Stability Enhancement of Small-Scale Power Grid with Renewable Power Sources by Variable Speed Diesel Power Plant

This paper proposes a power control method to improve a stability of a small-scale power grid with renewable energy sources. In an isolated small- scale power grid such as an island, diesel power plant is main power source which has an environmental burden and expensive running cost due to high priced fossil fuel. Thus, expanding installation of the renewable energy sources such as a wind power is strongly desirable. Such fluctuating energy sources, however, harm power quality of the small-scale power grid, and in addition, conventional power plant in the small-scale power grid cannot, in general, stabilize the grid system with such fluctuating power sources. In this study, Variable Speed Doubly-Fed Induction Generator (VS-DFIG) is proposed to be in-stalled at a diesel power plant instead of a conventional Fixed Speed Synchronous Generator (FS-SG), because quick control of a power balance in the small-scale power grid can be achieved by using the inertial energy of VS-DFIG. In addition, utilization of a Battery Energy Storage System (BESS) is also considered to assist cooperatively the VS-DFIG control. As a result of the simulation analysis by using the proposed method, it is verified that frequency fluctuations due to renewable energy source can be effectively reduced by quick power control of the VS-DFIG compared to the conventional FS-SG, and further control ability can be obtained by utilizing BESS. Moreover, the transient stability of a small-scale power grid during a grid fault can also be enhanced.

Experimental investigation of power output and soot emission for micro-emulsification diesel oil using for vehicle

The micro-emulsification diesel oil with water dopant of 5%,10% and 15% was prepared using the NAA micro-emulsification compound developed by the authors.The engine bench testing was carried out on the 485QB diesel engine.From the testing results of velocity,loading and exhaust gas,it can be seen that the power decreases and the fuel consumption increases using the micro-emulsification diesel oil.But based on the actual fuel consumption,the use of emulsification diesel with water dopant of 10% can get the effect of oil saving;while with water dopant of more than 15%,it doesn't work evidently.The investigation shows that using the micro-emulsification diesel oil,we can reduce the exhaust gas pollution and receive better environment benefit.

Performance of a Wind-Diesel Hybrid Power System with STATCOM as a Reactive Power Compensator

The paper deals with automatic reactive power control of an isolated wind-diesel hybrid power system. The power is generated by diesel engine and wind turbine as prime movers with electrical power conversion by permanent-magnet synchronous generator (PMSG) and permanent-magnet induction generator (PMIG) respectively. The mathematical model of the system developed is based on reactive power flow equations. The paper investigates the dynamic performance of the hybrid system for 1% step increase in reactive power load with 1% step increase in input wind power.

Research on H_2 speed governor for diesel engine of marine power station

The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H2 speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.

Application of Space-time Conservation Element and Solution Element Method in Intake and Exhaust Flows of High Power Density Diesel Engine

A one-dimensional pipe flow model of single-cylinder diesel engine is established to investigate the intake and exhaust flow characteristics of diesel engine in the condition of high power density(HPD).A space-lime conservation element and solution element(CE/SE)method is used to derive the discrete equations of the partial differential equation for the intake and exhaust systems.The performance parameters of diesel engine with speed of 2100 r/min are simulated.The simulated results are in accordance with the experimental data.The effect of increased power density on charging coefficient is analyzed using a validated model.The results show that the charging coefficient is slowly improved with the increase in intake pressure,and is obviously reduced with the increase in engine speed.

Effects of Hydrogen Addition on Power and Emissions Outputs from Diesel Engines

Energy efficiency and environmental impact have become dominant topics in internal combustion engines development. Among many strategies to improve power and emissions outputs from diesel engines is the partial mix of hydrogen and air as fresh charge components to form extremely lean and homogenous mixture, which resist the spontaneous combustion, while diesel fuel is injected directly inside combustion chamber using the conventional fuel injection systems. This contribution presents an analytical and experimental investigation for the effects of adding hydrogen on diesel engines power output and the reduction of emissions. Parametric analysis is used based on lamped parameters modeling of intake manifold to estimate in cylinder trapped charge. The fuel energy flow to engine cylinders is compared for a range of loads and concentrations to simulate relevant case studies. Diesel fuel reduction for significant range of part-load operation can be achieved by introducing hydrogen, along with power improvement emission reductions are affected positively as well. This is achievable without compromising the engine maximum efficiency, given that most engines are operated at small and part-load during normal driving conditions, which allow for introducing more hydrogen instead of large quantities of excess air during such operation conditions that also can be further improved by charge boosting.

米勒循环对柴油机燃用生物柴油的性能研究

借助GT-Power软件实现某机车柴油机仿真模型的搭建,采用试验对仿真模型的准确性进行分析验证。研究在75%负载1000r/min工况燃用5种生物柴油B0、B10、B20、B50和B100,分析采用两种米勒循环对柴油机油耗、功率以及排放功能的影响。试验结果表明:柴油机功率发生变化拐点在30℃A米勒度处,油耗变化拐点在30℃A米勒度,碳烟排放发生变化拐点在20℃A米勒度,在该工况条件下NOx排放降低的效果较为显著。综合分析可知,在75%负载1000r/min工况条件下燃用B10生物柴油,米勒度为30℃A且变气阀重叠角米勒循环下柴油机表现最为佳。

针对功率降低的农用柴油机性能优化技术

分析了农用柴油机配气系统、燃油供给系统以及润滑系统的常见故障及其对功率的影响,提出相应的优化措施。通过农用柴油机使用者的培训和教育、改善柴油燃烧质量、针对性优化农用柴油机构造、调整过量空气系数等手段,能有效提高农用柴油机的功率输出和使用寿命。

DPF炭烟和灰分加载对不同增压系统柴油机性能的影响

基于某直列6缸增压柴油机试验台架,构建了柴油机+DPF的一维热力学仿真模型,研究了DPF炭烟和灰分加载对不同增压系统柴油机性能的影响。研究结果表明,DPF炭烟和灰分加载会导致单级增压(1TC)和二级增压(2TC)柴油机排气背压升高,进气充量降低,从而导致动力性下降,有效燃油消耗量升高,NO x排放量下降,soot排放量增加。炭烟因其深床炭烟层和较低的渗透率有利于捕集颗粒,提高了DPF捕集效率;而灰分由于其存在灰分堵头降低了孔道有效过滤长度,导致DPF捕集效率下降。DPF炭烟和灰分加载导致1TC柴油机扭矩和燃油消耗率在1000 r/min分别下降22.8%和29.6%,在2200 r/min分别下降2.1%和2.2%;而2TC柴油机扭矩和燃油消耗率在1000 r/min分别下降6.7%和7.1%,在2200 r/min分别下降10.7%和11.9%。二级增压可以降低DPF炭烟和灰分加载对柴油机性能的影响。

船用柴油机均值模型建模及仿真研究

柴油机模型的研究是探究柴油机性能、实现虚拟仿真的基础,可缩短仿真计算时间、有效节约柴油机开发成本。本文以RK270柴油机为研究对象,使用GT-POWER软件建立稳态性能仿真模型,在此基础上,采用仿真精度高、计算速度快的平均值法,以C++语言建立柴油机平均值模型,并归纳通用的平均值模型建模标定校核流程;提出二元响应拟合的方法,解决了涡轮增压器特性参数处理困难的问题,并借助数学工具,获得了压气机主要工作区域内拟合精度较高的模型。完成模型开发后,分析了8组工况下的仿真结果,通过误差分析,验证了模型的准确性,丰富完善了柴油机建模理论和方法,可应用于实时控制模型的动态仿真或者实现与船舶动力系统的交互。

等温加热修正Diesel循环及其内可逆特性

提出一种新的Diesel循环,即等温加热修正的Diesel循环,并运用有限时间热力学理论建立内可逆修正Diesel循环模型,导出循环功率与效率、功率与压缩比和效率与压缩比的特性关系,研究循环温比、预胀比和传热损失对循环性能的影响,将修正后的循环性能与传统的Diesel循环性能进行比较。结果显示:循环功率与效率的关系曲线呈扭叶型,而功率与压缩比和效率与压缩比的关系曲线均呈类抛物线型;随着预胀比和循环温比的变大,循环性能明显提升;与传统的Diesel循环相比,修正后的循环性能更优。

基于GT-Power的DPF喷油催化燃烧再生仿真技术

利用GT-Power软件建立DPF喷油催化燃烧再生系统仿真模型,从喷油率和补气策略两方面对DPF提温过程进行优化,优化后的DPF提温时间缩短了37.9%,DPF出口最高温度增加了3.4%.通过建立DPF微粒燃烧模型,分析了再生微粒燃烧过程中载体壁面温度及微粒(PM)层厚度分布情况.计算结果表明,载体温度由前端向后依次升高,最高温度出现在载体后端中心;微粒由载体前端向后逐渐燃烧,后端微粒燃烧速度快于前端.

基于GT-POWER的柴油机排放仿真分析

柴油机以其热效率高(高出汽油机20%)、适应性好、输出功率大等优点,应用范围越来越广。本文应用GT-POWER软件建立某型船用柴油机系统仿真模型,得到柴油机排放NOx仿真值,通过与实验值对比分析,验证计算机仿真技术在柴油机试验中的可靠性。结果表明。

基于工况协同的大功率柴油机循环性能优化

建立某型大功率柴油机的三维仿真模型并进行实验验证,基于验证模型的仿真结果对该型大功率柴油机循环工况的整体性能进行优化,在优化过程中提出“正向工况”和“协同工况”的概念和确定方法。结果表明,在仅对喷油角度进行调整的情况下,通过“正向工况”和“协同工况”间多工况的协同匹配,在保持循环比油耗基本不变时,循环NOx排放相比原机降低了6.43%;在保持循环NOx排放基本不变时,循环比油耗相比原机降低了1.53%,降幅达到3.18 g/(kW·h)。本研究提出的优化方法和过程对大功率柴油机循环工况或多工况整体性能的优化具有指导意义。

基于GT-power和Simulink的相继增压切出过程仿真研究

相继增压的动态切换特性对发动机性能有着重要的影响。为了研究相继增压系统空气阀相对燃气阀延迟关闭时间对切出过程柴油机性能的影响,建立了基于GT-power和MATLAB/Simulink的联合仿真平台。采用GT-power软件建立了TBD234V12柴油机仿真模型,MATLAB/Simulink软件建立了调速器、相继增压控制器和增压器喘振指数监测器仿真模型。对不同的阀门响应时间和空气阀延迟时间进行了相继增压柴油机切出过程瞬态仿真计算,结果表明切出过程中适当的空气阀延迟时间可以明显改善切出过程柴油机稳定性和排放,阀门响应时间增加会使柴油机性能和排放恶化。通过仿真计算确定了最佳的阀门控制策略。

基于GT-Power的柴油机仿真及优化

通过试验对柴油机进行优化,需耗费大量的人力、物力及财力,利用内燃机工作过程模拟软件GT—Power建立了柴油机仿真模型,对不同转速的配气相位进行了优化,得出相应转速下最佳配气相位,提出了一种新的改善柴油机性能的设计方案——燃油预热,并进行了模拟计算。计算结果表明:优化后的柴油机动力性得到了较大的提升,所提出的优化方案可以为柴油机改进和设计提供依据。

基于GT-Power的柴油机微粒捕集器的性能模拟研究

使用GT-Power软件,对柴油机微粒捕集器(DPF)的捕集性能进行了模拟仿真。建立了柴油机微粒捕集器的仿真模型,研究了DPF不同的结构参数对其捕集性能的影响。结果表明,体积、通道密度、过滤体的孔隙率、过滤体的微孔直径以及过滤体壁厚主要影响DPF的捕集效率;影响微粒捕集器压降的主要参数有,通道密度、过滤体微孔直径、体积以及过滤壁厚度。这为DPF设计提供了理论依据。

GT-Power在机车柴油机上的仿真应用

利用GT-Power搭建了直喷式四冲程增压柴油机的仿真平台,其中包括16缸模型、进排气管路模型、涡轮增压器模型和中冷器模型.并在机车用大功率重载增压柴油机16V240ZJ型发动机上进行了工作过程模拟计算验证,计算结果与实验结果吻合良好,误差较小.可见,利用GT-Power软件建立仿真计算模型这种方法,为机车柴油机的性能研究提供便利.

船舶柴油动力系统的多工况数学建模研究

本文研究船舶柴油机动力系统,重点分析船舶柴油机的动力装置,给出船舶柴油发电机转速和输出功率之间的关系曲线,并构建出船舶柴油机推进负载,分析船舶螺旋桨转矩和转速之间的曲线关系;构建船舶柴油机动力系统多工况数学模型;对模型进行仿真,并对柴油机中的燃烧率、压强以及扭矩进行分析;构建的船舶柴油机动力系统多工况数学模型,对我国船舶柴油动力系统的快速发展具有借鉴作用。

基于GT-Power柴油机性能仿真分析

利用计算机仿真进行机械结构设计是现代制造领域的重要方法之一,其目的是优化产品结构,减少应力集中,满足设计需求。应用GT-POWER软件建立某型船用柴油机系统仿真模型,得到柴油机功率仿真值,通过与实验值对比分析,验证计算机仿真技术在柴油机试验中的可靠性。结果表明,柴油机计算机仿真数据与实验数据相差不大,特别是在发动机常用区域,仿真数据能较好地反映柴油机的性能。