ABB Relion 670 Series Applications Manual page 221

1MRK 511 401-UEN Rev. K
OpModen : This parameter describes how many of the three measured voltages should be
below the set level to give operation for step n. The setting can be
of 3 . In most applications, it is sufficient that one phase voltage is low to give operation. If
UV2PTUV shall be insensitive for single phase-to-earth faults,
subtransmission and transmission networks the undervoltage function is mainly a system
supervision function and 3 out of 3 is selected.
Un< : Set operate undervoltage operation value for step n , given as % of the parameter UBase .
The setting is highly dependent on the protection application. It is essential to consider the
minimum voltage at non-faulted situations. Normally, this non-faulted voltage is larger than
90% of the nominal voltage.
tn : time delay of step n , given in s. This setting is dependent on the protection application. In
many applications the protection function shall not directly trip when there is a short circuit or
earth faults in the system. The time delay must be coordinated to the other 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 tripping. By setting
than the operation time 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.
kn : Time multiplier for inverse time characteristic. This parameter is used for coordination
between different inverse time delayed undervoltage protections.
ACrvn , BCrvn , CCrvn , DCrvn , PCrvn : Parameters to create a programmable under voltage
inverse time characteristic. Description of this can be found in the
CrvSatn : Tuning parameter that is used to compensate for the undesired discontinuity created
when the denominator in the equation for the customer programmable curve is equal to zero.
For more information, see the
IntBlkSeln : This parameter can be set to Off , Block of trip , Block all . In case of a low voltage the
undervoltage function can be blocked. This function can be used to prevent function when the
protected object is switched off. If the parameter is set
is prevented.
IntBlkStValn : Voltage level under which the blocking is activated set in % of UBase . This setting
must be lower than the setting
that is, about 10%.
tBlkUVn : Time delay to block the undervoltage step n when the voltage level is below
IntBlkStValn , given in s. It is important that this delay is shorter than the operate time delay of
the undervoltage protection step.
9.2 Two step overvoltage protection OV2PTOV
Bay control REC670
Application manual
Technical manual .
Un< . As switch of shall be detected the setting can be very low,
© Copyright 2017 Hitachi Power Grids. All rights reserved
1 out of 3 , 2 out of 3 or 3 out
2 out of 3 can be chosen. In
t1Min longer
Technical manual .
Block of trip or Block all unwanted trip
Section 9
Voltage protection
IP14545-1 v3
215