有源配电网接地方式与接地故障自愈控制的基础问题

Compared with traditional distribution network, the grounding mode of active distribution network (main distribution network and distributed generation DG) and its self-healing technology of single phase earth fault become much more complex. The existing research and conclusions are grossly inadequate, which restrict the grid-connection of DGs. Fault current and overvoltage characteristics of single phase earth fault in different fault-stages for the active distribution networks with different grounding mode will be anayzed in this project. The adaptability and the acceptable capacity of existing distribution networks for DGs with different grounding mode will be anayzed under the constraints of existing network's insulation and relay. The optimized grounding mode of active distribution network free from the constrait of existing distribution network will also be proposed. And then the self-healing technology system of single phase earth fault for the non-solidly grounding active network will be established, which covers the entire fault-cycle including fault prevention, fault self-recovery, reduction of the power cut loss, avoiding damage of the fault overvoltage and so on. The transient characteritics of single phase earth fault and the basic theory of its self-healing technology such as insulation monitoring based on instantaneous fault information, arc-suppression and overvoltage control based on flexible compensation device and adaptive isolation will be anayzed. Finally, simulations and field experiments will be used to verify the validity and feasibility of analysis above. Research results are expected to solve basic theories and key issues of the neutral grounding method seclection and the single pahse earth fault self-healing technology in the active distribution network, and improve the power supply reliability and intelligent level of active distribution network.

相比常规配电网，有源配电网（分别指主网与分布式电源DG）的接地方式及其单相接地故障自愈技术将更为复杂，现有研究及结论均严重不足，已成为制约DG并网的一个重要因素。 项目拟针对主网与DG不同接地方式组合的有源配电网，分析单相接地后不同故障处理阶段的故障电流与过电压特征；考虑国内现有配电网绝缘与继电保护约束条件，分析其对不同接地方式DG的适应能力；给出脱离现有条件约束的有源配电网优化接地方式。建立预防故障发生、促使故障自恢复、减小故障停电影响、避免过电压危害等涵盖整个故障周期的有源配电网小电流接地故障自愈技术体系，研究接地故障暂态特征以及利用瞬时性故障信息的线路绝缘监测、基于有源补偿装置的消弧与电压控制、自适应隔离等主要自愈技术的基本原理。利用数字仿真和现场实验验证。 研究成果有望解决有源配电网中性点接地方式选择和接地故障自愈控制的基础理论及关键问题，提高有源配电网供电可靠性和智能化水平。

相比常规配电网，有源配电网接地方式（分别指主网与分布式电源DG的接地方式）及其单相接地故障自愈技术将更为复杂，现有研究及结论均不足，已成为制约DG并网的一个重要因素。.项目给出了有源配电网接地方式可能的组合，分析了不同条件下系统接地方式的转变问题；分析了主网和DG不同接地方式组合的有源配电网单相接地故障特征；从接地保护灵敏度、供电可靠性和过电压角度给出了有源配电网主网和DG接地方式最优组合的建议，即系统采用小电流接地方式，并配以选择性快速的隔离技术。对于主网接地方式已定的配电网，若主网采用小电流接地方式，DG应采用不接地方式；若主网采用小电阻接地方式，DG应配有中性点接地电阻，并网运行时DG采用不接地方式，脱网运行时DG通过电阻接地。.建立了涵盖接地前避免故障发生、接地时促进故障自恢复、永久接地时检测与隔离的有源配电网小电流接地故障全周期自愈技术体系；给出了满足现场应用条件的实用型有源电压消弧、电流消弧方法；分析了已有接地故障保护方法在有源配电网中的适应性，对原有方法进行了完善改进；针对小电流和小电阻接地系统，提出了一系列高阻接地故障检测保护方法；建立了能够反映实际拉弧过程的控制论电弧模型，分析了间歇性接地故障熄弧后电压恢复特征以及重燃后故障点电流暂态与过电压特征；给出了顾及过电压、线路绝缘状况、负荷重要程度的小电流接地故障自适应隔离方案；完成了小电流接地故障类型及成因辨识；提出了不对称电压有源控制方法。最后，完成了数字仿真、现场实验验证及技术推广应用。.项目部分成果已在现场获得应用，解决了有源配电网中性点接地方式选择和接地故障自愈控制的基础理论及关键问题，有助于提高有源配电网供电可靠性和智能化水平。.项目发表学术论文43篇（SCI检索2篇，EI检索21篇），录用论文12篇，出版学术专著2部，申请国家发明专利13项，获得国家发明专利授权5项，获得省部级科技奖励2项；培养博士研究生1名、硕士研究生21名。