What is the main purpose of a current transformer?

Apr 02,2025

Editer: Sherry

The main purpose of a current transformer (CT) is to safely scale down high alternating currents (AC) to standardized, lower levels that can be accurately measured by instruments or used to activate protective relays.

What is current transformer?

A current transformer is a specialized type of transformer designed to measure alternating current (AC) safely and accurately by stepping down high primary currents to lower, standardized secondary currents. 

Key Features

Current Reduction: current transformer step down high primary currents to a manageable secondary current, enabling safe measurement with standard ammeters or energy meters.

Electrical Isolation: They isolate the high-voltage primary circuit from the low-voltage secondary circuit, protecting operators and equipment from dangerous voltages.

Measurement: current transformer ensure accurate proportional scaling and phase relationship of currents, critical for power monitoring, energy billing, and system diagnostics.

Protection: By detecting abnormal currents, CTs trigger protective relays to isolate faulty circuits, preventing equipment damage and improving grid reliability.

A Current Transformer monitors the electrical current in a circuit by generating a proportional alternating current in its secondary winding. Widely utilized globally, CTs play a critical role in measuring high-voltage power grid currents, ensuring accurate and safe monitoring through electromagnetic induction principles.

In summary, current transformers are vital for safe, accurate current measurement and reliable power system protection, bridging high-power circuits and low-voltage control systems.