Microgrids and Active Distribution Networks

321 Pages·2009·3.12 MB·English

IET RENEWABLEENERGYSERIES 6
Microgrids and Active
Distribution Networks

Microgrids and Active
Distribution Networks
S. Chowdhury, S.P. Chowdhury and P. Crossley
The Institution ofEngineering and Technology
PublishedbyTheInstitutionofEngineeringandTechnology,London,UnitedKingdom
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Firstpublished2009
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Contents
Foreword xiv
Preface xv
Acknowledgements xvii
Listofabbreviations xviii
1 Distributed generation and Microgrid concept 1
1.1 Distributed generation 1
1.2 Why integration of distributed generation? 2
1.3 Active distribution network 2
1.4 Concept of Microgrid 3
1.5 A typical Microgrid configuration 4
1.6 Interconnection of Microgrids 8
1.7 Technical and economical advantages of Microgrid 8
1.8 Challenges and disadvantages of Microgrid development 10
1.9 Management and operationalissues of aMicrogrid 11
1.10 Dynamic interactions of Microgrid with main grid 11
1.11 Conclusion 12
2 Distributed energy resources 15
2.1 Introduction 15
2.2 Combined heat and power (CHP) systems 15
2.2.1 Micro-CHPsystems 16
2.3 Wind energyconversion systems (WECS) 26
2.3.1 Windturbineoperatingsystems 27
2.4 Solar photovoltaic (PV) systems 29
2.4.1 TypesofPVcell 30
2.5 Small-scale hydroelectric power generation 32
2.6 Other renewable energy sources 32
2.7 Storage devices 33
2.8 Conclusion 33
3 Impacts of Microgrid 35
3.1 Introduction 35
3.2 Impact on heat utilisation 36
3.2.1 Supplyofthermalenergy 36
3.2.2 Absorptionchillers 38
viii Microgrids and active distribution networks
3.2.3 Desiccantdehumidifiers 38
3.2.4 Thermalenergystorage 39
3.3 Impact on process optimisation 39
3.3.1 HVACsystemoptimisation 39
3.3.2 Powerquality 41
3.3.3 Powercostconsiderations 42
3.3.4 Costsoftransmissioncongestion 42
3.3.5 BasicMicrogridcostconsiderations 42
3.4 Impact on market 43
3.4.1 Possibilitiesintheelectricitymarket 43
3.4.2 Gasmarketanditsdifficulties 44
3.4.3 Necessarymarketreforms 45
3.5 Impact on environment 46
3.5.1 Minimisationofpollutantdeposition 46
3.6 Impact on distribution system 47
3.6.1 Ancillaryservices 48
3.6.2 DistributionsystemissuesofMicrogrid 51
3.7 Impact on communication standardsand protocols 52
3.7.1 Protocols,communicationproceduresand 52
gateways
3.7.2 Alternativecommunications 53
3.8 Conclusion 54
4 Microgrid andactivedistribution networkmanagement system 57
4.1 Introduction 57
4.2 Network management needs of Microgrid 57
4.2.1 Microsourcegenerationcontrol 58
4.2.2 Domesticprocesscontrol 58
4.2.3 Energystorage 59
4.2.4 Regulationandloadshifting 59
4.2.5 Ancillaryservices 60
4.3 Microsource controller 61
4.3.1 Controlfunctionsformicrosourcecontroller 61
4.4 Central controller 65
4.4.1 Energymanagermodule(EMM) 65
4.4.2 Protectionco-ordinationmodule(PCM) 68
4.4.3 Informationneededforcentralcontroller 71
operation
4.4.4 Controlstrategiesforcentralcontrollerdesign 74
4.5 Conclusion 76
5 Protection issues for Microgrids 77
5.1 Introduction 77
5.2 Islanding: separation from utility 79
5.2.1 Differentislandingscenarios 80
5.3 Major protection issues of stand-aloneMicrogrid 84
5.3.1 Microgriddistributionsystemprotection 84
5.3.2 Protectionofmicrosources 88
Contents ix
5.3.3 NECrequirementsfordistributiontransformer 90
protection
5.3.4 Neutralgroundingrequirements 91
5.4 Conclusion 94
6 Power electronic interfaces 97
6.1 Introduction 97
6.2 Background 97
6.2.1 Standardcomputerarchitecture 98
6.2.2 Verylargescaleintegration(VLSI) 98
6.3 Power converter trends 99
6.3.1 Customdesignandmanufacturing 99
6.3.2 Powermoduleintegrationandcomponent 99
packaging
6.3.3 Powerelectronicbuildingblocks(PEBB) 100
6.3.4 Packagingframeworkdesign 100
6.4 Bricks-Buses-Software (BBS) framework 100
6.4.1 Bricksasmodularcomponents 101
6.4.2 Busesasconnectivelinks 103
6.4.3 High-levelsoftwaredesignenvironment 104
6.5 BBS framework issues 105
6.5.1 Modularity 105
6.5.2 Aspectratio 105
6.5.3 Parasiticinductance 106
6.5.4 Crosscouplingandloading 106
6.6 Conclusion 106
7 SCADA and active distribution networks 109
7.1 Introduction 109
7.2 Existing DNO SCADA systems 109
7.3 Control of DNO SCADA systems 110
7.3.1 CentralisedSCADAsystems 110
7.3.2 DistributedSCADAsystems 111
7.4 SCADA in Microgrids 111
7.5 Human–machine interface (HMI) 112
7.6 Hardware components 112
7.6.1 Remoteterminalunit(RTU) 113
7.6.2 Programmablelogiccontroller(PLC) 114
7.6.3 MasterstationandHMIcomputers 115
7.6.4 SCADAcommunicationinfrastructure 115
7.7 Communication trends in SCADA 116
7.8 Distributed control system (DCS) 117
7.9 Sub-station communicationstandardisation 118
7.10 SCADA communication and control architecture 119
7.11 Communication devices 119
7.12 Observations on SCADA and communication 120
7.13 Conclusion 123