Mikro NX232A User manual

1. DESCRIPTION
NX232A Earth-fault Relay User's Guide
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8. CASE DIMENSIONS
7. CONNECTION DIAGRAMS
a) Earth Fault Relay
Indicators
Mechanical
Outputs
Figure 7: Case Dimensions
Setting Ranges
Low-set setting I>.....................0.10 - 5.00 A (2%-100%)
Time multiplier kt> ...................0.01 - 1.00
High-set setting I>> .................0.10 - 50.0 A (2%-1000%)
High-set definite time t>>.........0.00 - 100 s
Low-set definite time t > ..........0.00 - 100 s
6. TECHNICAL DATA
Ratings
Rated current In......................5 A
Frequency ...............................50 Hz or 60 Hz
Burden ....................................< 0.3 VA at In
Auxiliary Supply
NX232A-240A ........................198~265 VAC
Supply frequency ....................50 Hz or 60 Hz
VA rating .................................3 VA typical
NX232A-110A..........................94~127 VAC
NX232A
R1 R2
NX233A
R1 R2
96 mm
96 mm
Front
110mm
100mm
90mm
90mm
L1
L2
L3
N
NX232A
R1 R2
Auxiliary supply .....................Green LED indicator
Pick up ..................................Red LED indicator
Trip ........................................7 segment LED and
Red LED indicators
NX232A-240AD ......................85~265 VAC/110~370 VDC
The NX232A is a microprocessor based
numerical earth-fault relay. It uses
fundamental frequency current
measurement for excellent harmonic
current rejection. The relay consists of
independent low-set and high-set
elements. The high-set element can be
disabled by the user. The time current
characteristics of the low-set elements
are definite time or five selectable IDMT
curves. The high-set element is a
definite time or instantaneous relay. The
4-digit panel display on the NX232A
allows the display of the present load
current; recorded fault current for last
tripping; and all settings of the relay.
2. LIGHT INDICATORS
The indicators display the status of the system as follow:
Table 1: System Status
1 = ON 0 = OFF X= don’t care, not blinking
B = blinking DT = DATA FUNC = FUNCTION
Indicator
Aux l> l>> FUNC DT Status
0 0 0 0 0 No Auxiliary power supply.
1 0 0 X X Normal condition, no tripping.
1 1 0 X X Low-set overcurrent triggered,
time delay countdown started.
1 0 1 X X High-set overcurrent triggered,
time delay countdown started.
1 B 0 B B Low-set tripped,
DT LEDs show tripped value.
1 0 B B B High-set tripped,
DT LEDs show tripped value.
1 X X 1 B Programming mode.
b) Overcurrent Relay and Earth fault relay (3 phase 4 wire system)
Thermal withstand.....................4 x Incontinuous
Rated voltage ..........................250 VAC
Continuous carry .....................5A (cos
= 1.0)
Expected electrical life ............105operations
Expected mechanical life ........5 x106operations
Environmental conditions
Temperature .......................... -10ºC to 55ºC
Humidity ................................ 5% to 95% non-condensing
Mounting................................ Panel mounting
Dimension (mm) .................... 96(w) x 96(h) x 110(d)
Enclosure protection.............. IP54 at the panel
Approximate weight............... 0.7 kg
Accuracy
Protection thresholds ...............± 5%
Time delay.................................± 5% with a
mimimum of 50ms
Rev M0 (04/19)
(0.00 - 1.00, step 0.01; 1.00-10.0, step 0.10;
10.0-100, step 0.5)

Table 2: FUNCTION Code
3. PUSH-BUTTONS OPERATION
a) Trip test
b) Trip reset
c) View setting
f) Program setting
Only function codes from 4 to 8 can be programmed.
Step 2:
Step 3:
Step 4:
4. OUTPUT CONTACTS
(i) CONTACT R1 - linked to trip signal.
The output contact can be programmed to be either
auto reset type or manual reset type.
For auto reset type, the contact remain activated until
the fault current is removed.
For manual reset type, the contact remain activated.
Use the UP or DOWN key to select the
desired value.
To save the selected value, press the
UP and DOWN key simultaneously again.
It will exit the programming mode with the
data digits displaying new setting.
To exit programming mode without saving the
selected setting, press the RESET key once.
Figure 1: Scroll sequence
5. SOFT SWITCHES
TheNX232A incorporates 5 soft switches for system
configuration. When the function digit shows “8”, the
relay is in soft switch setting mode.
Table 3: Soft switch setting
SW
1
3
4
SVL
00
01
00
01
02
03
00
01
System configuration
Low-set normal inverse curve 3/10.
Low-set long time inverse curve.
Low-set very inverse curve.
Low-set extremely inverse curve.
High-set disabled.
High-set enabled.
“ ”
switch number (SW)
switch value (SVL)
04
Low-set definite time.
200
01
10
11
Contact R2 linked to trip signal auto reset type.
(i) CONTACT R2 - linked to trip or start signal.
Contact R1 linked to trip signal auto reset type.
Contact R1 linked to trip signal manual reset type.
Contact R2 linked to trip signal manual reset type.
Contact R2 linked to start signal auto reset type.
Contact R2 linked to start signal manual reset type.
Low-set normal inverse curve 1.3/10.
05
Figure 4: IDMT Long time Inverse Curve
Figure 3: IDMT Very Inverse Curve
Figure 5: IDMT Extremely Inverse Curve
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.05
Figure 2: IDMT Normal Inverse Curve 3/10
Figure 6: IDMT Normal Inverse Curve 1.3/10
Indicator
FUNCTION DP DATA
0 off Earth-fault current
t blink Last trip elapsed time
0 blink Previous tripped current
4 off Low-set current setting
5 off Low-set time multiplier/delay
setting
6 off High-set current setting
7 off High-set time delay setting
8 off Soft switch setting
The function LED shows "t." and time elapsed after
last trip in day ("d"), hour ("h") and minute ("n"). If
more than 99 days, the display shows "99d" and
"oUr"
e) Trip Current Record
Step 1: Press RESET key until the function digit
shows required function.
Press the "UP" and "DOWN" key
simultaneously to enter programming
mode. The Data digit blinks to indicate the
relay is in programming mode.
5 50 Network frequency 50 Hz
60 Network frequency 60 Hz
Display blinks “T.E.S.T.”, indicators I> and I>> after
test tripped.
Display off Mode
To toggle display off mode, press “RESET” for 10
seconds. When display off mode enabled, the display
will switch off after 6 minutes if no key is pressed.
d) Last Trip Elapsed Time
The NX232A has two sets of output contact:
By default the most recent ("1") trip current is shown.
Press "UP" or "DOWN" key to show the previous
("2") and oldest ("3") trip current.
When the relay is not under tripped condition,
pressing the “RESET” key will scroll through the
various functions.
Press the “RESET” key to reset the relay when
tripped
Press and hold the “TEST” key for 3.5 seconds to
stimulate a trip.