The Non-Compensated Impedance Model; Iec 60870-5-103 - ABB RED650 Technical Manual

Section 15
Monitoring
15.9.7.3
15.9.7.4
598
2
× ( ) ( ) R
p – p Re K + Re K
1 2
EQUATION107 V1 EN-US
× × ( ) × ( ) R
– p Im K + Im K –
1 2
EQUATION108 V1 EN-US
If the imaginary part of K
and then inserted to equation 90. According to equation 90, the relative distance to
the fault is solved as the root of a quadratic equation.
Equation 90 gives two different values for the relative distance to the fault as a
solution. A simplified load compensated algorithm, which gives an unequivocal
figure for the relative distance to the fault, is used to establish the value that should
be selected.
If the load compensated algorithms according to the above do not give a reliable
solution, a less accurate, non-compensated impedance model is used to calculate
the relative distance to the fault.

The non-compensated impedance model

In the non-compensated impedance model, I
fault current:
× × ×
U = p Z I + R I
A 1 L A F A
EQUATION109 V1 EN-US
Where:
I is according to table 417.
A
The accuracy of the distance-to-fault calculation, using the non-compensated
impedance model, is influenced by the pre-fault load current. So, this method is
only used if the load compensated models do not function.

IEC 60870-5-103

The communication protocol IEC 60870-5-103 may be used to poll fault location
information from the IED to a master (that is station HSI). There are two outputs
that must be connected to appropriate inputs on the function block I103StatFltDis,
FLTDISTX gives distance to fault (reactance, according the standard) and
CALCMADE gives a pulse (100 ms) when a result is obtainable on FLTDISTX
output.
× ( )
– Re K = 0
F 3
× × ( )
Im K = 0
F 3
is not zero, R can be solved according to equation 91,
3 F
line current is used instead of I
A
1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
(Equation 90)
(Equation 91)
M14983-121 v3
FA
(Equation 92)
M14983-135 v2