Functions
2.21 Fault Locator
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
391
Figure 2-182
Fault currents and voltages on double–end fed lines
M
: Measuring point
E1, E2
: Source voltage (EMF)
IF1, IF2
: Partial fault currents
IF1 + IF2
: Total fault current
UF1
: Fault voltage at the measuring point
RF
: Common fault resistance
ZF1, ZF2
: Fault impedances
ZF1E, ZF2E
: Earth fault impedances
ZS1, ZS2
: Source impedances
ZS1E, ZS2E
: Earth source impedances
2.21.2
Setting Notes
General
The fault location function is only in service if it was set to
Enabled
during the configuration of the device func-
tions (Section 2.1.1.3, address
138
).
In address
160
L-sections FL
you can set the number of line sections. If you set the number to
2
Sections
or
3 Sections
, a number of additional tabs for setup will appear in DIGSI. The default setting here
is
1 Section
which means that the line parameters (addresses
1116
,
1117
,
1120
and
1121
are relevant
(see also Section 2.1.4).
If the fault location calculation is to be started by the trip command of the protection, set address
3802
START
=
TRIP
. In this case a fault location is only output if the device has also issued a trip. The fault location calcu-
lation can, however, also be started with each fault detection of the device (address
3802
START
=
Pickup
).
In this case the fault location is also calculated if, for example, a different protection device cleared the fault. If
the fault is located outside the protected line, only the single-ended method is used for fault location.
To calculate the distance to fault in kilometers or miles, the device needs the reactance per unit length in
Ω
/km
or
Ω
/mile, and in the case of double-ended fault location the capacitance per unit length in
μ
F/km or
μ
F/mile.
For correct indication of the fault location in % of line length, the correct line length has also to be entered. For
the double-ended fault locator this information is mandatory. These setting parameters were already applied
with the Power System Data 2 (Section 2.1.4.1 at „General Line Data“).
A prerequisite for the correct indication of the fault location is furthermore that the other parameters that influ-
ence the calculation of the distance to fault have also been set correctly.
If only one line section (address
160
= ) is set, these parameters are:
•
1116
RE/RL(Z1)
,
•
1117
XE/XL(Z1)
or
•
1120
K0 (Z1)
,
•
1121
Angle K0(Z1)
.