Signal
Description
BlockInp
Input for blocking the function.
•
F: not blocked
•
T: blocked
•
xx: all binary inputs (or outputs of protection functions)
Trip
Tripping signal
Start
Pick-up signal
5.6.6
Configuration
GUID-3BEB8035-50E3-42E4-A31B-F0BF4F40B9CB v1
The following parameters have to be set:
Setting
V-setting
Delay
Delay
Over or undervoltage
MaxMin
Number of phases
NrOfPhases
Two of these functions are frequently applied in a two-stage scheme. The first stage detects
lower prolonged overvoltages while the second guards against higher overvoltages, which
have to be cleared quickly.
Pick-up voltage (V-setting)
Single-phase VT: A setting of 1.3 U
N
corresponds to a pick-up voltage of 130 V at the input of
the VT.
Y-connected three-phase VTs: A setting of 1.3 U
N
corresponds to a pick-up voltage of 130V / √3
at the input of the VT(phase-to-neutral voltage).
Compensating any difference between the rated voltages of VTs U
N1
and protected unit U
GN
is
recommended. This is achieved with the aid of the reference value of the A/D channel or by
correcting the voltage setting.
For example, for U
GN
= 12 kV and U
N1
= 15 kV, the setting for a pick-up voltage of 1.4 U
GN
should
be:
1
12
1.4
1.4
1.12
15
GN
N
U
kV
U
kV
MaxMin
This parameter provides a choice of the following settings:
•
MIN (3ph): Protection picks up when all three-phase voltages have fallen below setting.
•
MIN (1ph): Protection picks up when the lowest of the phase voltages falls below setting.
•
MAX (3ph): Protection picks up when all three-phase voltages have exceeded setting.
•
MAX (1ph): Protection picks up when the highest of the phase voltages exceeds setting.
Operating characteristic of a two-stage overvoltage protection
(U
N
= rated relay voltage)
1MRK 505 406-UEN B
Section 5
Bay protection functions
Bay protection functions REB500
113
Technical manual
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