expected from hybrid transformers having higher power ratings compared with a conventional transformer having the same power rating. Thus, the strategy of implementing the hybrid transformer may provide a major advantage in the contribution of either short-term or long-term energy saving programs

2 1

1 2

Z (12) I  Z Z



,

I

₁

is load current of trans former

and

1 2

are the impedances of transfor

Z and Z mers

1 2

Z (13) I  Z Z



,

I

₂

is the load current of transformer 2

.

VII. CONCLUSIONS

In these articles, essential of transformer depends on the efficiency and power supply. There are two data sets with real value demonstrate in this paper. The measurement of frequency is externally done using voltage and current losses. For calculation of energy are made possible using the hybrid transformer with its series and parallel winding configuration features.

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