螺杆压缩机进气控制系统的调节

压缩机进气控制系统的调节质量好坏涉及到压缩机的工作性能,通过对蝶阀＋止回阀式进气阀所组成的进气控制系统的工作原理分析,提出了进气控制系统的调节方法和故障诊断技术,以便准确的判断故障部位和排除故障。     

塔里木盆地顺托果勒地区北东向走滑断裂带的油气勘探意义

古隆起碳酸盐岩风化壳领域是多年来塔里木盆地油气勘探发现的重要领域。近年来,在塔中、塔北古隆起之间的顺托果勒低隆、斜坡区,通过新的地震资料识别出一系列走滑断裂带,且钻井揭示其具有较好的含油气性,相继在顺南、顺托、顺北实现重大油气突破。顺托果勒地区北东向左行走滑断裂带在构造样式上具有“纵向分层变形、深部主滑移带沿走向分段变形”的特征,上奥陶统及其之上的碎屑岩层系多发育雁列式正断层,其下部对应于发育在碳酸盐岩层系的走滑断层主滑移带。受斜列侧接部位局部应力场改变的影响,走滑断裂带深部通常表现为拉分负花状、压隆正花状及平移平直状3类样式。多期活动的系列北东向走滑断裂带形成了规模较大的碳酸盐岩缝洞体系,为后期埋藏溶蚀改造形成规模储层和油气运聚均提供了有利条件,具有明显的“控储、控藏、控富”特征。在这种奥陶系发育较为齐全的低隆斜坡区呈现出沿断裂带大面积富含油气的勘探形势,具有不同于古隆起暴露剥蚀区风化壳领域的油气成藏模式,使得“塔河之外找塔河”成为可能,已初步落实轻质油资源量12×10⁸ t,将成为中石化塔里木探区“十三五”期间增储建产的主战场。     

焦作煤田区域地质背景及矿区地质特征

根据焦作地区的区域地质情况和勘查区地质特征,对焦作地区的水文、工程、煤田地质进行了简单分析,对该地区的地质构造特征进行了总结,得出该地区的煤资源开发将有光明前景的结论。     

盾构机管片安装机常见故障及其处理方法

以北京地下双线铁路隧道工程中的膨润土一气垫式泥水盾构机为例,简要介绍了盾构机的管片安装机系统,针对管片安装机常见故障进行了原因分析,并阐述了解决办法,对保证盾构施工正常运行具有一定指导意义。     

基于参数变化随机共振的碰摩故障早期检测

在随机共振基础上,提出变化系统参数检测方法,适应高频率检测信号。理论分析、数值仿真表明该方法在碰摩故障早期检测上的可靠性和有效性。     

电力系统大停电事故仿真的故障序列选择

对可能出现的故障序列进行选择,从而优化统筹各阶段的对策,对预防大停电事故具有重要的研究价值。文中通过对典型大停电事故发展的过程进行分析,在总结故障特征的基础上,提出一种可以有效考虑影响故障传播的系统负荷状况、天气条件、继电器隐藏故障等因素的方法,并快速选择出可能发生的故障序列,帮助系统规划、设计和运行人员找到容易引发大停电的线路。最后利用IEEE-RTS算例系统对该方法进行了计算验证。     

雷电定位监测系统在输电线路防雷中的应用

结合华北电网雷电定位监测系统的应用情况,介绍了其在输电线路防雷中的作用,明确了线路跳闸的主要原因及故障位置,分析了雷电活动规律,对具体线路细化,确定了防雷工作需重点注意的易击线路以及线路的易击段。通过对这些重点区域防雷配置的合理优化可以有效地降低雷击跳闸率,为系统安全稳定运行提供了保证。     

Detection of disconnection faults and double-phase short circuits in the wires of overhead transmission lines by the location method

The specific features of the detection of disconnection faults and double-phase short circuits in the wires of overhead transmission lines (OTLs), which have a tree topology with a voltage of 6–35 kV and a linear structure with a voltage of 110 kV and higher, have been studied. The techniques for interpreting reflectograms at failures in the wires of OTLs have been shown. Studies have been carried out under laboratory conditions using OTL models and under real conditions using operating OTLs.     

Disturbance observer-based backstepping sliding mode fault-tolerant control for the hydro-turbine governing system with dead-zone input

This paper investigates a backstepping sliding mode fault-tolerant tracking control problem for a hydro-turbine governing system with consideration of external disturbances, actuator faults and dead-zone input. To reduce the effects of the unknown random disturbances, the nonlinear disturbance observer is designed to identify and estimate the disturbance term. To drastically decrease the complexity of stability functions selection and controller design, the recursive processes of the backstepping technique are employed. Additionally, based on the nonlinear disturbance observer and the backstepping technique, the sliding mode fault-tolerant tracking control approach is developed for the hydro-turbine governing system (HTGS). The stability of HTGS is rigorously demonstrated through Lyapunov analysis which is capable to satisfy a tracking control performance. Finally, comprehensive simulation results are presented to illustrate the effectiveness and superiority of the proposed control scheme.     

Minimum entropy deconvolution based on simulation-determined band pass filter to detect faults in axial piston pump bearings

The fault diagnosis of axial piston pumps is of significance for enhancing the reliability and security of hydraulic systems. Most of the faults occurring in the mechanical components of piston pumps are exhibited as fault-excited impulses. However, the strong impact-induced natural periodic impulses under the common working conditions (i.e. reciprocating motion of pistons) inevitably cause interference that considerably affects the fault detection performance. In this study, a simulation-determined band pass filter is employed to improve the performance of minimum entropy deconvolution (MED) for the fault diagnosis of axial piston pump bearings. First, a finite element method (FEM) simulation is performed to determine the possible carrier frequency. Second, the carrier frequency is used as the center frequency in association with a fixed bandwidth to determine the band pass filter parameters. Finally, the MED technique is applied to enhance weak fault-excited impulses by means of kurtosis maximization. Thereafter, envelope spectrum analysis is applied to the enhanced signals to obtain faulty feature frequencies. Two case studies are conducted, using bearings with faults in the outer and inner races of an axial piston pumps under common working conditions. The case studies confirm the necessity and effectiveness of the proposed method for detecting bearings faults in axial piston pumps.