J. Dorn, September Hochspannungsgleichstromübertragung (HGÜ) eine Schlüsseltechnologie für unsere Stromversorgung

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1 J. Dorn, September 2016 Hochspannungsgleichstromübertragung (HGÜ) eine Schlüsseltechnologie für unsere Stromversorgung

2 Introduction and Basics Converter Topologies in HVDC and used Semiconductors Technology of Line-Commutated Current Sourced Converters (LCC) and project examples Technology of Self-commutated Voltage Sourced Converter (VSC) and project examples Summary Page

3 Introduction and Basics Converter Topologies in HVDC and used Semiconductors Technology of Line-Commutated Current Sourced Converters (LCC) and project examples Technology of Self-commutated Voltage Sourced Converter (VSC) and project examples Summary Page

4 Fundamental changes in the business of electrical energy From centralized power and unidirectional grid Distributed Energy Systems to Decentral and Distributed Energy Systems and bidirectional balancing Transmission Distribution and Consumption 1 Changing generation mix 2 Generation capacity additions Distance from source to load Decentralization (public/private) Refurbishment/ upgrades Page

5 What is HVDC? Why HVDC? AC Grid 1 AC Grid 2 P DC Compared to AC transmission HVDC has a number of advantages: Long overhead lines with high transmission Capacity, low transmission losses and reduced right-of-way Cable transmissions with low losses and without limitation in length Asynchronous grids can be interconnected Increase of transmission capacity without increasing short circuit currents Fast control of power flow, independent from AC conditions Firewall against cascading disturbances, active power oscillation damping Page

6 Comparison of Tower Geometry AC vs. DC Comparison of Towers for 800 kv AC Line a) and 500 kv DC Line b), at same Transmission Capacity of 3,000 MW Page

7 HVDC Applications Long Distance OHL AC System A DC Line AC System B DC Cable AC System A DC Cable AC System B Back-to-Back AC System A AC System B Page

8 HVDC Classic vs. VSC HVDC AC Grid 1 AC Grid 2 P DC HVDC Classic Line-commutated current-source converter (LCC) Thyristors with turn-on capability only VSC HVDC Self-commutated voltage-source converter (VSC) Semiconductor Switches with turn-on and turn-off capability, IGBTs Page

9 Introduction and Basics Converter Topologies in HVDC and used Semiconductors Technology of Line-Commutated Current Sourced Converters (LCC) and project examples Technology of Self-commutated Voltage Sourced Converter (VSC) and project examples Summary Page

10 HVDC Classic: Basic Converter Design I d L d R d U A,f A V d,a V d,b U B, f B Conv. A I d Conv. B L d R d V d,b V d,a n e.g. 75 Page

11 Key Components of a typical Bipolar Classic HVDC Converter Station AC System A AC System B Controls, Protection, Monitoring To/ from other terminal DC filter Pole 1 AC V d,a filter DC filter Pole n e.g AC Switchyard 2. AC Filters 3. Transformers 4. Converter Valves / Valve Hall 5. Smoothing Reactors and DC Filters 6. DC Switchyard Page

12 Sperrspannung Blocking Voltage in kv [kv] Si Area in mm² Development of Thyristor Blocking Voltages and Silicon Area in HVDC Converters 10,0 9, thyristors / 1000 MW (for both stations) Direct Light Triggering 800 thyristors / 1000 MW 8.5kV , ,0 DC-Current: 6250 A , A, , , , , kV 1,0 1,5 '' < 600 0, thyristors / 1000 MW Page

13 HVDC Thyristor Module (2x13 Thyristors) Seite

14 Suspended Thyristor Modules ensure excellent seismic Performance (Gui-Guang I) Page 15 Copyright Siemens AG

15 HVDC Classic Valve Hall and Station Seite

16 COMETA, Spain-Mallorca DC Interconnector Indoor AC Yard *Station St. Ponsa Page

17 The 800 kv Xiangjiaba-Shanghai Project Length of DC Line: 2071 km DC Voltage: 800 kv DC Current: 4000 A (continuously) Transmission Capacity: 6400 MW (continuously) Page

18 800 kv Converter Station Seite

19 UHVDC 800 kv Valve Hall AC Bushings and Transformer Circuitry Seite

20 800 kv Overhead Line Xiangjiaba-Shanghai 6400MW with these two lines 4000A 4000A +800kV -800kV Seite

21 Introduction and Basics Converter Topologies in HVDC and used Semiconductors Technology of Line-Commutated Current Sourced Converters (LCC) and project examples Technology of Self-commutated Voltage Sourced Converter (VSC) and project examples Summary Page

22 General features of VSC HVDC Grid access of weak AC networks High dynamic performance Independent control of active and reactive power Supply of passive networks and black start capability Small space requirements Seite

23 VSC Technology Two-level converter U d /2 U d / 2 u1( t) u1_pulse( t) -U d / Desired voltage 0 t 0.02 Realized voltage U conv U d / 2 Generation of harmonics and HF High efforts for components, filtering and shielding Necessary components per level: Power semiconductors, RC snubber, DC grading resistor, power supply, gate driver with active clamping, level monitoring, cooling plates Page

24 Modular Multilevel Converter (MMC) Approach U dp U d UU aconv U dn Advantages: Small Voltage Steps Small rates of voltage rise Low switching frequencies Low emission of electromagnetic HF fields Filters and shielding usually not necessary Low electrical losses Seite

25 MMC Modularity PLUSCONTROL TM 1 2 n PM Electronics n Phase Unit Submodule Seite

26 Converter arms operated as controlled voltage sources U dc / n u c (t) n - U dc / 2 Seite

27 Voltage generation AC and DC Voltages controlled by Converter Module Voltages: +U dc / n u c (t) u1_step ( t) 2 U1 0 2 U1 u c (t) - U dc / t n Seite

28 All currents controlled by converter arm voltages I dc U dc / n i ac (t) i ac (t)/2 i ac (t)/2 I d /3 u c (t) U dc / 2 n Seite

29 High system availability and reliability due to redundancy concept Requirements: No interruption of operation in case of a level fault A level fault does not influence surrounding 1 2 n High-Speed Bypass Switch SM Electronics + Solution: Built-in level redundancy (some percent) Fast and high-reliable bypass-switch 1 2 n Phase Unit Submodule (SM) Seite

30 Handling of DC pole-to-pole fault by using a protection thyristor 1 2 SM Electronics n IGBT1 D1 1 IGBT2 D n Seite

31 Modularer Aufbau des Stromrichters (1) Seite Source: Siemens AG

32 Modularer Aufbau des Stromrichters (2) Seite Source: Siemens AG

33 Components and subsystems AC System A DC Cable AC System B Switchyard Transformers Star Point Reactor Insertion Resistor Bypass Switch MMC Converter Reactors DC Switchyard Transmission Path To/ from other Station Seite Current Measuring Devices Control, Protection and Monitoring System

34 Transbay Cable: Bird s eye view Seite Source: Siemens AG

35 Increase of Power Rating of MMCs Transbay Cable 400 MW 2010 Commercial operation. HelWin MW 2014 HelWin MW 2015 SylWin MW 2015 All platforms in commercial operation! BorWin MW 2015 Inelfe 2 x 1000 MW 2015 Commercial operation. BorWin MW 2019 Seite

36 INELFE, France-Spain Overview Customer Project Name INELFE (RTE and REE) INELFE Location Balxas, France Santa Llogala, Spain Power Rating Type of Plant Voltage Levels 2 x 1000 MW HVDC PLUS ± 320 kv DC AC 400 kv, 50 Hz Distance Semiconductors 65 km underground cable IGBT Seite

37 INELFE, France-Spain Worldwide biggest VSC HVDC System with 2000 MW capacity Seite

38 Introduction and Basics Converter Topologies in HVDC and used Semiconductors Technology of Line-Commutated Current Sourced Converters (LCC) and project examples Technology of Self-commutated Voltage Sourced Converter (VSC) and project examples Summary Page

39 Comparison of LCC and VSC technology Line-commutated Converter Technology: Reactive power demand High efforts for filtering Requirements for short circuit power Block of converter in case of AC faults Very low losses Operational experience since middle of last century DC current up to 6.25 ka plus additional overload capability ( 10 +/- 800kV) Higher efforts for multi-terminal systems due to polarity reversal Inherent DC fault clearing capability Self-commutated VSC Technology: Reactive power controllable Low or even no filtering efforts resulting on lower space requirement Weak and passive networks can be connected; black start capability Fault ride through capability Slightly higher losses Relatively young technology Maximum DC current per converter around 2 ka Multi-terminal simpler due to fixed voltage polarity Full bridge converter needed for inherent DC fault clearing capability Best solution depends on required transmission capacity, other requirements and circumstances Seite

40 Thank you for your attention Jörg Dorn Head of R&D Transmission Solutions Siemens AG