考虑风电不确定性的电网备用优化决策方法研究

基于风电并网的国内外研究的基础上,主要进行了风电不确定性的电网备用优化决策方法研究。利用风电不确定性、机组强迫停运率和负荷波动三方面建立系统的不确定性模型。以最小化备用成本为目标,并分别以解析法和mento-carlo模拟法求解系统的可靠性指标作为约束条件,构建确定系统所需的最优旋转备用容量的数学模型。对接有风电场的IEEE RTS96系统仿真,反映了相同的备用需求随风速变化的趋势,并比较得出模拟法得到的备用结果比解析法大。在此基础上,该方法还可以对风速预测偏差,风电渗透功率对系统所需旋转备用的影响进行进一步分析。     

考虑旋转备用约束的含风电场电力系统优化调度模型

文章建立电场电力系统优化调度模型,该模型考虑了风电功率预测误差的情况下,系统旋转备用容量满足负荷及风电波动的需求。模型中涉及火电机组、风电场的发电成本以及火电机组环境污染惩罚费用,并提出基于时变加速度的随机黑洞粒子群算法对模型进行求解,时变加速度增强了算法早期全局搜索能力,并保证迭代后期收敛到全局最优,同时黑洞原理避免了算法收敛早熟,陷入局部最优解。最后对含一个风电场的10机系统算例建模仿真,从而验证模型以及算法的合理性和有效性。     

考虑风功率预测误差相关性的旋转备用容量优化

文章研究了风电场间风功率预测误差相关性对系统备用容量选取的影响。首先,对不同风电场的风功率预测误差及其相互间的关联特性进行了研究,建立联合概率分布模型;其次,建立了考虑其相关性的旋转备用容量优化模型,模型兼顾经济性与可靠性,以火电系统燃料成本与停电损失之和最小为目标,约束条件着重考虑了系统切负荷与弃风概率均小于设定的置信度;最后,算例验证了模型的有效性,可为系统旋转备用容量的优化制定提供参考。     

考虑需求侧响应的风电并网系统旋转备用优化

随着新能源的快速发展,风电并网的规模逐渐扩大,由于风电出力的不确定性,风电消纳已成为新能源发展的主要挑战。考虑常规机组同时参与主辅市场,并融入需求侧资源可中断负荷及用电激励参与辅助服务市场,建立源荷协调的双层优化模型。上层模型以发电成本和弃风成本最小为优化目标,确定常规机组出力和风电计划出力;在上层优化结果基础上,下层针对常规机组调峰能力不足导致的弃风和失负荷情况,考虑用电激励和可中断负荷为备用资源,建立以发电侧旋转备用成本、用电激励成本、可中断负荷成本及失负荷损失和弃风损失的条件价值风险最小为目标的优化模型,得到旋转备用容量优化购买量。以修正的IEEE 6机30节点系统进行算例研究,仿真结果表明所建模型能有效提高系统经济性及风电消纳水平。     

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。     

含旋转备用的独立风光储系统控制与仿真

鉴于独立风光储系统配备一定容量的旋转备用的必要性,利用小型柴油发电机作为独立风光储系统的旋转备用,在PSCAD平台上建立了独立风光储系统的仿真模型,并提出将风力发电和光伏发电系统均采用恒功率(PQ)控制、蓄电池和超级电容器的混合储能系统作为主控制器采用恒压恒频(V/f)控制的控制策略,EMTDC仿真结果验证了将旋转备用控制引入独立风光储系统的正确性和有效性。     

含风电机组的随机生产模拟改进算法

等效电量频率法是针对大多数随机生产模拟忽略负荷的时序性而难以计算系统动态费用的问题而提出的随机生产模拟方法。将等效电量频率法忽略的除本台机组外的其他机组故障影响纳入机组启停次数的计算中,形成了改进的等效电量频率法。该方法在计算负荷频率曲线的时候考虑了应变分量f(i)3(x)的影响,并引起机组开机期望值、系统失负荷概率、缺电成本和启停费用的改变。通过对EPRI 36机组的随机生产模拟结果进行分析和比较,结果表明改进算法对系统可靠性和经济性均有改善。     

基于风速Weibull分布的电力系统备用容量优化模型

为了解决风电功率的随机波动和预测精度不高对风电并网的影响,引入风速Weibull概率分布函数和风功率概率分布函数,建立了基于风速概率分布的长期经济调度模型。该模型考虑长期调度和风电功率概率分布,在计算备用时不需考虑风电功率的时序性,这样使得模型得到了简化。最后通过算例仿真,讨论了该模型对系统备用容量和风电场成本的影响,同时验证了该模型的可行性。     

防止风电机组连锁脱网事故的动态无功备用需求分析

对风电机组连锁脱网事故的调查表明,双馈风电机组触发Crowbar保护进入低电压穿越区需要从电网吸取大量的无功,造成风电场电压进一步恶化。文章对大型风电场的无功需求和运行状况进行深入分析,推导出大型风电场的临界运行电压和无功备用容量计算公式,为风电场无功电压协调控制提供理论支撑。采用酒泉风电基地的实际算例进行了仿真分析,结果表明,风电场机组处于鼠笼异步运行状态时需要从电网吸收大量无功,同时风电场周边场站电压下降明显;而当动态无功备用容量达到临界动态无功备用容量及以上时,则能有效地改善风电场相关站点的电压分布。     

大规模风电并网的滚动备用分区分配策略

大规模风电的随机波动造成系统等值负荷的峰谷差拉大、断面潮流波动加剧,对发电调度的备用决策提出了更高要求。针对滚动调度环节,提出了大规模风电并网系统基于失负荷期望的备用风险决策模型,分析了失负荷期望与备用需求的关系。提出了系统失负荷期望为约束下的多目标备用分区分配决策模型,并采用基于模糊优化策略实现最小弃风、发电成本和分区期望失负荷率均衡等多目标的协调决策方法。由于备用容量与发电计划耦合约束的复杂性,采用改进粒子群算法对模型进行求解。最后,以IEEE 24节点系统为算例系统,对所提算法进行了验证。     

Spatial dependence in wind and optimal wind power allocation: A copula-based analysis

The investment decision on the placement of wind turbines is, neglecting legal formalities, mainly driven by the aim to maximize the expected annual energy production of single turbines. The result is a concentration of wind farms at locations with high average wind speed. While this strategy may be optimal for single investors maximizing their own return on investment, the resulting overall allocation of wind turbines may be unfavorable for energy suppliers and the economy because of large fluctuations in the overall wind power output. This paper investigates to what extent optimal allocation of wind farms in Germany can reduce these fluctuations. We analyze stochastic dependencies of wind speed for a large data set of German on- and offshore weather stations and find that these dependencies turn out to be highly nonlinear but constant over time. Using copula theory we determine the value at risk of energy production for given allocation sets of wind farms and derive optimal allocation plans. We find that the optimized allocation of wind farms may substantially stabilize the overall wind energy supply on daily as well as hourly frequency.     

Optimal offering and allocation policies for wind power in energy and reserve markets

Proliferation of wind power generation is increasingly making this power source an important asset in designs of energy and reserve markets. Intuitively, wind power producers will require the development of new offering strategies that maximize the expected profit in both energy and reserve markets while fulfilling the market rules and its operational limits. In this paper, we implement and exploit the controllability of the proportional control strategy. This strategy allows the splitting of potentially available wind power generation in energy and reserve markets. In addition, we take advantage of better forecast information from the different day‐ahead and balancing stages, allowing different shares of energy and reserve in both stages. Under these assumptions, different mathematical methods able to deal with the uncertain nature of wind power generation, namely, stochastic programming, with McCormick relaxation and piecewise linear decision rules are adapted and tested aiming to maximize the expected revenue for participating in both energy and reserve markets, while accounting for estimated balancing costs for failing to provide energy and reserve. A set of numerical examples, as well as a case study based on real data, allow the analysis and evaluation of the performance and behavior of such techniques. An important conclusion is that the use of the proposed approaches offers a degree of freedom in terms of minimizing balancing costs for the wind power producer strategically to participate in both energy and reserve markets. Copyright © 2017 John Wiley & Sons, Ltd.     

A framework to determine optimal offshore grid structures for wind power integration and power exchange

This paper presents a framework to find optimal offshore grid expansions using a transportation model of the power grid. The method extends the standard mixed‐integer linear programming approach to the solution of the transmission expansion planning problem to account for fluctuations in wind power generation and load; this makes the method especially suited to identify optimal transnational offshore high‐voltage direct current grid structures for the integration of large amounts of offshore wind power. The applicability of the method is demonstrated by a case study of the North Sea region. Copyright © 2011 John Wiley & Sons, Ltd.     

基于微网内节点功率优化配置的频率-电压调节方法

分布式电源出力以及节点负荷的不确定性,严重影响了孤网模式下微网系统的频率和电压。文章首先考虑发电机有功-频率特性,无功-电压特性以及负荷的频率电压特性,定义微网系统频率和节点电压对有功功率和无功功率的灵敏度;其次,将系统频率偏差和节点电压偏差进行归一化加权处理,得到优化目标函数;然后,以灵敏度较大节点为功率调节节点,采用粒子群优化算法对这些节点的有功功率和无功功率进行优化。在14节点的微网系统中对算法的验证结果表明,当孤网运行的微网系统频率和电压偏差需要调节时,文章所提出的算法通过优化微网节点的功率,能够使系统频率偏差和节点电压偏差减小,实现频率和节点电压的调节。     

电动汽车与风电协同入网的双层优化策略

文章提出了一种电动汽车(EV)与风电协同入网的双层优化模型.该模型上层以电动汽车与风电协同入网时负荷方差与充电站运营商购电成本最小为目标,得到电动汽车与风电联合的负荷指导曲线.模型下层以电动汽车和风电实际等效负荷与负荷指导曲线偏差最小为目标,进行实时负荷跟随.为保证电动汽车进行有序的充放电,提出了用户综合评价系数和放电...     

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。     

Providing power reserve for secondary grid frequency regulation of offshore wind farms through yaw control

The ability to significantly contribute to the frequency regulation and provide valuable ancillary services to the transmission system operator (TSO) is one of the present wind farm (WF) challenges, due to the limitations of wind speed forecasting and insufficient power reserve in certain operating conditions notably. In this work, the feasibility of WFs to participate in frequency restoration reserve (FRR) through yaw control is assessed. To this end, a distributed yaw optimization method is developed to evaluate the power gain achieved by yaw redirection based on wind turbine cooperation and compared with a greedy approach. The method relies on a static wake model whose parameters are estimated in a systematic way from simulation data generated with FAST.Farm. Through a case study based on a scaled version of the Belgian Mermaid offshore WF, it is demonstrated that the requirements of the TSO are fulfilled both in terms of response time and level of power reserve for most wind directions. The assessment is limited to wind speeds below the rated speed of the considered wind turbines.     

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。