LEM announces two new coreless high-current sensors to support the renewable energy industry

     LEM has introduced two new coreless high current sensors that can accurately measure high DC currents ranging from 2kA to 42kA, without any limits caused by surge currents. The Open Loop Coreless Integral (OLCI) sensors have a wide opening that allows for precise measurement of high currents on large busbars. These sensors can handle high frequency applications with a bandwidth of up to 1MHz. In addition, they are considerably lighter, weighing just 80% of what open loop or closed loop current transducers weigh when operating in the same current measuring range. Furthermore, they are more cost effective compared to these transducers.

     LEM offers two variations of the new OLCI high current sensors: the FRS model, which can accommodate primary busbar openings of 104mm x 22mm, and the FL variant, which can handle openings up to 300mm x 100mm. Due to its split transducer design, the FL may be conveniently installed and connected to the busbar without the requirement of opening the busbar, thus simplifying the installation and maintenance process.

     The sustainability of the new sensors is derived from their potential to consume 85% less energy compared to similar closed loop sensors, resulting in a savings of up to 150 kilowatt hours (kWh) over the course of a year. The FRS sensor significantly decreases raw material costs and power losses by eliminating the need for a magnetic core, secondary copper winding, and instead using an integrated Rogowski coil and an array of Hall components.

     Although the busbar design and installation are uncomplicated, both sensors are manufactured using material that is completely recyclable when they reach the end of their lifespan. Simultaneously, by utilizing local supply chains inside Europe and employing 100% recyclable packaging, the sensors effectively reduce their carbon footprint in terms of product transit and distribution, especially considering the shortage of LEM operations.

     The new sensors are versatile and can be used in a variety of applications in the railway industry, wind turbines, hydrogen electrolysers, low-voltage and medium-voltage variable frequency drives, induction welding, and DC grid monitoring.

     The two new sensors from LEM provide a mix of exceptional precision and strong signal reliability, featuring a current output range of 4mA to 20mA. The Hall elements provide superior performance in terms of temperature drift, electric offset, and noise compared to open loop alternatives. Another advantage is the quick response time achieved by eliminating the low pass filter effect caused by Eddy currents in the magnetic core. The novel sensors are resistant to high rates of change of current (dI/dt) and high frequency signals. Their coreless measurement architecture allows them to maintain accuracy and functioning even in the presence of overcurrents. Furthermore, their unipolar power supply guarantees reduced power consumption and system expenses in comparison to conventional bi-polar power supplies.