Siemens siprotec 7SA522, Руководство пользователя

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Functions
6-26
7SA522 Manual
C53000-G1176-C119-2
In some cases, however, a three-pole trip would be preferable for this fault scenario,
e.g. if the double-circuit line is located next to a large generator unit (Figure 6-14). This
is because the generator considers the two single-phase to ground faults as one dou-
ble-phase ground fault, with correspondingly high dynamic load on the turbine shaft.
With
SROHFRXSOLQJ
set to
:LWKIDXOWGHWHFWLRQ
, the two lines are
switched off three-pole, since each device picks up as with L1–L2–E, i.e. as with a
multi-phase fault.
Figure 6-14
Multiple fault on a double-circuit line next to a generato
r
Address
$ 7ULSSK)OW
determines that the short-circuit protection functions
perform only a single-pole trip in case of isolated two-phase faults (clear of ground),
provided that single-pole tripping is possible and permitted. This allows a single-pole
rapid automatic reclosure cycle for this kind of fault. The trip type can be set to
SROH
OHDGLQJSKDVH
or
SROHODJJLQJSKDVH
. The parameter is only available in ver-
sions with single-pole tripping. This setting can only be modified with DIGSI
®
4 under
“Additional Settings”. If this option is used, it must be born in mind that the phase
selection should be the same throughout the entire network and that it must be the
same at all ends of one line. More information on the function is also contained in Sec-
tion 6.17.3 Overall Fault Detection Logic of the Device. The default setting is
WULSOH
SROH
.
~
L1–E
L2–E