Enhanced Renewable Integration through Flexible Transmission Options (ERIFT)

中国安装风力发电场的速度比其他任何国家都快，而英国正在引领海上风力发电场的部署。两国将面临通过（电力）长电缆或架空直流线路将偏远地区的可再生能源连接起来的挑战，以及控制高比例异步发电系统的挑战。该建议确定了共同技术挑战的领域，并制定了一项联合计划，以分析问题并评估可能的解决方案。充分开发潜在的输送能力至关重要；在中国，从西部/中部的水力资源到东部/沿海城市，在英国，从苏格兰和北海的风力资源到南部的负荷中心。一组交流和直流路由的可实现传输容量取决于在不同负载条件下如何安排系统的控制（这会影响稳定性约束）以及配置的风险概况（这会影响冗余和安全原因的卸载）。我们将研究交流、直流和FACTS要素的协调控制，以优化传输能力，并将开发工具来支持运营商的决策，包括风险分析。异步发电比例高的国家输电系统惯性很小，因此需要综合明确的频率响应以将系统频率保持在限制范围内。将研究两个具体方面：在没有明确频率数据通信的情况下，在直流链路上提供频率响应服务的能力（来自远程端风力涡轮机的动能），以及电力转换器（涡轮机和HVDC）所需的净空空间，以适应这种服务。识别和隔离故障设备的保护方案也受到异步发电的影响，因为它们的电源转换器接口提供的短路电流要低得多，难以区分。我们将详细分析这一问题，并提出重新设计保护计划的建议。还将研究广泛使用高压直流输电连接远程可再生资源所带来的一系列技术挑战。首先是多终端HVDC的运行和保护，它将允许直流线路的网格化，从而形成更安全的网络，从而解决潮流和故障管理问题。其次是重新评估风电场收集网络，以消除潜在的浪费能源转换阶段。第三是在高压直流变流器设计上的创新，使中间点的一小部分电力的供应（或馈电）具有成本效益。主要工作计划将由中英两国的博士后研究员进行，每位博士后研究员将在对方国家进行为期3个月的实习，以加深研究团队之间的互动。在中国，博士项目也将围绕重点研究主题进行安排。在英国，这项工作将与大学现有的博士团队合作。一个在中国和英国轮流开会的指导委员会将管理该项目。主要产出将是为评估已查明的问题（对电网系统操作员有用）而制订的分析方法；工程解决方案的建议（对系统操作员和设备供应商有用），并通过规模实验室测试系统和实时模拟验证这些建议。

China is installing wind farms faster than any other nation and the UK is leading deployment of offshore wind farms. Both nations will face challenges in connecting renewable sources in remote areas over (electrically) long cable or overhead DC routes and also challenges in controlling a system with a high proportion of asynchronous generation. This proposal identifies areas of common technical challenge and lays out a joint programme to analyse the issues and assess possible solutions. Fully exploiting the potential transfer capacity is vital; in China this is from western/central hydro resources to eastern/costal cities and in the UK from Scottish and North Sea wind resource to southern load centres. The realisable transfer capacity from a set of AC and DC routes depends on exactly how the control of the system is arranged under differ loading conditions (which affects stability constraints) and on the risk profile of the configuration (which affects the de-loading for redundancy and security reasons). We will investigate coordinated control of AC, DC and FACTS elements to optimise transfer capacity and will develop tools to support operator decision-making including risk analysis. A national transmission system run with a high proportion of asynchronous generation has little inertia and so explicit frequency response needs to be synthesised to maintain the system frequency within limits. Two specific aspects will be investigated: the ability to provide frequency response services across a DC link (from kinetic energy from wind turbines at the remote end) without explicit communication of frequency data and the headroom required in power converters (turbine and HVDC) to accommodate this service. The protection schemes that identify and isolated faulty equipment are also impacted by use of asynchronous generation since their power converter interfaces offer much lower short-circuit currents that are difficult to discriminate. The problem will be analysed in detail and re-engineering of the protection schemes proposed. A series of technical challenges that arise from widespread use of HVDC to connect remote renewable resources will also be studied. First is the operation and protection of multi-terminal HVDC that would allow meshing of DC routes to form more secure networks providing that the power flow and fault management issues can be addressed. Second is the reassessment of wind farm collection networks to eliminate potentially wasteful energy conversion stages. Third is innovation in HVDC converter design to make cost-effective the supply (or in-feed) of small fractions of power at intermediate points.The main programme of work will be conducted by post-doctoral research associates in China and the UK each of whom will have a 3-month placement in the other country to deepen the interaction between the research teams. In China, PhD projects will also be arranged around the key research themes. In the UK, the work will be allied to the existing PhD cohorts in the universities. A steering committee that meets alternately in China and the UK will manage the programme.The key outputs will be the analysis methods that are developed to assess the problems identified (and which are useful to grid system operators); proposals for engineering solutions (useful to system operators and equipment vendors) and verification of these proposals through scaled laboratory test systems and real-time simulation.