Frequency Control of Power System with Renewable Power Sources by HVDC Interconnection Line and Battery Considering Energy Balancing

Recently, introduction of renewable energy sources like wind power generation and photovoltaic power generation has been increasing from the viewpoint of environmental problems. However, renewable energy power supplies have unstable output due to the influence of weather conditions such as wind speed variations, which may cause fluctuations of voltage and frequency in the power system. This paper proposes fuzzy PD based virtual inertia control system to decrease frequency fluctuations in power system caused by fluctuating output of renewable energy sources. The proposed new method is based on the coordinated control of HVDC interconnection line and battery, and energy balancing control is also incorporated in it. Finally, it is concluded that the proposed system is very effective for suppressing the frequency fluctuations of the power system due to the large-scale wind power generation and solar power generation and also for keeping the energy balancing in the HVDC transmission line.

Effect of Energy Market Globalization over Power Sector of GCC Region: A Short Review

Globalization of energy market in GCC countries is deepening not only through free-flowing international trade but also through foreign investment, market-driven domestic economies and industrialization. GCC nations are transforming their energy industry and market around the world which is promising their economic efficiency and technology development. Nevertheless, this open energy market across the world has raised a question about energy security and power demand. This energy market globalization has pushed the GCC Nations to pay attention to the control of supply and demand of power. Interconnection of power network between the GCC Region is optimistic pace to secure the future anticipated power fallouts. And also installation of Renewable Energy projects will support GCC to accommodate their increasing power demand. This paper discusses about how the energy market globalization has effect the power supply and demand of GCC nations, their concerns and recent progress towards its resolution.

High Proportion Renewable Energy Supply and Demand Structure Model and Grid Impaction

In considering of high proportion of renewable energy supply in 2050, the accelerating of energy consumption gross, source and environment can affect the energy system restrict affection are stronger. Add wind and solar to electricity energy with large amount of energy source exploitation. The energy source amount per person is lower. Considering the renewable energy amount and supply, primary energy storage and structure problem is standing out. Before the wide spread of renewable energy, Using the high-carbon energy in China can pollute seriously. Chinese energy supply and demand problem is research key point. This paper researches Chinese energy supply and demand pattern system and evaluation methodology, gives out the inner and outer influencing elements. And evaluate Chinese energy supply and demand pattern from energy gross, structure, distribution and transportation. Use energy supply synthesize radar comparison chart in certain time period. From energy security, economy, clean and efficiency, analyze the benefit comparisons of Chinese energy supply and demand pattern. This energy supply and demand pattern model will give one certain theoretical analysis and practice reference to the further high proportion of renewable energy.

Present status of pumped hydro storage operations to mitigate renewable energy fluctuations in Japan

This paper focuses on pumped hydro energy storage(PHES)plants’current operations after electricity system reforms and variable renewable energy(VRE)installations in Japan.PHES plants have historically been developed to create electricity demand at night in order to operate base load power plants,such as nuclear power plants,in stable conditions.Therefore,many PHES plants are located midway between nuclear power plants and large demand areas.However,all nuclear power plants had to–at least temporarily–shut down after the Great East Japan Earthquake followed by a nuclear accident at Fukushima Daiichi in 2011,and renewable energy power plants have been deployed rapidly after the introduction of a feed-in-tariff(FIT)scheme.Therefore,PHES plants are being used to mitigate fluctuations of VRE,especially in areas where renewable energy has been significantly installed.The daily highest capacity ratio of PHES plants in Kyushu area has recorded three times higher than it in the other areas where the past operating mode is still conducted.But those operations on PHES plants are simply followed as a dispatch rule of the Organization for Crossregional Coordination of Transmission Operators(OCCTO),market-based operations have not been conducted enough yet.The market design shall be changed to harmonize VRE installation and PHES plants’operations are necessary to make the transition from the past operating mode of PHES plants across Japan.

Control and Stability of Large-scale Power System with Highly Distributed Renewable Energy Generation:Viewpoints from Six Aspects

Power systems are moving toward a low-carbon or carbon-neutral future where high penetration of renewables is expected.With conventional fossil-fueled synchronous generators in the transmission network being replaced by renewable energy generation which is highly distributed across the entire grid,new challenges are emerging to the control and stability of large-scale power systems.New analysis and control methods are needed for power systems to cope with the ongoing transformation.In the CSEE JPES forum,six leading experts were invited to deliver keynote speeches,and the participating researchers and professionals had extensive exchanges and discussions on the control and stability of power systems.Specifically,potential changes and challenges of power systems with high penetration of renewable energy generation were introduced and explained,and advanced control methods were proposed and analyzed for the transient stability enhancement of power grids.

Communication Resources Allocation for Time Delay Reduction of Frequency Regulation Service in High Renewable Penetrated Power System

The high renewable penetrated power system has severe frequency regulation problems.Distributed resources can provide frequency regulation services but are limited by com-munication time delay.This paper proposes a communication resources allocation model to reduce communication time delay in frequency regulation service.Communication device resources and wireless spectrum resources are allocated to distributed resources when they participate in frequency regulation.We reveal impact of communication resources allocation on time delay reduction and frequency regulation performance.Besides,we study communication resources allocation solution in high renewable energy penetrated power systems.We provide a case study based on the HRP-38 system.Results show communication time delay decreases distributed resources'ability to provide frequency regulation service.On the other hand,allocating more communication resources to distributed resources'communica-tion services improves their frequency regulation performance.For power systems with renewable energy penetration above 70%,required communications resources are about five times as many as 30%renewable energy penetrated power systems to keep frequency performance the same.Index Terms-Communication resources allocation,commun-ication time delay,distributed resource,frequency regulation,high renewable energy penetrated power system.

Optimal allocation method of energy storage for integrated renewable generation plants based on power market simulation

This study designs and proposes a method for evaluating the configuration of energy storage for integrated re-newable generation plants in the power spot market,which adopts a two-level optimization model of“system simulation+plant optimization”.The first step is“system simulation”which is using the power market simu-lation model to obtain the initial nodal marginal price and curtailment of the integrated renewable generation plant.The second step is“plant optimization”which is using the operation optimization model of the integrated renewable generation plant to optimize the charge-discharge operation of energy storage.In the third step,“sys-tem simulation”is conducted again,and the combined power of renewable and energy storage inside the plant is brought into the system model and simulated again for 8,760 h of power market year-round to quantify and compare the power generation and revenue of the integrated renewable generation plant after applying energy storage.In the case analysis of the provincial power spot market,an empirical analysis of a 1 GW wind-solar-storage integrated generation plant was conducted.The results show that the economic benefit of energy storage is approximately proportional to its capacity and that there is a slowdown in the growth of economic benefits when the capacity is too large.In the case that the investment benefit of energy storage only considers the in-come of electric energy-related incomes and does not consider the income of capacity mechanism and auxiliary services,the income of energy storage cannot fulfill the economic requirements of energy storage investment.

Economic potentials of energy storage technologies in electricity markets with renewables

The increasing penetration of renewables in power systems urgently entails the utilization of energy storage technologies.As the development of energy storage technologies depends highly on the profitability in electricity markets,to evaluate the economic potentials for various types of energy storage technologies under the compre-hensive market environment is of great significance.To this end,this study aims at conducting a quantitative analysis on the economic potentials for typical energy storage technologies by establishing a joint clearing model for electric energy and ancillary service(AS)markets considering the operating features of energy storage systems(ESSs).Furthermore,a test system is adopted for numerical analysis that accurately represents for the real-world operation characteristics of power systems in China,with which the market prices,and operation schedules and profitability of ESSs are comparatively studied.The proposed methodology and results could provide benefi-cial references for the modifications on electricity markets and the development of ESSs towards the increasing penetration of renewables in power systems.

KPI-based Real-time Situational Awareness for Power Systems with a High Proportion of Renewable Energy Sources

With the increasing complexity of power systems and the widespread penetration of renewable energy sources(RES),real-time situational awareness for power systems is of great significance for operational scheduling.Considering the impact of RES on power system operations,a situational awareness key performance index(KPI)system for power systems with a high proportion of RES is proposed in this paper,which consists of reserve capacity abundance,ramp resource abundance,center of inertia(COI)frequency deviation,interface power flow margin,synthesized voltage stability,and angle stability margin.Then,the KPIs are synthesized and visualized by the decision tree method and radar chart method,respectively,for monitoring the operation states(i.e,normal,alert,and emergency states)of power systems with a high proportion of RES.Numerical simulations are conducted in a revised New England 16-machine 68-bus power system and an actual CEPRI-RE power system in the northwest region of China with a high proportion of RES.The results show that the proposed KPI-based situational awareness method is able to accurately monitor the real-time state of power systems with a high proportion of RES,and can assist power dispatchers to make effective decisions.

西北电网集中式调相机AVC综合协调控制策略

为实现西北电网高比例新能源地区的无功优化控制,提出了一种高压直流换流站集中式调相机参与电网自动电压控制(automatic voltage control,AVC)的综合协调控制策略。首先分析了AVC的总体控制思路,按“软分区”思想构造了三级电压控制模式。针对西北电网和青海电网实际,在网省系统之间建立协调控制变量,结合最优潮流模型,形成了柴达木调相机参与AVC的综合协调控制策略。通过柴达木调相机AVC联调试验时偶遇的电网大扰动实例,验证了控制策略的良好适用性。所提出的AVC控制策略,可使调相机在电网稳态时发挥无功源作用,电网故障时提供瞬时强无功支撑,充分利用新一代调相机性能,提高电网无功电压调节水平。

考虑实时备用率的中长时间尺度新能源发电备用的方法

在新型电力系统中,考虑到中长期时间尺度下新能源出力具有较强规律性,提出了中长时间尺度新能源纳入备用的实时备用率的确定方法。根据实时备用率将新能源可信出力纳入备用,建立多电源电力生产模型。所建模型以生产成本最小为目标函数,考虑电源运行成本、新能源弃电成本、切负荷惩罚成本及机组出力、功率平衡、逻辑变量等约束条件。采用时间迭代将中长时间生产模拟化简为短期优化问题,利用CPLEX求解。以改进IEEE-24节点系统作为算例,优化结果表明新能源电源采用实时备用率的方法纳入备用时,电力系统生产运行总成本更低;新能源渗透率越高,纳入新能源为备用的经济效益越明显;风电和光伏独立确定备用率时,备用成本和污染排放更低。

适应新型电力系统的电力互替品市场——(一)理念与构想

新型电力系统重塑了能源生产消费结构,电力市场机制也需随之改变。首先,分析指出提升系统调节能力是新型电力系统下市场机制设计的首要目标;围绕该目标给出了市场机制应具备的特点,包括利于激发调节动力、释放调节能力、接纳各种新型调节资源等。其次,对世界各国现货市场普遍采用的分时交易机制进行了分析,指出其与新型电力系统存在诸多不适应之处,包括市场主体调节贡献无法被量化表征,市场主体连续运行特性与分时交易机制相矛盾、调节能力难以完全释放,以及难以满足海量柔性资源直接参与电力市场的需求等。为此,文中舍弃分时交易的方式,转而提出整体交易机制与电力互替品概念,介绍了形成与交易电力互替品的主要思路,并以电力互替品为核心构想了新型市场机制。该机制可通过调节责任划分量化各主体调节贡献,激发市场主体的调节动力;同时,也能促进市场主体主动优化自身运行方式,释放调节能力;具有易于扩展的优势,可轻松接纳新型电力系统下层出不穷的各类新型主体。

水电高占比下风电接入对系统稳定性影响

随着绿色清洁高效能源基地的构建,以水电为主体的水风互补成为我国西南能源开发的重要特征。为研究在典型水电系统中接入风电对系统稳定性带来的影响,首先,针对水风互补系统以转矩分析法分析了风电接入对系统频率和功角稳定性的影响,并通过算例和Prony分析验证了风速与风电渗透率对系统稳定性的影响。结果表明,风电的接入在一定程度上可以削弱传统水电系统的超低频振荡,而风电接入互联送端系统会导致区域等值惯量的下降,进而使系统区域间低频振荡风险加剧。其次,考虑风电的接入会诱发区域间低频振荡,在风电系统中引入风电的附加综合虚拟惯性与阻尼控制。算例与Prony分析验证了该控制策略能有效提高系统稳定性。最后,在区域间大规模风电接入场景下,利用改进的鲸鱼算法对风电的附加控制器参数进行了优化;结果表明,参数的整定有效提高了系统的频率以及功角稳定性。

基于海博平台的可再生能源电力市场空间分析软件开发研究

为了更好地服务指导国际可再生能源市场开发,进一步完善和提升海博平台的规划功能,开发了一种基于海博平台的可再生能源电力市场空间分析计算软件,形成了一套可靠的完备的规划分析计算流程,可以实现可再生能源资源评估、负荷预测、电力电量平衡分析、电源规划、系统经济性计算等分析计算功能,提高规划工作的系统性,提高成果的科学合理性,并基于软件计算提出可再生能源开发利用方案及综合能源多能互补基地布局建议。该软件具有较强的创新性和良好的应用前景,可供实际工程参考。

基于多市场耦合的新能源综合发电项目的盈利能力研究

为解决我国新能源发电产业扩张引发的弃风弃光问题,引入氢储能系统与风能、太阳能光伏发电配合,构建新能源综合发电项目。为解决预算赤字问题,提出碳减排市场(carbon certified emission reduction,CCER)与综合项目结合,构建市场交易模型。为评估项目平准化度电成本(levelized cost of electricity,LCOE),基于现有风、光发电基础,引入氢储能系统成本和“氢-电”收益、氢能收益、氧气收益、碳排放收益,建立优化的平准化度电成本(optimizing levelized cost of electricity,OLCOE)模型。以我国西北某省风、光电厂为例,设定3种盈利情景,计算项目的OLCOE。选取符合实际效益的模型,以传统燃煤上网电价为新能源上网电价,在不同氢能和碳排放定价下进行敏感性分析,深入研究综合发电项目的盈利能力。研究表明:多市场辅助对新能源综合发电项目的发展不仅增强其盈利潜力,还能补偿高额的建设成本,从而提高项目的可行性。此外,可持续发展政策的有效实施和技术的进步也将进一步推动项目的未来发展。

面向东北电网调峰辅助服务市场交易主体的分摊上限动态机制设计

东北电网现行的调峰辅助服务市场机制难以应对市场结构变化带来的交易主体实际调峰收益低于预期、积极性降低等问题,且难以满足未来我国以新能源为主体的新型电力系统发展需求。在介绍东北电网现行调峰辅助服务市场费用分摊机制的基础上,分析其局限性,提出面向市场参与主体的分摊上限动态调整机制,以保障调峰供应方的调峰收益;构建以市场交易主体综合收益最高为目标的动态分摊上限数学模型,并提出用于评估调峰辅助服务市场的指标体系。基于辽宁省电网实际运营数据的算例结果验证了所提机制的合理性与有效性。

基于切片采样-马尔科夫链蒙特卡洛模拟的高比例新能源电力系统等效惯量概率评估

风电、光伏新能源发电功率的不确定性给高比例新能源电力系统的等效惯量评估带来了新的挑战。基于确定性的惯量评估方法不能有效反映全分析时段高比例新能源电力系统惯量的时序变化态势。为了评估新能源波动所引起的系统惯量不确定性,该文提出了一种基于切片采样–马尔科夫链蒙特卡洛模拟(slice sample Markov chain Monte Carlo,S-MCMC)的系统等效惯量概率评估方法。首先,对高比例新能源电力系统惯量组成及特性进行了分析,并对同步旋转设备的有效机械惯量、风电光伏电源的有效虚拟惯量进行量化计算。然后,基于Copula函数建立风速和光照强度之间的相关性模型,利用S-MCMC对系统等效惯量进行概率评估,从而得到系统等效惯量时序变化区间。最后,以改进的IEEE 39节点系统进行仿真分析,验证了所提出方法及分析结果的有效性。

电压源型风电比例影响区域电网频率调整研究

随着新能源大比例接入新型电力系统中,区域电网的频率稳定性问题凸显。为了研究风电在区域电网中对新能源系统稳定运行能力的影响,针对电压源型风电占比对区域电网频率调整的影响开展研究。对风电频率需求相应特性和电压源型风电机组控制进行分析,提出了在电压源型风电机组不同占比结构下的区域电网新能源场站容量分配评估方法。在Matlab/Simulink中对不同电压源型风电占比下的电网频率响应特性进行验证。结果表明,随着在混合风电场内配置一定比例的电压源型风电机组,可以有效地改善区域电网的频率稳定性。

德国电力市场能源转型建设及启示

中国正在推进能源结构清洁化转型。如何通过市场建设促进新能源高比例消纳是能源结构调整重点关注的问题。国外电力市场在支撑能源转型方面具有较为丰富的可借鉴经验,以德国电力市场为借鉴对象,对比总结其促进新能源消纳的过程和成效,可为内蒙古电力市场建设提供有益参考。首先分析对比内蒙古自治区与德国在能源供给和消费总量、新能源装机和消纳方面的水平差距;其次介绍德国电价体系和电力市场体系,并通过参考因素的平均绝对误差指标对德国电力市场在适应高比例新能源方面的运行成果进行深度分析;最后总结德国电力市场建设在政策与市场衔接、跨国大市场建设和区域自平衡机制等方面的经验,并提出适应内蒙古电力市场建设的建议。

考虑新能源高阶不确定性的交直流混联电网静态电压稳定裕度计算

随着大量新能源场站接入交直流混联电网,系统的静态电压稳定裕度(static voltage stability margin,SVSM)水平具有很大的不确定性,需要研究考虑新能源场站高阶不确定性的交直流混联电网SVSM计算方法。针对此问题,首先建立了交直流混联电网SVSM计算模型,模型中考虑了直流换流站控制方式随负荷增长的切换;采用概率盒模型描述风速与光照强度的随机波动,提出了改进区间半不变量法以获得更准确的SVSM概率盒,该方法通过K-means++聚类算法将随机变量样本划分为多个波动范围较小的样本集,以降低半不变量的线性化计算带来的误差;并结合Gram-Charlier级数展开和概率加权和计算得到考虑新能源场站高阶不确定性的系统SVSM概率盒。通过对修改的IEEE-39节点交直流系统和南方电网两个算例的分析,并与区间半不变量法和双层蒙特卡洛法比较,验证了所提出方法获得的SVSM概率盒具有较高的计算精度和效率。