L2234
L2778
Emax
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Model
Scale
Page No.
Doc. No.
Apparatus
1SDH000460R0002
12.7.2 Troubleshooting
The following table lists a series of typical service conditions, to help you understand and solve hypothetical faults or malfunctions.
N.B.:
1.
Before consulting the following table, check for a few seconds for any optical signals provided by the LEDs.
2.
FN indicates the normal operation of the PR121/P.
3.
If the following suggestions fail to solve the problem, please contact the ABB SACE customer support service.
N o .
Situation
Possible causes
Suggestions
1
The trip test cannot be run
1. The busbar current is > 0
1. FN
2. The TC is not connected
2. Check TC connection
(see par. 12.4.2)
3. PR030/B is not connected
3. Connect the PR030/B unit
2
Trip times lower
1. Threshold too low
1. Correct threshold
than expected
2. Curve too low
2. Correct curve
3. Incorrect neutral selection
3. Correct neutral adjustment
3
Trip times higher
1. Threshold too high
1. Correct threshold
than expected
2. Curve too high
2. Correct curve
3. Curve type "t=k/I
2"
3. Select curve type "t=k"
4. Incorrect neutral selection
4. Correct neutral adjustment
4
Rapid trip, with I3=Off
Iinst tripped
FN short-circuit with high I
5
Earth fault current beyond threshold
G function automatically inhibited
FN
but no trip occurs
6
Expected trip does not happen
Function OFF
FN enable protection function
if necessary
7
LEDs irregularly turned on
See par. 12.7.1
8
Unexpected trip
See par. 12.7.1
9
L LED (orange) flashing
FN
12.7.3 In the case of a fault
If the PR121/P is suspected of being faulty, there are signs of malfunctions or it has generated an unexpected trip, we advise
you to strictly follow the recommendations below:
1. Press the "i Test" button (within 48 hours of opening the CB) and make a note of which LED is on, also recording the type of CB, the number
of poles, any connected accessories, the In, and the serial number (see par. 12.5).
2. Prepare a brief description of the opening (what LEDs were displayed?, when did it happen?, how many times?, was it always under the same
conditions? what type of load? what current? is the event reproducible?)
3. Send/communicate all the information collected, together with the circuit diagram for the circuit-breaker, to your nearest ABB Customer Support
service.
The more the information given to the ABB Customer Support service is complete and accurate, the easier the technical analysis on the problem
encountered will be, enabling us to take all action to help the user without delay.
12.8 Accessories
12.8.1 ABB SACE PR010/T test and configuration unit
Testing with the SACE PR010/T unit enables you to monitor the proper operation of thresholds and trip times of the protection functions "L", "S",
"I", and "G". The test unit is wired to the relay by a dedicated connector (see ref. 26 par. 12.5).
12.8.2 BT030 communication unit
Using the BT030 wireless communication unit, the PR121/P can be connected by radio to a hand-held PC (PDA) or normal PC, thus extending
the amount of information available to the user. In fact, using the SD-Pocket communication software by ABB SACE, you can read the values of
the currents flowing through the circuit-breaker, the value of the last 20 currents broken and the protection settings.
12.8.3 PR021/K and HMI030 units
The PR121/P can also be connected to the optional PR021/K external signalling unit (see par. 16), for the signalling by means of no-potential power
contacts of alarms and tripped protections, and to the HMI030 switchboard front unit to view various kinds of information on the display.
12.8.4 PR030/B power supply unit
The PR030/B power supply unit is a separate unit for powering the relay, auto test, trip test and checking with CB open.
