A current transformer is a type of transformer used to determine the magnitude of electric current at high voltage. The inside of the current transformer consists of primary windings and secondary windings. The number of primary windings is very small, while the number of secondary windings is very large. The secondary winding section is connected to an electrical measuring instrument, namely an ammeter. The secondary section is also connected to the control circuit and protection relay. Current transformers consist of 2 types, namely current transformers (CT) and voltage transformers (VT).
- Current Transformer (CT)
A current transformer (CT) is an electrical device used to transfer electrical power from one circuit to another to change high current to low current without changing its frequency and achieve this by electromagnetic induction so that it can be used in measuring and protection equipment.
The uses of a current transformer are :
- Current Measurement
The first function of this tool is to measure the current flowing in a high-voltage circuit. This allows measuring equipment, such as an ammeter, to work safely at high currents without damaging the measuring equipment. - Protection
Current transformers are used in electrical protection systems. They detect currents that exceed a certain threshold and trigger a protection relay to break the circuit in the event of a fault or excess current. This helps protect equipment and prevent electrical hazards.
- Voltage Transformer (VT)
A voltage transformer (VT), also known as an induction voltage transformer, is an instrument transformer designed to obtain a voltage level (secondary voltage proportional to the primary voltage) used for measurement (meter) and protection. Voltage transformers, also often known as potential transformers, are usually divided into three types: electromagnetic, capacitor, and optical.
The function of a voltage transformer is :
- Voltage Transformation
Converts electrical voltage from a high level to a lower level or vice versa for efficient distribution throughout an industrial facility. - Voltage Adjustment
Allows adjustment of electrical voltage for special equipment that requires a specific voltage for optimal operation. - Power Control and Distribution
Facilitates efficient and reliable distribution of electrical power to various equipment and machines in a factory or industrial facility. - Voltage Transformer Working Mechanism
In an electrical transmission system that operates at high voltages, such as 132 kV or even higher, direct measurement becomes impractical or even dangerous.
Current Transformer & Voltage Transformer B&D is a small transformer created primarily for metering, protection signal triggers, and also as a power source to operate small equipment.
Current Transformer and Voltage Transformer from the B&D brand have one type, namely:
- Indoor CT & VT B&D are transformers specifically designed for medium voltage measurement and protection applications, indoor installation types. Available for voltages up to 36 kV; phase to neutral or interphase for VT; and block or ring types for CT. Indoor CT B&D are instrument transformers specifically designed to provide current in the secondary coil that is proportional to the current flowing in the primary coil. Indoor VT B&D is a type of instrument transformer connected in parallel. This transformer is designed to provide a negligible load on the supply being measured and has an accurate voltage ratio and phase relationship to allow accurate secondary measurements to be connected.
