前端调速型风电机组动力学建模与运行特性研究

基于先进的机械调速与伺服控制技术,提出了一种带有发电机前端无极调速器的混合传动风电机组方案,以实现变速恒频。利用集中质量与拉格朗日方法,建立该机组传动系统动力学模型。并利用动力学方程建立1.5 MW前端调速型风电机组的Simulink仿真,实现对机组调速精度、功率消耗、电流谐波与低电压穿越能力等运行特性的深入研究。结果表明:在不同的风速条件下,所提机组不仅可以在调速功率消耗较小的情况下输出恒频电能(占比小于输出功率的15.25%),还可以有效抑制电流谐波污染,改善机组低电压穿越能力。理论分析与仿真研究验证了该机组的实用性和优越性。     

电压型虚拟同步发电机控制策略下的双馈风电机组阻抗及次同步振荡特性

针对双馈风电机组（doubly-fed induction generators,DFIG）经串补送出系统存在次同步振荡（sub-synchronous oscillation,SSO）的问题,以电压型虚拟同步发电机（virtual synchronous generator,VSG）控制策略下的DFIG为研究对象,首先基于三相静止坐标系建立了其阻抗模型,推导了机组正、负序阻抗解析式;其次搭建了PSCAD/EMTDC模型,对理论推导阻抗特性和频率扫描结果进行了对比验证;最后基于奈奎斯特稳定判据定量分析了VSG控制策略下的DFIG经串补送出系统SSO特性,通过仿真验证了所建立模型和稳定性分析结论的正确性。研究结果为SSO的抑制提供了参考。     

分析风电机组低电压穿越能力影响因素

随着我国发展理念的转变,我国的电力部门在电力生产的过程中加强了对于风电资源的开展以及利用。随着风力发电规模的进一步扩大,如何实现风力发电并网稳定性的提升,成为电力部门亟待解决的问题。本文基于此,分析探讨了风电机组低电压穿越能力影响因素。     

变浆距对风机性能改善的研究

<正>鼠笼异步发电机(Squirrel Cage Induction Generator,SCIG)结构简单,便于维护,在风电场得到广泛应用。风力发电装机总容量在电力需求中比例逐步上升,而风电又是一种不可控能源,具有间歇性和随机性,风电机组并网运行,会消耗一定的无功功率,这会对对电网的电压质量产生负面影响。特别是发生电网发生短路故障时,电压急剧下降,风电机组无法向系统输送能量,且需要大量的无功功率来完成电压的恢复。通常情况下,电网在发生短路故障下,风电机组出于保护自身的需要,将与     

风电叶片防护涂层材料的研究进展

为实现风电叶片长期稳定运转,需要在叶片上涂装防护涂层使得叶片具备优良的耐候、耐磨、防污等性能。文中介绍了各种合成高分子树脂材料在风电叶片保护领域的研究进展,包括应用最普遍、性能全面的聚氨酯,耐候性极佳、表面能较低的氟聚合物以及粘接性好、附着能力强的丙烯酸树脂等。这些聚合物以单一组分或几种材料复合的形式制备成单层或多层的防护涂层,以期使得叶片涂料具备优异的防护性能。     

张家口风电基地蓄势待发

张家口坝上地区风能资源丰富，风能蕴藏量为1700万kW左右，且该地区靠近区域电力负荷中心，具备规模化开发风电的条件。按照“统一规划、分期实施、讲求效益、保护资源”的原则，国家规划在张家口坝上地区，择优选择部分地点作为大型风电场场址，建设国家级百万千瓦风电示范基地，到2010年完成风电装机100万kw以上。     

火力发电厂发电机定子非常规吊装方案探讨

火力发电厂的发电机定子是电厂施工中最重的部件。也是施工工艺难度较大的部件之一。现在火力发电厂发电机定子安装中常采用的工艺是液压提升装置进行吊装。这种办法几乎涵盖了定子吊装方案的90%以上。在施工场地具备的情况下也有用大型起重机械直接吊装就位的。本文主要介绍在机组扩建,场地狭小的条件下从发电机卸车至发电机定子吊装完成的一种非常规方案。     

风电机组防雷问题初探

首先介绍风力发电机叶片的结构,从构筑物的角度进行考虑,风力发电机可以进行防雷分区,按照这种分区方式可以确定风机的不同位置需要采取怎样的防护措施。按照危险程度进行划分:处于LPZ0区的部分包括叶片、风速仪;LPZ1区包括:风机(机舱)罩、塔桶电缆;LPZ2区包括:变浆柜、控制柜等。其次,结合风电机组防雷的研究成果,对风电机组叶片、机舱、电控系统(包括配电变压器、电源、信号电路、通讯接口)的防雷措施和接地技术进行较初步的阐述。     

2015年海上风电装机规模预计可达500万kW

据报道,在“2011上海国际海上风电及风电产业链大会暨展览会”上,水电水利规划设计总院副总工程师易跃春介绍,自2007年起步以来,我国已建成海上风电装机14．25万kW,初步具备了海上风电设计、施工及设备制造的能力,预计到2015年,我国海上风电装机规模将达到500万kW,2020年将达到3000万kW。     

基于新一代信息技术的风电机组检验检测技术

本文首先介绍我国风电产业标准体系及关键检验检测认证项目,讨论检验检测项目的条件限制及安全隐患,接着分析新一代信息技术(5G、人工智能、大数据、云计算)在上述检验检测条件下的突出优势.研究发现新一代信息技术的应用有助于提高风电行业整体的检验检测能力和效率.通过典型风电检验检测项目的试验应用,验证了新技术应用的可行性.     

Wind-driven stand-alone DFIG with battery and pumped hydro storage system

A wind-driven doubly fed induction generator (DFIG) along with the battery and pumped hydro storage plant (PHSP) has been devised for supplying isolated loads. PHSP-based storage system is economical and viable for the MW level wind-turbine system. The proposed scheme employs a squirrel-cage induction machine (SCIM) coupled with reversible pump turbine for PHSP. The battery storage is also included in this system to cope up with the intermittent nature of wind and fast-changing load. A simple control strategy has been implemented for maintaining the set values of voltage magnitude and frequency at the stator terminals of DFIG, which serve as a virtual grid for connecting ac loads and SCIM. Based on the availability of power in the wind, PHSP and battery, various operating modes of the proposed system have been clearly identified for supplying the isolated loads. These operating modes are clearly demonstrated through the analysis developed for this purpose and validated through experimental results. The salient features of the proposed system over the existing stand-alone wind-driven generators are (i) structural simplicity, i.e., employing only one power electronic converter, (ii) wide speed operation of wind-driven DFIG, (iii) reduced battery capacity, (iv) high energy storage using PHSP and (v) availability of continuous power to the isolated loads.     

VSC-HVDC稳定控制研究

基于电压源换流器（voltage-source converter,VSC）的高压直流输电系统（high voltage direct current,HVDC）拥有良好的有功无功功率控制能力以及更适合构成多端输电系统的优势,目前被认为是极具潜力的输电方式。柔性直流输电系统的控制及稳定性是影响输电系统运行安全和性能的重要因素。针对柔性直流输电系统的研究,首先概述了两端柔性直流输电系统的拓扑及其解耦控制和附加控制方式,然后从基本的两端拓扑结构延伸到多端输电系统拓扑和混合输电系统拓扑,着重分析了多端系统的下垂控制、故障穿越能力和混合直流输电系统的控制,接着又讨论了风电接入之下的柔性直流输电系统的稳定性及控制,可为今后相关研究提供参考。     

Small signal stability analysis and optimal control of a wind turbine with doubly fed induction generator

A novel method using particle swarm optimisation (PSO) is proposed for optimising parameters of controllers of a wind turbine (WT) with doubly fed induction generator (DFIG). The PSO algorithm is employed in the proposed parameter tuning method to search for the optimal parameters of controllers and achieve the optimal coordinated control of multiple controllers of WT system. The implementation of the algorithm for optimising the controllers' parameters is described in detail. In the analysis, the generic dynamic model of WT with DFIG and its associated controllers is presented, and the small signal stability model is derived; based on this, an eigenvalue-based objective function is utilised in the PSO-based optimisation algorithm to optimise the controllers' parameters. With the optimised controller parameters, the system stability is improved under both small and large disturbances. Furthermore, the fault ride-through capability of the WT with DFIG can be improved using the optimised controller. Simulations are performed to illustrate the control performance.     

Three-phase doubly fed induction generators: an overview

Adjustable speed induction generators, especially the doubly fed induction generators (DFIG), are becoming increasingly popular due to their various advantages over fixed speed generator systems. A DFIG in a wind turbine has the ability to generate maximum power with varying rotational speed, ability to control active and reactive power by the integration of electronic power converters such as the back-to-back converter, low rotor power rating resulting in low cost converter components, and so on. This study presents an extensive literature survey over past 25 years on the different aspects of DFIG.     

被动湍流控制圆柱驰振能量收集的等效电路研究

为更好的预测驰振压电能量收获机的性能,首先建立了等效电路仿真模型(ECM)并通过实验验证,最大误差不超过10%。采用该方法分析了被动湍流控制(PTC)下圆柱驰振压电能量收集的仿真模型,且该方法可将驰振能量转化系统的质量-弹簧-阻尼(M-C-K)控制方程中各参数用等效电路的电子元件来表示,从而可以分析过往仿真手段所不能解决的直流电路耦合问题。其次,从能量收集效率角度分析了交流-直流等效电路中临界风速(Ucr)随外接载荷的变化规律,及输出电压与功率随不同风速和外界载荷的变化规律。结果表明,交流电路中Ucr随载荷的增大先增大后减小,直流电路中Ucr随载荷的增大逐渐减小。当风速达到Ucr的最大值时,驰振在任一电阻下均会发生。U≥Ucr时,驰振出现锁定现象,输出电压和功率均随着风速的增大而增大。当风速过大时,增长率有减小趋势。输出电压均随着电阻的增大而增大,功率随电阻的增大先增大后减小。相比于交流电路,直流电路的最佳负载由1.1 MΩ提高到2.0 MΩ,同时功率峰值从0.08 mW降低到0.04 mW。     

The New Developed Components Tests for 1 MJ Capacitor Power Supply System in Wuhan High Magnetic Field Facility

A new 1 MJ, 25 kV, 40 kA pulsed capacitor power supply system for the Wuhan High Magnetic Field Facility (WHMFF) has been achieved. The desire for 70 or higher tesla magnetic field to support a lot of scientific researches based on it is just now beginning to be realized. The system consists of charger, capacitor bank, polarity changing switches, protective inductor, thyristor switch, crowbar, dump circuit and so on. In this paper, a series of tests for the new developed components such as high energy pulsed capacitor with 160 μF/25 kV/10 kA/10 ms/30% voltage reversal, thyristor switch (25 kV, 40 kA, 10 ms), polarity changing switch and ZnO linearly resistor disc for crowbar are introduced. The results show that all of new components are good or better than the old 1 MJ power supply system.     

Fractional-Order Control of a Wind Turbine Using Manta Ray Foraging Optimization

In this research paper, an improved strategy to enhance the performance of the DC-link voltage loop regulation in a Doubly Fed Induction Generator (DFIG) based wind energy system has been proposed. The proposed strategy used the robust Fractional-Order (FO) Proportional-Integral (PI) control technique. The FOPI control contains a non-integer order which is preferred over the integer-order control owing to its benefits. It offers extra flexibility in design and demonstrates superior outcomes such as high robustness and effectiveness. The optimal gains of the FOPI controller have been determined using a recent Manta Ray Foraging Optimization (MRFO) algorithm. During the optimization process, the FOPI controller’s parameters are assigned to be the decision variables whereas the objective function is the error racking that to be minimized. To prove the superiority of the MRFO algorithm, an empirical comparison study with the homologous particle swarm optimization and genetic algorithm is achieved. The obtained results proved the superiority of the introduced strategy in tracking and control performances against various conditions such as voltage dips and wind speed variation.     

Influence of the grid parameters during under voltage ride through (UVRT) testing

Under-voltage ride through (UVRT) tests can be carried out on system test benches, most of them are equipped with a converter based grid simulator. This paper describes the control of the artificial grid impedance at the 4 MW test bench at CWD. Validation measurements with the commercial wind turbine E‑115 E2 show that the virtual impedance specification is sufficient to perform UVRT tests with different grid parameters. Comparative measurements between the voltage divider based FRT Container and the grid simulator with deliberately different grid parameters show a different behavior of the research wind turbine FVA nacelle. Therefore, it is recommended to perform UVRT tests on the test bench with predefined grid parameters.

     

Graphical determination of network limits for wind power integration

A graphical method is presented for determining the capability of individual system nodes to accommodate wind power generation. The method is based upon constructing a capability chart for each node at which a wind farm is to be connected. The capability chart defines the domain of allowable power injections at the candidate node, subject to constraints imposed by voltage limits, voltage stability and equipment capability limits being satisfied. The chart is first derived for a two-bus model, before being extended to a multi-node power system. The graphical method is employed to derive the chart for a two-node system, as well as its application to a multi-node power system, considering the IEEE 30-bus test system as a case study. Although the proposed method is derived with the intention of determining the wind farm capacity to be connected at a specific node, it can be used for the analysis of a PQ bus loading as well as generation.