According to the technical experts at transformer tester manufacturer Demiks, voltage transformers, also known as potential voltage (PT or VT) and current transformers (CT), are key devices for measurement and protection in power systems. The following is a detailed description of them:

1. Voltage transformer (PT/VT)

Function: Convert high voltage to low voltage for use in measurement and protection equipment. The primary voltage of PT is usually very high, such as 6000V, 10000V, etc., while the secondary voltage is a standard value, such as 100V.

Features:

High insulation requirements: need to withstand high voltage.

Large load impedance: high load impedance and small current on the secondary side.

High accuracy requirements: high accuracy is required for measurement and protection.

Wiring method:

The primary side is connected in parallel to the high-voltage circuit.

The secondary side is connected to the measuring instrument or protection device.

Application: voltage measurement, energy metering, relay protection

2. Current Transformer (CT)

Function: Convert large current into small current for use in measurement and protection equipment. The primary current of CT can be adjusted as needed, common ones are 15A, 30A, 50A, etc., while the secondary current is usually the standard 5A.

Features: High insulation requirements: need to withstand high voltage.

Low load impedance: low load impedance and large current on the secondary side.

High accuracy requirements: high accuracy is required for measurement and protection.

Wiring method: The primary side is connected in series to the high-voltage circuit.

The secondary side is connected to the measuring instrument or protection device.

Application: Current measurement, energy metering, relay protection

3. Main differences

4. Summary

Voltage transformer: used to convert high voltage into low voltage, suitable for voltage measurement and protection.

Current transformer: used to convert high current into low current, suitable for current measurement and protection.

CVT is the abbreviation of Capacitor Voltage Transformer, which combines the characteristics of capacitor voltage divider and electromagnetic transformer, and is used for high voltage measurement and protection. CVT can accurately reflect the changes in system voltage and provide corresponding signals for protection and control systems.

The above content is published by demiks, please specify, demiks is a substation equipment manufacturer, specializing in the production of high-voltage tester, transformer tester, circuit breaker test equipment, relay tester, SF6 gas analyser, cable fault tester and other products, if you have power test testing needs, please feel free to contact demiks power science and technology limited company or send an email! Give us: contact@demikspower.com