Do you know the difference between current transformer and transformer?

Current transformers (CTs) and transformers differ fundamentally in their operating conditions, functional purposes, and design parameters: The secondary side of a current transformer must not be open-circuited, and its primary current is determined by the external load; it is dedicated to current measurement and protection. In contrast, the secondary side of a transformer must not be short-circuited, and its primary current is determined by the secondary load; it is primarily used for voltage transformation and power transfer.

Current transformer: The secondary side must be closed (approximately short-circuited). An open circuit will generate high voltage, endangering safety and causing core saturation.

Transformer: The secondary side can be operated with an open circuit, but short circuits are strictly prohibited; otherwise, overcurrent will damage the equipment.

Current transformer: The primary current is independently determined by the primary circuit load current and is independent of the secondary circuit impedance.

Transformer: The primary current is jointly determined by the secondary load current and the primary voltage, and varies with the secondary load.

Current Transformer: Its core function is current transformation (e.g., converting 100A to 5A), used for measuring instruments, relay protection, and electrical isolation; it does not transmit electrical energy.

Transformer: Primarily responsible for voltage transformation and electrical energy transmission, such as step-up or step-down, serving power distribution.