考虑混搭风电机组的海上风电场集电线路拓扑动态优化方法

随着海上风电朝着深远海、大型化的方向发展,市场上风电机组的迭代速度加快,而海上风电场整体开发周期长,与风电机组的机型研发速度不相匹配,故在海上风电场的开发过程中可能会将不同型号的风电机组进行组合布机;但要如何在不同机型的搭配方式中,从经济性与可靠性的角度选择出最佳的拓扑结构进行连接,是混搭风电机组拓扑结构优化的主要难点之一。因此,构建考虑混搭风电机组的海上风电场集电线路拓扑结构动态优化方法,以改进K-means算法和改进Prim算法完成海上风电场的回路划分、路径设计;采用动态交叉优化策略完成拓扑中海缆交叉的处理,权衡每个拓扑方案的经济性与可靠性成本,进行最佳拓扑结构输出;最后通过不同混搭风电机组场景下的拓扑优化结果,验证该方法的有效性。     

电力系统潮流计算中双馈式风电场节点的处理方法

潮流计算是风电场接入系统设计的重要环节之一。准确的潮流计算结果对于建立风电场稳态模型是十分必要的。文章提出了不同控制方式下的双馈机组风电场节点在潮流计算中的处理方法以及潮流计算的具体步骤,给出了节点间的转化方法。运用PSASP进行仿真验证,证实了所提方法的可行性。     

综合利用SVG和双馈风电机组的风电场无功控制策略分析

针对风电场的无功功率平衡和电压稳定问题,提出了一种以风电场与电网交换无功功值为目标的控制策略。综合运用风电场安装的SVG无功补偿装置及双馈机组的无功调节能力来达到这一目标值。文章结合工程实例,通过对不同发电量下风电场的无功损耗和电压波动情况进行计算,提出利用风力发电机的无功功率可基本实现风电场的无功平衡。     

考虑风电机组位置差异的双馈风电场SSO特性及规律研究

首先建立基于多机等值的双馈风电场经串补并网系统的阻抗模型,并基于RLC阻抗稳定判据,分析不同位置机组控制参数和风速变化时对整个并网系统次同步振荡特性的影响,并通过仿真进行验证.结果表明,不同位置机组的控制参数及风速对整个系统次同步振荡特性的影响存在差异,且控制参数的差异会随风速的变化而变化.     

大型风电场尾流效应的耦合求解方法

针对大型风电场尾流评估问题,考虑大气边界层垂向动量输运和风电场内流动不均匀性,提出一种基于传统尾流模型和风电场边界层模型的耦合求解方法。采用Horns Rev风电场和青海锡铁山矿区风电场群实测数据对所提出的耦合方法进行验证,结果显示该方法可较为准确的评估大型风电场的场内、场间尾流效应,对大型风电场和集群化风电场开发具有重要理论和工程应用价值。     

基于RTDS的风电场等值建模与验证分析

针对风电场运行条件复杂、运行工况动态变化导致风电场输出功率的分散性问题,采用数理统计方法对风电场外特性进行稳态等值,考虑到大型风电场所处地形复杂、机群分布不规则带来的风速差异性问题,以风电场内长时间尺度实测风速数据作为特征变量,采用改进动态聚类算法进行机群划分,进而基于风电场参数对等值机模型的参数进行聚合辨识。基于RTDS实时数字建模及仿真试验分析结果表明,建立的风电场等值模型能够准确地反映风电场在不同风速及电网侧短路故障下的动态特性,可用于含双馈风电机组风电场接入电力系统稳定性分析。     

考虑尾流效应的风电场有功功率控制策略研究

随着大型风电场的快速发展,由于尾流效应造成的风电场能量损失成为重要的问题。本文考虑风电场内的尾流效应,提出了优化的有功功率和桨距角曲线以降低独立机组的能量损失,从而达到风电场的总有功功率提升的目的。同时,通过挖掘风电机组有功出力和尾流效应的关系,给出基于有功控制的尾流优化方法,建立了风电场有功出力优化模型。最后,基于某风电场的实际数据建立仿真模型来检验控制策略的有效性,并引入传统单机MPPT方案进行比对,结果证明提出的新型控制策略大大提高了整个风电场的有功功率,并且计算量小,优化方法简单,具有一定的工程应用价值。     

基于偏航尾流模型的风电场功率协同优化研究

为减小风电场尾流效应的影响,提升风电场整体发电量,提出一种基于偏航尾流模型的风电场功率协同优化方法。首先建立风电场偏航尾流模型,该模型包括用于计算单机组尾流速度分布的Jensen-Gaussian尾流模型、尾流偏转模型及多机组尾流叠加模型,对各机组风轮前来流风速进行求解;再根据来流风速计算风电场输出功率,并以风电场整体输出功率最大为优化目标,利用拟牛顿算法协同优化各机组轴向诱导因子和偏航角度。以4行4列方形布置的16台NREL-5 MW风电机组为对象进行仿真研究。结果表明,所提出的基于偏航尾流模型的风电场功率协同优化方法能显著提升风电场整体输出功率。     

双馈风电场有功频率分层控制

风电场有功频率控制是风电场接入电网运行的关键技术。在分析双馈风力发电机组减载运行控制策略及超速法下双馈风力发电机组的减载运行调节能力的基础上,提出了提高双馈风电场的有功调节能力及接入电网后系统频率稳定性的有功频率分层控制策略。该策略根据不同风速区风电机组的减载运行调节能力差异,设计了风电场层分配策略及风电机组层控制策略,在满足有功控制要求的前提下,尽可能提高风电场对电力系统暂态频率稳定的支持。仿真结果表明,该控制策略在系统稳定运行时尽可能存储转子动能,当出现功率扰动后,能够通过快速释放转子存储的动能响应系统频率变化,从而提高了双馈风电场接入电网后的系统频率稳定性。     

基于多尾流模型的大型海上风电场扩容试验研究

目的  文章旨在研究大型海上风电场的最佳规划容量设置。 方法  针对某1 GW容量的单个规划场址,利用3种不同单机容量机型与3种海上风电场尾流模型,结合海上风资源图谱开展同场址逐步扩容至2 GW的一系列数值试验,并对全场发电量、尾流影响与边际效应进行分析。 结果  结果显示,随着机型的单机容量增大,扩容过程中全场实际发电量增幅越高,尾流损失增长越慢,兼顾机组安全性与投入产出比的有效扩容区间越大;但尾流模型选择可能影响有效扩容区间评估结果。 结论  文章研究表明,在满足现有用海指标、风电机组安全性与工程经济性等多重约束下,单个场址的最佳规划容量可以略高于现有基准值,在今后海上风电千万千瓦级基地规划中,应科学细分并合理设置单个场址的规划容量。     

基于ADMM的风场两级分布式无功优化方法

由于风机的无功耗变,电网电压稳定性随着风力渗透的增加而降低.针对风电场接入的配电网系统无功优化调度问题,本文提出了一种基于ADMM算法的两级无功优化调度方法.与现有的无功优化控制方法相比,该方法采用两阶段优化结构实现分布式无功优化调度.此外,在分区概念下,不需要一致性协议来解决优化问题.该方法在控制设计中也考虑了各个风...     

Development and simulation of dynamic control strategies for wind farms

The authors show that: (a) with reliable prediction of low variance in the wind velocity, modern wind farms have the wherewithal to produce regulated power in the next hour; (b) when the conditions for producing regulated power are not predicted, the wind farms may opt to use the tracking mode which tracks the slowly time-varying, non-turbulent component of wind power and (c) the proposed control system has the capability to divert some of the wind farm power to implement dynamic performance enhancement strategies, for system damping. The capabilities are demonstrated by simulations of a wind farm made up of 24 windturbine generators using one-hour-long wind velocity data.     

Aggregated dynamic model for wind farms with doubly fed induction generator wind turbines

As a result of increasing wind farms penetration in power systems, the wind farms begin to influence power system, and thus the modelling of wind farms has become an interesting research topic. Nowadays, doubly fed induction generator based on wind turbine is the most widely used technology for wind farms due to its main advantages such as high-energy efficiency and controllability, and improved power quality. When the impact of a wind farm on power systems is studied, the behavior of the wind farm at the point common coupling to grid can be represented by an equivalent model derived from the aggregation of wind turbines into an equivalent wind turbine, instead of the complete model including the modelling of all the wind turbines. In this paper, a new equivalent model of wind farms with doubly fed induction generator wind turbines is proposed to represent the collective response of the wind farm by one single equivalent wind turbine, even although the aggregated wind turbines operate receiving different incoming winds. The effectiveness of the equivalent model to represent the collective response of the wind farm is demonstrated by comparing the simulation results of equivalent and complete models both during normal operation and grid disturbances.     

一种多维风电场相关性的优化建模方法

随着风电并网规模的不断扩大,出现了同一区域有多个风电场接入的情况。由于区域内不同风电场的出力具有较强的地域相关性,因此,构建一个能准确描述多风电场出力相关性的模型,对含大规模风电场电力系统的运行具有重大意义。文章基于Pair Copula理论构建了7维风电功率的相关性模型,并选取澳大利亚多个风电场出力样本进行实例分析。分析表明,Pair Copula模型能较好地描述高维相关性,但随着维度增加,模型精度有所下降。为此,文章利用智能优化算法(粒子进化算法),首次提出了一种基于Pair Copula模型参数优化的多风电场出力相关性优化建模方法。通过仿真分析表明,与传统方法相比,该方法大大提高了模型精度,验证了所提方法的有效性和优越性,对含多风电场电力系统的运行具有重要参考价值。     

Power quality assessment of grid-connected wind farms considering regulations in turkey

This paper presents measurement system and detailed analysis of power quality at the substation of two different wind farm sites which are of low and high power rate. Measurement system has been designed using a data acquisition board (DAQ), Labview software, Matlab programming and a portable PC. The system has been installed at medium voltage level at substation of both wind farms. The real measurement results at substations are compared to current regulations in Turkey.     

考虑风电消纳能力的含风电场电力系统多目标优化调度研究

针对含风电场的电力系统调度中存在的风电消纳问题,提出一种基于第二代非劣支配排序遗传算法(Non-dominated Sorting Genetic Algorithm II,NSGA-II)的多目标优化调度方法。为使电力系统在消纳尽可能多的风电同时,兼顾经济性、安全性和环保性,分别以风电消纳、发电成本和污染物排放量为目标建立了含风电场电力系统双目标及三目标调度模型,采用NSGA-II进行优化求解,并详细分析了不同目标组合策略下电力负荷、机组组合和优化目标对风电消纳的影响程度,同时引入伪权向量法为决策者提供非劣解信息,辅助决策者完成优化调度。分析结果表明,该方法有助于评估机组组合、目标组合等因素对电力系统优化调度的影响程度,对合理提高含风电场电力系统的风电消纳能力有一定的指导意义。     

海上风电场MMC-MTDC下垂控制特性的模型预测控制技术

基于模块化多电平换流器(Modular Multilevel Converter,MMC)的多端直流输电(Multi-Terminal HVDC,MTDC)系统被应用于海上风电场并网,其控制策略对于电力系统的稳定性有着重大的影响。文章分析了MMC典型控制系统,结合海上风电场MMC-MTDC并网系统的下垂控制策略,建立MMC及其控制系统的简化状态空间方程;提出了一种基于模型预测控制(Model Predictive Control,MPC)的MMC控制方案,对d轴分量的有功功率和直流电压采用模型预测控制。通过PSCAD中基于4端MMC-MTDC的海上风电并网系统的仿真测试,验证了所提方法的可行性和有效性。     

Spanish method of visual impact evaluation in wind farms

The present Spanish laws on the procedure to evaluate the environmental impact of wind farms are ambiguous, especially those pertaining to visual impact. There is no specific national law but only regional laws. The main targets of these laws are the conservation of the environment (protected animals and plants), and the noise generated. The focus of this paper, the visual impact, is not taken into account in a direct way in these laws.This work develops a methodology to predict, before its construction, the visual impact that a wind farm can have. This could be used as a consulting tool to analyze and evaluate wind projects, both government-run and private.The developed methodology is quick, concise and clear.     

Coordinated generation and transmission expansion planning in deregulated electricity market considering wind farms

This paper deals with a coordinated generation expansion planning (GEP)–transmission expansion planning (TEP) in competitive electricity market. In the proposed method, GEP and TEP are performed at the same time, with consideration of wind farm uncertainty. The uncertainty is modeled by normal probability distribution function (PDF) and Monte-Carlo simulation (MCS) is used to include the uncertainty into the problem. The planning is managed for two master and slave levels. At slave level, all generation company (GENCO) and transmission company (TRANSCO) maximize their profit and then at master level, the system constraints are checked by independent system operator (ISO). In other words, the proposed planning aims at maximizing the expected profit of all GENCOs and TRANSCOs, while considering security and reliability constraints such as reserve margin and loss of load expectation (LOLE). The proposed problem is a constrained, nonlinear, mixed-integer optimization programming and solved by using particle swarm optimization (PSO) method. Simulation results verify the effectiveness and validity of the proposed planning for maximizing GENCOs and TRANSCOs profit in the presence of wind farm uncertainty under electricity market.     

Global experience curves for wind farms

In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline.