138 Bus Diff - Different CT accuracy class
138 Bus Diff - Different CT accuracy class
(OP)
When using differential bus protection, one of the TX's CT accuracy calss is different than the others (0.3B1.8 @800:5)
How does this affect protection? During fault conditions it will saturate at different times? the other CTs are
http://files.engineering.com/getfile.aspx?folder=b...
How does this affect protection? During fault conditions it will saturate at different times? the other CTs are
http://files.engineering.com/getfile.aspx?folder=b...






RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class
My other question is. Has anyone ever seen that "XXXX" rating next to it? im not sure what that means?
RE: 138 Bus Diff - Different CT accuracy class
David- Can you please explain a bit more? I hadn't realized a metering rated CT could be used for any kind of differential.
RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class
More generally if you can avoid saturation on a low-impedance scheme unequal, even radically unequal, saturation characteristics don't matter. On a high-impedance scheme they absolutely matter. There's also the case where it only saturates for in-zone faults (mostly transformer diff) that the saturation becomes less of an issue.
RE: 138 Bus Diff - Different CT accuracy class
As part of commissioning the transformer, there may have been CT ratio/saturation tests conducted. If not, the tests are pretty easy to run next time the transformer is out for maintenance.
RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class
RE: 138 Bus Diff - Different CT accuracy class