What is a current tranformer class?

asked 4/17/2012

4 Answers

A current transformer's class, accuracy class, to be more precise, signifies the error of the CT.

For metering CTs, the designated accuracy classes are 0.1, 0.2, 0.5, 1.0, 3.0 & 5.0;

For tariff metering, the classes are 0.2S & 0.5S

For general protection, the classes are 5P, 10P & 15P with ALF (Accuracy Limiting Factor) of 5, 10, 15, 20 & 30.

For Unit Protection Schemes, the classe is Class PS.
answered 4/10/2013 EE65 19

Metering: 0.2S for Revenue Metering, 0.2 in  Measuring in Power  Plants & industries for internal Purpose, 1 for Domestic Reading

Differential & REF Protection: PS

Protection: Like over current, earth fault, Reverse Power, under Power etc., 3P5, 3P10, 5P5, 5P10, 5P20.

The above classes are used practically.

answered 9/8/2012 JANAKI RAM 3
CL :0.2,0.5,1.0,1.5,5P10,5P15,5P20,PS.
answered 4/28/2012 trex 1
The transformer class relates to it's accuracy. There are two different ways to represent this, depending if the current transformer is to be use for protection or metering.

Previously I have put a few posts in the site, going into more detail on current transformer classes. If you type 'current transformer' in the site search (top right of the page), you'll find these.
answered 4/20/2012 Steven McFadyen 246
Steven McFadyen

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