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A measurement transformer is a device used in an electrical system to measure and convert current and voltage from a high input level to a low output level, or vice versa, while maintaining the value of the measured parameter. Measurement transformers include current transformers and voltage transformers, which are used to measure current and voltage in power systems. This device has a general structure including a magnetic circuit, primary coil and secondary coil, and is often divided into voltage transformers and current transformers depending on the purpose of use.
This overview of measurement transformers provides an overview of transformer types and their basic principles, while emphasizing their important role in measuring current and voltage in systems. electricity.
Overview of measurement transformers
Overview of measurement transformers
Measurement transformers include current transformers and voltage transformers.
Diagram of a simple electrical system and main electrical equipment is as follows:
Basic principle of measurement transformer:
The general structure of a measurement transformer includes: Magnetic circuit, primary coil and secondary coil.
In there:
– For current transformers: Working in short circuit mode, the number of primary turns is much smaller than the number of secondary turns (n1
– For voltage transformers: Working in open circuit mode, the number of primary turns is much larger than the number of secondary turns (n1>n2).
Voltage transformers
– Most are single-phase voltage transformers.
– Secondary side standard voltage: 100/3 (V) or 100/√3 (V).
– Voltage transformers can be divided according to structure:
+ Inductive Voltage Transformer_IVT: Usually used for medium voltage levels
+ Capacitive Voltage Transformer (CVT): Usually used for high voltage levels
Or by insulation:
+ Oil-paper insulation (Oil-Paper)
+ Epoxy insulation
+ Gas- or Gas-Mixture insulation
Current transformer
– Secondary side standard current: 1A or 5A
– There are many ways to classify current transformers, basically there are the following types:
+ Wound current transformer (toroidal)
+ Ring current transformer (like ceramic pin current transformer)
+ Block current transformer (applied to cables and busbars)
Summary :
Measurement transformers are important devices used in electrical systems to measure and convert current and voltage from high input levels to low output levels, or vice versa, while maintaining the same value of the information. measurements.
Measurement transformers include current transformers and voltage transformers. Current transformers usually have a standard secondary current of 1A or 5A, and come in many forms such as wire wound, ring, and block, to suit specific applications in the power system.
Voltage transformers are usually single-phase voltage transformers, with a standard secondary voltage of 100/3 (V) or 100/√3 (V). In addition, they can be classified according to the insulation method such as oil-paper insulation (Oil-Paper), Epoxy insulation, or gas- or gas-mixed insulation (Gas- or Gas-Mixture).
Structurally, the measurement transformer consists of a magnetic circuit, a primary coil and a secondary coil. With a current transformer, the number of primary turns is much smaller than the number of secondary turns (n1 < n2), while with a voltage transformer, the number of primary turns is much larger than the number of turns. secondary (n1 > n2).