ABB REL670 2.2 IEC, Руководство по применению

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( )
1
10.71 75.6
L
Z j
= + W
EQUATION1328 V1 EN-US
Positive sequence line impedance
( )
1
1.15 43.5
SA
Z j
= + W
EQUATION1329 V1 EN-US
Positive sequence source impedance behind A bus
( )
1
5.3 35.7
SB
Z j
= + W
EQUATION1330 V1 EN-US
Positive sequence source impedance behind B bus
max
1000 S MVA
=
EQUATION1331 V1 EN-US
Maximum expected load in direction from A to B (with minimum
system operating voltage U
min
)
( )
max
cos 0.95
j
=
EQUATION1332 V1 EN-US
Power factor at maximum line loading
max
25
j
= °
EQUATION1333 V1 EN-US
Maximum expected load angle
2.5
si
f Hz
=
EQUATION1334 V1 EN-US
Maximum possible initial frequency of power oscillation
7.0
sc
f Hz
=
EQUATION1335 V1 EN-US
Maximum possible consecutive frequency of power oscillation
The minimum load impedance at minimum expected system voltage is equal to
equation
402 .
2 2
min
min
max
380
144.4
1000
L
U
Z
S
= = = W
EQUATION1337 V1 EN-US
(Equation 402)
The minimum load resistance R
Lmin
at maximum load and minimum system
voltage is equal to equation 403 .
( )
min min max
cos 144.4 0.95 137.2
L L
R Z
j
= × = × = W
EQUATION1338 V1 EN-US
(Equation 403)
The system impedance Z
S
is determined as a sum of all impedances in an
equivalent two-machine system, see figure 224 . Its value is calculated according to
equation 404 .
( )
1 1 1
17.16 154.8
S SA L SB
Z Z Z Z j
= + + = + W
EQUATION1339 V1 EN-US
(Equation 404)
The calculated value of the system impedance is of informative nature and helps in
determining the position of the oscillation center, see figure
225 , which is for a
general case calculated according to equation 405 .
Section 8
1MRK 506 369-UEN B
Impedance protection
410 Line distance protection REL670 2.2 IEC
Application manual