非正常功率衰减光伏组件的发电量分析与研究

光伏组件是光伏电站的关键部件,其功率衰减将造成光伏电站的整体发电量下降,影响电站的效益。通过对连接有正常功率衰减光伏组件和非正常功率衰减光伏组件的2台逆变器的发电量数据进行分析,得出了非正常功率衰减光伏组件的衰减规律及衰减程度,可为以后深入研究提供参考。     

光伏组件温度损失控制和余热利用的研究

阐述了光伏电池组件温度损失控制、余热综合利用、余热利用实际案例。在国家环保政策趋于严格,企业节能减排、零排放、零污染和降本增效的背景下,通过对光伏组件温度损失控制和热能利用的研究,可降低事故发生概率,提高组件实际使用寿命,提高光伏实际发电量,为组件温度损失控制和余热综合利用的现场实证提供了方法和依据。     

锅炉有机热载体品质非正常变化的原因分析

在有机热载体锅炉系统中,有机热载体随着使用时间的增长,其品质呈缓慢下降趋势。通过连续两年导热油检验数据的对比分析,得出了影响导热油相关品质非正常变化的原因,以便有机热载体锅炉在日常运行中避免出现这些问题,使检验工作能够顺利开展。     

巢湖生态调水的水质约束条件

生态调水是巢湖水污染综合治理的一项重要措施,长江又是巢湖生态调水的水源区与排泄区,为确定长江和巢湖生态调水的水质重要约束条件,通过分析江(长江)湖(巢湖)水质数据、总结江湖水质变化规律和趋势、利用统计学中方差分析的方法,定量判断了各水域分月、分季水质差别。结果表明,长江水质总体较好,生态调水的水源不会对巢湖的水源地水质产生负面影响,但应考虑避免在冬季进行调水。     

改善巢湖市饮用水源地水质的调水方案比选

以改善巢湖市饮用水源地水质为目标,基于现状河道和水利工程,对比分析了长江与巢湖水质,研究了长江与巢湖水体交换规律、交换量及巢湖水位控制方案,拟定了不同线路、调水量、水位控制等多个调水方案,采用层次分析法比选了调水方案效果,并提出了实际调水应用的建议.结果表明,正向调水、7×108～13×108m3交换水量和晒滩水位控制...     

灰尘导致的光伏电站发电损失的对比实验

对地面光伏电站的2个采取不同清洁策略方阵的运行数据和辐照数据分成上午数据和下午数据,分别进行处理和分析.介绍去除数据集中的异常数据和不可信数据的预处理的方法.之后,对比组串的发电数据,发现了2个方阵中发电异常的2个组串.为了研究清洁增益的效果,计算不同太阳辐照度下2个方阵的功率比值.发现对于不同的辐照度,清洁增益的效果...     

矿车轮对非正常磨损原因分析及预防措施

轮对是矿车的关键部件．它既是行走机构又是承载机构。但在使用过程中因为轮对质量原因常出现掉道脱轨,甚至翻车。严重影响矿井的生产运输安全。通过对矿车轮对的非正常磨损原因分析,提出几种预防和改进措施,提高矿车轮对的使用年限。保证矿车的安全运行。     

平原河网调水引流水动力改善效果分析

为改善平原河网中水的流动情况,在太仓市主城区进行了原型调水试验,根据试验结果建立了符合太仓市主城区的河网非稳态水量数学模型,并以换水率为研究对象,分析了不同调水方案下太仓市主城区河网水体交换的改善情况。结果表明,受长江涨落潮影响的平原河网地区,调水可以有效改善河道的水体交换情况,引水方案改善效果优于排水方案;随着调水流量的增加,部分河道受来水相互顶托作用换水率降低。     

跨区域非固定调水市场博弈分析

针对目前我国调水市场机制存在的问题,探讨了利用市场机制协调调水市场各方利益,并通过分析调水市场将调水市场划分为非固定调水市场和协议调水市场,分析了非固定调水市场的纯战略帕累托均衡、混合战略纳什均衡及协议调水市场的合作博弈,通过寻求利益最大化,得出了均衡状态下的价格实例计算.实例计算结果表明,博弈分析对我国调水工程水价的制定和管理具有一定的理论意义和应用价值.     

考虑空气污染因素的光伏发电量回归分析

人类活动产生的大气污染物对到达地面的太阳总辐照和光谱分布都会产生一定影响。文章利用一座分布式电站的实测数据,通过模型回归分析的统计学方法,定量地研究了空气质量和光伏发电量之间的直接关联强度。同时,考虑了温度、风力、云量和太阳光入射角度等气象、物理参数对于光伏发电量的影响。利用该回归模型,可以根据公开气象资料对小型光伏电站的发电量进行简单预测。     

Evolution of China’s power dispatch principle and the new energy saving power dispatch policy

With social economic reform in the past decades, the power industry of China is gradually evolving from a highly integrated one toward an electricity market, which can be characterized based on the transition of the power dispatch principle. To attract investment in the power generating industry, China introduced non-state-owned power plants to the original system of a highly vertically integrated power industry with annual power generation quota guarantees, which makes the traditional economic dispatch principle not applicable. The newly debuted energy saving power dispatch (ESPD) is an attempt to fully exploit the maximum energy savings and was implemented by an administrative code. Starting in August 2007, the pilot operation of the ESPD was implemented in five provinces, but after two years, it is still not widely applied all over the country. This paper details the transition of China’s power dispatch principle with particular attention to its origin and content. Moreover, the factors that influence the ESPD’s actual energy saving effect are discussed, as well as the sustainability of the policy.     

Output power dispatch control for a wind farm in a small power system

Nowadays, a wind turbine generator (WTG) is required to provide control capabilities as the output power of WTG fluctuates. Under this scenario, this paper proposes an output power control method of a wind farm (WF) connected to a small power system using pitch angle control. In this control approach, the WF output power control is achieved by two control levels: central and local. In the central control, the WF output power command is determined by considering the frequency deviations and wind speeds using a fuzzy function. Then, the local output power commands for each of the WTGs are based on the proposed dispatch control. In the proposed dispatch control, the output commands of each WTG are determined by considering wind conditions for each of the WTGs. The simulation results by using an actual detailed model for the wind power system show the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

A method of economical load dispatch for steam turbine unit of thermal power plant

In this paper, by combining the equality differential increment theory (EDIT) with the equivalent polyhedron body (EPB) searching extremum strategy, a method of economical load dispatch for the steam turbine unit of the thermal power plant has been presented. Simultaneously, a method for the order of load shedding and the related optimal economic operational modes of each turbine unit in decreasing its load are ascertained. According to the methods, the results of the optimal economical dispatch of the peak loads, the order of load shedding and the related optimal economic operational modes of each turbine unit while decreasing the load of a certain thermal power plant have been obtained. These results are applied in the thermal unit, and its economic benefits are shown to be obviously higher than that of applying the relative efficiency of each turbine unit. The methods can be used as a reference for obtaining the optimum economical load dispatch for similar thermal power turbine units. Copyright © 2007 John Wiley & Sons, Ltd.     

煤矿自备电厂供用电系统线路优化的实践与分析

在保证煤矿用电安全的基础上,通过线路优化的方法,对某煤矿自备电厂供电线路进行了优化分析与研究。以去除多余供电设备、增加线路保护装置相结合的原则,对原供用电系统进行了优化改造。应用实践表明,供电系统线路优化是电力系统节能的有效手段,具有投资少、收益高、节能效果明显的优点,具有极大的应用价值和推广前景。     

Combined heat and power economic dispatch problem using the invasive weed optimization algorithm

Cogeneration units which produce both heat and electric power are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a feasible zone. Each point within the feasible zone consists of a specific value of heat and electric power. These units are used along with other units which produce either heat or power exclusively. Hence the economic dispatch problem for these plants optimizing the fuel cost is quite complex and several classical and meta-heuristic algorithms have been proposed earlier. This paper applies the invasive weed optimization algorithm which is inspired by the ecological process of weed colonization and distribution. The results obtained have been compared with those obtained by other methods earlier and showed a marked improvement over earlier ones.     

Enhancement of combined heat and power economic dispatch using self adaptive real-coded genetic algorithm

In this paper, a self adaptive real-coded genetic algorithm (SARGA) is implemented to solve the combined heat and power economic dispatch (CHPED) problem. The self adaptation is achieved by means of tournament selection along with simulated binary crossover (SBX). The selection process has a powerful exploration capability by creating tournaments between two solutions. The better solution is chosen and placed in the mating pool leading to better convergence and reduced computational burden. The SARGA integrates penalty parameterless constraint handling strategy and simultaneously handles equality and inequality constraints. The population diversity is introduced by making use of distribution index in SBX operator to create a better offspring. This leads to a high diversity in population which can increase the probability towards the global optimum and prevent premature convergence. The SARGA is applied to solve CHPED problem with bounded feasible operating region which has large number of local minima. The numerical results demonstrate that the proposed method can find a solution towards the global optimum and compares favourably with other recent methods in terms of solution quality, handling constraints and computation time.     

Reactive power dispatch in wind farms using particle swarm optimization technique and feasible solutions search

In this paper, an optimization method for the reactive power dispatch in wind farms (WF) is presented. Particle swarm optimization (PSO), combined with a feasible solution search (FSSPSO) is applied in order to optimize the reactive power dispatch, taking into consideration the reactive power requirement at point of common coupling (PCC), while active power losses are minimized in a WF. The reactive power requirement at PCC is included as a restriction problem and is dealt with feasible solution search. Finally an individual set point, particular for each wind turbine (WT), is found. The algorithm is tested in a WF with 12 WTs, taking into consideration different control options and different active power output levels.     

DF4型机车膨胀水箱水位上涨故障的原因及处理

分析了DF4型机车膨胀水箱水位上涨故障的原因,介绍了该故障的判断和处理方法。     

Economic emission dispatch: a case study of Myanmar

Economic load dispatch (ELD), used as part of the modern energy management system basically minimizes the total generation fuel cost of thermal plants while satisfying various system constraints. However, ELD alone is not sufficient to reduce the pollutant emissions caused by fossil fuel burning for power generation. Thus, it becomes necessary to implement economic emission dispatch (EED) model, which aims to minimize both generation fuel cost and emissions simultaneously. Myanmar Power System is used as a case study in this model. The types of emissions considered in the study are carbon dioxide (CO₂) and nitrogen oxides (NO_x). A practical ramp‐rate of turbine generator units is also formulated and studied in the model. Total emission constraint on the whole system is further implemented to investigate the effect of emission limit on the variation of generation schedule among generating plants. It is found that whenever minimum cost of operation is taken as sole objective in the model, the corresponding emission level increases. Similarly, minimum emission dispatch results in higher operating cost. Therefore, both objectives are conflicting in nature and some weights must be assigned to obtain a non‐inferior solution. The case where the ramp‐rate is considered in problem formulation incurs higher cost than that without it. Several trade‐off curves obtained can be taken as guidelines to fix the desired level of cost and emission together by the operators. Copyright © 1999 John Wiley & Sons, Ltd.