Simulation of Underground Reservoir Stability of Pumped Storage Power Station Based on Fluid-Structure Coupling

Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional reservoir.In particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and stability.Using the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground reservoir.First,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground reservoir.Next,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground reservoir.Finally,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening measures.The findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project area.The underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was higher than 1,indicating that the project as a whole is in a stable state.

Study on integrated development and hybrid operation mode of nuclear power plant and pumped-storage power station

The nuclear power plant is suitable for base-load operation, while the pumped-storage unit mainly gives play to capacity benefit in the electric power system;hence, the integrated development and hybrid operation mode of the two can better meet the needs of the electric power system. This article first presents an analysis of the necessity and superiority of such mode, then explains its meaning and analyzes the working routes. Finally, it proposes the business modes as follows: low price pumping water electricity plus nuclear power in the near term;nuclear power shifted to pumped storage power participating in market competition in the middle term;and, in the long term, nuclear power shifted to pumped storage power as primary and serving as an electric power system when needed.

Prospect of new pumped-storage power station

In this paper, a new type of pumped-storage power station with faster response speed, wider regulation range, and better stability is proposed. The operational flexible of the traditional pumped-storage power station can be improved with variable-speed pumped-storage tech no logy. Combined with chemical en ergy storage, the failure to achieve sec on d-order response speed and the insufficient safety and reliability of pumped-storage power units could be solved. With the better solar en ergy and site resources, the in teg rated performance can be improved by an optical storage system in stalled in future pumped-storage stations. Through the characteristics analysis of the new type of pumped-storage power station, three types of optimal station locations are proposed, namely, the load concentration area, new energy concentration area, and ultrahigh- voltage direct current receiver area. Taking the new pumped-storage power station as an example, the advantages of multi-energy cooperation and joint operation are analyzed. It can be predicted that the frequency and load regulation of the power grid will be more flexible, and the service capacity to the main power grid will be much stronger in the future.

A novel technology for control of variable speed pumped storage power plant

Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.

Equivalent Substitution Based Method for Calculation of Best Installed Capacity of Pumped Storage Power Station

This paper proposes a novel method to calculate the best installed capacity of pumped storage power station. First, we choose the day with maximum load as the typical day for every month and simulate the system running in two cases of whether the pumped storage power station is put into operation. The difference of the total coal consumption between the two cases is the peak load shifting benefit. Furthermore, we build load model and power generation model to calculate the benefit of emergency use and frequency modulation, which are the major projects of dynamic benefits. At last, on the premise of ensuring the system requirements, the developed method employs the maximum benefit of the unit capacity as the objective function to get the best installed capacity of pumped storage power station by simulations. Tests on a provincial power grid have shown that the developed method which combines of load characteristics, electric structure and other factors can get the best installed capacity of pumped storage power station easily and has a certain guiding significance for the planning and construction of the pumped storage power station.

Effect of dry-wet cycles on dynamic properties and microstructures of sandstone:Experiments and modelling

Underground pumped storage power plant(UPSP)is an innovative concept for space recycling of abandoned mines.Its realization requires better understanding of the dynamic performance and durability of reservoir rock.This paper conducted ultrasonic detection,split Hopkinson pressure bar(SHPB)impact,mercury intrusion porosimetry(MIP),and backscatter electron observation(BSE)tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage.A coupling FEM-DEM model was constructed for reappearing mesoscopic structure damage.The results show that dry-wet cycles decrease the dynamic compressive strength(DCS)with a maximum reduction of 39.40%,the elastic limit strength is reduced from 41.75 to 25.62 MPa.The sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock particle.The pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles,which verifies the computational statistics analysis of particle deterioration.The numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are dominant.The dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields.

Test Facility for Low Potential Pumped Storage Power Plants and Hydrokinetic Turbines

The electric energy which is generated by wind power plants depends on the wind speed and exceeds with strong permissible wind speed the electric energy requirements of the country. In order not to reduce this electrical energy, it must be stored. The sensible energy storage is currently the pumped storage power plants. As the mountain ranges for conventional pumped storage power plants with drop heights of H 〉 600 m are strictly limited, the development of low potential pumped storage power plants has begun. Increasing the capacity of pumped storage power plants with regard to the wind power plants is urgently needed. In this paper, it is shown using the example of an unneeded port facility, how a port facility can be used after low conversion as a test facility for low potential pumped storage power plants and at the same time for the testing of hydro-kinetic turbines. This type of pump storage power plants does not save the energy due to large drop heights, but primarily due to the large volume flow of water.

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.

Optimal Dispatching Model Considering the Pumped Sto-rage Power Plant in Hunan

This paper made a research on the Intelligent Optimization Operating Modeling of Pumped Storage Power Station in Hunan Power Grid. First it introduces the characteristics of Hunan power grid and analysis the practical requirement of dispatching. Then it brings forward the intelligent optimization model and set up running model for pumped storage power station of Hei Mi-feng. At last, it introduces the application of pumped storage power station in Hunan power grid and proves the effectiveness of the optimization models.

Study of Local Structural Changes on Air Cooling at the End of Rotor Windings for Variable Speed Pumped Storage Generator-Motor

The shrink fit retaining ring is currently the easiest to install and the most widely used end fixed for structure AC excitation variable speed generator-motor rotor end windings.However,the current research on the effect of high strength sealing on the ventilation and heat dissipation performance of the end is not enough.In this paper,based on the actual structural parameters and periodic symmetry simplification,the three-dimensional coupled calculation model of fluid field and temperature field is established.After solving the fluid and thermal equations,the influence of the length of rotor support block,the height of rotor support block,and the number of rotor support block on the fluid flow and temperature distribution in the rotor end region of generator-motor is studied using the finite volume method.The rheological characteristics of the air in the rotor domain,such as velocity and inter-winding flow,are analyzed.The law of temperature variation with local structure in the computational domain is studied.The variation law of cooling medium performance inside the large variable speed power generator motor is revealed.

New Analytical Model for Optimal Placement of Wind Turbines in Power Network under Pool and Reserve Markets Conditions

In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PSHPPs) owners participate in power market. Objective function is defined as participants’ social welfare achieved from power pool and ancillary markets in yearly horizon. Wind turbines have been modeled by probability-generation tree scenarios based on statistical information. We concentrate on investment profits of WTs numbers and its generation capacity beside to PSHPPs and THUs power plants in power systems due to increase in high flexible tools for Independent system operator into the planning and operation planning time interval. For effectiveness evaluation of proposed model, simulation studies are applied on 14-Bus IEEE test power system.

基于Microstation及奥维地图的抽水蓄能电站施工总布置设计

抽水蓄能电站施工总布置设计涉及专业广、内容多、布置范围大,且设计周期不断被压缩,对工程设计人员要求逐渐提高,而传统的施工总布置设计方法效率较低,逐渐难以适应快节奏的设计工作。基于Microstation及奥维地图,利用多维设计手段以及GPS定位和导航功能,对抽水蓄能电站施工总布置设计进行研究。设计效果表明:基于Microstation及奥维地图的抽水蓄能电站施工总布置设计,提高了勘察设计效率及质量,减少了勘察设计失误,为抽水蓄能电站施工总布置设计提供了新思路。

计及深度调峰的风-光-水-火-抽蓄多能源联网系统优化调度研究

多种能源联网运行逐步成为未来电力系统发展的方向,多能源联网系统的优化调度是应对规模化新能源并网消纳的重要手段。文中建立了计及火电机组深度调峰成本的风-光-水-火-抽蓄联网系统成本模型和考虑调峰主动性的风-光-水-火-抽蓄联网系统日前优化调度模型。针对多能源耦合系统结构复杂的情况,提出了分层优化调度的模型求解策略。上层模型以净负荷波动最小为优化目标,得到等效负荷曲线;下层模型根据上层模型的调度结果,以调峰运行的经济性最优和新能源弃电率最低为目标函数,计及调峰主动性,求解考虑火电机组深度调峰煤耗特性的含新能源系统的经济调度问题。仿真算例表明所建模型实现了多能源联网系统的互补运行,提升了火电机组的深度调峰能力,降低新能源弃电率和系统运行成本。

抽蓄电站全库盆防渗水库渗流缺陷影响分析

针对抽蓄电站全库盆防渗水库土工膜缺陷导致水库渗流量产生变化的安全问题,结合陕西省某抽蓄电站水库库底土工膜防渗工程,采用单因素影响分析和多因素影响分析方法进行抽蓄电站全库盆防渗水库渗流缺陷影响分析。结果表明,水头大小、缺陷大小、缺陷个数均正向影响抽蓄水库渗流量,而缺陷位置与抽蓄水库渗流量的相关性不明显。其中缺陷大小是影响抽蓄水库渗流量的主要因素,其次为水头大小,再次为缺陷个数。

竖井式进出水口水力特性研究进展

竖井式进出水口是抽水蓄能电站水道系统两端控制水流的常用进出水口型式之一。竖井式进出水口双向过流,水流在短距离内经历两次90°流向转变(水平-竖直-水平),流向变化剧烈,水力条件复杂,深入研究竖井式进出水口水力特性,进而优化其体型结构,对抽水蓄能电站设计及施工具有重要意义。首先,介绍竖井式进出水口应用背景及体型特点,分析竖井式进出水口水力特性存在的问题;其次,对竖井式进出水口孔口流量分配、拦污栅断面流速分布、漩涡和水头损失等方面研究进展进行总结;最后,归纳了竖井式进出水口水力特性研究方法,探讨了今后研究应聚焦的主要方向。

侧式进/出水口各孔道流量分配差异及影响因素

对于抽水蓄能电站侧式进/出水口各孔道流量分配,现有设计规范规定进/出水口相邻中边孔道的流量不均匀程度不宜超过10%,但实际工程设计难以达到此要求.本文以某抽水蓄能电站侧式进/出水口为例,通过优化进/出水口各体型参数,利用数值模拟方法研究各孔道流量等水力参数,重点分析分流墩布置对各孔道流量分配的影响及其规律,试图使进流工况和出流工况相邻中边孔道的流量不均匀程度均最小.研究表明,改变扩散段分流墩布置能有效改善流量不均匀程度.对于3墩4孔侧式进/出水口,相邻中边孔道的流量不均匀程度在出流工况下随中边孔宽度比增大而增大,在进流工况下随中边孔宽度比增大而减小;当中边孔宽度比增大且中墩后移距离减小时,出流工况和进流工况下的流量不均匀程度均减小.对于2墩3孔侧式进/出水口,相邻中边孔道的流量不均匀程度不论在出流工况下还是在进流工况下,均随中边孔宽度比增大呈先减小后增大的规律.优化后的3墩4孔侧式进/出水口的中边孔宽度比取0.228∶0.272,中墩后移距离取0.36D(D为隧洞直径),其相邻中边孔道的流量不均匀程度均较优,在出流工况下为18.47%~19.43%,在进流工况下为19.82%~19.83%;优化后的2墩3孔侧式进/出水口的中边孔宽度比取0.310∶0.345,其相邻中边孔道的流量不均匀程度均较优,在出流工况下为19.47%~19.63%,在进流工况下为18.66%~18.67%.相邻中边孔道的流量不均匀程度较难满足不宜超过10%的设计规范要求.研究成果将有助于《抽水蓄能电站设计规范》中关于进/出水口水力指标要求的完善.

混合式抽水蓄能电站对下泄水温影响的数值模拟研究

【目的】混合式抽水蓄能电站运行特性与常规电站相比存在差异,本文旨在掌握抽水蓄能电站水温的变化规律,为水库管理调度提供参考。【方法】以紧水滩水库为研究对象,采用MIKE3水温模型模拟不同进/出水口高程以及不同抽水流量工况的下泄水温,据此探讨混合式抽水蓄能电站对下泄水温的影响。【结果】抽蓄水流会对下泄水温产生影响,相对于现状无抽水工况的下泄水温,抽蓄工况下的下泄水温基本表现为5—9月略有下降,其余月份略有升高,下泄水温的最大降幅不超过0.7℃,最大升幅不超过0.8℃。【结论】进/出水口高程对于下泄水温影响较大,且高程越低,下泄水温差异越大。然而抽水流量对于下泄水温差异影响并不显著,但整体上也呈现出随着抽水流量增加,水温差异增大的趋势。

NB/T 35009-2024修订内容解读及抽水蓄能电站标准化工作历程回顾

本文回顾了抽水蓄能电站选点规划标准化工作历程,从90年代选点规划工作范围逐步扩展,一批代表性站点规划落地,选点规划思想逐渐成熟,首版标准于2003年编制完成。到2009年全国范围抽水蓄能电站选点规划系统性开展,继22个省(区、市)完成选点工作,第二版标准修订完成,有效指导了实践工作。随着抽水蓄能电站选点规划的管理流程和技术路线不断成熟,选点规划已成为前期工作和开工建设的重要基础。双碳目标提出以来,抽水蓄能中长期发展规划为行业发展带来新机遇新挑战,第三版标准修订工作适时开展,区分功能定位、明确技术要求,积极响应了当前新能源和抽水蓄能行业高质量发展的要求。

多能互补发电系统故障识别与测距方法

随着大量新能源的接入,使得多端柔性直流系统(modular multilevel converter based multi-terminal direct current, MMC-MTDC)故障特征愈加复杂,快速准确的故障识别与测距是亟需解决的关键难题之一。为此,提出了一种风-光-储-蓄互补发电站经柔性直流输电外送系统故障识别与测距方法。首先,搭建风-光-储-蓄互补发电站经柔直外送系统,在此基础上,提出了一种Teager能量算子能量熵的新方法,利用测量点正负极Teager能量算子能量熵的比值构建故障选极及区段识别判据。接着,针对已识别的故障线路,提出变分模态分解(variational mode decomposition, VMD)与Teager能量算子(teager energy operator, TEO)相结合的故障测距方法。最后,利用PSCAD/EMTDC进行仿真,结果表明所提识别方法可以准确判断故障所在线路,所提测距方法能在故障发生2 ms时间窗内实现故障测距,误差率不超过2.55%,并具有较高的耐过渡电阻能力。

基于组合赋权-云模型的抽蓄电站高质量发展评价体系

为科学评价生产期抽蓄电站高质量发展现状、把握电站发展的薄弱环节、明确建设期及新投运电站发展方向,根据抽蓄电站定位及高质量发展内涵,经过2轮筛选,构建了包含服务电力系统稳定运行、经济、绿色、创新、共享5个一级指标以及18个二级指标的评价指标体系;选用层次分析法–决策实验分析方法确定指标权重,运用云模型评价各电站高质量发展等级。最后,选取A抽蓄电站为算例验证评价体系适用性。评价结果显示,该电站服务电力系统稳定运行、绿色和共享3个指标表现均为良好,经济和创新指标表现为中等,与电站实际运行情况相符合。该验证结果表明,采用上述方法构建的评价指标体系有很好的适用性。