ABB RET670 Applications Manual page 369

1MRK504116-UUS C
Application manual
d d
-
76.5
= =
In Out
tP 1
× °
f 360 2.5 360
si
EQUATION1347 V1 EN
The general tendency should be to set the tP1 time to at least 30 ms, if possible. Since
it is not possible to further increase the external load angle δ
reduce the inner boundary of the oscillation detection characteristic. The minimum
required value is calculated according to the procedure listed in equation 304, 305,
and 307.
=
tP 1 30 ms
min
EQUATION1348 V1 EN
d
= ° × ×
360 f tP 1
-
In min si
EQUATION1349 V1 EN
=
RLdInFw
max1
×
2 tan
EQUATION1350 V1 EN
RLdInFw
=
kLdRFw
RLdOutFw
EQUATION1351 V1 EN
Also check if this minimum setting satisfies the required speed for detection of
consecutive oscillations. This requirement will be satisfied if the proposed setting of
tP2 time remains higher than 10 ms, see equation 308.
d d
-
= =
In Out
tP 2
max
× °
f 360
sc
EQUATION1352 V1 EN
The final proposed settings are as follows:
RLdOutFw = 123.5Ω
kLdRFw = 0.61
tP1 = 30 ms
° - °
64.5
=
13.3 ms
× °
d
+ = ° × ×
360 2.5 0.030 64.5
min Out
Z
155.75
S
=
d
æ ö æ
91.5
×
-
in min 2 tan
ç ÷ ç
2
è 2 ø è
75.8
= =
max1 0.61
123.5
° - °
91.5 64.5
=
10.7 ms
× °
7 360
Section 3
IED application
, it is necessary to
Out
+ ° = °
91.5
= W
75.8
ö
÷
ø
(Equation 303)
306
(Equation 304)
(Equation 305)
(Equation 306)
(Equation 307)
(Equation 308)
363