Research paper
Behnam Alizadeh; Shahram Jadid
Volume 2, Issue 1 , June 2007, Pages 1-9
Abstract
This paper presents an application of Benders decomposition to deal with the complexities in the simultaneous Generation Expansion Planning (GEP) and Transmission Expansion Planning (TEP). Unlike the power system operation fields of study, the power system planning methods are not expected to be fast. ...
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This paper presents an application of Benders decomposition to deal with the complexities in the simultaneous Generation Expansion Planning (GEP) and Transmission Expansion Planning (TEP). Unlike the power system operation fields of study, the power system planning methods are not expected to be fast. However, it is always preferable to speed up computations to provide more analysis options for the planner. In this study, Benders decomposition has been applied to solve a mixed integer linear programming formulation of simultaneous GEP & TEP problem. The method has been tested on two test systems: Garver 6-bus system and IEEE 30-bus system. The results are compared to the unified solution of the problem formulation to show the consequent improvements from Benders decomposition.
Research paper
R. Baghipour; S.M. Hosseini
Volume 2, Issue 1 , June 2007, Pages 10-21
Abstract
In practical situations, distribution network loads are the mixtures of residential, industrial, and commercial types. This paper presents a hybrid optimization algorithm for the optimal placement of shunt capacitor banks in radial distribution networks in the presence of different voltage-dependent ...
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In practical situations, distribution network loads are the mixtures of residential, industrial, and commercial types. This paper presents a hybrid optimization algorithm for the optimal placement of shunt capacitor banks in radial distribution networks in the presence of different voltage-dependent load models. The algorithm is based on the combination of Genetic Algorithm (GA) and Binary Particle Swarm Optimization (BPSO) algorithm. For this purpose, an objective function including the cost of energy loss, reliability, and investment cost of the capacitor banks is considered. Also, the impacts of voltage-dependent load models, considering annual load duration curve, is taken into account. In addition, different types of customers such as industrial, residential, and commercial loads are considered for load modeling. Simulation results for 33-bus and 69-bus IEEE radial distribution networks using the proposed method are presented and compared with the other methods. The results showed that this method provided an economical solution for considerable loss reduction and reliability and voltage improvement.
Research paper
Behnam Mohammadi-Ivatloo; A. Mokari; H. Seyedi; S. Ghasemzadeh
Volume 2, Issue 1 , June 2007, Pages 22-31
Abstract
When a distribution network consisting of Distributed Generations (DGs) is disconnected from upstream network, the system may be exposed to severe power imbalance. In order to prevent the damage of power plants, frequency relays operate and remove DGs from the network. In contrast to traditional methods, ...
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When a distribution network consisting of Distributed Generations (DGs) is disconnected from upstream network, the system may be exposed to severe power imbalance. In order to prevent the damage of power plants, frequency relays operate and remove DGs from the network. In contrast to traditional methods, the main objective in new methods is to keep DG units in service in the islanded distribution system. Under-Frequency Load Shedding (UFLS) is one of the most important protection systems, which is the last chance for avoiding a system blackout following severe disturbance. This paper dealt with an adaptive UFLS method and considered the priority of loads to be shed, depending on the intensity of event, and loads look up table built by Rate of Change of Frequency of Loads (ROCOFL) indices based on the frequency of centre of inertia (fCOI). Different loads were shed depending on the event type diagnosed by measuring the initial Rate of Change of Frequency (ROCOF) in the method. The proposed UFLS method can stabilize the frequency of the distribution system in islanding mode by shedding sufficient loads. The simulation results confirmed the advantages of the methods in comparison to other proposed algorithms.
Research paper
K. Mazlumi; M. Mohammad Gholiha1; R. Abbasi; F. Mazlumi
Volume 2, Issue 1 , June 2007, Pages 32-39
Abstract
In this paper, a new method based on branch placement for the optimal positioning of Phasor Measurement Units (PMUs) in power systems is proposed. In this method, the PMUs are in type of single-channel and are installed at the beginning of the branches. Therefore, they are able to measure the bus voltages. ...
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In this paper, a new method based on branch placement for the optimal positioning of Phasor Measurement Units (PMUs) in power systems is proposed. In this method, the PMUs are in type of single-channel and are installed at the beginning of the branches. Therefore, they are able to measure the bus voltages. Also, the installation of the PMUs on the branches increases the security of observability in comparison to the bus placement method at the time of line or PMU outages. In this paper, the Genetic Algorithm (GA) method is used to solve the optimization problem. The proposed method is applied to IEEE 30-bus and 24-bus case study networks. In addition, the method is tested on a real 400 kV network in Iran.
Research paper
T. Barforoushi; M. Rasoulpoor
Volume 2, Issue 1 , June 2007, Pages 40-48
Abstract
Generally, the failure rate and the repair time of system components are constant parameters in reliability assessment of electric distribution systems. A failure of component is resulted from failing in the operation or overloading. In addition, there exist cases where, the repair times of components ...
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Generally, the failure rate and the repair time of system components are constant parameters in reliability assessment of electric distribution systems. A failure of component is resulted from failing in the operation or overloading. In addition, there exist cases where, the repair times of components are small and tolerable from customer point of view. Thus, tolerable repair times may be overlooked in the reliability evaluation of distribution systems. Therefore, by omitting the tolerable failures, reliability indices that are more reasonable, will be gained. In this paper, impacts of omitting customer tolerable repair time on electric distribution system reliability are studied. A simple model of circuit breaker, which differs from other components, is included. Monte Carlo simulation method is used for calculating reliability indices. A meshed distribution system is selected as a test system and simulations are performed and analyzed. Simulation results show that unavailability of load points are decreased resulting from omitting sustainable repair time, and also, it is required to include breaker model in distribution reliability evaluation.
Research paper
H. Khorramdel; B. Khorramdel; M. Tayebi Khorrami; H. Rastegar
Volume 2, Issue 1 , June 2007, Pages 49-59
Abstract
The major problem of wind turbines is the great variability of wind power production. The dynamic change of the wind speed returns the quantity of the power injected to networks. Therefore, wind–thermal generation scheduling problem plays a key role to implement clean power producers in a competitive ...
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The major problem of wind turbines is the great variability of wind power production. The dynamic change of the wind speed returns the quantity of the power injected to networks. Therefore, wind–thermal generation scheduling problem plays a key role to implement clean power producers in a competitive environment. In deregulated power systems, the scheduling problem has various objectives than in a traditional system which should be considered in economic scheduling. In this paper, a Multi-Objective Economic Load Dispatch (MOELD) model is developed for the system consisting of both thermal generators and wind turbines. Using two optimization methods, Sequential Quadratic Programming (SQP) and Particle Swarm Optimization (PSO), the system is optimally scheduled. The objective functions are total emission and total profit of units. The probability of stochastic wind power is included in the model as a constraint. This strategy, referred to as the Here-and-Now (HN) approach, avoids the probabilistic infeasibility appearing in conventional models. Based on the utilized model, the effect of stochastic wind speed on the objective functions can be readily assessed. Also a Total Index (TI) is presented to evaluate the simulation results. Also, the results show preference of PSO method to combine with HN approach.
Research paper
M. Darabian; A. Jalilvand; R. Noroozian
Volume 2, Issue 1 , June 2007, Pages 60-73
Abstract
In the past few decades, increasing growth of wind power plants causes different problems for the power quality in the grid. Normal and transient impacts of these units on the power grid clearly indicate the need to improve the quality of the electricity generated by them in the design of such systems. ...
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In the past few decades, increasing growth of wind power plants causes different problems for the power quality in the grid. Normal and transient impacts of these units on the power grid clearly indicate the need to improve the quality of the electricity generated by them in the design of such systems. Improving the efficiency of the large-scale wind system is dependent on the control parameters. The main contribution of this study is to propose a sensitivity analysis approach integrated with a novel hybrid approach combining wavelet transform, particle swarm optimization and an Adaptive-Network-based Fuzzy Inference System (ANFIS) known as Wavelet-ANFIS-PSO to acquire the optimal control of Doubly-Fed Induction Generators (DFIG) based wind generation. In order to mitigate the optimization complexity, sensitivity analysis is offered to identify the Unified Dominate Control Parameters (UDCP) rather than optimization of all parameters. The robustness of the proposed approach in finding optimal parameters, and consequently achieve a high dynamic performance is confirmed on two area power system under different operating conditions.
