Multiply the required resistance for the same safety factor K
L
with the ratio
between actual voltage and 400kV when the rated voltage of the line under
consideration is higher than 400kV. The outer boundary
RLdOutFw
obtains in this
particular case its value according to equation
.
min
0.9 137.2 123.5
L
L
RLdOutFw K
R
=
×
=
×
=
W
EQUATION1343 V1 EN-US
(Equation 19)
It is a general recommendation to set the inner boundary
RLdInFw
of the
oscillation detection 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
kLdRFw
presents the corresponding maximum possible
value of
RLdInFw
.
98.8
=
×
=
W
RLdInFw
kLdRFw RLdOutFw
EQUATION1344 V3 EN-US
(Equation 20)
The load angles, which correspond to external δ
Out
and internal δ
In
boundary of
proposed oscillation detection characteristic in forward direction, are calculated
with sufficient accuracy according to equation
155.75
2 arc tan
2 arc tan
64.5
2
2 123.5
d
æ
ö
æ
ö
ç
÷
= ×
= ×
=
°
ç
÷
ç
÷
×
×
è
ø
è
ø
S
Out
Z
RLdOutFw
EQUATION1345 V1 EN-US
(Equation 21)
max
155.75
2 arc tan
2 arc tan
76.5
2
2 98.8
d
æ
ö
æ
ö
ç
÷
= ×
= ×
=
°
ç
÷
ç
÷
×
×
è
ø
è
ø
S
In
Z
RLdInFw
EQUATION1346 V1 EN-US
(Equation 22)
The required setting
tP1
of the initial oscillation detection timer depends on the
load angle difference according to equation
.
76.5
64.5
1
13.3
360
2.5 360
In
Out
si
tP
ms
f
d
d
-
° -
°
=
=
=
×
°
×
°
EQUATION1347 V1 EN-US
(Equation 23)
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
1MRK 511 407-UEN C
Section 7
Impedance protection
Phasor measurement unit RES670 2.2 IEC
113
Application manual
Summary of Contents for Relion RES670
Page 1: ...RELION 670 SERIES Phasor measurement unit RES670 Version 2 2 IEC Application manual...
Page 2: ......
Page 46: ...40...
Page 52: ...46...
Page 92: ...86...
Page 112: ...106...
Page 178: ...172...
Page 216: ...210...
Page 232: ...226...
Page 286: ...280...
Page 328: ...322...
Page 340: ...334...
Page 380: ...374...
Page 381: ...375...