High Accuracy or High Burden requirements in CT's (Using Multiple Turns)

July 10 2020, by Daniel Rehe, 1 min reading time

Class Accuracy, VA Rating (Burden) and Physical Size of Current Transformers are all related. 

High Accuracy or High Burden requirements in CT's

Class Accuracy, VA Rating (Burden) and Physical Size of Current Transformers are all related. 

See Blog on CT Cable Losses

In practice smaller sized CT's reduce the design scope of VA Rating of CT's, also higher accruacy CT;s also reduce the available burdne for a given CT case design.

Several field applications require high VA Rated CT's for example

- Power Factor Coreection Controllers

- Power Quality Analysers

- Long Metering Cable Runs (also in combination wth the above)

Several devices can be connected to a single CT as long as the combined burden, including teminal connections, is below the CTs maximum burden.

In many cases increasing the cable size is not practical and there is another optiosn which could solve ths issue. 

You can have multiple turns through a larger rated, larger sized CT to boost the bruden rating. for exampel for 250 Amp measurement, typically ythe burdne is 2.5VA, you could use a 1000 Amp CT 10VA with 4 turns and you will be abel to run the cable 4 times the lenght for the same accruacy. 

If you have any questions feel free to contact our sales team 

Our range of CT's can be found via the below links

• Split Core CT's
• Solid Core CT's
• Split Core CT's with Process Outputs
• Solid Core CT's with Process Outputs

See our Blog on Current Transformer Types 

• Cable Diameter to mm^2 Conversion Chart

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