运行性能优化系统在火电厂600 MW机组上的应用

简述了北仑电厂二期600MW机组的基于DCS系统的运行性能优化系统。通过对机组运行参数及性能参数进行耗差分析,试系统对运行人员进行实时的调整指导,使机组运行的经济性得以提高,有利于电厂的节能降耗。

基于差动调速的风氢联合发电系统容量配置与运行性能

差动调速型风电机组可在无需整流-逆变装置下与电网友好连接,为大规模风电并网和特大型风电装备的研制提供了新的技术途径。面向国家“双碳”需求,以提高风电消纳能力及并网运行稳定性、经济性为导向,提出了一种基于差动调速的风氢联合发电系统方案,并分析了其基本结构和调速原理,构建了关键单元的数学模型。为确保风氢联合发电的系统稳定、经济运行,在综合考虑风电出力及负荷需求等不确定性因素条件下,建立了制氢储能系统的容量优化模型;在保持高水平风能利用的条件下,完成了制氢储能系统的容量配置,并揭示了关键参数对容量配置的影响规律。搭建了所提风氢联合发电系统的仿真模型,在不同风速条件下,验证了所提方案的原理可行性及其在运行性能上的优越性。

我的系统一干二净

也许你是新软件的尝鲜一族，乐意在自己的系统中安装试用各类软件的最新版本；也许在使用诸如Word之类的软件后发现它们留下很多的垃圾文件，久而久之占用大量的磁盘空间，影响系统运行性能；也许你发现在使用了超级兔子或Norton CleanSweep之后，系统中还是留有一些欲除之而后快的垃圾文件……你应该试试Advanced Uninstaller。

Operation Performance of Air Source Heat Pump System for Space Heating in Tianjin

An air source heat pump system (ASHPS) used in an office building is set up and studied experimentally. Its operating performance in winter is evaluated based on test data and a comparative discussion is given on the effect of climate conditions and heating load ratio on the operation behavior. Then heating capacity variation caused by evaporator frosting is analyzed as well. Finally, the defrosting parameters and the technical feasibility are studied for a constant heating demand. The experimental results indicate that both the outlet water temperature drop and the system COP should be taken into account when setting defrosting parameters, and ASHPS is a viable technology for space heating and hot-water production in winter in Tianjin, which can maintain the room temperature above 19 ℃ when the outdoor temperature is -2 ℃.

Economic Load Dispatch with Daily Load Patterns Using Particle Swarm Optimization

ELD （economic load dispatch） problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based PSO （particle swarm optimization） algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as QP （quadratic programming）, and GA （genetic algorithm）.

虚拟内存到底应该怎么设？

使用Windows的朋友，很多人都知道虚拟内存这个东西。顾名思义，它是“虚拟”的内存。内存少，Windows“跑不动”，这是“地球人都知道”的事实。同样，虚拟内存容量设置不合理，也会对系统运行性能有很大影响。少了是不行，总是会弹出窗口来报警。那是不是越多越好?

Featured services and performance of BDS-3

BeiDou Global Navigation Satellite System(BDS-3)not only performs the normal positioning,navigation and timing(PNT)functions,but also provides featured services,which are divided into geostationary orbit(GEO)and medium earth orbit(MEO)satellite-based featured services in this paper.The former refers to regional services consisting of the regional short message communication service(RSMCS),the radio determination satellite service(RDSS),the BDS satellite-based augmented service(BDSBAS)and the satellite-based precise point positioning service via B2b signal(B2b-PPP).The latter refers to global services consisting of the global short message communication service(GSMCS)and the MEO satellite-based search and rescue(MEOSAR)service.The focus of this paper is to describe these featured services and evaluate their performances.The results show that the inter-satellite link(ISL)contributes a lot to the accuracy improvement of orbit determination and time synchronization for the whole constellation.Compared with some other final products,the root mean squares(RMS)of the BDS-3 precise orbits and broadcast clock are 25.1 cm and 2.01 ns,respectively.The positioning accuracy of single frequency is better than 6 m,and that of the generalized RDSS is usually better than 12 m.For featured services,the success rates of RSMCS and GSMCS are better than 99.9% and 95.6%,respectively;the positioning accuracies of single and dual frequency BDSBAS are better than 3 and 2 m,respectively;the positioning accuracy of B2b-PPP is better than 0.6 m,and the convergence time is usually smaller than 30 min;the single station test shows that the success rate of MEOSAR is better than 99%.Due to the ISL realization in the BDS-3 constellation,the performance and capacities of the global featured services are improved significantly.

Numerical Analysis of Chevron Nozzle Effects on Performance of the Supersonic Ejector-Diffuser System

The supersonic nozzle is the most important device of an ejector-diffuser system.The best operation condition and optimal structure of supersonic nozzle are hardly known due to the complicated turbulent mixing,compressibility effects and even flow unsteadiness which are generated around the nozzle extent.In the present study,the primary stream nozzle was redesigned using convergent nozzle to activate the shear actions between the primary and secondary streams,by means of longitudinal vortices generated between the Chevron lobes.Exactly same geometrical model of ejector-diffuser system was created to validate the results of experimental data.The operation characteristics of the ejector system were compared between Chevron nozzle and conventional convergent nozzle for the primary stream.A CFD method has been applied to simulate the supersonic flows and shock waves inside the ejector.It is observed that the flow structure and shock system were changed and primary numerical analysis results show that the Chevron nozzle achieve a positive effect on the supersonic ejector-diffuser system performance.The ejector with Chevron nozzle can entrain more secondary stream with less primary stream mass flow rate.