Inverse Definite Minimum Time Characteristcs - ABB REU 610 Technical Reference Manual

1MRS755972
5.1.4.6.
Voltage Relay
Technical Reference Manual - ANSI Version
The CBFAIL unit generates a trip signal via output PO2 when the set operate
time of CBFAIL expires.
The CBFAIL can be triggered internally via protection functions. All the
signals, except external trip, routed to output PO1 trigger the CBFAIL. If the
fault situation is not cleared when the set operate time has elapsed, the
CBFAIL generates a trip signal via output PO2.
The CBFAIL can also be selected to be triggered externally by applying a
digital input signal to the relay, if the maximum of all three phase-to-phase
voltages is above 0.15× U
set operate time has elapsed, the CBFAIL generates a trip signal via output
PO2.
Internal triggering is selected by activating the CBFAIL in SGF1/6 and
external triggering by activating the CBFAIL in SGB1...5/7.
Normally, the CBFAIL controls the upstream circuit breaker. However, it can
also be used for tripping via redundant trip circuits of the same circuit
breaker.

Inverse definite minimum time characteristcs

Each of the overvoltage and undervoltage elements can be given either a
definite-time or an inverse definite minimum time (IDMT) characteristic. The
following setting parameters determine the operation mode of the overvoltage
and undervoltage protection elements:
Table 5.1.4.6.-1 Operation mode setting parameters
Protection Parameter
element
59P-1 S3
59P-2/47 S11
27P-1 S15
27P-2/27D S22
At IDMT characteristic, the operate time of the element is dependent on the
voltage value: the greater the deviation from the setting value, the shorter the
operate time. Three time/voltage curve groups are available: A, B and C.
An overvoltage element picks up when the measured voltage exceeds the
setting value of the element. An undervoltage element picks up when the
measured voltage drops below the setting value of the element. However, the
(VT). If the fault situation is not cleared when the
n
Setting
0 = definite time
1 = curve A
2 = curve B
0 = definite time
1 = curve A
2 = curve B
0 = definite time
1 = curve C
0 = definite time
1 = curve C
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