A fuzzy-based power system reliability evaluation

This paper presents a fuzzy version for evaluating the reliability of complex power systems. In the proposed algorithm, fuzzy set theory was used to evaluate the coefficients of different terms in reliability expression. The coefficients of the reliability expression are composed of system tie/cut sets and link capacities. The proposed algorithm has made it possible to on-line power system security assessment depends on the system history and past experience. The entire logic of the algorithm is explained in detail and verified through a numerical example.     

A high-performance edge heater for the hot strip mill

A transverse magnetic flux type of induction edge heater for hot strip mills that can sufficiently heat the edge portion of a transfer bar from the very head end to the very tail end was developed. This was accomplished not only by applying the magnetic flux leakageless C-type edge heater that consists of a single magnetic circuit but also by developing an algorithm for setting the optimum air gap between the upper and lower inductors and the firing angle compensation circuit. This circuit enables the main power source thyristor inverter to be operated even when the applied load is so light that the thyristor devices of the inverter cannot commutate without the circuit. Mechanical characteristics inspections of hot strips heated by the edge heater show that the elongation characteristic of the edge parts is improved from the head to the tail end of hot strips. From this it is possible to obtain uniform distribution of the elongation characteristic all along both the width and length of hot strips. Thus, the contribution of the new edge heater to the improvement of the quality and yield rate of hot strips has been confirmed     

基于Wince嵌入式内核的新型电力参数实时测量系统

针对电力系统中电能参数测量的具体要求,设计了基于WinCE嵌入式内核的电力参数测量系统.硬件设计采用ARM+DSP主从处理器构架,高性能的双核处理器结构实现对数据的快速、精确处理,以实现电能参数实时在线测量;运行于WinCE操作系统平台上的主控软件完成电力参量数据的显示、存储和管理,提供了人机友好交互的操作界面.基于模块化的设计思想,降低了系统复杂性,便于维护和更新.该系统能够为电力调度、检修提供服务,保证电网安全与经济运行.     

一种电压闪变实时检测的新方法

提出了一种基于数学形态学均值滤波与能量算子包络检测的电压闪变实时检测的新方法。区别于其它去噪滤波算法,改进的数学形态学的滤波器只含有加减和一次除法运算,而能量算子包络检测只需要对被测波形的三个样本进行两次乘法和一次减法运算,使得所提出的算法快速、简洁。仿真结果表明,所提算法能够准确地检测出闪变波形的包络,并且克服了Teager能量算子算法对噪声和突变的敏感性,适合电压闪变的实时检测。     

一种新颖的无功功率离散化实时算法

运用三角函数变换的方法，提出了一种新颖的与计算有功功率相似的电网无功功率的离散化实时算法。用电压、电流、基波频率量快速、准确地计算出无功功率，适用于实时性要求高的无功测量仪表与无功补偿系统。定量分析了此算法存在的理论误差，讨论了电压与电流相乘时的间隔时间对误差的影响，给出了此算法的实现程序。     

一种电压闪变实时检测的新方法

提出了一种基于数学形态学均值滤波与能量算子包络检测的电压闪变实时检测的新方法.区别于其它去噪滤波算法,改进的数学形态学的滤波器只含有加减和一次除法运算,而能量算子包络检测只需要对被测波形的三个样本进行两次乘法和一次减法运算,使得所提出的算法快速、简洁.仿真结果表明,所提算法能够准确地检测出闪变波形的包络,并且克服了Teager能量算子算法对噪声和突变的敏感性,适合电压闪变的实时检测.     

Advanced automation concept of runout table strip cooling for hotstrip and plate mills

An advanced automation concept, based on operational experience with the classical concept, has been developed for the automation of cooling sections. An essential aspect is the use of the thermophysical process knowledge for setup calculation and for control during production. The cooling section is, therefore, regarded as a system through which unsteady energy flows. This system definition also allows the flexible use of the final control elements, since the temperature profile between the pyrometer of the finishing train and that of the coiler can be continuously calculated, i.e., observed during production and compared and controlled with a reference temperature profile. This has enormous advantages as the influence of process disturbances, e.g., by power speedup and speed down, is effective simultaneously at each point within the cooling section. The advanced control concept combines proven model technology with new features that provide a high degree of flexibility concerning dynamically changing process parameters and transient conditions. The advanced automation concept has already been implemented in the cooling section of two conventional hot strip mills     

Chaotic ant swarm optimization for fuzzy-based tuning of power system stabilizer

In this paper, chaotic ant swarm optimization (CASO) is utilized to tune the parameters of both single-input and dual-input power system stabilizers (PSSs). This algorithm explores the chaotic and self-organization behavior of ants in the foraging process. A novel concept, like craziness, is introduced in the CASO to achieve improved performance of the algorithm. While comparing CASO with either particle swarm optimization or genetic algorithm, it is revealed that CASO is more effective than the others in finding the optimal transient performance of a PSS and automatic voltage regulator equipped single-machine-infinite-bus system. Conventional PSS (CPSS) and the three dual-input IEEE PSSs (PSS2B, PSS3B, and PSS4B) are optimally tuned to obtain the optimal transient performances. It is revealed that the transient performance of dual-input PSS is better than single-input PSS. It is, further, explored that among dual-input PSSs, PSS3B offers superior transient performance. Takagi Sugeno fuzzy logic (SFL) based approach is adopted for on-line, off-nominal operating conditions. On real time measurements of system operating conditions, SFL adaptively and very fast yields on-line, off-nominal optimal stabilizer variables.     

自动位置控制在热轧带钢卷取区的应用

侧导板、夹送辊、卷筒的位置控制对整个卷取区至关重要,直接影响卷取成功与否。详细阐述侧导板、夹送辊、卷筒的自动位置控制(APC)的思想、算法及控制工艺。     

A real-time operation analysis system for distribution networks

This paper describes the functional aspects and characteristics of a real-time operation analysis system, called interplan operation (IO), operating in the distribution operation center (COD), AES Sul Distribuidora Gaúcha de Energia, in São Leopoldo, RS, Brazil. Among the main characteristics of the system is the integration between different types of information from distinct databases, as reference files, measurements, events, maintenance crews, and operation information. With the user-friendly interface and graphic access to data basis, operation, and calculation information, interplan operation has been proven a flexible, well-built system, efficient in operation analysis for decision-making. The system is composed by several technical modulus embedded into the system, as the optimized switching module, based on a genetic algorithm of specific and innovating characteristics to solve problems. This module is the result of the research and development program carried out in AES Sul.     

非全相运行的电力系统多模块数字实时仿真模型

在电力系统规划中，设计与检验电力系统的保护、控制以及调度设备时，动态模拟装置起着重要的作用，应用多模块耦合算法，将一个典型的高阶电力系统分解为多个低阶模块，然后分别对各低阶模块进行建模，各模块之间通过其端口的电压与电流关系进行耦合，对一个典型系统的非全相运行状态建立了其相应的多模块耦合算法模型，并且在高性能的PC机系统上以较小的仿真步长实现了其相应的数字实时仿真，系统实时运行的结果表明，提出的电力系统非全相运动状态的多模块耦合算法模型能够满足实时仿真系统的要求。     

A real-time short-term load forecasting system using functionallink network

This paper presents a new functional-link network based short-term electric load forecasting system for real-time implementation. The load and weather parameters are modelled as a nonlinear ARMA process and parameters of this model are obtained using the functional approximation capabilities of an auto-enhanced functional link net. The adaptive mechanism with a nonlinear learning rule is used to train the link network on-line. The results indicate that the functional link net based load forecasting system produces robust and more accurate load forecasts in comparison to simple adaptive neural network or statistical based approaches. Testing the algorithm with load and weather data for a period of two years reveals satisfactory performance with mean absolute percentage error (MAPE) mostly less than 2% for a 24-hour ahead forecast and less than 2.5% for a 168-hour ahead forecast     

一种电力系统频率的实时估算方法

提出了一种曲线拟合结合泰勒级数展开的电力系统实时频率测量算法,采用分子、分母绝对值相加的方法来避免了计算过程中分母过零点的影响,理论分析及数字仿真表明,该算法实现简单,有很高的计算精度,对谐波也有一定的抑制能力.完全能满足电力系统实时频率估算的要求.     

一种实用的电力系统频率实时测量方法

为解决非同步定频采样系统对电力系统频率测量时存在的运算复杂、实时性不好等问题,提出了一种实用的频率实时测量方法。该方法是基于周期过零点插值原理,通过对A/D采样的离散序列进行FIR带通数字滤波,然后对相邻的同方向过零点进行插值求取频率的估计值。针对电力系统待测信号中不含谐波、含有2-16次谐波以及含有随机噪声的不同情况,分别进行了仿真验证,最后与离散傅里叶变换(DFT)测频算法的结果进行了对比。结果表明该方法抗干扰性和测量精度都要优于DFT测频算法,而且该方法计算量少、实用性强、实时性好、测量精度高,能满足电力系统频率测量要求。     

一种电力系统频率的实时估算方法

提出了一种曲线拟合结合泰勒级数展开的电力系统实时频率测量算法,采用分子、分母绝对值相加的方法来避免了计算过程中分母过零点的影响,理论分析及数字仿真表明,该算法实现简单,有很高的计算精度,对谐波也有一定的抑制能力。完全能满足电力系统实时频率估算的要求。     

新型电能质量在线监测系统在宝钢热轧厂的应用研究

1概述在宝钢热轧厂2050生产车间,大部分轧机主传动装置使用晶闸管整流的直流传动系统,小部分轧机主传动使用晶闸管变流的交—交变频传动系统,均产生严重的无功冲击和高次谐波。为此,轧机主传动负载所在的两条35 kV母线分别安装有两套SVC装置,轧机辅传动负载所在的六条6 kV母线均安装有FC滤波装置。生产一般带钢品种的轧制情况下,在两套SVC装置和FC滤波装置的补偿和谐波吸收作用下,35 kV母线的电压波动和电压畸变情况可控制在标准范围内。当生产X系列管线钢等特种带钢产品时,轧机的穿带速度很低,传动系统在电网侧的无功功率和谐波含量…     

基于多线程技术的数字保护实时仿真系统

一次系统实时数字仿真对仿真步长有着严格的要求,一般为50～60 μs.而微机保护等控制系统对仿真步长的要求则低得多,两者相差达一个数量级以上.这给在RTDS上实现保护实时、闭环数字仿真系统带来很大困难.首先介绍了RTDS中控制系统以及用户自定义组件(UDC)的数学模型,分析了实时仿真系统所遇到的问题,指出多线程技术可以解决控制系统采样间隔与仿真步长不一致的问题,从而有效缩短最小时间步长;然后详细介绍了多线程技术的原理以及在RTDS中的实现方法,并开发了基子多线程技术的保护实时数字仿真系统模型;最后以一套纵联保护实时仿真模型为例,在RTDS系统中验证了多线程技术的优越性.     

A real-time control system for single-phase unified power flow controllers

This paper proposes a real-time control system for a single-phase unified power flow controller (UPFC) which is constructed as a pilot power-quality compensation equipment of an electrical railway, and shows simulation and experimental results. For simulation, the control system is modeled in the form of block diagrams by using the Simulink, where the main control effort is focused on the power flow control with the UPFC and the hysteresis current controller is adopted to control the single-phase inverters of the UPFC. And for a small-scale rapid prototyping of the UPFC-equipped control system, the simulation blocks are modified and a real-time control platform is developed by using the real-time workshop and multiple digital signal processors. Both simulation and experiment results have proved the effectiveness of the proposed control system.     

钻井事故实时咨询系统

钻井事故实时咨询系统是在分析下传事故诊断结果的基础上,借助数据库查询原理,向用户实时提供钻井事故的预防、控制及处理的自动化查询系统。