ABB REL650 Applications Manual page 170

Section 6
Impedance protection
164
d d
-
76.5
= =
tP 1 In Out
× °
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
inner boundary of the oscillation detection characteristic. The minimum required value is
calculated according to the procedure listed in equation 86, 87,
=
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 90.
d d
-
= =
tP 2 In Out
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
1MRK 506 334-UUS A
, it is necessary to reduce the
Out
88 and 89.
+ ° = °
91.5
= W
75.8
ö
÷
ø
Application manual
(Equation 85)
(Equation 86)
(Equation 87)
(Equation 88)
(Equation 89)
(Equation 90)