ABB RELION 670 SERIES Applications Manual page 448

Section 8
Impedance protection
442
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
inner boundary of the oscillation detection characteristic. The minimum required value is
calculated according to the procedure listed in equation 413, 414,
=
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 417.
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
tP2 = 10 ms
Consider RLdInFw = 75.0Ω.
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
è ø
75.8
= =
max1 0.61
123.5
° - °
91.5 64.5
=
10.7 ms
× °
7 360
1MRK 506 369-UUS -
, it is necessary to reduce the
Out
415 and 416.
+ ° = °
91.5
= W
75.8
ö
÷
ø
Line distance protection REL670 2.2 ANSI
Application manual
(Equation 413)
(Equation 414)
(Equation 415)
(Equation 416)
(Equation 417)