under Additional Settings. If a trip is desired in case of intermitting reverse power, the maximum time
interval that may pass between two pickup impulses must be set here, if it is supposed to be interpreted as a
continuous pickup.
Delay Time
For generator applications, the following applies: If reverse power without emergency tripping is used, a
corresponding time delay must be implemented to bridge any short reverse power states after synchronization
or power swings subsequent to system faults (e.g. 3-pole short circuit). Usually, a time delay 5013 T-SV-
OPEN of approx. 10 s is set.
In case of faults causing an emergency tripping, the reverse power protection performs a short-time delayed
switchoff subsequent to the emergency tripping via an oil-pressure switch or a position switch at the emer-
gency trip valve. Before tripping, it must be ensured that the reverse power is only caused by the missing drive
power at the turbine side. A time delay is necessary to bridge the active power swing in case of sudden valve
closing, until a steady state active power value is achieved. A time delay 5014 T-SV-CLOSED of about 1 to 3 s
is sufficient for this purpose, whereas a time delay of about 0.5 s is recommended for gas turbine sets. The set
times are additional delay times not including the operating times (measuring time, dropout time) of the
protective function. Please note that averaging over 16 periods is executed during "precise" measuring proce-
dures; the operating time is thus respectively higher. This is recommended when used as reverse power
protection for generators, this is recommended (default setting address 5016 Type of meas. = accurate).
In system applications the delay time depends on the type of application and should overlap with the awaited
grading times. The time is important T-SV-OPEN (address 5013). The time T-SV-CLOSED (address 5014) is
usually not required in these cases and set to ∞. As high precision of the active power measurement is usually
not required here, address 5016 Type of meas. = fast can be set, thus enabling also short tripping times.
This parameter can only be altered in DIGSI under Additional Settings.
If a delay time is set to ∞, not trip is caused by this time, the pickup by reverse power is however indicated.
Settings
Addresses which have an appended “A” can only be changed with DIGSI, under “Additional Settings”.
The table indicates region-specific presettings. Column C (configuration) indicates the corresponding secon-
dary nominal current of the current transformer.
Addr.
Parameter C Setting Options Default Setting Comments
5001 REVERSE POWER OFF
ON
Block relay
OFF Reverse Power Protection
5011 P> REVERSE 1A -3000.00 .. -0.85 W -8.70 W P> Reverse Pickup
5A -15000.00 .. -4.25 W -43.50 W
5012 Pr pick-up -17.000 .. -0.005 P/SnS -0.050 P/SnS Pick-up threshold reverse
power
5013 T-SV-OPEN 0.00 .. 60.00 sec; ∞ 10.00 sec Time Delay Long (without
Stop Valve)
5014 T-SV-CLOSED 0.00 .. 60.00 sec; ∞ 1.00 sec Time Delay Short (with
Stop Valve)
5015A T-HOLD 0.00 .. 60.00 sec; ∞ 0.00 sec Pickup Holding Time
5016A Type of meas. accurate
fast
accurate Type of measurement
2.12.3
Functions
2.12 Reverse Power Protection
SIPROTEC 4, 7UT6x, Manual 227
C53000-G1176-C230-5, Edition 09.2016
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