Instrument Transformers

IEC 61869-14:2018 provides all requirements specific to current transformers to be used in DC applications (DCCTs), whatever the technology used. The output signal can be analogue or digital.
It is applicable to newly manufactured current transformers used for measuring, protection and/or control applications in DC power systems with a rated voltage above 1,5 kV.
The general configuration of a single-pole low-power instrument transformer is described in Figure 601 of IEC 61869-6:2016.
The DCCTs intended for current measurement in the transistor branch of the VSC valve (referred to as CT4a and CT4b in Figure 1403 and Table 1402) are not covered by this document, and will be considered in a future revision.
IEC 61869-14:2018 applies to current transformers intended to be used in DC applications with at least one of the following functions:
• measure DC current (with significant harmonics);
• withstand DC voltage.
Depending on the position on the DC system, different kinds of application exist, which are briefly described below, together with the approximate voltage or current wave shape.

IEC/TR 61869-102:2014(E) provides technical information for understanding the undesirable phenomenon of ferroresonance oscillations in medium voltage and high voltage networks in connection with inductive voltage transformers. Ferroresonance can cause considerable damage to voltage transformers and other equipment. Ferroresonance oscillations may also occur with other non-linear inductive components.

IEC TR 61869-100:2017(E) is applicable to inductive protective current transformers meeting the requirements of the IEC 61869-2 standard.
It may help relay manufacturers, CT manufacturers and project engineers to understand how a CT responds to simplified or standardized short circuit signals. Therefore, it supplies advanced information to comprehend the definition of inductive current transformers as well as their requirements.
The document aims to provide information for the casual user as well as for the specialist. Where necessary, the level of abstraction is mentioned in the document. It also discusses the question about the responsibilities in the design process for current transformers.

IEC 61869-10:2017 is a product standard and covers only additional requirements for low-power passive current transformers. The product standard for low-power passive current transformers comprises IEC 61869-1, together with IEC 61869-6 and this document with specific requirements.
This document is applicable to newly manufactured low-power passive current transformers with analogue output for use with electrical measuring instruments or electrical protective devices having a rated frequency from 15 Hz to 100 Hz.
This document 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 first edition of IEC 61869-10, together with IEC 61869-1, IEC 61869-6, IEC 61869-8 and IEC 61869-9, cancels and replaces the first edition of IEC 60044-8, published in 2002. This edition constitutes a technical revision.
The technical changes concern IEC TC 38's decision to restructure the whole set of stand-alone standards in the IEC 60044 series and transform it into a new set of standards composed of general requirements documents and specific requirements documents.

This International Standard is applicable to newly manufactured instrument transformers with analogue or digital output for use with electrical measuring instruments or electrical protective devices having rated frequencies from 15 Hz to 100 Hz. TC 38 decided to restructure the whole set of stand-alone Standards in the IEC 60044 series and transform it into a new set of standards composed of general requirements documents and specific requirements documents. This Standard is the first issue of this new series and can be regarded as a Product Family standard. It contains the general requirements for instrument transformers and shall be read in conjunction with the relevant specific requirements standard for the instrument transformer concerned.