1 development of distributed generation in China

电力毕业设计(论文) 题目智能电网关键技术的分析与探讨智能电网关键技术的分析与探讨摘要21世纪电力供应面临环境压力、购电能力、安全可靠和高效利用等重大挑战。

以美国和欧盟为代表的不同国家和组织不约而地提出要建设灵活、清洁、安全、经济、友好的智能电网，将智能电网视为未来电网的发展方向。

智能电网已成为近年来国内外有关未来电网发展趋势的热门话题。

文章简要分析了智能电网研究背景情况，智能电网的概念、特性以及国内外发展现状。

重点研究了智能数字变电站、分布式能源和可再生能源接入相关技术。

其中数字变电站部分首先分析研究了数字变电站的系统结构，主要研究了数字电流互感器的原理和特性及发展的新方向，然后设计了以罗氏线圈为电流传感头的数字采集系统。

分布式能源部分首先研究了分布式发电技术，包括太阳能发电技术和风能发电技术。

然后分析了几种储能技术，重点分析了超导储能和超级电容器储能技术的原理，接着分析了并网的问题和解决方法，最后对智能电网的发展前景进行了展望，并总结了其技术优势和存在的问题。

关键词：智能电网数字变电站分布式能源可再生能源微网THE ANALYSIS AND DISCUSSION OFSMART GRID’S KEY TECHNOLOGYAbstractIn the 21th century electricity supply is facing with great challenges such as environmental pressures, the capacity of electricity purchase ,safety ,reliability and efficient use.Different countries and organizations such as US and UE put forward to built a flexible clean safe economical power grid and make smart grid the future power grid’s direction. Smart grid has become a hot topic of the development trend of power grid at home and abroad .The paper briefly analyze the research background of smart grid its concept features and current development status. It focuses on the intelligent digital substation technology and the link technology distributed energy and renewable energy .The first part analyze and research the digital substation system’s architecture .It mainly research digital current transformer’s principle features and the new development direction .Then it designs a digital acquisition system which make Rogowiski circle as the current sending head. The second part studies distributed generation technology including soar power generation and wind power generation technology. Then it analyze several energy storage technologies focusing on the analysis of the super conducting energy storage and super capacitor energy storage principles . Then it discusses the problem and solution of linking to the power grid. Finally it draws the development of smart grid’ prospect and summarizes its technical advantages and problems.Key words: smart grid; digital substation; distributed energy resource; renewable energy resource; micro-network目录摘要 (I)Abstract (II)1绪论 (1)1.1 课题背景 (1)1.2 智能电网的概念及特性 (1)1.3 智能电网的发展现状 (2)1.3 1 国外研究现状 (2)1.3.2 国内研究进展 (3)2 数字变电站技术 (4)2.1 数字变电站概述 (4)2.2 IEC61850简介 (4)2.3 数字变电站的系统结构 (5)2.3.1 数字化的一次设备 (5)2.3.2网络化的二次设备 (10)2.4 数字变电站的信息采集 (11)2.4.1 总体设计 (12)2.4.2 系统硬件设计 (12)3 分布式能源的接入 (15)3.1 分布式能源的系统集成 (15)3.1.1 分布式发电 (15)3.1.2 储能技术 (16)3.2 可再生能源和分布式能源并网 (18)3.2.1 并网定义和并网意义 (18)3.2.2 并网带来的问题 (19)3.3 微网 (19)3.3.1 微网概述 (19)3.3.2 微网的运行与控制 (21)3.4 分布式能源的发展方向 (21)4智能电网的发展前景 (23)5 智能电网技术优劣势分析 (24)结束语 (26)参考文献 (27)致谢 (28)1绪论1.1 课题背景在20世纪，大电网作为工程领域的最大成就之一，体现了能源工业的战略布局，是实现各种一次能源转换成电力能源之后进行相互调剂、互为补充的迅速、灵活、高效和能源流通渠道。

微电网控制与保护学习心得摘要：本文介绍了文献查阅后总结的微电网的基本知识和微电网控制与保护相关的一些问题。

微电网的出现协调了大电网与分布式电源的矛盾，对大电网表现为单一的受控单元，对用户则表现为可定制的电源，可以提高本地供电可靠性，降低馈线损耗。

但是目前我国微电网的发展尚处于起步阶段，还有很多问题有待研究。

微电网的保护和控制问题是目前分布式发电供能系统广泛应用的主要技术瓶颈之一。

微电网的保护既要克服微电网接入对传统配电系统保护带来的影响，又要满足含微网配电系统对保护提出的新要求，这方面的研究是保证分布式发电供能系统可靠运行的关键。

文中提出了一些现有的文献中提及的微电网继电保护方法和保护方案。

关键词：微电网；控制；保护；分布式发电Abstracts：This article describes the literature review after the conclusion of the basics of micro grid and micro grid control and protection-related problems. The emergence of micro-coordination of a large power grid and distributed power conflicts, the performance of a single large power controlled unit, users can customize the performance of the power supply, can improve local supply reliability and reduce feeder loss. But at present, the development of micro-grid is still in its infancy, there are many problems to be studied. Microgrid protection and control of distributed power generation is widely used for energy systems one of the main technical bottlenecks. Microgrid protection is necessary to overcome the Microgrid access to protect the traditional distribution system impact, but also to meet with micro network distribution system to protect the new requirements, this research is to ensure that distributed generation energy supply system reliable operation of the key. This paper presents some of the existing literature mentioned methods and microgrid relay protection scheme.Key Words：Microgrid; Control; Protection; Distributed Power Generation一、微电网基本知识当前电力系统已成为集中发电、远距离高压输电的大型互联网络系统。

微网控制技术的研究进展摘要：随着分布式发电的发展，微电网的研究已经成为能源和电力领域的一个热点，运行控制是微网研究和应用的主要技术之一。

本文主要阐述了国内外微网的研究进展，微网并网和孤岛两种运行方式的控制策略，并分析了主要控制策略的研究进展，最后讨论了未来的研究重点，以便微网安全运行。

关键词：并网运行、孤岛运行、控制策略The research process of microgrid control technology Abatract：With the development of distributed generation, the research microgrid has become a hot topic in the field of energy and power, the operation control of microgrid is one of the main technologies in the study and application of microgrid. This paper mainly talks about the research process of microgrid in foregin and China, and the control strategies in the utility connected operation and the islanding operation. It also analysis the research process of the important control strategies, at last it discusses the research focus in the future, in order to make it operated safely. Key Words：connected operation, islanding operation, control strategy引言随着新能源的发展，分布式发电DG(distributed generation)日渐成为社会研究的热点。

The Encompassing Aspects of Smart CitiesIn the modern era, the concept of smart cities has gained immense popularity, as it offers a vision of afuture where technology and urban planning intersect to create sustainable, efficient, and liveable environments. Smart cities represent the integration of information and communication technologies (ICT) with urban infrastructure, services, and governance to enhance the quality of life for citizens and visitors alike. This integration encompasses various domains, including but not limited to the following. **1. Smart Governance:** Smart governance refers to the use of technology to improve the decision-making process, enhance transparency, and promote citizen engagement. It involves the digitization of government services, such as online permit applications, electronic payment systems, and data-driven policy decisions. Smart governance also ensures better coordination between different departments and agencies, leading to more efficient service delivery.**2. Smart Infrastructure:** Smart infrastructurerefers to the integration of technology into physical urban structures, such as roads, bridges, and buildings. Thisincludes the use of sensors and data analytics to monitor and manage infrastructure performance, predict maintenance needs, and optimize resource allocation. For instance, smart traffic systems can adjust traffic lights and routing based on real-time traffic data, reducing congestion and travel time.**3. Smart Energy:** Smart energy systems integrate renewable energy sources, smart meters, and demand-response management to enhance energy efficiency and sustainability. These systems allow for real-time monitoring and control of energy use, enabling citizens and businesses to make informed decisions about their energy consumption. Smart energy also facilitates the integration of distributed generation, such as solar panels and wind turbines, into the grid, promoting a more resilient and sustainable energy supply.**4. Smart Mobility:** Smart mobility solutions aim to improve transportation systems, reducing congestion, emissions, and travel time. This includes the use of technologies such as GPS tracking, public transportation optimization, and shared mobility options. Smart mobilityalso encourages the use of non-motorized modes of transportation, such as cycling and walking, through the provision of infrastructure and incentives.**5. Smart Environment:** Smart environment refers to the use of technology to monitor and protect the urban ecosystem. This involves the deployment of sensors to measure air quality, noise pollution, and other environmental factors. Smart environment solutions also include the use of green infrastructure, such as parks and green roofs, to enhance urban biodiversity and improve the urban microclimate.**6. Smart Safety and Security:** Smart safety and security systems utilize advanced technologies, such as surveillance cameras, sensors, and data analytics, to enhance public safety and security. These systems can detect and respond to emergencies quickly, reducing the risk of harm to citizens and property. Smart safety and security also promote the use of proactive measures, such as crime prevention and risk mitigation, to create safer cities.In conclusion, smart cities encompass a wide range of aspects, from smart governance and infrastructure to smart energy, mobility, environment, and safety and security. The integration of technology with urban planning and services is crucial for creating sustainable, efficient, andliveable cities that meet the needs of citizens andvisitors alike. As we move forward into the future, the development and implementation of smart city solutions will become increasingly important for fostering inclusive and resilient urban environments.**智慧城市涵盖的多个方面**在现代社会，智慧城市的概念备受瞩目，因为它描绘了一个技术与城市规划交织的未来，创造了可持续、高效且宜居的环境。

分布式发电技术研究综述作者：钱俊刘敏来源：《现代电子技术》2013年第13期摘要：简要概述了分布式发电的应用历程，详细介绍了分布式发电技术的相关研究进展情况，包括分布式电源并网技术以及分布式发电优化配置问题的研究现状。

并对分布式发电技术未来的发展方向与趋势进行了探讨，为其在电力系统中的广泛高效应用提供了参考。

关键词：分布式发电；并网；优化配置；电力系统中图分类号： TN710⁃34； TM61 文献标识码： A 文章编号： 1004⁃373X（2013）13⁃0167⁃04Overview of research progress on distributed generation technologyQIAN Jun， LIU Min（Jinggangshan Power Plant， Huaneng Power International， Inc.，Ji’an 343099， China）Abstract： The application history of distributed generation is briefly summarized， and the progress of its relevant technology research is introduced in detail， including the research status of distribute power grid connection technology and distributed generation optimal configuration. In order to provide reference for the application of distributed generation technology in power system widely and efficiency， the development trend of distributed generation technology is also discussed.Keywords： distributed generation； grid connection； optimal allocation； power system0 引言经济和社会的快速发展导致我国的能源消耗增长十分迅速，而大机组、大容量的集中规模化发电存在诸如无法灵活跟踪负载变化、不能对偏僻地区进行理想供电等缺点，作为目前电能生产的主要方式与电力用户对电能质量高要求之间的矛盾日益凸显[1]。

2020年第39卷第10期传感器与微系统(Transducer and Microsyslem Technologies)153｛应用技术'DOI：10.13873/J.1000-9787(2020)10-0153-04改进遗传算法在含DG配电网重构中的应用金亦舟，张莉萍，武鹏，牛启帆，沈依婷(上海工程技术大学电子电气工程学院，上海201620)摘要：计及分布式电源(DC)出力和负荷不确定性对配电网的影响,提岀一种适用于不确定性配电网重构的改进遗传算法。

首先，基于DG出力概率模型，给出考虑多种不确定性的供电能力机会约束模型，建立了考虑供电能力机会约束条件的配电网重构模型;然后，改进遗传算法中生成初始种群与交叉操作的方式,使其适用于所建配电网重构模型;最后，使用改进遗传算法求解配电网重构模型，给出基于蒙特卡罗模拟的随机机会约束检验方法。

IEEE33节点算例的计算结果表明，本文方法能计及DG出力和负荷的不确定性，所得方案可满足设定的供电能力，提升配电网重构方案的抗风险能力。

关键词：配电网重构；改进遗传算法；供电能力；分布式电源；机会约束规划中图分类号：TM727文献标识码：A文章编号：1000-9787(2020)10-0153-04Application of improved GA in distribution networkreconfiguration with DGJIN Yizhou,ZHANG Liping,WU Peng,NIU Qifan,SHEN Yiting(School of Electronic and Electrical Engineering,Shanghai University of Engineering Science,Shanghai201620,China) Abstract:The impact of distributed generation(DG)access on distribution network is taken into account,animproved genetic algorithm for uncertain distribution network reconfiguration is proposed・Firstly,based on DGoutput probability model,a power supply capability index opportunity constraint model considering uncertainty ispresented,and the distribution network reconfiguration model considering chance constrained condition isestablished；then, the initial population generation and crossover operation of genetic algorithm is improved to makeit suitable for the uncertain distribution network reconfiguration model.Finally,a simulation method for calculatingthe chance constrained of power supply capability index is presented.The33ode example shows that the methodis able to take the uncertainty of DG output and distribution network load into account on the basis of traditionalgenetic algorithm,The reconfiguration scheme can meet the index of power supply capability and improve the anti・risk capability of the reconfiguration scheme.Keywords:distribution network reconfiguration；improved genetic algorithm；power supply capability index；distributed generation(DG)；chance constrained programming0引言配电网重构是一种根据系统实时运行状况，通过优化网络拓扑来提高网架运行效率和电能质量的重要手段。

第46卷第9期电力系统保护与控制V ol.46 No.9 2018年5月1日Power System Protection and Control May 1, 2018 DOI: 10.7667/PSPC170578风储孤网系统运行与控制研究综述叶 鹏1，李 山1，何 淼1，王 刚2， 孙 峰2(1.沈阳工程学院电力学院，辽宁 沈阳 110136; 2.国网辽宁省电力有限公司电力科学研究院，辽宁沈阳110006)摘要：随着分布式发电的快速发展和应用，风储孤网系统的运行与控制技术越来越受到人们的重视。

与联网运行相比，风储孤网系统具有运行灵活、高效等特点，是未来新能源的重要应用形式和技术发展趋势。

综述了风储孤网系统运行与控制技术的最新进展，从风储孤网系统结构与应用、风储孤网系统的协调控制、自启动、能量管理和系统保护等方面进行了总结研究。

分析了风储孤网系统运行与控制的关键技术，给出了风储孤网系统自启动的实现方法和风储孤网系统能量管理系统的设计方案，并对风储孤网系统未来的技术发展趋势进行预测和展望。

关键词：风储孤网系统；运行与控制；自启动；能量管理；保护Review of operation and control of the wind storage isolated network systemYE Peng1, LI Shan1, HE Miao1, WANG Gang2, SUN Feng2(1. School of Electric Power, Shenyang Institute of Engineering, Shenyang 110136, China; 2.State Grid Liaoning Electric Power Research Institute, Shenyang 110006, China)Abstract: With the rapid development and application of distributed generation, more and more attention has been paid to the operation and control technology of the wind storage isolated network system. Compared with the interconnected network operation, the wind storage isolated network system has the characteristics of flexible operation and high efficiency. It is an important application form and technical development trend of the new energy resources in the future.The latest development of operation and control technology of the wind storage isolated network system is summarized.The structure and application, coordinated control, self start, energy management and system protection of the wind storage isolated network system are summarized. The key technologies of operation and control of the wind storage isolated network system are analyzed. The realization method of self starting and design scheme of energy management system of the wind storage isolation network system are given, and the future development trend of the wind storage isolation network system is forecasted and prospected.This work is supported by Natural Science Foundation of Liaoning Province (No. 201602534) and Shenyang Science and Technology Project (No. F16-205-1-08).Key words: wind storage isolated network system; operation and control; self starting; energy management; protection0 引言在分布式能源发电中，风力发电是技术最成熟、最具备开发条件、发展前景良好的项目。

Distributed Generation (DG) ManualDecember 3, 2020 (7th Edition)Revision 1.0December 3, 2020 Application for Interconnection of DG Page 46 of86Appendix DApplication for Interconnection of DGAPPLICATION FOR INTERCONNECTION OF DISTRIBUTEDGENERATION (DG Application)Must be completed for any size or type of DG1.All DG Owners must complete this Section regardless of size or typeDG Owner’s Name(s):__________________________________________________________DG Owner’s Mailing Address (specific including zip code):____________________________DG Site Address (include zip code):DG Owner’s Email Address: _____________________________________________________ Account Number (if applicable):Telephone (normal): (emergency):Information Prepared and Submitted By:Name:Address:Contact Number (24hrs. / 7days a wk.):______________________________________________ Email:Signature (required): Date:Name of DG Owner or DG Owner’s designated representative who can be contacted by CPS Energy at any time throughout ownership of DG system in case of emergency or important issues concerning the DG System.DG Owner or DG Owner’s designated representative(if not same as above):Contact Number (24hrs. / 7days a wk.):Email:Installer/Contractor (if not same as above):Contact Number (24hrs. / 7days a wk.):Email:The following information shall be supplied by the DG Owner or DG Owner’s designated representative and/or contractor. All applicable items must be accurately completed in order that the DG Owner’s generating facilities may be effectively evaluated by CPS ENERGY for interconnection.Is this DG System an upgrade to the existing DG System installed? Yes No Number of units/Configuration of modules:Module manufacturer:Type (Synchronous, Induction, Backup or Inverter):Fuel Source Type (Solar, Natural Gas, Wind, etc.):Kilowatt rating for this installation (95° F): kW ac Kilowatt rating for existing installation (95° F) (if applicable): kW ac Total aggregated Kilowatt Rating for DG installation (95° F): kW ac Kilovolt-Ampere Rating (95° F): kVA ac Power Factor:Voltage Rating: V ac Amperage Rating: A ac Frequency: Hz Number of Phases:If DG is a Grid-Tied system, amount expected to be exported to grid: kW acInstructions:For DG Systems with total capacity (including aggregate) less than 25 kW ac in a single parcel of property with single or multiple meters, complete section 2 and initial, sign, and date the last page of the application.For DG Systems with total capacity (including aggregate) of 25 kW ac and greater in a single parcel of property with single or multiple meters, or DG Systems of any size within the Downtown Network Area, complete sections 3 to 6 and initial, sign, and date the last page of the application.2.DG Systems with Total Capacity (Including Aggregate) Less Than 25 KW ac ina Single Parcel of Property with Single or Multiple MetersSubmit the following information:Detailed operational one-line diagramSite planMeter loop drawing (elevation view)/ Proposed Equipment Layout“Visible” disconnect device or breaker and include the following ratings as applicable: Full Load Rating, Momentary Rating, Interrupting ratingShow all protective devices and include as applicable size, rating, manufacturer, type, style, model, settingsNote: All drawings to scale – email in PDF format to****************Expected Start-up Date:Please describe the Normal Operation of Interconnection, provide operating procedure: (examples: provide power to meet base load, demand management, standby, back-up, other)Also, will the DG parallel continuously with CPS Energy? If only paralleling momentarily, forIf the type is not an Inverter, provide RMS Symmetrical Short Circuit Current and X/R Ratio at Rated Voltage at point of common coupling for:Line-to Ground Fault: X/R:3-Phase Fault: X/R:Wiring ConfigurationSingle or 3-Phase Winding Configuration Neutral Grounding System Used: (Choosewell if applicable6.Anti-Islanding ProtectionCPS Energy Instructions: Please describe in detail the anti-islanding protection scheme, as well as, the worst-case time delay for shutting down the DG system. Indicate how long it takes the DG system to disconnect from the grid. Anti-islanding sensing must meet the NEC, IEEE 1547-2018, and UL 1741.Specify the type of DG system you are applying for below:I am applying for a DG Systems with total capacity (including aggregate) of less than25 kW ac in a single parcel of property with single or multiple metersI am applying for a DG Systems with total capacity (including aggregate) of 25 kW ac orgreater in a single parcel of property with single or multiple metersIs the DG system on the Downtown Distribution Network system?--------------------------------------------------------------------------------------------------------------------- CPS Energy internal use onlyCPS Energy Reviewer Comments:CPS Energy Reviewer Name (Print):Signature: Date:By executing this Application, the DG Owner, or its authorized representative, certifies that the information in the Application is true and accurate and DG Owner certifies that they have read, understand and agree to comply with all CPS Energy terms and conditions as stated or incorporated in the current DG Manual, including the Interconnection Requirements and the Interconnection Terms,applicable CPS Energy Rates and Riders, Rules and Regulations and Service Standards, which shall prevail over any inconsistent provisions in any form or acknowledgement submitted by the DG Owner. Any additional terms or different terms proposed by DG Owner are rejected unless expressly agreed to in writing by CPS Energy.DG Owner or authorized representative printed name, Title/Position:__________________________________________Signature: ____________________________ Date: ______________________________。

电力英语词汇汇总一、电力系统基本词汇1. 电站（Power Station）2. 发电机（Generator）3. 变压器（Transformer）4. 断路器（Circuit Breaker）5. 线路（Transmission Line）6. 电容器（Capacitor）7. 电抗器（Reactor）8. 继电器（Relay）9. 保护装置（Protection Device）10. 控制系统（Control System）二、电力设备与部件1. 母线（Busbar）2. 避雷器（Surge Arrester）3. 电缆（Cable）4. 绝缘子（Insulator）5. 钢筋（Rebar）6. 混凝土（Concrete）7. 齿轮（Gear）8. 轴承（Bearing）9. 油箱（Tank）10. 油冷却器（Oil Cooler）三、电力工程术语1. 电力工程（Electric Power Engineering）2. 设计规范（Design Specification）3. 施工图纸（Construction Drawing）4. 工程预算（Project Budget）5. 施工方案（Construction Scheme）6. 质量验收（Quality Acceptance）7. 安全生产（Safety Production）8. 环境保护（Environmental Protection）9. 节能减排（Energy Saving and Emission Reduction）10. 智能电网（Smart Grid）四、电力行业组织与机构1. 国家能源局（National Energy Administration）2. 电力公司（Electric Power Corporation）3. 电力设计院（Electric Power Design Institute）4. 电力科学研究院（Electric Power Research Institute）5. 电力行业协会（Electric Power Industry Association）6. 电力工会（Electric Power Trade Union）7. 电力市场（Electricity Market）8. 电力监管机构（Electric Power Regulatory Authority）9. 电力消费者协会（Electric Power Consumer Association）10. 国际电力组织（International Electric Power Organization）五、电力技术与发展1. 火力发电（Thermal Power Generation）2. 水力发电（Hydroelectric Power Generation）3. 核能发电（Nuclear Power Generation）4. 风能发电（Wind Power Generation）5. 太阳能发电（Solar Power Generation）6. 新能源（New Energy）7. 分布式发电（Distributed Generation）8. 电动汽车（Electric Vehicle）9. 能源互联网（Energy Internet）10. 电力系统自动化（Electric Power System Automation）六、电力运行与维护1. 电网调度（Power Grid Dispatching）2. 运行监控（Operation Monitoring）3. 设备巡检（Equipment Patrol Inspection）4. 预防性维修（Preventive Maintenance）5. 故障处理（Fault Handling）6. 状态检修（ConditionBased Maintenance）7. 安全操作（Safe Operation）8. 电力可靠性（Electric Power Reliability）9. 负荷预测（Load Forecasting）10. 电力质量（Power Quality）七、电力法律法规与政策1. 电力法（Electricity Law）2. 电力市场监管条例（Electricity Market Regulation）3. 电力设施保护条例（Regulations for the Protection of Electric Power Facilities）4. 电力供应与使用条例（Regulations on Electric Power Supply and Use）5. 电力价格政策（Electricity Pricing Policy）6. 电力体制改革（Electricity System Reform）7. 能源发展战略行动计划（Energy Development Strategy Action Plan）8. 环境保护法律法规（Environmental Protection Laws and Regulations）9. 节能减排政策（Energy Saving and Emission Reduction Policy）10. 电力行业发展规划（Electric Power Industry Development Plan）八、电力市场与交易1. 电力市场交易规则（Electricity Market Trading Rules）2. 电力中长期合同（Longterm Electricity Contract）3. 电力现货市场（Electricity Spot Market）4. 电价形成机制（Electricity Price Formation Mechanism）5. 售电公司（Electricity Sales Company）6. 用户侧响应（Customer Side Response）7. 跨区电力交易（Crossregional Electricity Trade）8. 电力市场分析（Electricity Market Analysis）9. 电力市场竞争（Electricity Market Competition）10. 电力市场风险管理与控制（Electricity Market Risk Management and Control）九、电力行业发展趋势1. 电力行业数字化转型（Digital Transformation of Electric Power Industry）2. 电力系统灵活性（Flexibility of Electric Power System）3. 电力储能技术（Electricity Storage Technology）4. 电力需求侧管理（Electricity Demand Side Management）5. 电力行业智能化（Intelligence of Electric Power Industry）6. 电力行业绿色低碳发展（Green and Lowcarbon Development of Electric Power Industry）7. 电力行业国际合作（International Cooperation inElectric Power Industry）8. 电力行业人才培养（Talent Training in Electric Power Industry）9. 电力行业科技创新（Technological Innovation in Electric Power Industry）10. 电力行业可持续发展（Sustainable Development of Electric Power Industry）十、电力行业热点问题1. 电力供需平衡（Electricity Supply and Demand Balance）2. 电力系统安全稳定（Safety and Stability of Electric Power System）3. 电力扶贫（Electricity Poverty Alleviation）4. 电动汽车充电基础设施建设（Electric Vehicle Charging Infrastructure Construction）5. 电力行业去产能（Capacity Reduction in Electric Power Industry）6. 电力行业环境保护（Environmental Protection in Electric Power Industry）7. 电力行业信用体系建设（Credit System Construction in Electric Power Industry）8. 电力行业反垄断（Antitrust in Electric Power Industry）9. 电力行业对外开放（Openingup of Electric Power Industry）10. 电力行业社会责任（Social Responsibility of Electric Power Industry）十一、电力技术创新与应用1. 智能电网技术（Smart Grid Technology）2. 分布式能源系统（Distributed Energy Systems）3. 微电网技术（Microgrid Technology）4. 能量管理系统（Energy Management System）5. 高压直流输电（High Voltage Direct Current Transmission）6. 超导技术（Superconductivity Technology）7. 电力电子技术（Power Electronics Technology）8. 量子计算在电力领域的应用（Application of Quantum Computing in Electric Power Field）9. 大数据与电力系统分析（Big Data and Electric Power System Analysis）10. 云计算在电力行业的应用（Application of Cloud Computing in Electric Power Industry）十二、电力工程项目管理1. 项目可行性研究（Project Feasibility Study）2. 项目立项（Project Approval）3. 项目招投标（Project Bidding）4. 项目合同管理（Project Contract Management）5. 项目进度控制（Project Schedule Control）6. 项目成本管理（Project Cost Management）7. 项目质量管理（Project Quality Management）8. 项目风险管理（Project Risk Management）9. 项目验收与移交（Project Acceptance and Handover）10. 项目后评价（Project Postevaluation）十三、电力行业职业素养与技能1. 电力工程师职业道德（Professional Ethics for Electrical Engineers）2. 电力行业职业技能培训（Vocational Skills Training in Electric Power Industry）3. 电力行业职称评定（Professional Title Evaluation in Electric Power Industry）4. 电力行业从业资格证书（Qualification Certificates in Electric Power Industry）5. 电力行业创新能力培养（Innovation Ability Training in Electric Power Industry）6. 电力行业团队协作（Team Collaboration in Electric Power Industry）7. 电力行业沟通与协调能力（Communication and Coordination Skills in Electric Power Industry）8. 电力行业应急处理能力（Emergency Handling Ability in Electric Power Industry）9. 电力行业法律法规知识（Legal Knowledge in Electric Power Industry）10. 电力行业国际视野（International Perspective in Electric Power Industry）十四、电力行业国际合作与交流1. 国际电力组织（International Electric Power Organizations）2. 国际电力展览会（International Electric Power Exhibitions）3. 国际电力技术交流（International Electric Power Technology Exchange）4. 国际电力项目合作（International Electric Power Project Cooperation）5. 国际电力市场分析（International Electric Power Market Analysis）6. 国际电力标准制定（International Electric Power Standards Development）7. 国际电力人才培养与合作（International Electric Power Talent Training and Cooperation）8. 国际电力政策研究（International Electric Power Policy Research）9. 国际电力环境保护合作（International Electric Power Environmental Protection Cooperation）10. 国际电力行业发展趋势探讨（Discussion on International Electric Power Industry Development Trends）。

A BENCHMARK LOW VOLTAGE MICROGRID NETWORKStavros Papathanassiou* Nikos Hatziargyriou Kai StrunzNational Technical University of Athens University of WashingtonGREECE USAKeywords: Distributed Generation, Distribution Networks, LV Networks, Microgrids1. INTRODUCTIONThe increasing penetration of distributed generation resources to the low voltage (LV)grids, such as photovoltaics, CHP micro-turbines, small wind turbines in certain areas andpossibly fuel cells in the near future, alters the traditional operating principle of the grids. A particularly promising aspect, related to the proliferation of small-scale decentralized generation, is the possibility for parts of the network comprising sufficient generating resources to operate in isolation from the main grid, in a deliberate and controlled way. Theseare called Microgrids and the study and development of technology to permit their efficient operation has recently started with a great momentum ([1,2]).Microgrids are foreseen within public distribution grids and therefore suitable study case networks are required to perform simulation and analysis tasks. Moreover, standardizingstudy case grids to provide “benchmark” networks suitable for Microgrid design wouldfurther enhance their merit and utility.The objective of this paper is to present and discuss a benchmark LV network developedwithin the EU project “Microgrids”, Contract ENK5-CT-2002-00610 and later adopted as a benchmark LV system by CIGRE TF C6.04.02: “Computational Tools and Techniques for Analysis, Design and Validation of Distributed Generation Systems”. The network consists ofan LV feeder, while a more extended multi-feeder version is also included in the Appendix ofthe paper. The emphasis is placed on the network itself, rather than on the microsources connected and the control concepts applied. The benchmark network maintains the important technical characteristic of real life utility grids, whereas, at the same time, it dispenses withthe complexity of actual networks, to permit efficient modeling and simulation of the microgrid operation.2. THE BENCHMARK LOW VOLTAGE FEEDER2.1 General Characteristics of the LV NetworkBefore presenting the benchmark network, some important technical characteristics of public LV distribution grids are summarized (pertaining more to European networks): Structure. The majority of LV public distribution networks have a radial layout, with a number of LV feeders starting from the LV busbars of the infeeding MV/LV substation. Each feeder may include one or more spurs (branches). Consumers are connected anywhere along the feeder or its spurs.Symmetry. The connection of single-phase consumers makes LV networks inherently unbalanced. In addition, single-phase lines may exist, particularly as feeder branches. Substation. The MV/LV substation feeding the LV network typically comprises a single transformer with a rating of a few hundred kVA up to 1 MVA. The transformer is equipped with off-load taps at the HV winding, providing a typical regulation range of ±5%. Its connection group is usually Dyn11, corresponding to a delta-connected primary and a wye-connected secondary winding.Protection. The only protection encountered in public LV networks typically consists of simple phase overcurrent devices, most commonly fuses. The MV/LV transformer is protected by fuse links at the MV side. A general protection element may not exist at the output of the transformer LV winding, whereas each LV feeder is protected by its own fuses. No other protection means are utilized along the feeder or its branches.Line types. LV network lines are either underground cable lines, encountered mainly in urban areas with a high load density, or most commonly overhead lines, traditionally constructed by Al (or Cu) bare conductors. Ease of installation and environmental reasons have led to the extensive use of twisted insulated conductors for overhead LV lines during the last decades. Earthing. Using the classification of IEC 60364, public LV networks are either of the TN or the TT type. The principle of each earthing scheme is illustrated in Fig. 1. More information on the subject is provided in [3,4].PhPENFigure 1. Principle of the TN and TT earthing schemes.2.2 Description of the Benchmark LV FeederBased on the basic requirements discussed in the previous section, the study case LV feeder is illustrated in Fig. 2. The feeder is an overhead line with twisted XLPE cable, serving a suburban residential area with a limited number of consumers connected along its length, as well as at the end of the branch at its middle. Line types are marked on the diagram and the respective parameters are given in the Appendix. Section lengths can be determined from the number of poles, given the fixed pole-to-pole distance of 35 m. The network neutral is multi-grounded, at the substation, at every second pole and at each consumer connection point. At the end of the lateral branch, a connection of the neutral may exist to an adjacent LV line (fed by another substation).consumer3Φ, I s =40 A S max =15 kVA S 0=5.7 kVA4 x 3Φ, I s S max =55 kVA S 0=25 kVAAppartment building1 x 3Φ, I s =40 A 6 x 1Φ, I s =40 A S max =47 kVA S 0=25 kVA40 ΩLV network line Connection cable To consumer installation Overhead line pole Point of connection (supply)Neutral earthing Fuses3+N+PE5 conductor cable (3 phases,neutral, protective earth)LEGENDFigure 2. The benchmark LV feeder, in its standard (“non-microgrid”) form.The arrangements at the service connection of each customer are presented in more detail in Fig. 3. Each service connection includes the electricity meter and an overcurrent protection element (fuse links or a miniature circuit breaker for small consumers). For the service cable, a standard 30 m length is adopted in Fig. 2. The earthing scheme of the network may be eitherof the TN or the TT type, depending on the connection or not of the PE conductor of the consumer installation to the network neutral. The 40 Ω earthing resistances noted on the diagram correspond to a standardized conductive rod, 2.5 m long by 0.02 m in diameter, buried in homogeneous conductive earth of 100 Ω.m resistivity. The apartment building on the lateral is supposed to have a more effective earthing arrangement (either multiple rods or some sort of foundation earth).MCB for small sizesConsumergroundFig. 3. Typical service connection arrangement.2.3 Consumer Demand CharacteristicsEach consumer of the feeder is characterized by a maximum permissible current, I s, which corresponds to the rated current of the overcurrent protection element in the connection box (Fig. 3). The maximum demand S max of each consumer group, also given in Fig. 2, is depends on the number of individual consumers within each group, and is found using standardized coincidence factors for residential consumers, which become smaller as the number of consumers increases (e.g. [5]). For this reason, the contribution S0 of each group to the maximum demand of the feeder will be further reduced, as given in Fig. 2. The total maximum demand of the feeder is 116.4 kVA. The power factor of all consumers may be assumed equal to 0.85 lagging. Aggregate daily load curves are provided in the Appendix.3. THE BENCHMARK LOW VOLTAGE MICROGRID NETWORKBased on the LV feeder of Fig. 2, the benchmark LV microgrid network shown in Fig. 4 is derived. It includes representative sources from all currently important (or emerging, but promising) technologies, such as photovoltaics, microturbines (CHP generation), wind turbines and fuel cells.Specific technical details, models for individual sources and control concepts are beyond the scope of this paper and will be specified in application studies. In Fig. 4, only relevant installation locations and sizes are indicated. The total installed capacity of the microsources is about 2/3 of the maximum load demand of the feeder (~100 kW), to provide the possibility of simulating load management scenaria.To support the islanded operation of the microgrid, a fast-responding central storage unit is also considered, which may be either a battery inverter, or any other device with sufficiently fast response to undertake the frequency regulation task upon disconnection from the grid (e.g. a flywheel). Notably, this constitutes a centralized control approach. Alternatively, the individual microsources might be equipped with local storage (e.g. batteries or ultra-capacitors) and suitable controls to ensure a decentralized active power/frequency concerted regulation ([6]).(or batteries)3Φ, 30 kWPhotovoltaics1Φ, 4x2.5 kWWind Turbine3Φ, 10 kWFuel Cell3Φ, 10 kWFigure 4. Benchmark LV microgrid network.Compared to the standard LV feeder of Fig. 2, in Fig. 4 the fuses at the feeder departure have been replaced by a circuit breaker, in order to permit the controlled connection and isolation of microgrid from the main grid. A second sectionalizing breaker may also be inserted at the middle of the feeder, if selective isolation of faulted parts of the microgrid is to be studied. However, in such a case, suitable frequency regulating means should be foreseen in each isolated section.The earthing arrangements of the network remain unchanged for microgrid operation. Preliminary investigations have shown that this is acceptable ([7]), although further study may be required on this subject. Regarding the protection philosophy, devices and settings, it is certain that modifications will be required to the traditional LV network practice, which have not been incorporated in the study case network of Fig. 4.4. CONCLUSIONSIn this paper a benchmark LV microgrid network is presented, which is suitable for steady state and transient simulations. The study case network is based on a standard LV feeder, where microsources and storage devices of various types are connected. A more extended network is also provided in the Appendix, to facilitate the simulation of multi-feeder microgrids or multiple microgrids within the same LV grid.5. ACKNOWLEDGEMENTThe work presented in this paper has been performed within the project “MICROGRIDS: Large Scale Integration of Micro-Generation to Low Voltage Grids” (Contract ENK5-CT-2002-00610), funded by the EU. The authors wish to thank Mr. N. Soultanis for calculating the zero sequence parameters of the lines.6. REFERENCES[1] EU Project “MICROGRIDS: Large Scale Integration of Micro-Generation to LowVoltage Grids (ENK5-CT-2002-00610)”. Website: http://microgrids.power.ece.ntua.gr/. [2] R. Lasseter, A. Akhil, C. Marnay, J. Stephens, J. Dagle, R. Guttromson, A.S. Meliopoulos,R. Yinger and J. Eto, “White Paper on Integration of Distributed Energy Resources–The CERTS MicroGrid Concept”. LBNL-50829, US Department of Energy, Office of Power Technologies. Contract DE-AC03-76SF00098.[3] B. Lacroix, R. Calvas, “Earthing systems in LV”. Cahier Technique No. 172, SchneiderElectric, 2000.[4] B. Lacroix, R. Calvas, “Earthing systems worldwide and evolutions”. Cahier TechniqueNo. 173, Schneider Electric, 1995.[5] “Standardization of Electricity Meters”, Distribution Directive No.45, Public PowerCorporation (PPC) of Greece, 1982.[6] D. Georgakis, S. Papathanassiou, N. Hatziargyriou, A. Engler, C. Hardt, “Operation of aprototype Microgrid system based on micro-sources equipped with fast-acting power electronics interfaces”. Proceedings of PESC’04, June 2004, Aachen, Germany.[7] “Safety Guidelines: Report with proposed earthing and safety procedures to ensure safe operation of the Microgrid”, Microgrids Deliverable DE1, Dec. 2004.7. APPENDIXA more extended study case LV network is included in Fig. 5, which comprises two additional LV lines, compared to the benchmark network of Fig. 2. The first is a dedicated underground cable line, serving a workshop, whereas the other one is an overhead line serving a small commercial district. The diagram provides for each consumer the same information as in Fig. 2. On the commercial load feeder, where a large number of single-phase consumers are connected, the respective phases are also noted.The study case network of Fig. 5 permits the simulation of microgrids with multiple LV feeders and diverse load types, or even different microgrid entities within the same LV network (e.g. by considering that the commercial line forms a second microgrid, with CHP microturbines as microsources). Depending on the part of the network, which forms the microgrid (or microgrids), sectionalizing switches need to be inserted at selected locations and suitable microsource scenaria must be adopted.73Φ, I S max S 04 x 3Φ, I s S max =55 kVA S 0=25 kVA1 x 3Φ, I s 6 x 1Φ, I s S max S 0=25 kVAΩ4x50 mm2 Al conductors4x35 mm2 Al conductorsResidentialloadFigure 5. Benchmark LV network for the study of multi-feeder or multiple LV microgrids.Aggregate daily load curves for the three load types of the benchmark networks are shown in Fig. 6. Impedance data for the various line types are provided in Table 1. Neutral resistances are given where the neutral has a different cross section than the phases. Calculated zero sequence impedances are quoted for selected line types, appearing in the benchmark network of Fig. 4 (derived for combined neutral and earth return path of the current).Table 1. Impedance data for the benchmark network linesLine typeR ph (Ω/km) X ph (Ω/km) R neutral (Ω/km) R 0(Ω/km) X 0(Ω/km)1 OL - Twisted cable 4x120 mm2 Al 0.284 (1)0.083 1.136 0.4172 OL - Twisted cable 3x70 mm 2 Al + 54.6 mm 2 AAAC 0.497 (1)0.086 0.630 2.387 0.4473 OL - Al conductors 4x50 mm 2 equiv. Cu 0.397 (1)0.2794 OL - Al conductors 4x35 mm 2 equiv. Cu 0.574 (1)0.2945 OL - Al conductors 4x16 mm 2 equiv. Cu 1.218 (1)0.3186 UL - 3x150 mm 2 Al + 50 mm 2 Cu 0.264 (2)0.071 0.387 (2)7 SC - 4x6 mm 2 Cu 3.690 (3)0.094 13.64 0.4728 SC - 4x16 mm 2 Cu 1.380 (3)0.082 5.52 0.4189 SC - 4x25 mm 2 Cu 0.871 (3)0.081 3.48 0.40910 SC - 3x50 mm 2 Al + 35 mm 2 Cu 0.822 (2)0.077 0.524 (2)2.04 0.42111 SC - 3x95 mm 2 Al + 35 mm 2 Cu 0.410 (2)0.071 0.524 (2)OL: Overhead line, UL: Underground line, SC: Service connection (1): Ohmic resistance at 50 o C conductor temperature(2): Ohmic resistance at temperature 90 o C for phase conductors and 20 o C for the neutral (3): Ohmic resistance at temperature 70 o C for all conductorsSummaryMicrogrids are foreseen to be developed within public distribution grids and therefore suitable study case networks are required to perform simulation and analysis tasks. Standardizing study case grids to provide “benchmark” networks suitable for microgrid development, further enhances their merit and utility. In the paper a benchmark LV network is presented and discussed, consisting of a LV feeder supplying a suburban residential area. A more extended version of the benchmark network is also included, suitable for the study of multi-feeder or multiple microgrids. The emphasis is placed on the network characteristics, while microsources, representative of all currently important technologies, are connected to selected nodes. The benchmark network maintains the important technical characteristic of real life utility grids, while dispensing with the complexity of actual networks, to permit efficient modeling and simulation of microgrid operation.。

automatic controlAutomatic control is relatively artificial control terms ，which refers to correlate with no people directly involved in conditions, the additional equipments or devices to make the machine, equipment or the production process of a certain job of state or parameters automatically set to run the rule.Automatic control technology research will benefit mankind from complicated, risky, tedious work environment free of control and greatly improve the efficiency. Automatic control is a branch of engineering science. It involves using a feedback of dynamic system of the principle of automatic influence, in order to make the output value close with that we set value. From the theory of methods, the mathematical theory is a foundation of Automatic control. As we known today, as automatic control is in the middle of the twentieth century from the control of a branch. The conclusion is based by Norbert wiener, Rudolf kalman proposes.1.The first generation process Control System(PCS)The first generation process Control System is based on 5-13 psi Pneumaticrebefo signal standard ( Pneumatic Control System) PCS before 150 years ,which includes simple on-site operation mode, control theory preliminary form. There does not has been the concept of the control room.2.The second generation process Control System(ACS)The second generation process Control System (ACS or Analog Control System) Analog to produce stats are based on 0-10 mA or 4-20 mA's current Analog signals, the obvious progress of the Control System is that to rule the whole firmly automatic Control field in the whole 25 years. It represents the arrival of the era of electrical automatic control. Control theory has the significant development, the establishment of the three big cybernetics laid the foundation of modern control; The establishment of control function, control room separate model has been used today.3.The third generation of process Control System(CCS)The third generation of process Control System, Computer Control System (CCS) began in t he 70’s ,the application of digital Computer has a great technical advantage, people in measurement, simulation and logic Control field, whichpioneered the use of the third generation process Control System, Computer Control System (CCS). This is called the third generation process control system is automatic control a revolution in the field, it give full play to the computer specialty, so it is widely acknowledged that computer can do all things, naturally produced is called "the centralized control" of the central control computer system, it should be pointed out that the signal transmission system is still the most used with 4-20 mA analog signals, but soon after that, as people focus and reliability of the control aspects of the problem, the out of control risk also focused on, a little wrong will make the whole system to paralysis. So it was quickly developed into the distributed control system (DCS).4.The fourth generation process Control System(DCS)With the rapid development of semiconductor manufacturing technology, the microprocessor to the widespread use of computer technology greatly increased, the reliability of the currently used is the fourth generation process Control System (DCS, or Distributed digital Control System), it is the main features of the whole Control System that there is no longer only a computer, it is a Control System by a computer and some intelligent instruments and intelligent components comprise. So the way of distributed control became the most important characteristic. Another important development exception is the signal transmission among of them are not based on 4-20 mA analog signals, and gradually digital signal to replace analog signals.5.The fifth generation process Control System (FCS)The development of FCS from the DCS, like DCS from CCS over the development as, there is a qualitative leap, that is "Distributed control" developed to " focused control". The way of data transmission is "bus" way. The so-called field-bus is intelligent measurement and control equipment conect all the digital, two-way transmission, with many node of the structure of the branch communications link. Say simply traditional control is a loop, and FCS technology is modules such as controller, actuators, detector etc on a bus to hang up realize communication, of course, transmission is the digital signal. The main bus has Profibus, LonWorks, etc. But the real with DCS FCS difference is to have a more FCS wide development space. Because the traditional DCS technical level while continuously improved, but themost low-end only communication network to the control station level, the control station and the field measurement instrument, the contact between the actuators are still used one-to-one transmission of 4-20 mA analog signals, high cost, low efficiency, maintenance difficulties, can't play the field instruments, to realize the potential of the intelligent field device the work state of comprehensive monitoring and deep management..In the modern science and technology in many fields, automatic control technology is playing a more and more important role. Automatic control theory is the study of the automatic control of common laws technology science. Its initial development stage, is based on the theory of the feedback of automatic adjustment principle, mainly for industrial control, during world war two, in order to design and manufacture the plane and Marine autopilot, gun positioning system, radar tracking system based on feedback and other military equipment, the principle of further promote and perfect the development of the theory of automatic control. After the war, in order to form the full automatic control theory system, which is the transfer function is the foundation of classical control theory, it mainly studies single input and single output, the linear system analysis and set constant design problem.Automatic control of the development, from the start of the happen to form a control theory, the whole that process. Speak Automatic control is refers to such feedback control system, this is a controller object with a control of the control object, the output signal get it back, after come back for measuring with the signal are compared. According to the error tell controller, which is within the machine work. Let the controller to complete the control effect, make the deviation eliminate or make the controlled objects output tracking what I need to be requirements of the signal. The controlled objects output in general is a physical quantities, for example say me to control a machine speed, is need to come out, to measure the speed control.Saying to hear I have to mention is the "engineering cybernetics qian xuesen". Qian xuesen, written in 1954, when his book in the United States, we wrote the book here also can't get in English, but the former Soviet union very seriously, the former Soviet union immediately translate it into Russian. We see of the former Soviet union was in 1956 put his Russian, translation come out, we see at that time is the Russianversion of, this is in about twenty s the formation process of the main process, the experience is concluded.The robust leaves (Lurie) in the former Soviet union in 1944 about him out to everybody now make nonlinear may know, out to a robust leaves in question, this problem has been not solve, he later to write a book, is to keep the problem. The problem, start to when? I said something about this here two style, British and American of just everybody has to come out, make the person is engineering in make control, the former Soviet union is the application with mechanics in make home mathematician control, so two played the role is not the same. His 1951 book at that time is very hard to understand, hard to read. This work, he brought out the robust, Lurie), (until 1960, someone out to solve a solution, we may know, is that the absolute Popov) Popov (stability. Then out of the stability and is robust to solve this problem, Lurie (in). That is the book was 20 s, twenty century in the late '40 s, 50 s, some of the work has been influence of the twentieth century, but also affects the 60 s to present some nonlinear theory, is his work for the foundation. The twentieth century is in the 40 s, front of the development of the technology is a process, slowly forms a theory. I'm used to in such a schedule to said 50 s, most of the time, call classical control theory; 60 s call the state space method, is actually state space method, but you know, at that time, the name of the called it the modern control theory; Then in the 70 s is the modern the frequency domain method, such a process.The next now is to explain the state space method, finished that modern control theory. The state space method who first brought out? The third book is just of the former Soviet union, these scholars. They make applied mathematics and mechanics, they never get the is used is the state space method. In 1960, it introduced to kalman English world, so the world it is spending in English, that means the country want English country, because it was all don't know, kalman is a Slavic name. In 1960, he, he put the state space method introduced to the United States. But add people to this hype, modern control theory to hype seem very much as gods, was also some people expected is relatively large. This is the development of the ten years later, he found too, like the expected only so! Some problem you didn't also solved. So the time, and some people back to the frequency domain method, is the earliest 50 s is thefrequency domain method, 60 s, 70 s state space and back to the frequency domain method.Of course, this is the spiral, this time the frequency domain method and then add a name, so that the modern the frequency domain method. Think frequency domain to consider the design problems or more appropriate, consider some of the design requirements, I just have this frequency domain method. Just in the modern the frequency domain method development on this momentum, 1981, and wrote you this no said robust, we now everyone make control theory know to robust design. Say you this modern the frequency domain method not robustness, when people do not believe, after the 80 s, the arguments that dispute slowly forms. By 1991, is now of course is that you may be someone the term does not necessarily unification, someone called it the modern control theory, Postmodern after keep control. We now have to go back to see, why do you say that no robustness? One will say, we from the many variable system, it is actually much more variable system into the system. Many variables don't appropriate, there is a lot of input, output a. Many avariable a problem, called the coupling, is between input and output coupling each other. Control, intuitive request was for decoupling control, decoupling control later! Is this the 1 to 1 can form output feedback system, the 2! with the 2 of output can form feedback systems, and the design will be easier.自动控制自动控制（automatic control）是相对人工控制概念而言的，指的是在没有人直接参与的情况下，利用外加的设备或装置，使机器、设备或生产过程的某个工作状态或参数自动地按照预定的规律运行。

中国可再生能源英语作文Renewable Energy in ChinaChina, the world's most populous country and the second-largest economy, has been at the forefront of the global transition towards a more sustainable future. As the world grapples with the pressing issue of climate change, China has recognized the urgent need to reduce its carbon footprint and has made significant strides in the development and implementation of renewable energy sources.One of the primary drivers behind China's push for renewable energy is the country's growing energy demand. With a rapidly expanding economy and a burgeoning population, China's energy consumption has skyrocketed in recent decades. Conventional fossil fuels, such as coal and oil, have long been the backbone of China's energy mix, but the environmental toll of these energy sources has become increasingly apparent.In response, the Chinese government has implemented a comprehensive strategy to diversify the country's energy portfolio and promote the use of renewable energy. This strategy has been underpinned by a series of ambitious targets and policy initiativesdesigned to accelerate the transition towards a more sustainable energy system.At the heart of this strategy is China's commitment to the development of renewable energy sources, including solar, wind, hydropower, and biomass. The country has made remarkable progress in this regard, with China now leading the world in the installation of renewable energy capacity.One of the most impressive achievements in China's renewable energy journey is the rapid growth of its solar power industry. China has emerged as the global leader in solar energy, with an installed capacity that far exceeds that of any other country. The government has invested heavily in the construction of large-scale solar power plants, as well as in the promotion of distributed solar generation, which involves the installation of solar panels on rooftops and other small-scale applications.Similarly, China has also made significant strides in the development of its wind power sector. The country is home to some of the world's largest wind farms and has been rapidly expanding its wind power capacity in recent years. This growth has been driven by a combination of government support, technological advancements, and the availability of vast wind resources in many parts of the country.In addition to solar and wind power, China has also been actively promoting the use of hydropower and biomass energy. Hydropower, in particular, has long been a significant contributor to China's energy mix, with the country boasting some of the world's largest hydroelectric dams. Meanwhile, the use of biomass energy, derived from organic materials such as agricultural waste and forestry residues, has been on the rise, as the country seeks to diversify its renewable energy portfolio.The benefits of China's renewable energy push are multifaceted. Firstly, the increased use of renewable energy sources has led to a significant reduction in the country's greenhouse gas emissions, contributing to the global effort to mitigate the effects of climate change. Additionally, the development of renewable energy industries has created numerous job opportunities and stimulated economic growth, particularly in rural and remote areas where renewable energy projects are often located.Furthermore, the investment in renewable energy has also brought about technological advancements and improvements in energy efficiency. China's renewable energy sector has become a hub of innovation, with the country leading the way in the development of cutting-edge technologies and the implementation of smart grid systems to better integrate renewable energy into the electric powergrid.Despite these impressive achievements, China's renewable energy journey is not without its challenges. The country's vast size and diverse geographical landscape pose unique challenges in terms of grid integration and energy transmission. Additionally, the transition away from fossil fuels has created economic and social disruptions, particularly in regions where coal mining and other fossil fuel-based industries have been the backbone of the local economy.To address these challenges, the Chinese government has implemented a range of policies and initiatives to support the continued growth of the renewable energy sector. This includes the provision of financial incentives, such as feed-in tariffs and tax credits, as well as the development of a robust regulatory framework to promote the adoption of renewable energy technologies.Moreover, the government has also recognized the importance of addressing the social and economic impacts of the energy transition. It has invested in retraining programs and job creation initiatives to support workers and communities affected by the decline of fossil fuel industries, ensuring a just and equitable transition to a low-carbon economy.In conclusion, China's renewable energy journey is a testament to thecountry's commitment to sustainability and its willingness to take bold action in the face of pressing environmental challenges. The rapid growth of the renewable energy sector in China has not only had a significant impact on the country's energy landscape but has also set a global example for other nations to follow. As the world continues to grapple with the urgent need to address climate change, China's renewable energy story stands as a powerful reminder of what can be achieved through strategic vision, policy support, and technological innovation.。

基于PSCAD的分布式电源VF控制基于PSCAD的分布式电源VF控制摘要：本文首先介绍了分布式发电的背景，分布式发电的发展情况。

本文其次介绍了三相逆变器的SPWM逆变器结构和控制，同时也分析了影响SPWM逆变器性能的因素。

然后，本文由三相电压型逆变器主电路推导出控制的数学模型，进而推出三相电压型逆变器的电压控制方程和框图，电流控制方程和框图，以此得出电压电流双环控制框图。

最后为验证所设计的并网逆变器各种参数的正确性及功率控制器的有效性，本文通过计算机常用仿真软件EMTDC/PSCAD进行仿真。

仿真结果验证了采用电压外环电流内环双环控制的有效性。

关键词：分布式发电；SPWM控制理论；三相桥式逆变器；电压电流双环控制；解藕控制；EMTDC/PSCAD 仿真Abstract：This paper first introduced the background and the development situation of distributed power generation. Secondly, this article discusses the structure and control of SPWM inverter of three-phase inverter, analyzes the factors affecting the performance of the SPWM inverter. Also this article deduced the mathematical model from main circuit of the three-phase voltage source inverter. In this paper, we can launch voltage ,current control equation and chart of inverter by mathematical equations of d-q coordinate axes, then we concludes voltage and current dual loop control diagram.Finally, we used to using computer simulation software EMTDC / PSCAD to simulation，in order to verify that the inverter parameters of design is correct and the power controller is effective. The effectiveness of voltage outer loop current inner loop control is verified by the simulation results.Keywords: Distributed generation； SPWM control theory； Three-phase bridge inverter；Voltage and current dual-loop control； Decoupling control； EMTDC / PSCAD simulation1 引言21 世纪，世界面临着经济和社会可持续发展的双重挑战，必须在节约资源和环境保护要求的双重制约下发展经济。