含风电的多域互联电力系统负荷频率控制方法

为确保风机参与调整系统负荷频率,建立了三区域含风力发电的互联电力系统负荷频率控制模型;同时,为抑制整个系统内部参数的变化、风能波动及负荷扰动所造成的负荷频率波动,又设计出一个分散的滑模控制器并用于仿真分析,当整个系统在进入滑动模态后,对外界的参数变化具有时不变性。仿真结果表明,所设计的滑模控制器比传统的控制器响应更快、超调量小,有效抑制了负荷频率波动,且当考虑发电机变化率约束条件时,所设计的滑模控制器仍能有效控制系统稳定。     

Optimizing 100%‐renewable grids through shifting residential water‐heater load

A low‐carbon electricity supply for Australia was simulated, and the installed capacity of the electrical grid was optimized by shifting the electricity demand of residential electric water heaters (EWHs). The load‐shifting potential of Australia was estimated for each hour of the simulation period using a nationwide aggregate EWH load model on a 90 × 110 raster grid. The electricity demand of water heaters was shifted from periods of low renewable resource and high demand to periods of high renewable resource and low demand, enabling us to effectively reduce the installed capacity requirements of a 100%‐renewable electricity grid. It was found that by shifting the EWH load by just 1 hour, the electricity demand of Australia could be met using purely renewable electricity at an installed capacity of 145 GW with a capacity factor of 30%, an electricity spillage of 20%, and a generation cost of 15.2 ¢/kWh. A breakdown of the primary energy sources used in our scenario is as follows: 43% wind, 29% concentrated solar thermal power, and 20% utility photovoltaic. Sensitivity analysis suggested that further reduction in installed capacity is possible by increasing the load‐shifting duration as well as the volume and insulation level of the EWH tank.     

Persistence of low wind speed conditions and implications for wind power variability

As the penetration of wind generation increases on power systems throughout the world, the effects of wind variability on power systems are of increasing concern. This study focuses on sustained occurrences of low wind speeds over durations ranging from 1 h to 20 days. Such events have major implications for the variability of energy yields from wind farms. This, in turn, influences the accuracy of wind resource assessment. The frequency analysis techniques commonly used to study wind variability cannot represent the autocorrelation properties of wind speeds and thus provide no information on the probabilities of occurrence of such sustained, low wind events. We present two complementary methods for assessing wind variability, runs analysis and intensity–duration–frequency analysis, both with emphasis on characterising the occurrence of continuous, extended periods (up to several days) of low wind speeds. Multi‐annual time series of hourly wind speeds from meteorological stations in Ireland are analysed with both techniques. Sustained 20‐day periods corresponding to extremely low levels of wind generation are found to have return periods of around 10 years in coastal areas. Persistent, widespread low wind speed conditions across the entire country are found to occur only rarely. Copyright © 2012 John Wiley & Sons, Ltd.     

A review on the design and control strategy of energy storage system in wind power application

随着风力发电大规模入网,其随机性,波动性和间歇性特征对电力系统调频,调峰等有功平衡手段及电压稳定的影响越来越严重.储能系统能够在一定程度上控制风场的输出功率,平抑风电功率波动,改善风机低电压穿越能力,甚至为系统提供辅助服务,是从风场侧提高系统对风电的接纳能力的可行解决方案之一.作者在简要的介绍了风场储能技术应用现状的基础上,重点针对储能型风场内蓄电池储能系统的设计方案,容量优化及控制策略的研究现状及关键问题进行综述及探讨.     

Coordinated control of a hybrid type 3 wind turbine and hydrogen energy storage model to provide efficient frequency control

The growing share of generation from wind farms is becoming one of the challenges in maintaining the sustainability of electric power systems. System operators approve requirements for the participation of such plants in frequency and power regulation, but they do not contain requirements for specific technologies in the control of wind turbines. There are several methods of frequency and power control, which are implemented by additional control systems, the implementation of underload mode, extraction of hidden inertia, the use of energy storage devices, etc. Each of these methods has both advantages and disadvantages. In this paper we consider the combined coordinated control of type 3 wind turbines using kinetic energy and energy from hydrogen storage to provide the best frequency response in order to minimize the negative factors. A digital-analog-physical model of type 3 wind turbine is used as a model, which allows to reproduce the whole range of transients most accurately and avoid the limitations of strictly numerical simulation.     

Torsional torque suppression of generator based on H∞ control theory in isolated power system

Renewable energy power plants, such as wind turbine generator and photovoltaic system, have been introduced in isolated power system recently. The output power fluctuations of wind turbine generator and load deviations result in frequency deviation and terminal voltage fluctuation. Furthermore, these power fluctuations also affect the turbine shafting of diesel generators and gas‐turbine generators, which are the main components of power generation systems in isolated islands. For stable operation of gas‐turbine generator, the torsional torque suppression as well as power system stabilization should be considered. In this paper, the control strategy that achieves torsional torque suppression and power system stabilization is presented based on H_∞ control theory. The effectiveness of the proposed control system is validated by numerical simulation results. Copyright © 2010 John Wiley & Sons, Ltd.     

A review of grid code technical requirements for wind farms

This paper provides an overview of grid code technical requirements regarding the connection of large wind farms to the electric power systems. The grid codes examined are generally compiled by transmission system operators (TSOs) of countries or regions with high wind penetration and therefore incorporate the accumulated experience after several years of system operation at significant wind penetration levels. The paper focuses on the most important technical requirements for wind farms, included in most grid codes, such as active and reactive power regulation, voltage and frequency operating limits and wind farm behaviour during grid disturbances. The paper also includes a review of modern wind turbine technologies, regarding their capability of satisfying the requirements set by the codes, demonstrating that recent developments in wind turbine technology provide wind farms with stability and regulation capabilities directly comparable to those of conventional generating plants.     

Adequacy evaluation of wind power generation systems

This paper attempts to assess the adequacy of wind power generation systems using the data collected from seven wind farms in Muppandal, Tamilnadu (India) with a total capacity of 37 MW. A Monte Carlo model simulation is incorporated in the algorithm to obtain the hourly power output of wind farms, which also takes into account the unavailability of wind turbines. A typical load demand profile is used to examine the chronological hourly wind power generation for each month. The reliability index of LOLE (loss of load expectation) is used to estimate the reliable contribution of wind farm power generation.     

基于混合深度学习的风电功率预测及一次调频应用

为了解决高比例不确定性风电接入电力系统带来强烈调频需求的问题,提出了基于混合深度学习模型的风电功率预测及其一次调频应用方法。首先,采用孤立森林(Isolated Forest, IF)对历史数据进行异常值处理,提高数据质量,其次,构建卷积神经网络(Convolutional Neural Network, CNN)、双向长短期记忆(Bidirectional Long Short Term Memory, BiLSTM)和注意力机制(Attention Mechanism, AM)的混合深度学习模型对风电功率进行预测。最后,依据功率预测精度配置超级电容器储能,设计储能调频控制原则,弥补风电机组自身预测误差,并协同风电机组参与电力系统一次调频。基于预测结果为4台风电发电机组2个负荷区域仿真系统配置超级电容器储能系统,利用digsilent平台进行了风预测误差和负荷波动下的一次调频仿真。结果表明：所提IF-CNN-BiLSTM-AM模型比BP和LSTM基准模型预测误差(MSE)降低了81.53%和51.44%,具有最优的预测性能;设计的风储一次调频模型与原则可有效应对风电预测误差和负荷波动...     

Fractional‐order sliding mode control for hybrid drive wind power generation system with disturbances in the grid

The proposal of hybrid drive grid‐connected wind turbine based on speed regulating differential mechanism (SRDM) has been made in this paper to generate constant‐frequency power without fully‐ or partially‐rated frequency converters so as well improve electric power quality. However, disturbances in the power grid including sudden load fluctuation and sub‐synchronous resonance (SSR) can lead to the pulsating torque to act on the shaft section between SG and exciter at the main generator collector, such that the speed regulating accuracy of SRDM is seriously affected. As a result, this paper synthesizes a new‐type fractional‐order sliding mode controller (FOSMC) with a load torque observer (LTO) for the high‐accuracy speed control of permanent magnet synchronous motor (PMSM) in SRDM. Taking advantage of ridge regression algorithm, related parameters including rotational inertia and viscous friction coefficient of speed regulating system are calculated accurately. Finally, comparative experiments are carried out under four cases of mean of 5, 10, 13, and 21 m/s wind speeds to verify the satisfactory performances of designed FOSMC with LTO. Comparative experimental results show that FOSMC with LTO can effectively eliminate undesirable chattering effect. Additionally, under operating conditions of changing wind speeds, SSR, and sudden load fluctuation in power grid, the output speed of SRDM that corresponds directly to the frequency output of SG can be steadily and accurately regulated by using proposed control scheme. SRDM equipped with designed controller enables the power frequency to meet the National Standard of PR China perfectly.     

Operating policies for wind-pumped storage hybrid power stations in island grids

Pumped storage is today viewed as the most suitable storage technology for achieving high wind penetration levels in multi-megawatt-sized autonomous island grids, where the technical constraints introduced by the conventional generating units impose limitations on the output of wind farms. In this study, an operating policy is proposed for hybrid wind-hydro power stations (HPSs) in island grids, to increase wind penetration levels, while at the same time minimising the impact on the conventional generation system and ensuring the viability of the HPS investment. The proposed operating strategy is applied to three different autonomous island systems using a dedicated logistic model, to evaluate the effect of the HPS on the overall operation and economics of the island systems and to assess the feasibility of HPS investments.     

Computational environment to investigate wind integration into small autonomous systems

This paper presents briefly the methodologies and the respective computational tools for the investigation of the wind power exploitation in small autonomous power systems supplying the load demand of small islands. The proposed methodology examines the wind power penetration from both technical and economic point of view. It comprises tools for load forecasting and management, power system analysis and generation system simulation and planning.     

解决新疆风能资源大规模开发瓶颈的探讨

本文对如何解决新疆风能资源进行大规模开发时所遇到的瓶颈进行了探讨,提出了一种解决问题的新思路。用详细的数据介绍了新疆丰富的风能资源分布,讨论了在大规模开发时遇到的电网稳定性、有效负荷需求不足以及没有联网电网的支持等问题,最后,根据新疆拥有丰富的天然气资源,提出了采用一种新型的风电-燃气轮机互补发电系统来彻底解决风电场负荷的波动对电网稳定性不利的影响,为新疆的风能大规模开发提供了一种新的可能。     

Review on combined wind power generation and energy storage systems

储能系统由于能够实现电能的时空平移,具有响应速度快,规模化等优点,是改善风电波动性,提高其并网能力的有效手段,构建风储联合发电系统成为目前研究重点.简单介绍了风电并网对电力系统的影响及不同类型电池储能技术的发展现状,给出了部分国内外风储联合发电系统的示范工程,并分析了平滑风电功率波动,跟踪计划出力曲线和削峰填谷3种主要运行方式,重点阐述了目前风储联合发电系统控制策略和储能容量配置研究现状,对进一步开展风储联合发电系统的研究进行了展望,指出经济性仍然是制约储能技术应用的关键问题之一,提高包含储能单元的风储联合发电系统的经济性是今后的研究重点.     

Impact of wind power in autonomous power systems—power fluctuations—modelling and control issues

This paper describes a detailed modelling approach to study the impact of wind power fluctuations on the frequency control in a non‐interconnected system with large‐scale wind power. The approach includes models for wind speed fluctuations, wind farm technologies, conventional generation technologies, power system protection and load. Analytical models for wind farms with three different wind turbine technologies, namely Doubly Fed Induction Generator, Permanent Magnet Synchronous Generator and Active Stall Induction Generator‐based wind turbines, are included. Likewise, analytical models for diesel and steam generation plants are applied. The power grid, including speed governors, automatic voltage regulators, protection system and loads is modelled in the same platform. Results for different load and wind profile cases are being presented for the case study of the island Rhodes, in Greece. The scenarios studied correspond to reference year of study 2012. The effect of wind fluctuations in the system frequency is studied for the different load cases, and comments on the penetration limits are being made based on the results. Copyright © 2010 John Wiley & Sons, Ltd.     

Optimal operation of DC smart house system by controllable loads based on smart grid topology

From the perspective of global warming mitigation and depletion of energy resources, renewable energy such as wind generation (WG) and photovoltaic generation (PV) are getting attention in distribution systems. Additionally, all-electric apartment houses or residence such as DC smart houses are increasing. However, due to the fluctuating power from renewable energy sources and loads, supply-demand balancing of power system becomes problematic. Smart grid is a solution to this problem. This paper presents a methodology for optimal operation of a smart grid to minimize the interconnection point power flow fluctuation. To achieve the proposed optimal operation, we use distributed controllable loads such as battery and heat pump. By minimizing the interconnection point power flow fluctuation, it is possible to reduce the electric power consumption and the cost of electricity. This system consists of photovoltaic generator, heat pump, battery, solar collector, and load. To verify the effectiveness of the proposed system, results are used in simulation presented.     

考虑分布式电源接入的电网源荷时序随机波动特性概率潮流计算

鉴于分布式电源的时序随机波动特性和负荷需求侧的电能质量是分布式电源接入系统的重要影响因素,从风光典型分布式电源和负荷需求的时序波动性出发,建立了综合考虑源荷时序特性的概率潮流计算模型。利用基于模糊特征聚类的概率潮流算法对IEEE 14节点系统进行计算,对比分析负荷需求侧对系统电压波动的影响情况。结果表明,所采用方法能够全面合理地模拟分布式电源接入时电网随机波动过程。     

集团型风电企业综合联网监控管理系统的构建

以五大发电集团为代表的集团型风电企业已经成为我国风电投资开发的主体力量,如何管控好数量急剧增加的风电场成为企业安全生产中重要的课题。从风电场安全视频监控的角度,针对其普遍实行的三级责任主体的管控模式,提出了一种综合联网监控管理系统的构建方案。从需求分析、系统设计思路、系统的详细设计3个方面进行了阐述,其中专业网络视频管理系统是整个系统的核心,要求其具有容量大,承载能力强,可靠性好,扩展性、兼容性强的特点,且能容纳业已存在的若干风场的视频监控系统。文中提出的方案对集团型风电企业的综合联网监控管理系统的构建具有借鉴作用。     

Impact of wind farms on a power system. An eigenvalue analysis approach

This paper analyzes the frequency dynamic behavior in a power system with a high wind power penetration. To this end, wind farms equipped with squirrel cage and doubly fed induction generators are compared. Aspects of the modeling of the different kinds of wind generation and power systems are cited. Then, it is shown, through an eigenvalue analysis, that wind farms equipped by doubly fed induction machines, adequately controlled, can contribute to improve the frequency dynamics. Simulations are presented which verify the theoretical results.     

包含风电的电力系统调峰能力计算方法探讨

在我国风电大规模并网的背景下,针对水火电混合系统,结合风电并网后系统负荷特性的变化情况,提出并分析了一种更接近于电网实际调峰能力的计算方法。该方法对风电接入后电网实际调峰能力的研究有借鉴意义。