John Aitken, Aitken & Partners Consulting Engineers - Electromagnetic Compatibility (EMC) for safety
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EMC for Safety John Aitken Aitken & Partners
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John Aitken BE MIRSE SMIEEE, Director, Aitken & Partners Consulting Engineers delivered the presentation at ARA’s Telecommunications & Train Control Conference 2014. The ARA’s Telecommunications & Train Control Conference 2014 brought together passenger and freight rail operators, transport agencies, track owners, regulators and technology suppliers to assess telecommunications solutions and explored the capabilities of a shared future. For more information about the event, please visit: http://bit.ly/traincontrol14
Transcript of John Aitken, Aitken & Partners Consulting Engineers - Electromagnetic Compatibility (EMC) for safety
EMC forSafety
John Aitken
Aitken & Partners
Electromagnetic Compatibility
Ability to function satisfactorily in its electromagnetic environment
Electromagnetic Compatibility
Ability to function satisfactorily in its electromagnetic environment
without introducing
intolerable electromagnetic disturbances to
anything in that environment.
IEC 600500-826
“… must be designed, built and
maintained with regard to EMC in
order that they operate safely
throughout their operational life.
Safety
Freedom from
unacceptable
risk of harm.
EN 50126
unacceptable
risk of harm
Disturbances
intolerable
disturbances
conducted
disturbance
Midya
Midya
inductive
disturbance
Armstrong
Hill
radiated
disturbance
EN 50238
Simple
concept
✗
Don’t let unwanted energy out of component
Don’t let unwanted energy into component
Minimise unwanted energy
Make systems compatible
✗
safety
margin
Standards
• EN 50121 – Railway System
• EN 50238 – Train Detection
• EN 50500 – Effects on People
• ARPANSA No 3 – Australian Law
Standards
• Precise tests of one thing at a time
• Repeatable results
• Laboratory conditions
• Nothing like a railway!
EN 50121
• Part 1 – General
• Part 2 – Emission of the entire railway
• Part 3 - 1 Rolling Stock – Train
• Part 3 – 2 Rolling Stock – Components
• Part 4 – Signalling and Telecommunications
• Part 5 – Fixed Power.
Immunity Standards
Immunity Standards
Radiated Emissions
Conducted Emissions
ECP – Right side failure
Sudden, unexplained emergency brake application
Often at the same place – but not always
Many Observations
• Only with ECP
• Not always, but usually in electrified area
• Usually associated with dynamic brake
• More often on the steep grades on the mountain range
• Happens sometimes when you cut off power
• Very frequently at the port.
The cause – traction harmonics
• Always there:
– Absorbed into traction circuit under load
– Distributed on overhead system when in dynamic brake or stationary
Finding the problem
• The problem was found – a design issue in a power supply.
• The balanced line for ECP was not balanced at all frequencies because the power supply designer put in a component to pass an EMC test. The component shunted unwanted frequencies from the power supply to ground.
Finding the problem
• The problem was found – a design issue in a power supply.
• The balanced line for ECP was not balanced at all frequencies because the power supply designer put in a component to pass an EMC test. The component shunted unwanted frequencies from the power supply to ground.
Good design
• Standards prescribe tests to identify known problems
• The tests cover a limited number of circumstances
• Tests are done sequentially.
• Real life is not like that. Things happen.• They don’t check the standards first!• Careful, consistent design is essential.
Thank you
