Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
A CASE FOR MEDIUM VOLTAGE DIRECT CURRENT (MVDC) POWER FOR DISTRIBUTION APPLICATIONS IEEE-PES Power Systems y Conference and Exposition p Paper Session: Substation Innovations from Conventional Design March 23, 2011 – Phoenix, AZ Authors: D Gregory Dr. G Reed, R d Dr. D G George K Kusic i – University U i it off Pitt Pittsburgh b h Dr. Jan Svensson, Dr. Zhenyuan (John) Wang – ABB Inc., R&D Background, Motivation, and Introduction 2 A New Era of DC Power Systems • Corporate research centers, universities, and industry are beginning g g to (re)consider ( ) the premise p of DC power p in future transmission and distribution system applications. • Historically, AC has dominated the power industry • W Westinghouse, i h Tesla, T l Edison, Edi and d others h intensely i l fought f h the h initial i ii l ‘AC/DC Wars’ at the turn of 20th Century • AC proved superior for all the right reasons at the time • H However, we continue ti ttoday d to t depend d d on a ‘legacy’ ‘l ’ century-old t ld and d aging AC approach, concept, technology-base, and infrastructure • What has changed for DC in the 21st Century? • The era of Power Electronics Technologies • Continued improvements and efficiencies in semiconductors, devices, circuits, designs, systems, and applications scaled at all levels • Consumer devices, emerging resources, energy storage, and other systems operating at or supplying absolute DC power 3 DC Applications in Modern Society • Rapidly Emerging DC Applications in the 21st Century • Consumer Electronics • Devices and Equipment Operated at Low-Level DC (Res/Comm) • Renewable Energy Systems • Generation Systems Producing DC Output Power (e.g., (e g Solar) • Transportation Electrification • Electric Vehicles Powered by DC • Information Technology and the Internet • Enhancement of Energy Efficiency via DC (e.g., Data Centers) • Energy Storage Technologies • DC O Output and d Integration I i through h h DC Interconnections I i • Transmission and Distribution Infrastructure • High Voltage Direct Current (HVDC) Systems (i.e., Transmission) • What is Missing? • Medium Voltage DC (MVDC) Distribution Infrastructure 4 Medium Voltage DC Networks • MVDC Technology Development • Benefits for installations of large g and small scale wind / solar farms, and other forms of bulk and distributed generation; as well as for DC-loads, energy storage, EV integration, etc. • Efficiency is expected to increase due to minimized power conversions; but overall complexity may increase • New technical requirements, standards, protective devices, schemes, and other concepts require development / proof • R&D is necessary for evaluating the MVDC potential • High Voltage Direct Current (HVDC) Systems • Proven benefits and merit over high voltage AC transmission for long distance power delivery applications and recent offshore and other generation interconnections • MVDC, however, is not a simple scaling of voltage level • Focused research, development, and demonstration is needed 5 The MVDC Distribution Network Concept 6 Medium Voltage DC Network Concept Existing AC Infrastructure AC Transmission Supply FACTS Compensation Future HVDC Intertie Fuel Cells Non-Synchronous Generation(Wind) STATCOM / SVC DC DC DC DC HVDC System Photovoltaic Generation AC DC DC DC AC DC HVDC / MVDC DC DC DC DC DC DC DC DC Distribution DC Load Circuits DC DC DC AC DC AC Electric Vehicle Future DC Industrial Facility Future DC Data Centers DC AC Electronic and AC Loads Motor Distribution Level Sensitive Load Storage Variable Frequency Drives Control Algorithm 7 MVDC Network Applications • Development Program Applications • Renewable energy resource integration and end end-use use aspects: • Solar energy – distributed, remote • Wind energy – distributed, off-shore, remote • Fuel cell integration • Electric vehicle integration • Variable frequency drives supply • Sensitive S iti and d electronic l t i load l d supply l • Data centers – supply infrastructure • Power plants – internal plant distribution systems • Greenfield industrial parks • Energy storage interconnection and control • DC/AC power factor correction for distribution load circuits • Dynamic voltage and VAR optimization • High Voltage AC and DC transmission integration Preliminary Work Modeling, Simulation, and Analysis 9 Preliminary MVDC Development – Subsystem 1 + - 1.4 MW Supply Wind Turbine MOD 2 Type 575 V / 14 kV #1 #2 Six Pulse Graetz Bridge AC/DC Rectifier Three Level 20 kV / 460 V Neutral Point IM Clamp #1 #2 Multilevel Inverter 10 kW Bidirectional DC/DC Converter AC C Load n=5 GRID 69 kV / 14 kV #1 Transmission Five Level 20 kV / 460 V Neutral Point IM Clamp #1 #2 Multilevel I Inverter t 10 kW #2 69 kV 20 kV 10 Research Objectives – Subsystem 1 • Analysis conducted within the PSCAD simulation environment • Evaluating a uat g tthe e pe performance o a ce o of ttwo op practical act ca topo topologies og es o of multilevel inverters which include the neutral point clamp converter and flying capacitor circuitry. • PWM Techniques: Phase Disposition Disposition, Phase Opposition Disposition, and Alternate Phase Opposition Disposition • Total Harmonic Distortion: THD appears to be the best metric for g their performance. p evaluating • Dynamic Performance Evaluation of Network • Wind Speed Adjustments: Average wind speed will be modeled initially without ramp and fluctuation effects in the wind source. source • DC Bus and Motor Faults: Analyze the effects of capacitor balancing of the power electronic inverters and effects of motor torque and speeds. • Load Energizing: Impacts on THD distribution as certain loads are connected in and out of the circuitry. 11 Preliminary MVDC Development – Subsystem 2 60 0 [MVA] 60.0 230.0 [kV] / 20.0 [kV] #1 #2 MW MVAR 60.0 [[MVA]] 575 [V] / 20.0 [kV] #1 #2 12 MVAC System for Comparison – Subsystem 2 60.0 [MVA] 230 0 [kV] / 20 230.0 20.0 0 [kV] #1 #2 60.0 [MVA] 20.0 [kV] / 4.0 [kV] 60.0 [MVA] 5.0 [kV] / 20.0 [kV] #1 #1 #2 #2 MW MVAR 60.0 [[MVA]] 20.0 [kV] / 5.0 [kV] #1 #2 60.0 [MVA] 575 [V] / 20.0 [kV] #1 #2 13 Factors for Comparison of MVDC/AC – Subsystem 2 • Performance under the following conditions • Loss of Generation • i.e., PV Array is lost due to a fault, how does the system react and recover from this loss? • Dynamic Changes in Renewable Generation • Similar to “loss of generation” but generation is not completely lost lost, only its voltage and thus power are altered • Switch Misfiring • If the power electronics do not react in an ideal manner manner, how is voltage and power flow affected? Preliminary MVDC Development – Subsystem 3 15 Research Objectives – Subsystem 3 • DC Distribution for Future Industrial Facilities • Manufacturing/Industry • Direct DC Supply for VFDs, Industrial Automation and Electronics Equipment • Data Centers and IT • Direct DC Supply for Computer, UPS and Battery Systems, LED lighting • DC Bus Architecture • Easily incorporates on-site solar generation and hybrid electrical storage options Next Steps in MVDC Development • Program Objectives, Goals, and Future Vision • Complete the modeling, modeling analysis, analysis and verification of all subsystems of the MVDC concept • Integrate the various subsystems, resources, and loads into one model for full-scale full scale analysis • Development and integration of control concepts • Establish full verification of total system concepts, including operation and control • Model and test various improvements and enhancements for parameter evaluation (e.g., advanced semiconductor characteristics, optimized converter designs and control, etc.) • Scaled proto-type development and testing • Full scale deployment p y and demonstration • Application for retrofit or green-field facility/site as a complete DC-based network Summary 18 Summary • MVDC Technology Development Benefits • Improved efficiency for renewable energy integration • Support for the continued evolution of greater penetrations of DC-based loads and resources • Enhanced integration of energy storage systems and EVs • Advancements in optimization, design, and applications of high capacity power electronics converter technologies • Advanced semi-conductor device developments • Advanced smart grid methodology development for integrated resource/load energy management and control • Enhancement of existing interconnecting alternating current (AC) infrastructure p of additional HVDC delivery y infrastructure • Enabled development • Increased efficiency and lower operating losses in overall power system delivery, generation, and end-use applications Acknowledgments The Commonwealth of Pennsylvania – Dept. of Community and Economic Development, Ben Franklin Technology Development Authority University of Pittsburgh – Electric ect c Power o e Research esea c G Group oup Graduate G aduate Students: Stude ts Brandon Grainger, Matthew Korytowski, Emmanuel Taylor Q&A THANK YOU