What is the main purpose of a current transformer (CT)?

The main purpose of a current transformer (CT) is to measure the current flowing through a conductor. CTs are designed to produce a secondary current that is proportional to the primary current, allowing for safe measurement and monitoring of high currents in electrical systems. This is particularly useful as it enables technicians and engineers to gather necessary data for control, protection, and monitoring without directly connecting measuring devices to high voltage lines.

In practical applications, when the primary current flows through the CT, it induces a magnetic field, which then generates a secondary current in the windings of the transformer. This secondary current is at a much lower, manageable level and can be measured easily using standard ammeters or monitoring equipment.

While there are other components in electrical systems that serve to increase voltage, protect circuits, or provide power sources, the unique ability of current transformers to accurately measure current without directly engaging with high-energy conductors makes them indispensable for safety, efficiency, and accuracy in electrical installations.