Wednesday, 21 March 2018

What Is The Tap Changing In The Electrical Transformers ?

What Is The Tap Changing In The Electrical Transformers ? 



What Is The Use Of Tap Changing In Transformer And How Its A Useful For The Output Of The Transformation!! 




The Tap Changing may be done when the transformers are disconnected from the circuit or when Operating On Load.






Tap Changer is fitted with the transformer for adjusting the Secondary voltage.


The modern practice is to install the tap-changer with the Transformer Tank.

There are two types of Tap-changers:


  • (i) OFF-circuit Tap Changer
  • (ii) ON-load Tap Changer (OLTC)




OFF-Circuit Tap Changer 

(A) 

Abov Figer(A) show the arrangement of off-load Tap Changers.

Normally (+)or(-)2.5  and (+)or(-)5% tappinge are provided on The Transformer Winding for regulating the voltage.

Occasional Adjustments in second voltage can be made by off circuit Tap changer .

The tap can be changed only after opening the circuit breaker on supply aide i e. The transformer is disconnected from the circuit.



ON-load Tap changer (OLTC)

The daily or Short Time Voltage Adjustments is made by ON- load tap changer (OLTC).

The tappings of ON-load tap changer can be changed without interruption of load current or Power Supply.

Figer(B) shows in below the Basic Diagram of ON-load tap changer(OLTC).

(B) 

The Tap Changer is operated by motor drive unit by local or remote control and a handle also fitted for manual operation in case of an emergency.

The pair of resistors are provided to limit the short cireuit current-during the operation of Tap Changer

The Tapping are provided on the high voltage(h. v.) winding as shown in Figer (C) because of the following reasons:

(C) 


  • (i) The number of turns in High Voltage winding (h.v.) is large and therefore a fine voltage regulation can be obtained.
  • (ii) The Current on the h.v. side is small.
  • (iii) The Lv. winding is placed on the inside nearer to the core while hv winding is placed on the outside.


Therefore, from Practical Considerations it is proferred to provide on hv winding.





Question part Of This Article Which helps You For Better Understanding :

(1)when we can done tap changing in transformer???
Ans:The tap-changing may be done when the transformers are disconnected from the circuit or when operating on load.


(2)how manny type will be there for tap changing in transformer???
Ans:There are two types of Tap-changers:
 (i) OFF-circuit Tap Changer
(ii) ON-load Tap Changer (OLTC)


(3)which type of tap changing is made by ON- load tap changer (OLTC). ??
Ans:The daily or short time voltage adjustments .


(4)give the reason The tapping are provided on the high voltage(h. v.) winding?????
Ans:reason is give as below:
(i) The number of turns in High Voltage winding (h.v.) is large and therefore a fine voltage regulation can be obtained.
(ii) The current on the h.v. side is small.
(iii) The Lv. winding is placed on the inside nearer to the core while hv winding is placed on the outside.


(5)practical considerations tap changer is proferred to provide on which winding.??

Ans: high voltage



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1 comment:

  1. Very useful for engineering students keep up to date

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