附加励磁阻尼控制抑制多模态SSR的机理及其关键技术

一些新建的大型煤电基地由于采用较高固定串补度的厂对网远距离大容量输电模式,所引发的多模态次同步谐振(SSR)正成为威胁机组安全和电网稳定的现实难题.以上都电厂串补输电工程(二期)为例,阐述多模态SSR的发生机理,分析采用附加励磁阻尼控制(SEDC)抑制多模态SSR的基本原理及其相对于其他措施的特点和优势,并重点探讨SEDC研发中面临的关键技术问题及其解决思路,为中国自主研发和应用SEDC设备解决SSR问题奠定基础.     

火炮漏磁检测仪设计的研究

The parts ofgun often create crack when used for aperiod, in order to avoid accident caused by crack, wem ustdetect it periodically, this is very im portant for thesafely operation and the safety of the operator. Them agnetic flux leakage (M FL) detecting m ethod is verysensitive to the crack on ferrom agnetic m aterials, andwith low cost and sim ple arts and crafts. So it is verywidely used in the crack detection for gun.The principle of M FL non-destruction is as follow s.The gun ' s part…     

掺入SiO2纳米颗粒对厚膜ZnO气敏传感器气敏性能的影响

利用丝网印刷技术,制备出掺入SiO2和未掺入SiO2的ZnO厚膜气敏传感器,测试对甲醇和乙醇的气敏性能,并用场发射扫描电子显微镜(FESEM)来分析表征气敏膜的微观形貌。结果表明SiO2的掺人有效地抑制了ZnO晶粒的长大。在工作温度为400～450℃时,SiO2的掺入显著提高了ZnO厚膜气敏传感器对甲醇和乙醇的敏感度,...     

Verification for Particle Size Distribution of Ultrafine Powders by the SAXS Method

The Dividing Distribution Function (DDF) method is one of the methods by which the particle size distribution of ultrafine powder can be evaluated from its small-angle X-ray scattering (SAXS) data. In this paper, the particle size distributions of many different samples were reported, and the reliability of DDF was proved by TEM. For a series of samples, the specific surfaces were measured by the BET method, and also calculated from their particle size distributions obtained by SAXS determination. The two sets of results are systemically compared.     

上都电厂SEDC提高次同步扭振阻尼的现场试验

在上都电厂4号机上进行了附加励磁阻尼控制（SEDC）提高次同步扭振阻尼的现场试验，介绍了试验的基本原理、运行环境、主要内容和试验数据分析。试验结果表明:采用励磁注入法可安全、可靠地激发轴系次同步扭振并精确测定其特征频率，SEDC能有效改善各扭振模态的阻尼且不会对励磁系统常规调节功能（自动电压调节器/电力系统稳定器）造成不利影响。作为中国第1次以现场试验方式实证SEDC提高次同步扭振模态阻尼的效果，为自主研发和应用SEDC抑制次同步振荡/谐振奠定了基础。     

Synthesis and compressive behavior of Cr2GeC up to 48 GPa

M_n+1AX_n compounds have gathered huge momentum because of its exciting properties. In this paper we report the synthesis of ternary layered ceramic Cr₂GeC, a 211 M_n+1AX_n compound by hot-pressing. Scanning electron microscopy and X-ray diffraction have been employed to characterize the new synthesized phase. High-pressure compressibility of Cr₂GeC were measured using diamond anvil cell and synchrotron radiation at room temperature up to 48 GPa. No phase transformation was observed in the experimental pressure range. The bulk modulus of Cr₂GeC calculated using the Birch–Murnaghan equation of state is 169 ± 3 GPa, with K′ = 3.05 ± 0.15.     

电网不平衡下SMES变流器动态演化控制策略研究

针对超导磁储能(SMES)变流器在电网电压不平衡下的工作情况,提出一种新型非线性控制策略,即动态演化控制(DEC)。该控制方法相较于传统PI控制能有效地减小SMES因电网电压不平衡而产生的三相电流畸变以及有功、无功功率产生的二次谐波。文中根据电网不平衡下SMES变流器的工作情况设置三个工作目标;建立了基于DEC的不平衡控制方程,并在Simulink中搭建模型进行仿真分析。通过与传统PI控制作对比,DEC控制具有更强的鲁棒性,更快速的响应能力,理论分析和仿真结果验证了该控制策略的可行性和有效性。     

预装式移动智能开关站的研究和实践

为满足某些地区或季节性急速增长的用电负荷,以及电网故障应急、电网改造期间负荷转供等特殊情况,需要行之有效的稳定负荷转供技术.预装式移动智能开关站具有设备模块化、预装化、移动方便等特点,整体性好,运行安全可靠,使用灵活.只要在有合适电源的地方,就可以较少的工作量、在较短时间里完成移动开关站的建设,以实现负荷转供,确保用户不间断供电.     

煤矿采空塌陷区危险性预测模型构建及其防治措施

采矿因素、地质因素等因素影响煤矿矿井采空塌陷区危险性预测结果,为了获取准确的煤矿采空塌陷区危险性预测结果,构建煤矿矿井采空塌陷区危险性预测模型。选取某省煤矿矿区作为研究区域,选取下沉系数与水平移动系数作为构建煤矿采空塌陷区危险性预测模型的参数,采用T-S模糊方法构建煤矿矿井采空塌陷区危险性预测模型,通过修正预测模型的模糊子集隶属函数更新预测模型,提升煤矿矿井采空塌陷区危险性预测精度。所构建模型输出煤矿矿井采空塌陷区危险性预测结果为中等,针对预测结果提出采用合理的采煤方式、合理避让、加强边坡监测3项煤矿矿井采空区塌陷防治措施,为煤矿矿井开采后防治采空区地面塌陷提供指导。     

Statistical analysis and adaptive technique for dynamical process monitoring

Multivariate statistical process monitoring (MSPM) methods based on two-dimensional dynamic kernel PCA (2-D-DKPCA) and two-dimensional dynamic kernel Hebbian Algorithm (2-D-DKHA) are proposed. First, a nonlinear batch process monitoring scheme based on 2-D-DKPCA is proposed. Its basic idea is to use KPCA to depict the both within-batch dynamics and batch-to-batch dynamics. However, the proposed 2-D-DKPCA needs to store the whole kernel matrix and calculate all nonlinear components. Kernel matrix will thus become extremely huge when the numbers of successive batches and samples are large. Then, kernel Hebbian Algorithm (KHA) is introduced to 2-D-DKPCA to construct 2-D-DKHA. KHA can extract adaptively nonlinear principal components without storing and manipulating the whole kernel matrix and only calculate the principal components. Thus, proposed 2-D-DKHA has the ability of monitoring complex batch processes. The 2-D-DKPCA and 2-D-DKHA are first proposed in this article. Also, from the proposed 2-D method, it is easily to obtain the 1-D algorithm.