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A problem arises in 3-phase systems when the loads draw harmonic currents.

This can happen with a load like a TV set which contains rectifiers to produce a dc supply for its electronic circuits. The load current waveform is not a perfect sine wave and it can be analysed in the frequency domain as the sum of a fundamental current at 50 Hz (in Europe) and harmonics at 100, 150, 200, 250 Hz etc. This is done by Fourier analysis.

The triplen harmonics are the odd-multiples of 3, in other words the 3rd, 9th, 15th etc. and cause problems in 3-phase systems. In a balanced 3-phase 4-wire system there is zero current in the neutral wire, but when there are triplen harmonics in the load current, there is current in the neutral even when the currents are balanced (i.e. equal in all three phases), because the triplen currents add while the fundamental-frequency currents cancel out in the neutral.

Unnecessary currents cause additional losses in the power transmission network and therefore transmission engineers try to minimise them.

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Q: What is the term harmonic when refering to a three phase transformer?
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What is the current of 1MVA transformer?

This depends on the voltage, and whether it is a three phase or single phase transformer.


What is this system called with three single phase transformer?

Your question is rather vague. If you are asking what do you call a group of single-phase transformers, connected to supply three phase, then the answer is a 'three-phase transformer bank'.


Would you install three-phase transformer or bank of three single phase transformer in a large power station and justify by comparing the two schemes?

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Is there a basic difference between a three phase power transformer and a three phase distribution transformer?

The basic difference is the secondary voltages. On a distribution transformer the secondary voltage is very high. This is to overcome line loss for transmission of electricity over long distances. A three phase power transformer is used at the consumers three phase services end to manipulate voltages that consumers need to operate their equipment. The transformer that feeds your house is considered to be a single phase power transformer.


Is there a neutral on a three phase transformer?

It depends on whether you are wye or delta connected. A transformer is a transformer, and a three phase transformer is simply three transformers. The key is in how you hook them up.AnswerIt depends on how the transformer is connected. If one set of windings is connected in star (or wye), then the star point is/canbe earthed and becomes the neutral for that particular connection; this is the standard connection for the secondary (low-voltage) of European distribution transformers. In North American three-phase distribution transformers, the secondary windings are connected in delta, and one phase is centre tapped, earthed, and that becomes the neutral point for a 240/120-V split-phase supply to a residence.This answer applies to both three-phase transformers, and to single-phase transformers which have been connected to form a three-phase transformer bank. (It is incorrect to say that a three-phase transformer is simply three single-phase transformers!)


Can 3 single phase transformers can replace 1 three phase transformer?

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What will happen if apply two phase supply to a three phase transformer?

A three phase transformer is simply three transformers so, supplying one phase to a set of three transformers will result in only one phase output. Any loads connected to that transformer that are expecting three phase power will malfunction, and could fail.AnswerA three-phase transformer is NOT 'three separate single-phase transformers', as suggested in the original answer. It is a single transformer with three primary and secondary phase-windings wound around a common three-limb ('core') or five-limb ('shell') core. If a single-phase supply was applied to one of the three primary windings, then single phase voltages would appear across each of the three secondary windings and the remaining two primary windings. These voltages would not be out of phase with each other.


Where are three phase transformer systems used?

Any where that a three phase supply distribution is needed to operate three phase equipment.


Why would you use a three phase transformer in place of a single phase transformer?

the necesscity of two three phase transformers operating in parallel are as follows...if the one transformer fails to give supply,then another transformer can be used in parallel and hance,continuity of supply can be maintained.one transformer can be easily take out from the supply for repair & maintanance.if the load on the substation increases beyond the rated values of transformer, then another transformer can be used to share rhe load of the substation.


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Why vector group is required?

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