IEC 61869-2 pdf download

IEC 61869-2 pdf download.Instrument transformers – Part 2: Additional requirements for current transformers
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC 61 869-1 :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 3.3.203 rated short-time thermal current I th maximum value of the primary current which a transformer will withstand for a specified short time without suffering harmful effects, the secondary winding being short-circuited [SOURCE: IEC 60050-321 :1 986, 321 -02-22] 3.3.204 rated dynamic current I dyn maximum peak value of the primary current which a transformer will withstand, without being damaged electrically or mechanically by the resulting electromagnetic forces, the secondary winding being short-circuited [SOURCE: IEC 60050-321:1986, 321-02-24] 3.3.205 rated continuous thermal current I cth value of the current which can be permitted to flow continuously in the primary winding, the secondary winding being connected to the rated burden, without the temperature rise exceeding the values specified [SOURCE: IEC 60050-321:1986, 321-02-25] 3.3.206 rated primary short-circuit current I psc r.m.s. value of the a.c. component of a transient primary short-circuit current on which the accuracy performance of a current transformer is based Note 1 to entry: While I th is related to the thermal limit, I psc is related to the accuracy limit. Usually, I psc is smaller than I th . 3.3.207 exciting current I e r.m.s. value of the current taken by the secondary winding of a current transformer, when a sinusoidal voltage of rated frequency is applied to the secondary terminals, the primary and any other windings being open-circuited [SOURCE: IEC 60050-321:1986, 321-02-32]