1 Scope
This part of IEC 61869 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.
2 Normative references
Clause 2 of IEC 61869-1:2007 is applicable with the following additions: IEC 61869-1:2007, Instrument Transformers – Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC 61869-1:2007 apply with the following additions:
3.1 General definitions
3.1.201
current transformer
instrument transformer in which the secondary current, under normal conditions of use, is substantially proportional to the primary current and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connections
[SOURCE: IEC 60050-321:1986, 321-02-01]
3.1.202
measuring current transformer
current transformer intended to transmit an information signal to measuring instruments and meters
[SOURCE: IEC 60050-321:1986, 321-02-18]
3.1.203
protective current transformer
a current transformer intended to transmit an information signal to protective and control devices
[SOURCE: IEC 60050-321: 1986, 321-02-19)
3.1.204
class P protective current transformer
protective current transformer without remanent flux limit, for which the saturation behaviour in the case of a symmetrical short-circuit is specified
3.1.205
class PR protective current transformer
protective current transformer with remanent flux limit, for which the saturation behaviour in the case of a symmetrical short-circuit is specified
3.1.206
class PX protective current transformer
protective current transformer of low-leakage reactance without remanent flux limit for which knowledge of the excitation characteristic and of the secondary winding resistance, secondary burden resistance and turns ratio, is sufficient to assess its performance in relation to the protective relay system with which it is to be used
3.1.207
class PXR protective current transformer
protective current transformer with remanent flux limit for which knowledge of the excitation characteristic and of the secondary winding resistance, secondary burden resistance and turns ratio, is sufficient to assess its performance in relation to the protective relay system with which it is to be used
Note 1 to entry: An increasingly number of situations occur where low DC currents are continuously flowing through current transformers. Therefore, in order to stop the current transformer from saturating, current transformers with air gaps, but with the same performance as Class PX, are used.
Note 2 to entry: The air gaps for remanence reduction do not necessarily lead to a high-leakage reactance current transformer (see Annex 2C).
3.1.208
class TPX protective current transformer for transient performance
protective current transformer without remanent flux limit, for which the saturation behaviour in case of a transient short-circuit current is specified by the peak value of the instantaneous error
3.1.209
class TPY protective current transformer for transient performance
protective current transformer with remanent flux limit, for which the saturation behaviour in case of a transient short-circuit current is specified by the peak value of the instantaneous error
3.1.210
class TPZ protective current transformer for transient performance
protective current transformer with a specified secondary time-constant, for which the saturation behaviour in case of a transient short-circuit current is specified by the peak value of the alternating error component
3.1.211
selectable-ratio current transformer
current transformer on which several transformation ratios are obtained by reconnecting the primary winding sections and / or by means of taps on the secondary winding
