Trends and Control Challenges in Renewable Energy Systems
Pedro Rodriguez Ph.D. Terrassa, Spain March 2nd, 2012
X SIMPOSIO CEA DE INGENIERIA DE CONTROL Outline
• Seer presentation
• Wind power plants
• PV pppower plants
• Ongoing PhD research projects
• Conclusions
06.03.12 2 Outline
• Seer presentation
• Wind power plants
• PV pppower plants
• Ongoing PhD research projects
• Conclusions
06.03.12 3 seer
…a research center on renewable electrical energy systems
06.03.12 4 seer
Director
Pedro Rodríguez received the M.Sc. and Ph.D. degrees in electrical engineering from the Technical University of Catalonia (UPC), Spain, in 1994 and 2004, respectively. He was a Postdoctoral Researcher at the Center for Power Electronics Systems (CPES), Virginia Tech, Blacksburg in 2005, and at the Department of Energy Technology, Aalborg University (AAU) in 2006. He joined the faculty of UPC as an Assistant Professor in 1990, where he became the Director of the research center on Renewable Electrical Energy Systems (SEER) in the Department of Electrical Engineering. He was also a Visiting Professor at the AAU from 2007 to 2011, acting as a co‐supervisor of the Vestas Power Program. He still lectures Ph.D. courses at the AAU every year. From 2011, he is the Head of Electrical Engineering division in Abengoa Research, although he is still joined to the UPC as a part time Professor. He has coauthored one book and more than 100 papers in technical journals and conference proceedings. He is the holder of seven licensed patents. His research interests include integration of distributed generation systems, smart grids, and design and control of power converters.
Dr. Rodriguez is a senior member of the IEEE, a member of the administrate committee of the IEEE Industrial Electronics Society (IES), the general chair of IEEE‐IES Gold and Student Activities, the vice‐chair of the Sustainability and Renewable Energy Committee of the IEEE Industry Application Society and a member of the IEEE‐IES Technical Committee on Renewable Energy Systems. He is an Associate Editor of the IEEE Transaction on Power Electronics.
06.03.12 5 seer Missi on
The objective of SEER is to conduct leading edge research at internationally excellent level in the fields of distributed electric power systems by making an intensive use of power processing based on power electronics and advance control techniques.
The research activities conducted by SEER are primarily focused on renewable energies, mainly to photovoltaic and wind energy, and our mission is:
to make large scale integration of renewable energies a reality into the smart electric power networks of the future. .
06.03.12 6 seer RhResearch Areas
06.03.12 7 seer PjtProjects Improvement of power systems stability by using FACTS bdbased on WTGs (WTGFACTS) Maximizing the wind energy connected to the grid, guaranteeing the correct operation and the stability of the power system.
06.03.12 8 seer
One of the largest and most comprehensive partnership ever made between the worldwide No.1 wind turbine producer and an university,
the Vestas Power Programme
06.03.12 9 seer the PhD/PostDoc dream team…
PE 1‐Control of Grid connected PS 1 ‐ Wind power plant control for HVDC Converters for Large WT connection PhD Hernan Miranda PhD Sanjay Chhdhaudhary Started 1 July 2008 Started 1 July 2008
PE 2 ‐ High power‐density PS 2 ‐ Wind power plant control converter for Large WT for AC connection PhD Osman Senturk PhD MMfitufit Altin Started 1 July 2008 Started 15 Sep 2009 PE 3‐Advanced Control of Grid PS 3 ‐ FACTS based Connection off WPP Connected Converter for LWT to the Grid PhD Omer Gosku PhD AAdndzrej Adamczy k Star te d 1 Started 15 Sep 2009 July 2009
ES 1 ‐ Storage System for Large PS 4 ‐ Optimization of VSC‐HVDC WTPenetration Transmission in WPP PhD MMijaciej SiSwierczyns ki PhD RRdiodrigo da Silva Started 1 July 2009 Started 15 Sep 2009 ES 2 ‐ Storage Systems in Power PS 5 ‐ Power plant and power system Systems control and operation PostDoc Claus Rasmussen PostDoc Ravindra N. Mukerjee Started 1 sep 2008 Started 1 July 2009
06.03.12 10 seer PjtProjects Mini‐Wind Turbine. Aerotec 15 kW • Aerodynamic design • Mechanic design • Strucutral design • Electrical design • Supervision and control design
06.03.12 11 seer PjtProjects Smart Power Filter for Wind Systems (SMARTFILT) SMARTFILT entails research and development activities on a new generation of hybrid power filters specially designed for wind generation systems
06.03.12 12 seer PjtProjects FB10 and MLC2 power converters
06.03.12 13 seer PjtProjects Smart PV Generation with Energy Storage (SMART‐PV) Power Processing + Energy Storage + Grid Support Services
1200 PV production (1kW) 4 steps redistribution 1 step 6h redistribution 1000 1 step 10h redistribution 1 step 14h redistribution
n (W) 800
600
400 Power Generatio Power 200
0 100 200 300 400 500 600 700 Time (2 minute intervals)
06.03.12 14 seer PjtProjects Advanced Process of Power and Energy . Design of the power processing system for High Density PV Systems . Improvement of the efficiency of PV plants based on High Density PV panels . Implementation of Grid Support functionalities . Development of ESS for PV plants . 3 worldwide patents
06.03.12 15 Introduction
Distributed generation employs descentralized generation, storage, protection and control technologies to change the structure of the electrical power systems and improve their performance.
06.03.12 16 Outline
• Seer presentation
• Wind power plants
• PV pppower plants
• Ongoing PhD research projects
• Conclusions
06.03.12 17 Wind Power Markets Installed wind power in the World
• Record installation of 43.9 GW expected for 2011. • Cumulative installed capacity by June 2011 reached 215 GW • China is the No. 1 market in the world, with a share of 43 %, adding 8 GW. • 101 new offshore wind turbines in Europe, totalling around 1, 800 MW of installed by the first semester of 2011, most of them in UK
06.03.12 18 Wind Power Markets Top-10 suppliers (global) in 2010
Some data about manufacturers • Vestas Wind Systems maintained its position as the largest manufacturer of wind turbines in the world in 2010, both in terms of annual installations and cumulative installed capacity • Sinovel entered the Top 10 list in 2007 and became the second largest in the world in 2010. • GE Energy is the third largest wind turbine manufacturer in the world.
06.03.12 19 Wind Power Markets Global wind power market in Europe
06.03.12 20 Wind Turbines Wind turbines with huge heights and diameters
• Bigger and more efficient ! • 3.6-7MW prototypes running (Vestas, GE, Siemens Wind,Enercon, Gamesa, Alstom Wind,…) • 2 MW WT are still the "best seller" on the market but higher powers are knocking the door
06.03.12 21 Wind Turbines Two main WT concepts
Generator with gear-box Direct drive generator
06.03.12 22 Wind Turbines Vestas Wind Systems A/S Denmark
Vestas V164 off-shore turbine Rated power: 7,000 kW Rotor diameter: 164 m Hub height: min. 105m Turbine concept: medium-speed gearbox, variable speed, variable pitch, full-scale power converter Generator: permanent magnet Prototype: 2012
06.03.12 23 Wind Turbines Enercon GmbH Germany
Enercon E-126 direct drive turbine Rated power: 7,500 kW Rotor diameter: 127 m Hub heegigh t: 135 m Turbine concept: Gearless, variable speed, variable pitch control Generator: Enercon direct-drive annular generator Prototype: 2007
06.03.12 24 Wind Turbines Nordex Germany
NdNordex N150/6000 Rated power: 6,000 kW Rotor diameter: 150 m Hub height: approx.100 m Turbine concept: Gearless, variable speed, variable pitch control Generator: permanent magnet 3,3 / 4,5 KV Prototype: 2012-13 Series: 2014
06.03.12 25 Wind Turbines Siemens Wind Power Denmark
Siemens SWT-3.6-120 Rated power: 3, 600 kW Rotor diameter: 120 m Turbine concept: 3-stage gear, variable speed, variable pitch control Generator: Asynchronous
New Generation : PM generator, without gearbox
06.03.12 26 Wind Turbines Siemens Wind Power Denmark
Siemens SWT-6.0-120 - DD Rated power: 6,000 kW Rotor diameter: 120 m Turbine concept: Direct drive GtPMGenerator: PM synchronous (690V) Pototype: June 2011, Hoevsoere, DK
06.03.12 27 Wind Turbines Gamesa Eolica Spain
Gamesa G11X Rated power: 4,500 kW Rotor diameter: 128-136 m Turbine concept: 2-stage gear (1:37,88) Generator: PM synchronous with 6 three-phase circuits in parallel G11X-50MW5.0 MW preseries 2013 G114-6-7.0 MW preseries 2014
06.03.12 28 Wind Turbines Alstom Wind France
Haliade 150 Rated power: 6,000 kW Rotor diameter: 150 m Turbine concept: Direct drive Generator: PM synchronous Prototy pes: 2011-12 Pre-series 2013
06.03.12 29 Floating Wind Turbines HyWind (Siemens and StatoilHydro, 2009)
Turbine size: 2.3 MW Displacement: 5300 m3 Turbine weight: 138 tons Diameter at water line: 6m Turbine height: 65 m Diameter sub. body: 8.3 m Rotor diameter: 82. 4 m Water depths: 120-700 m Draft hull: 100 m Mooring: 3 lines
06.03.12 30 Floating Wind Turbines WindFloat (US Principle Power and EDP)
Semi-submersible multi-megawatt wind turbine Designed by: US Principle Power Allocation: Aguçadoura, Portugal Turbine size: 2 MW (()(,Vestas) (3,6 – 10 MW) Assambled onshore and towed and anchored offshore 06.03.12 31 Wind Turbine Accidents A mature but not enough reliable technology sometimes
Dec 9th, 2011. A 300ft wind turbine exploded in flames as it was buffeted by the high winds, Ardrossan, North Ayrshire, Scotland.
06.03.12 32 Wind Turbine Accidents Wind turbine accidents
06.03.12 33 Power Processing High power converters
Medium Voltage Levels: 2.3 kV, 3.3 kV, 4.16 kV, 6.3 kV, ….10 kV, 20 kV Power Range:
2 MW ... 6 MW, 9 MW .... 10 MW, 20 MW March 6, 2012
06.03.12 34 Wind Power Processing Full power converters for WT with gearbox
• All power goes through the power converter, full speed control • AC‐AC decoupling by means of the DC bus • Full active/reactive power control • Low‐voltage ride‐through capability • More expensive and lager converter than in DFIG
06.03.12 35 Wind Power Processing SCIG WT with full power converters
• Back‐to‐back (B2B) 2L_VSC used to handle 100% of the power • In multi‐MW WT, regular power converters are paralleled to handle the high currents • Good and robust concept, though the converter is quite big. • Expensive converter
06.03.12 36 Wind Power Processing PMSG WT multiple windings processed by full power converters
• Multiple generator winding enables distributed power processing instead of paralleling • Operation with fewer winding/converters according operating conditions • Improved efficiency and redundancy (fault tolerant) • Expensive concept with high maintenance
06.03.12 37 Wind Power Processing SG WT with MV full power converters
• Back‐to‐back 3L‐NPC full power converter to handle 100% power • No parallel converters are used • Higher power density, lower losses and lighter conductors thanks to the MV level • MV conversion technology for WT is still an expensive and immature technology
06.03.12 38 Wind Power Processing PMSG WT with distributed drive train and full power converters
• Multi‐shaft gearbox enable the use of multiple small generators (more compact nacelle) • Operation with fewer generators/converters according operating conditions • Improved efficiency and redundancy (fault tolerant) • Complex and expensive gearbox with high maintenance
06.03.12 39 Wind Power Processing Full power converters for direct drive WTs
• Gearbox elimination reduces cost, weight, maintenance, noise and losses • Shorted drive train leads to a shorter nacelle • Strong dependence on rear earth metals • A large diameter is necessary to hold all the poles, leading to more complex generators and mechanisc
06.03.12 40 Wind Power Processing PMSG WT with diode rectifier and boost or buck converter
• A conventional and well‐known boost converter steps the voltage up and control the generator • Cheap, small and simple conversion topology • Simple control • Diode rectifier gives rise to harmonics in the generator which increases stress and losses
06.03.12 41 Wind Power Processing PMSG WT with multi -phase generator , diode rectifier and boost or buck converter
• A 6‐phase generator has a high power densidity • Several interleaved well‐known boost converters handle high currents • A conventional 2L‐VSC with parallel interleaved legs to connect to the grid • Diode rectifier gives rise to harmonics in the generator which increases stress and losses • Many components decrease reliability and increases maintenance
06.03.12 42 Wind Power Processing Some examples of direct drive WTs
06.03.12 43 Offshore Wind Power Offshore wind power potential
06.03.12 44 Offshore Wind Power Plants Nysted (Rødsand I 165 . 6, Rødsand II 209. 3 MW)
• 72 x 2.3MW (Siemens SWT-2.3-93, in operation from Sept 12, 2003 ) • 91 x 2.3MW (Siemens SWT-232.3-93, in operation from Oct 12, 2010)
Siemens SWT-2.3-93
RDiRotor Diameter 93 m Hub Height 80-101 m Weight 336-436 tons Min/Max rotation speed 6/16 rounds/minute Min/Nom/Max Wind 4/13/25 m/s Gear box Yes (1:91) Generator ASYNC (1900 rpm)(690-740 V) (ABB)
06.03.12 45 HVAC and HVDC AC vs. DC
Thomas Alva Edison, in 1878 Nikola Tesla, in 1896 • AC voltages and currents can easily change their amplitude by using transformers • AC was easily transmitted over long distances at high voltage and low currents (low losses) • AC transmission is mainly based on three‐phase systems (three conductors) • DC power conversion was seen as non‐reliable technology • DC is more difficult to interrupt than AC • DC can be efficiently processed today through power electronics • DC has been used from the beginning to meet demand there where it was needed (distributed generation) • DC electricity can be naturally stored in batteries
06.03.12 46 HVAC and HVDC AC lines reactive power charging
• Lines and cables act as capacitors • When energized a charging current is generated • For DC lines, energizing occurs only once • For AC charged and discharged each half‐ period • Reactive Power charging is proportional to: • voltage squared • length of cable • frequency • In practice AC cables longer than 100km are not practical • Problem does not exist for DC cables
06.03.12 47 HVAC and HVDC Power transfer capability
• AC and DC capacity increases with square of voltage • AC transfer capacity diminishes dramatically with distance, due to reactive power charging • AC transfer capacity diminishes with distance, due to voltage and angle stability limit • For AC – Switching stations are required every ~400kms • DC transfer capacity almost unaffected by distance
06.03.12 48 HVAC and HVDC Study case for a 300 MW offshore WPP
) 250,00 €€
200,00 Cost (M n n 150,00 D*dist*cap C*capacity Connectio 100,00 BBdistance*distance A Total 50,00
0,00 HVAC 50 km HVAC 100 HVDC 50 HVDC 100 km km km
06.03.12 49 WPP based on VSC HVDC VSC HVDC projects
06.03.12 50 WPP based on VSC HVDC BorWind 1
06.03.12 51 WPP based on VSC HVDC BorWind 1
06.03.12 52 WPP based on VSC HVDC BorWind 1 Off-shore station
• Topside weight approx 3200 t • Size approx 50 x 33,5 x 22 m • Jacket weight 1700 t • Height 62 m • Sea level to topside 20 m
06.03.12 53 WPP based on VSC HVDC BorWind 1 Off-shore station
06.03.12 54 WPP based on VSC HVDC BorWind 1 On-shore station
06.03.12 55 WPP based on VSC HVDC BorWind 1 On-shore station
06.03.12 56 WPP based on VSC HVDC Multiterminal HVDC Kriegers Flak
• Large off-shore wind farms on the way: • Germany: 50 MW and 288 MW • Denmark: 600 MW • Sweden: to be decided • Using the Off-shore wind farms cables for: • Grid connection of the OWF • Electricity trade • Secuirty of supply • Benefits: • Imppyroved economic efficiency • Improved electricity market • Improved security of supply • Demonstration of new technologies • Stepping stone for North Sea
06.03.12 57 Outline
• Seer presentation
• Wind power plants
• PV pppower plants
• Ongoing PhD research projects
• Conclusions
06.03.12 58 Solar Power Foreseen electricity production scenario by 2050
• PV will exppypgerience a very important growth in the next decades • CSP however, will be able to reduce or even replace conventional power plant capacities in covering base-load • Gas-driven peak-load power plants with low capacity will be maintained until 2050 • Conventional base-load power stations will disappear almost entirely
06.03.12 59 PV Power Capacity Global PV power capacity
Cumulative installed capacity from 2000 to 2015 . Source: “Global Market Outlook for Photovoltaics until 2015”, EPIA May 2011 • Almost 16.6 GWp installed in 2010 with global cumulative up to 40 GW (1/5 of WP) • Forecast 131 - 196 GW by 2015 (2 scenarios) • The EU is now the leader in terms of market and total capacity - thanks largely to German • The cost of solar electricity dropped to 15 Eurocent/KWh • The average efficiency – 19.5% in 2010 (SiC) with a target of 23% in 2020
06.03.12 60 Solar Power Vision 20xx -The 100 % Renewable Scenario
• “The European Supergrid” • Paralell DC backbone grid • A perfect application of HVDC • Open research topics • DC grid protection systems • Coordinated control of DC converters • Multiterminal HVDC classic challenging
06.03.12 61 Photovoltaic Power Characteristics • Static generation (complexities are at microstructure level) • Modular nature (from mW to MW) • Noise and pollution free • Reliable, long life (>20 year) • Simple installation • Building integration (onsite generation) • Large plant in dessert areas (lower visual impact) • Low operation cost • AbdtAbundant resource (Si)
06.03.12 62 PV Systems Stand-alone PV systems
Solar lighting in Mexico PV/Wind in Korea
Solar/FC Source: IdaTech
Mobile Solar. Source: Nasa
Source: Helios
06.03.12 63 PV Systems Grid-connected PV systems PV Buildings. Source BCIT , Burnaby, British Columbia
Residential, integrated roof
Power plants The Sarnia Solar Project in the Canadian state of Ontario
06.03.12 64 PV Cells Technology Main PV cell technologies
Monocrystalline Silicon Polycrystalline Silicon Amorphous silicon Thin film • Efficiency: 12 – 20 % • Efficiency: 10 – 17 % • Efficiency: 4 – 9 % • Amorphous Si, • Shape: round / • Shape: quadratic • Shape: slim ribbons cadmium telluride, quadratic • Colour: blueish, • Colour: black / dark copper idiindium • Colour: black / dark- shimmer brown diselenide and many blue / blueish • Peak power, app.: new others! • Peak power app.: 120 2 • Peak power, app.: 100 W/m 2 • Efficiency up to 12 % Wp/m2 50 Wp/m • Price app . 3-4 €/Wp • Can be deposited on • Price app. 4-5 € /Wp • Price app. 5-6 €/Wp any surface (continuously • can be foldable decreasing by ca 7% • Colour depends on p.a.) materials • CanbeclearfilmsCan be clear films mounted on windows or roof tiles
06.03.12 65 Concentrated PV Systems
• Sun light concentrated with lenses or Source: Amonix optical concentrators up to x500 typ. with tracking • High efficieny/high temp silicon solar cells or advanced III-IV multi-junction technology (~40% eff) • Considerable lower solar cell material • Potential lower overall cost than PV • 200-500 kWe -commercial,MW plants - near term • Fresnell lenses concentrator with tracking • Dish technology • 25 kWp unit/850W/m2 • Two-axis tr 06.03.12 66 PV Inverter Directly convert the dc power from solar panels to grid synchronized power Typical requirements: • “Very” high efficiency typ. > 95% (large variety of innovative topologies!) • “Very accurate” Maximum Power Point Tracking MPPT (typ. >99% eff.) • Grid connection standard requirements (apply to certain countries) . High performance grid monitoring and synchronization . Active Anti‐islanding algorithms . Isolation, leakage current monitoring, and dc current injection monitoring . High power quality (low current THD) Typically IGBT/MOSFETS and DSP technologies are used 06.03.12 67 PV Inverter PV inverters configuration Central inverters String (Multi)inverters Module inverters • 10 kW-1000kW, three- • 1.5 - 5 kW, typical residential • 50-180W, each panel phase, several strings in application has its own inverter parallel • each string has its own enabling optimal MPPT • high efficiency, low inverter enabling better MPPT • lower efficiency, cost, low reliability, not • the strings can have different difficult maintenance optimal MPPT orientations • highercost/kWp •Used for power plants •Three-ph ase inve etesorters for • also used in medium / power < 5kW high power PV systems (high efficiency) 06.03.12 68 PV Inverter Transformerless PV inverters Parasitic capacitance of the PV array Frame • PV array has large surface • Parasitic capacitance formed between grounded frame and PV cells Glass CG-PV • Its value depends on the: CG-PV I . Surface of the PV array and grounded frame G-PV PV-cell C . Distance of PV cell to the module G-PV Substrate . Atmospheric conditions and dust which can increase the electrical conductivity of the panel’s surface LkLeakage current • Charging and discharging this capacitance leads to ground leakage currents (unsafe for human interaction; damage PV panels) IG-PV IG-PV • Amplitude of leakage current depends on . Value of parasitic capacitance PV Array . Amplitude and frequency of imposed voltage Filter • RCM (Residual Current Monitoring) unit for monitoring CG-PV leakage ground currents IG-PV 06.03.12 69 PV Inverter Central inverters • High Performance for Large PV Plant, High Level Monitoring , High Level Intelligence, Reliability • High Efficiency (higher than 98%), Competitive prize/performance ratio • Advanced grid management functions: –LVRT – Frequency-dependent control of active power – Static voltage support based on reactive power – Dynamic Grid Support – Remote controlled power reduction in case of grid overload 06.03.12 70 PV Inverter Control structure of PV inverters PWM Vdc PWM X filter I pv I grid Vpv Vgrid Operarional control fromthe PVPP Basic functions – common for all grid-connected inverters • Grid current control . THD limits imposed by standards . Stability in case of grid impedance variations •DC voltage control . Adaptation to grid voltage variations . Ride-through grid voltage disturbances (optional yet) • Grid synchronization . Required for grid connection or re-connection after trip. 06.03.12 71 PV Inverter Control structure of PV inverters PWM Vdc PWM X filter I pv I grid Vpv Vgrid Operarional control fromthe PVPP PV specific functions – common for PV inverters • Maximum Power Point Tracking – MPPT • Plant Monitoring . Very high MPPT efficiency in steady state (typical > 99%) . Diagnostic of PV panel array . Fast tracking during rapid irradiation changes (dynamical MPPT efficiency) . Partial shading detection . Stable operation at very low irradiation levels • Sun Tracking (mechanical MPPT) • Anti-Islanding – AI as required by standards (VDE0126, IEEE1574, etc) . 1-2 axis motion controller • Grid Monitoring Tracking of Sun . Operation at unity power factor as required by standards . Fast Voltage/frequency detection 06.03.12 72 PV Inverter Control structure of PV inverters PWM Vdc PWM X filter I pv I grid Vpv Vgrid Operarional control fromthe PVPP Ancillary Support • Fault‐ride thhhrough • Reactive power strategies available to the TSO • Grid Voltage and Frequency Support • Power oscillation damping and • Power Quality . Harmonics, unbalance 06.03.12 73 Grid Requirements for PV Systems Anti-islanding • Islanding for grid connected PV systems takes place when the PV inverter does not disconnect after the grid is tripped, i.e. it is continuing to operate with local load. • If the PV inverter does not disconnect the following consequences can occur: • Retripping the line or connected equipment damaging due to of out-of-phlhase closure • Safety hazard for utility line workers that assume de- energized lines during islanding • In order to avoid these serious consequences safety measures called anti-islanding (AI) requirements have been issued and embodied in standards. 06.03.12 74 Grid Requirements for PV Systems Transient operation • Fault‐induced symmetrical and asymmetrical voltage dips must not lead to disconnection from the grid above given voltage‐time borderlines • Voltage support during network faults through reactive current feed‐in Normal operation Normal operation Should not disconnect Minimum Ir requirement for 3 phase fault MinimumI requirement for 1and 2 phase faults May disconnect with resynchronization within 2sec E.ON r May disconnect upon agreement I[p.u.]r EON. May disconnect by automatic protection relays 1.0 START FAULT END OF RECOVERY 0.8 V[%] 0.6 120 0.4 100 0.2 80 0 020.2 040.4 060.6 080.8 110.0 112.2 131.3 V[p. u. ] 60 0.2 40 0.4 0.6 20 0.8 0 01. 015. 070. 0 1.5 15 Time [sec.] 1.0 06.03.12 75 Grid Requirements for PV Systems Maximum allowable PV capacity Voltage limitations from network standards impacts PV penetration in LV networks Limitation 1 Limitation 2 •Voltage rise is the main constraint on connection of more PV plants • Both voltage limitations must be fulfilled at the same time 06.03.12 76 Grid Requirements for PV Systems Solutions for increasing maximum allowable PV capacity 1. Adapting tap positions of OLTC transformers 2. Network expansion (110/20kV) HV/MV Transmission OLTC MV/0.4 kV MV/LV Adding new line for PVs Tap position SbSubstat ion Existing feeder only with controller consumers Voltage measurements at critical points 3. Output power curtailment by PVs 4. Reactive power control by PVs 5. PV + storage system V [pu] P 1.1 P Q inverter P’ during PCC voltage > Distance 1.1pu PV 06.03.12 77 PV Power Plant Scheme Scheme based on multistring inverters 06.03.12 78 Some large PVPP Location: Haimhausen, Germany Nominal power: 1.12MWp PV modules: 6912 x 162Wp, polycrystalline Inverters: 1, central Tilt angle: 30o (from: http://www.phoenixsolar.com) Diversity: number & types of the PV modules Location: Rickelshausen, Germany Nominal power: 1.124MWp PV modules: 16524 x 67Wp & 70Wp, thin‐film Inverters: 2, central Tilt angle: 30o (from: http://www.phoenixsolar.com) 06.03.12 79 Some large PVPP Location: Yolo County, California Nominal power: 386.4kWp Sun‐trackers: 30, two‐axis PV modules: 1680 Inverter: 1 (from: http://www.advanced‐energy.com) Diversity: number & types of the sun‐trackers Location: Mühlhausen, Germany Nominal power: 6.28 MWp Sun‐trackers: 42, horizontal‐axis PV modules: 36000 Inverters: 17 (from: http://www.coplan‐online.de) 06.03.12 80 Some large PVPP Location: La Solana, Spain Nominal power: 6.53MWp PV modules: 40320 x 162Wp Inverters: 60, central (from: http://www.phoenixsolar.com) Diversity: number & types of the DC/AC inverters Location: Murcia, Spain Nominal power: 5MWp PV modules: 72488 x 67Wp & 70Wp Inverters: 375, mini central (from: http://www.gehrlicher.com) 06.03.12 81 Some large PVPP Size: 38.000 m2 Power: 1.5MWp Energy: 1.7 mill kWh/year (~600 households) CO2 avoided: 1200 t / year Modules: Thinfilm Unisolar Mounting: Roof top Inverters: TLX 10kW (150 pcs.) Installation Date: 2009 Location: Fiera de Roma 06.03.12 82 Benchmarking SihltiitktSpanish electricity market EPS Management Market structure & load evolution Spanish electricity markets configuration Matching demand evolution 06.03.12 83 Energy storage in PVPP AlitiApplications and usef flulness Energy MtfRESManagement from RES Different control strategies to manage the RES intermittent production can be introduced. Considering the increasing amount of energy capacity required: • Short‐term – Smoothening (or production leveling) and regulation • Mid‐term – Predictability Improvement, Production Shifting, Peak Shaving and Load Following. • Long‐term Load Leveling, Unit Commitment and Seasonal Storage ion tion tt cc Produ Produc PV PV 06.03.12 84 Energy storage technologies CiComparison Efficiency vs. lifetime State of development Energy cost vs. vs. nominal power power cost (min) Time Capital cost per cycle 06.03.12 85 Control strategies for PV+ES power plants PV+ES power p lant mod el Pref Ppv PES Short term – fluctuations reduction strategy Mid‐term – constant power steps strategy 06.03.12 86 Outline • Seer presentation • Wind power plants • PV pppower plants • Ongoing PhD research projects • Conclusions 06.03.12 87 Conclusions • Larger and larger WT (foundation, mooring, structures,…) • Direct drive WT • MV full-power converters • Off-shWPPhore WPP • Multi-terminal HVDC • HV MMC • Gird support and reinforcement • Extension of the Super-Grid: Solar Power in the Sunbelt • Large PVPPs • Development of new PV cells (thin-films, crystalline silicium,…) • HCPV • Centralized and modular power converters • New grid services for PV • Energy storage 06.03.12 88 Books Grid Converters for Photovoltaic and Power Conversion and Control of Wind Power Systems Wind Energy Systems ISBN-10: 0-470-05751-3, IEEE - ISBN-10: 0-470-59365-3, IEEE - Wiley – published January 2011 Wiley – published July 2011 06.03.12 89 Thanks for your attention Pedro Rodriguez [email protected]