Often the specified take-off point for measuring current in a hot power line is located in a bus or cable duct where the clearance around the primary conductor is too small to install a rigid split-core current transformer. Moving the take-off point to a different location may not be practical. An alternative solution would be to install a CT that is flexible enough to be installed in tight spaces and has the accuracy and stability of a magnetic split core. Such a solution exists in the Flexible Split-Core CT manufactured and distributed by Flex-Core, Inc.
The Flexible Split-Core CT consists of a secondary winding of copper wire around a directional silicon steel core, all encapsulated in silicone rubber. The flexible silicon steel core can be opened and twisted by hand like a metal spring to manipulate the core in a tight space until it surrounds the primary cable or bus. Installation is quick and easy.
The two halves are snapped together and held in placed by a metal latch. Once in place the Flexible CT operates like a conventional rigid-core CT.
Advantages of the Flexible Split-Core Current Transformer: It is simple, quick and easy to install; a sure favorite of field installers; It can be installed live in a tight space without shutting down the power line; Output is a low AC current directly proportional to the primary current. No electronic calibration or signal processing is required; The rated output current can be either 1A or 5A, standard for metering instruments; No external power or batteries are required; It provides 1% accuracy for a wide range of CT ratios and sizes; Accuracy is not affected by the path of the primary conductor through the aperture; It is ideal for long-term accurate measurement applications such as power metering and protective relay sensing.
Flex-Core, Inc. supplies the only flexible split-core CT available on the market today. It is available in a range of current ratios and sizes with either a circular or rectangular aperture. The circular model is suitable for cable conductors; the rectangular model fits busbars.
One model is rated for outdoor use on power lines and provides 1% accuracy for current ratios of 1000/5 to 6000/5.
For more information, visit: https://www.flex-core.com.