IEEE Electrification Magazine - September 2014 - 54

Traction
Substation
Railway
Power System
(Controlled by
RSO)

Traction
Substation

Traction
Substation
ESS

Railway
System
Operator

Traction
Substation

RSO

RDG

Controls the
Railways Power
Flows ( ) and
the Traffic Flow
(
)

Figure 5. The control of future railway ESGs.

auxiliary loads onboard (e.g., the cooling system of the
traction equipment, air conditioning, lighting, and entertainment equipment). Some of these loads can be managed in
smart way, modulating the power consumption according to
the needs of the system (and the train itself).

Smart Operation of the RPS
RPSs normally have a limited set of controllable devices,
including the switching devices (breakers, disconnectors,
etc.), on-load tap changers of the transformers, and converters used to connect the RPS to the T&D grid (in 16.6-Hz
systems and similar). Because of this limited controllability, the conception of AMD strategies has been, so far, the
most common approach in RESG research.
However, this tendency is very likely to change in the
future thanks to the advances in power electronics that

make it possible to reach higher voltages, transferring more
power more efficiently and more affordably. With these
technologies, a smart control of the power flows within the
RPS would be possible.
Figure 7 compares two different concepts for controlling the power flows. In solution A [Figure 7(a)], the power
flow is controlled at every coupling point to the supplying
grids (in the TSS) by the controlling devices labeled PFR.
Alternatively, in solution B [Figure 7(b)], the controlling
devices (PFE in the figure) set the power flows between
adjacent sections, which indirectly control the power flow
supplied by each TSS. (The ESS and RDG are controlled in
the same way as in solution A.)
Regardless of which solution is adopted, controlling the
power flows within the RPS can significantly help to
achieve the purposes of the RESGs, such as minimizing the

the merLIN project

T

54

he MERLIN project (http://www.

Network Rail, and Trafikverket), supported

leading to a cost-effective, intelligent

merlin-rail.eu) is an important initiative

by consulting companies (D´Appolonia),

management of energy and resources through:

in the European Union (EU) context that

universities (Newcastle University and

comes up as a response to the fifth call

RWTH-Aachen University), and research

issued by the European Commission as

centers and professional associations [the

part of Seven Framework Programme.

Association of European Railway Industries

The partnership gathered to achieve the

(UNIFE), the Union Internationale des

railway operations and procedures on

MERLIN objectives is composed of 20

Chemins de Fer (UIC), and the Spanish

energy demand

partners from eight EU member states

Railways Foundation (FFE)].

■

improved design of railway distribution
networks and electrical systems and
their interfaces

■

■

better understanding of the influence of

identification of energy usage optimizing
technologies

(Czech Republic, Ger many, France,

As mentioned on its official site, the aim

Belgium, Italy, Spain, United Kingdom,

of the MERLIN project is to investigate and

■

improved traction energy supply

and Sweden), comprising different

demonstrate the viability of an integrated

■

understanding of the cross-dependencies

European railway systems integrators and

management system to achieve a more

equipment suppliers (ALSTOM, AnsaldoSTS,

sustainable and optimized energy usage in

AnsaldoBreda, MerMec, SIEMENS, CAF, and

European electric mainline railway systems

Oltis Group), along with railway operators

and to provide an integrated and optimized

(RENFE), infrastructure managers (ADIF, RFF,

approach to support operational decisions,

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

between technological solutions
■

improving cost-effectiveness of the
overall railway system

■

contribution to European standardization
(TecRec).
http://www http://www.merlin-rail.eu
Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2014
