Instrumentation for high-speed digital recording of switchingsurges

Three sophisticated monitoring systems were developed and used to make unattended measurements of over 600 switching surges on 33 motors at 11 different utilities. The authors describe in detail one of the recording systems which relies on ECL (emitted coupler logic) digital electronics and high-speed commercial digitizers to measure the multiple, fast-risetime, high-voltage surges typically created by vacuum circuit breaker switching operations. This three-channel monitoring system is capable of digitizing a voltage waveform at 5 ns intervals and has 64 K bytes of memory per channel. The digitizer sampling rate is varied in real time to allow high-speed recording of up to 256 transients. Wideband capacitive voltage dividers with a flat response from below power frequencies to 20 MHz were designed to bolt directly onto the motor terminals and were used to couple the surges to the monitoring system. Results from typical field measurements made with this system on motors controlled by vacuum switchgear are also reported     

基于USB和FPGA实现的高速光子符合仪

本文基于USB2．0高速接口、大规模可编程器件FPGA及高速ECL逻辑电路,实现了一种高速多通道的光子符合设备。此设备能够同时统计八通道单光子检测器的所有可能的255种符合事件,且平均处理速度可达到每秒12．5M事件。在此速度下,可实现事件的间隔在13ns时不丢失的记录下来。同时,可利用高速USB接口,把采集到的原始通道数据直接送往主机进行存储、处理或实时监测统计结果。也可以利用FPGA先做预处理,然后再将预处理后的事件数据送往主机进行处理、分析或存储。     

多馈入HVDC的模糊自适应协调阻尼控制器设计

提出一种基于广域测量系统的多馈入高压直流（HVDC）模糊自适应协调阻尼控制器。该控制器在传统的单输入单输出控制结构基础上增加了一个模糊逻辑单元,自适应地在线调整系统的移相角。同时,增益K与模糊逻辑单元联调,以保证移相环节参数改变后整个控制通道的增益保持不变。利用Prony辨识算法和极点配置法对该阻尼控制器的固定参数进行了整定,并对整定后的参数进行了协调优化。以中国南方电网2007年网络结构为对象,给出了该模糊自适应协调阻尼控制器的设计过程及仿真结果。结果表明：该阻尼控制器能快速、有效地阻尼区域间振荡,提高交流联络线的传输能力,对不同的网络结构具有鲁棒性,可明显改善多馈入HVDc系统的稳定性。     

Programmable logic controllers

Programmable logic controllers (PLCs) are at the forefront of manufacturing automation. Many factories use programmable logic controllers to cut production costs and/or increase quality. PLCs and their unique language, ladder logic, are the workhorses of factory automation. Higher-level languages, such as sequential function charts and function blocks, ease the programming task for large systems. However, ladder logic remains the dominant language at present     

Tuning range extension by active mode-locking of external cavity laser including a linearly chirped fiber Bragg grating

We demonstrate electrical wavelength tuning by mode locking of an external cavity laser (ECL) with linearly chirped fiber Bragg grating (LCFBG). The configuration consists of a laser chip providing the gain coupled to an LCFBG with a large chip rate of 10 or 55 nm/cm providing the counter-reaction for laser oscillation. The laser chirp is electrically modulated by a sinusoidal signal in such a way that the ECL is mode locked. By changing the modulation frequency, a wavelength tuning range of 27 nm is achieved with the 10 nm/cm LCFBG, and a partial tuning range over 41 nm is demonstrated with the 55-nm/cm LCFBG. The output pulse stream at a specific mode-locking frequency and a corresponding wavelength is obtained for both positively and negatively chirped grating. A time bandwidth product reduction is measured in the case of negatively chirp grating when compared with positively chirp grating. A simple general law between the laser parameters is given (locking frequency, tuning range, and FBG chirp value). The parameters for a 40-nm tunable source modulated at 10 GHz are given. This simple tuning mechanism is very well adapted for a structure that requires accurate wavelength monitoring.     

Design and Application of Static Logic Directors

A digital computer program written by Westinghouse engineers aids the design of new static logic systems for metal mills. The computer program accepts logic equations specifying the functions to be performed. The program generates circuit drawings of logic circuitry plus paper tape for controlling an automatic wiring machine. The automatic wiring machine wires the back panel receptacles for plug-in cards which contain the integrated-circuit AND/NAND logic elements. The design engineer determines functional requirements to be performed by the logic circuits. He expresses these requirements in convenient logic statement form and adds comments on circuit functioning. Logic and comment statements are keypunched for input to the computer. The computer analyzes the equations, converts the functions to AND/ NAND logic circuits and generates the punched-paper tape required by the automatic wiring machine. In addition, the computer generates the circuit diagrams showing the actual AND/NAND circuits with complete (JIC) cross references and comments on circuit functioning. During computer processing diagnostic messages are generated to aid in finding design errors. Only one type of logic board is used in the new static logic system to perform all logic functions. This reduces maintenance to mere board replacement and greatly reduces spare board inventory. Triac outputs are featured in addition to normal contact closure outputs. Traic is a static ac switch which can operate pilot-operated solenoid valves, contactors, indicating lights, and other common ac loads. The logic system combines the advantages of fully wired integrated-circuit logic with the convenience and accuracy of computer aided design.     

换流站站用电备自投装置设计及整定

为了保证直流输电工程换流站站用电设备安全稳定运行,必须合理设计站用电系统及备用电源自动投入装置的动作逻辑。以糯扎渡直流输电工程普洱换流站为例,根据主接线形式、运行要求和具体运行工况,对10 k V备自投的五种运行工况分别设计了备自投充放电逻辑和十三种动作投切逻辑,对400 V备自投单母分段运行方式设计了两种动作投切逻辑。同时,对备自投装置的定值整定原则及定值配合相关问题进行了研究,给出了推荐定值。所提出的备自投方案经现场实际运行证明:通过10 k V和400 V两级备自投装置的配合,在各种运行工况下某路或某两路站用电源失电时备自投装置都能快速动作投切至备用电源,无需降低直流输送功率或停运,大大提高了直流系统的可靠性。     

西门子1 000 MW汽轮机DEH控制逻辑优化

为提高上汽-西门子1 000 MW超超临界汽轮机控制系统的可靠性,分析和总结数字式电液控制（DEH）系统在机组运行期间出现的故障,在不改变原有逻辑的设计思想和保护原理的基础上,优化了跳闸电磁阀控制逻辑、阀门快关保护逻辑、主蒸汽压力切换逻辑、长甩负荷逻辑、短甩负荷逻辑、汽轮机转速控制逻辑,旁路开启后的切换逻辑,消除了“跳闸电磁阀断线引起高压抗燃油（EH）油压低跳闸、电网负荷波动引起的（长）甩负荷动作”等隐患,提高机组的安全性,而且优化后的跳闸电磁阀控制逻辑、长甩负荷逻辑等在后续的1 000 MW机组中得到应用,给国内同种类型的机组提供了参考和借鉴.     

Top-down design process for gate-level combinational logic design

A pedagogical process for designing gate-level combinational logic circuits is described. The process can be used for either combinational logic circuits or the combinational logic sections of sequential logic circuits. Positive logic signals (active high signals) as well as negative logic signals (active low signals) can be used in the design process. The top-down design process allows the student to draw functional logic diagrams in a rather routine manner using the positive logic convention, or the direct polarity convention. After obtaining functional logic diagrams, realizable logic diagrams can be easily obtained using any of the common off-the-shelf gate types including AND, OR, NAND, and NOR elements with appropriate inverter symbols. The advantage of the top-down design process is that students can very easily understand and implement gate-level combinational logic functions. Examples are provided to illustrate the top-down design process in teaching combinational logic design     

Tcl/Tk语言FPGA逻辑IP库实现方法研究

针对FPGA工程应用中逻辑文件版本繁多且不易管理的问题,设计并实现了一种FPGA逻辑文件IP库,将标准的通用和专用FPGA逻辑文件进行分类管理。采用Tcl/Tk脚本语言实现人机交互界面的编写,在逻辑文件使用时进行参数配置和逻辑文件的生成,避免了人为改动逻辑代码而产生的错误,降低了代码重用过程中出错的概率,对FPGA逻辑文件管理和代码标准化有重要意义。编写的人机交互界面使用简单,灵活性强,在FPGA工程开发中具有较大的实际应用价值。     

500kV变电站备用电源自动投入装置标准设计方案的应用

对备用电源自动投入(以下简称备自投)装置标准设计原则及功能分类进行分析后,首次提出了适用于常规500 kV变电站的220kV侧母联(分段)断路器备自投标准设计方案,并对标准设计方案的充电逻辑、启动逻辑、动作逻辑、放电闭锁逻辑、定值及压板设计等进行了介绍.该设计方案操作性强,可靠性高,便于不同部门、不同单位之间的统一管理...     

安全稳定控制系统在应用中相关问题的探讨

本文介绍了广东电网的安全稳定控制系统的功能结构和控制原则;探讨了安全稳定系统的通信通道问题;针对常规备自投装置不能与安稳系统配合问题,对备自投进行技术改造,在常规的备自投装置动作逻辑基础上增加了电压不平衡逻辑、重合闸起动逻辑、开关跳位起动逻辑和低频低压闭锁逻辑;并结合实际情况,提出在安稳装置的运行维护中应注意的问题。     

Multiple-valued logic

The ultimate usefulness of a number system depends on its implementation. Multiple-valued logic has been implemented in charge-coupled devices (CCD). In this technology, logic values are encoded as charge. For example, prototype four-valued logic devices have been implemented at the University of Twente (Enschede, Holland). Hitachi has implemented a 16-valued memory that stores the equivalent of 10⁶ bits. CCD is more compact than any other VLSI technology. Although it is slower than CMOS (complementary metal oxide semiconductor), it is much faster than the disk and has the potential of replacing the disk. The use of multiple-valued logic in CCD increases its storage capacity significantly. Multiple-valued logic has also been implemented in current-mode CMOS     

核电站数字化控制系统驱动逻辑设计优化

传统面向继电器硬接线的驱动级控制逻辑设计方法已无法满足当前核电站数字化控制的需求。针对核电站数字化控制系统的特征，研究控制逻辑优化设计的技术路线及优化流程。并以全开全关电动门驱动控制逻辑为例，阐述了核电站控制逻辑优化设计的过程及优化要点，并将此优化设计方法应用到岭澳二期工程及其他核电站常规岛及BOP控制逻辑设计中，形成驱动级标准模件化，取消部分继电器，简化了逻辑电路，减少差错率，保证了参数的准确性，进而提高机组的安全和可靠性，带来较高的经济效益。     

On the use of fuzzy logic in control systems for technological equipment

The possibilities and prospects of using fuzzy logic in control systems for electro-technological equipment are analyzed based on a comparative study of standard temperature controllers of resistance furnaces and fuzzy logic controllers. It is shown that it is effective to use fuzzy logic control systems for different kinds of technological equipment. The development of fuzzy logic control systems and characteristics of their application are analyzed. The basic structures of systems constructed using fuzzy logic control are considered, is the way in which they are classified. The simulation models of temperature controllers for resistance furnaces are studied using the Matlab/Simulink software including the Fuzzy Logic Toolbox application. It is shown that a use of fuzzy controllers for simple deterministic control systems like temperature controllers of resistance furnaces does not lead to any substantial improvement in accuracy and control quality, but needs a sophisticated algorithm for control and response speed of the control system. It is assumed that a use of fuzzy logic controllers to control more sophisticated equipment characterized by the multifactor processes with a high degree of uncertainty and difficulties in determination of output parameters will allow one to obtain better results than do conventional systems.     

直流保护冗余配置的"三取二"逻辑实现方法比较

目前直流输电工程的直流保护冗余配置一般采用"三取二"方式,但在工程实际中有不同实现方法。论述了"三取二"逻辑的原理特点及其优越性,并从逻辑功能以及实现策略的角度,介绍其在几个直流输电工程中的具体应用。针对直流工程中控制保护逻辑提出了改进建议,可供未来的直流输电工程建设参考。     

Sensorless vector control of a Permanent magnet synchronuous motor with fuzzy logic observer

In this paper, a new method for sensorless vector control of a permanent magnet synchronous motor (PMSM) using a fuzzy logic observer is developed. This method is based on determination of rotor position and thereby speeds by estimating back-emf components which result from fuzzy logic observers. The rotor position angle and rotating speed are estimated by evaluating the instantaneous values of stator voltages and currents. The estimators are two fuzzy logic observers. They have two inputs: the estimated stator currents and the difference between the measured and estimated stator currents. In addition, the outputs of the fuzzy logic observers are the back-emf components in an – reference frame. The proposed method was implemented using a MATLAB/Simulink software package program. The obtained results are within acceptable error limits for a wide speed range, from 40 rad/s up to 500 rad/s.     

Solving logic equation via matrix expression

A new matrix product, called semi-tensor product of matrices, is introduced. Using this, an algebraic expression of logic is proposed, where a logical variability is expressed as a vector, a logic function is expressed as a matrix and the function values are obtained by the product of matrix with its arguments’ vectors. Under this framework, the problem of solving logic equations is investigated. For a static logic equation, we convert it into a set of linear algebraic equations. Then the solution becomes obvious. Some examples are presented to show that it is useful for logic infection.     

瞬时测频新技术研究

本文提出了两种瞬时测频技术的研究应用,数字计数瞬时测频和注入锁相测频技术。数字计数测频技术利用高速ECL电路,实现对高速脉冲进行直接测频。注入锁相测频技术利用注入锁相振荡器将注入信号的频率信息转换成相位信息,通过对相位量的测量实现对输入信号频率的瞬时测频。     

Power·delay product in COSMOS logic circuits

In this simulation work, we use COSMOS logic devices—a novel single gate CMOS architecture recently announced [1]—in multi-input logic gates, assessing its performance in terms of power·delay product. We consider three different multi-input logic circuits: a two-input NOR gate, a three-input NOR gate, and a three-input composite NOR/NAND (NORAND) gate. For this power·delay analysis, the transient TCAD simulations are employed in a mixed-mode approach where circuit and device simulations are coupled together, culminating in the delay response of the circuits as well as the static/dynamic current components. The analysis shows that all circuits, except the 3-input NOR gate, has acceptable characteristics at low-power applications and static leakage limits all COSMOS circuits at high-bias conditions.