正压浓相气力输灰系统常见故障及处理方法

简要介绍了正压浓相气力输灰系统及其工作原理，分析了在运行过程中经常发生故障的原因，并提出预防措施及处理方法     

PLC在电除尘气力输灰的应用

本论文主要是针对PLC在山东华聚能源有限责任公司东滩矿电厂75t/h中压煤泥流化床锅炉电除尘气力输灰上的成功运用,实现电厂烟气达标排放,保护了电厂所在地的环境,为电厂带来一定的社会效益和经济效益。     

气力输灰系统设计、选型和运行的建议

文章探讨火电厂气力输灰系统在设计、选型和运行维护中存在的一些问题,并提出相关避免及解决问题的建议。     

气力输灰系统运行中存在的问题及对策

在生产实践的基础上,对气力输灰系统运行中存在的常见问题进行了论述,重点分析了输送设备上部和灰库卸灰设备的漏灰问题,以及输灰管道、仓泵设备和阀门的磨损问题、并提出了相应的对策。     

火电机组省煤器灰输送中存在的问题及对策

火电机组省煤器单元输灰系统运行成本高、易堵管、输灰管道磨损严重等问题。分析了产生的原因,提出了优化方案,并通过对比优化前后的输灰系统的使用情况,结果表明,优化后的正压浓相气力输灰系统是一种能有效降低运行成本、减少系统维护量的方法。     

Ferranti and Merz: power transmission system design engineers

Ferranti and Merz were the architects of power transmission system design in Britain. Ferranti's design concept broke through the parochial model of electricity supply inherent in the Electricity Lighting Acts of 1882 and 1888. Although the concept of a remote high-power central station with high-voltage transmission and large-area distribution was not realised by Ferranti in 1889, it was realised by the power companies. Merz was foremost in using the Ferranti design concept in 1901 for the Newcastle, later the North East, Electric Supply Company (NESCo.). Later Merz introduced a new radical concept by the interconnection of a number of power stations. He did this first for NESCo. And in 1916 he proposed this as a model to be adopted for British electrification. Merz was unique in first solving the technical problems of power station interconnection and then realising that such a transmission system best suited an electricity supply for the industrial areas of Britain     

Non-sinusoidal power theory in a power system having transmission lines with frequency-dependent resistances

Recently power systems suffer from harmonic pollution, and the resistances of transmission lines are frequency-dependent due to eddy currents and the skin effect. This frequency dependency should be taken into account, so that apparent power and the power factor accurately reflect transmission loss under non-sinusoidal conditions. A generalised power theory that is applicable to a power system whose transmission/distribution lines have frequency-dependent resistances, and where a unity power factor is given as the minimum loss condition is proposed     

Power system damping from real and reactive power modulations of voltage-source-converter station

As gas turbines, wind farms, run-of-river hydro, photovoltaic and other renewable energy sources are becoming a growing component in the power system, the feasibility of applying the controllability of their expensive frequency-changers [based on voltage-source converters or (VSCs)] is examined to provide system damping. It is shown that irrespective of the location of the VSC-frequency changers along the transmission line, significant damping is available by the combined control of real and reactive power modulations. The finding is reached by eigenvalue analysis of the linearised equations and confirmed by digital simulation (PSCAD/EMTDC). Digital simulation is also applied to evaluate the size of injected complex power required for the best damping for a given converter rating.     

Modelling of electronic power transformer and its application to power system

Mathematical models of an electronic power transformer (EPT) are established for steady-state and transient stability investigations. To simplify oscillation damping analysis, a simplified dynamic model is developed by neglecting transients of a high-frequency transformer and filter inductors. Comparison between the simplified dynamic model and the detailed model is carried out by simulations using numerical computation and Matlab/Simulink to verify the accuracy of the developed model. For the purpose of the EPT controller design, a small-signal model of the EPT in a d-q synchronous rotating reference frame is established by linearisation about the operating point. According to the developed models, linearised Phillips-Heffron models of the power systems installed with the EPT are presented. Afterwards, as a case study, based upon the Phillips-Heffron models, the damping function of EPT is discussed and its performance is verified by numerical simulation.     

高压输电塔-线体系振动台模型非等比例问题研究

高压输电塔-线体系模型进行振动台试验时,由于模型跨度大以及实验室尺寸等条件限制,输电塔-线体系中塔与线的比例因子很难保持相同,此时需要将导（地）线的比例进行修正。从数值分析的角度出发,以辽宁盖州500kV输电线路的一段输电塔-线体系为例,输电塔的比例保持不变,导（地）线的修正系数分别取为1.0、0.5和0.4的情况下进行纵向和侧向下的一致和多点地震响应时程分析。研究结果表明,导（地）线的比例进行修正后,输电塔-线体系的地震响应与原模型保持一致,因此这种修正模型的振动台试验的精度满足工程要求。     

Application of support vector machines for fault diagnosis in power transmission system

Post-fault studies of recent major power failures around the world reveal that mal- operation and/or improper co-ordination of protection system were responsible to some extent. When a major power disturbance occurs, protection and control action are required to stop the power system degradation, restore the system to a normal state and minimise the impact of the disturbance. However, this has indicated the need for improving protection co-ordination by additional post-fault and corrective studies using intelligent/knowledge-based systems. A process to obtain knowledge-base using support vector machines (SVMs) is presented for ready post-fault diagnosis purpose. SVMs are used as Intelligence tool to identify the faulted line that is emanating and finding the distance from the substation. Also, SVMs are compared with radial basis function neural networks in datasets corresponding to different fault on transmission system. Classification and regression accuracies are is reported for both strategies. The approach is particularly important for post-fault diagnosis of any mal-operation of relays following a disturbance in the neighbouring line connected to the same substation. This may help to improve the fault monitoring/diagnosis process, thus assuring secure operation of the power systems. To validate the proposed approach, results on IEEE 39-Bus New England system are presented for illustration purpose.     

火电厂联通疏水管失效分析

本文采用金相显微镜和电子显微镜研究了联通水管失效的原因,这对改进产品质量有很大意义。     

板式基础上非线性隔振系统的功率流传递特性

针对工程实际中柔性基础的隔振问题,建立了机器一非线性隔振器-柔性基础组成的隔振系统理论模型,其中,用四边简支矩形薄板模拟弹性安装基础.运用谐波平衡法和Newton迭代法对系统在简谐激励下的动态响应进行了近似求解,并通过计算分析了主谐波分量对于基础的振动功率流输入,讨论了隔振器的非线性阻尼和刚度特性对系统隔振效果的影响.研究表明,在低频段,较小的阻尼非线性特征参数和较大的刚度非线性特征参数利于隔振;在高频段,较大的非线性特征参数具有较好的隔振性能.     

核电站专用多工况分区控制空调设备的电气控制系统设计

设计一台核电站专用节能型双金属复合箱体结构的组合式恒温恒湿空调机,该机组利用新风冷却调节室内温度,能够实现多工况分区控制及风机变频控制。双金属复合结构箱体可以满足核电站防腐、耐辐照及抗震等特殊要求;多工况分区控制的应用,能够充分利用新风,改善传统空调机组冷、热抵消的弊端,实现机组节能运行。     

Sequence operation theory and its application in power system reliability evaluation

The primary objective of this paper is to report a new mathematical approach named sequence operation theory (SOT) to handle the difficulty and complexity of power system reliability evaluation (PSRE) that arises from integrated resource planning or under deregulation environment. Enlighten by traditional discrete convolution, four type of discrete sequence operation (DSO) named addition-type-convolution, subtraction-type-convolution, AND-type-product and OR-type-product, are proposed in this paper. A special type of discrete sequence named probabilistic sequence (PS) has been studied in detail. In order to put SOT into practice, the definition of expected value of PS is presented according to Probability Theory. Moreover, some physical concepts of DSO between two PSs have been discussed. As a exact mathematical theory, all the properties of SOT are proved.SOT is a new general mathematical theory and wide application in many fields could be expected. A new PSRE method based on the theory of SOT is briefly reported in this paper. When dealing with traditional PSRE problems, such as IEEE Reliability Test System, the numeric example shows that the result of our approach is almost the same as that of traditional one. However, the new method can solve the newly emerging problem of PSRE in integrated resource planning or under deregulation environment, where the whole demand would be classified into several types and each type can be given a certain reliability index.