计及风电和小水电的发电系统可靠性评估研究

根据分布式电源随机输出功率的特点,利用集群技术,将较多的机组出力状态集合成较少的组群,建立了风电多容量机组可靠性模型和小水电机组改进的双状态模型。针对现有发电系统停运容量模型存在计算繁琐的问题,运用停运容量预备表优化排序,减省计算步骤和时间。将容量模型和日尖峰负荷模型结合,形成新型发电系统的裕度评估体系,采用某含多风电场和遍布小水电的地区的发电系统作为算例,编制MATLAB程序计算了一系列可靠性指标,定量分析了分布式电源对发电系统可靠性的影响。     

基于状态转移矩阵的小水电机组发电系统可靠性评估

作为我国重要的电力资源,小水电机组大规模并网运行给发电系统乃至整个电网可靠性与安全运行带来新的挑战。由于小水电数量众多,容量不等,采用现有递推公式建立停运容量模型来进行小水电机组发电系统可靠性评估时步骤繁琐,中间数据多,工作量大,对此提出了一种基于状态转移矩阵的小水电发电系统可靠性算法,用状态空间图表示小水电机组停运容量模型,基于状态空间算法直接计算小水电机组各个停运容量状态的确切概率,由转移率矩阵适当变换求取增量频率,用分块矩阵组合表示小水电机组停运容量模型和负荷容量模型的组合,合并相同容量状态,增加等步长而未出现的容量状态,即得小水电发电系统的裕度容量模型,进而计算累积概率、累积频率等可靠性指标。算例分析验证了此算法的可行性,可在实际操作中推广应用。     

大型CFB锅炉冷渣器结焦故障的分析与处理

以安徽临涣一期工程300MW循环流化床锅炉为例,分析锅炉冷渣器运行中结焦的原因,采取了对应的运行调整和检修维护措施后,冷渣器回路故障率降低,机组非计划停运次数大幅减少,机组运行可靠性和经济性明显提高。     

分布式燃气电站综合能源项目经济性分析

在传统火电向新能源转型的特殊时期,分布式燃气电站综合能源项目由于灵活的启停调峰特性和较 好的经济性,发挥得桥梁作用和在电力中的支撑作用将更加凸显。本文对分布式燃气电站综合能源项目的 作用和经济性进行分析,为天然气发电在新时期的发展提供了新的思路。     

单库单向运行潮汐电站发电量最大化计算模型及应用

潮汐电站一直存在资源利用率不高的问题,在电站建设初期当机组选型确定时,制定合理的水库蓄、放水计划,可在不增加投资的前提下获得更多的发电效益。为此,以国内某潮汐电站为例,根据各时刻机组发电流量的不同制定运行方案,基于动态规划法建立了单库单向运行潮汐电站发电量最大化计算模型,并利用龙格库塔算法,结合Matlab软件模拟了各时刻水库水位变化过程,求解了各运行方案的发电量值。计算结果表明,受潮汐水位及机组特性的控制,电站发电量的多少取决于发电流量在各时刻的分配,流量最大运行方案发电量明显大于效率最优运行方案,而发电量最大运行方案流量分配介于效率最优运行和流量最大运行之间。     

燃煤电厂湿法脱硫故障数据及可靠性分析

以西南地区多台燃煤机组的运行数据为基础,详细分析了石灰石石膏湿法脱硫设备的运行情况,计算对比了不同机组容量、锅炉型式、燃煤含硫量、GGH的优化改造和旁路烟道设置与脱硫系统故障之间的关系,并进一步估算了不同类型机组脱硫系统的非计划停运率,以此作为评判其可靠性的依据。结果表明,脱硫系统中的烟气再热器(GGH)以及增压风机发生故障的次数最多,时长最长。600 MW等级前后墙对冲型式锅炉机组的脱硫系统非计划停运率最高,其次是300 MW等级W型锅炉机组,而1 000 MW等级机组以及循环流化床机组最为稳定;各大机组脱硫系统在GGH改造优化和取消旁路之后故障时长明显减少;此外入炉煤的含硫量会直接影响脱硫系统的故障时长,设计含硫量在0.5%~1.0%等级的600 MW机组可靠性最低。     

燃气发电机组润滑油失效原因简析

燃气发电机组作为燃气电站的动力设备,良好的润滑系统是保证其可靠、稳定、连续运转的关键。本文针对燃气发电机组燃料成分的多样性、燃烧特性、机组运行过程因素等方面,分析造成润滑油失效的原因,以减少因燃气应用造成的该类故障,促进这类清洁能源在燃气内燃机发电行业的综合利用。     

150MW循环流化床锅炉节能分析

以唐山开滦东方发电有限责任公司150MW CFB锅炉机组为例,通过分析影响CFB锅炉运行的主要因素,在CFB锅炉中修中采取了三项受热面防磨改进措施,有效地减少或避免了锅炉机组非计划停运,并对冷渣器系统节能改造和锅炉排烟余热深度回收方案进行了分析。其分析结果可为CFB锅炉的设计和运行提供借鉴和参考。     

补燃型双压自然循环燃机余热锅炉

燃气-蒸汽联合循环电站是目前国际上发展最快的发电形式，由于燃气轮机具有体积小，重量轻，功率大，自动化程度高，操作简单等优点，所以采用燃气-蒸汽联合循环电站发电更具有高效清洁、建设周期短、操作运行方便，调峰能力强等优点。随着我国石油、天然气的大量开发和我国经济的快速发展，燃气-蒸汽联合循环发电的应用正在与日俱增，对改善我国的电力供应和环境保护具有重大意义。     

燃气发电主要能耗对标方法研究与应用

近年来燃气发电突飞猛进发展,装机容量翻倍增加,容量等级、安装型式等多样化,在燃气发电效率高于煤机的同时,仍需考虑通过行业对标管理,进一步提高机组整体效率,提高机组的可靠性和经济性。本文提出100 MW等级以上燃气-蒸汽联合循环发电主要能耗指标供电标准气耗的一种对标方法,考虑不同容量等级机组的当地气温条件、燃料成分、出力系数、启动次数、供热方式、冷却方式、老化因素及入厂天然气增压系统等边界条件,根据各边界条件对供电标准气耗的影响,将实际完成值折算进行对标,分析同容量等级机组的能耗水平的优势与差距,有利于提高整个燃气发电行业的能耗水平。     

Asymmetric information in the German intraday electricity market

This paper investigates how private and public information about unplanned power plant outages impact intraday electricity prices in Germany. It uses data from the EPEX day-ahead and continuous intraday markets as well as market messages concerning unscheduled power plant non-usabilities from the European Energy Exchange (EEX) transparency platform. The results of an econometric analysis suggest that private and public information about unplanned power plant outages have a significant positive effect on the intraday price.Furthermore, this paper shows that a reduction of the lead time on the intraday market enhances the possibilities of traders reacting to unplanned non-usabilities: an increased impact of private information on the electricity price is observed. The results also confirm an asymmetric impact of private and public information on the intraday price after the lead time reduction on the power exchange. The findings contradict the main objectives of the Regulation on Wholesale Energy Market Integrity and Transparency (REMIT), which stipulates that the possession of private information must not have an impact on electricity prices.     

Modeling of solid oxide fuel cells for dynamic simulations of integrated systems

Solid oxide fuel cell (SOFC) stacks are at the core of complex and efficient energy conversion systems for distributed power generation. Such systems are currently in various stages of development. These power plants of the future feature complicated configurations, because the fuel cell demands for a complex balance of plant. Moreover, proposed SOFC-based systems for stationary applications are often connected to additional components and subsystems, such as a gasifier with its gas-cleaning section, a gas turbine, and a heat recovery system for thermal cogeneration or additional power production. For the simplest SOFC configurations, and more so for complex integrated systems, the dynamic operation of the power plant is challenging, especially because the fluctuating electrical load of distributed energy systems demand for reliable transient operation. Issues related to dynamic operation must be studied in the early design stage and simulation results can be used to optimize the system configuration, taking into account transient behavior. This paper presents the development and the validation of a non-linear dynamic lumped-parameters model of a SOFC stack suitable for integration into models of complex power plants. Particular emphasis is placed on the systematic approach to model development. The model is implemented using the open-source Modelica language, which allows for a high degree of flexibility and modularity, the main features of the model herein presented. The SOFC stack model will be incorporated into ThermoPower, a freely distributed library of reusable software components for the modeling of thermo-hydraulic processes and power plants.     

Impact of distributed and independent power generation on greenhouse gas emissions: Sri Lanka

Sri Lanka has a hydropower dominated power system with approximately two thirds of its generation capacity based on large hydro plants. The remaining one third are based on oil fired thermal generation with varying technologies, such as oil steam, Diesel, gas turbines and combined cycle plants. A significant portion of this capacity is in operation as independent power plants (IPPs). In addition to these, Sri Lanka presently has about 40 MWs of mini-hydro plants, which are distributed in the highlands and their surrounding districts, mainly connected to the primary distribution system. Further, there are a few attempts to build fuel wood fired power plants of small capacities and connect them to the grid in various parts of the country.

The study presented in this paper investigates the impact of these new developments in the power sector on the overall emissions and the greenhouse gas (GHG) emissions in particular. It examines the resulting changes to the emissions and costs in the event of developing the proposed coal power plant as an IPP under different investment and operational conditions. The paper also examines the impact on emissions with 80 MWs of distributed power in different capacities of wind, mini-hydro and wood fired power plants.

It is concluded that grid connected, distributed power generation (DPG) reduces emissions, with only a marginal increase in overall costs, due to the reduction in transmission and distribution network losses that result from the distributed nature of generation. These reductions can be enhanced by opting for renewable energy based DPGs, as the case presented in the paper, and coupling them with demand side management measures. It is also concluded that there is no impact on overall emissions by the base load IPPs unless they are allowed to change over to different fuel types and technologies.     

On the operation strategy of steam power plants working at variable load: Technical and economic issues

The context of the deregulated energy market leads to high competitiveness among producers and requires suitable strategies in plants and systems management: strongly irregular and discontinuous operation is required in order to meet the user demand and produce energy mainly during peak hours, when the electricity price is higher. This operation strategy is generally asked of all power plants, not only those traditionally devoted to load regulation and peak request, but also those originally designed to cover the base load (steam power plants, for example). As a consequence, greater income is ensured in the short term, but a reduction in the lifetime of the most critical components is likely to occur, due to creep and thermo-mechanical fatigue loadings. This will cause additional costs associated with unplanned maintenance and unavailability of the plant if a failure occurs.This paper presents a procedure aimed at evaluating this extra cost related to flexible operation, and at assisting the management decision about power plants’ operation and maintenance scheduling. The procedure, on the basis of the historical data, predicts the residual life of the most critical components, considering the effects of creep, thermo-mechanical fatigue, welding, corrosion and oxidation. It also permits one to choose different future strategies for plant management and evaluate the residual life and the economic effects for each of them. An example of application to a real steam power plant will also be presented.     

Experiences of automatic contingency selection algorithms on theNGC system

An essential aspect of modern power system security assessment is the consideration of any contingencies which may arise due, for example, to planned or unplanned outages of lines, and which may cause system overloads or abnormal system voltages. Several methods have been developed during the last few years to address this problem and within the National Grid Company, the ΔP²X outage ranking process has been used in the past. However, this ΔP²X outage ranking method may not identify those critical outages associated with relatively low ΔP²X changes. The paper reports on investigations carried out to determine which simplified methods would ensure that all voltage-based severe outages were identified     

微型燃气轮机技术

高效微型燃气轮机发电机组可用于航空、航天等领域,还可用于分布式发电、军用车辆辅助动力装置、车用混合动力装置等,因此研究这种动力装置有重要的实用意义。首先介绍了微型燃气轮机的发展过程,简要说明了过去40年内微型燃气轮机在结构上发生的变化,随后给出了组成微燃气轮机的关键部件在设计过程中应注意一些问题。最后回顾了国内一些研究单位在这一领域所进行的研究工作,并指出今后的努力方向和工作重点。     

Potential evaluation of power-to-hydrogen-to methane conversion technology in robust optimal energy management of a multi-energy industrial park

Multi-energy industrial parks are required to render a huge variety of services in an eco-friendly, secure, reliable, and affordable way. The industrial energy park is a separate area consisting of multiple distributed generations, energy storage systems, etc., which supply local gas, heating, and electrical consumers. Meanwhile, the integration of power-to-X technologies such as power-to-gas and power-to-heat, which convert the electricity into other forms of energies while facilitating the integration of renewable energy in the industrial park, can enhance the flexibility and efficiency of energy supply. Therefore, this paper proposes novel robust energy management of multi-energy industrial parks integrated with wind power resources, cogeneration units, power-to-X technologies, and demand response programs to total operation cost minimization. The industrial park can simultaneously participate in a multi-energy market, including power, thermal, and gas markets, to meet local heating, gas, and electrical load. The robust optimization framework is extended to address the power price uncertainty and manage the conservatism level of the operator against price variability. The proposed model is examined on the industrial park test system, and numerical results will be presented for the different cases. Under the robust energy management, the total operation cost of the multi-energy industrial park reduces up to 53 %.     

GREENHOUSE GAS ANALYSIS OF SOLAR-THERMAL ELECTRICITY GENERATION

Solar-thermal electricity generation contributes to climate change because it incurs the emission of greenhouse gases during the provision of services and the production of materials needed for the construction and operation of solar power plants. These greenhouse gas costs (GGC) can be determined using either material inventories in physical units or monetary cost breakdowns. Solar-only plants employing parabolic troughs, central receivers or parabolic dishes exhibit GGC around 90 g CO₂-e/kWh_el. However, this figure varies with the plant size and also depends strongly on whether a fossil-fuelled backup or a heat storage system is utilised in order to increase the plant’s capacity factor.     

Decentralised optimisation of cogeneration in virtual power plants

Within several projects we investigated grid structures and management strategies for active grids with high penetration of renewable energy resources and distributed generation (RES & DG). Those ”smart grids” should be designed and managed by model based methods, which are elaborated within these projects. Cogeneration plants (CHP) can reduce the greenhouse gas emissions by locally producing heat and electricity. The integration of thermal storage devices is suitable to get more flexibility for the cogeneration operation. If several power plants are bound to centrally managed clusters, it is called “virtual power plant”. To operate smart grids optimally, new optimisation and model reduction techniques are necessary to get rid with the complexity.There is a great potential for the optimised management of CHPs, which is not yet used. Due to the fact that electrical and thermal demands do not occur simultaneously, a thermally driven CHP cannot supply electrical peak loads when needed. With the usage of thermal storage systems it is possible to decouple electric and thermal production. We developed an optimisation method based on mixed integer linear programming (MILP) for the management of local heat supply systems with CHPs, heating boilers and thermal storages. The algorithm allows the production of thermal and electric energy with a maximal benefit. In addition to fuel and maintenance costs it is assumed that the produced electricity of the CHP is sold at dynamic prices. This developed optimisation algorithm was used for an existing local heat system with 5 CHP units of the same type. An analysis of the potential showed that about 10% increase in benefit is possible compared to a typical thermally driven CHP system under current German boundary conditions. The quality of the optimisation result depends on an accurate prognosis of the thermal load which is realised with an empiric formula fitted with measured data by a multiple regression method.The key functionality of a virtual power plant is to increase the value of the produced power by clustering different plants. The first step of the optimisation concerns the local operation of the individual power generator, the second step is to calculate the contribution to the virtual power plant. With small extensions the suggested MILP algorithm can be used for an overall EEX (European Energy Exchange) optimised management of clustered CHP systems in form of the virtual power plant. This algorithm has been used to control cogeneration plants within a distribution grid.