ABB Relion 670 Series Applications Manual page 115

1MRK 511 407-UUS Rev. J
RLdOutFw
EQUATION1343 V1 EN-US
It is a general recommendation to set the inner boundary
characteristic to 80% or less of its outer boundary. Take special care during the settings of timers
tP1 and tP2 which is included in the oscillation detection logic. This requires the maximum
permitted setting values of factor
maximum possible value of
RLdInFw
EQUATION1344 V3 EN-US
The load angles, which correspond to external δ
oscillation detection characteristic in forward direction, are calculated with sufficient accuracy
according to equation
d
= ×
2 arc tan
Out
EQUATION1345 V1 EN-US
d
= ×
2 arc tan
In
EQUATION1346 V1 EN-US
The required setting
difference according to equation 26.
d
=
tP 1
EQUATION1347 V1 EN-US
The general tendency should be to set the
possible to further increase the external load angle δ
boundary of the oscillation detection characteristic. The minimum required value is calculated
according to the procedure listed in equation 27, 28,
tP 1
min
EQUATION1348 V1 EN-US
d
-
In min
EQUATION1349 V1 EN-US
Phasor measurement unit RES670
Application manual
= × =
K R 0.9 137.2 123.5
L L min
RLdInFw .
= ×
kLdRFw RLdOutFw
24 and 25
æ
Z
S
ç
ç
×
2 RLdOutFw
è
æ
Z
S
ç
ç
×
2 RLdInFw
è
max
tP1 of the initial oscillation detection timer depends on the load angle
d
- ° -
76.5 64.5
=
In Out
× ° ×
f 360 2.5 360
si
=
30 ms
d
= ° × × +
360 f tP 1
si min Out
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× = W
kLdRFw = 0.8. Equation
= W
98.8
and internal δ
Out
respectively.
ö
æ 155.75 ö
÷ = ×
2 arc tan
ç ÷
÷
×
è 2 123.5 ø
ø
ö
æ ö
155.75
÷ = × =
2 arc tan
ç ÷
÷
×
è 2 98.8 ø
ø
°
=
13.3 ms
°
tP1 time to at least 30 ms, if possible. Since it is not
, it is necessary to reduce the inner
Out
29 and 30.
= ° × × +
360 2.5 0.030 64.5
RLdInFw of the oscillation detection
23 presents the corresponding
boundary of proposed
In
= °
64.5
°
76.5
° = °
91.5
Section 7
Impedance protection
(Equation 22)
(Equation 23)
(Equation 24)
(Equation 25)
(Equation 26)
(Equation 27)
(Equation 28)
109