Technical Data - ABB RELION 670 Series Technical Manual

1MRK 502 066-UUS B
sensitivity Idmin. Any search for an external fault is aborted if trip request counter is greater
than zero.
6. As long as the external fault persists, an additional temporary trip condition is introduced.
This means that REFPDIF (87N) is temporarily desensitized.
7. If point P(Ibias, Idiff) is found to be above the operate-bias characteristic), so that trip
request counter is greater than zero, a directional check can be made. The directional check is
made only if Iresidual (3Io) is more than 3% of the
means "external fault", then the internal trip request is reset. If the directional check cannot
be executed, then direction is no longer a condition for a trip.
8. When neutral current, residual current and bias current are within some windows and some
timing criteria are fulfilled, the ratio of 2
to be above 40%, the trip request counter is reset and TRIP remains zero.
9. Finally, a check is made if the trip request counter is equal to, or higher than 2. If yes, and at
the same instance of time t
least 50% of the highest bias current Ibiasmax (Ibiasmax is the highest recording of any of the
three phase currents measured during the disturbance), then REFPDIF (87N) sets output TRIP
to 1. If the counter is less than 2, the TRIP signal remains zero.
6.4.8

Technical data

Table 78:
Function
Trip characteristic
Reset ratio
Minimum pickup, IdMin
Directional characteristic
Trip time, trip at 0 to 10 x
IdMin
Reset time, trip at 10 to 0 x
IdMin
Second harmonic blocking
Technical manual
REFtrip
REFPDIF (87N) technical data
Range or value
Adaptable
>95%
(4.0-100.0)% of IBase
Fixed 180 degrees or ±60 to
±90 degrees
Min. = 15 ms
Max. = 30 ms
Min. = 15 ms
Max. = 30 ms
40.0% of fundamental
IBase current. If the result of the check
nd
to fundamental harmonic is calculated. If it is found
, the actual bias current at this instance of time t
Accuracy
±1.0% of I
±1.0% of I at I > I
-
±1.0% of I
±2.0 degrees
-
-
±1.0% of I
Differential protection
REFtrip
at I ≤ I
n n
n
n
n
Section 6
is at
IP12661-1 v1
M13062-1 v16.1.1
175