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Sepam Series 60 or 80 for Ground Differential Protection (ANSI 87GN). Can the 64REF protection function be used?
For installations with a generator where current sensors on both the 3 outgoing phase conductors and the neutral point conductor are available, the customer may wish to implement a Ground Differential (ANSI 87GN) protection function. The concept of this protection function is described in the attached image.
The Sepam user manuals do not mention the ANSI 87GN code specifically.
However, since the 87GN protection function is essentially comparing the Residual Current measured by the sum of the 3 phase conductors to the Residual Current measured by the neutral link current transformer, we can see that this is conceptually similar to the 64REF Restricted Earth Fault function.
As long as the 64REF CT sizing rules are respected, the Sepam Series 60 or 80 restricted earth fault protection function can be used to replace the 87GN function.
AEDL3
The Sepam user manuals do not mention the ANSI 87GN code specifically.
However, since the 87GN protection function is essentially comparing the Residual Current measured by the sum of the 3 phase conductors to the Residual Current measured by the neutral link current transformer, we can see that this is conceptually similar to the 64REF Restricted Earth Fault function.
As long as the 64REF CT sizing rules are respected, the Sepam Series 60 or 80 restricted earth fault protection function can be used to replace the 87GN function.
AEDL3
Released for:Schneider Electric Singapore
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