Voltages Description
V1
main
Positive-sequence value of the main voltage
Pickup
If the voltage difference between each 2 of 3 continuous sampling points is over 8 % Vrated of the plant, the
supervision stage picks up.
Voltage Supervision
For the Voltage-comparison supervision function, the following 2 connection types are allowed:
•
Phase-to-ground
The phase-to-ground voltages are used for the voltage-difference comparison.
•
Phase-to-phase
The phase-to-phase voltages are used for the voltage-difference comparison.
NOTE
The 2 ph-to-ph volt. + VN and 2 ph-to-ph voltages connection types are not allowed.
Voltage-Failure Indication
For different connection types, the indications are different.
•
Phase-to-ground
You can get the voltage-failure information from the output signals
Main-voltage failure
and
Ref.-voltage failure
.
•
Phase-to-phase
– If one phase is influenced, the phase information is indicated.
– If more than one phase is influenced, the phase-to-phase information is indicated.
Take the main voltage transformer for example. You can determine the faulty phase with the
following table.
Determination Criteria
Calculated Result
(|vAB(n)ref.| - |vAB(n)main|) - 8 % Vrated > 0 > 0 < 0
(|vBC(n)ref.| - |vBC(n)main|) - 8 % Vrated < 0 > 0 > 0
(|vAC(n)ref.| - |vAC(n)main|) - 8 % Vrated > 0 < 0 > 0
Failure Information Phase A is failed. Phase B is failed. Phase C is failed.
Release Voltage
If the main positive-sequence voltage or the reference positive-sequence voltage is between 50 % Vrated and
130 % Vrated, the function is released.
Selection Invalid
An invalid measuring-point selection results in the following:
•
The voltage measured values are displayed as Failure.
•
The validity of the voltage measured values is set to Invalid.
•
The indication
Health
is set to Alarm.
•
The indication
Selection invalid
becomes true.
Supervision Functions
9.3 Supervision of the Secondary System
SIPROTEC 5, Overcurrent Protection, Manual 1269
C53000-G5040-C017-8, Edition 07.2017
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