scholarly journals Probabilistic Model for Real-Time Flood Operation of a Dam Based on a Deterministic Optimization Model

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3206
Author(s):  
Víctor Cuevas-Velásquez ◽  
Alvaro Sordo-Ward ◽  
Jaime H. García-Palacios ◽  
Paola Bianucci ◽  
Luis Garrote
Keyword(s):  
Real Time ◽  
Optimization Model ◽  
Flood Control ◽  
Evaluation Method ◽  
Risk Index ◽  
Mixed Integer ◽  
Global Risk ◽  
Case Based Learning ◽  
Milp Model ◽  
Conventional Models

This paper presents a real-time flood control model for dams with gate-controlled spillways that brings together the advantages of an optimization model based on mixed integer linear programming (MILP) and a case-based learning scheme using Bayesian Networks (BNets). A BNet model was designed to reproduce the causal relationship between inflows, outflows and reservoir storage. The model was trained with synthetic events generated with the use of the MILP model. The BNet model produces a probabilistic description of recommended dam outflows over a time horizon of 1 to 5 h for the Talave reservoir in Spain. The results of implementing the BNet recommendation were compared against the results obtained while applying two conventional models: the MILP model, which assumes full knowledge of the inflow hydrograph, and the Volumetric Evaluation Method (VEM), a method widely used in Spain that works in real-time, but without any knowledge of future inflows. In order to compare the results of the three methods, the global risk index (Ir) was computed for each method, based on the simulated behavior for an ensemble of hydrograph inflows. The Ir values associated to the 2 h-forecast BNet model are lower than those obtained for VEM, which suggests improvement over standard practice. In conclusion, the BNet arises as a suitable and efficient model to support dam operators for the decision making process during flood events.

scholarly journals Hydrological Risk Analysis of Dams: The Influence of Initial Reservoir Level Conditions

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 461 ◽  
Author(s):  
Ivan Gabriel-Martin ◽  
Alvaro Sordo-Ward ◽  
Luis Garrote ◽  
Isabel Granados
Keyword(s):  
Risk Analysis ◽  
Flood Control ◽  
Evaluation Method ◽  
Risk Index ◽  
Flood Routing ◽  
Dam Safety ◽  
Global Risk ◽  
Reservoir Level ◽  
Design Flood ◽  
Relevant Variable

In this paper, we present a method to assess the influence of the initial reservoir level in hydrological dam safety and risk analysis. Traditionally, in professional practice, the procedures applied are basically deterministic. Several physical processes are defined deterministically, according to the criteria of the designer (usually in the conservative side), although there is a high degree of uncertainty regarding these processes. A relevant variable is the reservoir level considered at the beginning of flood events. Hydrological dam safety assessment methods traditionally assume that the reservoir is initially full when it receives the design flood, thus, staying in the conservative side when designing a new dam. However, the distribution of reservoir levels at the beginning of flood episodes takes more importance for evaluating the real risk for the dams in operation. We analyzed three different scenarios—initial reservoir level equal to maximum normal level, equal to a maximum conservation level, and following the probability distribution from the historical records. To do so, we presented a method applied to a gated-spillway dam located in the Tagus river basin. A set of 100,000 inflow hydrographs was generated through a Monte Carlo procedure, by reproducing the statistics of the main observed hydrograph characteristics—peak flow, volume, and duration. The set of 100,000 hydrographs was routed through the reservoir applying the Volumetric Evaluation Method as a flood control strategy. In order to compare the three scenarios, we applied an economic global risk index. The index combines the hydrological risk for the dam, linked to the maximum water level reached in the reservoir, during the flood routing, and the flood risk in the downstream river reach, linked to the discharge releases from the dam. The results showed the importance of accounting for the fluctuation of initial reservoir levels, for assessing the risk related to hydrological dam safety. Furthermore, a procedure to quantify the uncertainty associated with the effects of initial reservoir level on hydrological dam safety, has been proposed.

scholarly journals Spillways Scheduling for Flood Control of Three Gorges Reservoir Using Mixed Integer Linear Programming Model

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Maoyuan Feng ◽  
Pan Liu
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Three Gorges Reservoir ◽  
Flood Control ◽  
Mixed Integer ◽  
Piecewise Linear Approximation ◽  
Three Gorges ◽  
Reservoir Storage ◽  
Milp Model

This study proposes a mixed integer linear programming (MILP) model to optimize the spillways scheduling for reservoir flood control. Unlike the conventional reservoir operation model, the proposed MILP model specifies the spillways status (including the number of spillways to be open and the degree of the spillway opened) instead of reservoir release, since the release is actually controlled by using the spillway. The piecewise linear approximation is used to formulate the relationship between the reservoir storage and water release for a spillway, which should be open/closed with a status depicted by a binary variable. The control order and symmetry rules of spillways are described and incorporated into the constraints for meeting the practical demand. Thus, a MILP model is set up to minimize the maximum reservoir storage. The General Algebraic Modeling System (GAMS) and IBM ILOG CPLEX Optimization Studio (CPLEX) software are used to find the optimal solution for the proposed MILP model. The China’s Three Gorges Reservoir, whose spillways are of five types with the total number of 80, is selected as the case study. It is shown that the proposed model decreases the flood risk compared with the conventional operation and makes the operation more practical by specifying the spillways status directly.

scholarly journals Multi-Ship Collision Avoidance Decision-Making Based on Collision Risk Index

2020 ◽  
Vol 8 (9) ◽  
pp. 640
Author(s):  
Yingjun Hu ◽  
Anmin Zhang ◽  
Wuliu Tian ◽  
Jinfen Zhang ◽  
Zebei Hou
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Risk Analysis ◽  
Real Time ◽  
Collision Avoidance ◽  
Evaluation Method ◽  
Risk Index ◽  
Collision Risk ◽  
Ship Collision ◽  
Risk Thresholds

Most maritime accidents are caused by human errors or failures. Providing early warning and decision support to the officer on watch (OOW) is one of the primary issues to reduce such errors and failures. In this paper, a quantitative real-time multi-ship collision risk analysis and collision avoidance decision-making model is proposed. Firstly, a multi-ship real-time collision risk analysis system was established under the overall requirements of the International Code for Collision Avoidance at Sea (COLREGs) and good seamanship, based on five collision risk influencing factors. Then, the fuzzy logic method is used to calculate the collision risk and analyze these elements in real time. Finally, decisions on changing course or changing speed are made to avoid collision. The results of collision avoidance decisions made at different collision risk thresholds are compared in a series of simulations. The results reflect that the multi-ship collision avoidance decision problem can be well-resolved using the proposed multi-ship collision risk evaluation method. In particular, the model can also make correct decisions when the collision risk thresholds of ships in the same scenario are different. The model can provide a good collision risk warning and decision support for the OOW in real-time mode.

Long-Term Multi-Objective Optimization Dispatch and its Evaluation in Wind Integrated Power Systems

2013 ◽  
Vol 732-733 ◽  
pp. 1033-1037 ◽  
Author(s):  
Ke Wang ◽  
Da Hai You ◽  
Kai Pan
Keyword(s):  
Optimization Model ◽  
Evaluation System ◽  
Evaluation Method ◽  
Electric Power Industry ◽  
Wind Farms ◽  
Fuzzy Comprehensive Evaluation ◽  
Mixed Integer ◽  
Piecewise Linearization ◽  
Multi Objective

With energy saving and emission reduction paid more and more attention in electric power industry, long-term optimization dispatch in wind-integrated power system must take into consideration many inconsistent factors. In this paper on the basis of comprehensive consideration of coal consumption, emissions, openness and impartiality, a long-term multi-objective fuzzy optimization dispatch model is established. The model can optimize jointly generation maintenance scheduling, unit commitment and power output. After piecewise linearization of the objectives and the constraints, the optimization model is converted to a mixed integer linear programming (MILP) problem. An efficient optimization software CPLEX is employed to solve the problem. In order to analyze and compare different generation scheduling, a series of indices and fuzzy comprehensive evaluation method are utilized to evaluate the optimal results obtained. The proposed model is tested in IEEE 118-bus system incorporating three wind farms. The results show that the optimization model and the evaluation system built are effective and feasible.

scholarly journals Stochastic Assessment of the Influence of Reservoir Operation in Hydrological Dam Safety through Risk Indexes

Proceedings ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 12
Author(s):  
Ivan Gabriel-Martin ◽  
Alvaro Sordo-Ward ◽  
Luis Garrote ◽  
Isabel Granados
Keyword(s):  
Probability Distribution ◽  
Flood Risk ◽  
Management Strategy ◽  
Flood Control ◽  
Evaluation Method ◽  
Risk Index ◽  
Reservoir Management ◽  
Dam Safety ◽  
Reservoir Level ◽  
Design Flood

Hydrological dam safety assessment methods traditionally assume that the reservoir is full while it receives the design flood. In practice, reservoir management strategy determines the probability distribution of reservoir levels at the beginning of flood episodes. In this study, we present a method to economically assess the influence of reservoir management strategy on hydrological dam safety and downstream flood risk. The method was applied to a gated spillway dam located in the Tagus River basin. A set of 100,000 inflow hydrographs was generated through a Monte Carlo procedure, reproducing the observed statistics of main hydrograph characteristics: peak flow, volume, and duration. The set of 100,000 hydrographs was routed through the reservoir applying the volumetric evaluation method as a flood control strategy. Three different scenarios were studied: Initial reservoir level equal to maximum normal level, equal to a maximum conservation level, and following the probability distribution of initial reservoir levels. In order to evaluate economically the influence of initial variable reservoir level and compare the three scenarios, a global risk index was applied. The index combines the hydrological risk for the dam, linked to the maximum water level experienced in the reservoir while the flood is routed, and the flood risk in the downstream river reach, linked to the discharge releases from the dam. The results highlighted the importance of considering the fluctuation of initial reservoir level for assessing the risk related to hydrological dam safety.

scholarly journals Real-time reservoir flood control operation enhanced by data assimilation

2020 ◽  
Author(s):  
Jingwen Zhang ◽  
Ximing Cai ◽  
Xiaohui Lei ◽  
Pan Liu ◽  
Hao Wang
Keyword(s):  
Data Assimilation ◽  
Real Time ◽  
Real World ◽  
Flood Risk ◽  
Optimization Model ◽  
Reservoir Operation ◽  
Flood Control ◽  
Interactive Method ◽  
Operation Conditions ◽  
Time Period

Abstract. Real world reservoir operations are usually not fully automatic based on computer models; instead, reservoir operators conduct the operations based on their experiences, professional justification, as well as modeling support for some cases due to unavoidable gap between computer modeling and real world reservoir operation conditions. In this paper, we propose a human-machine interactive method, namely Real-time Optimization Model Enhanced by Data Assimilation (ROMEDA) for reservoirs which have complex storage and stage relations (e.g. long and narrow reservoirs). The system is composed of 1) an optimization model to search for optimal releases, 2) reservoir operators’ choices based on their experiences, knowledge, and behaviors, and 3) a reservoir storage-stage simulation and data assimilation schedule to update the storage based on real-time reservoir stage observations. For every time period and based on the updated storage, ROMEDA provides optimal releases as recommendations, actual releases made by operators, as well as a warning of flood risk when the storage exceeds a threshold level. ROMEDA does not assume that operators strictly accept the recommendations, and storage will be updated based on actual release at each time period. Via a case study on-channel reservoir, it is found that for both small and large flood events, ROMEDA, which integrates the advantages of both machine and human, shows better performance on flood risk mitigation and water use (hydropower) benefit than the case with historical operation records (HOR) or optimization with single/multi-objective. ROMEDA is one of the first attempts of a human-machine interactive method for online use of an optimization model for real-time reservoir operation based on integrated modeling, observation, and operators’ choice.

scholarly journals A Robust Optimization Model to the Day-Ahead Operation of an Electric Vehicle Aggregator Providing Reliable Reserve

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7456
Author(s):  
Antonio Jiménez-Marín ◽  
Juan Pérez-Ruiz
Keyword(s):  
Robust Optimization ◽  
Real Time ◽  
Electric Vehicle ◽  
Optimization Model ◽  
Linear Problem ◽  
The Other ◽  
Mixed Integer ◽  
Robust Approach ◽  
Proposed Model

This paper presents a robust optimization model to find out the day-ahead energy and reserve to be scheduled by an electric vehicle (EV) aggregator. Energy can be purchased from, and injected to, the distribution network, while upward and downward reserves can be also provided by the EV aggregator. Although it is an economically driven model, the focus of this work relies on the actual availability of the scheduled reserves in a future real-time. To this end, two main features stand out: on one hand, the uncertainty regarding the EV driven pattern is modeled through a robust approach and, on the other hand, a set of non-anticipativity constraints are included to prevent from unavailable future states. The proposed model is posed as a mixed-integer robust linear problem in which binary variables are used to consider the charging, discharging or idle status of the EV aggregator. Results over a 24-h case study show the capability of the proposed model.

Research on Oil Depot Safety Evaluation Based on Dow Chemical Fire and Explosion Index Assessment Method

2013 ◽  
Vol 748 ◽  
pp. 1256-1261
Author(s):  
Shou Hui He ◽  
Han Hua Zhu ◽  
Shi Dong Fan ◽  
Quan Wen
Keyword(s):  
Production Management ◽  
Evaluation Method ◽  
Risk Index ◽  
Safety Evaluation ◽  
Assessment Method ◽  
Theoretical Ground ◽  
Potential Hazard ◽  
Process Unit ◽  
Safety Production ◽  
Fire And Explosion

At the present time, the Dow Chemical Fire and Explosion Index (F&EI) is a kind of risk index evaluation method that is comprehensively used in evaluating potential hazard, area of exposure, expected losses in case of fire and explosion, etc. As the research object to oil depot storage tank area, this article ultimately confirms establishing appropriate pattern of process unit as well as reasonable safety precautions compensating method, in order to insure the reasonableness of evaluating result, by means of selecting process unit, confirming material factor and compensating safety precautions, using F&EI method. This can provide the basis for theoretical ground in aspect of oil depot development and safety production management.

Sign in / Sign up

Export Citation Format

Share Document