ABB Relion 670 Series Applications Manual page 209

1MRK 511 358-UUS A
VBase (given in GlobalBaseSel ): Base voltage phase-to-phase in primary kV. This voltage is used as
reference for voltage setting. UV2PTUV (27) measures selectively phase-to-ground voltages, or
phase-to-phase voltage chosen by the setting
gets lower than the set percentage of
the IED automatically divides set value for
PhPh DFT or PhPh RMS . Therefore, always set VBase as rated primary phase-to-phase voltage of
the protected object. This means operation for phase-to-ground voltage under:
<
V (%)
EQUATION1711 V1 EN-US
and operation for phase-to-phase voltage under:
Vpickup
EQUATION1991-ANSI V1 EN-US
The below described setting parameters are identical for the two steps (
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 , Prog. inv. curve . The selection is dependent on the
protection application.
OpModen : This parameter describes how many of the three measured voltages that should be
below the set level to give operation for step n. The setting can be
3 . In most applications, it is sufficient that one phase voltage is low to give operation. If UV2PTUV
(27) shall be insensitive for single phase-to-ground faults,
subtransmission and transmission networks the undervoltage function is mainly a system
supervision function and 3 out of 3 is selected.
Pickupn : Set operate undervoltage operation value for step n , given as % of the parameter VBase .
The setting is highly dependent of the protection application. It is essential to consider the
minimum voltage at non-faulted situations. Normally this voltage is larger than 90% of nominal
voltage.
tn : time delay of step n , given in s. This setting is dependent of the protection application. In many
applications the protection function shall not directly trip when there is a short circuit or ground
faults in the system. The time delay must be coordinated to the short circuit protections.
tResetn : Reset time for step n if definite time delay is used, given in s. The default value is 25 ms.
tnMin : Minimum operation time for inverse time characteristic for step n , given in s. When using
inverse time characteristic for the undervoltage function during very low voltages can give a short
operation time. This might lead to unselective trip. By setting
for other protections such unselective tripping can be avoided.
ResetTypeCrvn : This parameter for inverse time characteristic can be set to Instantaneous , Frozen
time , Linearly decreased . The default setting is Instantaneous .
tIResetn : Reset time for step n if inverse time delay is used, given in s. The default value is 25 ms.
TDn : Time multiplier for inverse time characteristic. This parameter is used for coordination
between different inverse time delayed undervoltage protections.
Application manual
×
VBase kV ( )
3
< ×
(%) VBase(kV)
ConnType . The function will operate if the voltage
VBase . When ConnType is set to PhN DFT or PhN RMS then
VBase by √3. VBase is used when ConnType is set to
2 out of 3 can be chosen. In
t1Min longer than the operation time
Voltage protection
(Equation 92)
(Equation 93)
n = 1 or 2). Therefore, the
1 out of 3 , 2 out of 3 or 3 out of
Section 8
203