Rogowski Coil: A Powerful Assistant for Current Measurement

Rogowski coil, also known as current measurement coil or differential current sensor, is an important component in the field of current measurement. It is composed of a circular coil uniformly wound on a non-magnetic material, also known as a hollow coil due to the absence of an iron core.

The principle of measuring current with a Rogowski coil is based on Faraday's law of electromagnetic induction and Ampere's law of loop. When the measured AC current passes through the center of theRogowski coil along the axis, a changing magnetic field will be generated in the surrounding area of the annular winding. According to Ampere's Loop Law, the equation related to magnetic field strength can be derived; Combined with a series of formulas based on the law of electromagnetic induction, it can be deduced that the output voltage of the coil is directly proportional to the differential of the measured current. That is to say, as long as its output is connected to the integration circuit, a voltage signal proportional to the input current can be restored, achieving current measurement.

Rogowski coil has significant advantages. The measurement range is extremely wide, ranging from milliampere to megaampere; Good linearity, the output signal is linearly correlated with the measured current, easy to calibrate, and the measurement results are accurate; Wide bandwidth range, able to adapt to different frequency current measurements; There is no risk of secondary open circuit, strong overcurrent capability, and low power consumption; It can measure irregular conductors without damaging them during installation and is also lightweight.

In practical applications, Rogowski coils have shown great potential. In the field of relay protection, with fast response and high precision, abnormal currents can be detected in a timely manner to ensure the safety of the power system; In situations where the current signal is severely distorted, such as thyristor rectification, variable frequency speed regulation, and resistance welding, the true current situation can also be accurately restored. For example, in scenarios such as large-scale power equipment testing and current monitoring in industrial automation production, Rogowski coils play a crucial role in providing reliable current data support for the smooth progress of related work.