A few remarks about assessment methods of electric power quality on ships – Present state and further development

This paper concerns the problem of reliable assessment of a power quality in naval networks. Two aspects of the problem were discussed. Firstly, the parameters for electric power quality assessment and their permissible levels were presented. Further, the methods of their measurement were analyzed. Especially the critical analysis of relevant IEC standards was presented and proposals for their amendment were laid. These considerations were based on the results of the original author’s research carried out in ship electrical power systems for a few years. Finally, the original and complete methods of signal processing and basic features of newly constructed instrumentation for power quality assessment were shown. Presented paper is a continuation and in some respect the synthesis of the earlier works prepared by the same author completed by new contribution.     

Estimator-analyzer of power quality: Part II - Hardware and research results

The paper presents the new instrumentation for power quality assessment, called the estimator-analyzer of power quality. It is consistent with the general idea of waveform parameters measurement set out in IEC Standard 61000-4-7, although it utilizes the authors’ original methods of measurement of power quality parameters. The applied methods and algorithms were described in the first part of the paper. The hardware of the device and the experimental results are presented and discussed in this paper. The device has been tested with signals of known characteristics and also in the electric power system of a ship.     

气动系统的能量消耗评价体系及能量损失分析

在分析基于空气消耗量的现有能量消耗评价体系的基础上,阐述一种新的能量消耗评价量——气动功率。气动功率定义为单位时间内流过指定截面的压缩空气所含有的有效能,而有效能是以大气温度和压力状态为外界基准,流动压缩空气具有的对外做功能力。该有效能是一个相对于大气状态基准的相对量,建立在气动系统都工作在大气环境下这样一个事实基础上。基于气动功率概念,侧重分析导致气动功率损失的因素,讨论气动系统能量损失机理及各个构成环节的损失情况,为明确节能目标奠定理论基础。     

船舶动力装置课程教学问题与改革研究

船舶动力装置是船舶的重要组成部分,船舶的性能很大程度由动力装置来保证。基于高校船舶动力装置课程教学改革中存在的问题及当前新工科对学生综合素质的要求,提出了改进教学的具体操作方法,以提高相关专业大学生专业基础理论水平,拓宽知识面,增强工程实践和解决工程问题的能力,为船舶行业的发展提供优秀人才。     

船舶余热利用sCO2布雷顿循环发电技术综述

在船舶动力系统能量转换和利用过程中,实现烟气余热的最大效率回收是降低船舶能效设计指数（EEDI）的有效途径。超临界二氧化碳（sCO2）发电系统在船舶余热循环利用方面所具有的技术优势已引起全球船舶行业的高度关注,而如何将其与船舶动力系统有机集成并实现高效、稳定联合循环运行发电,正是当前制约该新型技术实船应用的瓶颈。概述了sCO2布雷顿循环发电的基本原理、典型技术特点及循环结构,分析了国内外研究机构针对sCO2发电系统在船舶余热循环利用方面的研究现状,探讨了现阶段面向船舶主机余热发电工程化应用所存在的关键技术问题,从而为推进sCO2布雷顿循环发电技术在船舶烟气余热回收利用领域的基础理论研究和工程方案设计提供理论参考。     

Novel Ship Propulsion System

As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion (IHP), is put forward to meet the development of modem ship. Principle of IHP system is discussed. Working condition matching characteristic of IHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of IHP ship and direct propulsion (DP) ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between IHP ship and DP ship is conducted. The results show that cabin arrangement of IHP ship is very flexible, working condition matching characteristic of IHP ship is good, the ratio of power to weight of IHP ship is larger than DP ship, and maneuverability is excellent. IHP system is suitable for engineering ship, superpower ship and warship, etc.     

回收船舶柴油机余热的有机朗肯循环系统热力学性能比较分析

利用有机朗肯循环(ORC)系统对某型号船舶柴油机(最大持续功率为996 kW)的余热进行回收,以系统净输出功为指标,对比分析5种不同结构形式的ORC系统的热力学性能,结果表明:回收柴油机排烟余热的基础ORC系统最大净输出功达49.83 kW;增设回热器进一步回收膨胀机出口工质废热后,系统最大净输出功达54.84 kW;...     

A method for discriminating original pulses in online partial discharge measurement

Partial discharge (PD) measurement is a promising method for condition assessment of insulation systems in high voltage equipments. Conventional PD measuring systems have some difficulties in the measurements especially in online conditions and noisy environments. There is a growing tendency to use new measuring systems for separation of PD pulses from different sources and rejection of external noises. In this investigation a new ultra wideband PD measuring system and relevant methodology are discussed. The proposed system uses an efficient detection method for extracting PD pulses embedded in noisy signal, meanwhile, a wavelet multiresolution analysis is applied to reduce background and communication noise level. In this paper some new and modified features for pulse classification procedure have been proposed. The proposed system, methodology and features have been implemented on a hydrogenerator and also a power transformer. Finally performance of the system is discussed.     

船用混合动力推进系统能量管理系统关键技术研究现状

面对能源短缺和排放法规严格的问题,使用新型混合动力系统成为船舶未来发展的重要方向.分析了航运业所面临的挑战,阐述了船舶混合动力优势和必要性,并总结归纳能量管理系统的拓扑结构和实现构架;对能量管理系统研究现状进行剖析,提出了混合动力系统多能源耦合能量管理策略的发展路线;剖析了船舶混合动力系统能量管理策略研发所面临的挑战,...     

克令吊中液压闭式系统的优化设计

我国海上风电规模连续快速增长,新造一条风电安装工程船,周期长,成本高,因此许多潜在用户希望通过旧船改造实现海上风电安装功能。克令吊是风电安装上最主要的设备,通过对克令吊闭式液压系统的优化设计,大大缩短了旧船改造的周期,降低了旧船改造的成本,同时提高了克令吊设备的安全性和可靠性。     

船舶维修设计的原则及效能研究

在研究了国内外现状的基础上,结合国内船舶制造的实际,提出了船舶维修设计原则,进行了维修设计的效能分析.在维修设计中,应该坚持系统性和全面性、坚持全过程和全寿命、坚持决策支持和服务优先.开展维修设计研究,对加速推进船舶设计标准化、改革传统的船舶维修模式、实现全寿命维修质量管理、提高船舶维修水平和软件系统质量,具有重要和积极的意义.     

新型双向可控离合器的初步研究

联合动力装置现在已成为舰船动力的发展趋势,在这种装置中需要一种可以双向传递功率的离合器,即双向可控离合器.主要讨论了双向可控离合器在联合动力装置中的应用,根据离合器的工作特点提出两种初步方案,对两种方案的工作原理及结构特点进行了论述,并进行了比较分析,为联合动力装置中双向可控离合器的设计提供依据.     

Severity assessment issues for short voltage dips

This paper analyzes the impact of the systematic deviations that can be found in the measurements of voltage dips (also called sags) adopting algorithms in agreement with standards as it is commonly done by commercial instruments. This analysis is particularly interesting because the results of dip measurements are utilized for the calculation of severity levels and the assessment of site indexes that are parameters adopted in determination of the quality level of the power supply, but also to develop planning and design criteria for new electrical power grids or to select equipment with proper intrinsic immunity. The paper starts with an insight about dip phenomenon presenting the most important systematic deviations introduced by standard algorithms. Then, the remarkable effects on severity index calculations are presented with particular attention to short dip events. The conditions of non-detection, for dip shorter than 1 cycle, are analytically calculated and a great ambiguity for a dip even shorter than 2 cycles is shown.     

基于LabVIEW的微网电能质量监测评估系统

针对现阶段微网电能质量实时监测和综合评估系统软件缺失的问题,对微网电能质量合理的综合评估方法进行了研究,探讨了一种基于LabVIEW编程平台的电能质量监测评估系统的设计方案.首先,提出了一种基于改进的层次分析法（AHP）和灰色理论相结合的微网电能质量综合评估方法.然后,利用LabVIEW和Matlab Script语言混合编程优势,通过LabVIEW平台开发了一套可实现微网电能质量实时监测、合理评估和综合管理的智能系统,并利用学校的微网模型对该系统进行了测试.研究结果表明,该系统能实时监测微网各项电能质量指标,具有报警录波功能,同时可对微网的综合电能质量作出合理的评估,可生成报表以汇总微网各单项电能质量指标和综合电能质量评价结果,具有良好的工程化应用前景.     

A new combined method in active filter design for power quality improvement in power systems

The voltage & current harmonics produced by nonlinear loads in power systems cause a reduction in power quality. In order to improve the power quality, active power filters (APFs) can be used. In this paper, a new control system for designing active filters despite nonlinear loads of electric arc furnaces (EAFs) is presented. The system is composed of three main parts: computation of reference currents, regulation of DC capacitor voltage, and production of firing pulses. In the first part, the active filter control system is presented based on the combination of the synchronous detection method and instantaneous power theory. In the second part, the DC capacitor voltage regulator is applied, producing a reference current and a proper voltage regulator is developed. For the third part of the control system, we use a PI controller to provide some conditions that follow the reference current in a complete cycle, and generate firing pulses by the hysteresis method. The proposed control system not only reduces the voltage and current harmonics in power systems but can also improve the power quality indices. The above design was implemented in the EAF system of the Mobarakeh steel complex (Isfahan, Iran). The simulation results show the effectiveness of the APFs in improving the power quality indices.     

东风康明斯亮相2012北京国际车展

4月23日至5月2日,东风康明斯发动机有限公司携手东风商用车公司以及东风汽车股份有限公司,参展于中国国际展览中心(新馆)举行的2012北京国际汽车展览会。东风康明斯展出旗下创新性产品:ISZ13升发动机和ISDe4.5升发动机,以呼     

The running performance of externally pressurized power screws

The stationary performance of an externally pressurized power screw-nut system with the suggested new profile is shown to be more efficient than systems with traditional types of power screws working under the same conditions. Such systems are characterized by their lower requirements of lubricant volume rate of flow and power consumption and by their higher load-carrying capacity and stiffness.The optimum proportions and profile of the power screw-nut system under running conditions are presented together with the corresponding running performance. It is confirmed that the suggested power screw-nut system offers the optimum performance under all circumstances.     

Experimental determination of the propagation of wireless signals on board a cruise ship

The characterization of the wireless channel on board a cruise ship is considered by means of frequency domain measurements of received power and propagation attenuation. This electromagnetic environment is rather new and is characterized by abundance of reflecting and diffracting elements, so that a significant difference with respect to more common residential and office environments was found. The measurement setup is simple and easy to position and operate; the measurement results were validated by comparison with another independent measurement setup. The results indicate that the power losses for corridors are not a power law of distance, due to scattering; even in large environments such as restaurant halls the presence of reflecting and scattering objects and installations largely affects the received power.     

Automation of hull plates classification in ship design system using neural network method

Manufacturing the complex surface plates in stern and stem is a major factor in cost of a preliminary ship design by computing process. If these hull plate parts are effectively classified, it helps to compute the processing cost and find the way of cut-down the processing cost. This paper presents a new method to classify surface plates effectively in preliminary ship design using neural network. A neural network based ship hull plate classification programme developed and tested for the automatic classification of ship design. The input variables are regarded as Gaussian curvature distributions on the plate. Various applicable rules of network topology are applied in ship design. By observing the results of the proposed method, the effectiveness of the proposed method are discussed. As a result, high prediction rate was achieved in ship design. And the proposed method will contribute to reduce the production cost of ship.     

A study on an anti-rolling system design of a ship with the flaps

Roll stabilization systems for ships are employed to increase comfort for passengers, maintain full working capabilities for members of the crew and prevent cargo damage. In this paper, we have investigated the usefulness of active stabilizing system to reduce ship rolling under disturbances, using varied reaction of the flaps. In the proposed anti-rolling system for a ship, the flaps as the actuator are installed on the stern to reject rolling motion induced by disturbances such as wave. The action induced by flaps depends on power of disturbances and can take the ship balance. Especially, in this study we define the system parameters under the given system structure and design the controller to evaluate the usefulness of the proposed system.