IEEE Electrification Magazine - September 2014 - 6

By Philippe Ladoux, Joseph Fabre,
and Hervé Caron

Power-Quality
Improvement in AC
Railway Substations
The concept of chopper-controlled impedance.

HE 25-KV/50-HZ AC SINGLE-PHASE SUPPLY IS
a widely used railway system in France with a
length of 9,698 km. Overhead lines are supplied by substations drawing power from two
phases of a three-phase utility. They behave
as nonlinear and time-varying loads and represent one of the
most important sources of voltage unbalance for the electricity-transmission network. In the case of weak networks, railway operators are required to install compensation systems
in substations to satisfy utility regulations and to avoid penalties regarding voltage unbalance and reactive power consumption. The limits are established by the energy provider
with a view to guaranteeing an acceptable power quality to
other customers.
In three-phase networks, the most widely used solutions are
the classical static var (volt ampere reactive) compensators
(SVCs), based on thyristor-controlled reactors (TCRs), and the
static synchronous compensator (STATCOM) based on voltagesource inverters (VSIs). The TCR allows the variation of fundamental lagging current by phase control, counterbalancing large
leading currents from associated fixed capacitors and allowing
continuous compensation of the lagging line. However, this
solution generates a high level of harmonics and requires onerous LC filters. On the other hand, VSIs offer several advantages
over thyristor-based solutions in terms of compensation
dynamics and reduced harmonic distortion. For the last ten

T

Digital Object Identifier 10.1109/MELE.2014.2331792
Date of publication: 29 September 2014
SIGN COURTESY OF WIKIMEDIA COMMONS/DARREN HESTER

6

I E E E E l e c t r i f i cati o n M agaz ine / september 2014

2325-5987/14©2014IEEE



Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2014

IEEE Electrification Magazine - September 2014 - Cover1
IEEE Electrification Magazine - September 2014 - Cover2
IEEE Electrification Magazine - September 2014 - 1
IEEE Electrification Magazine - September 2014 - 2
IEEE Electrification Magazine - September 2014 - 3
IEEE Electrification Magazine - September 2014 - 4
IEEE Electrification Magazine - September 2014 - 5
IEEE Electrification Magazine - September 2014 - 6
IEEE Electrification Magazine - September 2014 - 7
IEEE Electrification Magazine - September 2014 - 8
IEEE Electrification Magazine - September 2014 - 9
IEEE Electrification Magazine - September 2014 - 10
IEEE Electrification Magazine - September 2014 - 11
IEEE Electrification Magazine - September 2014 - 12
IEEE Electrification Magazine - September 2014 - 13
IEEE Electrification Magazine - September 2014 - 14
IEEE Electrification Magazine - September 2014 - 15
IEEE Electrification Magazine - September 2014 - 16
IEEE Electrification Magazine - September 2014 - 17
IEEE Electrification Magazine - September 2014 - 18
IEEE Electrification Magazine - September 2014 - 19
IEEE Electrification Magazine - September 2014 - 20
IEEE Electrification Magazine - September 2014 - 21
IEEE Electrification Magazine - September 2014 - 22
IEEE Electrification Magazine - September 2014 - 23
IEEE Electrification Magazine - September 2014 - 24
IEEE Electrification Magazine - September 2014 - 25
IEEE Electrification Magazine - September 2014 - 26
IEEE Electrification Magazine - September 2014 - 27
IEEE Electrification Magazine - September 2014 - 28
IEEE Electrification Magazine - September 2014 - 29
IEEE Electrification Magazine - September 2014 - 30
IEEE Electrification Magazine - September 2014 - 31
IEEE Electrification Magazine - September 2014 - 32
IEEE Electrification Magazine - September 2014 - 33
IEEE Electrification Magazine - September 2014 - 34
IEEE Electrification Magazine - September 2014 - 35
IEEE Electrification Magazine - September 2014 - 36
IEEE Electrification Magazine - September 2014 - 37
IEEE Electrification Magazine - September 2014 - 38
IEEE Electrification Magazine - September 2014 - 39
IEEE Electrification Magazine - September 2014 - 40
IEEE Electrification Magazine - September 2014 - 41
IEEE Electrification Magazine - September 2014 - 42
IEEE Electrification Magazine - September 2014 - 43
IEEE Electrification Magazine - September 2014 - 44
IEEE Electrification Magazine - September 2014 - 45
IEEE Electrification Magazine - September 2014 - 46
IEEE Electrification Magazine - September 2014 - 47
IEEE Electrification Magazine - September 2014 - 48
IEEE Electrification Magazine - September 2014 - 49
IEEE Electrification Magazine - September 2014 - 50
IEEE Electrification Magazine - September 2014 - 51
IEEE Electrification Magazine - September 2014 - 52
IEEE Electrification Magazine - September 2014 - 53
IEEE Electrification Magazine - September 2014 - 54
IEEE Electrification Magazine - September 2014 - 55
IEEE Electrification Magazine - September 2014 - 56
IEEE Electrification Magazine - September 2014 - 57
IEEE Electrification Magazine - September 2014 - 58
IEEE Electrification Magazine - September 2014 - 59
IEEE Electrification Magazine - September 2014 - 60
IEEE Electrification Magazine - September 2014 - 61
IEEE Electrification Magazine - September 2014 - 62
IEEE Electrification Magazine - September 2014 - 63
IEEE Electrification Magazine - September 2014 - 64
IEEE Electrification Magazine - September 2014 - Cover3
IEEE Electrification Magazine - September 2014 - Cover4
https://www.nxtbook.com/nxtbooks/pes/electrification_december2022
https://www.nxtbook.com/nxtbooks/pes/electrification_september2022
https://www.nxtbook.com/nxtbooks/pes/electrification_june2022
https://www.nxtbook.com/nxtbooks/pes/electrification_march2022
https://www.nxtbook.com/nxtbooks/pes/electrification_december2021
https://www.nxtbook.com/nxtbooks/pes/electrification_september2021
https://www.nxtbook.com/nxtbooks/pes/electrification_june2021
https://www.nxtbook.com/nxtbooks/pes/electrification_march2021
https://www.nxtbook.com/nxtbooks/pes/electrification_december2020
https://www.nxtbook.com/nxtbooks/pes/electrification_september2020
https://www.nxtbook.com/nxtbooks/pes/electrification_june2020
https://www.nxtbook.com/nxtbooks/pes/electrification_march2020
https://www.nxtbook.com/nxtbooks/pes/electrification_december2019
https://www.nxtbook.com/nxtbooks/pes/electrification_september2019
https://www.nxtbook.com/nxtbooks/pes/electrification_june2019
https://www.nxtbook.com/nxtbooks/pes/electrification_march2019
https://www.nxtbook.com/nxtbooks/pes/electrification_december2018
https://www.nxtbook.com/nxtbooks/pes/electrification_september2018
https://www.nxtbook.com/nxtbooks/pes/electrification_june2018
https://www.nxtbook.com/nxtbooks/pes/electrification_december2017
https://www.nxtbook.com/nxtbooks/pes/electrification_september2017
https://www.nxtbook.com/nxtbooks/pes/electrification_march2018
https://www.nxtbook.com/nxtbooks/pes/electrification_june2017
https://www.nxtbook.com/nxtbooks/pes/electrification_march2017
https://www.nxtbook.com/nxtbooks/pes/electrification_june2016
https://www.nxtbook.com/nxtbooks/pes/electrification_december2016
https://www.nxtbook.com/nxtbooks/pes/electrification_september2016
https://www.nxtbook.com/nxtbooks/pes/electrification_december2015
https://www.nxtbook.com/nxtbooks/pes/electrification_march2016
https://www.nxtbook.com/nxtbooks/pes/electrification_march2015
https://www.nxtbook.com/nxtbooks/pes/electrification_june2015
https://www.nxtbook.com/nxtbooks/pes/electrification_september2015
https://www.nxtbook.com/nxtbooks/pes/electrification_march2014
https://www.nxtbook.com/nxtbooks/pes/electrification_june2014
https://www.nxtbook.com/nxtbooks/pes/electrification_september2014
https://www.nxtbook.com/nxtbooks/pes/electrification_december2014
https://www.nxtbook.com/nxtbooks/pes/electrification_december2013
https://www.nxtbook.com/nxtbooks/pes/electrification_september2013
https://www.nxtbookmedia.com