Bio-Inspired Optimal Dispatching of Wind Power Consumption Considering Multi-Time Scale Demand Response and High-Energy Load Participation

Bio-inspired computer modelling brings solutions fromthe living phenomena or biological systems to engineering domains.To overcome the obstruction problem of large-scale wind power consumption in Northwest China,this paper constructs a bio-inspired computer model.It is an optimal wind power consumption dispatching model of multi-time scale demand response that takes into account the involved high-energy load.First,the principle of wind power obstruction with the involvement of a high-energy load is examined in this work.In this step,highenergy load model with different regulation characteristics is established.Then,considering the multi-time scale characteristics of high-energy load and other demand-side resources response speed,a multi-time scale model of coordination optimization is built.An improved bio-inspired model incorporating particle swarm optimization is applied to minimize system operation and wind curtailment costs,as well as to find the most optimal energy configurationwithin the system.Lastly,we take an example of regional power grid in Gansu Province for simulation analysis.Results demonstrate that the suggested scheduling strategy can significantly enhance the wind power consumption level and minimize the system’s operational cost.

Quantitative method for evaluating detailed volatility of wind power at multiple temporal-spatial scales

With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to evaluate the volatility of wind power only consider its overall characteristics, such as the standard deviation of wind power, the average of power variables, etc., while ignoring the detailed volatility of wind power, that is, the features of the frequency distribution of power variables. However, how to accurately describe the detailed volatility of wind power is the key foundation to reduce its adverse influences. To address this, a quantitative method for evaluating the detailed volatility of wind power at multiple temporal-spatial scales is proposed. First, the volatility indexes which can evaluate the detailed fluctuation characteristics of wind power are presented, including the upper confidence limit, lower confidence limit and confidence interval of power variables under the certain confidence level. Then, the actual wind power data from a location in northern China is used to illustrate the application of the proposed indexes at multiple temporal(year–season–month–day) and spatial scales(wind turbine–wind turbines–wind farm–wind farms) using the calculation time windows of 10 min, 30 min, 1 h, and 4 h. Finally, the relationships between wind power forecasting accuracy and its corresponding detailed volatility are analyzed to further verify the effectiveness of the proposed indexes. The results show that the proposed volatility indexes can effectively characterize the detailed fluctuations of wind power at multiple temporal-spatial scales. It is anticipated that the results of this study will serve as an important reference for the reserve capacity planning and optimization dispatch in the electric power system which with a high proportion of renewable energy.

Videometric research on deformation measurement of large-scale wind turbine blades

Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.

Preliminary Feasibility Study on Application of Very Large Scale-Photovoltaic Power Generation in China

Some energy experts believe that solar energy photovoltaic power generation is hopeful to be applied in a large amount and possesses a certain proportion in the structure of energy in the future. In this paper, based on the forecasting of electric load demand and energy structure of power generation in the middle of 21 century, the pictures of VLS-PV power genera- tion is composed, the operation characteristic of VLS-PV power generation and the adaptability of electric power grid for it is analyzed, the ways for transmitting large amount of PV power and the economic and technical bottlenecks for applying VLS-PV power generation are discussed. Finally, the steps and suggestions for developing VLS-PV power generation and its electric power system in China are proposed.

Experimental study of rotating wind turbine breakdown characteristics in large scale air gaps

When a wind turbine is struck by lightning,its blades are usually rotating.The effect of blade rotation on a turbine＇s ability to trigger a lightning strike is unclear.Therefore,an arching electrode was used in a wind turbine lightning discharge test to investigate the difference in lightning triggering ability when blades are rotating and stationary.A negative polarity switching waveform of 250/2500 μs was applied to the arching electrode and the up-and-down method was used to calculate the 50%discharge voltage.Lightning discharge tests of a 1：30 scale wind turbine model with 2,4,and 6 m air gaps were performed and the discharge process was observed.The experimental results demonstrated that when a 2 m air gap was used,the breakdown voltage increased as the blade speed was increased,but when the gap length was 4 m or longer,the trend was reversed and the breakdown voltage decreased.The analysis revealed that the rotation of the blades changes the charge distribution in the blade-tip region,promotes upward leader development on the blade tip,and decreases the breakdown voltage.Thus,the blade rotation of a wind turbine increases its ability to trigger lightning strikes.

High-Resolution Micro-Siting Technique for Large Scale Wind Farm Outside of Japan Using LES Turbulence Model

The spatial distribution of wind speed varies greatly over steep complex terrain, thus the selection of an optimal site in such terrain for wind turbine construction requires great care. We have developed a numerical model for simulating unsteady flows called RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University, COM putational Prediction of Airflow over Complex Terrain), which is based on the LES (Large-Eddy Simulation) technique. The computational domain of RIAM-COMPACT can be varied from several meters to several kilometers, and the model is able to predict airflow over complex terrain with high accuracy. The present paper discusses the application of RIAM-COMPACT to the micro-siting of wind turbines at sites outside Japan. The results from two case studies will be presented.

A Scheme of Dynamic Voltage Restorer to Improve Power Quality in Large Scale Industrial Enterprises

Loads in large scale industrial enterprises are always various and complex, causing insecure power quality. Meanwhile, some sensitive loads or precise instruments demand for high power quality. When voltage flicker or harmonics occurs, dynamic voltage restorer (DVR) can be used to stabilize the load-side voltage, which is a good manner of improving power quality. The paper explains the load demand in large scale industrial enterprises, analyzes several common voltage compensation scheme of DVR, and comes up with another voltage compensation scheme of DVR applied for double power supply with double load. A Simulink model according to the new scheme is also built in MATLAB/Simulink to test its performance. Simulation results show that the proposed scheme can guarantee the load-side voltage stability, which is an effective scheme for managing power quality.

A Very Large Scale Wind Turbine

A very large scale wind turbine can be made as a circular large scale stator frame;the frame,which can reach some kilometers in diameter and some hundred meters in height,contains many circular sail trains.The stator frame can be made using a light-weight tubular design.Wind can almost freely blow through this frame.Train rails are fixed at the outer surface of the frame as horizontal rings.The distance between the rails of one ring can be made to be several meters.As a result,the number of the rings can be ten or more.Each rail ring supports one sail train that is moved with wind power around the frame.The energy of this movement is transformed to electric power and is transmitted to the base of the frame.This design can be realized in a very large scale,which is difficult to achieve using a traditional three-blade turbine.

An Experiment on Power Properties in a Small-Scaled Wind Turbine Generator

This study configures a simple wind tunnel using a blower for generating wind energy, which is equivalent to natural wind, and a test system that measures properties of power. Also, the mechanical and electrical power in a small-scaled wind turbine are empirically measured to analyze the relationship between the mechanical and electrical power.

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.

Providing Frequency Support of Hydro-Pumped Storage to Taiwan Power System with Wind Power Integration

The combination of wind and pumped storage is a useful method to compensate the fluctuation of wind power generation, which would exploit the abundant wind potential and increase wind power penetration. Taiwan Power Company (TPC) develops renewable energy actively in recent years. Moreover, TPC has started planning a high penetration wind power system and building offshore wind farms around the coast of Zhangbin, Yunlin and Penghu. The target of the offshore wind power installed capacity is up to 3 GW by 2025. However, the integration of the large scale of wind power would give huge challenges to the system operator because wind is randomly characterized. In this study, after high penetration wind power is integrated, the impacts of system frequency and the dispatch of conventional units will be discussed. Additionally, the hybrid system combing wind power with pumped-storage will be planning to reduce the effect of system frequency.

暂态电压稳定薄弱区域辨识的Louvain分区算法

针对大电网暂态电压稳定整体研究过于复杂的问题,提出一种暂态电压稳定薄弱区域辨识方法。首先,引入节点间电气距离计算模块度,运用Louvain算法对电网进行分区;然后,考虑线路负载率与线路开断对节点电压的影响,利用熵值法构建关键线路辨识指标筛选出关键线路,将关键线路三相短路故障作为预想故障集;最后,利用基于暂态电压稳定判据构建的节点暂态电压稳定评价指标,评价出暂态电压薄弱的区域。通过广东电网仿真结果验证所提方法的有效性。

Digitally Controlled Boost PFC Converters Operating with Large Scale Load Fluctuations

When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.

An optimal strategy for coordinating and dispatching “source-load” in power system based on multiple time scales

Due to the phenomenon of abandoning wind power and photo voltage(PV)power in the“Three Northern Areas”in China,this paper presents an optimal strategy for coordinating and dispatching“source-load”in power system based on multiple time scales.On the basis of the analysis of the uncertainty of wind power and PV power as well as the characteristics of load side resource dispatching,the optimal model of coordinating and dispatching“source-load”in power system based on multiple time scales is established.It can simultaneously and effectively dispatch conventional generators,wind plant,PV power station,pumped-storage power station and load side resources by optimally using three time scales:day-ahead,intra-day and real-time.According to the latest predicted information of wind power,PV power and load,the original generation schedule can be rolled and amended by using the corresponding time scale.The effectiveness of the model can be verified by a real system.The simulation results show that the proposed model can make full use of“source-load”resources to improve the ability to consume wind power and PV power of the grid-connected system.

Small Signal Stability Analysis with Penetration of Grid-connected Wind Farm of PMSG Type

The impacts of large-scale grid-connected wind farm on direct-driven permanent magnet synchronous generator(PMSG)type are discussed on the small signal stability performances of power systems.Firstly,a simplified practical model of wind farm of PMSG type is derived for analyzing small signal stability.The rotor-fluxoriented control strategy is applied to the modelling of PMSG.Secondly,the framework of small signal stability analysis incorporating wind farm of PMSG type is built.Finally,the different simulation scenarios based on the IEEE 3-generator-9-bus test system as benchmark are designed to conduct the eigenvalue analysis and to assess the impacts of wind farm of PMSG type on power system small signal stability.Some conclusions are drawn with simulation results.

基于Gabor变换的电网调度自动化设备运行状态监控技术

提出基于Gabor变换的电网调度自动化设备运行状态监控技术。该方法从电网调度自动化设备的大规模数据库技术和自动化电网调度技术入手,分别采集2项技术在电网调度自动化设备运行中存储和调度的状态信息,并将状态信息与Gabor变换结合,消除状态信息携带的干扰噪声,通过将优化后的状态信息输入以模糊神经网络与电网调度自动化设备健康评估体系为基础建立的设备运行状态监控模型中,实现电网调度自动化设备运行状态监控。实验结果表明,所提方法能够迅速监控电网调度自动化设备运行故障状态,监控功率与实际功率一致,监控精确度高。

Rolling Generation Dispatch Based on Ultra-short-term Wind Power Forecast

The power systems economic and safety operation considering large-scale wind power penetration are now facing great challenges, which are based on reliable power supply and predictable load demands in the past. A rolling generation dispatch model based on ultra-short-term wind power forecast was proposed. In generation dispatch process, the model rolling correct not only the conventional units power output but also the power from wind farm, simultaneously. Second order Markov chain model was utilized to modify wind power prediction error state (WPPES) and update forecast results of wind power over the remaining dispatch periods. The prime-dual affine scaling interior point method was used to solve the proposed model that taken into account the constraints of multi-periods power balance, unit output adjustment, up spinning reserve and down spinning reserve.

基于MQ-WaveNet的智慧新能源大规模风力发电智能控制

为了降低外部干扰,确保电力运行安全稳定,文章提出了基于多视界分位数和小波神经网络(MQ-WaveNet)的智慧新能源大规模风力发电智能控制方法。通过构建智慧新能源大规模风力发电机组模型,计算捕获的风能和叶尖速数值,调整发电机的速度,获得最佳功率系数。将气压、风向、风速等参数输入小波神经网络,根据层与层之间的权重,得到隐含层与输出层功率值;结合多视界分位数构成MQ-WaveNet模型,计算每一分位点的发电预测结果,明确风力发电的时序特征。利用李雅普诺夫函数估计,计算风力发电滑模面变换和控制矢量,在多分位点范围内达到滑模面,实现风力发电状态智能稳定控制。通过实验证明,文章提出的模型能够提高风力发电机组抗干扰能力,保证设备智能稳定运行。

无人机机载LiDAR在光伏发电项目大比例尺地形图测量中的应用

当前,光伏电站多建设在海拔高且高差大、植被多的地区,常规实时动态载波相位差分技术(RTK)测量方法效率较低,无人机倾斜摄影测量方法无法准确获取多植被区域的地面高程。基于此,提出一种在光伏发电项目大比例尺地形图测量中应用的无人机机载激光雷达(LiDAR)测量方法。首先从外业采集、内业数据处理两个方面介绍无人机机载LiDAR测量方法的技术流程,然后根据光伏发电项目应用实例数据对该测量方法的应用效果进行具体分析。研究结果表明:无人机机载LiDAR测量方法的植被穿透力强,可以快速获取植被下方高精度的地面点3D坐标,操作简单,且不需要布设大量像控点,外业采集的效率高;该测量方法的点云高程精度优于平面位置精度,可生产高精度数字高程模型(DEM)成果,直接提取等高线用于地形图成果绘制,内业数据处理的速度快。无人机机载LiDAR测量方法可以更好地满足在高山多植被地区的光伏发电项目建设的时间节点要求和精度要求,可以很好地应用于山区大高差的光伏发电项目大比例尺地形图测量作业。

Power Purchase Model of Provincial Grids Based on Diverse Energy Coordination Hedging Optimization

Under the background of energy conservation, the grid companies should give priority to consumptive hydropower, wind power and other clean electricity to fulfill their social responsibility and promote the carbon emission reduction in power industry. But under the current power purchase mode, grid companies must first perform the contract. This is extremely uneconomical and not environmentally friendly. Based on hedging theory, this paper proposes a power purchase optimization model using the strategy of “compression and compensation”. If outer price is lower than the contract price, the grid can compress contract power appropriately, leaving more space for purchasing electricity;if outer price is not attractive enough, the grid should timely improve contract proportion, compensating the deviations of contract caused by "compression". Based on the strategy of "compression and compensation", it can effectively reduce the abandoned wind and water, enhance the economic and social benefits of provincial power grid.