What is current transformer and Rogowski coil

In the realm of electrical engineering and power systems, precision and accuracy in measurement are pivotal. Devices like Current Transformers (CTs) and Rogowski Coils serve as indispensable tools, offering insight into current flow within circuits, facilitating efficient monitoring, and ensuring safety in various applications.

Current Transformers (CTs)

What Are They? A Current Transformer is a type of instrument transformer designed to step down high currents to a standardized, manageable level for measurement and protection purposes.

It consists of a primary winding, which carries the high current being measured, and a secondary winding connected to measuring instruments or protective relays.

Functionality and Application CTs function based on electromagnetic induction. The primary current flowing through the flexible current transformer induces a proportionate current in the secondary winding, typically scaled down by a fixed ratio.

These scaled-down currents are then used for various purposes, such as ammeter readings, protective relaying, or feeding data to control systems in power grids, substations, industrial equipment, and other electrical systems.

Importance in Safety and Accuracy CTs play a critical role in safety by providing accurate readings without the need to directly measure high currents. They enable safer and more accessible monitoring of electrical systems, ensuring that equipment operates within safe limits and facilitating timely intervention during faults or abnormalities.

Rogowski Coils

What Are They? Rogowski Coils, named after the physicist Walter Rogowski, are flexible, air-cored coils used for measuring alternating current (AC). Unlike traditional CTs, Rogowski Coil do not have an iron core. Instead, they utilize a coiled conductor, often a flexible wire or cable, wound around the current-carrying conductor.

Functionality and Application Rogowski Coils function based on Faraday’s law of electromagnetic induction. When an AC current flows through the conductor surrounded by the coil, Current Sensor it induces a voltage in the coil proportional to the rate of change of the current. This induced voltage, when integrated over time, provides an accurate measurement of the current magnitude.

Advantages and Applications One of the primary advantages of Rogowski Coils lies in their flexibility and ease of installation compared to traditional CTs. They find applications in scenarios where space constraints or irregular-shaped conductors make CT installation challenging.

Rogowski Coils are used in power quality monitoring, energy management systems, xxxc and in scenarios requiring non-intrusive, accurate current measurements.


Current Transformers and Rogowski Coils stand as indispensable components in electrical measurement and monitoring.

While CTs excel in stepping down high currents for measurement and protection, Rogowski Coils offer flexibility and non-intrusive current measurement capabilities.

Together, these instruments play pivotal roles in ensuring the efficiency, safety, and reliability of electrical systems across various industries and applications.

Leave a Reply

Your email address will not be published. Required fields are marked *