Answer / raghavendran

I am not sure but,this could be the reason, the Electrical
field intensity producing corona on contaminated areas,
water droplets, icicles, corona rings, ... This corona
activity then contributes nitric acid to form a chemical
soup to change the bonding cements and to create carbon
tracks, along with ozone and ultraviolet light to change the
properties of NCI insulator coverings. Other detrimental
effects include water on the surface or sub-surface freezing
and expanding when thawing, as a liquid penetrating into a
material and then a sudden temperature change causes change
of state to a gas and rapid expansion causing fracture or
rupture of the material.

Answer / aboli

I think impure water or ice being good conductor of
electricity,due to ice coating the insulator may get
directly short ckted.this could be called as puncturing of
insulator by ice coating.

what is the meaning of Ring Mean Unit in a substation or trasformer also tell me its oerpuse?

4 Answers   NPTC, NTPC,

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-What should be minimum value of insulation resistance and maximum value of earth resistance at any electrical instillation and what is method of testing the same.

0 Answers  

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why we use to transmit the power in three phases intead of single phase ?

4 Answers  

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What do you mean by a current transformer?

0 Answers  

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How would you supply power to a village which is very far from a sub-station and has only a 11k?

4 Answers   Power Grid,

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Shall we get electrical shock if we touch the positive terminal of a 230 volt dc supply?

22 Answers   Essar,

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at what condition restricted earth fault relay will act?

1 Answers   Equate,

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How much resistance between neutral earthing and body earthing of Power transformer?

1 Answers  

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in dc series motor if field wdg is shorted then

0 Answers  

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For Bus duct hi pot test, where we want to connect the return and ground leads?

2 Answers  

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What is an Isolation Xformer? What is the use of it?

2 Answers  

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can anyone pls expain me about how can we design a cable tray??suppose if have to draw a 3 nos of 50 sqmm AYFY and 2 nos of 35 SQmm of AYFY cable through the tray..how can we design the tray size?? regards...

3 Answers  

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