scholarly journals Upper Limit and Power Generation Loss of Water Supplement from Cascade Hydropower Stations to Downstream Under Lancang-Mekong Cooperation

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2826
Author(s):  
Jiahui Deng ◽  
Yu Li ◽  
Wei Ding ◽  
Bingyao Zhang ◽  
Bo Xu ◽  
...  
Keyword(s):  
Power Generation ◽  
Water Resources ◽  
Optimization Problem ◽  
Optimization Method ◽  
Joint Optimization ◽  
Cross Border ◽  
Upper Limit ◽  
Cascade Hydropower Stations ◽  
Firm Power ◽  
Hydropower Stations

In cross-border water supplement cooperation, the supplement water discharged from upstream hydropower stations is the key to improving downstream benefits, but will lead to upstream power generation loss, so the upstream hydropower stations have to be aware of how much water they can offer and how much power they will lose to make the water supplement cooperation more reasonable. Therefore, this study puts forward a model to calculate the upper limit flow of water supplement of cascade hydropower stations under firm power constraints and water level constraints and proposes a new optimization method called the “collaborative-independent” joint optimization method to calculate the power generation loss under water supplement constraints. The results show that the upper limit flow will increase with the increase of annual inflow, and the uncertainty of the distribution of inflow in the year will also affect the upper limit flow: the larger the proportion of non-flood season inflow, the higher the upper limit flow. In normal and wet years, delaying water supplement time can significantly increase the upper limit flow by about 5% per month. Additionally, the “collaborative-independent” joint optimization method newly proposed in this paper can significantly improve the local optimization problem compared to the traditional optimization method. The power generation loss increases with the increase of water supplement flow, and delaying water supplement time can significantly reduce the power generation loss. The results of this paper can provide essential data support for future water resources cooperation negotiations in the Lancang-Mekong river basin to promote efficient and orderly water resources cooperation in the basin.

scholarly journals Copula-Based Research on the Multi-Objective Competition Mechanism in Cascade Reservoirs Optimal Operation

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 995 ◽  
Author(s):  
Menglong Zhao ◽  
Shengzhi Huang ◽  
Qiang Huang ◽  
Hao Wang ◽  
Guoyong Leng ◽  
...  
Keyword(s):  
Power Generation ◽  
Irrigation Water ◽  
Optimal Solution ◽  
Water Shortage ◽  
Pareto Set ◽  
The Other ◽  
Competition Mechanism ◽  
Multi Objective ◽  
Cascade Hydropower Stations ◽  
Hydropower Stations

Water resources systems are often characterized by multiple objectives. Typically, there is no single optimal solution which can simultaneously satisfy all the objectives but rather a set of technologically efficient non-inferior or Pareto optimal solutions exists. Another point regarding multi-objective optimization is that interdependence and contradictions are common among one or more objectives. Therefore, understanding the competition mechanism of the multiple objectives plays a significant role in achieving an optimal solution. This study examines cascade reservoirs in the Heihe River Basin of China, with a focus on exploring the multi-objective competition mechanism among irrigation water shortage, ecological water shortage and the power generation of cascade hydropower stations. Our results can be summarized as follows: (1) the three-dimensional and two-dimensional spatial distributions of a Pareto set reveal that these three objectives, that is, irrigation water shortage, ecological water shortage and power generation of cascade hydropower stations cannot reach the theoretical optimal solution at the same time, implying the existence of mutual restrictions; (2) to avoid subjectivity in choosing limited representative solutions from the Pareto set, the long series of non-inferior solutions are adopted to study the competition mechanism. The premise of sufficient optimization suggests a macro-rule of ‘one falls and another rises,’ that is, when one objective value is inferior, the other two objectives show stronger and superior correlation; (3) the joint copula function of two variables is firstly employed to explore the multi-objective competition mechanism in this study. It is found that the competition between power generation and the other objectives is minimal. Furthermore, the recommended annual average water shortage are 1492 × 104 m3 for irrigation and 4951 × 104 m3 for ecological, respectively. This study is expected to provide a foundation for selective preference of a Pareto set and insights for other multi-objective research.

scholarly journals A rapid solution adjustment strategy in solving Long-term scheduling of large cascade hydropower stations

2018 ◽  
Vol 246 ◽  
pp. 01123
Author(s):  
Chao Wang ◽  
Liang Ji ◽  
Peibing Song ◽  
Xin Hu ◽  
Jiahui Sun
Keyword(s):  
Power Generation ◽  
Linear Optimization ◽  
Electrical Power ◽  
Optimal Operation ◽  
Electrical Power System ◽  
Adjustment Strategy ◽  
Cascade Hydropower Stations ◽  
Rapid Adjustment ◽  
Hydropower Stations

Due to the great potential of large cascade hydropower stations on power generation, long-term scheduling of large cascade hydropower stations (LSLCHS) plays an important role in electrical power system. As more and more concentrations focused on the optimal operation of large cascade hydropower stations, the LSLCHS has been taken into a multi-dimensional, non-convex and non-linear optimization problem due to its complicated hydraulic connection relationships and varieties of complex constraints with considering its power generation, shipping and ecological characteristics. In order to solve this problem, a strategy of solution rapid adjustment regarding the principle of monotone principle is proposed accordingly. The simulation results show that the proposed method is an efficient for solving joint optimization dispatch model of cascade hydropower stations with fast convergent rate, strong robustness.

scholarly journals Influence of Power Operations of Cascade Hydropower Stations under Climate Change and Human Activities and Revised Optimal Operation Strategies: A Case study in the Upper Han River, China

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 895 ◽  
Author(s):  
Wu ◽  
Bai ◽  
Huang ◽  
Zhang ◽  
Mu
Keyword(s):  
Climate Change ◽  
Power Generation ◽  
Simulation Model ◽  
Human Activities ◽  
Optimal Operation ◽  
Han River ◽  
Power Stations ◽  
Runoff Series ◽  
Cascade Hydropower Stations ◽  
Hydropower Stations

Climate change and human activities are two driving factors that affect the hydrological cycle of watersheds and water resource evolution. As a pivotal input to hydropower stations, changes in runoff processes may reduce the effectiveness of existing operation procedures. Therefore, it is important to analyze the influences of cascade hydropower stations under climate change and human activities and to propose revised optimal operation strategies. For the present study, three runoff series conditions including: Initial runoff, affected by only climate change, and affected by both climate change and human activities are examined by a simulation model to analyze the influence on power generation with four schemes. Additionally, an optimal operation model of cascade power stations is proposed based on the simulation model to generate single and joint optimal operation charts for future hydrological scenarios. The paper also proposes to change human activities based on optimizing operation rules to reduce its influence on downstream power stations. This procedure is theoretically applied and varied for three power stations in the upper Han River, China. The results show that the influence of climate change is greater than that of human activities in that power generation decreased by 17.95% and 12.83%, respectively, whereas combined, there is a reduction of 25.71%. Under existing hydrological conditions, the modified single and joint operation charts would increase power generation by about 32 million and 47 million kWh. Furthermore, after optimizing the upstream project, the abandoned water and power generation of these cascade power stations would reduce by 150 million m3 and 5 million kWh, respectively. This study has practical significance for the efficient operation of cascade hydropower stations and is helpful for developing reservoir operation theory under changing environments.

scholarly journals Joint optimization of cascades in Yalong River and the middle and downstream of Jinsha River

2018 ◽  
Vol 246 ◽  
pp. 01104 ◽  
Author(s):  
Hairong Zhang ◽  
Peng Li ◽  
Yufeng Ren ◽  
Zhiming Liang ◽  
Yufan Chen ◽  
...  
Keyword(s):  
Power Generation ◽  
Large Scale ◽  
Optimization Method ◽  
Research Area ◽  
Optimal Scheduling ◽  
Joint Optimization ◽  
Total Power ◽  
Jinsha River ◽  
Hydropower System ◽  
Yalong River

The main tributaries of the upper reaches of the Yangtze River are not only the strategic base for China’s water resources, but also an important hydropower base for the “West-East Power Transmission Strategy”. With the completion of these reservoir groups, a large-scale mixed reservoir system across the different basins has been formed, which makes the requirements for joint optimization and scheduling of large-scale hydropower system getting higher and higher. This paper focuses on the key problems faced by the joint optimization of large-scale hydropower system in the basin. Taking the Yalong River and the middle and downstream of the Jinsha River as the research area, the hybrid optimization method is introduced herein to solve the joint optimal scheduling model. The results reveal that the power generation by joint optimal scheduling is much more than separately scheduling, and the total power generation increased by 2.84% on average. As Mid-Jinsha cascade and Yalong River cascade has a 690 million kW·h and 190 million kW·h decrease in power generation respectively, the downstream Jinsha River cascade has a power generation increase of 4.31 billion kW·h.

scholarly journals The optimal equilibrium operation between power generation and ecology of Qingjiang cascade hydropower stations

2018 ◽  
Vol 246 ◽  
pp. 01063
Author(s):  
Yinghai Li ◽  
Wei Lin ◽  
Jiali Guo ◽  
Qingqing Xia ◽  
Wang Li
Keyword(s):  
Power Generation ◽  
Scientific Method ◽  
River System ◽  
Water Shortage ◽  
Optimal Operation ◽  
Complex Model ◽  
Evaluation Index System ◽  
Cascade Hydropower Stations ◽  
Frequency Calculation ◽  
Hydropower Stations

Ecological operation of cascade hydropower stations is one of the most important methods for the ecological restoration of a river system. In order to balance the benefits between power generation and ecology of Qingjiang cascade hydropower station, an optimal equilibrium operation method is proposed in this paper. Firstly, the range of ecological flow of the Qingjiang cascade is calculated by using ten-day frequency calculation method. Secondly, an optimal equilibrium operation model by considering the balance between power generation and ecology is established. And then, in order to solve this complex model, a particle swarm optimization based model solution method is proposed, and the evaluation index system of operation schemes is established. Finally, through operation calculation in 2008-2010 years, the results show that compared with the operation scheme considering only power generation benefit, the optimal equilibrium operation scheme increases the runoff ecological dispersion coefficient by 6.90%，reduces the cascade ecological overflow by 7.739 billion m3 and the cascade ecological water shortage by 130 million m3, while the cascade power generation decreases slightly by 1.83%. This study provides an effective scientific method for the optimal operation of Qingjiang cascade under the background of Yangtze River protection.

scholarly journals Research on Short-term Multi-objective Optimization Scheduling oriented Peak Regulation of Power Network

2018 ◽  
Vol 246 ◽  
pp. 01026
Author(s):  
Mo Li ◽  
Yongqiang Wang ◽  
Xinwen Gao ◽  
Shen Qin
Keyword(s):  
Power Generation ◽  
Power Grid ◽  
Multi Objective Optimization ◽  
Short Term ◽  
Multi Objective ◽  
Generation Planning ◽  
Power Generation Planning ◽  
Cascade Hydropower Stations ◽  
Hydropower Stations ◽  
Optimization Scheduling

With the succession of river basins and inter-basin hydropower stations, the joint optimal operation of cascade hydropower stations in the river basin has large-scale, nonlinear, strong coupling, and multi-target characteristics, and must consider the effects of hydrometeorology, water demand, and power grid security. Focusing on the preparation of short-term power generation plans for cascade hydropower stations on the Qingjiang River, a comprehensive multi-objetive power generation planning model with the largest total power generation and the least load variance on the power grid is established. Based on the constraint processing method of multi-objective optimization scheduling in long-term, the optimal flow distribution technology is adopted to improve the accuracy of power generation planning. The above model is solved by using SMPSO. The results show that the improved algorithm can effectively overcome the shortcomings of slow convergence speed and easy convergence to local optimum. It can improve the power generation efficiency of the whole cascade while responding to the peaking demand of the power grid and provide a new solution to the short-term power generation planning ideas.

scholarly journals Study on Optimal Operation of Hydropower Station Group Based on New Electricity Reform and Deviation Assessment

2018 ◽  
Vol 246 ◽  
pp. 02018
Author(s):  
Yanmei Zhu ◽  
Shijun Chen ◽  
Weibin Huang ◽  
Diya Xie ◽  
Wang Li ◽  
...  
Keyword(s):  
Power Generation ◽  
Optimal Operation ◽  
System Reform ◽  
Power Generators ◽  
Electricity System ◽  
Cascade Hydropower Stations ◽  
Market Rules ◽  
Hydropower Scheduling ◽  
Station Group ◽  
Hydropower Stations

The new electricity system reform has brought power generation companies into the market, and the scheduling target of cascade hydropower stations has been transformed from maximizing power generation to maximizing revenue. Market rules require hydropower generators to pay assessment fees for the power generation deviation. Therefore, in order to obtain the desired revenue, power generators should not only obtain more power generation indicators and higher power prices, but also control the power generation deviation and avoid being assessed. In response to the current market environment, the new requirements of the new electricity system reform for hydropower scheduling were analyzed. And based on regional market rules, a scheduling model for cascade hydropower stations with the goal of minimizing generation deviation was established, taking the example of eight cascade hydropower stations in the downstream of Dadu River in Sichuan province as an example, the effectiveness and applicability of the model were verified. The results show that the deviation in each period can be controlled within 1% and meet the basic requirements of market rules.

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