A new step towards smart gridsSmart grids are one of the technological responses to the European Union’s ‘3x20’ goal, as part of its 2020 climate and energy package: 20% of energy from renewables, a 20% improvement in energy savings and a 20% cut in greenhouse gas emissions. The effective introduction of intermittent-type renewable energy generation (wind and photovoltaic power), along with new uses for electri-city (such as heat pumps and electric vehicles) within the power system, require the design of ‘smart’ equipment, particularly based on new information and communica-tion technologies. A major challenge here involves inte-grating these various items of equipment, stemming from different but converging ‘technological worlds’ (such as communicating metering systems, sensors and converters) within an exacting industrial context in terms of quality, safety, security and cost. Grid laboratories open up various possibilities for experimenting with smart grid solutions, to prepare for distribution network upgrades and to develop new proposals for energy efficiency services.

Network laboratories dedicated to smart grids UNLIKE NET WORKS IN THE REAL WORLD, EXPERIMENTAL GRIDS CAN BE EXPOSED TO MULTIPLE DISTURBANCES

Exceptionally ‘smart’ European grid laboratoriesThe evolution of electric systems is not limitated to French concerns. Like EDF with its Concept Grid, laboratories such as RSE (Italy), Kema (The Netherlands), PowerLabDK (two DTU sites in Denmark) and Ustrat – the University of Strathclyde (GB), have created experimental grids in anticipation of future upgrades. The European DERLab (Distributed Energy Resources Laboratories) association also brings a large number of initiatives together in this field.

A smart grid is an ‘intelligent’ electricity distribution network that uses data-processing technologies to optimise generation, distribution and consumption. A grid laboratory is a test platform structured around a system that is small in size but that can be configured to represent an actual network. Designed for testing smart grid solutions as part of a ‘systemic’ approach, before they are incorporated into the actual network, the laboratory provides the missing link between:• Unit-tests on individual pieces of equipment without viewing

interactions with the system,• demonstrators in the

f ie ld, which doesn’t allow to test multiple disturbances affecting a power system.

A grid laboratory provides the option to carry out complex test campaigns that would not be feasible on an actual network. It also allows us to study the incorporation of certain systems under actual conditions, while keeping control over the constraints to which they need to be subjected.Jean-François Faugeras, Deputy Executive Vice President for the grids programme at EDF R&D

EDF R&D DECEMBER 2012 innovation.edf.com

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Grid laboratories in Europe

EDF R&D has bu i l t i t s own gr id laboratory, Concept Grid, on 3 hectares of land at its Renardières site (Seine-et-Marne), providing a unique resource for investigation and integration.

Unprecedented equipment in EuropeCo m p a re d to o t h e r sma r t g r i d laboratories, EDF’s Concept Grid has unprecedented characteristics:• Configurable 20 kV and low-voltage

(LV) electrical networks• A powerful and flexible electronic

source, capable of in jec t ing or absorbing computer- contro l led disturbances, connected to a real-time simulator.

• Different types of 20 kV neutral point arrangements (including electronic).

• An instrumentation and control system compliant with new standards (IEC 61-850), along with dedicated I&C and measurement communication systems.

• D irec t connec t ion to spec ia l i s t laboratories (photovoltaics, heat pumps, batteries, smart houses) and to a group of small dwellings fitted with micro-wind turbines, photovoltaic panels, storage systems, smart meters and charging terminals.

A representative gridThe experimental grid’s nerve centre is located on a plateau and consists of a dedicated control station for the laboratory, a building to accommodate the main pieces of electrical equipment and an area of test dwellings. A great deal of attention has been paid to the representativeness of the grid: Concept Grid has medium-voltage (20 kV) underground and overhead cables , three publ ic d is t r ibut ion substat ions and low-voltage (LV ) systems. To artificially extend the 20 kV system, the 120 km of overhead and

underground network are represented by means of a combination of resistors, inductors and capacitors (RLC cells) incorporated in the 20 kV circuits. Sources and loads representative of new types of usage are installed in dif ferent areas of the site and connec ted to Concept Gr id. The incorporation of renewable energy sources is characterised by a large number of photovoltaic panels and two micro-wind turbines and power usage is represented by five test dwellings, fitted with domestic equipment such as heat pumps or charging terminals for electric vehicles. Concept Grid also supplies power to test platforms and an office building. The assembly is completed by the LV power source and a rotating machine that can operate as either a source or a load. A large number of d i f ferent dis turbances can be generated.

FROM CONCEPT TO GRID

Miniature grids forlarge-scale testingGRID LABORATORIES MUST BE REPRESENTATIVE OF REAL ELECTRIC SYSTEMS

THE RECIPE

Obtain your power sources:

- 1 x 63 kV/20 kV 20 MVA

power transformer.

- 20 kVA of photovoltaic

panels.

- 2 x micro-wind turbines

(10 kVA).

- 1 x 120 kVA LV amplifier

(in generator).

Add some loads:

- 1 x 500 kVA office building.

- 5 x test houses fitted

with domestic equipment

(50 kVA).

- Heat pumps up to 50 kVA.

- Charging terminals for

electric vehicles up to

100 kVA.

- 1 x 60 kVA LV amplifier

(in consumer).

Combine all of the above

with:

- 3 km of HTA (20 kV)

underground and overhead

cables.

- 120 km of 20 kV network

simulated by RLC cells.

- 7 km of LV circuits.

- 2 x 400 kVA distribution

substations.

- 3 x 20 kV neutral point

arrangements, including

1 x completely innovative

electronic neutral.

- 1 x 50 kVA rotating

machine.

Chef’s tip:

Serve your grid laboratory

with plenty of skills and

expertise in the electrical

and IT fields.

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Concept Grid: coil for an active neutral point arrangement

Extensive grid disturbance monitoringThe experimental network operates in conjunction with a fibre optic and radio telecommunications system, which incorporates smart grid-type functions and enables the experiments to be controlled and monitored. An instrumentation and control system manages and monitors the grid from the control station. Any kind of disruptive situation likely to be encountered on the actual grid can be created at will, enabling the behaviour of the equipment (such as the I&C or the metering equipment) to be studied in these kinds of scenarios. Systematic failure surveys, particularly involving faults to earth, can be conducted to measure their consequences in terms of currents and overvoltages. The grid operators can reproduce a real-life fault and study potential corrective measures. The LV grid can be supplied either by the 20 kV network via two substations, or by the controllable electronic power source. Numerous switching operations can be performed to modify the structure of the grid or change its length and, therefore, its short-circuit power. The

controlled electronic source can be used for assessing the behaviour of equipment installed in the houses or on the test platforms in different upset conditions, involving voltage disturbances, variable frequency and harmonics. The impacts of different types of LV generation or consumption can also be assessed, particularly emitted disturbances in various different configurations applicable to an actual grid. The LV electronic source can be connected to a simulator to simulate a grid supplying actual loads or a load supplied by an actual grid. The 20 kV network incorporates three neutral point arrangements, one of which is electronic; these al low the gr id to cont inue operating, even when there is a fault, by reducing the earth fault current. Specific tests, focusing on smart grid functions or data-processing security, can also be performed. Simulation tools can be validated by comparing the results from a simulation with the actual behaviour measured. The laboratory is upgradeable: a large-capacity storage solution is currently being examined and plans are under way to install a direct current multi-terminal connection.

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DID YOU KNOW ?

In 2030, the French distribution network could have the following characteristics:

- More than 4,000 wind power plants.

- 2 million photovoltaic installations.

- 600,000 km of medium-voltage (MV) network.

- 675,000 km of low-voltage (LV) network.

- More than 2,200 primary substations.

- 30 control agencies.

- More than 60,000 remote-controlled devices.

- 8 million electric vehicles.

- 33 million LV customers and 100,000 MV customers. Source: ERDF

OutlookEDF’s Concept Grid is a reference laboratory for studies and experiments relating to smart grids systems. It supplements the smart grid test resources already available in Europe.

An upgradeable toolThanks to its original characteristics (representativeness, modularity and operational flexibility), Concept Grid enables us to conduc t fu l l - sca le investigations that yield directly usable results. It also provides a meeting ground for various players working in different fields, such as universities, l abora to r i e s , s y s tem opera to r s , manufacturers and utility companies. From the design phase onwards, all possible measures have been taken to make Concept Grid upgradeable. Tests can be conducted for very specific needs or as part of wider partnerships. The Concept Grid team can examine the feasibility of possible experiments and suggest the most appropriate answer. Each experiment requires specific organisation and equipment.

ExperimentsConcept Grid is used to conduct a large number of experiments to address a wide variety of issues, such as fault surveys on the underground medium-voltage loop to test the automatic loop reconfiguration systems. Applying this principle on an actual network would significantly reduce the duration of customer power cuts in the event of damage, thus improving the continuity of the electr icity supply. Another experiment might involve investigating the impact of rapid electric vehicle charging on the rest of the grid. Concept Grid will enable us to study this issue and examine possible courses of action for improvement. Management systems with this type of load can also be developed and tested before they are brought into general use. These types of experiments, with quite different scopes, offer an insight into just some of the possible uses for Concept Grid.

Pierre Migaud, expert Michel Oddi, senior researcher Benoît Puluhen, Concept Grid project manager, EDF R&D

List of termsPower amplifier: device consisting of electronic components

capable of generating (source) or absorbing

(load) an electrical current whose form and

characteristics (range, voltage, frequency,

harmonics) are electronically controlled.

Instrumentation and control: set

of low-voltage equipment for protecting,

monitoring and controlling an electrical

system (substation or grid).

Fault: accidental contact between a

conductor and the earth and/or between

conductors.

Distribution substation: point

through which the electric power passes

between the 20 kV network and the low-

voltage (LV) network. It includes a 20 kV /

LV transformer, managed by switching and

protection devices.

Protection device: equipment

designed to detect a fault and initiate the

necessary actions to eliminate it.

Neutral point arrangement: method for earthing the neutral point of

a three-phase system. The four possible

options are: direct earthing, insulation, low

impedance or compensation (Petersen coil).

System disturbance: situation in

which a grid’s electrical characteristics

diverge from its normal operating conditions

(voltage level, frequency, harmonics).

Smart grid: electrical power network

that uses information exchange and control

technologies, a distributed data-processing

system, and the associated sensors and

actuators, to incorporate the behaviour

and actions of network users and other

stakeholders, and to provide a sustainable,

economical and safe electricity supply in an

effective way (International Electrotechnical

Commission definition).

EDF22-30 avenue de Wagram 75382 Paris Cedex 08 FRANCE

French limited company with a capital of €924,433,331Paris Trade and Companies Register no. 552 081 317

www.edf.fr

Please do not print this document unless you need to.Publication EDF R&D - 1 av Général de Gaulle 92141 Clamart CedexPublishing Director: Stéphane AndrieuxEditorial secretary: Florence Metge-LaymajouxThe author, and not EDF, is solely responsible for the content of this publication.

© 2015 EDFReproduction prohibited without prior authorisation from the author. Photo credits: Benoît Puluhen, EDF R&D

The EDF Group is ISO 14001 certified

> pour en savoir plusDistributed Energy Resources Research Infrastructure (DERRI): http://www.der-ri.net

International Electrotechnical Commission (IEC): http://www.iec.ch

Main grid laboratories in Europe• Concept Grid: edf.fr

• DTU Electric Lab (in Lyngby) and Syslab (in Risoe): http://www.powerlab.dk

• Power Networks Demonstration Centre: http://www.strath.ac.uk

• Laboratorio Test Facility di Generazione Distribuita in bassa tensione:

http://www.rse-web.it/laboratori/laboratorio/32

• Flex Power Grid Laboratory: http://www.flexpowergridlab.com and http://www.kema.com

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Contact:

communication-rd@edf.frhttp://innovation.edf.com

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