Table of Contents
Advertisement
Section 8
Voltage protection
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
HystAbsn : Absolute hysteresis set in % of UBase . The setting of this parameter is highly
dependent of the application. If the function is used as control for automatic switching of
reactive compensation devices the hysteresis must be set smaller than the voltage change
after switching of the compensation device.
8.3
Two step residual overvoltage protection ROV2PTOV
8.3.1
Identification
Function description
Two step residual overvoltage
protection
212
CrvSatn is set to compensate for this phenomenon. In the voltage interval Un> up
-
>
C
0
IEC 61850
IEC 60617
identification
identification
ROV2PTOV
2(U0>)
IEC15000108 V1 EN-US
1MRK 505 370-UEN D
t1Min longer than the operation
(Equation 73)
ANSI/IEEE C37.2
device number
59N
Busbar protection REB670
Application manual
IP14546-1 v4
SEMOD54295-2 v6
Advertisement
Table of Contents
