Connecting the London underground to the public grid: solutions for safeguarding of power quality

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Connecting the London underground to the public
grid solutions for safeguarding of power quality
R Grünbaum, M Noroozian, A Palesjö, ABB Presented
by T Larsson ABB
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Background

• London Underground Ltd. (LUL) closing down an old
  gas/oil power station from 1905
• LUL load, mostly diode converters, to be
  connected to London Electricity public grid
• Power quality!
• Voltage fluctuations
• Harmonics
• Study!

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Studies

• Voltage fluctuation study
• Traction load, big changes in power
• Find SVC sizes and verify their locations
• Harmonic distortion study
• Determine TCR and filter size (rating), number,
  configuration and placement
• 5 different SVCs required

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SVC Design

• TCRs and filters given by studies
• BCT thyristors and iron core reactors for space
  saving and low magnetic fields (SVCs in
  residential areas)
• Remote measurement of voltage

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Conclusions

• Studies show that
• required voltage fluctuation will be met
• harmonic distortion will be within specification
• The SVCs and harmonic filters have been installed
  and are in service
• Measurements show good agreement with simulations
• Phasing the London Underground into the public
  grid is complete