Reset time in ANSI/IEC TCC curves
Reset time in ANSI/IEC TCC curves
(OP)
Some modern relays have a "Reset Time" for ANSI or IEEE and IEC inverse-time overcurrent curves. I understand the reset time is to emulate the disk type relays for the disk to return its zero position. My question is how does the reset time in the modern relays affect the TCC curves so as to the coordination?






RE: Reset time in ANSI/IEC TCC curves
On the other hand, every relay has, and has always had, a reset time. It may be less than a cycle, or it could be seconds, but there is a reset time none the less.
RE: Reset time in ANSI/IEC TCC curves
RE: Reset time in ANSI/IEC TCC curves
The second and subsequent trips in a reclosing sequence require reset be considered unless the only devices picking up for the fault are all instantaneous reset. You can find papers on fuse/recloser coordination that provide considerable detail. But if you don't coordinate reset as well as tripping characteristics you can find the "wrong" device clearing the fault.
RE: Reset time in ANSI/IEC TCC curves
David Castor
www.cvoes.com
RE: Reset time in ANSI/IEC TCC curves