大功率缺失下的动态频率响应运行调度理论

In the frequency stability controlling under high-power deficiency, the capability of frequency response of the power system would be misjudged from the static point of view. And, the consequences caused would be impossible to foresee. It makes the issue above more prominent that both UHVAC and UHVDC hybrid power grid and high proportion of clean energy integration could lead to the frequency response capability deficiency. Except for the post-response electrical parameter, the pre-response electrical and thermo-motive parameter should also be taken into consideration from the dynamic point of view. In addition, temporal and spatial distribution characteristic of frequency deviation and system operation pattern should also be taken into account, because they could influence the frequency response characteristic. Hereby, a mathematic model which can predict characteristic of dynamic frequency response accurately should be established. On base of risk analysis, the reserve theory of frequency response which has taken into account the comprehensive effect of some active power balance control methods could determine part or whole reserve configuration of grid in the operation planning and scheduling exactly. On-line analysis method of operation risk of frequency response reserve which is based on pattern recognition technique, and control strategy of frequency response which is based on adaptive adjustment of response deadband could realize a more precise control effect by fully exploring and rationally making use of the frequency response capability of conventional units. The proposed control performance assessment criteria of frequency response considering dynamic response characteristic could make evaluation result more objective and reasonable.

在大功率缺失下的频率稳定控制中，依据静态角度分析会导致对系统所具有频率响应能力的误判，后果不可想象，特别是在现今特高压交直流电网混联和高比例清洁能源并网共同造成频率响应能力短缺的局面下，该问题更加凸显。从动态特性入手，从仅关注响应后的电气量到综合计及响应前后的电气和热动参数，从静态分析到考虑频差时空分布特性和系统运行方式等对系统频率响应特性的影响，构建可精确表征机组和系统动态频率响应特性的数学模型。据此，基于风险分析考虑多种有功平衡控制手段综合作用效果所提出的频率响应备用理论，可较为准确确定运行规划和计划中电网局部或整体备用配置；基于模式识别技术的频率响应备用运行风险在线分析方法和基于响应死区自适应调整的频率响应控制策略，可充分发掘与合理运用常规机组的频率响应能力，实现更为精准的控制；所提出计及动态响应特性的频率响应控制性能评价标准，可保证评价结果更为客观和合理。

随着特高压交直流电网的纵深发展和新能源渗透率的不断提高，电力系统频率稳定态势愈发严峻，频率响应矛盾日益突出。在此背景下，本项目在国内首次提出并率先开展了动态频率响应研究，围绕运行建模、监视、控制和评价，提出“大功率缺失下的动态频率响应运行调度理论体系”，并取得了相应研究进展，可为动态频率响应的后续研究提供参考和借鉴。具体包括：.(1) 在频率响应建模中，针对火电机组，建立了计及蓄热动态的低阶频率响应模型；针对水电机组，建立了计及水锤效应的混流式水轮机组动态频率响应模型。.(2) 在频率响应监视研究中，从系统统一频率视角，提出了大功率缺失下频率最低点估计的低阶仿真建模和解析建模方法；从分布频率视角，提出了频率响应的两机等值电力系统模型的建模及闭式解求解方法。.(3) 在频率响应控制中，系统层面，构建了紧急情况下基于电网频率时空分布特性的主动频率响应控制框架，提出了非紧急情况下动态死区频率响应自适应控制策略；元件层面，针对储能元件提供频率响应的实时运行控制过程提出了动态阈值能量管理策略。.(4) 在频率响应评价中，面向常规火电机组，提出了动态频率响应控制性能评价指标参量计算方法；面向新能源高占比的特高压电网，提出了基于运行安全的频率控制模式及其性能评价方法。.本项目的研究为动态频率响应运行调度提供了有效的建模思路、监视方法、控制策略和评价依据，可为大功率缺失下电网的处置能力的提升和电力安全供应的保障提供理论依据和参考。