1. 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

2. 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!

3. Studies Voltage fluctuation study Harmonic distortion 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

4. 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

5. 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