GB/T 20840.8-2007 in English

《GB/T 20840.8-2007互感器 第8部分：电子式电流互感器》由TC222（全国互感器标准化技术委员会）归口，主管部门为中国电器工业协会。
GB/T 20840的本部分适用于新制造的模拟量输出的电子式电流互感器，它具有模拟量电压输出或数字量输出，供频率为15Hz至100Hz的电气测量仪器和继电保护装置使用。

Scope

This part applies to newly manufactured electronic current transformers, which have analog voltage output or digital output, and are used by electrical measuring instruments and relay protection devices with a frequency of 15Hz to 100Hz. The accuracy requirements listed in Chapter 12 apply to electronic current transformers for electrical measuring instruments. The accuracy requirements listed in Chapter 13 are applicable to electronic current transformers for relay protection devices, especially those protection methods whose main requirement is to maintain accuracy when the current reaches many times the rated current. When required, the transient accuracy of electronic current transformers during power system faults is also listed in this chapter. Electronic current transformers for both measurement and protection purposes shall comply with all the provisions of this standard and are referred to as multi-purpose electronic current transformers. This transformer technology can use optical devices with electronics, air core coils (with or without built-in integrators) or iron core coils with built-in shunt resistors as converters of electrorheological voltage, which can be used alone or with electronics . For analog outputs, electronic current transformers may include secondary signal cables. The technical examples of electronic current transformers using hollow wire diagrams and core coils with built-in parallel resistors are listed in Appendix D. For digital output, this section adopts electronic transformers to electrical measuring instruments and electrical devices as point-to-point links (see Appendix E). In order to ensure the compatibility of this point-to-point link with the entire substation communication system, thereby allowing data exchange between all types of substation devices, some additions were made. These establish the link-layer mapping of what is called a point-to-point serial link. Bus communication is under consideration. This mapping allows devices from different manufacturing units to be used interoperably. This section neither specifies a specific implementation or product, nor does it limit various implementations and interfaces of computer systems. This section specifies the externally visible functions of various implementations, and the requirements to which these functions are subject.