A new long-term hydro production scheduling method for maximizingthe profit of hydroelectric systems

This paper presents a new long-term hydrothermal production scheduling method. The proposed method maximizes the profit of hydroelectric plants, based on the monthly energy requirement of the system, instead of minimizing the production cost of thermal units. It is shown that different forms of composite thermal marginal costs will lead to the same hydro production schedule. Thus a linear marginal cost, the simplest form, is sufficient for long-term hydrothermal scheduling. A linear hydro marginal profit is also sufficient for this purpose. An immediate conclusion is that an actual composite thermal cost function, which is complicated by thermal unit availability, may not be needed for the long-term optimal hydrothermal scheduling. Due to this simplification, traditional long and mid-term hydrothermal scheduling, a complicated problem, becomes easier to solve. The method can be used by the owners of independent hydro plants in a region for long-term hydroelectric scheduling under both deregulation and competition. A case study shows that the model allocates successfully and efficiently the hydroelectric resources to peak demand periods with negligible computation time     

梯级水电站联合优化发电调度

梯级水电站联合发电调度的优化模型的确定在整个电网经济、安全运行中起着非常重要的作用。文中提出一种新的梯级水电站群联合发电优化调度的调度准则——以单位水体发电电价最高优先发电,在此基础上建立梯级水电站群联合发电优化调度模型及其评价方法。首先建立基于四层水体的水库能的水电站发电模型,在此基础上提出单位水体发电电价的概念。建立优化调度模型时,将电力系统中的负荷变化和在电力市场机制下分时上网电价的影响因素考虑在内。该模型能较为客观地反映梯级水电站运行情况,能给系统调度员做出最佳调度决策提供一定的依据。优化仿真计算结果证明该调度准则具有可行性和适用性。     

A short term hydrothermal scheduling approach for dominantly hydrosystems

A short-term hydrothermal scheduling approach is presented for predominantly hydroelectric systems. The model takes into account both the operating hydroelectric system and the electric transmission network constraints. The model consists of a simulation of the hydraulic system with the discharge decisions given by an optimal DC power flow algorithm. The release targets of the reservoirs, established by long-term operational planning, are enforced by a dual Lagrangean approach that fixes a penalty for the use of water in the reservoirs. Two illustrative examples have been solved in order to evaluate the efficiency of the approach     

独立发电企业水火协调优化运行研究综述

介绍了在电力市场环境中,当独立发电企业同时拥有水电和火电的情况下,国内外关于研究合理安排水火电发电计划的理论和方法,从而使发电企业运行总成本最少。同时,详细阐述了各种方法取得的进展和以后的研究方向。     

水火电力系统负荷分配的节能模型

基于二次曲线型三级水库水体分析了三级水体对水电站的机组所产生电能及水轮发电机组所产生的电功率。分析了有功功率负荷在水电厂和火电厂之间的最优分配问题,建立了水电站水耗量最小化的水火电力系统联合负荷分配的节能优化模型。利用水煤能源换算系数,提供优化的方法确定水电机组的耗水量和火电机组的耗煤量,从而实现水电机组节水发电、火电机组节煤发电的目的;采取水煤能源换算系数负荷分配的节能效果不一样,水煤能源换算系数的数值越小,分配给水电的功率就越多,火电发出的功率相应的减少,煤耗量就越少,节能效果越显著。给出了一个计算实例,验证了所提出模型的适用性。     

A noise annealing neural network for hydroelectric generationscheduling with pumped-storage units

A new approach based on neural network is proposed for the hydroelectric generation scheduling with pumped-storage units at Taiwan power system. The purpose of hydroelectric generation scheduling is to determine the optimal amounts of generated powers for the hydro units in the system. To achieve an economical dispatching schedule for the hydro units including two large pumped-storage plants, a neural network is employed to reach a schedule in which total fuel cost of the thermal units over the study period is minimized. The neural network model presented can solve nonlinear constrained optimization problems with continuous decision variables. Incorporating the noise annealing concepts, the model is able to produce such a solution which is the global optimum of the original problem with probability close to 1. The proposed approach is applied to hydroelectric generation scheduling of Taiwan power system. It is concluded from the results that the proposed approach is very effective in reaching proper hydro generation schedules     

Parameterisation effect on the behaviour of a head-dependent hydro chain using a nonlinear model

This paper is on the problem of short-term hydro scheduling (STHS), particularly concerning a head-dependent hydro chain. We use a method based on nonlinear programming (NLP), namely quadratic programming, to consider hydroelectric power generation a function of water discharge and of the head. The method has been applied successfully to solve a test case based on a realistic cascaded hydro system with a negligible computational time requirement and is also applied to show that the role played by reservoirs in the hydro chain do not depend only on their relative position. As a new contribution to earlier studies, which presented reservoir operation rules mainly for medium and long-term planning procedures, we show that the physical data defining hydro chain parameters used in the nonlinear model have an effect on the STHS, implying different optimal storage trajectories for the reservoirs accordingly not only with their position in the hydro chain but also with the new parameterisation defining the data for the hydro system. Moreover, considering head dependency in the hydroelectric power generation, usually neglected for hydro plants with a large storage capacity, provides a better short-term management of the conversion of the potential energy available in the reservoirs into electric energy, which represents a major advantage for the hydroelectric utilities in a competitive electricity market.     

计及不确定因素的梯级水电站短期优化调度

以一定时期内期望发电效益最大化为目标,采用马尔可夫链对梯级水电站机组未来调度时段的预想故障及上网电价进行概率预测,构建了一种新的梯级水电站短期概率优化调度的模型,并且采用服从正态分布的负荷波动来分析时变负荷对优化调度的影响.该模型全面考虑了梯级水电站蓄水量、弃水量、水位、发电引用流量等约束条件,实现了机组运行状态概率预...     

水火电力系统多目标优化调度

水火电力系统多目标优化调度模型的确定在整个电网经济、安全运行中起着非常重要的作用。本文首先分析了大型水库的3种水能形式,建立了水电站发电模型,并在此基础上提出了耗水微增率的计算模型。在考虑发电成本时,引进了煤炭价格因素,并建立了新的发电成本函数模型。最后以水电站总发电用水最少和火电站总发电成本最低为两个目标函数建立调度模型,并对该模型进行了优化计算。仿真计算结果表明了本文提出的调度准则具有可行性和适用性,能给系统调度员作出最佳决策提供一定的依据。     

Applying different decomposition schemes using the progressive hedging algorithm to the operation planning problem of a hydrothermal system

This paper addresses the solution of the Medium-Term Operation Planning (MTOP) problem. This operation scheduling problem aims to define the output of each power plant to minimize the expected production cost over a medium-term planning horizon. In hydrothermal systems, the MTOP is strongly influenced by the amount of water inflow to the reservoirs of hydroelectric plants, which is uncertain. Thus, the System Operator (SO) must consider these uncertainties in the problem resolution, which can be solved by means of Stochastic Programming (SP) techniques, such as the Progressive Hedging (PH) proposed in this paper. This paper presents suitable decomposition schemes to reduce the CPU time, such that it is possible to use a detailed model for the problem. Additionally, a parallel computational approach based on the PH algorithm is also implemented. To demonstrate the efficiency of the proposed schemes, a large hydrothermal system is investigated in the case studies.     

基于风险约束的风电和水电联合日前调度优化模型

为解决风电随机性对电力系统稳定运行的影响,引入梯级水电机组为风电机组提供调峰备用,构建了考虑风险约束的风电和水电联合日前调度优化模型。首先,分别构建了梯级水电机组输出功率模型、风电机组输出功率模型,以系统调度净收益期望值最大化作为目标函数,综合考虑风水电协调约束、系统功率平衡约束,构建了风水电联合调度模型。进一步,为了考虑风电不确定性给系统带来的风险因素,建立了计及风险约束的风水电联合随机优化调度模型,并采用启发式算法对模型进行线性化处理。最后,选择3个风力发电场和2个流域的7个水力发电厂组成仿真系统,对风水电联合调度优化进行算例仿真模拟。结果表明：所提出的水风电联合运行策略可以用来促进风力发电,最大化系统运营期望收益的同时最小化系统运营风险,因此,在进行风电和水电联合调度时应综合考虑内部和外部不确定性因素,以获得能够兼顾运营收益和风险的最优解。     

水电厂计算机监控系统改造的控制模式分析与设计

介绍了如何在保证满足电网调度集控中心的生产、设备控制要求同时完成水电厂计算机监控系统升级改造。     

A coordinated approach for real-time short term hydro scheduling

The paper describes a coordinated approach to short-term hydroelectric power generation scheduling and dispatch that has been developed as a part of the Tasmanian Hydro Electric Commission's new energy management system, which is being delivered by Landis and Gyr Energy Management. Tasmania's hydroelectric power generation system consists of 40 reservoirs in six river catchments. The daily water release for each plant is scheduled using the HEC's mid-term operation policy     

水火电力系统短期节能与经济发电优化调度

选取节能和经济两个决策目标,建立水火电力系统发电多目标优化调度模型,寻求满足决策目标的最优调度方案。根据水力发电和火力发电的能耗特性,引入同等装机容量技术条件下水煤转换系数的概念,建立了水火电力系统联合发电能耗模型以及火电综合成本模型,并选取水火电力系统发电等效总煤耗最小作为节能调度的目标,选取火电厂发电综合成本最小作为经济调度的目标,对含有梯级水电站群和多个火电厂的大区域性电力系统进行多目标优化调度。以一个具有8个梯级水电站和8个火电厂的水火电力系统为例进行仿真,其结果证明所建的节能与经济发电优化调度模型能够在增加发电量的同时,提高水资源利用率,节约煤炭资源,降低火电成本,创造良好的发电效益和经济效益。     

Daily Hydrothermal Generation Scheduling by a new Modified Adaptive Particle Swarm Optimization technique

The fundamental requirement of power system hydrothermal scheduling is to determine the optimal amount of generated powers for the hydro and thermal units of the system in the scheduling horizon of 1 day or few days while satisfying the constraints of the hydroelectric system, thermal plants and electrical power system. Daily Hydrothermal Generation Scheduling (DHGS) is a complicated non-linear, non-convex and non-smooth optimization problem with discontinuous solution space. To deal with this complicated problem, a new Modified Adaptive Particle Swarm Optimization (MAPSO) is proposed in this paper. The inertia weight and acceleration coefficients of the PSO are adaptively changed in the MAPSO owning tree topology. We split-up the cognitive behavior of PSO into the best and not-best parts. The proposed not-best cognitive component, unlike recent methods, retains its dynamic behavior throughout the search process. Personal best position exchanging method is proposed to increase activities of particles to explore broad space. New velocity limiter is also proposed in this paper to enhance exploration capability and convergence behavior of the MAPSO. The proposed MAPSO is tested on six test systems and compared with some recent research works in the area.     

Cost/environmentally compromised dispatch for cascaded hydrothermal system using artificial bee colony algorithm

This paper evaluates the robustness of the artificial bee colony (ABC) algorithm while allocating optimal power generation in a hydrothermal power system at the level of minimum fuel cost and minimum pollutant emission impacts on the environment subjected to physical and technical constraints. The hydrothermal scheduling (HTS) is devised in a bi‐objective framework so as to optimize both objectives of fuel cost and emission release, individually and simultaneously subjected to a verity of intricate equality and inequality constraints. Initially, all feasible solutions are obtained through random search, and then the ABC algorithm is used for the exploration and exploitation processes together in the search space, thereby discovering the optimal hourly schedule of power generation in the hydrothermal system. Meanwhile, a dependent hydro‐discharge computation handles the equality constraints; especially, the reservoir end volume and slack thermal generating unit for each sub‐interval handle the power balance equality constraint. The performance of the proposed approach is illustrated on a multi‐chain interconnected hydrothermal power system with due consideration of the water transport delay between connected reservoirs and transmission loss of system load. The results obtained from the proposed technique are compared with those of other techniques. The results demonstrate that the ABC algorithm is feasible and efficient for solving the HTS problem. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

梯级水电站多目标模糊优化调度模型及其求解方法

根据梯级水电站不仅具有电力联系而且具有水力联系的运行特点,提出一种以年发电量和一级水电站耗水量为优化目标的梯级水电站多目标长期优化调度模型.通过定义各目标的隶属度函数,将多目标优化问题模糊化;采用最大模糊满意度法将多目标优化问题转化为单目标非线性规划问题;应用协调粒子群算法(CPSO)求解单目标优化问题.仿真验证了模型的正确性和求解方法的可行性,为梯级水电站优化调度提供了一种新颖有效的途径.     

基于模糊机会约束规划的水火电力系统多目标随机调度模型

针对水火电力系统运行调度中所包含的不同种类的不确定量,提出了一种基于模糊随机机会约束规划的短期水火电力系统多目标优化调度模型。将调度周期开始的水库蓄水量作为一个三角模糊量,以描述初始蓄水预测可能存在的误差。针对某些随机变量可能由于历史数据不足而存在误差的问题,用模糊随机变量替代这些随机变量,描述水火电力系统运行中的不确定性。在考虑整个系统发电煤耗最小化和污染物排放最小化的目标同时,考虑了龙头电站周期末蓄水量最大的优化目标,并引入了火电机组煤耗量与梯级水电站蓄水量目标的协调函数。按照模糊机会约束和随机机会约束的确定性等价形式,将短期水火电调度不确定模型转化为确定性模型。以一个8级梯级水电站和6台火电机组组成的水火电力系统为实例进行计算,验证了所提出的水火电力系统随机调度模型的正确性。     

A contribution to the midterm scheduling of large scalehydrothermal power systems

A concise mathematical model and nonlinear minimization algorithm were presented as a joint approach to set optimal midterm production targets for power systems with predominance of hydroelectric power generation. The algorithm uses the network structure of the problem and takes into account nondifferentiable points. The approach was successfully applied to the optimal midterm scheduling of a very large hydroelectric power system in southeastern Brazil. Further insight into the problem allowed the adoption of an optimization-simulation strategy which achieved a very good suboptimal solution with great savings in computer requirements. The main purpose of this research was to develop a working tool able to assist engineers in setting optimized midterm targets for the large power systems in Brazil, where more than 90% of the electric energy comes from hydraulic sources     

包含多个小型水电站的随机生产模拟

随机生产模拟是电力市场中进行电价预测和发电调度管理的有力工具。传统的随机生产模拟方法对水火电机组间的电量调整较粗，当水电运行容量远小于邻近火电机组容量时，会造成较大误差；其次，传统的径流式水电站模型忽略了在较小的支流水系中来水的大幅随机波动，也将产生一定误差。在拥有大量小型水电站的地区性电力市场中，这些误差的积累会较严重地影响到市场信息公布及相关电力合约的签订。为此对传统的随机生产模拟进行改进，提出用电量迭代调整的方法准确处理小型有调节水库电站与大容量联络线等效机组运行位置交错的情况；建立考虑短时突发性洪水流量的径流式小水电随机生产模拟模型。对我国某地区电力系统的实际数据分析结果表明，该方法提高了随机生产模拟的准确性。