If the reverse power protection has been assigned to one side of the machine to be protected, the pickup
value of the reverse power can be set as relative value (relevant to machine rated power) under address 5012
Pr pick-up. As the reverse power is a negative active power, it is set as a negative value (a positive setting
value cannot be set).
However, if the reverse power protection must be set in ampere (secondary) during operation, the reverse
power must be recalculated as a secondary value and set under address 5011 P> REVERSE. This is the case if
the reverse power protection has been assigned to a measuring location and not to a side of the main
protected object, thus usually in system applications. The following applies:
[flexfkn-ansprechwert-250204-he, 1, en_GB]
with
P
sec
secondary power
U
Nprim
primary rated voltage of the voltage transformer (interlinked)
U
Nsec
secondary nominal voltage of the voltage transformers (phase-to-phase)
I
Nprim
primary rated current of the current transformer
I
Nsec
secondary rated current of the current transformer
P
prim
primary power
If the primary power is referred to the rated power of the main protected object, it needs to be converted:
[primaer-nennleistung-schutzobjekt, 1, en_GB]
with
active power referenced to the rated apparent power of the protected object
S
NObj
Nominal apparent power of protected object
Example:
Generator
5.27 MVA
6.3 kV
Current transformer 500 A/5 A
Voltage transformer 6300 V/100 V
perm. reverse power 3 % = 0.03
In case of setting in Watt secondary address 5012
Pr pick-
up =
- 0.03
In case of setting in Watt secondary address 5011
Pr pick-
up =
Pickup Seal-in Time
Intermitting pickups are delayed to the set minimum time by means of the pickup seal-in time under address
5015 T-HOLD. Usually, these are not required and set to 0.00. This parameter can only be set with DIGSI
Functions
2.12 Reverse Power Protection
226 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
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