The current transformer DC immune is used to detect AC currents wherever DC offsets exist. The current sense transformers create a voltage when current flows. They are mainly made for detecting AC currents in a circuit. So with a DC bias, the AC measurement can distort.

DC immune CTs are capable of measuring AC and DC component with high accuracy

So even though it has intrinsic high phase displacement, it has an excellent accuracy to satisfy class 0.5 smart meters in addition to measuring multi harmonics in the high accuracy. The characteristics are the supreme linearity throughout the whole dynamic current range and very low current loss.

The Applications of DC immune current transformer are:

High end DC immune electronic energy meters
Measurement of DC components in the AC line

The features are

• Excellent linearity & precision

• Good performance in DC factor

However, do you know how does a DC Immune current Transformer Core work ?

TRANSMART CORE designs and manufactures a series cores only for DC immune CT.  It is a composite core with Nanocrystalline materials and Amorphous material.  The Nanocrystalline material is with very high permeability up to 150000. So it is very sensitive and provide high accuracy of the Current Transformer.  But the Nanocrystalline core is easy to get saturated because the saturation flux density (Bs) of Nanocrystalline is 1.25 Tesla.  While the Bs of Amorphous material is 1.56 Tesla and it is an ideal combination of Nanocrystalline material.

The composite core with Nanocrystalline and Amorphous enjoys the advantage of high permeability as well as the high saturated flux density.  It is the best core solution for Current Transformer DC Immune.

Below are the typical standard sizes TRANSMART manufactures for DC immune CT:

Customized specifications and sizes are available.