ABB RELION REX640, Техническое руководство, Страница: 605 / 1960

Figure 344: Operation timer characteristic of IFPTOC function when Operation
principle = “EF-current based” and Operating curve type = “Inverse time EN50522”.
Setting UTp multiplier is 2.0, Maximum earthing Ris = 10 ohms, EF current Str Val =
0.02*In (4 A), IDMT stage Min Op Tm = 100 ms and IDMT stage Max Op Tm = 5000
ms. Reduction factor = 1.0. Characteristics are according to standard EN50522.
Example 2c. Inverse time operation of IFPTOC, when
Operation principle = “EF-
current based” and
Operating curve type = “Inverse time EN50522” is illustrated in
Figure 345
. Start value for operation is set to be 0.06*In (6 A). IFPTOC is set to have
minimum operate time 100 ms and maximum operate time of 5000 ms. Setting
UTp
multiplier is 4.0 and setting Maximum earthing Ris is 10 ohms. Reduction factor =
1.0. For illustrating the operating speed requirement of protection, limits of earth
potential rise durations defined in standard EN50522 scaled into corresponding
earth-fault current requirements using the maximum earthing resistance R
Emax
(setting
Maximum earthing Ris) encountered in protected feeder are shown for
reference.
1MRS759142 F Protection functions
REX640
Technical Manual
605