Answer / sunil ulange

There are 2 types of CT's
1. Measuring purpose CT - Class 0.2, 0.1
2. protection Purpose CT- class PS, 5p10, 5P20

Class 0.2 - 0.2 Accurcy for meters.
Class PS- means Protection Purpose relays, breakers etc.
Class 5P10 - means 5% accuracy, P -protection, carry 10
times normal current

any Substation related questions ask me @ sunil_031@yahoo.com
Sunil Ulange
Project Engineer
Greenesol power Systems bangalore

Answer / ahamar

5P is a protection class of current transformer.CT,s are of
three types,for current measuring,for protection and
special protectin class.

Answer / amin

Explain the Term in CT Name Plate – Class: 0.2fs5
FS ?

how to calculate the cable size for 500 kva transformer?

3 Answers  

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How to find Cable size? Caterpillar generator produce (Two generators) 127*2=254 amp at 11 kv . What would be the cable size (XLPE) to supply 256 amp at 11 kv? Air or surrounding Temperature is 32 degree C. Cable will go under ground at 2.5 feet depth. Group Rating Factors is 3 cables. Clearance between cables is 7 cm. Soil Temperature (Ambient) 28o C Soil Thermal Resistivity is 1.2 K.m/W I would like to use 3 separate single core instead of using 3 core cable. Some says I should use three separate single core 120RM cables. Some says 70RM .some says 95. I m totally confused. Is there ant specific rule to determine cable size? What would be the LT cable size to flow 500 Amp current? Ifte My e mail address is ifte13@yahoo.com Anyone please send me the answer to my e mail address, i will be very glad.

1 Answers  

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If single phase supply is 220v. then why three phase supply is 660?

2 Answers  

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which motor is used in our Indian Ceiling fan -Capacitor start and run or Capacitor start? (during repair i saw only one capacitor so it should be start only)

5 Answers   ABB, Bajaj Electricals, Power Grid, Ruchi Soya, Suzuki,

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We have 11kV/110V three phase indoor potential transformer in 66/11kV Sub-station, where the failure of PT is frequently happening and the rating of the PT is 0.2 class accuracy, with primary star and seconday (two cores) star connected. Some experts has suggested to not to connect the PT Primary neutral to the ground because when transformer neutal NCT connection is loose; the faulty current will flow through the PT primary neutral, resulting into failure of PT. My question is: Is it necessary to remove the primary neutral connection of the PT from ground? if not, what would be the reason for failure of PT. Please guide me.

2 Answers   KPTCL,

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what perpose of use CT ratio in gt,st,uat

1 Answers  

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extremely urgent please, why a fuse is used before voltmeter but not with a ammeter connected to a CT(current transformer),thanks in anticipation.

4 Answers   NPCIL,

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what is servo motor principle? difference between induction motor & servo motor?

1 Answers  

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why voltage coil in wattmeter called as pressure coil why the pressure term is used in wattmeter?

1 Answers   NPCIL,

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What is mean by STUB protection?

0 Answers  

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how can i get the formula to find out the cable size if i know the load of main fuse protection.

0 Answers  

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Can any one provide the inspection procedure of MIMIC for VFD panel? Details: If someone wants to have a mimic in the VFD panel what are inputs considered for the mimic(like on,off,trip) whether we are able to add speed variation in the mimic(if so how can we get) and what are the parameters to be checked in the MIMIC during inspection?

0 Answers  

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