Current transformer wide bandwidth, SCT-013-000

Hello world,

This is my first post here so be nice ;-)

I'm looking for current transformer to measure current and some harmonics in the current. However I have not found any good current transformers that have a higher bandwidth than 400Hz. So with that CT I would not measure many harmonics in a 50Hz power system. Now I found a SCT-013-000 on ebay and the seller claims it's bandwidth is 150kHz. This sounds like chinese-specs to me but I have also found some test here on OEM that shows that SCT-013-000 goes over 2.5kHz...

Can anyone confirm SCT-013-000 true bandwidth and if it's possible to use it for harmonics measurement or suggest other current transformers that would be suitable to harmonic measurement.


Robert Wall's picture

Re: Current transformer wide bandwidth, SCT-013-000

Why do you need to go beyond the 50th harmonic? You should not be drawing harmonic current with any magnitude at those frequencies, it's certainly unsociable and quite possibly illegal, depending on where you live. If you are interested in device testing, then surely should you not be using test instruments designed for the purpose?

I too don't believe 150 kHz. When I did those measurements that I think you are referring to, I stopped at what seemed to be a ridiculously high frequency for normal purposes - certainly energy meters have no requirement to register at that frequency - and  I was already seeing a degree of roll-off.

You should be able to run your own test if you have a sufficiently high powered high bandwidth amplifier, signal generator and measuring equipment.

If you really need accurate measurements at those frequencies, it more than likely you will find you need to look at Rogowski Coils. Being air-cored these are naturally more suitable, but limited by the performance of the integrator and any subsequent buffer.


rajtantajtan's picture

Re: Current transformer wide bandwidth, SCT-013-000

Thank you for the answer Robert!

Well I don't need to go beyond the 50th harmonic but I was just wondering if the CT can be used to measure more than the claimed 400Hz which in fact your measurements confirms.

I have read a little about rogowski coil but they are quite expensive and needs integrator circuit but if I intended do measure fast transients I'm sure they would be perfect!

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