ABB Relion RES670, Техническое руководство

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The second method
This method is more exact. If the break-time of the circuit breaker is known, (and
specified as the setting
tBreaker ) than it is possible to initiate a trip (break) command
almost exactly tBreaker milliseconds before the rotor (power) angle reaches 0 degrees,
where the currents are at their minimum possible values. The breaker contacts open at
almost exactly 0 degrees, as illustrated in Figure
48 for tBreaker = 0.060 s. The point
in time when the breaker opening process must be initiated is estimated by solving on-
line the so called “synchronizer” differential equation. Note that if
tBreaker is left on
the initial (default) value, which is zero (0), then the alternative setting TripAngle
decides when the trip command is given. If specified tBreaker > 0, for example
tBreaker = 0.040 second, then automatically, the TripAngle is ignored and the second,
more exact method applied.
-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8
-0.4
-0.2
0
0.2
0.4
0.6
Real part (R) of Z in Ohms →
Im
ag
ina
ry
pa
rt
(X
) o
f Z
in
O
hm
s
→
R[Ohm]
no trip
region
loci of Z(R, X)
no trip
region
rotor angle
= ±180°
X[Ohm]
RE - Receiving End (infinite bus)
←
this circle
is loci of
the rotor
angle = 90°
2
relay
SE - Sending End (generator)
no trip
region
inside
circle
outside the
circle is the trip
region for
TripAngle <= 90°
3
here rotor
angle
is -90°
here
rotor angle
is +90°
1
trip
region
←
Z - line connects
points SE & RE
IEC10000114-1-en.vsd
IEC10000114 V1 EN-US
Figure 47: The imaginary offset Mho circle represents loci of the impedance Z(R,
X) for which the rotor angle is 90 degrees
Section 7
1MRK 511 408-UUS A
Impedance protection
166 Phasor measurement unit RES670 2.2 ANSI
Technical manual