Dave DickmanderABB Grid Systems, Power Systems Consulting Master-Untertitelformat bearbeiten Mastertitelformat bearbeiten WECC HVDC Task Force Modeling of HVDC © ABB Group July 12, 2011 | Slide 1 HVDC by ABB 2010 1954 In between Gotland HVDC transmission © ABB Group July 12, 2011 | Slide 2 20 MW ± 100 kV 61 HVDC Classic projects and 15 HVDC Light projects 14 HVDC upgrade projects >50% global market share Continuous technology leaps XiangjiabaShanghai 6,400 MW ± 800 kV HVDC by ABB Hällsjön Nelson River 2 Highgate CU-project Châteauguay Vancouver Island Pole 1 Outaouais QuebecNew England Rapid City EWIC English Channel Dürnrohr Sardinia-Italy Sapei Square Butte Cross Sound Pacific Intertie Eagle Pass Sharyland Pacific Intertie Upgrading Pacific Intertie Expansion Intermountain IPP Upgrade Blackwater Estlink NorNed NordBalt Gotland 1-3 Gotland Light Konti-Skan SwePol Tjæreborg Baltic Cable BorWin1 DolWin1 Kontek Hülünbeir- Liaoning Lingbao II Extension Italy-Greece Rio Madeira Itaipu Inga-Shaba Caprivi Link Apollo Upgrade Cahora Bassa Brazil-Argentina Interconnection I&II 61 HVDC Classic Projects since 1954 14 HVDC Classic Upgrades since 1990 16 HVDC Light Projects since 1997 © ABB Group July 12, 2011 | Slide 3 FennoSkan 1&2 Troll Skagerrak 1-3 Skagerrak 4 Valhall ChaPad Vizag II Rihand-Delhi Three Gorges-Changzhou Three Gorges-Shanghai Sakuma Gezhouba-Shanghai Xiangjiaba-Shanghai Jinping - Sunan Three Gorges-Guandong Leyte-Luzon Broken Hill Vindhyachal New Zealand 1&2 North East Agra Directlink Murraylink HVDC Models for Planning Studies What do I need to know about HVDC? What Basic Information on HVDC do I Need? How can I model HVDC in: Powerflow Studies Stability Studies What are the System Benefits? Relevant Project Examples? © ABB Group July 12, 2011 | Slide 4 Classic HVDC Station Components AC yard 11th harmonic filter Converter DC yard Valve hall Pole line 13th harmonic filter DC filter Highpass filter Electrode lines Highpass filter 13th harmonic filter Pole line 11th harmonic filter © ABB Group July 12, 2011 | Slide 5 AC bus 2011 | Slide 6 .HVDC Classic System Characteristics DC-Side impedance is dominated by smoothing reactor High impedance of smoothing reactor is reflected to AC side of converter High Internal Impedance => Current Source HVDC Controls: Current regulator with outer power control loop Powerflow representation: Load Model © ABB Group July 12. 0 PU) Qcon = -0.HVDC Classic Powerflow Model Pcon = +1.5 PU (-0. 2011 | Slide 7 .5 PU © ABB Group July 12.5 PU) Qcap= +0.0 PU (-1. Classic HVDC Reactive Power Balance © ABB Group July 12. 2011 | Slide 8 . 2011 | Slide 9 Thermal loading Reactive power requirements Power transfer limits and changes in the system power flow Voltage profiles System losses .HVDC Simplified Powerflow Models Preliminary Screening of Certain Criteria: © ABB Group July 12. u (firing. 2011 | Slide 10 DC Voltages Converter P & Q DC Currents α. extinction. γ.HVDC Classic Detailed Powerflow Models Provide HVDC System Operating Parameters: • • • • • • © ABB Group July 12. and overlap angles) Converter Transformer Taps DC System Losses . 2011 | Slide 11 3 π ⋅ X C ⋅ Id Typical estimates.12%) of UdN /6-pulse bridge.065 drN= 0.3/250 pu (0. the equations are essentially the same as those in the PSS/E Manual.. and UT is neglected. U vN = I vN = π U di 0 N 3 ⋅ 2 2 ⋅ I dN 3 .ABB HVDC Classic Main Circuit Calculations 3 X C I dN dx = ⋅ π U di 0 N U dr = U di 0 R cos(α ) − © ABB Group July 12.e. Nominal conditions: α=15 degrees dxN= 0. negligible Equations per 6-pulse bridge Once the above definition of dx is taken into account.003 UT=0. i. ABB HVDC Classic Operating Principles 6-Pulse Rectifier © ABB Group July 12. 2011 | Slide 12 Equivalent Circuit . 2011 | Slide 13 Inverter Operation .ABB HVDC Classic Operating Principles Rectifier Operation © ABB Group July 12. HVDC Classic Detailed Powerflow Models • A more detailed powerflow model of HVDC is necessary in order to be able to initialize the dynamic model. • It is also useful for providing the approximate steady-state response of HVDC to changes in terminal voltage during powerflow studies. 2011 | Slide 14 . © ABB Group July 12. min MW MW kV kV kA kV kV kV kA Line side voltage. EBASR kV TRR Ratio XCR Reactance Ohm RCR Resistance Ohm Tap.Example of Data for Entry into PSS/E Bridges in series PdN. max Tap. VSCHEDULE UdN 12puls IdN alphaN dxN drN UT Udi0N UvN IvN Tap. step pu TMXR. bipolar. bipolar. SETVAL PdN 12puls UdN. min tap pu © ABB Group July 12. max tap pu TMNR. 2011 | Slide 15 . Monopolar HVDC Transmission © ABB Group July 12. 2011 | Slide 16 . 2011 | Slide 17 .Effect of Current Margin © ABB Group July 12. 2011 | Slide 18 Complete Characteristics .VDCOL and Complete Characteristics VDCOL Function © ABB Group July 12. network Defines a fast and controlled restart after clearance of a. 2011 | Slide 19 Main characteristics With/Without VDCOL Avoids power instability during and after disturbances in the a.c.c. and d. faults Avoids stresses on the thyristors at continuous commutation failure Suppress the probability of consecutive commutation failures at recovery .c.HVDC Classic Control VDCOL Function VDCOL characteristics © ABB Group July 12. HVDC Classic Dynamic Model Uac AC System Δf ΔP ΔΦ + Iac Ud _ α Id Δ Uac FPD GR ΔI DCR ΔP Imargin PC VDCOL _ CCA P Order CCA: Current Control Amplifier VDCOL: Voltage-Dependent Current Order Limiter GR: Voltage (Gamma) Regulator PC: Power Control DCR: Power-Frequency Regulator FPD: Power-Frequency Measurement © ABB Group July 12. 2011 | Slide 20 . 2011 | Slide 21 Frequency Control Modulation for System Stabilization System Oscillation Damping Reactive Power Control AC Voltage Control Fast Remedial Action Responses .HVDC High-Level Controls Enhancement of System Performance by High-Level Controls: © ABB Group July 12. others Power modulation to increase system stability: Vindhyachal (India). others Control of frequency on islanded systems: IPP. others Voltage stabilization of weak ac network Blackwater. HQ-NEH Phase II. New Zealand © ABB Group July 12. 2011 | Slide 22 .HVDC High-Level Controls Examples of System Performance Enhancement: Power step runback or step increase: IPP. cosctlang GE has increased limits for “dcmt” for latest models © ABB Group July 12.HVDC Classic Modeling in PSLF Recent development focus is on PSLF “dcmt” model EPCL-PSLF interface via dcc[@index]. 2011 | Slide 23 . 2011 | Slide 24 Pole Loss Compensation .IPP Southern Transmission System (STS) Milford Wind (MWC) Interconnection: 400 MW Wind Power Wind Scheduled over HVDC Integration with 1920 MW IPP STS Integration with 2400 MW Upgrade IPP PSLF Model: Current Regulator (CCA) VDCOL Wind Power Controls DC Power Schedule Calculator Frequency Controls: Constant Frequency Control Frequency Control with Deadband © ABB Group July 12. IPP STS – PSLF Model Results © ABB Group July 12. 2011 | Slide 25 . 2011 | Slide 26 System Characteristics: 200 MW bi-directional 3-winding converter transformers Weak AC system on PNM side SVC mode Blackwater PSLF Model: Current Regulator (CCA) AC VDCOL AC Voltage Regulator DC Voltage Regulator SVC Regulator .Blackwater HVDC Back-to-Back © ABB Group July 12. Blackwater PSLF Model Results © ABB Group July 12. 2011 | Slide 27 . VSC Compared to HVDC Classic HVDC Classic .Voltage Source Converters (VSC) © ABB Group © ABB Slide 28Group July 12.Current Source Converters (CSC) Line-commutated thyristor valves Requires 50% reactive compensation (35% HF) Minimum short circuit capacity ~2x converter rating Telecommunication between stations for best performance Significant inherent short term overload capability Reversal of power requires polarity reversal of the DC voltage (takes time) HVDC Light . 2011 | Slide 28 PowDoc id Self-commutated IGBT valves allows for independent control of P and Q Compact design due to a minimum of filters and reactive compensation Standard transformers without DC exposure Black start possible / Islanded wind farms Low short circuit conditions Reversal of power can be made instantaneously by current reversal . 2011 | Slide 29 PowDoc id + Ud . 1997-2001 Two-level High Converter switching frequency Filters required Two-level converter phase-to-neutral voltage © ABB Group © ABB Slide 29Group July 12.Ud .HVDC Light Historical Review Generation 1. Ud Three-level converter phase-to-neutral voltage © ABB Group © ABB Slide 30Group July 12.HVDC Light Historical Review Generation 2. 2002-2004 Three-level Converter Switching frequency reduced Harmonic generation + Ud improved . 2011 | Slide 30 PowDoc id . 2011 | Slide 31 PowDoc id .HVDC Light Historical Review Generation 3. 2005-2009 Two-level Converter Optimized IGBT + Ud switching frequency .Ud Lower Two-level converter phase-to-neutral voltage © ABB Group © ABB Slide 31Group July 12. 2011 | Slide 32 .HVDC Light (3G) Station Components © ABB Group July 12. HVDC Light Historical Review Generation 4.Ud © ABB Group © ABB Slide 33Group July 12. 2010-Present + Ud Cascaded Two-level Converter Excellent .Ud + Ud output voltage quality Scalable to high voltages . 2011 | Slide 33 PowDoc id . cap charges when current is positive . Cell is Inserted. Cell is Bypassed T1 off. T2 on: Uo = Ui – Uc. current conducted only through diodes. cap charges when current is positive T1 off.HVDC Light (4G) Cell Ui + T1 Uo Uc - © ABB Group July 12. T2 off: Uo=Ui. T2 off: Cell is blocked. 2011 | Slide 34 T2 T1 on. 2011 | Slide 35 .HVDC Light (4G) Operating Principles Cascaded Two-Level (CTL) Converter Low Switching Frequency Per Cell Multiple Cells give High Effective Switching Frequency © ABB Group July 12. 2011 | Slide 36 .HVDC Light (4G) Station Components © ABB Group July 12. closed Disconnector. open Switch.Three terminal configurations Symmetric monopoles + + - - Disconnector. 2011 | Slide 37 PowDoc id . closed + Switch. open © ABB Group © ABB Slide 37Group July 12. open Switch. closed Switch. 2011 | Slide 38 PowDoc id . closed + Disconnector.Three terminal configurations Bipole with metallic neutral + + - - Disconnector. open © ABB Group © ABB Slide 38Group July 12. 2011 | Slide 39 PowDoc id .HVDC Light Reference Projects © ABB Group © ABB Slide 39Group July 12. HVDC Light System Characteristics DC-Side Impedance Dominated by DC Capacitor Low Impedance of DC Capacitor is Reflected to AC Side Low Internal Impedance => Voltage Source Controls may be configured to impart a current source behavior at fundamental frequency (vector current control) Powerflow Representation: Generator © ABB Group July 12. 2011 | Slide 40 . 0 PU (-1.35 PU Qmin = -0.0 PU) Qmax = +0.HVDC Light Steady-State Model Power Flow Modeling Pcon = +1.50 PU Qcap = 0 PU ! © ABB Group July 12. 2011 | Slide 41 . HVDC Light Converter Characteristics System Parameters Valve current Modulation index AC and DC voltage DC cable rating Cell voltage © ABB Group © ABB Slide 42Group July 12. 2011 | Slide 42 PowDoc id . 2011 | Slide 43 .HVDC Light Power Flow Model Two Power Flow “Generators” © ABB Group July 12. Q I X Uv UL X UL © ABB Group July 12.HVDC Light System Principles P. 2011 | Slide 44 Uv UL ⋅ Uv ⎧ ⋅ sin(δ) P= ⎪ X ⎪ ⎨ ⎪ U L ⋅ ( U L − U v ⋅ cos(δ)) ⎪Q = X ⎩ . Independent control of active and reactive power Step in active power order © ABB Group © ABB Slide 45Group July 12. 2011 | Slide 45 PowDoc id . 2011 | Slide 46 Imparts “Synchronous Machine” Behavior to VSC .VSC Converter Control Methods (Literature) Vector-Current Control: Dominant Method of Controlling VSC Converter current is controlled directly Passive Network Control: VSC Sets Voltage Magnitude and Angle AC Network Determines VSC Power Power-Angle Control: VSC Calculates Voltage and Angle for Desired P and Q Converter current is not limited (disadvantage) Power-Frequency Control: © ABB Group July 12. HVDC Light Vector-Current Control PCC PCC Udc Upcc Uac ref Uac ref Qref Qref © ABB Group July 12. 2011 | Slide 47 AC voltage control Reactive power control Inner current control Phase current limit Converter voltage limit DC voltage control Active power control Udc ref Pref Pref UacCtrl UdcCtrl QCtrl PCtrl . vscdc1[@mx].eq.angle (when phase reactor impedance is included) © ABB Group July 12.ed. “vscdc1” models EPCL interface via vscdc1[@mx]. 2011 | Slide 48 . vscdc1[@mx].HVDC Light Modeling in PSLF Development focus is on PSLF “vscdc”. 2011 | Slide 49 .HVDC Light Model Benchmarking © ABB Group July 12. HVDC Light Dynamic Performance © ABB Group July 12. 2011 | Slide 50 . 2011 | Slide 51 .HVDC Light Dynamic Performance P Q VA VB VC © ABB Group July 12. 2011 | Slide 52 PSLF .ABB HVDC Model Availability (Detailed Models) PSS/E HVDC Type Available (Yes/No) Available (Yes/No) HVDC Conventional Yes Yes* HVDC CCC Yes Pending HVDC Light – Vector Current Control Yes Yes* HVDC Light – Passive Network Control Yes Pending * Modifications may be required depending on specific configuration to be studied © ABB Group July 12. 2011 | Slide 53 .© ABB Group July 12.
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