Explain working of three-phase transformers, Electrical Engineering

Assignment Help:

Q. Explain working of three-phase transformers?

Transformation in three-phase systems can be accomplished in either of two ways: (1) connecting three identical single-phase transformers to form a three-phase bank (each one will carry one-third of the total three-phase load under balanced conditions); or (2) a three-phase transformer manufactured for a given rating. A three-phase transformer, compared to a bank of three single-phase transformers, for a given rating will weigh less, cost less, require less floor space, and have somewhat higher efficiency.

The windings of either core-type or shell-type three-phase transformers may be connected in either wye or delta. Four possible combinations of connections for the three-phase, two- winding transformers are Y- Δ, Δ -Y, Δ -Δ , and Y-Y. These are shown in Figure with the transformers assumed to be ideal. The windings on the left are the primaries, those on the right are the secondaries, and a primary winding of the transformer is linked magnetically with the secondary winding drawn parallel to it. With the per-phase primary-to-secondary turns ratio (N1/N2 = a), the resultant voltages and currents for balanced applied line-to-line voltages V and line currents I are marked in the figure.

2459_Explain working of three-phase transformers.png

As in the case of three-phase circuits under balanced conditions, only one phase needs to be considered for circuit computations, because the conditions in the other two phases are the same except for the phase displacements associated with a three-phase system. It is usually convenient to carry out the analysis on a per-phase-of-Y (i.e., line-to-neutral) basis, and in such a case the transformer series impedance can then be added in series with the transmission-line series impedance. In dealing with Y- Δ and Δ -Y connections, all quantities can be referred to the Y-connected side. For Δ- Δ connections, it is convenient to replace the -connected series impedances of the transformers with equivalent Y-connected impedances by using the relation.

2044_Explain working of three-phase transformers1.png

It can be shown that to transfer the ohmic value of impedance from the voltage level on one side of a three-phase transformer to the voltage level on the other side, the multiplying factor is the square of the ratio of line-to-line voltages, regardless of whether the transformer connection is Y-Y, Δ -Y, or Δ -Δ . In some cases, where Y-Y transformation is utilized in particular, it is quite common to incorporate a third winding, known as tertiary winding, connected in delta. Such multiwinding transformers with three or more windings are not considered in this text.


Related Discussions:- Explain working of three-phase transformers

Briefly explain about wheatstone bridge, Q. Briefly explain about Wheatston...

Q. Briefly explain about Wheatstone Bridge? Null measurements are made with bridge circuits and related configurations. They differ from direct measurements in that the quantit

Blanking circuit, Blanking circuit: The saw tooth sweep voltage applied to...

Blanking circuit: The saw tooth sweep voltage applied to the X places moves beam across the CRT tube in a straight horizontal line from left to right during the sweep or trace tim

Cro, Diagram and explanation of cro

Diagram and explanation of cro

C R O DELAY LINE, WHAT IS THE FUNCTION OF DELAY LINE IN CRO

WHAT IS THE FUNCTION OF DELAY LINE IN CRO

Produce a storage scope using peripheral interface control, First section ...

First section Aim: the aim of this project is to produce a storage scope using a PIC. In this project, several samples were taken from an analog signal and stored in the memo

Explain properties and application of copper, Explain properties and applic...

Explain properties and application of Copper. Properties 1) Cooper is reddish brown in color. 2) Cooper is malleable and ductile and can be forged, cast, rolled, mach

Determine the voltage across the capacitor, (a) Let a unit impulse of curre...

(a) Let a unit impulse of current i(t) = δ(t) be applied to a parallel combination of R = 3 and C = 1/2 F. Determine the voltage vC(t) across the capacitor. (b) Repeat (a) for

Sui subtract immediate i instructions , SUI  Subtract Immediate I Instruct...

SUI  Subtract Immediate I Instructions The 8 bit  data  specified  in the  instruction  is directly  subtracted  from the  contents of  accumulator  and results  of operation

Gis applications in management of power distribution systems, GIS Applicati...

GIS Applications in Management of Power Distribution Systems: a.)        Inventory of existing network. b.)        Easy access to network details. c.)        Easy access

Motor, delta connectino purpose

delta connectino purpose

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd