Current Transformer (CT)

With the continuous growth in electrical energy consumption across residential, industrial, and commercial sectors, the reliable development and operation of power transmission and distribution networks have become one of the essential requirements of the country’s electricity industry. Achieving this goal requires not only infrastructure expansion but also the utilization of high-accuracy, highly reliable, and stable measurement and protection equipment. Among these, instrument transformers—particularly Current Transformers (CTs)—are considered some of the most critical components in high-voltage substations.

A Current Transformer is responsible for converting high network currents into standardized and safe values (typically 1 or 5 amperes), enabling the measurement, monitoring, and protection of high-voltage equipment without directly connecting measurement devices to the power network. In addition to providing electrical isolation between the primary power circuit and secondary equipment, CTs ensure the accuracy and reliability required for the proper operation of measurement and protection systems.

In a power substation, almost all measurement, control, and protection systems rely on current information provided by Current Transformers. These devices play a fundamental role in the proper operation of the following systems:

• Energy measurement systems and revenue meters (Revenue Metering)
• Measurement equipment for current, power, energy, power factor, and power quality
• Differential protection relays
• Overcurrent protection relays
• Earth fault protection relays
• Distance protection relays
• Protection systems for busbars, circuit breakers, generators, transformers, and transmission lines

The performance accuracy of these systems depends on the technical specifications of Current Transformers, including accuracy class, protection class, instrument security factor (FS), accuracy limit factor (ALF), burden capacity, and other parameters. Proper selection of these characteristics ensures the reliable operation of protection systems under both normal operating conditions and fault scenarios.

According to statistics provided by Tavanir Company, more than 320,000 instrument transformers are currently in operation across the country’s power network. Any failure or outage of these devices can lead to incorrect protection system operation, reduced measurement accuracy, the loss of service availability of at least one bay, and ultimately power outages and significant economic losses. Therefore, manufacturing quality, factory acceptance tests, and proper maintenance of these components are of critical importance.

In addition to supplying various types of Current Transformers, including measurement CTs, protection CTs, multi-core CTs, and special-purpose CTs, this company provides comprehensive engineering services to customers, including technical specification review, equipment selection and adaptation, manufacturing supervision, acceptance testing, installation, commissioning, and technical support. These services ensure that the equipment operates with the highest level of reliability within power networks.