https://docs.cntd.ru/document/1200120136
Кстати, см. рис. 203 в этом ГОСТ - по предыдущему обсуждению
... определения там переводили какие-то надмозги. Нагуглил оригинальный МЭК
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
(просто ТТ как обычно, нормируются по установившемуся режиму, у одного лимитируется остаточная намагниченность, у другого нет)
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).
(это типа выбрали с минимальным временем до насыщения, или как-то промоделили по осцилле, ТТ насыщается - тут не уточнено, но РЗА работает правильно, в одном случае остаточная намагниченность лимитируется, в другом нет, наверное авторы стандарта думают, что иногда и без ограничения прокатит)
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
(это выбрали, видимо, без насыщения вообще, в одном случае лимитирована остаточная намагниченность, в другом нет, авторы думют, что иногда это прокатит)
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
(Ts=0.06 с)
