Overview of Microgrids, Problems and Solutionsmicrogrids.eu/micro2000/presentations/15.pdf ·...

“Distributed Generation, Grid and Micro Grid Problems”, Bilbao, 19th October 2004

Overview of Microgrids,Problems and Solutions

Nikos Hatziargyriou,[email protected]

National Technical University of Athens


Topics• Introduction• Definition• Technical, Economic and Environmental Benefits of

MicroGrids• Conceptual design of MicroGrids• Integration requirements and device-network

interfaces • Market and regulatory frameworks for MicroGrids• Modelling and simulation of MicroGrids• The MicroGrids Project• Conclusions


Introduction

• In the last 20 years power systems witnessed important changes:– Centralized paradigm versus more decentralized and

market driven approaches;– Legal and regulatory changes;

• Vertical and horizontal changes;• New tariff systems;

– Large technical advances (communications and computation);

– Larger environmental concerns;– New generation technologies


Photovoltaics

Fuel Cells

Microturbines

Reciprocating Engines

Distributed Generation Technologies

Advanced Turbines

Thermally Activated Technologies

Examples

Wind

“Distributed Generation, Grid and Micro Grid Problems”, Bilbao, 19th October 2004 -3Manuel SANCHEZ – European Commission – BETA SESSION 4b: Integration of RES+DG

Barcelona 12-15 May 2003

Yesterday Tomorrow: distributed/ on-site generation with fully integrated network management

Storage

Photovoltaicspower plant

Windpowerplant

House with domestic CHP

Powerqualitydevice

Storage

Central power station

House

FactoryCommercial

building

Local CHP plant

Storage

Storage

Powerqualitydevice

FlowControl

The vision…..

Transmission Network

Distribution Network


What are MICROGRIDS?

Interconnection of small, modular generation to low voltage distribution systems can form a new type of power system, the MicroGrid. MicroGrids can be operated connected to the main power network or autonomously, similar to power systems of physical islands, in a controlled, coordinated way .


Technical, economic and environmental benefits

• Energy efficiency • Minimisation of the overall energy consumption • Improved environmental impact • Improvement of energy system reliability and

resilience • Network benefits• Cost efficient electricity infrastructure replacement

strategies• Cost benefit assessment


Energy Efficiency - Combined Heat and Power

Prof. Dr. J. Schmid

Up to now:• Central power stations• Decentral heat production

In Future:• Decentral combined heat and power

⇒ 1/3 less consumption of fossil sources of energy100 % Oil / Gas

exchange of electrical energy

100 %powerstation

50 % electrical energy

50 % unusedwaste heat

50 % fossil fuel


EU Target:-20- 40 less in

in 2020!

Towards Kyoto or rather away from it?

Manuel Sanchez


.M.Amin – Balancing Market Priorities with Security Issues, IEEE Power&Energy, Vol. 2, Nr. 4, July/August 2004, data NERC’s disturbance analysis working group database)

Increasing frequency and size of US power outages 100 MW or more (1991-1995 vs. 1996-2000), affecting 50,000 or more consumers per event.


Improvement of Reliability Distribution of CMLs


.M.Amin – Balancing Market Priorities with Security Issues, IEEE Power&Energy, Vol. 2, Nr. 4, July/August 2004, data by EEI and graph by EPRI)

Utility Constructions: “Harvesting the farm far more rapidly than planting new seeds”

Since 1995 to the present, the amortization/depreciation rate exceeds utility construction expenditures


Capital Cost to Supply 2020 Capital Cost to Supply 2020 Electric Load GrowthElectric Load Growth

0

100

200

300

400

500

600

700

800

900

6% 22% 38% 54% 70%% DG of Total Generation

Euro

Bill

ions

for N

ew C

apac

ity

Inv. In New Cent. Gen. Inv. In new Dist. Gen. Inv. In T&D

(100% Central Scenario) (100% DG Scenario)

Ref: Conclusions Project DGRef: Conclusions Project DG--FER, 2004FER, 2004“Developing a Road Map for DG in Europe”“Developing a Road Map for DG in Europe”

Manuel Sanchez


Technical Challenges for Microgrids

• Relatively large imbalances between load and generation to be managed (significant load participation required, need for new technologies, review of the boundaries of microgrids)

• Specific network characteristics (strong interaction between active and reactive power, control and market implications)

• Small size (challenging management)• Use of different generation technologies (prime

movers) • Presence of power electronic interfaces • Protection and Safety


Market and Regulatory Challenges

• coordinated but decentralised energy trading and management • market mechanisms to ensure efficient, fair and secure supply

and demand balancing • development of price-based energy and ancillary services

arrangements for congestion management • secure and open access to the network and efficient allocation

of network costs • alternative ownership structures, energy service providers • new roles and responsibilities of supply company, distribution

company, and consumer/customer


MICROGRIDS Project

GREAT BRITAIN• UMIST• URENCO

PORTUGAL • EDP • INESC

SPAIN• LABEIN

NETHERLANDS• EMforce

USA• EPRI

GREECE• GERMANOS• ICCS/NTUA • PPC /NAMD&RESD

GERMANY• SMA• ISET

FRANCE • EDF• Ecole des Mines de Paris/ARMINES• CENERG

“Large Scale Integration of Micro-Generation to Low Voltage GridsContract : ENK5-CT-2002-00610

ARMINES

CENERG

ISET

ICCS / NTUAGERMANOS

EDF

SMA

UMISTURENCO

PPC/NAMD&RESD

LABEIN

14 PARTNERS, 7 COUNTRIES

INESC EDP

EPRI

http://microgrids.power.ece.ntua.gr


The MicroGrids ProjectR&D Objectives:

– Contribute to increase the share of renewables and to reduce GHG emissions;

– Study the operation of MicroGrids in normal and islanding conditions;

– Optimize the operation of local generation sources;– Develop and demonstrate control strategies to ensure efficient,

reliable and economic operation;– Simulate and demonstrate a MicroGrid in lab conditions;– Define protection and grounding schemes;– Define communication infrastructure and protocols;– Identify legal, administrative and regulatory barriers and propose

measures to eliminate them;


MICROGRIDS - 9 Workpackages

Investigation of Regulatory, Commercial, Economic and Environmental Issues

Development of Steady State and Dynamic Simulation Tools

Development of Local Micro Source ControllersDevelopment of Micro Grid Central Controller Development of Emergency Functions Investigation of Safety and Protection Investigation of Telecommunication Infrastructures

and Communication Protocols Development of Laboratory MicroGrids

Evaluation of the system performance on study case networks


MicroGrids Highlights• Islanding and interconnected operation philosophy• Control philosophies (hierarchical vs. distributed) • Energy management within and outside of the

distributed power system • Device and interface response and intelligence

requirements • Permissible expenditure and quantification of

reliability benefits• protection options for networks of variable

configurations• Steady State and Dynamic Analysis Tools


MicroGrids – Hierarchical Control

MicroGrid Central Controller (MGCC) promotes technical and economical operation, provides set points to LC and MC;

Interface with loads and micro sources and DMS;MC and LC Controllers: interfaces to control interruptible loads and micro sources (active and reactive generation levels).

MV LVDMSDMS

MGCCMGCC

DCAC

PV

MC

LC

MCAC

DC

LC

Storage

LC

~ CHPMC

Micro Turbine

MC

Fuel CellMCAC

DC

LCACDC

~

FlywheelMCAC

DC


Interconnected Operation

• MicroGrids can operate:– Normal Interconnected Mode :

• Connection with the main MV grid;• Supply, at least partially, the loads or injecting in the

MV grid;• In this case, the MGCC:

– Interfaces with MC, LC and DMS;– Perform studies (forecasting, economic scheduling,

DSM functions,…);


Islanding Operation

• MicroGrids can operate:– Island Mode :

• In case of failure of the MV grid;• Possible operation in an isolated mode as in physical

islands;• In this case, the MGCC:

– Changes the output control of generators from a dispatch power mode to a frequency mode;

– Primary control – MC and LC;– Secondary control – MGCC (storage devices, load

shedding,…);– Eventually, triggers a black start function.

Improvedreliability and

resilience


Integration requirements and device-network interfaces

• operation as the “good” and “model citizen”• seamless transition between interconnected/islanding

mode• resilience under changing conditions • operation fault level management and protection • recovery from disturbances and contribution to

network restoration • Safety, modularity, robustness, low losses, calibration

and self-tuning


Parallel operation of inverters

u

u

0 1-1 QQ N

-4%u

0

∆

f

f 0

0 1-1

-1%

PPN

f∆

Frequency droop Voltage droop

- Droops for synchronising inverters with frequency and voltage!- Frequency and voltage of the inverter is set according to active andand reactive power.


Voltage Regulation and Active Power control through droop

f

f0

0-1 1 PPN

∆f + 1%

-1 1

u

0 QQN

∆u + 4%u0

- Applied droop concept is based on inductive coupled voltage sources.

- In a LV-grid components are coupledresistive, thus voltage determinesthe active power distribution

- There are two effects of droops- direct (inductive coupling)- indirect (resistive coupling)

- The „indirect“ effect requires droops, which have the same sign for thefrequency as well as the voltage droop and therefore the stable operation point is „in phase“.

The compensation of lines was simu-lated and is recommendable. Over-compensation has to be avoided!


Development of Electronic Switch

-300

0

300

400 420 440 460 480 500 520 540 560 580 600

-100-80

-60-40

-200

2040

6080

100

400 420 440 460 480 500 520 540 560 580 600-1000

-800

-600

-400

-200

0

200

400

600

800

1000

v Mic

roG

rid [v

]

islandgrid connected

I Mic

roG

rid [A

]

time [ms]

I Grid

[A]


Two market policies :

1.Microgrid as a good citizen-maintains zero reactive power serving its own customers needs

2.The Microgrid buys and sells power to the grid

MGCC(MICRO GRID

CENTRAL CONTROLLER)

MC(LOCAL

CONTROLLER)Settings

Operational costfunction

Prices fromthe market

Prices offered to MGCC

Set-points foractive and reactive

power

Set-points for activeand reactive power

Suggested set-points

MicroGridMicroGrid Central ControllerCentral Controller


•• ““Good Citizen”Good Citizen”• MGCC tries to minimise the energy cost for the

Microgrid knowing :– Prices of the open market for Active and Reactive

power– Forecasted demand and renewable power production– Bids of the Microgrid producers.– Technical constraints

Policy 1Policy 1-- MicrogridMicrogridserving its own needsserving its own needs


Policy 2Policy 2--Buying and selling via Buying and selling via an Aggregatoran Aggregator

•• ““Ideal Citizen”Ideal Citizen”• The MGCC tries to maximise the value of the

µ-sources knowing :– The market prices for buying and selling energy

to the grid (Same prices for end-users of the Microgrid)

– Demand and renewable production forecasting– The offers of the µ-sources– The technical constraints for the interconnection

line and the µ-sources


3x250 A

Twisted Cable3x70mm2 Al XLPE +

54.6mm2 AAAC

80 Ω 80 Ω 80 Ω

80 Ω

Pole-to-pole distance = 30 mSingle residencial

consumer3Φ, Is=40 ASmax=15 kVAS0=5.7 kVA

3+N

2 Ω

Possible neutral bridgeto adjacent LV network

80 Ω

80 Ω

80 Ω

Single residencialconsumer3Φ, Is=40 ASmax=15 kVAS0=5.7 kVA

Group of 4 residences4 x 3Φ, Is=40 ASmax=55 kVAS0=25 kVA

Appartment building5 x 3Φ, Is=40 A8 x 1Φ, Is=40 ASmax=72 kVAS0=57 kVA

Underground line3x150 mm2 Al +

50 mm2 Cu XLPE cable


3x160 A

50 Ω

200 m

Workshop3Φ, Is=160 ASmax=70 kVAS0=70 kVA

3x160 A Overhead line4x50,35,16 mm2 Al conductors

3+N3+N

80 Ω

Pole-to-pole distance = 35 m

Overhead line4x120 mm2 Al XLPE

twisted cable

3Φ, Is=40 ASmax=20 kVAS0=11 kVA

1Φ, Is=40 APhase: a

Smax=8 kVAS0=4.4 kVA

4x1Φ, Is=40 APhase: abccSmax=25 kVAS0=13.8 kVA

3Φ, Is=63 ASmax=30 kVAS0=16.5 kVA

80 Ω

4x35 mm2 Alconductors

1Φ, Is=40 APhase: c


2x1Φ, Is=40 APhase: ab


80 Ω 80 Ω

80 Ω


80 Ω

80 Ω

4x1Φ, Is=40 APhase: abbcSmax=25 kVAS0=13.8 kVA

3x1Φ, Is=40 APhase: abc

Smax=20 kVAS0=11 kVA



80 Ω

80 Ω

0.4 kV

uk=4%, rk=1%, Dyn1120/0.4 kV, 50 Hz, 400 kVA

3+N3 Ω

20 kV

Off-load TC19-21 kV in 5 steps

Industrialload

Residentialload

Commercialload

LV network with multiple feeders


Study Case LV Feederwith DG sources

0.4 kV

uk=4%, rk=1%, Dyn1120/0.4 kV, 50 Hz, 400 kVA

3+N3 Ω

20 kV

Off-load TC19-21 kV in 5 steps

80 Ω

10 Ω

80 Ω

3x70mm2 Al XLPE +54.6mm2 AAACTwisted Cable

30 m

80 Ω 80 Ω 80 Ω

80 Ω


4x6 mm2 Cu

20 m4x25 mm2 Cu

3+N3+N+PE

3+N+PE

20 m

30 Ω

30 m

4x16 mm2 Cu

2 Ω

Possible neutral bridgeto adjacent LV network

80 Ω

80 Ω

20 m


Group of 4 residences4 x 3Φ, Is=40 ASmax=50 kVAS0=23 kVA

3+N+PE

1+N+PE

3+N+PE

3+N+PE

3+N+PE



3x50 mm2 Al +35mm2 Cu XLPE

Pole-to-pole distance = 35 m

Overhead line4x120 mm2 Al XLPE

twisted cable

80 Ω

Other lines

4x6 mm2 Cu

Flywheel storageRating to bedetermined

~~~

Microturbine3Φ, 30 kW

Photovoltaics1Φ, 3 kW

30 Ω

Photovoltaics1Φ, 4x2.5 kW

~Wind Turbine3Φ, 15 kW

Circuit Breakerinstead of fuses

80 Ω

30 m

4x16 mm2 Cu

Fuel Cell3Φ, 30 kW

10 Ω

~

Circuit BreakerPossible sectionalizing CB


• All three feeders taken into account

• Typical demand pattern and actual renewable power production time-series

• Amsterdam Power Exchange Prices.

• Bids from micro sources reflecting their production and installation cost

• Cost reduction of 6.6% for policies 1 and 2 without steady state security

• Steady state security increases cost by 6%.

Study CaseStudy Case of of MicrogridMicrogrid OperationOperation


Highlight: MGCC Simulation Tool


Policy1 Cost Reduction : 12.29 %

Policy 2 Cost reduction : 18.66%

Greater cost reduction when selling to the Grid

Load & Power exchange with the grid (residential feeder)

-30-20-10

0102030405060708090

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

kW

Pow er exchanged w ith the grid Load Pattern

Steady state security increases cost by 27% and 29% respectively.

Residential Feeder with DGs


Environmental BenefitsEnvironmental Benefits•• Average values for emissions of the main gridAverage values for emissions of the main grid

•• Data about emissions of the Data about emissions of the µµ--sourcessources..

27% reduction in CO2 emissions due to policy1

Maximum reduction in CO2 emissions 548kgr/day- 22.11% higher cost


Duration of outages in some EU countries during 2002 [Minutes/year]

0

100

200

300

400

500

600

Finlan

dFran

ce UK

Italy

Irelan

dNeth

erlan

dsNorw

ayPort

ugal

Spain

Min

utes

Source: Dolf De Loo. KEMA T&D Consulting

Annual duration of outage in some EU countries.

99.9%

99.99%


Highlight - Permissible expenditure to enable islanding

Customer Sector: Residential Commercial

Annual benefit = 1.4 £/kWpk 15 £/kWpk

Net present value = 15 £/kWpk 160 £/kWpk

Peak demand = 2 kW 1000 kW

Perm. expenditure = £30 £160,000

MicroGrid (2,000kW) £30,000 £320,000


Effects on Losses

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

KW

Losses with DG Losses without DG

Active power losses with and without DG


MICROGRIDS Highlight 3: Reliability Assessment of LV Network

System Maximum Load Demand: 188 kWCapacity of System Infeed: 210 kW (100%)Installed Capacity of Wind Generation: 15 kWInstalled Capacity of PVs: 4*2,5+1*3 = 13 kWInstalled Capacity of Fuel Cells: 30 kW Installed Capacity of Microturbines: 30 kW


Reliability AssessmentFLOL (ev/yr) LOLE (hrs/yr) LOEE (kWh/yr)

Infeed Capacity 100%

(no microsources) 2,130 23,93 2279,03

Infeed Capacity 80%

(no microsources) 58,14 124,91 3101,52

Infeed Capacity 80%(with Wind + PV) 14,02 41,67 2039,41

Infeed Capacity 80%(all microsources) 2,28 15,70 716,36


Reliability Assessment – continuedFLOL (ev/yr) LOLE (hrs/yr) LOEE (kWh/yr)

Infeed Capacity 90%

(no microsources) 8,52 31,08 2313,77

Infeed Capacity 90%, system load 207 kW (+10%)

(no microsources) 44,10 92,75 3073,84

Infeed Capacity 90%, load 207 kW(with Wind + PV) 11,35 36,69 2232,54

Infeed Capacity 90%, load 207 kW(all microsources) 2,305 16,55 911,68


Modelling and simulation of MicroGrids

• modelling of generator technologies (micro generators, biomass fuelled generation, fuel cells, PV, wind turbines), storage, and interfaces

• load modelling and demand side management • unbalanced deterministic and probabilistic load flow and fault

calculators • unbalanced transient stability models • stability and electrical protection • simulation of steady state and dynamic operation • simulation of interactions between Microgrids


Main Characteristics of LV Distribution Networks

Radial or meshed network developmentR comparable or even greater than X ( R/X ~ 5)Unbalanced excitation (loading or generation)Unbalanced network conditions

Single phase network sectionsMutual coupling between network components

Various earthing arrangements TN (TN-S, TN-C)TTIT


Main Characteristics of Simulation Tool

• Phasor approach adopted for network and sources to increase simulation efficiency.

• Natural phase quantities (a-b-c) are used.• Microsources represented as EMFs behind

impedance, neglecting “stator transients”.• Lines with any X/R ratio can be handled.• Radial and non-radial network topologies. All basic

neutral earthing schemes can be represented (TN, TT, IT).


Main Characteristics of Simulation Tool/2

• Unbalanced conditions (network, sources, loads) can bemodelled and simulated.

• Dynamic simulation of grid-connected and autonomousmode of operation.

• Microsources integrated in the code with their respective electronic interfaces.

• Simulation tool based on Matlab and Simulink. Matlab for the core network solver, initialization and post-processing, Simulink for prime movers, controls and numerical integration.


Simulated Microgrid

IG

0 KVA

p.f. 0.852,7 KVA

0 KVA

8 KVAp.f. 0.85

4,8 KVA6,4 KVA

2,7 KVAp.f. 0.85

2 KVA1 KVA

p.f. 0.85

1,6 KVA

4 KVA2,4 KVA 3,2 KVA

p.f. 0.854 KVA

1,6 KVA

G

A B

CD

E

Transformer400KVA6%

Distribution Sys.

20 KV 0,4 KVPhotovoltaics4KW

Photovoltaics3KW

Wind TurbineIG 3ph 5,5KW

BatteriesSmax 35 KVA p.f 0.85

InverterSmax 25 KVA Inverter

p.f 0.85 Batteries

Lines

4 AL 4 x 120mm2 35m

2 Cu 4 x 6mm2 20m1 AL 4 x 120mm2 35m

1 3 4 7 8 11 12 14 15

1713105

6

1692

3 AL 4 x 120mm2 35m

5 AL 3 x 70 + 54,6mm2 105m6 AL 3 x 50 + Cu 54,6mm2 30m7 AL 4 x 120mm2 35m8 AL 4 x 120mm2 35m

10 Cu 4 x 5mm2 10m9 Cu 4 x 25mm2 20m

11 AL 4 x 120mm2 35m12 AL 4 x 120mm2 35m13 Cu 3 x 6mm2 20m14 AL 4 x 120mm2 35m15 AL 4 x 120mm2 35m16 Cu 4 x 16mm2 30m17 Cu 4 x 10mm2 10m18 Cu 4 x 4mm2 10m

18


Study Case ETwo battery invs + two PVs + one WT - Isolation + wind

fluctuations

P inverter A,B

Q inverter A,B

Frequency



fluctuations

P,Q per phase WT

Rotor speed WT



fluctuations

P,Q per phase inverter A I per phase inverter A


Further Needs Identified– Μore sophisticated control techniques for local Distributed

Resource and load controllers to implement – Study of integration of several Microgrids into operation

and development of the power system. Interaction with DMS.

– Need for standardization and benchmarking. – Field trials to test control strategies on actual Μicrogrids

– Need for quantification of Microgrids effects on Power sysetm operation and planning

– Need for cooperation and learning from alternative, complementary approaches, under development in US, Canada and Japan


The Kythnos Microgrid - CRES


Pilot plant on Kythnos – Testing Control

•Supply of 12 buildings (EC projects MORE and PV-Mode)

PV-Generator PV-Generator

PV-Generator

Battery

=~

=~

=~

PV

AC-Grid: 3~ 400 V

AC Grid: 3~ 400 V

Battery

=~

=~

Diesel

=~

PV

=~

PV-ModeMORE

=~

=~ =

~

=~


The Kythnos Microgrid


Holiday-Parc Bronsbergen, Zutphen, The Netherlands - CONTINUON

More then 200 cottages. A great number equipped with PV-generators (315 kW), coupled to the grid by means of inverters


EDPEDP Study CaseStudy Case

LSVAV 3x185+95+16 16 m

LSVAV 3x95+50+16 23 m

Fuse 160 A

6,9 kVA

(139 m) LXS 4x70+16

25 m

10,35 kVA + 20,7 kVA

24 m

2x3,45 kVA

3x3,45 kVA

3 m

3x3,45 kVA

25 m

XS

4x6

22 m

LXS

4x2

5+16

2x3,45 kVA

22 m

3,45 kVA

5 m

8 m

2x3,45 kVA 2x3,45 kVA

4 m 5 m

15 m

2x3,45 kVA + 20,7 kVA

29 m

10,35 kVA

2x3,45 kVA

3 m

27

m

LXS

4x2

5+16

2 m

3 m

4

m

2x3,45 kVA

3,45 kVA

3,45 kVA

XS 4x69 m

2x3,45 kVA

19 m

2x6,

9 kV

A +

20,7

kVA

17 m

LXS

4x7

0+16

34

m

3,45 kVA

20,7 kVALSVAV 4x3526 m

6 m

3,45 kVA + 20,7 kVA

6 m

7

m

15 m

3,45 kVA + 10,35 kVA

LXS 4x25

24 m

10,35 kVA

3,45 kVA + 10,35 kVA

2 m

3 m 12 m

(43 m) LXS 4x70+16

30 m 1 m

24 m

(161

m)

LXS

4x7

0+16

10,3

5 kV

A +

6,9

kVA

22 m

10,35 kVA

22 m

32

m

38 m

20,7 kVA

23 m

3,45 kVA2x3,45 kVA

Sec

cion

ador

(55 m) LXS 4x70+16

22 m

3x6,9 kVA

LX

S 4x

25+1

6 12

m

6,9 kVA + 3,45 kVA

33 m

20,7 kVA 30 m

21 m

(51

m)

LXS

4x25

+16

(247 m) LXS 4x70+16

LXS 4x25+16 (126 m)

41 m

49 m 33 m

10,35 kVA

XS

2x6

15 m

10,35 kVA

41,5 kVA

LXS

4x25

+16

3 m

31 m 23 m

10,35 kVA

XS 4

x6

33m

6,9 kVA

40 m

10,35 kVA

10,35 kVA

10,35 kVA

LXS

4x25

+16

30 m

30 m

(188 m) LXS 4x50+16

16 m 33 m 45 m 34 m

29 m

31

m

20,7 kVA

10,35 kVA

XS 4x6 7 m

2x3,45 kVA

3,45

kV

A +

10,3

5 kV

A

LSV

AV

4x35

12 m

S = 200 kVA U = 10 kV

LSVAV 4x95

S = 160 kVA U = 10 kV

3,45

kV

A +

10,3

5 kV

A

G ~

80 kW

VV 4

x6

VV 2x6

VV 2x6VV 2x6

VV 4x6 VV 4x6

VV 4

x6

VV

4x6

V

V 4x

6

VV

4x6

VV 4

x6

VV

4x6

VV 4

x6

VV 4x6

Dyn

Dyn

VV

4x6

Micro-source Micro-turbine


Microturbine – Testing Transfer


Conclusions

• Microgrids: A new paradigm for future power systems

• Distinct advantages regarding efficiency, reliability, network support, environment, economics

• Challenging technical and regulatory issues• Needs for benefits quantification

http://microgrids.power.ece.ntua.gr

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