Mikro NX300A User manual

INDICATORS
Pre-fault alarm ...........................................................… Red indicator
Leakage trip delay time .............................................… Red indicator
Leakage trip ..............................................................… 7-segment display and red indicators
Manual test trip .................................................……......….. 7-segment display and red indicators
ZCT connection fault ................................................…….... 7-segment display and red indicators
Trip records .................................................................. 7-segment display
Real-time leakage current ............................................ 7-segment display
ZERO-PHASE CURRENT TRANSFORMERS
To operate with Mikro's ZCT series of current transformers
NX300A & NX300EA Earth Leakage Relay
User’s Manual
A BRIEF OVERVIEW
MECHANICAL
Mounting....................................................................… Standard DIN 96x96mm panel mount
Approximate weight....................................................... 0.58kg (excluding ZCT)
9. CONNECTION DIAGRAMS
AUX
L1 L2 L3 N
PE
N
L
MIKRO
ZCT
The EARTH wire
NX300A
must not pass
1
2
3
4
5
6
7
8
through the ZCT
SHUNT
TRIP
CONTACT
TRIP
NC
NO C
9 10
11
12
13
14
15
16
LOAD
AUX
REMOTE
L1 L2 L3 N PE
N
L
RESET
MIKRO
ZCT
NX300EA
The EARTH wire
must not pass
1
2
3
4
5
6
7
8
through the ZCT
CONTACTOR
TRIP
ALARM
POSITIVE SAFETY
CONTACT
CONTACT
CONTACT
NC NO
C
NO
C NC NO C
9
10
11
12
13
14
15
16
LOAD
a - DATA display
b - Trip status indicator
c - Alarm status indicator
d - DP2 indicator
e - Decrement button
f - Increment button
g - RESET button
h - TEST button
i - Model
j - DP1 indicator
k - FUNC display
1. DESCRIPTION
Symbols
In
-
Sensitivity setting
t
-
Time delay setting
Flt 1 -
Fault record #1 (Most recent)
Flt 2 -
Fault record #2
Flt 3 - Fault record #3 (Oldest)
The NX300A and NX300EA are microprocessors based earth leakage relays designed for measure
the low-level current flowing from the live part of the installation to the earth in the absent of the
insulation fault. A zero phase current transformer is connected to the relay and function as the sensor
for sensing the leakage current. All conductors of the circuit to be protected shall go through the ZCT.
For better fault preventive control of the system or equipment to be protected, NX300EA series comes
with a pre -fault alarm contact and a positive safety contact. The pre-fault alarm contact is activated
whenever the leakage current exceed 50% of the sensitivity setting. While the positive safety contact
is activated if the relay is power up and function correctly. The NX300EA series also built-in a digital
input port for remotely reset the relay after leakage fault trip, manual test trip or ZCT connection fault.
10. CASE DIMENSION
* Applicable to NX300EA series only
90mm
70mm
96mm
96mm
SIDE
FRONT PANEL
CUTOUT
91±0.5mm
91±0.5mm
∆
∆
EARTH LEAKAGE RELAY
NX 300A
TEST RESET
TRIP
ALARM
a
b
c
d
e
f
g
h
k
j
i

2. LIGHT INDICATORS
[Trip]
[Alarm]
[FUNC]
[DP1]
[DATA]
Status
LED
LED
display
indicator
display
0
0
0
0
0
No auxiliary supply
0
0
X
X
1
Normal condition, no tripping
0
B
X
X
X
Leakage current > 50% of the I∆n
0
FB
X
X
X
Leakage current > 85% of the I∆n. Trip time delay running
1
1
0
0
B
Relay tripped
0
0
1
0
1
Scroll through setting
0
0
1
1
1
Scroll through records
0
0
B
0
1
[DATA] programming mode
1
1
X
X
“Ct”
ZCT connection fault
X
X
X
X
“tSt”
Manual trip test
Table 1: Relay status displayed
1 = ON 0 = OFF X = Don't care
B = Normal blink FB = Fast blink
3. PUSH BUTTONS OERATION
a. Integral Trip Test:
•Press the [TEST] button and hold for 3.5s to perform an integral test on the relay ranging from the
analog sensing circuitry to output contact(s) of the relay as well as the relay indicators and display.
•During the testing process, the first 2s is to simulate the pre-fault alarm condition then follow by 1.5s
testing on the trip time delay. End of time delay, relay trip.
b. Leakage Fault Trip Reset: / Manual Test Trip Reset:
•Press the [RESET] button once or through digital input port.
c. ZCT Connection Fault Reset:
•Press the [RESET] button once or through digital input port.
•Reset is inhabited if the fault is not rectify.
d. Parameters Viewing:
•When the relay is operate normal and healthy condition, press the [RESET] button to step through
the various functions.
•When step through the parameters, press [RESET] button and hold for 1.5 second to jump direct to
the default [FUNC].
[FUNC]
[DP1]
[DP2]
Symbols
Description
Blank
Off
Note 1
Real-time leakage current display (Default)
1
Off
X
I∆n
Sensitivity setting (A)
2
Off
X
∆t
Trip time delay setting (second)
3
Off
X
Note 2
Inhabit ZCT connection fault trip
A
On
Note 1
Flt 1
Fault record #1 (Most recent)
b
On
Note 1
Flt 2
Fault record #2
c
On
Note 1
Flt 3
Fault record #3 (Oldest)
Table 2: List of [FUNC] code displayed
Note 1: If DP2 is OFF. The unit for the [DATA] displayed is in mA.
If DP2 is ON. The unit for the [DATA] displayed is in ampere (A).
Note 2: Symbol not show in front panel display
e. Parameters Setting
•Step 1: Press [RESET] button to step to desired [FUNC] or parameter.
•Step 2: Press [▲] and [▼] buttons simultaneously and hold for 1.5s to enter programming mode.
The [FUNC] digit blink to indicates the relay has enter into the programming mode.
•Step 3: Press [▲] or [▼] button to increase or decrease the parameter value.
•Step 4: To save the selected value, press [▲] and [▼] buttons simultaneously and hold for 1.5s. It
will exit the programming mode with [DATA] displaying the new setting.
To exit programming mode without saving the selected setting, press the [RESET] button once.
4. DIGITAL INPUT PORT *
a. These digital port is for remotely reset the relay when tripped or ZCT connection fault.
b. To reset the relay, make a connection between terminals 4 and 5 of the relay.
5. OUTPUT CONTACTS
Trip Contact
Activated and latch by leakage fault trip, manual test trip or ZCT connection fault
Positive Safety
Activated when the relay is power up and function correctly with no tripping.
Contact *
Pre-fault Alarm
Activated when the measured leakage current > 50% of the I∆n and self reset when the
Contact *
measured leakage current < 45% of the I∆n
Activated and latch when the relay is tripped
Table 3: Output contact description
6. RECORDS
a. Record the 3 latest tripped faults current or “tSt” for manual trip test.
b. The records are stored in non-volatile memory.
c. To clear the entire record database:
•Step 1: When the relay is healthy, press [RESET] button to step to most recent trip fault record or
[FUNC] digit shown “A”.
•Step 2: Press [▲] and [▼] buttons simultaneously and hold for 3.5s or the [DATA] show “0”. It will
clear the entire fault records database.
7. TECHNICAL DATA
AUXILIARY SUPPLY
NX300A-230(6) / NX300EA-230(6)............................... 184~276 VAC
NX300A-110(6) / NX300EA-110(6)............................... 94~127 VAC
NX300A-240AD(6)/NX300EA-240AD(6)……………… 85~265VAC/110~340VDC
Rated frequency............................................................. 50Hz or 60Hz
VA rating......................................................................... 3 VA typical
SETTING RANGES
Sensitivity adjustment..................................................... 30mA, 50mA,
0.10~1.00A (step=50mA),
1.00~10.0A (step=1.00A)
Delay time adjustment.................................................... Instantaneous,
0.1~3.0s (step=0.1s)
RECORD
Fault record.................................................................... 3 latest trip fault current or “tSt” for manual trip test
Storage........................................................................... Non-volatile memory
DIGITAL INPUT PORT
Remote reset.................................................................. N.O. Dry contact
OUTPUT CONTACTS
Contact rating................................................................. 5A 240V ACI
Contact arrangement...................................................... Change over
Expected electrical life.................................................... 50,000 at rated current
Expected mechanical life................................................ 5,000,000 operations