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seconds. This means the input power swing is in-
side the outer blinder (2IBO). Repeat this test for
I
= 4A and 4.75A. The display should show OSB
F
= YES because the power swing is within two
blinders (2IBO and 2IBI).
Step 3.
Apply a current of 4.5A and increase the
IF to 5.5A immediately. The relay should trip with
a display of Z2P = ABC (or Z1P = ABC). This
means the power swing stays inside the blinders
for more than 50 ms and then crosses over 21BI.
For the current of 4.5A, Z1P or Z2P may pick up,
but the relay trips after the OSOT timer times out.
Step 4.
Apply I
of 5.25A suddenly (5% above the
F
calculated value). The relay should trip with a dis-
play Z1P = ABC. The trip time should be
<2 cycles.
2. MAINTENANCE QUALIFICATION TESTS
Maintenance qualification tests will determine if a
particular MDAR unit is working correctly.
2.1
Non-Pilot Maintenance Tests
It is recommended that either Doble or Multi-Amp
test equipment should be used for this test. Refer to
Figure 6-1 for the input voltage and current terminal
connection per configuration 1. Check all jumper po-
sitions on the Interconnect module for rated dc volt-
age.
2.1.1
Front Panel and Metering Check
Step 1.
Turn on rated dc voltage. Check the
FREQ setting; it should match the line frequency
and ct type (CTYP). Apply a balanced 3-phase
voltage (70 Vac); the Alarm 1 relay should be en-
ergized. (Terminal TB4/7 and TB4/8 should be
zero ohms.) The "Relay-in-Service" LED should
be "ON".
Step 2.
Press RESET pushbutton; the green LED
(Volts/Amps/Angle) should be "ON". Press the
FUNCTION RAISE or FUNCTION LOWER push-
button. Read the input voltages and their angles:
VAG = 70 ∠0°
VBG = 70 ∠−120°
VCG = 70 ∠120°
with an error of ± 1 volt and ± 2°.
Step 3.
Press the DISPLAY SELECT pushbutton,
and note that the mode LED cycles thru the five
(5/92)
display modes. Release the pushbutton so that
the SETTINGS mode LED is "ON". Press the
RAISE button to scroll thru the FUNCTION
FIELD to check the settings per Table 6-1 (non-
pilot) or Table 6-3 (pilot). Change the setting, if
necessary, by depressing the RAISE button in
the VALUE FIELD to the desired value and then
pressing the ENTER button.
Step 4.
Press the RESET pushbutton (LED jumps
to Metering mode). Apply 3.0 A to I
of -75°. Read I
from the front display; it should
A
be 3.0 ∠−75° with an error of 5% and ± 2°. Move
the input current from IA to IB or IC terminal.
Read I
or I
to verify the transformer's accuracy.
B
C
2.1.2
Impedance Accuracy Check
Step 5.
Apply voltages to MDAR as follows:
= 30 ∠0°
V
A
= 70 ∠-120°
V
B
= 70 ∠120°
V
C
Apply forward fault current I
The relay should trip for I
play should show "Z1G AG".
Repeat for B and C phases per the following table:
Phase B
= 70 ∠120°
V
A
= 30 ∠0°
V
B
= 70 ∠-120°
V
C
= 4 ∠-75°
I
B
2.1.3
Input Opto-Coupler Check
Step 6.
External Reset
Apply an AG fault as shown in Step 5. The LAST
FAULT LED should be flashing. Press the front
RESET pushbutton. The green LED (Volts/
Amps/Angle) should be "ON". Press the DIS-
PLAY SELECT pushbutton and move the LED
back to LAST FAULT. The fault information "Z1G
AG" should be displayed again. Apply a rated dc
voltage to terminals TB5/5 (+) and TB5/6(-). The
target data should be erased and the display
should show "FTYP". Remove the external reset
voltage.
Step 7.
52b Terminals
Change the CIF setting from "NO" to "CIFT".
I.L. 40-385.1B
with an angle
A
∠-75° suddenly.
A
= 4A ± 5%. The dis-
A
Phase C
= 70 ∠-120°
V
A
= 70 ∠120°
V
B
= 30 ∠0°
V
C
= 4 ∠-75°
I
C
6-11
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