ABB Relion 670 Series Applications Manual page 224

Section 9
Voltage protection
and operation for phase-to-phase voltage over:
>
U (%) UBase(kV)
EQUATION1993 V1 EN-US
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
most applications it is sufficient that one phase voltage is high to give operation. If the
function shall be insensitive for single phase-to-earth faults
the voltage will normally rise in the non-faulted phases at single phase-to-earth faults. In
subtransmission and transmission networks the UV function is mainly a system supervision
function and 3 out of 3 is selected.
Un> : Set operate overvoltage operation value for step n , given as % of UBase . The setting is
highly dependent of the protection application. Here it is essential to consider the maximum
voltage at non-faulted situations. Normally this voltage is less than 110% of nominal voltage.
tn : time delay of step n , given in s. The setting is highly dependent of the protection
application. In many applications the protection function is used to prevent damages to the
protected object. The speed might be important for example in case of protection of
transformer that might be overexcited. The time delay must be co-ordinated with other
automated actions in the system.
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. For very
high voltages the overvoltage function, using inverse time characteristic, can give very short
operation time. This might lead to unselective trip. By setting
time for other protections such unselective tripping can be avoided.
ResetTypeCrvn : This parameter for inverse time characteristic can be set: 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 co-ordination
between different inverse time delayed undervoltage protections.
ACrvn , BCrvn , CCrvn , DCrvn , PCrvn : Parameters to set to create programmable under voltage
inverse time characteristic. Description of this can be found in the technical reference manual.
CrvSatn : When the denominator in the expression of the programmable curve is equal to zero
the time delay will be infinity. There will be an undesired discontinuity. Therefore a tuning
parameter
Un> · (1.0 + CrvSatn /100) the used voltage will be: Un> · (1.0 + CrvSatn /100). If the
to
programmable curve is used, this parameter must be calculated so that:
CrvSatn
×
B
100
EQUATION1448 V1 EN-US
218
×
CrvSatn is set to compensate for this phenomenon. In the voltage interval Un> up
- >
C 0
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1MRK 511 401-UEN Rev. K
1 out of 3 , 2 out of 3 , 3 out of 3 . In
1 out of 3 can be chosen, because
t1Min longer than the operation
Bay control REC670
Application manual
(Equation 97)
(Equation 98)