A current transformer
(CT) is an electrical device used to measure the flow of electric current in a high-voltage circuit.
CTs are used in a variety of applications, including power generation, transmission, and distribution, to monitor the flow of electrical energy and to provide information about the health and performance of the electrical system. CTs are also commonly used in protection and control systems, where they are used to detect fault conditions and trigger protective devices.
There are several types of CTs, including window-type, bar-type, and wound-type CTs. The type of CT used in a particular application depends on factors such as the magnitude of the electrical current, the required accuracy of the measurement, and the environmental conditions.
Overall, current transformers are essential components in modern electrical power systems, providing critical information about the flow of electrical energy and helping to ensure the reliability and stability of the electrical grid.
A current transformer works
by converting the high current in the primary circuit to a lower, more manageable level of current in the secondary circuit. This is done by wrapping a conductor, such as a wire, around a magnetic core. The high current in the primary circuit flows through this conductor, generating a magnetic field that is proportional to the current.
The secondary circuit of the current transformer is connected to a load, such as a meter or a relay, that requires a low-level current. This secondary circuit is wound around the magnetic core, with the number of turns in the secondary winding being much higher than the number of turns in the primary winding.
As the magnetic field generated by the primary current passes through the magnetic core, it induces a current in the secondary winding. This induced current is proportional to the primary current, but at a reduced magnitude due to the ratio of turns in the primary and secondary windings.
By connecting a load to the secondary winding, the current transformer allows the flow of high-level current in the primary circuit to be measured safely and accurately. This is useful in applications where it is not possible or practical to directly measure the high current in the primary circuit, such as in power generation, transmission, and distribution systems.