Enhanced Renewable Integration through Flexible Transmission Options (ERIFT)

中国安装风电场的速度比其他任何国家都快，英国在海上风电场的部署方面处于领先地位。在通过(电力)长电缆或架空直流线路连接偏远地区的可再生能源方面，两国都将面临挑战，在控制高比例异步发电的系统方面也将面临挑战。该提案确定了共同的技术挑战领域，并制定了一项联合方案，以分析问题和评估可能的解决办法。充分开发潜在的输送能力至关重要；在中国，这是从西部/中部水电资源到东部/沿海城市，在英国是从苏格兰和北海的风能资源到南部负荷中心。一组交流和直流线路的可实现传输能力完全取决于不同负载条件下系统控制的安排(这会影响稳定性约束)，以及配置的风险概况(会因为冗余和安全原因而影响卸载)。我们将研究交流、直流和FACTS元件的协调控制，以优化传输能力，并将开发工具来支持运营商决策，包括风险分析。一个国家的输电系统在高比例异步发电的情况下运行，惯性很小，因此需要合成显式频率响应来保持系统频率在一定范围内。将调查两个具体方面：在不明确传递频率数据的情况下，通过直流链路提供频率响应服务的能力(来自远端风力涡轮机的动能)，以及电力变流器(涡轮机和高压直流输电)为适应这一服务所需的净空空间。识别和隔离故障设备的保护方案也受到使用异步发电的影响，因为它们的电源转换器接口提供的短路电流要小得多，很难区分。将详细分析这一问题，并提出重新设计保护方案的建议。还将研究广泛使用高压直流输电连接偏远的可再生资源所产生的一系列技术挑战。首先是多端高压直流输电的运行和保护，这将使直流线路联网形成更安全的网络，前提是潮流和故障管理问题能够得到解决。第二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。第三是高压直流换流器设计的创新，使中点的小部分电力供应(或馈入)具有成本效益。主要工作计划将由中国和英国的博士后助理进行，他们每人将在对方国家工作3个月，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队伍结盟。中国和英国轮流召开的指导委员会将管理该项目。主要产出将是为评估所发现的问题而开发的分析方法(以及对电网系统运营商有用的方法)；工程解决方案的建议(对系统运营商和设备供应商有用)，以及通过大规模实验室测试系统和实时模拟对这些建议进行验证。

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.