Sharif Digital Repository

When there are transmission service requests for a specific sink/source pair in a transmission system, the ISO must allocate the ATC of that pair to the requests. Since the requests could have different types, tariffs and time frame, the allocation must be accomplished in a sound and fair manner that considers various aspects of the requests. This paper proposes an approach to allocate the ATC to transmission service requests in both operating and planning horizons. The proposed method considers types and tariffs of requests in a nonlinear optimization which maximizes the expected net revenue of ATC allocation. The solution to the optimization problem gives the amount of accepted requests.... 

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 paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches  

In this paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches  

The architecture of the Cascading TMR (Triple Modular Redundancy) System is commonly found in aerospace applications. The system is potentially capable of containing a large number of modules and sub modules. In this paper a novel method for optimization of a Cascading TMR system configuration using GA (Genetic Algorithm) is proposed. The proposed algorithm provides a configuration that maximizes reliability and minimizes overhead area simultaneously  

A mechanical system inherently affected by the conditions, factors, and parameters of uncertainties. Without including the uncertainty effects in the design procedure, the designs may not be robust and reliable. Robust design optimization (RDO) method is a procedure to find the insensitive design with respect to the variations. On the other hand, reliability is measured by the probability of satisfying a specific design criterion. Therefore, a reliable design is a design that satisfies the specified criteria even with some uncertainties in variables and parameters. Reliability-based design optimization (RBDO) is an optimization procedure that incorporates reliability requirements to find the... 

When there are transmission service requests for a specific sink/source pair in a transmission system, the ISO must allocate the available transfer capacity (ATC) of that pair to the requests. Since the requests could have different types, tariffs and time frames, the allocation must be accomplished in a sound and fair manner that incorporates various aspects of the requests. This paper proposes a comprehensive approach to allocation of ATC to transmission service requests. The proposed method considers types, tariffs, and priority of requests in a mixed-integer nonlinear optimization which incorporates the allocation rules. The solution to the optimization problem gives the amount of... 

Achieving high-distribution reliability levels and concurrently minimizing capital costs can be considered as the main issues in distribution system optimization. Determination of the optimum number and location of switches in distribution system automation is an important issue from the reliability and economical points of view. In this paper, a novel three-state approach inspired from the discrete version of a powerful heuristic algorithm, particle swarm optimization, is developed and presented to determine the optimum number and locations of two types of switches (sectionalizers and breakers) in radial distribution systems. The novelty of the proposed algorithm is to simultaneously... 

A redundancy allocation problem consists of the selection of a number of redundancies to be allocated in each subsystem of a series-parallel configuration to maximize system reliability, while minimizing overall system cost. Most existing studies either ignore system cost or assume deterministic component reliabilities. However, the selection of a network system design requires the estimation of its reliability and cost. Therefore, the uncertainty associated with such estimates must be considered in the decision process. In this study, an efficient method based on the loss function approach is proposed to solve the redundancy allocation problem. This approach not only optimizes the overall... 

Bi-objective optimization of a multi-product multi-period three-echelon supply chain network consisting of manufacturing plants, distribution centers (DCs) each with uncertain services, and customer nodes is aimed in this paper. The two objectives are minimization of the total cost while maximizing the average number of products dispatched to customers. The decision variables are: (1) the number and the locations of reliable DCs in the network, (2) the optimum number of items produced by plants, (3) the optimum quantity of transported products, (4) the optimum inventory of products at DCs and plants, and (5) the optimum shortage quantity of the customer nodes. The problem is first formulated... 

Nowadays automation in distribution systems is growing largely. Automated and remote controlled switches play prominent rules in automated distribution systems. By opening and closing these remote controlled switches in emergency states when a fault has been occurred we can manage fault and restoration process in order to minimize interruption time and costs. In the normal states feeder load management and power loss minimization can be controlled by these remote controlled switches. Finding optimum numbers and optimum locations for installing these switches is the main concern in this between. Up to now a number of algorithms have been developed for optimum switch placement. In this paper a... 

Considerable attention has been devoted to demonstrate reliability enhancement of power systems with power wheeling transactions. The impacts of power wheeling on power systems depends on various factors such as direction, amount of power/energy wheeled, system topology and sink or source nodes of power system. The effects on Iran Composite Power System (ICPS) reliability of wheeling energy from Azerbaijan to Turkmenistan are presented in this paper. This transaction is done through the transmission facilities on north part of ICPS. The sensitivity of ICPS to the direction and amount of power wheeling is attended. Finally, the optimum value for power wheeling is determined and the associated... 

Fast charging stations are vital components for public acceptance of electric vehicle (EV). The stations are connected to the electric grid and can recharge an electric vehicle in less than 20. min. Charging station development is highly influenced by the government policy in allocating station development costs. This paper presents a Mixed-Integer Non-Linear (MINLP) optimization approach for optimal placing and sizing of the fast charging stations. The station development cost, EV energy loss, electric gird loss as well as the location of electric substations and urban roads are among the factors included in the proposed approach. Geographic information has been used to determine EV energy... 

In the natural gas transmission network, from supply points to demand nods there are various technological options that include processing, transportation, conversion and gas distribution. Comprehensive analysis of natural gas network requires evaluation of different chains of gas flow through various levels based on economical and environmental criteria subject to technical and operational constraints such as feasibility, operability and reliability of different alternatives. To aid decision-making process in the sector of natural gas, a generic optimization-based model has been developed for assessing long term energy issues related to planning and design of natural gas supply systems. The... 

Here, an approach for finding an optimal path in a flexible jobshop manufacturing system considering two criteria of time and cost is proposed. A network is configured in which the nodes are considered to be the shops with arcs representing the paths among the shops. An automated guided vehicle functions as a material handling device through the manufacturing network. To account for uncertainty, time is considered to be a triangular fuzzy number and apply an expert system to infer the cost. The expert system based on fuzzy rule backpropagation network to configure the rules for estimating the cost under uncertainty is proposed. A multiple linear regression model is applied to analyze the... 

This paper focuses on multi-objective reliability optimization of a two-stage launch vehicle using a hybridized Genetic Algorithm-Particle Swarm Optimization with provisions of relative weighting between the objectives. In this respect, the launch vehicle key subsystems as well as their functions are initially introduced. Subsequently, the system reliability block diagram is constructed using the launch vehicle working order of the subsystems augmented with the requirements for a robust fault/failure tolerant design and performance. Next, based on the proposed reliability block diagram arrangement a bi-objective optimization is formulated to maximize the system reliability while minimizing... 

Minimization of operating costs is one of the most important objectives of power system operators. To achieve this goal, several optimization problems such as unit commitment and optimal power flow have been introduced. Historically, in these problems, the transmission network has been considered as a static system, i.e., the ability of transmission lines switching is not modeled. On the other hand, it has been shown that transmission line switching can significantly reduce operating costs by the means of topology modification. However, considering this capability, a large number of binary variables are introduced in the objective function, and as a consequence, the computation time will be... 

Distribution feeder reconfiguration (DFR) is a precious operation strategy that can improve the system from different aspects including total cost, reliability, and power quality. Nevertheless, the high complexity of the new smart grids has resulted in much uncertainty in the DFR problem that necessities the use of a sufficient stochastic framework to deal with them. In this way, this paper proposes a new stochastic framework based on cloud theory to account the uncertainties associated with multiobjective DFR problem from the reliability point of view. Cloud theory is constructed based on fuzzy theory and probability idea. In comparison with the Monte Carlo simulation method, cloud models...