CLC TR 50609-2014 Technical Guidelines for Radial HVDC Networks.pdf

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1、BSI Standards PublicationTechnical Guidelines for Radial HVDC NetworksPD CLC/TR 50609:2014National forewordThis Published Document is the UK implementation of CLC/TR 50609:2014.The UK participation in its preparation was entrusted to TechnicalCommittee GEL/8, Systems Aspects for Electrical Energy Su

2、pply.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its correct application. The British Standards Institution 2014.Published by BSI Sta

3、ndards Limited 2014ISBN 978 0 580 83555 1ICS 29.240.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of theStandards Policy and Strategy Committee on 31 March 2014.Amendments/corrigenda issued since publicatio

4、nDate Text affectedPUBLISHED DOCUMENTPD CLC/TR 50609:2014TECHNICAL REPORT CLC/TR 50609 RAPPORT TECHNIQUE TECHNISCHER BERICHT February 2014 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung

5、CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels 2014 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. CLC/TR 50609:2014 E ICS 29.240.01 English version Technical Guidelines for Radial HVDC Networks Directives techni

6、ques pour les rseaux HVDC radiaux Technischer Leitfaden fr radiale HG-Netze This Technical Report was approved by CENELEC on 2013-12-09. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former

7、Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CLC/TR 50609:2014CLC/TR 50609:2014 2

8、Contents Page Foreword 7 0 Introduction 8 0.1 The European HVDC Grid Study Group . 8 0.2 Technology . 9 0.2.1 Converters 9 0.2.2 DC Circuit . 9 0.2.3 Technological Focus of the European HVDC Grid Study Group 10 1 Scope . 12 2 Terminology and abbreviations 12 2.1 General 12 2.2 Terminology and abbrev

9、iations for HVDC Grid Systems used in this report 12 2.3 Proposed Terminology by the Study Group 13 3 Typical Applications of HVDC Grids 14 3.1 The Development of HVDC Grid Systems 14 3.2 Planning Criteria for Topologies . 15 3.2.1 General 15 3.2.2 Power Transfer Requirements 16 3.2.3 Reliability 17

10、 3.2.4 Losses . 19 3.2.5 Future Expansions. 21 3.3 Technical Requirements 21 3.3.1 General 21 3.3.2 Converter Functionality 22 PD CLC/TR 50609:20143 CLC/TR 50609:2014 3.3.3 Start/stop Behaviour of Individual Converter Stations 23 3.3.4 Network Behaviour during Faults 24 3.3.5 DC-AC Interface Require

11、ments 25 3.3.6 The Role of Communication . 26 3.4 Typical Applications Relevant Topologies . 27 3.4.1 General 27 3.4.2 Radial Topology . 27 3.4.3 Meshed Topology 29 3.4.4 HVDC Grid Systems Connecting Offshore Wind Power Plants 29 3.4.5 Connection of a wind power plant to an existing HVDC VSC link 30

12、 4 Principles of DC Load Flow. 31 4.1 General 31 4.2 Structure of Load Flow Controls 31 4.2.1 General 31 4.2.2 Converter Station Controller 31 4.2.3 HVDC Grid Controller 32 4.3 Converter Station Control Functions . 34 4.3.1 General 34 4.3.2 DC Voltage (UDC) Stations . 34 4.3.3 Active Power (PDC) and

13、 Frequency (f) Controlling Stations 34 4.4 Paralleling Transmission Systems . 35 4.4.1 General 35 4.4.2 Paralleling on AC and DC side . 35 4.4.3 Paralleling on the AC side 35 4.4.4 Steady-State Loadflow in Hybrid AC/DC Networks 36 PD CLC/TR 50609:2014CLC/TR 50609:2014 4 4.5 Load Flow Control 38 4.5.

14、1 DC Voltage Operating Range 38 4.5.2 Static and Dynamic System Stability . 39 4.5.3 Step response 39 4.6 HVDC Grid Control Concepts 40 4.6.1 General 40 4.6.2 Voltage-Power Droop Together with Dead Band 45 4.6.3 Voltage-Current Droop 48 4.6.4 Voltage-Power Droop Control of the HVDC Grid Voltage . 54

15、 4.7 Benchmark Simulations of Control Concepts . 57 4.7.1 Case Study . 57 4.7.2 Results 58 4.7.3 Conclusions . 60 4.7.4 Interoperability . 61 5 Short-Circuit Currents and Earthing 61 5.1 General 61 5.2 Calculation of Short-Circuit Currents in HVDC Grid Systems . 61 5.3 Network Topologies and their I

16、nfluence on Short-Circuit Currents . 63 5.3.1 Influence of DC Network Structure 63 5.3.2 Influence of Line Discharge 66 5.3.3 Influence of Capacitors . 67 5.3.4 Contribution of Converter Stations 69 5.3.5 Methods of Earthing 72 5.4 Secondary Conditions for Calculating the Maximum/Minimum Short-Circu

17、it Current . 73 5.5 Calculation of the Total Short-Circuit Current (Super Position Method) 74 PD CLC/TR 50609:20145 CLC/TR 50609:2014 5.6 Reduction of Short-Circuit Currents 75 6 Principles of HVDC Grid Protection . 76 6.1 General 76 6.2 HVDC Grid System . 77 6.3 AC/DC Converter 78 6.3.1 General 78

18、6.3.2 DC System 79 6.3.3 HVDC Switchyard. 80 6.3.4 HVDC System without Fast Dynamic Isolation . 80 6.3.5 HVDC System with Fast Dynamic Isolation 80 6.4 DC Protection 81 6.4.1 General 81 6.4.2 DC Converter Protections . 81 6.4.3 Protective Shut Down of a Converter 83 6.4.4 DC System Protections . 84

19、6.4.5 DC Equipment Protections . 84 6.5 Clearance of Earth Faults 84 6.5.1 Clearance of a DC Pole-to-Earth Fault . 84 6.5.2 Clearance of a Pole-to Pole Short Circuit . 85 6.5.3 Clearance of a Converter side AC Phase-to-Earth Fault . 85 7 Functional Specifications 85 7.1 General 85 7.2 AC/DC Converte

20、r Stations . 86 7.2.1 DC System Characteristics . 86 7.2.2 Operational Modes. 89 7.2.3 Testing and Commissioning . 95 PD CLC/TR 50609:2014CLC/TR 50609:2014 6 7.3 HVDC breaker . 96 7.3.1 System Requirements . 96 7.3.2 System Functions 96 7.3.3 Interfaces and Overall Architecture . 96 7.3.4 Service Re

21、quirements . 96 7.3.5 Technical System Requirements . 96 Annex A (informative) HVDC Grid Control Study 99 Annex B (informative) Fault Behaviour of Full Bridge Type MMC 106 B.1 Introduction 106 B.2 Test Results 106 B.3 DC to DC Terminal Faults 106 B.4 DC Terminal to Ground Faults 107 B.5 Conclusion 1

22、07 Bibliography . 119 PD CLC/TR 50609:20147 CLC/TR 50609:2014 Foreword This document (CLC/TR 50609:2014) has been prepared by CLC/TC 8X “System aspects of electrical energy supply”. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.

23、CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. This document has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association. This document was already sent out within CLC/TC 8X for comments and th

24、e comments received were discussed within CLC/TC 8X/WG 06 and were incorporated in the current document as far as appropriate. PD CLC/TR 50609:2014CLC/TR 50609:2014 8 0 Introduction 0.1 The European HVDC Grid Study Group Existing power systems in Europe have been developing for more than 100 years t

25、o transmit the power, generated mainly by fossil and nuclear power plants to the loads. Climate change, limited fossil resources and concerns over the security of nuclear power are drivers for an increased utilization of renewable sources, such as wind and solar, to realize a sustainable energy supp

26、ly. According to the geological conditions, the location of large scale renewable energy sources is different to the location of existing conventional power plants and imposes new challenges for the electric power transmission networks, such as extended transmission capacity requirements over long d

27、istances, load flow control and system stability. The excellent bulk power long distance transmission capabilities, low transmission losses and precise power flow control make High Voltage Direct Current (HVDC) the key transmission technology for mastering these challenges, in particular for connect

28、ion of offshore wind power plants to the onshore transmission systems. While the power system reinforcement is already underway by a number of new point-to-point HVDC interconnections, the advantages offered by multiterminal HVDC systems and HVDC grids become more and more attractive. Examples are g

29、rid access projects connecting various wind power plants or combining wind plants with point-to-point transmission, e.g. in the North and Baltic Seas. Multiterminal projects are already in execution and there is planning for pan-European HVDC grids. In this document, multiterminal HVDC systems and H

30、VDC grids are referred to as HVDC Grid Systems. To become reality, HVDC Grid Systems need, in addition to the necessary political framework for cross country system design, construction and operation, competitive supply chains of equipment capable of operating together as an integrated system. This

31、marks a significant change in the HVDC technology market. While today - with very few exceptions a HVDC transmission system has been provided by a single manufacturer, future HVDC Grid Systems will be built step by step composed of converters and HVDC substations supplied by different manufacturers.

32、 Interoperability will thus become a fundamental requirement for future HVDC technology. Common understanding of basic operating and design principles of HVDC Grid Systems is seen as a first step towards multi vendor systems, as it will help the development for the next round of European multitermin

33、al projects. Furthermore, it will prepare the ground for more detailed standardization work. Based on an initiative by the DKE German Commission for Electrical, Electronic and Information Technologies, the European HVDC Grid Study Group has been founded in September 2010 to develop “Technical Guidel

34、ines for first HVDC Grids”. The Study Group has the following objectives: to describe basic principles of HVDC grids with the focus on near term applications; to develop functional specifications of the main equipment and HVDC grid controllers; to develop “New Work Item Proposals” to be offered to C

35、ENELEC for starting standardization work. CIGR SC B4, CENELEC TC8x and ENTSO-E and “Friends of the Supergrid” are involved at an informative level with the results of the work. Members affiliated with the following companies and organizations have been actively contributing to the results of the Stu

36、dy Group achieved so far: 50 Hz Transmission, ABB, ALSTOM, Amprion, DKE, PD CLC/TR 50609:20149 CLC/TR 50609:2014 TransnetBW, Energinet.dk, ETH Zurich, National Grid, Nexans, Prysmian, SEK, Siemens, TenneT and TU Darmstadt. As a starting point the Study Group has been investigating typical applicatio

37、ns and performance requirements of HVDC Grid Systems. This information helps elaborating the basic principles of HVDC networks, which are described in the following clauses: Clause 3, Typical Applications of HVDC Grids; Clause 4, Principles of DC Load Flow; Clause 5, Short-Circuit Currents and Earth

38、ing; Clause 6, Principles of HVDC Grid Protection. From the technical principles described, functional specifications for the main equipment of HVDC networks are derived and summarized in Clause 7. 0.2 Technology 0.2.1 Converters HVDC transmission started more than 60 years ago. Today, the installed

39、 HVDC transmission capacity exceeds 200 GW worldwide. The vast majority of the existing HVDC links are based on so-called Line-Commutated-Converters (LCC). LCC today are built from Thyristors. The power exchange of such converters is determined by controlling the pointon-wave of valve turn-on, while

40、 the turn-off occurs due to the natural zero crossing of valve current forced by the AC network voltage. That is why LCC rely on relatively strong AC systems to provide conversion from AC to DC and vice versa. With so-called Voltage Sourced Converters (VSC), a different type of converters has been i

41、ntroduced to HVDC transmission slightly more than a decade ago. VSCs today utilize Insulated Gate Bipolar Transistors (IGBT) as the main switching elements. IGBTs have controlled turn-on as well as turn-off capability making the VSCs capable of operating under weak AC system conditions or supplying

42、power systems where there is no other voltage source, also referred to as passive networks. The evolution of VSC transmission was started with so-called Two-Level converters at the end of the 1990s and has commenced to Three Level Converters and further to Modular Multilevel Converters (MMC) which h

43、ave made their break-through in the mid to late 2000s. All MMC type converters apply the same principle of connecting a number of identical converter building blocks in series. However, at the present time there are basically two types of such building blocks: referred to as Half-Bridge (HB) and Ful

44、l-Bridge (FB) modules. Other converter equipment which have been proposed for HVDC Grid applications, such as DC/DC converters, load flow controllers, etc. are not discussed in this document. 0.2.2 DC Circuit Similar to AC networks, HVDC transmission systems can be distinguished by their network top

45、ologies as radial and/or meshed networks and with respect to earthing in effectively grounded and isolated systems. Both aspects influence the design criteria and the behaviour of the HVDC system. PD CLC/TR 50609:2014CLC/TR 50609:2014 10 Radial and Meshed Topologies: In radial systems, there is not

46、more than one connection between two arbitrary nodes of the network. The DC voltages of the converter stations connected to each end of a line solely determine the power flow through that line, for example in Figure 1-1, station C is radially connected with station D. In meshed systems, at least two

47、 converter stations have more than one connecting path. Without any additional measures the current through a line will then be determined by the DC voltages of the converter stations as well as the resistances of the parallel connections. In Figure 1-1, the DC circuit connecting stations A, B and C

48、 forms a meshed system while C and D is a radial connection. A HVDC Grid System having a meshed topology can be operated as a radial system if parallel connections are opened by disconnectors or breakers. ABC DFigure 1-1 Example of an HVDC Grid System having a meshed and radial structure Earthing: D

49、C circuits can be effectively grounded if one DC pole is connected to earth through a low ohmic branch. Such systems are also referred to as asymmetrical Monopoles or just “Monopoles”. Two Monopoles of opposite DC voltage polarity are often combined into so-called bipolar systems or just “Bipoles”. Isolated DC circuits do not have a low ohmic connection to ground on the DC side. These configurations are also referred to as “Symmetrical Monopoles”. 0.2.3 Technological Focus of the European HVDC Grid Study Group Various technologies are availab