AC current sensors to class accuracy 0.5 are simple to install

February 09, 2017 // By Graham Prophet
Swiss sensor maker LEM has developed the ART, an upgraded Rogowski-type current sensor that is non-contacting, galvanically isolated and installs as a loop around the primary conductor.

The sensor measures current of up to 10,000A (10 kA) AC and beyond with Class Accuracy 0.5. The ART achieves IEC 61869 Class 0.5 accuracy without the need for additional components such as resistors or potentiometers, which can drift over time. The ART employs LEM's “Perfect Loop” technology, a patented coil clasp that eliminates the inaccuracy caused by sensitivity to the position of the conductor inside the loop as well as providing an innovative, robust and fast “Twist and Click” closure.

 

An internal shield is provided as standard to guard against external fields, improving accuracy and optimising performance for small current measurements. The ART series provides the same ease of installation as existing split-core transformers, but is thinner and more flexible, and comes in dimensions of 50, 70, 125, 175, 200 & 300 mm diameter for the aperture. Contact with the cable is not necessary, and the ART ensures a high level of safety as well as providing a high rated insulation voltage (1000 V Cat III PD2 - reinforced).

 

The ART also allows disconnection of the coil to be detected through the use of a security seal passed through a specially designed slot, for use with a meter. It can be used in applications requiring a protection degree up to IP 67.

 

This Class Accuracy 0.5 ART updated version completes the LEM City product solutions for the AC current measurement dedicated for future Smart Cities offering innovative and high quality solutions for measuring electrical parameters in Smart Grids and Industry 4.0.

 

LEM; www.lem.com and in relation to Smart Cities, www.lemcity.com