计及暂态稳定约束和群特性的主动解列策略研究

Controlled islanding of a power system is an efficient corrective measure for limiting system blackouts after a large disturbance has occurred. It limits the occurrence and consequences of blackouts by splitting the system into a group of smaller, islanded power systems, or islands. It is usually considered as a constrained combinatorial optimization problem. However, the mechanism of transient stability during islanding process has not been clarified very well and the transient stability constraints for islanding have not been formulated and included into the controlled islanding modeling. The existing methods only consider steady-state and quasi-steady-state constraints and make strong but unrealistic assumptions for transient stability. These unrealistic assumptions may lead to unsuccessful islanding. To solve this problem, this project plans to run the transient stability analysis during islanding process thoroughly and then elaborate the information of transient stability constraint to guide the strategy determination. Structure preserving energy function and Extended Equal Area Criteria (EEAC) are combined with time-domain simulation to analyze the islanding process quantitatively. The Impact of islanding boundary and islanding timing on transient stability of islands formed will be explored and the feasible regions of such key parameters will be formed and studied. However, the information of such constraint is extracted from case-by-case study and is difficult to be included into model. The coherency and group property among islanding strategies will be defined and investigated. The useful information of group properties will be introduced to guide islanding strategies determination. It is anticipated that this research will contribute to the optimization decision of controlled islanding, and also to the improvement of self-healing and self-adaptive of smart grid.

主动解列在电网无法继续完整运行时将电网分解为多个孤岛运行，限制和避免大停电的发生。由于解列策略的暂态稳定约束还不明确，无法引入问题模型，目前的研究主要考虑稳态和准稳态约束，利用强假设规避暂稳约束，可能造成孤岛失稳、解列失败。本项目以暂态功角稳定为突破口，首先研究解列策略对暂态稳定的影响以及暂态稳定对解列策略选取范围的约束，以基于能量函数和EEAC的混合法定量分析解列断面和解列时刻等关键参数变化对孤岛稳定性的影响；研究解列断面和解列时刻的参数域分布，建立其暂态稳定约束条件；然后研究挖掘解列策略之间的同调性和群特性，在不同解列策略对孤岛稳定性影响的个体差异中寻找群体共性，提取有利于孤岛稳定的解列策略群特性；最后研究如何将群特性信息引入主动解列的问题建模和决策过程，并完善解列过程暂态稳定问题研究的理论解释和理论支撑。通过本项目的研究，实现考虑暂态稳定的主动解列决策，提高智能电网的自愈性和自适性

面向交直流混联和大规模可再生能源接入引起的安全防御问题，围绕电力系统主动解列开展系统性研究，提出了适用于主动解列的发电机分群在线识别方法，通过对系统轨迹的判断，分别在稳定平衡点和不稳定平衡点处线性化，根据线性化后系统的特征值和特征向量进行分群，同时适用于大扰动和小扰动；开创性的对主动解列时刻开展研究，利用暂态能量函数对主动解列的过程进行稳定性的量化分析，将动态稳定约束引入决策过程，引入了可行解列时刻的概念并提出了基于暂态能量函数的可行解列时刻计算方法。率先开展低惯量系统主动解列的研究，利用摄动理论研究了高比例可再生能源并网引起的惯量降低给发电机分群带来的影响，并提出了适用于低惯量电力系统的谱聚类主动解列算法，为未来高比例可再生能源系统的分析奠定基础。完善和扩展了主动解列的理论研究体系，实现了适应高比例可再生能源接入和交直流混联的大电网主动解列优化决策。