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

Your Answer

In order to provide an answer to this question, you must Login

I am flagging this question because...

10 inform moderator flags remaining

I am deleting this question because...

I am flagging this answer because...

10 inform moderator flags remaining

Flagging a Post

You have already flagged this post. Clicking "Remove Flag" below will remove your flag, thus reducing the count by one as well.

I am deleting this answer because...

What is a rectifier transformer?

I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here. A rectifier transformer is a transformer...

Cable Sheath and Armour Loss

When sizing cables, the heat generated  by losses within any sheath or armour need to be evaluated. When significant, it becomes a factor to be considered...

Lithium Ion Battery

Over recent years the Lithium Ion battery has become popular in applications requiring high power densities with small weight and footprint.  Today Lithium...

Frame Leakage Protection

While not as popular as it once was, frame leakage protection does still have some use in some circumstances.  In essence frame leakage is an earth fault...

Capacitor Theory

Capacitors are widely used in electrical engineering for functions such as energy storage, power factor correction, voltage compensation and many others...

Three Phase Power Simplified

A single phase system is perhaps the most common type of system most people are familiar with. This is what people have in their homes and what appliances...

Arc Flash Calculations

Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash...

UPS Battery Sizing

Various techniques exist to enable the correct selection of batteries for UPS applications.  The procedure described below is one of the more common. ...

EU Code of Conduct on Data Centres - Best Practices

The European Union is implementing a voluntary code of practice for participants with the aim of improving the overall efficiency of data centres. As part...

ANSI (IEEE) Protective Device Numbering

The widely used United Sates standard ANSI/IEEE C37.2 'Electrical Power System Device Function Numbers, Acronyms, and Contact Designations' deals with...

Our website uses cookies so that we can provide a better experience.
To learn more about what cookies are and how to manage them visit AboutCookies.org