Home > TECHNICAL FAQS > What is the difference between low-voltage current transformers and high-voltage current transformers?

What is the difference between low-voltage current transformers and high-voltage current transformers?

What is the difference between low-voltage current transformers and high-voltage current transformers?
Feb06, 2026

What is the difference between low-voltage current transformers and high-voltage current transformers?

 

Current transformer, abbreviated as (CT), is a device used for measuring alternating current. It converts large current into a smaller current through the principle of electromagnetic induction, making it convenient for measurement, protection and control. Low-voltage current transformers and high-voltage current transformers are mainly distinguished based on their working voltage levels. Low-voltage current transformers are typically used in power systems with an alternating voltage of 1000V (1kV) or below. High-voltage current transformers are used in ultra-high voltage power grids ranging from 1kV to 100kV.

Main differences comparison

Low Voltage CTHigh Voltage CT
Voltage LevelIt is typically applicable to low-voltage systems of 1kV and below (such as 0.4kV, 0.66kV).It is suitable for high voltage systems above 1kV (such as 10kV, 35kV, 110kV or even higher).
Insulation levelThe insulation requirements are relatively low, and dry insulation (such as epoxy resin casting or air insulation) is often used, with a low withstand voltage.High insulation requirements are required, and oil-immersed, SF6 gas insulation, or composite insulation are often used to withstand high voltage and prevent breakdown.
Structural designIt has a simple structure, small size, and light weight, and is usually a ring or rectangular iron core, making it easy to install.The structure is complex and the volume is large, which may include porcelain sleeves, oil tanks or gas chambers to ensure safe isolation.
ApplicationIt is widely used in low-voltage distribution cabinets, industrial control systems, metering instruments, and household appliance protection.It is widely used in high-voltage substations, transmission lines, and power plants for measurement, protection relays, and fault monitoring.
Safety and MaintenanceIt is easy to install and maintain, has low cost, and low risk.It has strict safety requirements, is complex to maintain, requires regular inspection of insulating oil or gas, and is costly.
Standards and SpecificationsIt complies with standards such as IEC 61869-2, but focuses on low-voltage safety.It complies with standards such as IEC 61869-2, emphasizing high-voltage insulation and shock resistance.

 

Inquiry Form