CT class X 1

[ZapSib]

This is a IEC world background question.
Class X CT were firstly define in British Standard 3938 now obsolete.
High Z scheme ( such as REF) are still use, therefore the need for such CT.

Such CT call for Vk, Rct and Imag requirements.

IEC 60044-1 define class PX with the same requirements.
Inside 60044-6 is found class TPS with similar datas.

People still abuse class X while dealing with such CT.

Should I refer to PX or TPS class when dealing with REF protection scheme?

Regards.

 

[RRaghunath]

Class PX I guess.
Class TPS CT is for special transient performance requirement, I understand. I haven't come across this class in actual use till date.
Class PX is the traditional Class PS or Class X CT and is relevant for high impedance differential / REF protection etc.

 

[ZapSib]

raghun,
thank you for the reply.
I went though standard more carrefully this time and your answer make sense.