Has anyone experience a 489 relay tripping on differential when the setting is turned off? I can test the ground fault pick ups but once i got to the phase overcurrent I cant get past the differential unlatched trip even though the setting has been set off while bench testing.
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Jonathan,
Are you certain that differential is blocking you? Did you remember to “Save” your settings so it was sent to the relay? Did you turn the setting to OFF? Unlatched still causes the contact to operate and drop out at the pickup. For some reason, I remember experiencing something like this a long time ago - maybe 10 years ago. I think it had to do with another setting that was enabled that I missed. Maybe offline O/C or something like that.
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It was a bad relay after all. When we swapped for a new relay and upoaded the settings from the original it didnt do it again.
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Nice. 95% of the time it is human error. It’s always a nice mental “win” when it turns out to be faulty equipment. Nice work!
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