76.5 64.5
1 13.3
360 2.5 360
In Out
si
tP ms
f
d d
-
° - °
= = =
× ° × °
EQUATION1347 V1 EN (Equation 85)
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
Out
, it is necessary to reduce the
inner boundary of the oscillation detection characteristic. The minimum required value is
calculated according to the procedure listed in equation
86, 87, 88 and 89.
EQUATION1348 V1 EN (Equation 86)
min min
360 1 360 2.5 0.030 64.5 91.5
In si Out
f tP
d d
-
= °× × + = °× × + ° = °
EQUATION1349 V1 EN (Equation 87)
max1
min
155.75
75.8
91.5
2 tan
2 tan
2
2
d
-
= = = W
æ ö æ ö
×
×
ç ÷
ç ÷
è ø
è ø
S
in
Z
RLdInFw
EQUATION1350 V1 EN (Equation 88)
max1
75.8
0.61
123.5
= = =
RLdInFw
kLdRFw
RLdOutFw
EQUATION1351 V1 EN (Equation 89)
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.
max
91.5 64.5
2 10.7
360 7 360
In Out
sc
tP ms
f
d d
-
° - °
= = =
× ° × °
EQUATION1352 V1 EN
(Equation 90)
The final proposed settings are as follows:
RLdOutFw = 123.5Ω
kLdRFw = 0.61
tP1 = 30 ms
Section 6 1MRK 506 334-UUS A
Impedance protection
164
Application manual
To Next Page
Loading...
