FPSO: lessons learned

This article describes about the design of various electrical systems and installation issues of typical FPSOs (Floating, Production, Storage, and Offloading) system and provide some lessons learned. FPSO consists of a vessel or hull and a topsides facility creates many electrical interface issues between the two major parts of the completed vessel. These vessels typically have more extensive electrical systems than the typical fixed platforms. Electrical operating loads may total 40-50 MW or more depending on the vessel configuration. For the purpose of this typical FPSO design, it is assumed that the selected drivers are all electric motors. It is assumed that the total connected load is 70 MW with an operating load of 40 MW. Based on the electrical load requirements, the FPSO has an extensive electrical distribution system. The distribution system for a FPSO are very similar to those of any large distribution system. Lessons learned can only be effective if the are collected on current projects, reviewed for accuracy and sufficient detail to describe the issue, distributed to future project personnel, and incorporated into the new project design. Many of the lessons learned presented in this article are applicable to other types of electrical work and not limited to FPSOs.     

Source current harmonic analysis of adjustable speed drives under input voltage unbalance and sag conditions

Adjustable Speed Drives (ASDs) have become the primary choice for most new and retrofit precision motor-control applications, offering major improvements in system efficiency. The significant increase in the use of ASDs makes it important to understand the compatibility issues between ASDs and their electrical environment in order to appropriately design the electrical systems. Even though there have been numerous studies addressing ASD effects on power systems, models for predicting the effect of the source voltage sags or unbalance have been limited. This paper is devoted to the analysis of utility-side input current harmonics under input voltage unbalance and sag conditions and the effects of these harmonics on the distribution transformer K-factor for practical ASD systems. The relationships between the unbalanced input voltages, the resulting input current harmonics, the input inductance, and the required transformer K-factor are explored for 5 hp, 100 hp, and 600 hp power distribution systems with ASDs. The results can be used as a design guide for power distribution system design with ASDs. Theoretical derivations are accompanied by both simulations and experimental results to provide verification of key conclusions.     

Corrosion and Grounding Systems

Corrosion that occurs in the presence of dissimilar metals in the same electrolyte, or same metal in different electrolytes, or in different concentrations of the same electrolyte, has caused numerous problems in operating electric systems. This corrosion is the result of a potential difference existing between two surfaces which forces an electric current to flow. This effect is often ignored or overlooked in electrical grounding design, with the premise that electrical system protection will be hampered by the incorporation of corrosion protection. By careful design, however, both sets of requirements can be met. Some of the principles that determine corrosion and how these conditions exist in underground systems of cement plants are reviewed. The principles of grounding design are analyzed and suggestions to improve the design to minimize corrosion are discussed.     

DALI照明控制系统的研究与开发

该文在简单叙述DALI规范的基础上,给出了基于DALI标准的照明控制系统的实现,详细讨论了系统主控器端和镇流器端DALI电平和CMOS电平之间的转换电路的设计,简单叙述了DALI主控器和DALI镇流器的功能结构。实验结果表明该文设计的DALI通信系统的各项性能符合DALI规范。该文讨论的DALI照明控制系统在满足高性能的照明需求的同时,对降低照明系统的能源消耗也起到了显著的作用。该文给出的DALI通信系统同样适用于HID以及LED等新型电光源。     

蓄电池电驱动系统的匹配和优化

电驱动系统是电动自行车的关键，而蓄电池是电驱动系统的关键部件。指出，电驱动系统各部件之间的匹配和优化对于提高电动自行车的质量有着重要作用和意义。着重介绍了蓄电池和充电器之间的匹配和优化以及蓄电池放电深度与循环寿命之间的关系。     

人工神经网络在电机设计专家系统中的应用研究

首次将人工神经网络应用于电机设计专家系统。根据电机设计的特点,提出了用基于神经网络的类比法确定电机的主要尺寸。同时采用了带有可调参数的多层神经网络,并对ＢＰ学习算法进行了改进。实验表明,该方法是成功的。     

Modeling Effects of Voltage Unbalances in Industrial Distribution Systems With Adjustable-Speed Drives

AC adjustable-speed drives (ASDs) have become the primary choice for most new and retrofit precision motor-control applications with increased system efficiencies and reduced system losses. The significant increase in the use of ASDs brings the need for understanding compatibility issues between them and their electrical environment in order to design the electrical systems appropriately. Even though there have been numerous studies on ASD effects on power systems, models for predicting the effect of the source voltage sags or unbalance have been limited. This paper is devoted to analyze the characteristics of power quality indices such as input power factor, input current crest factor (CF), and the distribution transformer $K$-factor for practical ASD systems under input voltage unbalance and sag conditions. The relationships between the unbalanced input voltages and input currents, the input inductance and the input current unbalance, the input inductance and the input power factor, CF, and transformer $K$-factor are explored for 5-, 100-, and 600-hp power distribution systems with ASDs. The results can be used as a design guide for power distribution system design with ASDs. Theoretical derivations and simulation and experimental results are presented in this paper.      

A relational database approach to design of power plant and largeindustrial electrical facilities

An approach is described that utilizes a relational database for data storage, accessible directly for computational purposes during different stages of plant design, and for maintenance and expansion purposes as the future requires. Examples that use the database for design and verification are included. The authors describe how error-prone manual steps can be eliminated by handling data automatically for calculations, extracting from the database those values which were the results of prior calculations. Particular emphasis is placed on the electrical computer analysis package (ECAP) used for the design specification and analysis of electrical power systems     

Particulate Emission Control from Pulp Mill Recovery Boilers with Electrostatic Precipitators

The theory of electrostatic precipitators as it applies to the collection of particulate from a pulp mill recovery boiler is reviewed. Emphasis is placed on the fundamental physical relationships that exist between the electrical and aerodynamic characteristics of the particulate. A discussion of the difference in the behavior of the precipitator with the conventional and low odor systems is included. A comparison of the design and measured mass efficiency from a number of installations in included.     

超高速数据采集系统的优化设计

超高速数据采集系统是一种在电子、电力行业十分有用的设备，目前价格较高，如何优化它的性能价格比，是电子系统设计者普遍兴趣的问题。本文在理论分析的基础上，提出了一种超高速数据采集系统的设计思想，并具有介绍设计中的关键步骤。     

Considerations of Ground Fault Protection as Influenced by the Occupational Safety and Health Act and the Mining Enforcement and Safety Administration

The first step in recognizing the necessity of low voltage ground fault protection was taken by the 1971 National Electrical Code (NEC), Section 230-95. With the passage of the Occupational Safety and Health Act (OSHA) of 1970, more emphasis has been placed on adherence to the code. Since the establishment of OSHA, questions have been raised as to the jurisdiction between the Occupational Safety and Health Administration and the Mining Enforcement and Safety Administration (MESA). This has resulted in both agencies considering and deciding on design standards for cement plant electrical systems. Indications are that in the future, MESA standards will also recognize the necessity of adequate ground fault protection. Since the introduction of ground fault protection in the codes, there have been arguments for and against the methods of applying ground fault protection. It is for this reason that the present code requirements are minimal. In order to provide the electrical service reliability required by modern cement plants, more extensive protection is required. The intent of this paper is to evaluate the new requirements of ground fault protection. It also examines how we, as engineers concerned with electrical power systems in cement plants, approach the problems of providing safe reliable electrical systems which meet applicable code requirements and which also function satisfactorily in relation to plant operation.     

上海外高桥第三发电厂2×1000MW机组工程电气设计特点

上海外高桥第三发电厂2×1 000 MW机组工程的电气系统采用了创新优化设计,部分设计方案在国内1 000 MW机组工程建设中为首次采用。文章从电气主接线、主厂房A排外电气设施布置、主要设备和导体选择、厂用电系统、控制和保护、电缆单芯选取优化六个方面对工程电气系统设计进行了论述,较全面地展示了其电气设计特点。电厂运行实践证明电气优化设计是成功的,值得推广借鉴。     

Equivalent-circuit model for electrostatic micro-torsion mirror

Equivalent circuit model for micro-torsion mirror using open-source circuit simulator is reported, which gives a convenient technique for the design of circuits with electrostatic actuators. In the simulation, linear equations for electrical system, mechanical system, and transducer between both systems are considered. Mathematical operations of these equations are interrupted as appropriate circuits, so that a seamless multi-physics mixed simulation becomes possible.     

Reliability and statistical lifetime- prognosis of motor winding insulation in low-voltage power drive systems

Today, more and more complex power drive system (PDS) applications are being used in which an arbitrary number of inverters with different, autonomous drive frequencies are connected to a single dc bus. If long feeder cables, different inverter output circuits, and unfavorable grounding conditions simultaneously occur, then electrical oscillations with high peak values of the voltage between the motor terminals and ground may be generated. Occasionally, these can exceed the peak values of the generally better known mechanism of traveling waves [1], [2]. The complex design of recent drive systems requires more knowledge about the interaction of the components being used in the system and of the resulting effects. This knowledge forms the basis for the design of reliable drive systems. One of the major reliability topics for variable-speed power drive systems has long been the lifetime of the winding insulation system. The winding insulation system may manifest partial discharge (PD) because the electrical stress is higher for these systems than it is for drive systems that are directly connected to the line supply [1]?[4]. In the classic approach (see Figure 1) [4], [5], it is assumed that the peak voltages stressing the insulation system of the motor winding would be more or less constant and the PD inception voltage of the winding insulation would also be a deterministic value. From this, it is derived that an adequate lifetime can only be achieved by ensuring operation without PD. In case of operation with PD, the lifetime would be reduced to an unacceptable level. The approach presented in this paper considers both the generation of peak voltages, which stress the winding insulation system, as well as the associated stochastic PD inception behavior. This results in a statistically-based insulation coordination and a reliability-based economic design of the complete drive system (see Figure 2).     

Introductory probabilistic and stochastic analysis and design ofcircuits

The authors introduce the subject of probabilistic and stochastic analysis and design of circuits to nonspecialists and emphasize the need for teaching the subject to senior level undergraduates. It is argued that as this subject area synthesizes ideas from systems theory, electrical circuit analysis and design, matrix methods, probability and stochastic theories, numerical methods, optimization and symbolic algebra, this will be an ideal course to demonstrate the use of most of the background subjects, and relevant computing techniques and software. Problems solved could include electrical engineering problems, and other engineering problems modeled with electrical analogs     

聚合物高压直流电缆系统的界面处理（英文）

The developments in power transmission via HVDC networks are fast,especially in Western Europe and China.The challenges that we are confronted with are huge and considerable research and development efforts are required.Special attention is needed for high voltage direct current(HVDC)and ultra-high voltage dc(UHVDC)underground cables.For the highest voltage levels,we are still dependent upon classic technology based on mass-impregnated paper used in line commutated converter(LCC)systems.Gradually,more and more polymeric type cables are appearing on the market,as yet mainly for voltage source converter(VSC)systems.For financial,environmental and technical reasons the full focus is now on polymeric type cables,for use in LCC or VSC systems.In this paper,a closer look is taken at the interfaces in polymeric cable systems,i.e.in the cables and in the cable accessories.In the design process,we are challenged by the presence of interfaces from an electrical and thermal point of view.In the field of electrical insulation,the interfaces between different materials are generally considered the weakest parts of the equipment and under DC stresses the situation becomes even more complex due to the charge dynamics at the interface.Indeed,the design of(U)HVDC accessories has become a challenge if not a problem.This paper focuses on some of the important electrical and thermal aspects of interfaces in HVDC polymeric cables.It is discussed where we lack knowledge and where we may benefit from other scientific fields     

IGCT电磁暂态模型及损耗估算

在大功率电力电子装置的可靠性设计中,开关损耗的准确估算发挥着越来越重要的作用.结合上海50 MVA静止同步补偿器(STATCOM)试运行试验中出现的上下管发热不均衡的问题,剖析了H桥电路换流过程中各器件间的电气关系,提出了集成门板换向晶闸管(IGCT)电磁暂态模型及开关损耗计算方法.在此基础上,分析了发热不均衡的原因,并提出了改进的脉宽调制(PWM)方案.实验和仿真结果表明,该IGCT模型与实际波形接近,损耗估算方法准确,新PWM方案达到了均衡上下管发热的目的.     

基于LABVIEW和STEP7的典型惯性模拟负载控制系统的设计和实现

基于LABVIEW和STEP7软件,设计并实现了用于模拟飞机典型惯性模拟负载控制系统。该统具有优异的电功率输出和调节能力,良好的人机交互功能和保护功能,能较好的满足民用飞机电气系统的试验需求。基于LABVIEW和STEP7的直流调速系统的成功实现,不仅保障了民用飞机电气系统设计验证工作,而且还积累了民用飞机电气系统试验配套设施研制经验,对民用飞机电气系统试验具有重要的指导意义。     

multidisciplinary machine building

In today's world it is rare to find electromechanical devices without some kind of embedded intelligence. From production systems, remote control vehicles and automotive subsystems, like ABS, to everyday equipment like digital cameras, CD players and washing machines, most electromechanical devices rely on embedded controllers. Mechatronics is a system-level approach to the process of designing intelligent, embedded systems - devices that are not just electrical or mechanical, and are more than just control systems. It is a complete integration of electrical, mechanical and control system design process.     

推广风电场电气系统典型设计促进电源电网协调发展

推广风电场电气系统典型设计,采用模块化的设计手段可提升标准化建设水平,提高设计质量。对风电场电气系统风机升压变,集电线路,升压站,风电送出一、二次系统进行典型设计,规划了2 个风机升压变方案、18 个集电线路模块、15个升压变电站方案、6 个风电送出方案,旨在促进风电场建设与电网运行的协调发展。