New Industry Products

Rogowski Coils for Measure up to 300,000A for Smart Grid Applications

December 03, 2019 by Paul Shepard

In response to the need for improvements in electrical parameters measurement support for the expanding smart grid, LEM announces the development of the ARU Rogowski coils range to measure current up to 300,000A ac with accuracy class 0.5.

The ARU range achieves IEC 61869-10 class 0.5 without the need for additional components such as resistors or potentiometers to calibrate the coil, which can drift over time. The range benefits from ‘Perfect Loop’ technology, a unique patented coil clasp that eliminates the inaccuracy caused by sensitivity to the position of the conductor inside the loop.  This technology provides an innovative, robust and fast ‘Twist and Click’ closure.

Compared to the previous series of LEM Rogowski coils (ART), the ARU range can be installed outdoors as all models are compliant with UV, water, dust and ice resistance standards. The range has ruggedized material to endure extreme environments (-40°C to +80°C operating temperature range). An internal shield also provides protection against external fields, improving accuracy and optimizing performance for small current measurements.

The ARU series provides the same ease of installation as existing split-core current transformers, but with the benefits of being thinner and more flexible.

Featuring aperture diameters of 70-, 125-, 175-, 250- and 300-mm, the ARU current sensors can be mounted very quickly - regardless of the chosen dimension - by simply clipping on to cables for measurement. Contact with the cable is not necessary, while the ARU models ensure a high level of safety and feature a highly rated insulation voltage (1000V Cat III PD2 - reinforced).

The ARU range allows the coil disconnection to be detected by a security seal passed through a specially designed slot, making it applicable for use with metering devices. All sensor models can be used in applications requiring a protection degree up to IP68.

The ARU series achieves accuracy class 0.5 and completes the LEM product portfolio for ac current measurement. LEM is dedicated to future distribution network applications while offering innovative and high-quality solutions for measuring electrical parameters into the smart grid.

The smart grid is in the middle of a radical transition, as millions of electric vehicles have hit the roads and terawatts of renewable energy capacity are installed in our grids. The smart grid currently needs smarter equipment that can provide reliable integration of intermittent renewable energies and distributed energy resources.

LEM improves smart grid applications by supporting electrical parameter measurements for control room automation, remote monitoring and the sharing of real-time equipment data. Typical applications are distribution automation for fault detection, isolation and restoration, grid monitoring (e.g. intelligent substations), protection and safety, distribution transformer monitoring, distribution automation for voltage control and power quality.

Covered by LEM’s five-year warranty, ARU series current sensors are CE marked and conformed to the IEC 61869 standard series.