Rogowski coils are innovative devices used for measuring alternating current (AC) or rapidly changing electrical currents. Unlike traditional current transformers, Rogowski coils don’t have a magnetic core. Instead, they rely on Faraday’s law of electromagnetic induction to measure current.
The MRC & NRC series is a new generation of flexible Rogowski coil (Rogowski® coil) current sensors, which are especially suitable for measuring in combination with portable devices. They have different sizes to cope with different conductors. The new generation of coils strengthens the shielding layer and greatly reduces the influence of external magnetic fields.
Advantages:
- Excellent linearity
- Wide dynamic range
- Not damaged by large overloads
- Excellent degree of rejection to the external current conductor
- No danger from open-circuited secondary
- Zero power consumption
- Small position error
- Soft and light, easy to install
- Suitable for outdoor use
- Long-term stability
- Wide dynamic range
- IP67 protection level
Applications:
- Smart meter
- Rectifier current measurement
- Power quality analysis
- Motor overload/short circuit protection
- Current monitoring of power frequency and intermediate frequency welding machine
- Medium and high voltage switchgear protection system
- Remote Terminal Unit (RTU)
- Synchronous Phasor Measurement Unit (PMU)
- Current measurement on the secondary side of the electric furnace
What is a Rogowski coil?
Rogowski coils have been used for the detection and measurement of electric currents since 1912. They are based on a simple principle: an “air-cored” coil is placed around the conductor in a toroidal fashion and the magnetic field produced by the current induces a voltage in the coil. The voltage output is proportional to the rate of change of current. This voltage is integrated, thus producing an output proportional to the current. By using precision winding techniques, especially developed for the purpose, the coils are manufactured so that their output is not influenced by the position of the conductor within the toroid, and to reject interference from external magnetic fields caused, for example, from nearby conductors. Basically, a Rogowski coil current measuring system consists of a combination of a coil and conditioning electronics.
They can be used in similar circumstances to CTs (current transformers) but for many applications they have considerable advantages:
