UNE-EN IEC 61869-10:2020

The scope of the IEC 61869-1 is applicable with the following additions:This standard is a product standard and covers only additional requirements for low-power passive current transformers. The product standard for low-power passive current transformers is composed by the IEC 61869-1, in addition with IEC 61869-6 and this standard with specific requirements.This International Standard is applicable to newly manufactured low-power passive current transformers with analogue output for use with electrical measuring instruments or electrical protective devices having rated frequencies from 15 Hz to 100 Hz.Clause 5.6.1001 covers the accuracy requirements that are necessary for low-power passive current transformers for use with electrical measuring instruments.Clause 5.6.1002 covers the accuracy requirements that are necessary for low-power passive current transformers for use with electrical protective relays, and particularly for forms of protection in which the prime requirement is to maintain the accuracy up to several times the rated current. If required, the transient accuracy of low-power passive current transformers during fault is also given in this clause.This standard covers low-power passive current transformers used for measurement or protection and multipurpose low-power passive current transformers used for both measurement and protection.Sensors are based on passive technologies e.g. air-core coils and iron-core coils with integrated shunt used as a current-to-voltage converter (primary converter), without any active electronic components. This standard is not covering the air core coil with active integratorLow-power passive current transformers have analogue output only (for digital output or for technology using any kind of active electronic components refer to IEC 61869-8). Such low power passive current transformers may include the secondary signal cable (transmitting cable). Principle of operation of low-power passive current transformers using air-core coils (Rogowski coils) are given in Annex 10B and principle of operation of iron-core coils with integrated shunt are given in Annex 10C.According to a general block diagram given in Figure 601 (IEC 61869-6), the low power passive current transformers do not use an active primary converter (i.e. without any active electronic component); therefore there is no need for primary power supply. Additionally, neither the secondary converter nor the secondary power supply is used.The general block diagram of a low-power passive current transformer is given in Figure 1001.The applied technology decides which part is necessary for the realization of a low-power passive current transformer, i.e. it is not absolutely necessary that transmitting cable or primary converter described in Figure 1001 are included in the low-power passive current transformer. Rogowski coil solution considers only air-core coil as primary sensor and transmission cable as transmitting system. In this technology, primary converter is not considered. In case of IC-LPCT solution, ferromagnetic-core coil is considered as primary sensor, burden resistance connected directly to the coil outputs works as a primary converter and transmission cable is a transmitting system.