1. Circuit breaker testing – New Approach
Thomas Renaudin
SEEEI conference *

2. Circuit Breaker Testing
Circuit Breakers – Design and standards
Tests on Circuit Breakers
CIBANO 500
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3. Definition of Circuit Breaker
Basically a circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to immediately discontinue electrical flow.
Ideal switch:
closed open
R = 0 Ω R = ∞Ω
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4. Purpose of Circuit Breakers in Power Systems
Network
Minimize losses in closed position
Open and close on command
Open or close a circuit to connect the power to/from the transmission line (O - break, C - make)
Open a circuit for planned maintenance (O - break)
Open a circuit at system fault to protect the system behind the circuit breaker (O break, O-C reclose, O-CO, auto-reclose)
Isolate between poles, open contacts and earth x
Circuit Breaker
Busbar
Disconnector x
Circuit Breaker
Power
Transformer
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5. Circuit Breaker Components
Source: ABB, [RUS07]
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6. Circuit Breaker Components
A: interrupter chamber B: insulated support column C: support structure D: central cubical E: wiring F: operating mechanism
Source: Siemens
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7. Standards – ANSI C37.04-1999 Standard ratings defined C37.06-2000
Schedule of preferred ratings C
Type tests
Routine tests
C37.081, C37.082, IEEE 693
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8. Standards – IEC IEC 62271-100, 2001 Type, routine & field tests
Timing definitions
Guide for selection and specification
IEC 60694, 2001
Normal service conditions
Schedule of preferred ratings
Altitude correction
IEC 60427, IEC 60815, IEC 60529, IEC 61166, IEC 61233
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9. IEC - timing definition
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10. Circuit Breaker Testing
Circuit Breakers – Design and standards
Tests on Circuit Breakers
CIBANO 500
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11. What is usually needed to test breakers
Timing Analyzer
µΩ - Meter
CB Supply
Rewiring for each test
Individual µΩ-Measurement for each interrupter
Collect data for test report
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12. Typical tests on circuit breakers
Minimum pick-up test
Static resistance or contact resistance test (µOhm)
Timing of main and auxiliary contacts
different operations (O, C, OC, CO, OCO, COCO, OCOCO,...)
undervoltage test
coil currents
Motor current
Contact travel (motion) of main contacts
Dynamic contact resistance (DRM)
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13. 1. Minimum Pick-up Test
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14. Indicates the lowest voltage to operate the trip or close coil
1. Minimum Pick-up Test
Indicates the lowest voltage to operate the trip or close coil
Start at a certain voltage level
Try to operate
If not working increase voltage and try again
Ramp the voltage pulse until minimum voltage is reached with which the circuit breaker switches
Everybody has a „selfmade“ solution for this test
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15. 2. Contact Resistance Test
Conventional Setup
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16. 2. Contact Resistance Test
Test is performed with a µOhm-Meter
A lot of different test devices on the market (weight, handling, output current and accuracy)
Inject a high current
Measurement of a small voltage in a noisy environment
Use 4-wire technique to connect
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17. Connect to all main contacts Connect to trip & close coil
3a. Timing Test
Connect to all main contacts
Connect to trip & close coil
Voltage supply required
Conventional Setup
Time-consuming and
error-prone
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18. 3a. Timing Test - Measured Values
Open Time, Close Time, Contact Spread, Phase Spread, Trip-Free Time, Reclose Time
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19. 3b. Timing undervoltage condition
Coils are normally driven by station battery
What happens if battery condition is not the best
Perform a test with reduced supply voltage (e.g. 80 %)
Check times for under voltage
does it work anyhow
are there any delays compared to nominal voltage?
Measure the overall times and compare to manufacturer values
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20. Important tool in circuit breaker analysis
3c. Coil Current
Important tool in circuit breaker analysis
Detect potential problems in actuating coils
Reveal information on power supply
Comparison is best method of analysis
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21. Connect source to charging motor or use current clamp
4. Motor Current
Connect source to charging motor or use current clamp
Check charging times and charging currents
Compare with previous measurements
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22. Functional Breaker Model
5. Contact Travel
Functional Breaker Model
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23. 5. Contact Travel - Travel Measurement to find out:
Mechanical defects of the cinematic chain
Overall mechanical performance
Slow operation due to jammed mechanism
Deterioration of mechanical damping
Contact wear
Arcing contact length (in combination with DRM)
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24. 6. Dynamic Resistance Measurement (DRM)
Recording the contact resistance during breaker operation (resistance over time)
Combination of contact resistance, timing and travel measurements
Inject high current
Start recording A & V
Operate Circuit Breaker
Calculate Resistance
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25. 6. Dynamic Resistance Measurement (DRM)
Use DRM to find out
Problems with contact fingers
Lubrication problems
The arcing contact length
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26. 6. DRM Diagnosis: arcing contact length
main contact
motion
arcing contact length
dynamic resistance
coil current ms
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27. Circuit Breaker Testing
Circuit Breakers – Design and standards
Tests on Circuit Breakers
CIBANO 500
© OMICRON

28. Conventional Setup for Circuit Breaker Testing
Rewiring between micro- ohm measurement and timing tests
Lots of cables
Time-consuming and error-prone
Long test cables create inductive loops which catch interferences
External supply or station battery required
Mirco-ohm measurement
Timing Tests
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29. CIBANO 500 – 3-in-1 Test System
Timing analyzer
Possible operations: O, C, CO, OC, O-CO, CO-CO, O-CO-CO
Motion measurement is possible in parrallel
Micro-ohm meter
Static AND dynamic contact resistance test
Powerful coil and motor stabilized supply
Coil/motor current analysis
Undervoltage condition test
Minimum pick-up test
Tests are possible without station battery
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30. CIBANO 500 – one system for all types of breakers
Medium-voltage circuit breakers
High-voltage circuit breakers (Live Tank)
High-voltage circuit breakers (Dead Tank)
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31. Unique connection concept
CB MC2
CIBANO 500
CB TN3
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32. Modular concept for simplified testing – Main Contact Module CB MC2
2 high-current outputs and 2 sensitive voltage measurement channels
Keeps high-current cables as short as possible
minimizing the weight of the necessary cables
A digitized measuring signal is produced directly at the interrupter keeping analog cables as short as possible
very low noise interference
Only one connection cable to the main unit
fast set-up and reduced risk of wiring errors
Both sides grounded test possible
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33. Unique connection concept
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34. Unique connection concept
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35. Modular concept for simplified testing – Transducer Node CB TN3
Accessory for motion/contact travel test
3 analog and digital channels for data acquisition of linear or rotational motion sensors
Interference-free digital transmission of results via one cable
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36. Powerful software support
Primary Test Manager software supports all tests
One combined test report for all tests
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37. Benefits of all-in-one OMICRON approach
3-in-1 system combines:
timing analyzer
micro-ohmmeter
powerful AC/DC supply
One wiring for all test: all-in-one / all-in-once
One system for medium- and high-voltage circuit breakers
Immunity to interference due to short test cables
One combined report for all tests
Light-weight test system for on-site testing (20 kg / lbs)
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38. © OMICRON