DOCSLIB.ORG

Concentrating Solar Power Impact on Grid Reliability Nicholas W

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Concentrating Solar Power Impact on Grid Reliability Nicholas W Concentrating Solar Power Impact on Grid Reliability Nicholas W. Miller and Slobodan Pajic GE Energy Consulting Kara Clark National Renewable Energy Laboratory NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Technical Report NREL/TP-5D00-70781 August 2018 Contract No. DE-AC36-08GO28308 Concentrating Solar Power Impact on Grid Reliability Nicholas W. Miller and Slobodan Pajic GE Energy Consulting Kara Clark National Renewable Energy Laboratory Prepared under Task No. SETP.10304.23.01.10 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. National Renewable Energy Laboratory Technical Report 15013 Denver West Parkway NREL/TP-5D00-70781 Golden, CO 80401 August 2018 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 NOTICE This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. U.S. Department of Energy (DOE) reports produced after 1991 and a growing number of pre-1991 documents are available free via www.OSTI.gov. Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795. NREL prints on paper that contains recycled content. Acknowledgments This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The National Renewable Energy Laboratory and General Electric also thank the members of the technical review committee for their insightful comments and assistance. Participation in the committee does not imply agreement with the project findings. The committee included: • Mark Ahlstrom, WindLogics • Erik Ela, Electric Power Research Institute • Bradley Albert, APS • Tassos Golnas, U.S. Department of • William Anderson, Xcel Energy Energy • Jamie Austin, PacifiCorp • Irena Green, California Independent • Ron Belval, Tucson Electric Power System Operator • Ray Byrne, Sandia National • Rebecca Johnson, Western Area Laboratories Power Administration • Thomas Carr, Western Governors’ • Debra Lew, General Electric Association • Eddy Lim, Federal Energy • Kemal Celik, U.S. Department of Regulatory Commission Energy • Clyde Loutan, California • Malati Chaudhary, Public Service Independent System Operator Company of New Mexico • Kate Maracas, Western Grid Group • Bob Cummings, North American • Mark O’Malley, University College Electric Reliability Corporation Dublin • Donald Davies, Western Electricity • Brian Parsons, Independent Coordinating Council consultant • Joe Desmond, BrightSource • Henry Price, Independent consultant • Charles Diep, SolarReserve • Vikas Singhvi, Electric Power • Tom Duane, Public Service Research Institute Company of New Mexico • Charlie Smith, Utility Variable • Bob Easton, WAPA Generation Integration Group • Sara Eftekharnejad, Tucson Electric • Guohui Yuan, U.S. Department of Power Energy The National Renewable Energy Laboratory regrets any inadvertent omission of project participants and contributors. iii This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Executive Summary This study examines the impact of concentrating solar power (CSP) on grid reliability by investigating the dynamic behavior of the Western Interconnection under conditions of high solar and wind generation. Reliability in this case refers to the somewhat narrow context of stability: transient stability and frequency response; and control stability, especially that associated with weak grids. The objectives of this study were to identify renewable energy penetration levels and mixes, severe disturbances, and load conditions where grid performance and reliability could be enhanced with CSP plants. Instantaneous penetrations of wind and solar—both photovoltaics (PV) and CSP—up to approximately 60% were considered. The focus is on situations in the Western Interconnection bulk power system during which variable renewable generation has displaced other (non-CSP) synchronous thermal generation under highly stressed, weak system conditions. Particular attention was given to impacts of frequency-responsive controls and synchronous generation characteristics. This is relatively new ground for the industry, and this investigation is not a substitute for detailed planning, but the risks illustrated can be analyzed and mitigated. Tools, data, and the current state-of-the-art interconnection and bulk power system stability studies, if used following good system engineering practices as systems are built out, will ensure continued reliability of power systems. Key Findings Grid Build-Out to Support Added Solar and Wind Changes Transient Stability Transmission added in solar-rich areas to avoid thermal and voltage violations, plus changes in dispatch and commitment (Section 2), have some effect on transient stability. The impacts are mixed, with some improvements and decreases (Section 5.2). No stability violations— noncompliance with Western Electricity Coordinating Council (WECC) criteria—were found for the primary fault-clearing cases tested (Section 5.2 and Section 10.2). As noted, good planning practice needs to be observed. WECC-wide system inertia dropped up to 27%–32% from earlier light load planning cases. The earlier cases had less wind and solar generation and included synchronous generation, which was retired in the final study cases (Section 4.1). The lower system inertia did not present any significant stability or frequency response challenges. We did not observe systemic issues related to frequency and transient stability resulting from the solar and wind build-out. That is, the overall behavior was similar in character to the present system. The system seems to better tolerate non design-basis north-south separation with the grid additions (Section 6.6). For the conditions studied, a simultaneous nonsynchronous penetration (SNSP) of approximately 70% (Section 4.3) did not have an adverse impact on system-wide transient stability (Section 5.2). Transient stability issues seemed to be rather localized (Section 10.2). iv This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Primary Frequency Response from Concentrating Solar Power Helps Meet Frequency Response Obligation Because CSP uses a conventional synchronous steam turbine generator system to produce electricity, it always contributes inertia when running. Further, depending on the design and operation of the plant, it can provide primary frequency response (PFR) via governor action. It is by no means ensured that CSP plants will necessarily provide this service. Steam systems and turbines must be designed with this capability in mind for best economy. This report provides some discussion and concepts for possibly squeezing additional frequency response out of steam systems (Section 8.1). The discussion includes the concept of a triggered, open-loop control based on the accepted practice of fast-valving special protective systems (Section 8.3). PFR from CSP benefits frequency response, improves the system nadir, and helps the system (and regions thereof, such as California) meet their frequency response obligations (FRO) (Section 9.3). The contribution of synchronous inertia is observable, but it not very important for the conditions and cases examined. Tripping two of the Palo Verde Nuclear Generating Station units, for a loss of approximately 2,750 MW, is the design basis frequency event for WECC (Section 6.1.2). We have continued to use that event extensively in this study. Figure ES-1 shows three cases for that event run on the lighter load case (60% instantaneous wind and solar penetration for the U.S. WECC) that illustrate two separate points. The red trace shows the reference lighter load case. The CSP units are online contributing inertia, but there is no governor response. The blue trace shows the impact of enabling the governors on the CSP plants (per the model discussion in Section 3.2). As expected, both the frequency nadir and the settling frequency
Load more

Recommended publications
  • Electrical Limiting Factors for Wind Energy Installations
    Electrical limiting factors for wind energy installations Stefan Lundberg ISSN 1401-6184 Institutionen för elteknik Examensarbete 50E Göteborg, Sweden 2000 Abstract In this thesis the electrical limiting factors for installation of wind turbines stated by the Swedish connecting requirements, AMP, have been used to determine which types of power quality problems that will dominate when fix-speed wind turbines are installed. The main limiting factors are static voltage level influence and the flicker emissions. The investigation is based on field measurements on a stall-regulated and on a pitch-regulated wind turbine. It is found that the limiting factor from the power quality point of view is the flicker emissions if one turbine is installed. If three or more turbines are installed it is the static voltage variations that sets the limit, if the summation formula from AMP is used. It is found that the XR-ratio of the grid plays a very large influence on the installation possibility, and a ratio of 1.3-2.8 is the most favourable, depending on the short circuit ratio. The results shown in this thesis can be used to determine if there will be any problem with the static voltage level or the flicker emissions when stall-regulated wind turbines are connected to the network. I II Acknowledgements This work was performed July 2000 – December 2000 at the department of electric Power Engineering at Chalmers University of Technology, Gothenburg. I would like to thank my supervisor Torbjörn Thiringer at Chalmers University of Technology for this valuable advice, linguistic help, support and discussion throughout the work.
    [Show full text]
  • Influencing Factor Analysis of the Short Circuit Ratio on Grid-Connected Photovoltaic Systems 685
    RESEARCH Revista Mexicana de F´ısica 65 (6) 684–689 NOVEMBER-DECEMBER 2019 Influencing factor analysis of the short circuit ratio on grid-connected photovoltaic systems G. Hachemia, R. Dehinia, and F. Brahimb aElectrical Engineering Department; Tahri Mohammed University, B.P. 417, 08000 Bechar, Algeria, e-mail: [email protected] bUniversity Centre of Abdelhafid Boussouf-mila Received 22 September 2018; accepted 11 April 2019 Over the past few years, solar energy conversion technology is sharply developing. An important first step is to make this conversion system more effective and more reliable. The main objective of this paper is to study the influence of the power of the electricity network on the connection of the solar energy source. The photovoltaic source has been examined under the effect of the variation of the parameters of the networks such as the power of short-circuit and the frequency. The results obtained by the simulation have shown that the photovoltaic source has amazing performance if the power system is of high or medium power and with constant parameters. Keywords: Photovoltaic (PV) systems; short circuit power; network impedance. the active power; the reactive power. PACS: 42.79.Wc DOI: https://doi.org/10.31349/RevMexFis.65.684 1. Introduction production of the Photovoltaic installation, the extra charge is provided by the network. Otherwise, energy is supplied to Renewable energies generate little or no waste or polluting the public grid and is used to power consumers. In the past, emissions [1]. They contribute to the fight against the green- distribution networks have behaved like passive elements in house effect and CO2 emissions into the atmosphere, facil- which power flows unidirectional from the source station to itate the reasoned management of local resources, and gen- the end consumers.
    [Show full text]
  • Eagle Eye Will Continue to Accept Donations Through the End of the Year
    Fall 2015 Eagle Eye Institute Using the power of nature to transform urban youth. TM Summer 2015 Highlights! Eagle Eye had a busy summer engaging youth in Learn About programs, urban stewardship projects, and gardening activities. Tufts University Tisch Summer Fellow, Michelle Mu, and Northeastern Co-op Intern, Kristina Ferrara, joined Program Director, Susan Ekstrom, for a summer of learning, exploration, and fun with five youth organizations from Boston, Somerville, Medford, and Quincy. Learn About Forests and youth worker, Arthur Grupee, Boys and Girls Club. Youth joined us at Powisset for a day of enjoyed exploring the winding In early July, we were joined by hiking, catching butterflies and trails at Ravenswood while retired science teacher and moths, and harvesting potatoes. learning about animal naturalist, Charlie Saulnier, Arthur was very impressed with camouflage, hugging trees, and along with Somerville High the youth’s interest in the harvest holding a pickerel frog. Eagle School students from the Mystic and noted, “"this is the first time Eye staff members and Trustees Mural project to explore the I've seen them so willing to get Educator, Catherine Shortliffe, Middlesex Fells. In the morning their hands into [the soil] without were impressed with all youth the group walked along Spot any hesitation.” participants during our closing circle as they listed every tree we Pond and identified many native Arnold Arboretum Visit trees and wildflowers growing learned during our hike! along the banks of the pond. With our second Boston After lunch we ventured to the Urban Stewardship Chinatown Neighborhood group Virginia Wood section of the based out of Quincy we visited the Many Eagle Eye participants also Fells for a nature scavenger hunt Arnold Arboretum for a day full had a chance to give back to their led by Michelle and Kristina.
    [Show full text]
  • Standards/Manuals/ Guidelines for Small Hydro Development
    STANDARDS/MANUALS/ GUIDELINES FOR SMALL HYDRO DEVELOPMENT Electro-Mechanical– 3.2 Selection of Generators and Excitation Systems Sponsor: Lead Organization: Ministry of New and Renewable Energy Alternate Hydro Energy Centre Govt. of India Indian Institute of Technology Roorkee July 2012 Contact: Dr Arun Kumar Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Roorkee - 247 667, Uttarakhand, India Phone : Off.(+91 1332) 285821, 285167 Fax : (+91 1332) 273517, 273560 E-mail : [email protected], [email protected] DISCLAIMER The data, information, drawings, charts used in this standard/manual/guideline has been drawn and also obtained from different sources. Every care has been taken to ensure that the data is correct, consistent and complete as far as possible. 3.2 The constraints of time and resources available to this nature of assignment, however do not preclude the possibility of errors, omissions etc. in the data and consequently in the report preparation. Use of the contents of this standard/manual/guideline is voluntarily and can be used freely with the request that a reference may be made as follows: AHEC-IITR, “3.1 Electro-Mechanical– Selection of Turbine and Governing System for Hydroelectric Projects”, standard/manual/guideline with support from Ministry of New and Renewable Energy, Roorkee, June 2012. PREAMBLE There is a series of standards, guidelines and manuals available on electrical, electro-mechanical aspect of moving machines and hydro power related issues by Bureau of Indian Standards (BIS), Rural Electrification Corporation Ltd (REC), Central Electricity Authority (CEA), Central Board of Irrigation & Power (CBIP), International Electromechanical Commission (IEC), International Electrical and Electronics Engineers (IEEE), American Society of Mechanical Engineers (ASME) and others.
    [Show full text]
  • Based Resources Into Low Short Circuit Strength Systems Reliability Guideline
    Integrating Inverter- Based Resources into Low Short Circuit Strength Systems Reliability Guideline December 2017 NERC | Report Title | Report Date I Table of Contents Preface ...................................................................................................................................................................... iv Preamble .................................................................................................................................................................... v Acknowledgements ................................................................................................................................................... vi Executive Summary .................................................................................................................................................. vii Introduction .............................................................................................................................................................. ix Qualitative Description of System Strength ........................................................................................................... x Variable Energy Resources ..................................................................................................................................... x Wind Turbine Generator Technologies ............................................................................................................. xi Solar Photovoltaic Generator Technologies ...................................................................................................
    [Show full text]
  • Solar Thermal – Concentrated Solar Power
    Potential for Renewable Energy in the San Diego Region August 2005 Appendix E: Solar Thermal – Concentrated Solar Power This appendix was prepared by the National Renewable Energy Laboratory and is included in this report with their permission. The figure and chart numbers have been changed to be consistent with the number system of this report. NREL Report - Concentrating Solar Power (CSP) Central Station Solar Concentrating Solar Power Southern California is potentially the best location in the world for the development of large- scale solar power plants. The Mojave Desert and Imperial Valley have some of the best solar resources in the world. The correlation between electric energy demand and solar output is strong during the summer months when peak power demand occurs. This region is unique for the proximity of such an excellent solar resource to a highly populated residential and commercial region. Furthermore, the extensive AC and DC transmission network running through the region enables solar electric generation to be distributed to major load centers throughout the state. As a result of these factors and state and utility policy, the world’s largest and most successful solar electric power facilities are sited in Southern California and sell power to Southern California Edison (SCE). Concentrating Solar Power Technologies Concentrating solar power (CSP) technologies, sometimes referred to as solar thermal electric technologies, have been developed for power generation applications. Historically, the focus has been on the development of cost-effective solar technologies for large (100 MWe or greater) central power plant applications. The U.S. Department of Energy’s (DOE) Solar R&D program focuses on the development of technologies suitable for meeting the power requirements of utilities in the southwestern United States.
    [Show full text]
  • Incorporating Renewables Into the Electric Grid: Expanding Opportunities for Smart Markets and Energy Storage
    INCORPORATING RENEWABLES INTO THE ELECTRIC GRID: EXPANDING OPPORTUNITIES FOR SMART MARKETS AND ENERGY STORAGE June 2016 Contents Executive Summary ....................................................................................................................................... 2 Introduction .................................................................................................................................................. 5 I. Technical and Economic Considerations in Renewable Integration .......................................................... 7 Characteristics of a Grid with High Levels of Variable Energy Resources ................................................. 7 Technical Feasibility and Cost of Integration .......................................................................................... 12 II. Evidence on the Cost of Integrating Variable Renewable Generation ................................................... 15 Current and Historical Ancillary Service Costs ........................................................................................ 15 Model Estimates of the Cost of Renewable Integration ......................................................................... 17 Evidence from Ancillary Service Markets................................................................................................ 18 Effect of variable generation on expected day-ahead regulation mileage......................................... 19 Effect of variable generation on actual regulation mileage ..............................................................
    [Show full text]
  • Author's Personal Copy
    Author's personal copy Provided for non-commercial research and educational use. Not for reproduction, distribution or commercial use. This article was originally published in Evolution of Nervous Systems, Second Edition, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution's administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier’s permissions site at: http://www.elsevier.com/locate/permissionusematerial From Moore, B.A., Tyrrell, L.P., Kamilar, J.M., Collin, S.P., Dominy, N.J., Hall, M.I., Heesy, C.P., Lisney, T.J., Loew, E.R., Moritz, G.L., Nava, S.S., Warrant, E., Yopak, K.E., Fernández-Juricic, E., 2017. Structure and Function of Regional Specializations in the Vertebrate Retina. In: Kaas, J (ed.), Evolution of Nervous Systems 2e. vol. 1, pp. 351–372. Oxford: Elsevier. ISBN: 9780128040423 Copyright © 2017 Elsevier Inc. All rights reserved. Academic Press Author's personal copy 1.19 Structure and Function of Regional Specializations in the Vertebrate Retina BA Moore and LP Tyrrell,
    [Show full text]
  • IEEE Northern Canada & Southern Alberta Sections, PES/IAS Joint Chapter Technical Seminar Series
    IEEE Northern Canada & Southern Alberta Sections, PES/IAS Joint Chapter Technical Seminar Series Designing Electrical Systems for On-Site Power Generation Apr 04th/05th, 2016, Calgary/Edmonton, Alberta, Canada Author: Rich Scroggins, Technical Advisor, Application Engineering Group, Cummins Power Generation Electrical Systems for Onsite Power Generation Systems . Proper generator sizing for motor loads accounting for locked rotor kVA – in “across the line” motor starting applications. – in VFD motor starting applications. Generator short circuit characteristics and their effects on arc flash incident energy. Grounding (system and/or equipment) and ground fault detection of on- site power generation systems: – When to switch the neutral in emergency standby systems – Grounding and ground fault detection schemes for paralleled generator sets in both grid connected and islanded applications Contents . Generator Control Basics . Motor Starting Requirements . Non-Linear Loads and Harmonics . Generator short circuit characteristics . Arc Flash . Generator Grounding – Neutral Switching in Low Voltage Emergency Standby Systems – Grounding of paralleled Systems Basic Generator Set Controls HMI . GC: Genset Control GC – Engine Protection – Start/Stop – Operator Interface (Alarm/Metering) GOV ENGINE . GOV: Governor – Measure Speed/Control Fuel Rate AVR GEN . AVR: Automatic Voltage Regulation – Measure Voltage/Control Excitation CB kVAR= alternator POWER kW = engine TO LOAD Engines produce kW--Fuel Rate Controls Alternators make kVAR--Excitation Controls HMI Parallelling LOAD SHARE DATA GC Load Share Control – Communicates with the load share control on the GOV ENGINE other gensets Load – Adjusts governor set point to share kW equally Share SYNC AVR GEN – Adjusts AVR set point to share kVAR equally – Load share can be Isochronous or Droop CB POWER TO LOAD Sharing kW—Controlled by Fuel (Speed) Sharing kVAR– Controlled by Excitation (Voltage) Excitation System Considerations Self excited generators - Shunt .
    [Show full text]
  • The Integration of Solar Generation on a Power System: Operational and Economic Evaluation
    THE INTEGRATION OF SOLAR GENERATION ON A POWER SYSTEM: OPERATIONAL AND ECONOMIC EVALUATION by Marco Absalón Velástegui Andrade A Dissertation Submitted to the Faculty of Purdue University In Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy Department of Agricultural Economics West Lafayette, Indiana December 2018 ii THE PURDUE UNIVERSITY GRADUATE SCHOOL STATEMENT OF COMMITTEE APPROVAL Dr. Paul V. Preckel, Chair Department of Agricultural Economics Dr. Douglas J. Gotham State Utility Forecasting Group Dr. Andrew L. Liu School of Industrial Engineering Dr. Otto C. Doering Department of Agricultural Economics Approved by: Dr. Nicole O. Widmar Head of the Graduate Program iii A dedication to my dad in heaven and family. iv ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Paul Preckel for supporting and guiding me through this research process over the years. His mentorship and constant encouragement made this dissertation possible. I feel so grateful to have had him as my mentor and advisor. I would like to give a special thanks to the rest of my committee members. Dr. Douglas Gotham for his patience and expert advice; Dr. Andrew Liu and Dr. Otto Doering for their time and feedback that helped to improve my research. I am also thankful for my colleagues at the State Utility Forecasting Group (SUFG): Dr. David Nderitu, Mr. Timothy Phillips, Dr. Liwei Lu, Mrs. Fang Wu and Mrs. Darla Mize. Thank you all for your understanding and support provided through busy times. I would also like to thank Dr. Willian Hutzel from Purdue University and Mr. Larry Conrad from the Indianapolis Power & Light Company (IPL) for providing valuable data for this study.
    [Show full text]
  • The Private and Public Economics of Renewable Electricity Generation
    NBER WORKING PAPER SERIES THE PRIVATE AND PUBLIC ECONOMICS OF RENEWABLE ELECTRICITY GENERATION Severin Borenstein Working Paper 17695 http://www.nber.org/papers/w17695 NATIONAL BUREAU OF ECONOMIC RESEARCH 1050 Massachusetts Avenue Cambridge, MA 02138 December 2011 I am grateful to Judd Boomhower for excellent research assistance. I also benefited from the comments of David Autor, Duncan Callaway, Lucas Davis, Meredith Fowlie, Michael Greenstone, Bill Hogan, Chad Jones, Paul Joskow, Chris Knittel, John List, Karen Notsund, Richard Schmalensee, and Tim Taylor. This research was supported in part under a research contract from the California Energy Commission to the Energy Institute at Haas. The views expressed herein are those of the author and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peer- reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications. © 2011 by Severin Borenstein. All rights reserved. Short sections of text, not to exceed two paragraphs, may be quoted without explicit permission provided that full credit, including © notice, is given to the source. The Private and Public Economics of Renewable Electricity Generation Severin Borenstein NBER Working Paper No. 17695 December 2011 JEL No. L94,Q42,Q48 ABSTRACT Generating electricity from renewable sources is more expensive than conventional approaches, but reduces pollution externalities. Analyzing the tradeoff is much more challenging than often presumed, because the value of electricity is extremely dependent on the time and location at which it is produced, which is not very controllable with some renewables, such as wind and solar.
    [Show full text]
  • Minimum Short Circuit Ratio Requirement for MMC-HVDC Systems Based on Small-Signal Stability Analysis
    energies Article Minimum Short Circuit Ratio Requirement for MMC-HVDC Systems Based on Small-Signal Stability Analysis Zheren Zhang 1, Liang Xiao 2 , Guoteng Wang 1, Jian Yang 1 and Zheng Xu 1,* 1 College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China 2 China Southern Grid Power Dispatching and Control Center, Guangzhou, Guangdong 510700, China * Correspondence: [email protected]; Tel.: +86-0571-8795-2074 Received: 26 June 2019; Accepted: 18 August 2019; Published: 26 August 2019 Abstract: This paper determines the minimum short circuit ratio (SCR) requirement for a modular multilevel converter based high-voltage direct current (MMC-HVDC) transmission systems. Firstly, a simplified model of MMC is introduced; the MMC is represented by its AC and DC side equivalent circuit. Next, by linearizing the MMC subsystem and the DC network subsystem, the deduction of the small-signal models of MMC subsystem, the small-signal model of the DC network and MMC-HVDC are carried out successively. Thirdly, the procedure for determining the minimum SCR requirement of MMC-HVDC is described. Finally, case studies are performed on a two-terminal MMC-HVDC system under four typical control schemes. The results show that the restraint factors for the rectifier MMC is predominantly the voltage safety limit constraint, and the restraint factors for the inverter MMC are mainly the phase locked loop (PLL) or the outer reactive power controller. It is suggested that the minimum SCR requirement for the sending and the receiving systems should be 2.0 and 1.5 in the planning stage. Keywords: modular multilevel converter (MMC-HVDC); small signal stability; minimum SCR; control scheme 1.
    [Show full text]