基于IEC 61850的继电保护纯软件测试系统

在数字化变电站中,继电保护装置或系统通过过程总线收发电气量和开关量信息,传统的模拟式测试装置和系统需要增加数模转换设备以及通信模块才能实现数字化保护装置或系统的测试.数字仿真软件由于本身就具备数字信息处理功能因而只需要增加通信程序就能够满足要求.通过分析对比,提出在MATLAB/Simulink的PSB仿真工具包的基础上,用WinPcap工具系统开发IEC 61850过程层通信功能,从而完全由软件实现了继电保护的测试系统。通过简单的仿真系统示例,验证了该方案完全满足动态、闭环、实时的测试要求.     

微量元素对废水中光合细菌生长的影响

为了强化光合细菌污水资源化效率,研究微量元素对废水中光合细菌(PSB)生长的影响,利用单因素设计法找出影响菌体产量的2个最显著的因素,以Box-Behnken设计法及响应面分析法确定了主要影响因素的最佳浓度.研究表明:0.66 mmol/L的Fe2+与0.16 mmol/L的Mg2+混合时,PSB菌体产量最高,可达到1 483.5 mg/L,COD去除率最高达到89.1%,成本最低达到0.033元/t.验证结果表明Fe和Mg组合在72 h时菌体产量达到1 380 mg/L,比空白提高了57%.微量元素Fe和Mg组合可促进废水中PSB的生长,可强化光合细菌污水资源化效率.     

基于MATLAB的变压器空载合闸瞬变过程仿真研究

变压器空载合闸投入运行时会出现一个较为复杂的电磁瞬变过程 ,对其进行工程计算很麻烦。利用MATLAB中的电气系统模块库 (PSB) ,为研究分析变压器空载合闸瞬变过程建立了系统仿真模型 ,它可以分析变压器在空载合闸瞬变过程中励磁涌流、磁通以及谐波的变化情况。本文采用这一模型进行了仿真 ,给出了仿真结果 ,为分析计算变压器空载合闸瞬变过程中的有关物理量提供了便捷而有效的手段     

非周期分量对电流互感器暂态饱和的影响

电流互感器一次侧电流中含有非周期直流分量时,会发生暂态饱和,致使二次侧电流波形失真,从而引起继电保护装置的误动或拒动。通过对非周期直流分量电流引起的电流互感器暂态饱和励磁电流进行计算,对电流互感器的暂态饱和特性进行了分析。利用Matlab仿真软件搭建了仿真实验模型,通过改变一次侧电流中非周期直流分量的方向,研究了非周期直流分量对电流互感器的饱和方向、入饱和时间的影响。最后,通过仿真比较说明了在含有不同方向非周期分量时电流互感器的暂态饱和特性。     

基于MATLAB的湖北电网次同步谐振分析

如何用一种通用的仿真工具来实时描述系统的灵活运行方式 ,具有很强的移植性是仿真问题的关键所在。从这个角度出发分析湖北电网结构及其特点 ,建立了用于研究次同步谐振问题的湖北电网简化模型 ,并利用MATLABPSB模块建立了电网次同步谐振的任意组态仿真模型。实际算例以冬季水电小发运行方式为计算水平 ,研究了湖北电网的次同步谐振问题。从仿真结果可以看出MATLAB在分析次同步谐振问题时可以快速地得到谐振频率     

基于MATLAB的湖北电网次同步谐振分析

如何用一种通用的仿真工具来实时描述系统的灵活运行方式,具有很强的移植性是仿真问题的关键所在.从这个角度出发分析湖北电网结构及其特点,建立了用于研究次同步谐振问题的湖北电网简化模型,并利用MATLAB PSB模块建立了电网次同步谐振的任意组态仿真模型.实际算例以冬季水电小发运行方式为计算水平,研究了湖北电网的次同步谐振问题.从仿真结果可以看出MATLAB在分析次同步谐振问题时可以快速地得到谐振频率.     

基于Matlab/Simulink的电路分析

为使电路分析更加直观生动,可以将Matlab软件包引入到分析过程中.以具体的直流稳态电路、交流稳态电路和一阶暂态电路为例,详述了如何分别应用Matlab语言编程的方法和直接利用可视化仿真环境Simulink/PSB设计电路模型图的方法进行建模、计算和仿真分析.通过实例说明,Matlab软件包方便、简单、调节容易、可视性好,可成功地应用于电路的仿真与分析中,在教学和研究等领域具有广泛的应用前景和一定的推广价值.     

PSB工具箱在继电保护培训体系中的应用

介绍了MATLAB中PSB(Power System Blockset)工具箱的使用及在电力系统继电保护课程体系中的应用。多数主设备的继电保护可以用MATLAB来进行时域仿真,仿真过程和结论可用于继电保护课程的教学以及相关的课程设计和毕业设计,从而加深学生对继电保护课程的理解和掌握     

A feasibility study on unsaturated flow bioreactor using optical fiber illumination for photo-hydrogen production

An unsaturated flow bioreactor with Rhodopseudomonas palustris CQK 01 was developed for photo-hydrogen production. The bioreactor developed in this work consisted of a reaction bed packed with spherical glass beads and internal optical fiber that provided uniform light distribution and achieved high light transmission efficiency. Unsaturated conditions were obtained by filling both argon and nutrient solution into the bioreactor. Experimental results demonstrated the feasibility of the biofilm formation in an unsaturated environment. With the formed biofilm, parametric studies on the photo-hydrogen production performance under different liquid flow rates and initial substrate concentrations were conducted. It was found that the performance of the bioreactor came to the optimal state at the liquid flow rate of 500 mL/h. Moreover, such a design enabled the bioreactor to be operated at relatively high glucose concentration without the substrate inhibition, yielding a good biohydrogen production performance.     

Performance of a groove-type photobioreactor for hydrogen production by immobilized photosynthetic bacteria

The biofilm technique has been proved to be an effective cell immobilization method for wastewater biodegradation but it has had restricted use in the field of photobiological H₂ production. In the present study, a groove-type photobioreactor was developed and it was shown that a groove structure with large specific surface area was beneficial to cell immobilization and biofilm formation of the photosynthetic bacteria on photobioreactor surface as well as light penetration. A series of experiments was carried out on continuous hydrogen production in the groove-type photobioreactor illuminated by monochromatic LED lights and the performance was investigated. The effects of light wavelength, light intensity, inlet glucose concentration, flow rate and initial substrate pH were studied and the results were compared with those obtained in a flat panel photobioreactor. The experimental results show that the optimum operational conditions for hydrogen production in the groove-type photobioreactor were: inlet glucose concentration 10 g/L, flow rate 60 mL/h, light intensity 6.75 W/m², light wavelength 590 nm and initial substrate pH 7.0. The maximum hydrogen production rate, H₂ yield and light conversion efficiency in the groove-type photobioreactor were 3.816 mmol/m²/h, 0.75 molH₂/molglucose and 3.8%, respectively, which were about 75% higher than those in the flat panel photobioreactor.