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.

An optimal strategy for coordinating and dispatching “source-load” in power system based on multiple time scales

Due to the phenomenon of abandoning wind power and photo voltage(PV)power in the“Three Northern Areas”in China,this paper presents an optimal strategy for coordinating and dispatching“source-load”in power system based on multiple time scales.On the basis of the analysis of the uncertainty of wind power and PV power as well as the characteristics of load side resource dispatching,the optimal model of coordinating and dispatching“source-load”in power system based on multiple time scales is established.It can simultaneously and effectively dispatch conventional generators,wind plant,PV power station,pumped-storage power station and load side resources by optimally using three time scales:day-ahead,intra-day and real-time.According to the latest predicted information of wind power,PV power and load,the original generation schedule can be rolled and amended by using the corresponding time scale.The effectiveness of the model can be verified by a real system.The simulation results show that the proposed model can make full use of“source-load”resources to improve the ability to consume wind power and PV power of the grid-connected system.

蟠龙抽水蓄能电站地下厂房区初始地应力场反演

岩体初始地应力场是地下工程数值模拟与稳定分析的基础,是地下洞室群围岩变形的主要“荷载”。重庆蟠龙抽水蓄能电站地下厂房区域存在6层泥岩或粉砂质泥岩与泥质粉砂岩,抗压强度较低,属于软岩。结合实测地应力资料,采用有限元法结合多元线性回归分析,反演了工程区域的初始地应力场。结果表明,地应力反演计算值与实测值在量值大小和分布方向上吻合较好,通过反演得到的地应力场是合理可靠的。

蟠龙抽水蓄能电站月牙肋钢岔管结构与水力特性研究

对蟠龙抽水蓄能电站的埋藏式月牙肋钢岔管结构特性和水力特性进行了系统研究。通过对不同主、支管直径方案下的管壁应力、用钢量、水头损失等分析计算,得到岔管结构的受力状态和水力流态规律。研究结果表明,在正常运行情况下,管径越小岔管结构受力越有利,可有效地降低钢岔管制作安装的难度,但管内流速增大导致水头损失增加,从而降低电站发电效率。因此,管径选择时应综合考虑结构要求和水力要求,做到安全、经济、合理。

蟠龙抽水蓄能电站硐室围岩三轴试验及本构模型

利用岩石全自动伺服试验仪对重庆蟠龙抽水蓄能电站硐室围岩的砂岩试样开展了不同围压下的常规三轴压缩试验,进而构建了包含统一硬化/软化函数的弹塑性本构模型并进行了验证。试验结果表明,随着围压的增大,由原生缺陷闭合引起的初始非线性变形阶段逐渐减小,试样破坏时的峰值强度随围压增大而增大,由单轴压缩时的84.8 MPa增大到围压10 MPa时的168.5 MPa;峰值强度和围压之间呈现较好的线性关系,黏聚力和内摩擦角分别为15.2 MPa和52°。数值模拟与试验数据的比较表明,提出的弹塑性本构模型能够描述砂岩的主要力学现象,验证了该模型的可靠性。

考虑所有洞室开挖影响的蟠龙地下厂房结构特性分析

目前研究大型地下洞室群稳定问题所采用的计算模型为仅包含主厂房、主变室、母线洞及部分引水洞和尾水洞的三维简化模型,没有考虑其他洞室开挖对主厂房的影响,与实际工程不完全相符。为此,结合蟠龙水电站地下洞室群工程建立包含所有洞室的三维有限元模型及仅包含部分洞室的三维简化模型,采用三维非线性有限单元法研究洞室群在开挖过程中的变形规律和应力状态。结果表明:两种模型的应力、位移、塑性区的分布规律基本相似,包含所有洞室的三维有限元模型的计算结果普遍大于简化模型的计算结果,其中主厂房上游墙的水平位移差达19. 5%。从工程安全角度考虑,建议地下洞室群施工仿真分析选择包含所有洞室的三维有限元模型。

蟠龙抽水蓄能电站软硬间层地质条件下洞室群开挖对软岩的影响研究

蟠龙抽水蓄能电站地下厂房系统多跨越软硬间层的地质区,软岩地质区的洞室围岩稳定问题突出。结合工程建立了包含洞室群与软、硬岩层的三维整体有限元模型,采用三维非线性有限单元法,研究了洞室群开挖过程中软岩层的变形规律和应力状态。分析表明:开挖过程对软岩层扰动显著,开挖完成后,软岩层最大变形量在沿厂房轴线方向为24.3mm、垂直厂房轴线水平方向为50.2mm、铅直方向为35.5mm;厂房区出现一定范围的塑性区。从工程安全角度考虑,建议在地下厂房开挖前进行开挖过程对软岩层的影响分析。

蟠龙抽水蓄能电站地下厂房顶拱软岩分布与支护影响分析

支护是地下结构中不可或缺的部分,能提高围岩的稳定性,保证施工、运行的安全。针对蟠龙抽水蓄能电站地下厂房顶拱存在的软岩层,建立三维有限元模型,计算不同软岩厚度和地质缺陷的影响,分析顶拱围岩稳定性和支护效果。结果表明:地质条件越差时,顶拱位移越大,塑性区发育程度越大;支护作用下位移减小,塑性区发育程度降低,且地质条件越差时,支护效果越显著。

蟠龙抽水蓄能电站地下厂房区初始地应力场反演方法比较分析

岩体初始地应力场是地下工程数值模拟与稳定分析的必要条件,是地下洞室群围岩变形的主要“荷载”。根据重庆蟠龙抽水蓄能电站工程地下厂房区域的实测地应力资料,采用有限元法,结合多元回归方法、神经网络和遗传算法三种方法分别反演了工程区域的初始地应力场。结果表明:地应力反演计算值与实测值吻合较好,各方法计算结果比较接近,其中多元回归方法误差较小、计算时间较短。

软岩力学参数取值对洞室围岩变形应力及塑性区影响的敏感性分析

通过地质勘测、试验得到的围岩力学参数通常是一个区间值,计算时的不同取值对地下厂房位移、应力、塑性区有一定的影响。结合蟠龙抽水蓄能工程,建立了地下洞室群三维整体有限元模型,通过力学参数试验值的上下限取值,分析参数对主厂房位移、应力及塑性区的影响。结果表明,Ⅳ类、Ⅴ类变形弹性模量降低时,对位移影响最为显著,对应力与塑性区的影响相对较小;2种取值工况下,主厂房沿垂直厂房轴线方向的位移增幅达18%,应力和塑性区的变化在10%内。

Study on S-shaped characteristic of Francis reversible unit by on-site test and CFD simulation

The operation parameters （vibration, shaft displacement and pressure fluctuation） of No. 1 Francis reversible unit of Baoquan pumped-storage power station were measured on site in the no-load mode at net heads of 518.04, 522.01 and 530.38 m, re- spectively. The rotational speed fluctuations in the no-load mode at three net heads were beyond synchronization requirement with obvious S-shaped characteristic, and misaligned guide vanes （MGV） had to be put into use for synchronization. Further analysis demonstrated that the rotating frequency signal was generally dominant in vibration and shaft displacement mixing signal in the no-load mode, while the frequency domain was wide without an obvious main frequency in pressure fluctuation mixing signal. Besides, the SSTκ-ω turbulence model was adopted to simulate the four quadrant characteristic curves of Baoquan model pump-turbine at three gate openings, and the relative error between simulation results and model test data was within ±6%, indicating that the simulation method in this paper is feasible and S-shaped characteristic of the pump-turbine can be simulated with CFD method.