What is current transformer accuracy class?

1.Current transformer accuracy class definition

Current transformers (CTs) are vital components in power systems, used to measure and protect against overcurrent. The accuracy class of a current transformer is a key parameter that defines the accuracy in converting primary current to secondary current under specified conditions.

The accuracy class of a current transformer refers to the allowable error limit under specified conditions. It is expressed as a percentage of primary rated current. The lower the accuracy class, the higher the accuracy of the current transformer.

2.Current transformer accuracy class level (0.1,0.2,0.5,1)

Current transformer accuracy classes are usually defined according to international standards (such as IEC 61869-2) to ensure consistent standards worldwide. IEC 61869-2 is applicable to newly manufactured inductive current transformers for use with electrical measuring instruments and/or electrical protective devices having rated frequencies from 15 Hz to 100 Hz. Accuracy classes are expressed as a percentage between secondary currents and primary currents percentage error. The following are common current transformer accuracy grade levels and their specific contents:

0.1 level:

Percent error: 0.1%.

Scope of application: Mainly used for high-precision measurement and metering applications, such as electric energy measurement and precision instruments.

Features: Provides the highest level of accuracy and is often used in situations where measurement requirements are very stringent.

0.2 level:

Percent error: 0.2%.

Scope of application: Suitable for measurements that require high accuracy but do not require 0.1 level, common in industrial and commercial fields.

Features: Provides high accuracy and is suitable for applications with high measurement requirements.

0.5 level:

Percent error: 0.5%.

Scope of application: For protection and metering applications where accuracy requirements are relatively low.

Features: Provides lower accuracy and is suitable for general protection and monitoring applications.

Level 1:

Percent error: 1%.

Scope of application: Mainly used in protective applications where accuracy requirements are relatively low.

Features: Provides relatively low accuracy, often used in applications such as protective relays where high accuracy is not a primary concern.

3.IEC 61869-2:2012 CT Accuracy Standards Introduction

The IEC 61869-2 standard is a standard issued by the International Electrotechnical Commission (IEC), which specifically covers the performance and test methods of current transformers. Since the specific content of the IEC standard is relatively detailed and complicated, it cannot be displayed in full here. However, I can provide some examples of specific topics and details that may be included in the IEC 61869-2 standard to demonstrate the breadth of its content.

Design requirements for current transformers:

Defines the structural and dimensional requirements for current transformers to ensure their suitability for specific power system applications.

Calibration Tests:

Includes tests that current transformers should undergo during calibration to verify their accuracy under various load conditions.

Magnetic Tests:

Specifies methods for testing current transformers under different magnetic field conditions to ensure that their magnetic response meets the requirements.

4. Temperature Characteristics:

The performance requirements of current transformers at different temperatures are described to ensure their stable operation under various environmental conditions.

5. Dynamic Characteristics:

Specifies the response characteristics of current transformers under changing current conditions, including response time and overload capability.

Environmental adaptability and protection level:

Defines the adaptability requirements of current transformers to humidity, vibration, pollution and other environmental factors, as well as the corresponding protection levels.

7. Performance Confirmation:

Includes specific methods for verifying and validating the performance of current transformers to ensure that they meet standard requirements in practical applications.

8. Documentation requirements:

Specifies the documentation that manufacturers should provide, including technical specifications, user guides, and performance reports, to facilitate the correct use and maintenance of current transformers.

Terms and definitions:

Terms and definitions used in the standard are listed in detail to ensure that all parties have a consistent understanding of the terms used in the standard.

Please note that these examples are only intended to illustrate the topics that may be covered; in fact, the specific content of the IEC standard may be more detailed and specialized. For the complete IEC 61869-2 standard text, it is recommended to refer to the official document released by the IEC. For more details, please click here to view.

4. What is Blue Jay CT accuracy class

Bluejay’s current transformers exhibit high precision and performance in many aspects and comply with international standards (IEC 61869-2). The following are the advantages of Bluejay current transformers:

Level of accuracy: Most of Bluejay’s current transformers have accuracy ratings of 0.5% and 0.2%, which means they can convert large currents from high-voltage circuits or low-voltage circuits into the small currents required by instruments and relay protection devices. Provides highly accurate measurements.

Comply with international standards (IEC 61869-2):

Bluejay’s current transformers comply with the IEC 61869-2 standard issued by the International Electrotechnical Commission, which certifies that its products meet globally recognized standards in design, manufacture, and performance.

Compact, convenient, and easy to install:

These current transformers are compact and easy to install and are suitable for use in various power systems and industrial automation environments, providing users with more flexibility and convenience.

Non-contact measurement:

The use of non-contact measurement technology greatly reduces the difficulty of installation and maintenance, providing users with a more convenient experience.

High measurement accuracy:

Bluejay’s current transformers have highly accurate measurement capabilities and can accurately measure the magnitude of current, ensuring the reliability of system data.

Effective isolation, quick response

The current transformer effectively isolates the measured current loop and the measurement circuit, improving the stability and safety of the system.

The fast response to current changes enables Bluejay’s current transformer to monitor and feedback on changes in current signals in real-time, ensuring the timeliness and sensitivity of the system.

Multiple output methods:

Bluejay’s current transformers provide a variety of output methods, including analog signal output, digital signal output, or communication interface output, to meet the needs of different users and the flexibility of system integration.

Overall, Bluejay’s current transformers not only excel in accuracy and performance, but also feature easy installation and multiple output modes, making them ideal for power systems, industrial automation, and electronic equipment monitoring.