面向大规模风电消纳的电、热储能协同规划

According to spatiotemporal characteristics of wind power curtailment situations appeared presently in our country, this project will break through a mutually independent way in which electric power systems and heat systems are operated and realize coordinative planning of multi-type energy storage systems (ESS) that are respectively equipped in electric power systems and heat systems for storing electric and thermal energy. So that large scale wind powers can be accommodated with high efficiency. In order to reduce optimal variables in the formulations of ESS coordinative planning, heat station and heat consumers are aggregated into an aggregated model of heat characteristics that will be considered as a controllable heat load in heat systems. Secondly, a mixed time scale time sequence production method is presented to simulate the electric power systems and heat systems simultaneously during planning years. Based on the time sequence simulations of electric power systems and heat systems, a two-level planning model is presented to realize coordinative planning of multi-type ESS. Multi-period time sequence coupling characteristics of heat systems are modeled and considered as boundary conditions in simulating the heat systems. At last, a linearized associated power flow model of electricity and heat is presented according to unified modeling of electric and thermal coupling elements and model linearization of the heat systems. So that an associated power flow calculation of electricity and heat with high efficiency can be realized. In addition, equivalent aggregation of electric power systems and heat systems, equivalence transformation of complex constraints and rolling optimization are employed to accelerate solution of the coordinative planning model. The expected results of this project can not only provide theoretical support for coordinative planning of multi-type ESS, but also promote wind power accommodation.

针对我国当前“弃风”形势的时空特性，项目打破电、热系统相对独立的现状，对电、热系统中分别用于储电与储热的多类型储能进行协同规划，促进风电接纳。为缩小优化规模，对换热站与供热用户的热特性进行等效聚合，作为一次热网的可控热负荷。接着，针对电、热系统物理特性，提出混合时间尺度时序生产模拟方法，对电、热系统在规划水平年内的运行状况进行时序优化，并以此为基础建立面向电、热储能协同规划的双层优化模型。电、热系统时序优化中，对热力系统的多时段时序耦合特性进行建模，作为热力系统的运行边界条件；最后，在电、热耦合元件统一建模与热力系统模型线性化的基础上，建立线性化电、热联合潮流模型，实现电、热系统联合潮流的高效分析，并采用电、热系统等效聚合、复杂约束等价变换与滚动优化实现电、热协同规划模型的高效求解。项目研究成果可为我国开展电、热多类型ESS协同规划，解决大规模“弃风”限电问题提供重要理论支持。

大力发展风电，是促进新型电力系统建设的重要举措之一。打破电、热系统相对独立的现状，在充分考虑热力系统热特性的基础上，对电、热系统中分别用于储电与储热的多类型储能进行协同规划，可有效提升系统风电接纳能力，支撑大规模风电并网。在此背景下，项目进行了如下研究。首先，对热源、热网与热负荷的热特性进行了分析与建模，形成了完善的热力系统模型。为缩小热网模型中的变量规模，对换热站与供热用户的热特性进行了等效聚合，并将其作为一次热网中的可控热负荷。对换热站等效热负荷模型来说，只要其在任意时间窗内的热功率满足给定约束，所有终端热用户的热舒适度便可满足要求。其次，建立了基于双层优化的电、热储能协同规划模型，其中，下层优化模型为基于混合时间尺度的电、热系统时序模拟模型，对电、热系统的时序运行工况进行优化，为上层优化提供依据。相对于电力系统，由于工况参数变化缓慢，热力系统时序模拟采用的时间尺度可适当延长。研究表明，热力系统规模越大，适合的时间尺度越长，一般在半小时至两小时之间。此外，热力系统时序模拟时，热力系统的多时段时序耦合特性主要体现为换热站等效热负荷的时序耦合特性，而热网运行工况的时序耦合特性可以忽略。最后，对电、热储能协同规划模型的高效求解方法进行了研究。电、热储能协同规划模型为双层优化模型，可通过上、下层优化模型的迭代求解获得整个规划模型的最优解。上层优化模型为无梯度优化问题，采用最优模式搜索求解；下层优化模型为复杂约束下的大规模混合整数线性规划问题，是电、热储能系统协同规划模型高效求解的难点。为降低求解计算量，将电、热系统等效聚合为若干子系统，并对各子系统内部同类型火电机组、热电联产机组与热源进行了等效合并，有效减少下层优化问题中的优化变量和约束的数目。此外，提出了面向子系统联络线交换功率的两阶段迭代优化方法，实现了联络线交换功率的快速优化，支撑了下层优化问题的高效求解。