Setting Notes; Settings - Siemens SIPROTEC 4 7UT6 Series Manual

Setting Notes

2.15.2
General
The application of overvoltage protection is only possible in 3-phase protected objects. Furthermore, it is a
prerequisite that the device is connected to a three-phase voltage transformer set.
Overvoltage protection is only effective and accessible if address 153 OVERVOLTAGE was set to Enabled
during configuration of the protection function (Section
At address 5301 OVERVOLTAGE the overvoltage protection ON or OFF can be set. Furthermore, the command
can be blocked if the protective function is enabled (Block relay).
Pickup Values, Times
Address 5318A VALUES serves to specify the measured quantities used by the protection feature. Setting U-
ph-ph evaluates the phase-phase voltages. This is not influenced by displacement voltages that occur during
ground connections or earth faults at a certain distance from the grounding point. The setting U-ph-e of the
phase-earth voltage reflects the actual insulation damage against earth and can also be used in an earthed
starpoint. This parameter can only be set with DIGSI under Additional Settings. Note that the setting values
for the voltages always refer to the phase-phase voltages, even though the measured values phaseearth have
been selected, in other words, U-ph-e evaluates √3 × phase-earth voltages.
The settings of the voltage threshold and the timer values depend on the type of application. Stage U> records
stationary overvoltages. It is set to approx. 5 % above the maximum stationary operating voltage that is
expected in operation. If the overvoltage protection is assigned to one side of the main protected object or the
three-phase busbar, the pickup value must be set as reference value under address 5312 U>, e.g. 1.20. When
assigned to a measuring location, the value of phase-phase voltage must be set under address 5311 U> in
Volt , e.g. 132. V at U
The corresponding delay time T U> (address 5313) should amount to a few seconds so that short-term over-
voltages do not result in a trip.
The U>> stage is provided for high overvoltages of short duration. Here, an correspondingly high pickup value
is set, e.g. 1.3 to 1.5 times the rated voltage. If the overvoltage protection is assigned to one side of the main
protected object or the three-phase busbar, the pickup value must be set as reference value under address
5315 U>>, e.g. 1.30. When assigned to a measuring location, the value of phase-phase voltage must be set
under address 5314 U>> in Volt , e.g. 130. V at U
For the delay T U>> (address 5316) 0.1 s to 0.5 s are sufficient.
In generators or transformers with voltage regulator, the settings also depend on the speed with which the
voltage regulator regulates voltage variations. The protection must not intervene in the regulation process of
the faultlessly functioning voltage regulator. The two-stage characteristic must therefore always be above the
voltage time characteristic of the regulation procedure.
All setting times are additional time delays which do not include the operating times (measuring time, dropout
time) of the protective function. If a delay time is set to , this does not result in a trip, however, the pickup is
indicated.
Dropout Ratio
The drop-out ratio can be adjusted to the operating conditions at address 5317 DOUT RATIO den Betriebsbe-
dingungen angepasst werden. Diese Einstellung ist nur mittels DIGSI unter Weitere Parameter mögli. This
parameter can only be altered in DIGSI under Additional Settings.
2.15.3

Settings

Addresses which have an appended "A" can only be changed with DIGSI, under "Additional Settings".
Addr. Parameter
5301 OVERVOLTAGE
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
= 110 V (120 % of 110 V).
N sec
Setting Options
OFF
ON
Block relay
2.1.3 Functional Scope).
= 100 V.
Nsec
Default Setting Comments
OFF Overvoltage Protection
Functions
2.15 Overvoltage Protection
237