What are the advantages and applications of rogowski coil?

What is a Rogowski Coil?

The Rogowski coil is defined as an electrical device that is used to measure alternating current (AC). It is also used to measure the high-speed transient, pulsed current or sinusoidal current. The name Rogowski coil was named after the German physicist Walter Rogowski.

A Rogowski coil is an evenly wounded coil with N number of turn and constant cross-section area A. There is no metal core in a Rogowski coil.

The end terminal of the coil is returned through the central axis of the coil to another end. Therefore, both terminals are at the same end of the coil.

This entire assembly wrapped around the current-carrying conductor whose current we need to measure.

Advantages of Rogowski Coil

The advantages of Rogowski coils include:

1. It can respond to fast-changing currents.

2. The second terminal of the coil is returning to the first terminal. And it makes an open circuit coil. So, there is no danger of opening of the secondary coil.

3. The air is used as a medium. There is no magnetic core is used. So, there is no question of saturation of the core.

4. In this coil, temperature compensation is simple.

5. In order to keep output current constant, the AC current transformer (CT) needs to increase the number of secondary turns for large currents. Hence, for equal rating, the size of the Rogowski coil is small compared to a conventional current transformer.

6. It is available in two types; flexible as well as rigid.

Applications of Rogowski Coil

Rogowski coils are used for current monitoring in precision welding systems, arc melting furnaces, or electromagnetic launchers. They are also used in short-circuit testing of electric generators and as sensors in protection systems of electrical plants. Another field of usage is the measurement of harmonic current content, due to their high linearity.