LEM, the market leader in providing innovative and high quality solutions for measuring electrical parameters, is pleased to announce the development of the Rogowski coils range to measure current up to 300,000 A 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 with the previous LEM Rogowski coils ART, the ARU range can be installed outdoors as the models are compliant with UV, water, dust and ice resistance standards. The range has also ruggedized material to be durable in extreme environments (wide operating temperature range up to -40 to +80oC). Moreover, an internal shield is provided to protect against external fields, improving accuracy and optimising 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.
Whatever the chosen dimension – 70, 125, 175, 250 & 300-mm diameter for the aperture – the ARU can be mounted very quickly by simply clipping on to the cable to be measured. Contact with the cable is not necessary, while the ARU models ensure a high level of safety as well as provide a high rated insulation voltage (1000 V 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 useful when used with a metering device. They can be used in applications requiring a protection degree up to IP 68.
The models include an accuracy class 0.5 and complete the LEM product portfolio for the AC current measurement. LEM is dedicated to future distribution network applications and offers 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 hit the roads and Terawatts of renewable energy capacity are installed in our grids. Smarter equipment is needed for the Smart Grid, providing reliable integration of intermittent renewable energies and distributed energy resources. LEM improves the grid by measuring electrical parameters, allowing control rooms to automate, monitor remotely and share real-time equipment data. Typical applications are Distribution Automation for Fault Detection, Isolation & Restoration, Grid Monitoring (e.g. Intelligent substations), Protection & Safety, Distribution Transformer Monitoring, Distribution Automation for Voltage Control and Power Quality.
The ARU series current sensors are CE marked and conformed to the IEC 61869 standard series, as well as being covered by LEM’s five-year warranty.