ABB Relion 670 Series Technical Reference Manual page 949

1MRK505222-UUS C
Technical reference manual
Z Z
–
0L 1L
----------------------- -
K =
N ×
3 Z
1L
EQUATION99 V1 EN
DI is the change in current, that is the current after the fault minus the current before
the fault.
In the following, the positive sequence impedance for Z
the equations, because this is the value used in the algorithm.
For double lines, the fault equation is:
I
= × × + ×
V I p Z FA
A A 1L
D
A
EQUATION1600 V1 EN
Where:
I is a zero sequence current of the parallel line,
0P
Z is a mutual zero sequence impedance and
0M
D is the distribution factor of the parallel line, which is:
A
( ) × (
1 p – Z
---------------------------------------------------------------------------- -
D =
A
×
2 Z
A
EQUATION101 V1 EN
The K compensation factor for the double line becomes:
N
Z – Z Z
0L 1L 0M
×
----------------------- - ---------------- -
K = +
N × ×
3 Z 3 Z
1L 1L
EQUATION102 V1 EN
From these equations it can be seen, that, if Z
equation for a single line is obtained. Only the distribution factor differs in these two
cases.
Because the D distribution factor according to equation
A
the general equation 186
2
× ×
p – p K + K – K R =
1 2 3 F
EQUATION103 V1 EN
+ ×
R I Z
F 0P 0M
)
+ Z + Z + Z
A A L B B
×
+ Z + 2 Z
L B
I
0P
-------
I
0A
= 0, then the general fault location
0m
can be written in the form:
0
Section 15
Monitoring
(Equation 185)
, Z and Z is inserted into
A B L
(Equation 186)
(Equation 187)
184 or 186 is a function of p,
(Equation 188)
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