The Following Settings Can Be Done For The Two Step Overvoltage Protection - ABB REB670 Applications Manual

1MRK 505 337-UUS -
8.2.3.5
Application manual

The following settings can be done for the two step overvoltage protection

ConnType: Sets whether the measurement shall be phase-to-ground fundamental value,
phase-to-phase fundamental value, phase-to-ground RMS value or phase-to-phase RMS
value.
Operation: Disabled/Enabled.
VBase (given in GlobalBaseSel): Base voltage phase to phase in primary kV. This voltage
is used as reference for voltage setting. OV2PTOV (59) measures selectively phase-to-
ground voltages, or phase-to-phase voltage chosen by the setting ConnType. The function
will operate if the voltage gets lower than the set percentage of VBase. When ConnType is
set to PhN DFT or PhN RMS then the IED automatically divides set value for VBase by
√3. When ConnType is set to PhPh DFT or PhPh RMS then set value for VBase is used.
Therefore, always set VBase as rated primary phase-to-phase ground voltage of the
protected object. If phase to neutral (PhN) measurement is selected as setting, the
operation of phase-to-earth over voltage is automatically divided by sqrt3. This means
operation for phase-to-ground voltage over:
> ×
V (%) VBase kV ( ) / 3
EQUATION1713 V2 EN
and operation for phase-to-phase voltage over:
> ×
Vpickup (%) VBase(kV)
EQUATION1992-ANSI V1 EN
The below described setting parameters are identical for the two steps (n = 1 or 2).
Therefore the setting parameters are described only once.
Characteristicn: This parameter gives the type of time delay to be used. The setting can be
Definite time, Inverse Curve A, Inverse Curve B, Inverse Curve C or I/Prog. inv. curve.
The choice is highly dependent of the protection application.
OpModen: This parameter describes how many of the three measured voltages that should
be above the set level to give operation. The setting can be 1 out of 3, 2 out of 3, 3 out of 3.
In most applications it is sufficient that one phase voltage is high to give operation. If the
function shall be insensitive for single phase-to-ground faults 1 out of 3 can be chosen,
because the voltage will normally rise in the non-faulted phases at single phase-to-ground
faults. In subtransmission and transmission networks the UV function is mainly a system
supervision function and 3 out of 3 is selected.
Pickupn: Set operate overvoltage operation value for step n, given as % of VBase. The
setting is highly dependent of the protection application. Here it is essential to consider the
Section 8
Voltage protection
(Equation 75)
(Equation 76)
237