综合能源网络统一建模及其应用(一):时域二端口模型

Unified Modeling of Integrated Energy Networks in Time Domain and Its Applications(Ⅰ): Two-port Models in Time Domain

综合能源网络的统一建模通过构造相同数学形式的能流模型从而降低求解难度,有利于实现电气热系统标准化运行分析技术。该文基于源荷二端口网络等值的思想构建了描述电气热能流传输与分布特性的综合能源网络时域统一模型。首先,采用中心隐式差分格式将电气热网络统一方程代数化,并利用差分网格的对称下三角特性提出基于初始和边界条件传递矩阵的建模方法,推导支路首–末端状态量的解析表达式,进而建立时域支路统一模型。接着,结合支路统一模型和拓扑关联方程,构造基于广义时域导纳矩阵的网络统一模型,最后根据电气热系统的运行特征推导各状态量的时域二端口方程。算例分析表明,文中方法准确性高,计算效率远高于传统差分方法。

The unified modeling of integrated energy networks(IEN) reduces the solution difficulty by constructing the energy flow model with the same mathematic form, which is beneficial for realizing the standardized operational analysis technology. Based on the concept of source-load two-port network equivalence, a unified model in time domain that describes the transmission and distribution features of multi-energy flow was proposed in this paper. Firstly, the central implicit scheme was employed to transform the unified equations of IEN into algebraic equations. The analytical function of variables along the branch was further constructed to formulate the branch model, where the transfer matrixes of initial/boundary conditions were built based on symmetrical lower triangular properties of differential grids. Then, the branch model and topological equations were combined to establish the unified network model based on the generalized admittance matrix of IEN, and the two-port models in time domain were finally derived according to the operational features of different energy networks. Numerical simulations indicate the accuracy of the proposed model and its superior efficiency compared with the traditional difference method.