Siemens siprotec 7SA522 - Page 339

2.20 Function control and circuit breaker testing
339
7SA522 Manual
C53000-G1176-C155-3
These alarms can be allocated to LEDs or output relays. In the event of three-pole trip-
ping all three alarms pick up.
If single-pole tripping is possible, the protection functions generates a group signal for
the local displaying of alarms and for the transmission of the alarms to a PC or a
central control system, e.g. ´'LV7ULSS/µ, ´'LV7ULSS/µ, for single-pole
tripping by the distance protection and ´'LV7ULSSµ for three-pole tripping. Only
one of these alarms is displayed at a time. These alarms are also intended for the trip
command output to the circuit breaker.
Single-pole Trip-
ping after Two-
Phase Fault
Single-pole tripping for two-phase faults is a special feature. If a phase-phase fault
without earth
occurs in an earthed system, this fault can be cleared by single-pole trip
and automatic reclosure in one of the faulted phases, as the short-circuit path is inter-
rupted in this manner. The phase selected for tripping must be the same at both line
ends (and should be the same for the entire system).
The setting parameter 7ULSSK)OW (address ) allows to select whether this trip-
ping should be SROHOHDGLQJ, i.e. single-pole tripping of the leading phase, or
SROHODJJLQJ, i.e. single-pole tripping of the lagging phase. Standard setting is
SROH, i.e. three-pole tripping after two-phase faults (default setting).
Table 2-12 One-pole and three-pole trip depending on fault type
Type of Fault
(from Protection Func-
tion)
Parameter
Trip2phFlt
Output signals for trip
TRIP 1p. L1 TRIP 1p. L2 TRIP 1p. L3 Relay TRIP
3ph.
L1 (any) X
L2 (any) X
L3 (any) X
L1 E (any) X
L2 E (any) X
L3 E (any) X
L1 L2 3pole X
L1 L2 1pole leading Ø X
L1 L2 1pole lagging Ø X
L2 L3 3pole X
L2 L3 1pole leading Ø X
L2 L3 1pole lagging Ø X
L1 L3 3pole X
L1 L3 1pole leading Ø X
L1 L3 1pole lagging Ø X
L1 L2 E (any) X
L2 L3 E (any) X
L1 L3 E (any) X
L1 L2 L3 (any) X
L1 L2 L3 E (any) X
E(any) X