Shaft current protection in Easergy MiCOM P345

[ManuelTrebilcock]

Hello community,

I need to implement shaft current protection in a P345. As far as I understand, it´s just an overcurrent with very small values where fundamental and third harmonic are dominant. I am thinking that CT sensitive input and SEF function can be used for this purpose.

Has anyone had some experience with this protection function and may give me some advice? Am I right?

Best regards,

Manuel Trebilcock 

[Jinlei_Xing]

Please pay attention that the minimum current setting in P354 SEF is 5mA. Usually the current setting for shaft current protection is very small, such 1 ~ 5mA. Besides, an alarm stage with a time delay, such as 5~10s,  is suggested, to avoid the possible unnecessary trip. 

[ManuelTrebilcock]

Thank you for your reply Jinlei,

Is there anything we can do like using a rogowski coil with the right integrator as a method to measure the shaft current or perhaps an additional device that only realizes that function? 

What solution have you implemented?

Best regards,