OSI-OpenAGC及其改进

对OSI公司的自动发电控制软件作了简介 ,并对其令用户不满意之处提出了改进办法 ,如增加了机组的自动投入功能、实现了数据库维护的一致性、提供了非unix操作系统用户了解AGC软件运行情况的窗口。     

京津唐电网AGC软件包的改进研究

文章分析了美国ＥＳＣＡ公司的ＡＧＣ软件包存在的一些局限性和不足,重点分析了该软件包不适应水电厂一台ＰＬＣ控制多台机组的运行方式问题,并提出了改进办法。修改后的软件包已成功地应用于京津唐电网ＡＧＣ的生产运行。     

华中电网能量管理系统实时发电控制功能简介及其改进

本文详细介绍了华中电网能量管理系统(Energy Management System简称EMS)中的实时发电控制(Real-Time Generaition Control简称RTGEN)功能,同时简单介绍了网调为适应电网特点而对其自动发电控制(Automatic Generation Coltrol简称AGC)功能所做的某些改进工作和应用效果,并就进一步推进华中电网AGC工作提出了有关建议。     

自动发电控制算法的几点改进

常规的电力系统自动发电控制（AGC）软件不能完全满足实际应用的要求。文中在大量实际工程应用的基础上,提出了对常规AGC算法的几点改进,包括AGC控制周期、AGC控制策略、AGC数据库模型、AGC机组控制模式、区域控制偏差(ACE)平滑处理等方面。这些改进在多个网、省调EMS的实际应用中被证明是切实可行和有效的。     

自动发电控制及其应用

分析了在我省电网调度中采用自动发电控制（ＡＧＣ）的可行性和必要性，对ＡＧＣ的控制原理，目标和方式以及过程等作了详细阐述，提出了水，火电厂应采用的控制执行方式。     

智能控制-维护-技术管理集成系统(ICMMS)及其在电力系统中的应用(三)电力系统自动发电控制的ICMMS体系设计

根据ＩＣＭＭＳ体系的设计方法,对华中电力集团公司ＥＭＳ的自动发电控制部分进行了研究。对ＡＧＣ部分进行了基于ＩＣＭＭＳ体系的结构分解,并利用ＩＤＥＦ０图的形式表达了ＡＧＣ部分地用户需求。文中还利用智能单元参考模型对ＡＧＣ部分ＩＤＥＦ０图中各控制、维护和技术管理功能进行了描述。     

电力市场下基于改进遗传算法的AGC机组的选择

针对电力市场下参与竞标的各自动发电控制（AGC）机组的选择问题,提出了一种基于实数和二进制数混合编码、个体分段交叉变异的改进遗传算法。该算法采用实数模拟AGC机组的调节容量,无需解码,具有较高的收敛精度,同时采用二进制编码模拟AGC机组中标状态,充分利用了两种编码方式的优点;对群体中的个体采用了轮盘赌选择,并按容量段、状态段分别进行交叉、变异的遗传操作方法,较好地解决了电力市场下AGC机组选择这一0—1混合整数非线性规划问题。最后通过对某省实际电网的算例分析,验证了该算法的可行性。     

特高压电网投运后AGC系统的改进

从区域控制偏差、联络线功率控制模式等方面阐述特高压电网投运后对区域电网联络线功率控制的影响,分析河北省南部电网自动发电控制系统运行中存在的问题,提出特高压电网投运后对自动发电控制系统采取的改进措施.     

Improvements to a standard automatic generation control filteralgorithm

Tuning a standard digital implementation of a filter for automatic generation control (AGC) involves a compromise between achieving insensitivity to small random load fluctuations and ensuring a prompt, stable response to a power system disturbance. A personal computer-based AGC simulation program and nonlinear optimization logic were used to develop an area control error filter algorithm that reduces the amount of control action and improves control performance. Implementation on the Manitoba Hydro 4500 MW system indicated a substantial (about 80%) reduction in control pulses compared to the standard AGC filter design provided with the AGC/supervisory control and data acquisition (SCADA) system. Significant improvement has been observed both during periods of regulation for Manitoba Hydro alone and during periods of Joint AGC operation in which Manitoba Hydro also provides AGC regulation services for three neighboring utilities     

Improvements to a Microelectronic Design and Fabrication Course

This paper presents improvements made to a complimentary metal–oxide–semiconductor (CMOS) fabrication laboratory course to increase student learning and student impact (enrollment). The three main improvements to the course discussed include: 1) use of a two-mask MOS process that significantly reduced the time students took previously to design, fabricate, and verify the electrical properties of a metal–oxide–semiconductor field-effect transistor (MOSFET) process; 2) students' use of a semicustom integrated circuit (IC) design that significantly reduced the average design and processing time of previous years; and 3) development and implementation of a system of course prerequisites, which allowed a larger number of students to enroll in the course.     

FOB功能相关的发变组保护逻辑改造

大型火电机组快速甩负荷(Fast Cut Back,FCB)功能的实现,在故障后迅速恢复供电以及避免大面积停电后的黑启动方面具有重要意义.为了实现FCB功能,火电机组的设计理念必须有较大的突破,需要发电厂内机、炉、电,热各主要设备的协调配合.从电气专业角度,研究了现有发变组保护的保护类别、出口方式、保护联锁逻辑等.提出了为实现FCB功能对发变组保护相关逻辑进行的改造措施,给出了电气FCB信号的实现方法,改造后的发变组保护完全满足机组FCB功能对电气二次设备的要求.这些措施对同类型机组实现FCB功能有一定的借鉴作用.     

Improvements to an algorithm for frequency control of asynchronous motors

Two algorithms for frequency control of asynchronous motor drives—one with a constant rate of acceleration and another with stabilization of linear currents—are investigated by computer simulation. Preference is given to the latter algorithm, which ensures a highly dynamic drive in combination with protection against electrical and mechanical overload. The reliability of the computer model is verified by experimental investigation of one of the algorithms.     

12kV气体绝缘开关设备的应用简析及缺陷改进

本文分析了12kV气体绝缘开关设备的推广和应用情况,介绍了产品选择方式和应用效果,并指出了其使用缺陷,提出了改进和展望的意见。     

高频通道干扰的应对策略和改进措施

针对高频通道干扰的来源,介绍了目前高频通道干扰的应对策略和具体措施,分析了一起多台收发信机损坏事件的现象、原因、处理方法。从收发信机的设计、通道的设计和现场施工的角度提出了应对高频通道干扰的改进措施,阐明了目前收发信机通道入口处安装保护元件的必要性和具体方法。     

Improvements in ultrasound contrast agents

This article highlights the current state of ultrasound contrast imaging, including recent improvements in ultrasound contrast agents that allow the agents to pass through pulmonary circulation and even to circulate throughout the human body. A brief history of the field is presented, and current contrast agents and their properties are discussed. Clinical applications in cardiology and potential applications in other areas are also detailed     

Improvements in spiral MR imaging

The basic principles of spiral MR image acquisition and reconstruction are summarised with the aim to explain how high quality spiral images can be obtained. The sensitivity of spiral imaging to off-resonance effects, gradient system imperfections and concomitant fields are outlined and appropriate measures for corrections are discussed in detail. Phantom experiments demonstrate the validity of the correction approaches. Furthermore, in-vivo results are shown to demonstrate the applicability of the corrections under in-vivo conditions. The spiral image quality thus obtained was found to be comparable to that obtainable with robust spin warp sequences. Presented in parts at the 15th meeting of the ESMRMB, Geneva, September, 1998.