Reliability analysis of grid connected small wind turbine power electronics

Grid connection of small permanent magnet generator (PMG) based wind turbines requires a power conditioning system comprising a bridge rectifier, a dc–dc converter and a grid-tie inverter. This work presents a reliability analysis and an identification of the least reliable component of the power conditioning system of such grid connection arrangements. Reliability of the configuration is analyzed for the worst case scenario of maximum conversion losses at a particular wind speed. The analysis reveals that the reliability of the power conditioning system of such PMG based wind turbines is fairly low and it reduces to 84% of initial value within one year. The investigation is further enhanced by identifying the least reliable component within the power conditioning system and found that the inverter has the dominant effect on the system reliability, while the dc–dc converter has the least significant effect. The reliability analysis demonstrates that a permanent magnet generator based wind energy conversion system is not the best option from the point of view of power conditioning system reliability. The analysis also reveals that new research is required to determine a robust power electronics configuration for small wind turbine conversion systems.     

世界主要风电生产国的并网电价

在世界一些地区,风电已经占据能源供应的很大比例。例如丹麦,风电已经占全国电力消耗总量的20%;在德国的几个联邦州,例如施勒苏益格·荷尔斯泰因州、下萨克森州和萨克森·安哈尔特州,风电已能满足这些州电力需求的25%以上;在西班牙的某些省,风电甚至可满足这些省几乎100%的电力供应。     

海上风电场并网后的潮流计算研究

根据海上风电机组的特点,建立了简化的异步发电机组等效稳态模型。考虑海上风能速度与发电机组的有功功率、机端电压、无功功率以及滑差率的关系,设计出有大型海上风电场并网的电力系统潮流计算方法;并通过电力系统分析综合程序(PSASP)的用户程序接口(UPI)调用动态连接库文件,进行系统的潮流计算;最后通过PSASP自带的WSCC9节点系统验证了设计的可行性。     

风电并网后系统备用的相关问题综述

文章阐述并分析了风电并网后对电力系统备用容量的确定、获取和费用分摊的影响,以及风电并网后系统备用相关问题研究的必要性,提出了对上述各方面进一步研究的思路和方法,为实现风电并网系统安全经济运行提供一些参考。     

Assessment of wind power potential for turbine installation in coastal areas of Turkey

This paper analyses the potential and the feasibility basis for the wind energy resources in some locations of coastal regions of Turkey. The dominant wind directions, the mean values, wind speeds, wind potential and the frequency distributions were determined. The results showed that Bal?kesir and Çanakkale among annual averages show higher value of mean wind speed. The mean annual value of Weibull shape parameter k is between 1.54 and 1.86 while the annual value of scale parameter c is between 2.52 m/s and 8.34 m/s. A technical assessment has been made of electricity generation from four wind turbines having capacity of 600 kW, 1500 kW, 2000 kW and 2500 kW. The yearly energy output and capacity factor for the four different turbines were calculated.     

Production price of hydrogen from grid connected electrolysis in a power market with high wind penetration.

In liberalized power markets, there are significant power price fluctuations due to independently varying changes in demand and supply, the latter being substantial in systems with high wind power penetration. In such systems, hydrogen production by grid connected electrolysis can be cost optimized by operating an electrolyzer part time. This paper presents a study on the minimization of the hydrogen production price and its dependence on estimated power price fluctuations. The calculation of power price fluctuations is based on a parameterization of existing data on wind power production, power consumption and power price evolution in the West Danish power market area. The price for hydrogen is derived as a function of the optimal electrolyzer operation hours per year for four different wind penetration scenarios. It is found to amount to 0.41–0.45 €/Nm³. The study further discusses the hydrogen price sensitivity towards investment costs and the contribution from non-wind power sources.     

Forecasting the diffusion of wind power in Pakistan

About half of the Pakistan’s population has no access to electricity and per capita consumption is one of the lowest in the world. The country is facing severe energy crisis due to shortage of electricity and gas supply. About two-third of the total electricity is generated from fossil fuels. Pakistan heavily depends on imported energy due to limited indigenous reserves and production of oil. The production, transportation, transformation and consumption of fossil fuels also adversely affect the quality of the environment due to indiscriminate release of toxic substances. This shows that Pakistan must develop alternate, indigenous and environment friendly energy resources, like wind energy, to face these challenges. This paper presents the market penetration forecasts of wind power in Pakistan under different policy scenarios. The diffusion of wind power is forecasted using logistic model and analogous approach. The study concludes that about 42, 58 and 73% of the country’s total technical potential of wind power generation could be exploited by the year 2030 under SS, MS and OS scenarios respectively. The development and utilization of wind power would reduce the pressure on oil imports, protect the environment from pollution and improve the socio-economic conditions of the people of Pakistan.     

风电入网风险量化及对电力系统优化调度影响

随着风电并网容量的持续增加,风电随机性给电力系统运行带来的风险也不断增加,传统经济调度方法已经难以满足电力系统安全运行需求。文章对风电不确定性带来的运行风险及节能减排的贡献进行量化研究,将量化所得的发电成本、环境成本及系统运行风险作为调度特征量,构建同时考虑发电资源消耗最少、环境效益最好和系统运行风险最小的多目标优化调度模型。以某地区电网为例,应用非线性原-对偶内点法对所建模型进行求解,分析风电入网系统运行风险、风电穿透功率对调度计划的影响及不同的调度特征量对总成本的影响,验证本文所建模型的合理性和有效性。     

基于DSP实现风力发电机组并网运行

提出了一种风力发电机组并网运行系统;研究了基于数字信号处理器-DSP(TMS320F240)控制的发电机转速驱动控制系统;详细介绍了该系统的DSP控制器的硬件电路设计,实现了对发电机转轴的速度检测和滑差离合器励磁线圈的电流检测;最后给出了该系统的软件设计方案及控制策略,完成对整个系统的控制,使发电机转速稳定,且输出稳定的频率和电压.     

风电系统的无功功率与电网电压稳定

论述了风电容量在占局部电网相当比例时,风电机组的无功功率调整与电网电压之间的关系,对于定速和变速风电机组的运行特性做了分析,提出了在需要做无功功率调整时风电机组应能满足的特殊要求。     

Operational simulation of wind power plants for electrolytic hydrogen production connected to a distributed electricity generation grid

Two procedures are analyzed to control the flow of hydrogen produced by an electrolyzer in a plant connected to a distributed electricity grid. The general idea of both procedures is to approximate the consumption power of the electrolyzer to the tracked hourly mean useful power of a wind generation system. The first technique uses a perceptron to predict hourly wind-speed values as the basis for the power consumption of the electrolyzer. The second approximates the hourly consumption of the electrolyzer to the useful power of the wind generation system over the previous hour. Calculations have shown that the control procedure, using either one of these two techniques, leads to substantial improvements in the main parameters of the plant, compared to an installation in which electrolyzer consumption is constant. In particular, the number of batteries in the accumulation system may be reduced. Moreover, considering the possibility that the hydrogen production plant might supply electricity to the external electricity grid, various objectives for operational optimization of the installation are analyzed. A function that defines the joint exploitation of the wind energy by the electrolyzer and the external electricity grid is introduced and then, by using that function, an optimal operating regime for the plant is determined.     

基于风光互补电力入网的电力系统动态经济调度

为解决风光互补电力入网的不确定性给电网调度带来的影响,文章对其的经济调度问题进行研究。针对火电机组的排污特性引入了环境污染惩罚成本,针对风光电力输出功率的间歇波动性引入了备用容量惩罚成本,在考虑系统供需平衡与机组爬坡率等约束条件的基础上,给出了风光电力互补入网的调度策略,建立了含有风光互补电力的动态经济调度模型;应用一种改进的粒子群算法对所提模型进行求解。最后以IEEE-30节点测试系统为例进行仿真分析,仿真结果验证了所提模型的合理性及算法的有效性,同时也说明了风光互补电力入网能够平抑风电的出力波动,可以在保证系统可靠性的基础上,提高风光电力的并网率。     

郭煌8MWp并网光伏发电系统預司行性研究

太阳能光伏发电技术已经成熟、可靠、实用，光伏电池使用寿命已经达到25～30年。     

Fault ride through and voltage regulation for grid connected wind turbine

High penetration of wind generation challenges wind turbine operators to supply reliable power and extract optimum power from the wind. Hence, the fault ride through (FRT) capability of wind turbine together with the optimum power tracking and regulation of wind turbine output voltage due to fluctuating nature of the wind becomes essential. In this paper, a method is proposed to ensure that the double fed induction generator (DFIG) wind turbine continues to operate during severe grid faults and maintains a constant output voltage, irrespective of the fluctuating wind. The proposed controller also allows the DFIG wind turbine to track optimum power from the wind. Extensive simulation is performed using PSCAD/EMTDC software and results obtained show that the DFIG output voltage fulfills the grid code requirements. The results also show that the proposed method is able to track the optimum power, regulate the DFIG output voltage and perform fault ride through of wind turbine.     

全球风电成本的初步分析

通常，风电被认为在经济性上没有什么竞争力。但，据Poul Erik Morthorst和Hugo Chandler两位的统计，在过去的15年里，风电的实际成本已经下降了50％之多，而且这种趋势还在继续。     

Probabilistic capacity of a grid connected wind farm based on optimization method

This paper proposes a new method to find the capacity of a future wind farm regarding several limits of the grid system: voltage stability limits, thermal limits, voltage limits, load tap changing limitation and generator power output limitation. The method combines the optimization method and a probabilistic analysis to maximize the number of the wind turbines subject to those limits. Two types of wind farms are modeled in this paper: fixed speed wind farms and variable speed wind farms. It is concluded that the proposed method is a fast and accurate method to deal with the uncertainty of wind energy in the planning of wind farm capacity.     

并网风电机组寿命分布拟合与维修方案评价

风电机组的寿命分布是制定维修策略和优化机组运行的重要依据,研究其寿命分布需要大量的完整寿命数据,然而我国风电机组投入运行的时间短,缺少完整寿命数据。文章首先提出了一种基于部件寿命信息的机组可靠寿命分布拟合方法,该方法根据部件运行寿命信息和机组系统可靠性框图,模拟产生机组的可靠寿命;然后利用灰色关联度定量地选择机组寿命分布拟合函数,对机组的可靠寿命进行分析;最后利用机组可靠寿命分布,提出了基于机组可靠度测度维修方案的量化分析模型。研究结果表明,风电机组寿命分布可用威布尔分布拟合;文章所提出的可靠度测度分析模型能够有效地评价机组维修方案的优劣。     

风力发电技术讲座(六) 风电场及风力发电机并网运行

风电场（即风力发电场）是大规模利用风能的有效方式.风电场是在风能资源良好的较大范围内,将几台、或几十台、或几百台单机容量数十千瓦、数百千瓦,乃至兆瓦的风力发电机,按一定的阵列布局方式,成群安装组成的向电网供电的群体.