Understanding CTs and PTs in SLD

Wrong, the range of ratios is different, as is the range of burdens, the only thing identical about them is their accuracy class. Why do you think they have a different number of cores, what are your doubts, was this an interview question?

thanks, no its not interview question , its just for understanding SLD,

i think that they have different number of cores because ,

one has written , 0.2FS5/5P20/5P20/5P20 (1 metering core, 3 protection cores)

and second is only 0.2FS5 cores, written in SLD, ?

second what is wrong in Ratio and Range of burdens,

please reply ,

Hi there,

As RAMConsult said, it´s wrong. Not the Current Transformers, not the data, just the thinking.

The CTs do not have different number of cores because of what is written on them but because who needed them just wanted them in this way.

Next, there is nothing wrong with the ratio and burden values. There are just suited for different contexts.

nikolay

why 5P20 written 03 times and 0.2FS5 written 01 times . are they 03 and 01 cores ?

OK, let's get specific with the language.

First idea, the core is called secondary winding. Usually and technically each winding has its own steel core. In general just by looking directly at a transformer one can not see the actual number of cores but can see the number of winding terminations. For this reason is appropriate to account for number of secondary windings.

Second idea, some CTs have one secondary winding, others have more of them. Depends all on the purpose of the CT.

Your first CT on the list has 4 secondary windings (0.2FS5 for metering and the rest 5P20 for protection) and the second CT on your list has only one metering winding, 0.2FS5.

Warning: If planning to use of work with CTs, be sure to short the unused secondaries. Always de-energize the equipment before working on it.

Get qualified personnel to work on it. Make sure you don't get killed or endanger anyone else.

thank you very mush nikolay

Don't you know How to Search the Internet: 9 Steps (with Pictures) ?

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Then a simple telephone call to the equipment supplier would be a far quicker way towards achieving understanding than waiting for the right answer to appear on CR4, among all the duff answers. CR4 does not offer training in the use of the telephone.

Both CTs are of multi ratios,.. and the difference lies here: you can use the first one for protection purposes, as well as you can take advantage of the turn "400/1" for metering purposes... With regards to the second CT, it's used for metering purposes only!!

I hope this helps!!

thansk ali,

what is 04 or 05 cores CT, ? most commonly use is single core or multi cores CT?

is it beneficial for using single core of CT for metering and left all other cores useless or multi core CT for protection as well metering together ?

Can i know how many cores of CT have by these numbers ?

Hi neduetKK,

Please click here, which contains a lot of useful information close to your question.. Also, don't miss this if you need more about the basics of CTs.

Hope this help!!

I would like to also add what nikolay said in working with CTs you don't want to have open CTs to happen since it will raise the secondary voltage experienced by the CT that is enough to melt destroy the CT itself or worst propagate to a nearest equipment.