Fault Locator - Toshiba GRL100-701B Instruction Manual

2.17 Fault Locator

2.17.1 Application
GRL100 provides the following two type fault locators.
- Fault location using the local and remote end data (when current differential protection is
applied.) (∗)
- Fault location using the only local end data (when current differential protection is not
applied.)
Note (∗): The fault location using the local and remote end data is applied. In case of
communication failure, however, the fault location using the only local end data is
applied.
The measurement result is expressed as a percentage (%) of the line length and the distance (km)
and is displayed on the LCD on the relay front panel. In three-terminal application, however, the
measurement result is expressed as a fault section instead of a percentage. It is also output to a
local PC or RSM (relay setting and monitoring) system.
To measure the distance to fault, the fault locator requires minimum 3 cycles as a fault duration
time.
In distance to fault calculations, the change in the current before and after the fault has occurred is
used as a reference current, alleviating influences of the load current and arc voltage. As a result,
the location error in fault location using only local end data is a maximum of ±2.5 km for faults at
a distance of up to 100 km, and a maximum of ±2.5% for faults at a distance between 100 km and
399.9 km. The location error in fault location using local and remote ends data is a maximum of
±2.0 km for faults at a distance of up to 100 km, and a maximum of ±2.0% for faults at a distance
between 100 km and 399.9 km at the positive differential current more than In (rated current). If a
fault current is more than 25×In, the location error is larger than above. (See Appendix K.)
Fault location is enabled or disabled by setting "Fault locator" to "ON" or "OFF" on the "Fault
record" screen in the "Record" sub-menu.
2.17.2 Starting Calculation
Calculation of the fault location can be initiated by one of the following tripping signals.
• current differential protection trip
• carrier protection (command protection) trip
• zone 1 trip
• zone 2 trip
• zone 3 trip
• external protection trip
2.17.3 Displaying Location
The measurement result is stored in the "Fault record" and displayed on the LCD of the relay front
panel or on the local or remote PC. For displaying on the LCD, see Section 4.2.3.1.
In the two-terminal line, the location is displayed as a distance (km) and a percentage (%) of the
line length.
In the three-terminal line, the location is displayed as a distance (km). To discriminate faults in the
second and the third section, the fault section is supplemented.
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6 F 2 S 0 8 5 0