基于半波长交流的新能源孤岛接入与超远输送技术研究

With the increase of operational HVDC transmission projects and the development of renewable energy islands , the current pattern for trans-regional transmission of renewable energy, which is based on HVDC/UHVDC transmission technology, has already encountered the bottleneck of renewable energy integration and peak load regulation barrier at the sending-end grid and 'strong DC and weak AC' dilemma at the receiving-end grid. Therefore, it is urgent to carry out the research on novel technology for large capacity and long distance power transmission with fine adaption to renewable energy grid-connection, transmission and consumption. This project proposes the innovative trans-regional transmission pattern and technological scheme for renewable energy islands in sending-end grid , and in this scheme the renewable generation is directly connected and transmitted to the receiving end via half-wavelength AC lines. Further, the technological feasibility, advantages and future prospects in application of the proposed scheme will be fully studied. In addition, this project focuses on the scientific problems of ultra-long AC line, i.e. the spatial periodicity in equivalent parameters and the tight coupling of various transient characteristics on multiple time-scales, and then performs the solid research work on transient features of electro-mechanical and electromagnetic transient process for system in the proposed scheme. Besides, this project intensively involves the problems of complementary operation between the distinct features of the voltage support transference along ultra-long AC line and the current-source characteristic of renewable generation, and the collaborative control on multiple time-scales, in conjunction with the profound study of unified technology with regard to the operation and control for active/reactive power flows and voltages, as well as the countermeasures for supressing transient overvoltage and potential current, so as to put forward the detailed and viable technological schemes. The expected results from research work can provide the effective technological option for trans-regional transmission of renewable energy in China, and also provide theoretical and technological reference for the future exploration of power grid development pattern.

随着直流工程增多与新能源孤岛的开发，目前以高压/特高压直流输电为基础的新能源跨区输电模式，已经遇到了送端并网和调峰困难、受端“强直弱交”的发展瓶颈，因此迫切需要研究适宜新能源并网、输送、消纳特点的大容量、远距离新型输电技术。本项目创新提出送端新能源孤岛经半波长交流线路并网接入，同时直接输送至受端大电网进行消纳的跨区输电模式及技术方案，并深入研究其可行性、技术优势及应用前景。本项目围绕超长交流线路等值参数空间周期性以及多时间尺度暂态特性紧密耦合的科学问题，深入开展系统机电暂态和电磁暂态特性研究；围绕超长交流线路电压支撑传递特性与新能源机组电流源特性互补运行以及多时间尺度协调控制问题，深入研究有功潮流与无功电压联合调控运行技术以及暂态过电压、潜供电流抑制措施，最终提出细化可行的技术方案。预期研究成果可为我国跨区输送新能源提供有效的可选技术方案，还可为未来电网发展格局的研究提供理论和技术参考。

随着直流工程增多与新能源孤岛的开发，目前以高压/特高压直流输电为基础的新能源跨区输电模式，已经遇到了送端并网和调峰困难、受端“强直弱交”的发展瓶颈，因此迫切需要研究适宜新能源并网、输送、消纳特点的大容量、远距离新型输电技术。项目围绕超长交流线路等值参数空间周期性以及多时间尺度暂态特性紧密耦合的科学问题，获得半波长输电系统机电暂态和电磁暂态特性；围绕超长交流线路电压支撑传递特性与新能源机组电流源特性互补运行以及多时间尺度协调控制问题，获得了有功潮流与无功电压联合调控运行技术以及暂态过电压、潜供电流抑制措施，最终提出细化可行的技术方案。进而从广阔全景特性与工程狭义应用上，再认识了交流输电本质、电磁暂态与机电暂态的深度耦合关系；理清了电磁波沿线传输过程与分布式参数电路求解的一致性和内在关系。研究成果可为我国跨区输送新能源提供有效的可选技术方案，还可为未来电网发展格局的研究提供理论和技术参考。项目执行期间共发表期刊论文7篇，会议论文2篇；申请发明专利5项；撰写学术专著1册。研究成果可为我国跨区输送新能源提供有效的可选技术方案，还可为未来电网发展格局的研究提供理论和技术参考。