What is the role of current transformers?

• A. To increase voltage in high-current applications
• B. To measure current and produce a proportional secondary current
• C. To store current for later usage
• D. To filter out unwanted frequencies

Answer: (B)

Current transformers play a crucial role in electrical systems by measuring alternating current (AC) and producing a secondary current that is proportional to the primary current. This is essential for monitoring, metering, and protection purposes within electrical networks.

When AC flows through the primary winding of a current transformer, it generates a magnetic field. This magnetic field induces a current in the secondary winding, which can be used to provide accurate and safe measurements of high currents without needing to connect measuring devices directly to the high-power circuit. The scale of the transformation allows for high primary currents to be converted into safely measurable secondary currents, which can be displayed on meters or used by protective relay systems without risking damage to the measuring instruments.

This functionality is vital for ensuring that electrical systems operate efficiently and safely, allowing operators to monitor loads and detect faults.