Fault Locator; Fault Locator Settings Example; Opto-Input Time Stamping - GE MiCOM P40 Agile Technical Manual

P14x
4.3

FAULT LOCATOR

Some models provide fault location functionality. It is possible to identify the fault location by measuring the fault
voltage and current magnitude and phases and presenting this information to a Fault Locator function. The fault
locator is triggered whenever a fault record is generated, and the subsequent fault location data is included as
part of the fault record. This information is also displayed in the Fault Location cell in the VIEW RECORDS column.
This cell will display the fault location in metres, miles ohms or percentage, depending on the chosen units in the
Fault Location cell of the MEASURE'T SETUP column.
The Fault Locator uses pre-fault and post-fault analogue input signals to calculate the fault location. The result is
included it in the fault record. The pre-fault and post-fault voltages are also presented in the fault record.
4.3.1

FAULT LOCATOR SETTINGS EXAMPLE

Assuming the following data for the protected line:
Parameter
CT Ratio
VT Ratio
Line Length
Positive sequence line impedance ZL1 (per km|)
Zero sequence line impedance ZL0
Zero sequence mutual impedance ZM0
The line impedance magnitude and angle settings are calculated as follows:
Ratio of secondary to primary impedance = CT ratio/VT ratio = 0.12
●
Positive sequence line impedance ZL1 (total) = 0.12 x 10(0.484Ð79.4°) = 0.58 Ð79.4°
●
Therefore set line length = 0.58
●
Line angle = 79°
●
The residual impedance compensation magnitude and angle are calculated using the following formula:
(
−
0 1
ZL ZL
= =
KZn
3 1
ZL
Therefore the settings are:
KZN Residual = 0.41
●
KZN Res Angle = -14
●
4.4

OPTO-INPUT TIME STAMPING

Each opto-input sample is time stamped within a tolerance of +/- 1 ms with respect to the Real Time Clock. These
time stamps are used for the opto event logs and for the disturbance recording. The device needs to be
synchronised accurately to an external clock source such as an IRIG-B signal or a master clock signal provided in
the relevant data protocol.
For both the filtered and unfiltered opto-inputs, the time stamp of an opto-input change event is the sampling time
at which the change of state occurred. If multiple opto-inputs change state at the same sampling interval, these
state changes are reported as a single event.
P14xEd1-TM-EN-1
) (
+ −
0 34 1 03 0 089
. j . .
(
∠
3 0 484 79 4
. .
1200/5
230000/115
10 km
0.089+j0.476 Ohms/km
0.34+j1.03 ohms/km
0.1068+j0.5712 Ohms/km
)
+
∠
0 476
j .
0 0 6 65 2
. .
=
)
° ∠
1 45 79 4
.
Chapter 14 - Monitoring and Control
Value
°
= ∠ − °
0 41 . 14 2 .
°
.
319