EN IEC 61869 Measuring Transformers

The “EN IEC 61869 Measuring Transformers” standard, developed by the International Electrotechnical Commission (IEC) and later published as a European standard within the scope of harmonization efforts, consists of the following sub-sections published under the same title:

• The “EN IEC 61869-1 Part 1: General requirements” standard applies to newly manufactured measuring transformers with a nominal voltage higher than 1 kV AC or 1,5 kV DC, equipped with an analog or digital secondary signal for measurement, protection, and control purposes, with nominal frequencies between 15 Hz and 400 Hz, or designed for DC applications.

A bushing-type current transformer, although it does not have a primary insulation level for itself, is typically installed in a system with a nominal voltage of at least 1 kV AC or at least 1,5 kV DC and therefore falls within the scope of this standard.

The EN IEC 61869-1 standard is a product family standard and covers only general requirements. The product standard for each type of measuring transformer consists of this standard and its associated specific product standard. This standard includes requirements for error limits for both analog and digital secondary signals. Other specifications for the digital interface of the measuring transformer are found in the EN IEC 61869-9 standard.

• The standard “EN IEC 61869-2 Part 2: Additional requirements for current transformers” applies to newly manufactured inductive current transformers intended for use with electrical measuring devices or electrical protection devices with nominal frequencies between 15 Hz and 100 Hz.
• The standard “EN IEC 61869-3 Part 3: Additional requirements for inductive voltage transformers” applies to new inductive voltage transformers for use with electrical measuring devices and electrical protection devices at frequencies between 15 Hz and 100 Hz. Specific requirements for three-phase voltage transformers are not included in this standard, but to the extent relevant, the requirements here apply to these transformers, and several references are made to them.

All transformers must be suitable for measurement purposes, but some types may also be suitable for protection purposes. Transformers used for both measurement and protection purposes must comply with all clauses of this standard.

• The standard “EN IEC 61869-4 Part 4: Additional requirements for combined transformers” applies to newly manufactured combined transformers intended for use with electrical measuring devices and electrical protection devices operating at frequencies between 15 Hz and 100 Hz. The requirements and tests of this standard cover the current and inductive voltage transformers necessary for combined measuring transformers, in addition to the requirements and tests of EN IEC 61869-1, EN IEC 61869-2, and EN IEC 61869-3 standards.
• The standard “EN IEC 61869-5 Part 5: Additional requirements for capacitor voltage transformers” applies to new single-phase capacitor voltage transformers connected between line and ground for system voltages of at least 72,5 kV at power frequencies between 15 Hz and 100 Hz. These are designed to provide low voltage for measurement, control, and protection functions.

The capacitor voltage transformer may or may not be equipped with carrier frequency accessories for powerline carrier frequency applications at carrier frequencies between 30 kHz and 500 kHz. Basic requirements for coupling capacitors and capacitor dividers are defined in the IEC 60358 standard. Transmission requirements for coupling devices for the powerline carrier system are defined in the IEC 60481 standard.

The measurement application includes both indicator measurement and income measurement.

• The standard “EN IEC 61869-6 Part 6: Additional general requirements for low-power measuring transformers” is a product family standard and covers additional general requirements only for low-power measuring transformers used in alternating current or direct current applications with nominal frequencies between 15 Hz and 100 Hz (medium voltage, high voltage, and very high voltage). This product standard is based on EN IEC 61869-1 in addition to the relevant product-specific standard.

The EN IEC 61869-6 standard does not cover the specifications for the digital output format of measuring transformers. This standard defines errors that may occur in both analog and digital output situations. Other features of the digital interface for measuring transformers are included in the EN IEC 61869-9 standard as an implementation of the IEC 61850 series of standards, which detail the layered substation communication architecture.

• The standard “EN IEC 61869-7 Part 7: Specific requirements for electronic voltage transformers” is a product standard and covers additional requirements for low-power voltage transformers with both passive and active technologies in AC applications with nominal frequencies between 15 Hz and 400 Hz and nominal voltages above 1 kV. A low-power voltage transformer may incorporate any arrangement of electrical, electronic, optical, magnetic, or other technologies. For analog secondary signals, this standard specifies the nominal secondary voltage. For digital secondary signals, this standard refers to the EN IEC 61869-9 standard.
• The standard “EN IEC 61869-8 Part 8: Specific requirements for electronic current transformers” is a product standard covering additional requirements for electronic current transformers used in AC applications with nominal frequencies between 15 Hz and 400 Hz and system voltages above 1 kV. The product standard for electronic current transformers consists of EN IEC 61869-6 and its specific requirements, in addition to the EN IEC 61869-1 standard.

Electronic current transformers may incorporate any electrical, optical, or magnetic technology arrangement, provided they include electronic devices. Current transformers containing passive surge protection devices are not considered electronic current transformers. For analog secondary signals, this standard specifies the nominal secondary voltage. For digital secondary signals, this standard refers to EN IEC 61969-9.

• The standard “EN IEC 61869-9 Part 9: Digital interface for measuring transformers” is a product family standard applicable to measuring transformers with digital output. The product standard consists of this standard and the relevant product-specific standards in the EN IEC 61869 series, in addition to EN IEC 61869-1 and EN IEC 61869-6 standards.

This standard defines the requirements for digital communication of measuring transformer measurements. It is based on the IEC 61850 series, the application guide for digital interface to measuring transformers using IEC 61850-9-2, and relevant sections of the IEC 60044-8 standard, which is replaced by this standard. The IEC 61588 standard includes additional improvements, including network-based time synchronization.

• The standard “EN IEC 61869-10 Part 10: Additional requirements for low-power passive current transformers” is a product standard and covers only the additional requirements for low-power passive current transformers. The product standard for low-power passive current transformers includes EN IEC 61869-1, EN IEC 61869-6, and this standard along with specific requirements.

This standard applies to newly manufactured low-power passive current transformers with analog output for use with electrical measuring devices or electrical protection devices having a nominal frequency between 15 Hz and 100 Hz. This standard covers low-power passive current transformers used for measurement or protection, and multi-purpose low-power passive current transformers used for both measurement and protection.

This standard covers the accuracy requirements for low-power passive current transformers for use with electrical measuring instruments. It also covers the accuracy requirements for low-power passive current transformers for use with electrical protection relays, and in particular, for protection types where the primary requirement is to maintain accuracy up to several times the nominal current. If necessary, the transient accuracy of low-power passive current transformers during fault situations is also given in this standard.

• The standard “EN IEC 61869-11 Part 11: Additional requirements for low-power passive voltage transformers” is a product standard and covers only additional requirements for low-power passive voltage transformers. The product standard for low-power passive voltage transformers consists of EN IEC 61869-1, EN IEC 61869-6, and specific requirements in conjunction with this standard.

This standard applies to newly manufactured low-power passive voltage transformers with analog output and nominal frequencies between 15 Hz and 100 Hz, intended for use with electrical measuring devices or electrical protection devices. This standard covers low-power passive voltage transformers used for measurement or protection, and low-power passive voltage transformers used for both measurement and protection.

• The “EN IEC 61869-13 Part 13: Self-Contained Combining Unit (SAMU)” standard is a product standard and covers additional requirements for self-contained combining units used only for AC applications with nominal frequencies between 15 Hz and 100 Hz. The digital output format specification is not included in this standard; this is addressed in the EN IEC 61869-9 standard as an implementation of the IEC 61850 standard, which specifies the power grid communication architecture.

This standard covers self-contained coupling units with standardized analog inputs provided by measuring transformers conforming to relevant product standards, and aims to convert them to digital outputs compliant with the EN IEC 61869-9 standard. Other input and output types are outside the scope of this document.

Cybersecurity requirements are outside the scope of this standard and are addressed under the IEC 62351 series.

• The standard “EN IEC 61869-14 Part 14: Additional requirements for current transformers for DC applications” provides all the requirements specific to current transformers to be used in DC applications, regardless of the technology used. The output signal can be analog or digital.

This standard applies to newly manufactured current transformers used for measurement, protection, or control applications in DC power systems with a nominal voltage above 1,5 kV. The general configuration of a single-pole low-power measuring transformer is described in the EN IEC 61869-6 standard. Current transformers designed for current measurement in the transistor arm of a VSC valve are not covered by this standard.

• The standard “EN IEC 61869-15 Part 15: Additional requirements for voltage transformers for DC applications” provides all the requirements specific to voltage transformers to be used in DC applications, regardless of the technology used. The output signal can be analog or digital.

This standard applies to newly manufactured voltage transformers used for measurement, protection, or control applications in DC power systems with a nominal voltage above 1,5 kV. It covers both active voltage transformers and passive voltage dividers used for measurement, control, and protection. The general configuration of a single-pole low-power measurement transformer is described in the EN IEC 61869-6 standard.

• The “EN IEC 61869-99 Part 99: Glossary” standard contains a glossary of specific terminology and definitions used in the field of measuring transformers across various parts of the series. Unless otherwise specified, all periodic electrical quantities in this standard should be understood as RMS values.

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