Toshiba GRL150-100 Series Instruction Manual page 141

6.5.2 Protection Scheme
Protection schemes implemented in GRL150 are basically for unit protection. It is recommended
that the protection schemes are tested under end-to-end mode. The setup of the end-to-end
synchronized test is described in Section 6.5.1.
In the protection scheme tests, a dynamic test set is required to simulate power system pre-fault,
fault and post-fault conditions.
The "Sim.fault" on the LCD "Test" menu is available to test local and remote terminals
synchronously. For use, see Section 4.2.7.4.
Tripping is observed with the tripping command output relays after a simulated fault occurs.
Differential tripping
When a phase current is applied, instantaneous per phase based tripping or three-phase tripping is
performed depending on the fault types.
The tripping should be checked for the current which is two times or larger than the minimum
operating current DIFI1. Operating time is measured by the operating time of the tripping
command output relay. It will typically be 1 cycle.
Check that the indications and recordings are correct.
Check that the indications and recordings are correct.
Circuit Breaker failure tripping
• Set the scheme switch [BTC] to "ON" and [RTC] to "DIR" or "OC".
• Apply a fault, retain it and input an external trip signal. Check that the retrip output relays
operate after the time setting of the TRTC and the adjacent breaker tripping output relay
operates after the time setting of the TBTC.
6.5.3 Metering and Recording
The metering function can be checked while testing the AC input circuit. See Section 6.4.4.
Fault recording can be checked while testing the protection schemes. Open the "Fault record"
screen and check that the descriptions are correct for the fault concerned.
Recording events are listed in Appendix G. There are internal events and external events by binary
input commands. Event recording on the external event can be checked by changing the status of
binary input command signals. Change the status in the same way as the binary input circuit test
(see Section 6.4.2) and check that the description displayed on the "Event record" screen is
correct. Some of the internal events can be checked in the protection scheme tests.
Disturbance recording can be checked while testing the protection schemes. The LCD display
only shows the date and time when a disturbance is recorded. Open the "Disturbance record"
screen and check that the descriptions are correct.
Details can be displayed on the PC. Check that the descriptions on the PC are correct. For details
on how to obtain disturbance records on the PC, see the RSM100 Manual.
⎯ ⎯
140
6 F 2 S 0 8 2 8