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 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 Multi-objective optimization of solar thermal photovoltaic hybrid power generation system based on NSGA-II algorithm

2021 ◽  
Vol 336 ◽  
pp. 02022
Author(s):  
Liang Meng ◽  
Wen Zhou ◽  
Yang Li ◽  
Zhibin Liu ◽  
Yajing Liu
Keyword(s):  
Power Generation ◽  
Optimization Problems ◽  
Optimal Solution ◽  
Solar Thermal ◽  
Multi Objective Optimization ◽  
Generation System ◽  
Nsga Ii ◽  
Multi Objective ◽  
Hybrid Power ◽  
Power Generation System

In this paper, NSGA-Ⅱ is used to realize the dual-objective optimization and three-objective optimization of the solar-thermal photovoltaic hybrid power generation system; Compared with the optimal solution set of three-objective optimization, optimization based on technical and economic evaluation indicators belongs to the category of multi-objective optimization. It can be considered that NSGA-Ⅱ is very suitable for multi-objective optimization of solar-thermal photovoltaic hybrid power generation system and other similar multi-objective optimization problems.

scholarly journals Multi Objective for PMU Placement in Compressed Distribution Network Considering Cost and Accuracy of State Estimation

2019 ◽  
Vol 9 (7) ◽  
pp. 1515 ◽  
Author(s):  
Kong ◽  
Wang ◽  
Yuan ◽  
Yu
Keyword(s):  
State Estimation ◽  
Estimation Error ◽  
Distribution Network ◽  
Measurement Data ◽  
Optimal Solution ◽  
Pareto Set ◽  
Measurement Unit ◽  
Nsga Ii ◽  
Multi Objective ◽  
Pmu Placement

A phasor measurement unit (PMU) can provide phasor measurements to the distribution network to improve observability. Based on pre-configuration and existing measurements, a network compression method is proposed to reduce PMU candidate locations. Taking the minimum number of PMUs and the lowest state estimation error as the objective functions and taking full observability of distribution network as the constraint, a multi objective model of optimal PMU placement (OPP) is proposed. A hybrid state estimator based on supervisory control and data acquisition (SCADA) and PMU measurements is proposed. To reduce the number of PMUs required for full observability, SCADA measurement data are also considered into the constraint by update and equivalent. In addition, a non-dominated sorting genetic algorithm-II (NSGA-II) is applied to solve the model to get the Pareto set. Finally, the optimal solution is selected from the Pareto set by the technique for order preference by similarity to ideal solution (TOPSIS). The effectiveness of the proposed method is verified by IEEE standard bus systems.

Multi-Objective Optimal Mechanical Power for Turbine of River Current Power Generation Using Fuzzy Dominant Directed-Graph Method

2013 ◽  
Vol 284-287 ◽  
pp. 839-843
Author(s):  
Jian Long Kuo ◽  
Kai Lun Chao
Keyword(s):  
Power Generation ◽  
Taguchi Method ◽  
Output Power ◽  
Directed Graph ◽  
Optimal Solution ◽  
Generation System ◽  
Multi Objective ◽  
Optimal Output ◽  
Power Generation System ◽  
River Current

Abstract. The fuzzy dominant directed graph (fuzzy DDG) method is proposed in this paper to solve the multi-objective optimal mechanical turbine power of river current (RC) power generation system. Recently, there is great potential for the RC power generation system in renewable energy. The experimental Taguchi method is used to find the optimal solution for the power generation system. The optimization problem for the AC generator in RC power generation system is studied. The optimal output power with respect to three selected control factors is studied. By using Taguchi method, five cases are discussed. The testing case is the optimal output power problem. It is convinced that this method is applicable and easy to find the optimal solution quickly.

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.

MULTI-OBJECTIVE OPTIMAL MECHANICAL POWER FOR TURBINE OF RIVER CURRENT POWER GENERATION USING FUZZY DOMINANT DIRECTED-GRAPH METHOD

2013 ◽  
Vol 37 (3) ◽  
pp. 797-805
Author(s):  
Jian-Long Kuo ◽  
Kai-Lun Chao
Keyword(s):  
Power Generation ◽  
Directed Graph ◽  
Optimal Solution ◽  
Experimental Results ◽  
Generation System ◽  
Graph Method ◽  
Multi Objective ◽  
Power Generation System ◽  
Testing Case ◽  
River Current

The fuzzy dominant directed graph (fuzzy DDG) method is proposed in this paper to realize the multi-objective optimal mechanical turbine power of a river current (RC) power generation system. The testing case illustrates the problem with vertex S/N ratio values included. Fuzzy potential values are derived. The experimental results are provided to verify the validity of the fuzzy-DDG method. It is clear that this method is applicable; it easily and quickly finds the optimal solution.

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