34
TD_MRN3-3_08.06_GB
6
Relay testing and
commissioning
The following test instructions should help to verify the
protection relay performance before or during commis-
sioning of the protection system. To avoid a relay
damage and to ensure a correct relay operation, be
sure that:
•
The auxiliary power supply rating corresponds to the
auxiliary voltage on site.
•
The rated frequency and rated voltage of the relay
correspond to the plant data on site.
•
The voltage transformer circuits are connected to the
relay correctly.
•
All signal circuits and output relay circuits are con-
nected correctly.
6.1 Power-On
NOTE!
Prior to switch on the auxiliary power supply, be sure
that the auxiliary supply voltage corresponds to the
rated data on the type plate.
Switch on the auxiliary power supply to the relay and
check that the message "ISEG" appears on the display
and the self supervision alarm relay (watchdog) is en-
ergized (Contact terminals D7 and E7 closed).
It may happen that the relay is tripped because of un-
der- voltage condition after power-on. (The message
"TRIP" on the display and LED L1, L2, L3 and U1 light
up red). In case that undervoltage condition has been
detected after power-on, because no input voltages
were applied to the relay. In this case:
•
press the push button <ENTER>, thus entering into
the setting mode. Now set the parameters for the
under voltage characteristics Char1+U<1;
Char2+U<1 and the pick-up value of the first volt-
age level U1 to "EXIT" to block the undervoltage
functions. After that, press the <SELECT/RESET> for
app. 3 s to reset the LEDs and "TRIP" message.
•
The undervoltage tripping after power on can also
be eliminated by applying three phase rated volt-
ages after power-on and reset the LED and "TRIP"
message.
•
By means of an appropriate parameterisation, the
under voltage function Char1 and Char2 as well as
the parameterised voltage step U1 as under voltage
step can be blocked (refer to 5.7.1). Apply auxiliary
voltage to the external blocking input (terminals
E8/D8) to inhibit the undervoltage functions and
press the <SELECT/RESET> for app. 3 s to reset the
LEDs and "TRIP" message.
6.2 Testing the output relays and LEDs
PLEASE NOTE!
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. „D07-“). By pressing the push button <TRIP>
twice, the display shows the second part of the soft-
ware version of the relay (e.g. „1.00“. The software
version should be quoted in all correspondence. Press-
ing 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 message by pressing the push button <TRIP>
again. All output relays should then be activated and
the self supervision alarm relay (watchdog) be de-
energised one after another with a time interval of 1
second. Thereafter, reset all output relays back to their
normal positions by pressing the push button
<SELECT/RESET>.
6.3 Checking the set values
By repeatedly pressing the push button
<SELECT/RESET>, all relay set values may be
checked. Set value modification can be done with the
push button <+><-> and <ENTER>. For detailed in-
formation about that, please refer to chapter 4.3 of the
description “MR – Digital multifunctional relays”.
As relay input energizing quantities, three phase volt-
ages should be applied to
MRN3-3
relay input cir-
cuits. Depending on the system conditions and the
voltage transformer used, three voltages can be con-
nected to the relay input circuits with either star or
delta connection. In case of a star connection the
phase-to-neutral voltage will be applied to the voltage
input circuits, while the phase-to-phase voltages will be
connected to the voltage input circuits in case of a
delta connection. The voltage input connection must
be set as a parameter, and should correspond with
the actual voltage input connection:
Star connection: Phase-to-neutral voltages will be
measured
and
evaluated.
Delta connection: Phase-to-phase voltages will be
measured
and
evaluated.