Purpose of Current Transformer

Current transformers work by stepping down the electrical current in a circuit to a lower level, making it suitable for measuring with an ammeter or other measuring instrument. The current transformer is essentially a transformer that has a primary winding, which is connected to the current-carrying conductor, and a secondary winding that is connected to the measuring instrument. The secondary winding has fewer turns than the primary winding, which steps down the current.

One of the primary applications of current transformers is to measure the electric current in the power transmission and distribution systems. The measurement is critical for monitoring the load on the power system, ensuring that the system operates within its limits, and detecting any faults that may occur. Current transformers are also used to measure the current in high-voltage transmission lines, which may carry currents in the thousands of amperes.

Another application of current transformers is to provide protection to measuring instruments and other equipment. In power systems, high voltages can be harmful to instruments, leading to their failure or damage. By using a current transformer to isolate the instrument from the current-carrying conductors, the instrument is protected from the high voltage levels that may occur in the system. In addition, current transformers are used in relays that protect power equipment from short circuits and overloads.

Current transformers also play a critical role in metering the electrical energy consumed by customers. In this application, the current transformer is used to step down the current in the circuit, making it easier to measure with a meter. The meter is then used to calculate the total electrical energy consumed by the customer, which is used to bill them.