ZEFAL The Zero Fault Level Generator for Active Urban Networks

目前由伦敦市长发布的伦敦计划要求，10%的能源需求应通过现场可再生能源发电来满足。2007年2月公布的对伦敦计划的进一步修改草案更进一步，明确要求新开发项目在可行的情况下由联合制冷、供热和发电(CCHP)系统提供能源，并通过生产现场可再生能源发电进一步减少20%的二氧化碳排放。预计英国、欧洲和国际上的其他主要城市将效仿这种方法的变化，所需的百分比将随着时间的推移而上升。高负荷密度地区(如主要城市)内本地发电的快速扩张正在迅速侵蚀现有配电网上剩余的可用故障水平净空。2003年的一项调查表明，大约200个变电站的故障水平剩余净空不足5%，72%的英国变电站(900个)的净空低于25%。已经在伦敦的码头、伦敦金融城和伦敦西区，净空接近或接近于零。每年1.5至3.5兆伏安的6个方案由于故障水平的限制而无法进行。使用传统工程解决方案克服故障级别限制所需的总计5-1000万pa的额外连接费用，使这些方案对开发商来说不经济。这一数字预计在2007/8年度将翻一番。拟议的发展将从源头上解决这一问题，允许大量旋转电机发电机连接到城市和城市网络，而不会造成故障水平。这将允许快速和低成本地连接许多其他导致故障的设备，如常规电机和发电机以及光伏电源和感应风力发电机。这一问题的严重性意味着，国际上已经在研究和开发各种故障级别管理解决方案，包括超导和电力系统电子方法。这些发展旨在为现有网络提供更大的故障级别净空。这被视为对潜在地消除新型旋转发电机的故障水平贡献的必要和补充，特别适用于冷热电联产和从废物中产生生物质。缺乏故障水平净空是英国城市减少二氧化碳排放所需的国家和地区规划政策所要求的分布式发电快速和经济连接的主要制约因素。在这一基础研究阶段，我们的目标是确定开发用于有源城市电网的零故障电平发生器的可行性，并生产出一台25-50kW范围的示范发电机，具有完全的故障穿越能力，并在正常运行和故障后恢复中为电压、无功和频率支持做出积极贡献。

The current London Plan issued by the Mayor of London, requires that 10 per cent of energy demand should be met through on-site renewable generation. Draft Further Alterations to the London Plan published in February 2007 go one step further by specifically requiring new developments to have energy supplied by Combined Cooling Heating and Power (CCHP) systems wherever feasible and to reduce their CO2 emissions by a further 20 per cent through the production of onsite renewable energy generation. It is expected that other major cities both in the UK, Europe and internationally will follow variations of this approach and that the required percentages will escalate over time The rapid expansion of local generation within high load density areas - such as major cities - is rapidly eroding the remaining available fault level headroom on existing distribution networks. A survey in 2003 indicated that some 200 substations had less than 5% fault level headroom remaining and that 72% of UK substations (900) had less than 25% headroom. Already in London's Docklands, City and West End where headroom is near or at zero, approx. 6 schemes each of 1.5 to 3.5 MVA a year are not proceeding due to fault level constraints. Additional connection charges totalling 5-10m pa, necessary to overcome fault level constraints using conventional engineering solutions, render these schemes uneconomic to the developers. The number is expected to double during 2007/8. The proposed development will tackle this issue at source by permitting the connection of large numbers of rotating machine generators to city and urban networks without contributing to fault levels. This will allow the rapid and low cost connection of many other fault level contributing devices such as conventional motors and generators as well as PV sources and induction wind machines. The criticality of this problem means that a variety of fault level management solutions are already being internationally researched and developed including superconducting and power system electronic approaches. These developments are aimed at providing greater fault level headroom on existing networks. This is seen as being both essential and complimentary to the potential elimination of fault level contributions from a new breed of rotating generators particularly suitable for CCHP and biomass generation from waste. Lack of fault level headroom is a major constraint to the rapid and economic connection of distributed generation required by national and regional planning policies in UK cities to reduce the UK's CO2 emissions. In this basic research stage we aim to establish the feasibility of developing a Zero Fault Level Generator for Active Urban Networks, and to produce a demonstration generator in the 25-50kW range with full fault-ride through capability and provision to make active contributions to voltage, reactive power and frequency support in nromal operation and in post-fault recovery.