hear there are new techniques of circuit breaker testing

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

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Circuit Breaker Testing
>
Circuit Breakers – Design and standards
Tests on Circuit Breakers
CIBANO 500

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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.
Definition of Circuit Breaker
Ideal switch:
closed open
R = 0 Ω R = ∞Ω

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Purpose of Circuit Breakers in Power Systems
>
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
Busbar
Disconnector
Circuit Breaker
Power
Transformer
x
Circuit Breaker
Network

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Circuit Breaker Components
Source: ABB, [RUS07]

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A: interrupter chamber
B: insulated support column
C: support structure
D: central cubical
E: wiring
F: operating mechanism
Source: Siemens
Circuit Breaker Components

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Standards – ANSI
> C37.04-1999
> Standard ratings defined
> C37.06-2000
> Schedule of preferred ratings
> C37.09-1999
> Type tests
> Routine tests
> C37.081, C37.082,
IEEE 693

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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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IEC - timing definition

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Circuit Breaker Testing
Circuit Breakers – Design and standards
>
Tests on Circuit Breakers
CIBANO 500

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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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1. Minimum pick-up test
2. Static resistance or contact resistance test (µOhm)
3. Timing of main and auxiliary contacts
a. different operations (O, C, OC, CO, OCO, COCO, OCOCO,...)
b. undervoltage test
c. coil currents
4. Motor current
5. Contact travel (motion) of main contacts
6. Dynamic contact resistance (DRM)
Typical tests on circuit breakers

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1. Minimum Pick-up Test

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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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2. Contact Resistance Test
Conventional Setup

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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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3a. Timing Test
>
Connect to all main contacts
>
Connect to trip & close coil
>
Voltage supply required
Time-consuming and
error-prone
Conventional Setup

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3a. Timing Test - Measured Values
Open Time, Close Time, Contact Spread, Phase Spread, Trip-Free Time, Reclose Time

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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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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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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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5. Contact Travel
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Functional Breaker Model

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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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6. Dynamic Resistance Measurement (DRM)
> Recording the contact resistance during breaker
operation (resistance over time)
> Combination of contact resistance, timing and
travel measurements
1.Inject high current
2.Start recording A & V
3.Operate Circuit Breaker
4.Calculate Resistance

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6. Dynamic Resistance Measurement (DRM)
Use DRM to find out
>
Problems with contact fingers
>
Lubrication problems
>
The arcing contact length
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6. DRM Diagnosis: arcing contact length
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motion
dynamic resistance
coil current
arcing contact length
main contact
ms

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Circuit Breaker Testing
Circuit Breakers – Design and standards
Tests on Circuit Breakers
>
CIBANO 500

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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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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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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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Unique connection concept
CIBANO 500 CB TN3
CB MC2

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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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Unique connection concept

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Unique connection concept

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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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Powerful software support
>
Primary Test Manager software supports all tests
>
One combined test report for all tests

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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 / 44.1
lbs)

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