提出一种适用于大型风电场的自适应频率响应控制方法,使风电场能参与电力系统频率调节.低频事件发生后,每台风电机组的下垂控制系数均根据其本地实时风速和功率裕度呈反比例自适应调节.高频事件发生后,每台风电机组的高频响应控制增益随其本地实时风速自适应调节.由此,风电场频率响应支撑功率可自适应的在多台风速各异的风电机组之间实现合理分配.该方法充分考虑频率响应过程中多台风电机组之间的风速差异,不仅可提高风电场整体的频率响应能力,而且可确保频率响应过程中每台风电机组的稳定运行.在Matlab环境下进行相关仿真实验,结果验证了所提控制策略的有效性.

混流式水轮机的尾水管压力脉动作用力对机组动态特性有直接影响,该作用力的最主要特征指标为频率及幅值.传统公式法不能反映出主频与负荷效应的关系,因此文中着眼于对全负荷段尾水管压力脉动频率计算方法的研究,并且结合其对机组稳定性运行的影响效果进行了深入探讨.从尾水管涡带产生的机理出发,推导全负荷段尾水管压力脉动频率的计算公式,并结合在2种不同补气条件下的实测数据,对涡带特性进行深入研究,阐述了涡带对机组运行品质的影响效果.对比在2种补气工况时的实测结果,发现在压力脉动作用较为明显的负荷区间内,全负荷段压力脉动计算方法的计算结果与试验结果贴合程度较高,说明该方法可以较为准确地反映实际运行特性.补气能减少涡带的主要原理在于其能削弱脉动的相对幅值,而对脉动频率无大的改变,这对提升机组稳定性运行的效果有着直接的影响.研究结果对于分析水电机组动态特性有着积极的意义.

针对光伏电站一次调频与 自动发电控制(AGC)存在不协调、相互干扰的问题,提出了一种能够在光伏电站应用的多主站协调控制方法,通过一次调频测控系统与AGC系统协调实现2个控制主站对光伏电站逆变器的功率控制.通过在光伏电站改造应用,完成了改造后的各项频率扰动试验和协调性试验.试验研究表明改造后光伏电站能够参与系统一次调频,并且多项指标能够超过常规的火电和水电的调节性能.

This paper presents an adaptive over-frequency response control scheme for the large-scale wind farm, which enables wind farm to participate the grid frequency regulation. The main advantage of this scheme is that, by adjusting the over-frequency control gain of each wind generator according to its local wind speed, this scheme takes into account the wind speed difference among wind generators. Specifically, the over-frequency control gain of each wind generator is linear with its local wind speed. As a result, not only the wind farm frequency regulation performance is improved, but also the wind generator stability is ensured. Simulation results on the data collected from a real wind farm validate the effects of the proposed control scheme.

For distributed generation system, the grid is no longer an ideal grid, but a weak grid which contains internal impedance. The grid impedance has a serious impact on system stability and power quality for PV grid-connected system. In this paper, the small-signal model and state equation of the grid connected system are established under weak-grid, the influence of grid impedance on system eigenvalue is analyzed. The sensitivity of each characteristic mode to the state variable is obtained by using the participation factor analysis, and the influence of each key parameter on the small disturbance stability of the system is analyzed. Lastly, the stability regions of single-system parameters, double-system parameters and multi-system parameters under different grid impedance are discussed. The analysis results show that the small disturbance stability of the PV system can be improved by adjusting the control parameters reasonably, which provides a theoretical basis for the optimal design of the controller.

Traditional wind speed forecast usually regards wind farm as a point to make forecast, but in a wind farm, wind speed of wind turbines in different geographical locations is not the same. For many wind turbines with wide geographical distribution in a wind farm, this paper gives a forecast method based on convolutional neural network (CNN) to forecast the wind speed at each wind turbine location. In this method, the wind speed and direction characteristics of all wind turbines at different geographical locations are input into the CNN network as variables, and local low-dimensional features of the original data are mapped to high-dimensional features through convolution operation of CNN, thereby realizing the wind speed forecast. The main advantage of this method is that by automatically studying the informative spatial correlation of wind speed, rather than artificial extracting , multi-task forecasts(MTF)are made and the wind speed forecast at different wind turbines locations is more informative and accurate.

针对滑动轴承中润滑油温度的不稳定变化而引起的转子系统振动问题,从油膜润滑的雷诺方程出发,在Gumbel油膜边界条件假设下,推导出短轴承的非线性油膜力的计算公式.将润滑油温度变化时黏度的变化考虑在内,采用四阶Runge-Kutta法求解系统微分方程得到转子-轴承系统运动的时域图、轴心轨迹图、Poincaré图、频谱图、瀑布图和分岔图,分析滑动轴承-转子系统在润滑油温度变化下的动态响应.结果 表明,使用不同润滑油时,温黏系数较大的润滑油对转子二阶临界转速附近的拟周期和混沌运动有更好的抑制作用;润滑油温度的升高有利于转子系统在低转速范围运行的稳定性,但在二阶临界转速附近,发生油膜涡动和油膜振荡所对应的转速区域会有所延长,不利于转子-轴承系统的运行.

目前大量并网的风电机组按最大功率跟踪曲线运行,其功率不能响应电网频率的变化,不具备一次调频功能,这将严重影响电网的安全稳定运行.在分析风电场运行状况基础上,提出在现有风电场机组中加入虚拟惯性控制策略,以提高风电机组输出功率快速响应电网频率变化的能力;通过在风电场集中引入下垂控制策略,获得风电场一次调频总功率,再经过风电场能量管理平台分发给各台风电机组,实现风电场一次调频功能.现场试验结果表明,风电场机组能够像常规发电机组一样进行电网一次调频,其一次调频响应有功功率的速度优于水电机组指标规定的要求.

This paper presents an adaptive frequency response control scheme for the large scale wind farm, which enables wind farm to participate the grid frequency regulation. The main advantage of this scheme is that, by adjusting the droop coefficient of each wind generator in response to its local wind speed, this scheme takes into account the wind speed difference among wind generators. Specifically, the droop coefficient of each wind generator is dynamically adjusted inversely proportionally to the local power margin, which is computed using the local wind speed. This way, the wind farm frequency support power is distributed among multiple wind generators in an adaptive and reasonable fashion. As a result, not only the wind farm frequency support performance is improved, but also the wind generator stability is ensured. Simulation results on the data collected from a real wind farm validate the effects of the proposed control scheme.

提出了一种基于全场控制的风电场一次调频控制方式以及自动发电控制(AGC)与一次调频协调控制方法.通过加装一套一次调频测控系统实现了风电场全场一次调频功能,风力发电机组本身的负荷调节采用转速控制与桨距角控制方式;完成了风电场一次调频的工程化应用,并进行了阶跃扰动试验、模拟电网频率扰动试验及挂网测试.试验结果表明采用该方法改造后的风电场一次调频性能良好.

频率是衡量电能质量的重要指标之一,大规模风电并网对电网的频率稳定提出了更大的挑战.为了深入挖掘风电机组的调频潜力,提出了基于惯性和变桨协调的一次调频控制策略.一方面,在常规控制环节中增加虚拟惯性控制和下垂控制;另一方面,通过变桨距控制使风电机组实现减载运行,从而保留部分有功功率作为备用.仿真结果表明,当频率发生变化后,机组能够快速有效地做出响应,从而为系统频率恢复提供支撑.

提出一个二维圆弧翼型的力学模型,以非定常伯努利方程为基础,在不考虑来流所引起环量的情况下,计算得到叶片所受到的法向力、升力和阻力的表达式.在计算过程中,采用儒可夫斯基保角变换法将圆弧翼型上的位移、速度等转换为极坐标形式,简化计算分析过程.在此基础上,通过给定攻角随时间变化的函数,分析得到叶片在连续时间域的非定常受力变化曲线,并探讨不同拱高圆弧翼型受力的变化规律,为研究更为复杂翼型叶片的气动性能奠定基础.

According to the requirements for the power system simulation,this paper presents an in-depth study of the the module structure and working principles of the AGC load adjusting of the hydropower station monitoring system,establishing and improving a model which can correctly reflect the hydroelectric power station control system,including standalone AGC load adjusting parts,turbines and water intake system and the speed governor.The model can simulate the primary frequency modulation,and single unit AGC load increase and decrease process.In addition,to verify the model An Kang hydropower plant is simulated.

With the increased concern about energy shortage and advances in technology, wind power comes to become an important issue in various countries. The wind turbine working condition is relatively complex than general mechanical condition. In variable working condition, wind turbine and system is easy to be made plastic deformation and generate additional structure stress by inertia force function. The wind turbine monitoring system is able to give the equipment running status report for forecasting warning before the damage of wind generator parts (gear, axle, bearing), to ensure condition monitoring and defects alarming. In this paper, a wind turbine generator monitoring and analysis system is developed. The system structure, function and arrangement of measuring points are discussed in detail. The simulation shows that operational status of the wind turbine generators can be judged the system the, displaying a large number of real-time data, meanwhile can pre-alarm and other functions with the SQL into the database. (4 pages)

The comprehensive performance testing for operating states of bulb tubular turbine generating units of certain power station is carried out,evaluation is conducted according to the relevant technology standards,vibration areas of the units is divided,improvement measure is proposed for existent problems of the units,and scientific basis is provided for maintenance and operation of the units.

In the light of low precision of the turbine model used in power system simulation calculation,this paper analyzes the turbine and its pressurized water diversion system,simplifies and improves the model of the turbine and its pressurized water diversion system based on the power system simulation calculation,proposes the suggestions to select corresponding water hammer model according to the characteristic of the water diversion system.Simulation instance shows that improved model enhances simulation precision of the model,and can be used in the system simulation calculation.

According to the characteristics of the units and regulating system of the Laxiwa Hydropower Station,and in consideration of the power counter-adjustment in hydro-units primary frequency modulation process,the primary frequency modulation parameters are optimized according to the primary frequency modulation technology requirements of electric power dispatching institution. The poor matching between primary frequency modulation and AGC (secondary frequency modulation) is improved and optimized; thus,both primary frequency modulation and AGC can play their normal functions.

Primary frequency regulation is one of the ways to ensure the stability of power system.At present,many hydropower plants use primary frequency regulation according to orders.This paper points the introduction of primary frequency regulation integral power,using the Northwest Power Grid frequency data for modeling and simulating in Gongboxia Hydropower Station NO.4 unit.It analyzed the effect of integral power by the key parameters of primary frequency regulation to frequency dead zone and opening dead zone.It can provide the references for hydropower plants about how to obtain the maximum benefit with primary frequency regulation using.

The mathematical model of regulation system is set up through the analysis of system structure,control rule and regulation characteristics in No.4 hydroelectric generating set,Gongboxia Hydropower Station.Satisfactory effect has been obtained through the calibration of original parameter by nonlinear least square method which in Matlab parameter identification tool box.Nonlinear model of Hydrogenerator and pressure diversion system are improved to make simulation fitness and parameter identification result improve greatly.

Data authenticity and reliability of hydraulic turbine control system tests are important bases for the correct assessment of safe operation of a hydro-generating unit. A research is done on the use of adaptive weighted point of post-filtering and adaptive point weighted smoothing filter in the middle of the trial data processing,and the use of data before and after processing for parameter identification in the Gongboxia 4th unit Electro-hydraulic servo system. Research result shows that the method can effectively deal with turbine control system test data.