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Generation scheduling is a crucial challenge in power systems especially under new environment of liberalization of electricity industry. This paper is focused on the economical aspect of UC problem, while the next load demand as a very important issue and prohibited operation zones and spinning reserve uncertainty as practical constraints have been taken in to account. The impacts of hot/cold start-up cost have been considered in this paper. Numerical results show a significant improvement in the solutions of a cost-based unit commitment in comparison with the other studies. © 2009 Praise Worthy Prize S.r.l  

The aim of this study is to show the effectiveness of prohibited operating zone. Generation scheduling is a crucial challenge in power systems especially under new environment of liberalization of electricity industry. This study is focused on the economical aspect of unit commitment problem. Since, the generating units may have certain ranges where operation is restricted based upon physical limitations of machine components or instability. Therefore, Prohibited Operating Zones (POZ) as a redundant constraint is considered, while the next load demand as a very important issue is deliberated. In this study generation scheduling of each hour is conducted by considering the next load demands... 

In this paper, a novel fast straightforward method for thermal generating units scheduling is presented. The new method decomposes the solution of the unit commitment (UC) problem into three subproblems. In the first subproblem, the quadratic cost functions of units are linearized and hourly optimum solution of UC is obtained considering all constraints except the minimum up/down time constraints. In the second subproblem, the minimum up/down times are enforced through a novel optimization process by modifying the schedule obtained in the first step. Finally, in the third subproblem, the extra reserve is minimized using a new decommitment algorithm. For testing the proposed method, the... 

On pool market structure, the generating units are typically dispatched in order of lowest to highest bid as needed to meet demand requirement as well as considering network constraints. Generally, no account is taken of generating unit's reliability when scheduling them. This paper proposes a new structure for electricity market to consider generating unit's reliability in the scheduling problem. GAMS (General Algebraic Modeling System) language has been used to solve the social welfare maximization problem using CPLEX optimization software with mixed integer programming. ©2006 IEEE  

In this study, the issue of allocating the cost of transient stability relief in a bilateral electricity market is investigated. The results of a constrained generation scheduling problem can be utilised in two ways to price the cost of a constraint. In the first method, which is the basis of nodal pricing, the Lagrange multipliers of the nodal power balance constraint are used as the price of electricity at various buses. In the second method, which is used in this study, the constraint relief scheme is based on a bid-based adjustment market of increments and decrements offered by generators to be involved in the constraint relief process. In the scheme used in this study, the cost of... 

In this paper, a self-generation scheduling method for a power generation company (GenCo) with renewable generation units is presented. In the proposed method, locational market prices (LMPs) are calculated using the incomplete information on competing market participants by simulating the ISO's market clearing program and considering the effect of physical limitations of transmission lines. The errors associated with forecasted LMP and renewable production are modeled in the GenCo's generation scheduling using a robust optimization approach. The scheduling problem is modeled as a mixed-integer linear programming which is solved by a CPLEX solver in GAMS. An eight-bus system is employed to... 

Wind power is a promising source of electric power generation since it has tremendous environmental and social benefits. The generation scheduling (GS) problem encounters several uncertainties in terms of the system's parameters such as load, reserve and available wind power generation. The modeling of those uncertainties is an important issue in power system scheduling. A fuzzy based modeling approach can be used to develop the generation schedule under an uncertain environment. In this paper, the type-2 fuzzy membership function (MF) is implemented to model the linguistic uncertainty of type-1 MF of available wind power generation which stems from opinions of different experts. The... 

Growing demand for flexible ramp products (FRPs) to maintain the power balance in active distribution networks (ADNs) has expanded the use of costly fast-start generators in the upstream real-time market. In order to limit the power system's reliance on these units, it is necessary to establish new sources for providing ADNs with FRPs. In this context, the present paper examines the abilities of distributed energy resources (DERs) and active loads for supplying the ramp capacity demands of ADNs. Accordingly, a local real-time market was established in the ADN, empowering several DERs and active loads to provide the network's FRPs demands. The proposed market was formed in the context of a... 

In this paper with studying of all parameters in grid environment a new scheduling algorithm for independent task is introduced according to Genetic Algorithm. This algorithm can be more efficient and more dependable than similar previous algorithms. The simulated results and reasons for reaching to better makes pan and more efficiency in the grid environment. In the grids with high fault with high fault rate for fault tolerant is used from check point method that has more efficiency that other methods such as retry, migration and replication. This method maintains effective efficiency in these situations. So the servicing quality increases in various grid environments and also the average... 

Wind power is a promising alternative in power generation because of its tremendous environmental and social benefits. Generation scheduling (GS) is more important in a power system integrating wind farms. Unlike conventional power generation sources, wind power generators supply intermittent power because of uncertainty in resource. This paper presents a fuzzy approach to the generation scheduling problem of a GenCo considering uncertainties in parameters or constraints such as load, reserve and available wind power generation. The modeling of constraints is an important issue in power system scheduling. A fuzzy optimization approach is an approach that can be used to obtain the generation... 

Integration of wind power generation creates new concerns for operation engineers in a power system. Unlike conventional power generation sources, wind power generators supply intermittent power due to uncertainty in parameters of wind such as its velocity. This paper presents probabilistic model for load and wind power uncertainty which can be used in operation planning (with durations up to one or two years). A stochastic model is proposed to simulate the status of units that are directly affected by the load and wind power generation uncertainties. This paper develops a solution method for generation scheduling of power system, while taking into account the stochastic behavior of the load... 

Purpose: The purpose of this paper is to investigate the impacts of electric vehicles' (EVs) charging/discharging decisions in energy resources scheduling problem of active distribution networks. Design/methodology/approach: The problem under study is modelled as a two-stage optimisation problem in which the main requirements of EV owners are introduced as an objective function of the first stage. The total energy costs and the emission factor are considered as the main criteria of the second stage. The output generation schedules of distributed generation (DG) technologies together with the charging/discharging schedule of EVs are proposed as decision variables of the energy scheduling... 

Large-scale integration of wind power in the electricity system presents some planning and operational difficulties, which are mainly due to the intermittent and difficult nature of wind prediction process. Therefore it is considered as an unreliable energy source. This paper presents a new approach for solving the generation scheduling (GS) problem. It will consider the reserve requirement, load balance and wind power availability constraints. The particle swarm optimization (PSO) method is suggested to deal with the equality and inequality constraints in the GS problem. The proposed PSO is applied to a 12-unit test system (including 10 conventional thermal generating units and 2 wind... 

Photovoltaic energy is one of the clean and efficient energies which has been developing quickly in the last years. As the penetration of solar plants is increasing in the electricity network, new problems have arisen in network operation. This paper models a high penetration factor of solar energy in the electricity network and investigates the impact of solar energy growth on both the generation schedule of different power plants and in the natural gas transmission network. Fuel management of gas power plants is modeled through simulation of the natural gas transmission network. To this end, an increase in the penetration of solar energy in the electricity network inevitably leads to a... 

Purpose: The purpose of this paper is to investigate the impacts of electric vehicles' (EVs) charging/discharging decisions in energy resources scheduling problem of active distribution networks. Design/methodology/approach: The problem under study is modelled as a two-stage optimisation problem in which the main requirements of EV owners are introduced as an objective function of the first stage. The total energy costs and the emission factor are considered as the main criteria of the second stage. The output generation schedules of distributed generation (DG) technologies together with the charging/discharging schedule of EVs are proposed as decision variables of the energy scheduling... 

This study presents a novel framework to incorporate the uncertainties associated with load fluctuations and components' availability in a day-ahead joint energy-reserve payment cost minimisation (PCM). The payments are calculated based on locational marginal prices (LMPs). Considering these uncertainties, appropriate definitions are not available for energy and reserve LMPs (RLMPs) that suit the probabilistic PCM formulation and reflect the market characteristics. A tri-level optimisation framework is proposed. The optimisation variables in the first-level optimisation include commitment status. In the second-level optimisation, the production schedule and allocated reserves are the... 

In order to generate adequate electricity energy, conventional power plants utilize dramatic volume of water resources. Different methods such as replacing cutting-edge technologies of facilities have been proposed to diminish water consumption in this industry. Most of the approaches are considered as medium or long-term solution which requires substantial investment costs. Meanwhile, because of the process and technology, natural gas-fired power plants need less water among conventional power plants. Therefore, shifting unit commitment planning toward these power plants would aid to save water consumption. Nevertheless, overlooking combined cycle power plants can perform negative impact on... 

Growing demand for flexible ramp products (FRPs) to maintain the power balance in active distribution networks (ADNs) has expanded the use of costly fast-start generators in the upstream real-time market. In order to limit the power system's reliance on these units, it is necessary to establish new sources for providing ADNs with FRPs. In this context, the present paper examines the abilities of distributed energy resources (DERs) and active loads for supplying the ramp capacity demands of ADNs. Accordingly, a local real-time market was established in the ADN, empowering several DERs and active loads to provide the network's FRPs demands. The proposed market was formed in the context of a... 

Wind power introduces a new challenge to system operators. Unlike conventional power generation sources, wind power generators supply intermittent power because of uncertainty in its resource. In a power system involved largescale wind power generation scenario, wind intermittency could oblige the system operator to allocate a greater reserve power, in order to compensate the possible mismatch between predicted and the actual wind power output. This would increase the total operation cost. This paper presents a new approach in fuzzy based generation scheduling (GS) problem using mixed integer nonlinear programming (MINLP). While the reserve requirements, load generation balance and wind...