高比例新能源特高压交直流典型算例系统(二):频率及振荡问题算例系统

算例系统源自对实际电力系统的抽象和简化,能反映实际系统存在的各类稳定特征,是开展电力系统特性分析研究的重要基础。近年来,随着特高压直流和新能源的快速发展,电力系统出现宽频振荡等新型稳定问题,同时传统的电压、功角、频率等稳定问题加剧,而我国电力行业尚未发布适用于研究高比例新能源特高压交直流系统的典型算例系统。该文作为典型算例系统系列之二,聚焦频率及振荡稳定问题,构建了3种算例系统,包含直流送端孤岛运行、高占比水电经直流外送以及高比例新能源汇集并网不同典型场景,详细描述了网络拓扑结构、新能源、直流、负荷等模型及参数,以便研究者进行数据搭建及使用。通过仿真验证了算例系统模拟频率及振荡特性的有效性,可支撑高比例新能源特高压交直流混联系统机理探究及算法验证。

高比例新能源特高压交直流典型算例系统(一):电压及功角稳定算例系统

算例系统源自对实际电力系统的抽象和简化,能反映实际系统存在的各类稳定特征,是开展电力系统特性分析研究的重要基础。近年来,随着特高压直流和新能源的快速发展,电力系统出现宽频振荡等新型稳定问题,同时传统的电压、功角、频率等稳定问题加剧,而我国电力行业尚未发布适用于研究高比例新能源特高压交直流系统的典型算例系统。该文作为典型算例系统系列之一,聚焦电压及功角稳定问题,构建了3种算例系统,包含大规模纯新能源汇集通过交流外送、新能源与常规电源打捆通过交直流外送、大容量直流馈入受端负荷中心不同典型场景,详细描述了网络拓扑结构、新能源、直流、负荷等模型及参数,以便研究者进行数据搭建及使用。通过仿真验证了算例系统模拟电压及功角稳定特性的有效性,可支撑高比例新能源特高压交直流混联系统机理探究及算法验证。

典型中低压微电网算例系统设计

针对国内配电网的实际现状,设计了一个典型的中压微电网和低压微电网算例系统。系统中考虑了光伏发电、风力发电、蓄电池等多种分布式电源的接入方式,具有结构灵活、运行方式多样等特点,能够满足微电网各种问题研究的需要。利用商业化的仿真软件DIgSILENT对这一算例系统进行了相关测试,仿真结果验证了算例系统的合理性。

Modified Projective Synchronization of a New Hyperchaotic System via Nonlinear Control

In this paper, a nonlinear control scheme of two identical hyperchaotic Chert systems is developed to realize their modified projective synchronization. We achieve modified projective synchronization between the two identical hyperchaotic systems by directing the scaling factor onto the desired value. With symbolic computation system Maple and Lyapunov stability theory, numerical simulations are given to perform the process of the synchronization.

Artificial neural network modeling of water quality of the Yangtze River system:a case study in reaches crossing the city of Chongqing

An effective approach for describing complicated water quality processes is very important for river water quality management. We built two artificial neural network(ANN) models,a feed-forward back-propagation(BP) model and a radial basis function(RBF) model,to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing,P. R. China. Our models used the historical monitoring data of biological oxygen demand,dissolved oxygen,ammonia,oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models,the RBF model calculates with a smaller mean error,but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the structures of neural network water-quality models.

Research and implementation of a personalized book recommendation algorithm --Taking the library of Jinan University as an example

Abstract： Taking the basic data and the log data of the various businesses of the automation integrated management system of the library in Jinan University as the research object this paper analyzes the internal relationship between books and between the books and the readers, and designs a personalized book recommendation algorithm, the BookSimValue, on the basis of the user collaborative filteringtechnology. The experimental results show that the recommended book information produced by this algorithm can effectively help the readers to solve the problem of the book information overload, which can bring great convenience to the readers and effectively save the time of the readers＇ selection of the books, thus effectively improving the utilization of the library resources and the service levels.