Manual MRG3
SEG Electronics GmbH
DOK-TD-MRG3, Rev. D
61
6. Maintenance and Commissioning
The test instructions following below help to verify the protection relay performance before or dur-
ing commissioning of the protection system. To avoid a relay damage and to ensure a correct relay
operation, make sure that:
the auxiliary power supply rating corresponds to the auxiliary voltage on site.
the rated current and rated voltage of the relay correspond to the plant data on site.
the current transformer circuits and voltage transformer circuits are connected to the relay
and
that all signal circuits and output relays are connected correctly.
6.1 Connection of aux. voltage
Note!
Prior to switch on the auxiliary power supply, be sure that the auxiliary supply voltage corresponds
with the rated data on the type plate.
Switch on the auxiliary power supply to the relay and check that the message "WW" appears on
the display and the self supervision alarm relay (watchdog) is energized (contact at terminals D7
and E7 closed).
It may happen that the relay is tripped because of under- voltage condition after power-on. In this
case, “TRIP” is shown on the display and LEDs L1; L2; L3 will flash in order to indicate the trip
phase as well as the LEDs for the cause of trip, namely LEDs U< + 1 + 2 + < for U< and/or U<<.
There are different possibilities to de-activate the two steps:
Press the push button <ENTER>, thus entering into the setting mode. Now set the
parameters U< and U<< to "EXIT" to block the under voltage functions. After that, press the
<SELECT/RESET> for app. 3 s to reset the LEDs and "TRIP" message.
The under voltage tripping after power on can also be eliminated by applying three phase
rated voltages after power-on and reset the LED and "TRIP" message.
Apply auxiliary voltage to the external blocking input (Terminals E8/D8) to inhibit the under
voltage functions(refer to chapter 5.9.1). and press the <SELECT/RESET> for app. 3 s to
reset the LEDs and "TRIP" message.
6.2 Testing of the output relays and LEDs
Prior to commencing this test, interrupt the trip circuit to the circuit breaker if tripping is not desired.
By pressing the push button <TRIP> once, the display shows the first part of the software version
of the relay (e.g. „D08-“). By pressing the push button <TRIP> twice, the display shows the second
part of the software version of the relay (e.g. „4.01“. The software version should be quoted in all
correspondence. Pressing the <TRIP> button once more, the display shows "PSW?". Please enter
the correct password to proceed with the test. The message "TRI?" will follow. Confirm this mes-
sage by pressing the push button <TRIP> again. All output relays should then be activated and the
self supervision alarm relay (watchdog) be de energized one after another with a time interval of 1
second. Thereafter, reset all output relays back to their normal positions by pressing the push but-
ton <SELECT/RESET>.