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I am not sure why you wish to model saturation in your current transformer (normally you design to stay far away from that condition), but to do so, you will need core information: ID, OD and width (to get the cross sectional area and length) and the core material (to get the magnetic parameters Bs, Br, Hc).

analogspiceman

Thank you for your reply.

Yes we want to avoid saturation, but we are using the Current Transformer in two modes, for Energy Harvesting and Measurement. To this end we are changing the load it is connected to between the Modes and also switching in varying Burden resistance values.

Hence we would like to try to model the behaviour across a wide range of Primary currents to see the effect and to make sure that we understand what is happening and whether saturation becomes an issue. Also we need to understand the effect of a wide range of operating temperatures....

I have asked the manufacturers if they can supply the relevant details for the model, but so far, they do not seem to be able to give me anything more than the basic details and a test result excitation curve!

Thanks and Regards

Henry Kafeman

Hello Henry Kafeman.
The primary winding of the current transformer comprises a single turn. The current transformer is loaded by a small impedance in magnitude (relative). The consequence of this effect strong demagnetization. Therefore, the effect of magnetic saturation of the core needs huge currents.

Bordodynov.

29.07.2016, 14:46, "4vl7aujnwrex7ropketfjd7le5afsie4zyue7rcb@... [LTspice]" <ltspice@...>:

Bordodynov and analogspiceman

If you could please direct Email me at HKafeman@..., then I can give you some more details of the CT, etc.

One can make a reasonable guess about the CT core dimensions from the data sheet, but it is not clear what the material is.? High quality CTs use tape-wound nickel-iron cores to keep magnetizing current to a minimum, but your CT has a split core, which probably introduces enough of an air gap that they might use ordinary transformer steel, since it is less expensive and magnetizing current would be dominated by the gap.? However, the difference still matters because you care about saturation and nickel-iron has only about half the saturation level of regular transformer steel (the core losses are lower, too).

It is easy to guess your application, you are most likely using MOSFETs to time multiplex the output of the CT between normal current sensing and supplying power for the current sense circuitry.? No doubt you are wondering how the build up of magnetizing current will affect the accuracy of the sensed signal and how much power you get with a relatively low duty cycle in power mode.