Functions
6-193
7SA522 Manual
C53000-G1176-C119-2
The impulse duration
(address
) is only significant when the
trip command must be transmitted to another item of plant, e.g. to the circuit breaker
at the opposite line end of the feeder. The impulse must ensure that the command is
reliably transferred (transmission time) and reliably executed by the other item of plant
(response time of this plant item).
Displacement
Voltage Stage
The displacement voltage stage can be switched
21
or
2))
separately under address
. In addition, this stage can also be selected to
$ODUP2QO\
i.e. the stage is in
service and also issues alarms, but no trip command is generated. The impulse is
however not suppressed. This protection function can be used for any other single-
phase voltage which is connected to the fourth voltage measurement input U
4
. (also
refer to Section 6.1.1 > “Voltage Transformer Connection”).
The settings of the voltage measurement and the timers depends on the type of appli-
cation. General guidelines can therefore not be given. Generally, with a sensitive set-
ting of
(address
), i.e. close to the expected operational values, not only
the delay time
(address
) must have a longer setting, but the reset ratio
(address
) must also be as large as possible. The presetting
is generally sufficient. This setting can only be modified with DIGSI
®
4 under “Addi-
tional Settings”.
Similar considerations apply if this voltage stage is used for a different voltage con-
nected to the measuring input U
4
.
When setting the voltage values please observe the following:
•
- If the U
en
-voltage of the set of voltage transformers is connected to U4 and if this
was already set in the power system data 1 (refer also to Section 6.1.1 > “Voltage
Transformer Connection”, U4 transformer =
), the device mul-
tiplies this voltage with the matching ratio Uph / Udelta (address
), usually with
1.73. Therefore the voltage measured is
√
3
.
U
en
= 3
.
U
0
.
When the voltage triangle
is fully displaced, the voltage will be
√
3-times the line voltage
.
•
- If any other voltage is connected to U4, which is not used for voltage protection,
and if this was already set in the power system data 1 (refer also to Section 6.1.1 >
“Voltage Transformer Connection”, e. g. U4 transformer =
or U4
), the device calculates the zero sequence voltage
according to the definition: 3
.
U
0
= IU
L1
+ U
L2
+ U
L3
I. When the voltage triangle is
fully displaced, the voltage will be the
√
3-times the line voltage
.
•
- If any other power-frequency voltage is connected to U
4
, which is used for voltage
protection, and if this was already set in the power system data 1 (refer also to Sec-
tion 6.1.1 > “Voltage Transformer Connection”, e. g. U4 transformer =
), this power-frequency voltage will be used for the voltage stages without
any further factors. This “zero sequence voltage protection” then is, in reality, a sin-
gle-phase voltage protection for the voltage at U
4
.
The impulse duration
(address
) is only significant when the
trip command must be transmitted to a different item of plant. The impulse must en-
sure that the command is reliably transmitted (transmission time) and reliably execut-
ed by the other plant item (response time of that plant item).
Содержание siprotec 7SA522
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