The stage picks up when the measured voltage value falls below the pickup value Threshold × Pickup
factor.
Depending on the Measured value, the Threshold is set either as phase-to-phase quantity or as
phase-to-ground quantity.
With the Pickup factor parameter, you modify the pickup value. To avoid a long operate delay time after
pickup, Siemens recommends using the default value of Pickup factor.
Specify the Threshold (pickup threshold) and Pickup factor for the specific application.
Parameter: Pickup mode
•
Recommended setting value (_:101) Pickup mode = 1 out of 3
With the Pickup mode parameter, you specify whether the stage picks up when there is a lower threshold-
value violation in one measuring element (1 out of 3) or when there is a lower threshold-value violation in
all 3 measuring elements (3 out of 3).
Parameter Value Description
1 out of 3
Use this setting for protection applications or for monitoring the voltage
range.
Siemens recommends 1 out of 3 as the default setting. This reflects how
the function behaved in previous generations (SIPROTEC 4, SIPROTEC 3).
3 out of 3
Select this setting when using the stage to disconnect from the power
system (in the case of wind farms, for example).
Parameter: Pickup delay
•
Default setting (_:102) Pickup delay = no
The Pickup delay parameter is only available if you are using the current-flow criterion of the function
(parameter Current-flow criterion = on). If the current-flow criterion is deactivated, no pickup delay is
required.
With the Pickup delay parameter, you set whether pickup of the stage is to be delayed by approximately
40 ms or not. The delay avoids possible brief pickup of the stage when the circuit breaker opens.
Parameter Value
Description
no
Use this setting if you definitely do not want stage pickup to be subject to a
time delay in the event of a fault. This setting results in pickup and, where
applicable, tripping being performed as quickly as possible.
Note that switching procedures (opening of the CB) can result in brief
pickup of the stage, depending on the threshold-value settings for under-
voltage pickup and the current-flow criterion. To prevent unwanted trip-
ping, you must set a minimum tripping delay of 50 ms.
yes
Use this setting when switching procedures (opening of the CB) are not
permitted to result in stage pickup.
Note that pickup is delayed by approximately 40 ms. This delay is added to
the operate time.
Parameter: Charact. constant k, Charact. constant α, Charact. constant c
•
Default setting (_:103) Charact. constant k = 1.00
•
Default setting (_:104) Charact. constant α = 1.000
•
Default setting (_:105) Charact. constant c = 0.000
With the Charact. constant k, Charact. constant α, and Charact. constant c parameters,
you define the required inverse-time characteristic.
Protection and Automation Functions
6.29 Undervoltage Protection with 3-Phase Voltage
SIPROTEC 5, Overcurrent Protection, Manual 747
C53000-G5040-C017-8, Edition 07.2017
To Next Page
Loading...
