FUTURE DC RAILWAY ELECTRIFICATION SYSTEM

Go for 9kV

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

Existing Railway Electrificationsin Europe

No Electrifications

1905 1915 1950 20xx

15 kV 16,7 Hz - MVAC❖Specific generation and

distribution grid.❖Bulky substation transformers.✓No phase break.✓ AC circuit breakers.

1.5 kV or 3 kV - DC❖AC/DC conversion in substation.❖Overhead line cross-section.❖DC circuit breakers.✓ Simple traction chain embedded.✓ Substations in parallel.

25 kV 50 Hz - MVAC❖Single-phase substations.❖Neutral sections.❖Complex traction chain.✓ Supply from public grid.✓ AC circuit breakers.✓Overhead line cross-section

9 kV-MVDC

INTRODUCTION

Observation : In France, 6000 km of overhead-line supplied by 1.5 kV DC system need to be renovated:

➢ The same electrification system or converted to 25 kV AC.

➢ New MVDC electrification system.

2

?

UIC Workshop on Energy Efficiency11/0/2019 Rotterdam

Why looking to a MVDC Railway Electrification System ?

To mix advantages of the existing electrification systems- Power sharing between substations. - Three-phase power supply from public grid.- Simple locomotive on-board power converter. - Light overhead line and no inductive voltage drop.

Power electronics is mature enough - HVDC power converters.- Solid State DC Circuit Breakers.- MV drives for industrial motors are commercially available.- SiC power semi-conductors enable the realization of compact MV traction converters.

A real breakthrough for the future of rail transportation- A solution for countries not yet electrified.- A solution for DC lines renewal (copper savings, energy efficiency increase).- Easier integration of MVDC smart grid concept.

INTRODUCTION

3UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

INTRODUCTION

Determining substations distance and overhead-line cross-section

Computational Algorithm

Line parameters

Electrical and thermalconstraints

- Railroad traffic- Train power - Voltage range

Overhead-line cross-section

versus substation spacing

New Medium-Voltage DC Railway ElectrificationComputation Results

4

𝑃 = 3𝑀𝑊𝑣 =80km/h

Tim. = 5 min.

𝑃 = 12𝑀𝑊𝑣 = 280𝑘𝑚/ℎTim. = 5 min.

A. Verdicchio, P. Ladoux, H. Caron and C. Courtois, "New Medium-Voltage DC RailwayElectrification System," in IEEE Transactions on Transportation Electrification, vol. 4, no. 2, pp. 591-604, June 2018.

100

150

200

300

400

500

600

700

20 25 30 35 40 45 50 55 60 65

Substations spacing (km)

Cat

enar

y c

ross

-sec

tio

n (m

m2)

High-speed transport

6 kV 7,5 kV

Grs= 0,075 S/km

10,5 kV

9 kV

20 25 30 35 40 45 50 55 60 65100

150

200

300

400

500

600

700

Substations spacing (km)

Cat

enar

y c

ross

-sec

tio

n (m

m2)

Suburban transport Upper limit

4,5 kV 6 kV 7,5 kV9 kV

Grs= 0,075 S/km

10,5 kV

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

CONTENT

5

➢ Electrification Conversion Strategy (from 1.5 kV DC to 9 kV DC)

➢ Case Study (Bordeaux-Hendaye line)

➢ Conclusion and future work

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

ELECTRIFICATION CONVERSION STRATEGY

Existing solution: 1.5 kV DC Railway Electrification System

10/15 km

Overhead line

• Low substation distance.• Heavy overhead line, cross-sections up to 1000mm2.• System originally developed for low power rolling stocks.

Rectifier

Transformer

Substation 1.5 kV

Tracks

6

DCAC

DCAC

DCAC

DCAC

DCAC

DCAC

1.5 kV

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

ELECTRIFICATION CONVERSION STRATEGY

Catenaries

Rectifiers

Transformer

Tracks

Feeder

• 9kV transformer-rectifier groups and feed-wires are added.• Intermediate 1.5kV transformer-rectifier groups are replaced by DC-DC PETs.

PET : Power electronics transformer.

First step: Three-wire supply system 9 kV -1.5 kV

7

1.5 kV

9 kV

DCAC

DCAC

DCAC

DCAC

DCAC

DCAC

DCAC

DCAC

DCDC

DCDC

DCDC

DCDC

Substation

9kV -1.5 kV

10/15 km

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

ELECTRIFICATION CONVERSION STRATEGY

Final step: 9 kV DC Railway Electrification System

• Overhead-line supplied by 9kV substations.• 1.5 kV DC transformer-rectifier groups and PETs completely removed.• DC-DC PETs or/and MVDC converter embedded in the traction-unit.• The overhead-line cross-section is reduced.• The number of substations is reduced.

Catenaries

Rectifier

Transformer

Tracks

8

d 40km < d < 100km

DCAC

M

9 kV

DCAC

DCDC

DCAC

AC

DC

Substation 9 kV DC

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9

CONTENT

➢ Electrification Conversion Strategy (from 1.5 kV DC to 9 kV DC)

➢ Case Study (Bordeaux-Hendaye line)

➢ Conclusion and future work

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

40 60 80 100 120 140 1601200

1300

1400

1500

1600

1700

1800

km

(V)

km 47 km 67 km 89 km 108 km 126 km 147LAMOTHE St PAUL

1.5 kV

DCAC

DCAC

DCAC

DCAC

DCAC

DCAC

10

Original power supply 1.5 kV

5th International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference.

Future DC Railway Electrification System – Go for 9kV

CASE STUDY : Bordeaux-Hendaye line

• Average overhead line cross-section = 850mm2

• 6 substations

40

60

80

100

120

140

160

18:03 18:40(hh:mm)

(km

)

Trains from St. Paul to Lamothe

Trains from Lamothe to St. Paul

Railroad traffic

0

1

2

3

4

5

18:03 18:40(hh:mm)

(MW

)

Absorbed Power by trains

∆𝑉 = 30%

Pantograph voltages

Traction Power derating Under 1300 V

Rails

Contact wires

Messenger wires

Feed-wire(s)

40 60 80 100 120 140 1601200

1300

1400

1500

1600

1700

1800

(V)

(km)40 60 80 100 120 140 160

1200

1300

1400

1500

1600

1700

1800

km

(V)

11

Three-wire supply system 9 kV/1.5 kV

CASE STUDY : Bordeaux-Hendaye line

• Average overhead line section 850 mm2 per track.

• 2 substations and 4 PETs.

• Feed-Wires : 2 x 150 mm2.

DCDC

km 47 km 67 km 89 km 108 km 126 km 147

LAMOTHE St PAUL

9 kV

1.5 kV

DCAC

DCAC

DCAC

DCAC

DCDC

DCDC

DCDC

∆𝑉 = 25%

0

2

4

6

8

(MW

)

18:03 18:40

(hh:mm)

Supplied power by rectifier groups 9kV DC

0

2

4

6

(MW

)

18:03 18:40(hh:mm)

Supplied power by converters DC-DC

0

1

2

3

4

(MW

)

18:03 18:40(hh:mm)

km 47

km 147

Supplied power by rectifier groups 1.5kV DC

Pantograph voltages

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

km 47 km 147

LAMOTHE St PAUL

km 53 km 77 km 97 km 118 km 138

9 kV

DCAC

DCAC

M

100 km

DC

ACMDC

AC

12

CASE STUDY : Bordeaux-Hendaye line

9 kV DC

• Overhead line cross-section per track : 266 mm2

• Substations distance : 100 km

60 12080 140

(kV

)

16010040

9

9.4

9.8

10.2

10.6

(km)

Pantograph voltages

∆𝑉 = 12%

18:03 18:40(hh:mm)

9

7

1

3

5

(MW

)

km 47

km 147

Power supplied by substations 9kV DC

Rails

Contact wire

Messenger wire

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

Comparison between 9 kV and 1.5 kV system

CASE STUDY : Bordeaux-Hendaye line

22:0040

60

80

100

120

140

160

14:00 (hh:mm)

(km

)

Trains from St. Paul to LamotheTrains from Lamothe to St. Paul

Railroad traffic for half day

0

1

2

3

4

5

6

7

14:00 22:00(hh:mm)

(MW

)

Absorbed Power by trains

13

Specifications

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

Comparison between 9 kV and 1.5 kV system

CASE STUDY : Bordeaux-Hendaye line

< 𝐴1.5𝑘𝑉 >= 850 𝑚𝑚2

9kV DC Overhead-Line1.5kV DC Overhead-Line

Equivalent overhead-line cross-section

𝐴9𝑘𝑉 = 266 𝑚𝑚2

𝐴9𝑘𝑉< 𝐴1.5𝑘𝑉 >

≈ 0.3

Rails

Contact wire

Messenger wire

Rails

Contact wires

Messenger wires

Feed-wire(s)

Overhead-line efficiency

𝜂9𝑘𝑉 = 0.95

𝜂1.5𝑘𝑉 = 0.89

Total Energy supplied by substations

20

25

30

35

40

1.5 kV DC 9 kV DC

Absorbed energy by trains

Losses

2.5 MWh per half day

Maximum Power supplied by substations

0

2

4

6

8

10

km42 km67 km89 km108 km126 km148

(MW

)UIC Workshop on Energy Efficiency

11/02/2019 Rotterdam

CONTENT

14

➢ Electrification Conversion Strategy (from 1.5 kV DC to 9 kV DC)

➢ Case Study (Bordeaux-Hendaye line)

➢ Conclusion and future work

UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

CONCLUSIONS and FUTURE WORK

15

Moving to 9kV allows:

• Reducing the copper of the overhead line ( 70% of the cross-section that is about 20 M€ saved for 100 km).

• Reducing the number of substations compared to 1.5kV DC (about 60% less installed power).

• Increasing efficiency ( about 6%).

• Saving 2 GWh per year for 100 km (about 150 k€ per year).

Outlook:

• Very attractive for countries that need to develop an electrified railway network.

• A DC system towards which European railway companies can converge within a long-term.

Work in progress:

• Development of a Power Electronics Transformer based on SiC MOSFETs.

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The Dream

15UIC Workshop on Energy Efficiency11/02/2019 Rotterdam

DCDC

DCDC

DCDC

DCDC

DCDC

DCDC

DCAC

DCAC

Wind farm

Wind farm

EV station

AC Power gridAC Power grid

City

Energy storageSolarHVDC system

400 kV

5/15 kV 0.8/1.5 kV

63 kV

0.75/10 kV

5/15 kV0.8/1.5 kV1/10 kV100 kV

9 kVDC

DC

Thank you for your attention

• Verdicchio Andrea(1)(2)

• Ladoux Philippe(1)

• Caron Hervé(2)

• Sanchez Sebastien(1)

(1) Laplace (Laboratoire Plasma et Conversion d’Energie), University of Toulouse, INP.(2) SNCF RESEAU ( Société nationale des chemin de fer Français) , Paris, Plain ST Denis.

The research team