ABB REB650 - Page 312

FA
A A 1L F 0P 0M
A
I
V I p Z R I Z
D
= × × + × + ×
EQUATION1600 V1 EN (Equation 63)
Where:
I
0P
is a zero sequence current of the parallel line,
Z
0M
is a mutual zero sequence impedance and
D
A
is the distribution factor of the parallel line, which is:
D
A
1 p–( ) Z
A
Z
AL
Z
B
+ +( ) Z
B
+×
2 Z
A
Z
L
2 Z
B
×+ +×
-----------------------------------------------------------------------------
=
EQUATION101 V1 EN
The K
N
compensation factor for the double line becomes:
K
N
Z
0L
Z
1L
–
3 Z
1L
×
------------------------
Z
0M
3 Z
1L
×
-----------------
I
0P
I
0A
-------
×+=
EQUATION102 V1 EN (Equation 64)
From these equations it can be seen, that, if Z
0m
= 0, then the general fault location
equation for a single line is obtained. Only the distribution factor differs in these two
cases.
Because the D
A
distribution factor according to equation
61 or 63 is a function of p, the
general equation 63 can be written in the form:
p
2
p K
1
K
2
K
3
R
F
×–+×– 0=
EQUATION103 V1 EN
(Equation 65)
Where:
A B
1
A L L ADD
V Z
K 1
I Z Z Z
= + +
× +
EQUATION1601 V1 EN (Equation 66)
A B
2
A L L ADD
V Z
K 1
I Z Z Z
= × +
× +
æ ö
ç ÷
è ø
EQUATION1602 V1 EN (Equation 67)
Section 12 1MRK 505 277-UUS C
Monitoring
306
Technical Manual