ملخص البحث :

The distribution system represents the connection between the consumers and entire power network. The radial structure is preferred for distribution system due to its simple design and low cost. It suffers from problems of rising power losses higher than the transmission system and voltage drop. One of the important solutions to evolve the system voltage profile and to lower system losses is the reactive power compensation which is based on the optimum choice of position and capacitor size in the network. Different models of loads such as constant power (P), constant current (I), constant impedance (Z), and composite (ZIP) are implemented with comparisons among them in order to identify the most effective load type that produces the optimal settlement for minimization loss reduction, voltage profile enhancement and cost savings. Dolphin Optimization Algorithm (DOA) is applied for selecting the sizes and locations of capacitors. Two case studies (IEEE 16-bus and 33-bus) are employed to evaluate the different load models with optimal reactive power compensation. The results show that ZIP model is the best to produce the optimal solution for capacitors position and sizes. Comparison of results with literature works shows that DOA is the most robust among the other algorithms.

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Radial Distribution System (RDS) suffer from high real power losses and lower bus voltages. Distribution System Reconfiguration (DSR) and Optimal Capacitor Placement (OCP) techniques are ones of the most economic and efficient approaches for loss reduction and voltage profile improvement while satisfy RDS constraints. The advantages of these two approaches can be concentrated using of both techniques together. In this study two techniques are used in different ways. First, the DSR technique is applied individually. Second, the dual technique has been adopted of DSR followed by OCP in order to identify the technique that provides the most effective performance. Three optimization algorithms have been used to obtain the optimal design in individual and dual technique. Two IEEE case studies (33bus, and 69 bus) used to check the effectiveness of proposed approaches. A Direct Backward Forward Sweep Method (DBFSM) has been used in order to calculate the total losses and voltage of each bus. Results show the capability of the proposed dual technique using Modified Biogeography Based Optimization (MBBO) algorithm to find the optimal solution for significant loss reduction and voltage profile enhancement. In addition, comparisons with literature works done to show the superiority of proposed algorithms in both techniques.

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Distribution System Reconfiguration (DSR) and Optimal Capacitor Placement (OCP) are the most alternative techniques for increasing the power system generation and covering the growth of power demands. ,ese techniques reduce the Radial Distribution System (RDS) losses and enhance the voltage profile. Combining both techniques gives better performance than using the individual technique. In this paper, two operation modes were implemented. First, the individual mode of OCP is applied. Second, the dual mode of DSR after OCP process is applied. Multiobjective functions with considering the weighting factors are used for minimizing real losses, improving voltage profile, and increasing saving cost. ,e optimal selections of open switches, location, and size of capacitors in the individual and dual design for RDS are achieved using four different optimization algorithms. ,ese algorithms are Modified Biogeography-Based Optimization (MBBO) algorithm, Cuckoo Search (CS) algorithm, Modified Imperialist Competitive (MIC) algorithm, and Modified Bacterial Foraging-Based Optimization (MBFBO) algorithm. ,ese algorithms are applied for two standard networks (IEEE 33- and IEEE 69-bus). Comparisons among the proposed algorithms are done, and the results demonstrated that the MBBO algorithm is the most strong and fast algorithm to attain the optimum solution. In addition, comparisons with literature works are done to validate the effectiveness of proposed algorithms.

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Voltage stability represents one of the main issues in electrical power system. Under voltage load shedding (UVLS) has long been regarded as one of the most successful techniques to prevent the voltage collapse. However, the ordinary load shedding schemes do not consider the different load models and decreasing in the economic cost that resulted from load disconnection, so the dual techniques of load shedding with reactive compensation are needed. Usually loads being modeled as constant power, while in fact of load flow the various load models are utilized. An investigation of optimal dual load shedding with reactive compensation for distribution system based on direct backward forward sweep method (DBFSM) load flow along with a comparison among the other load models are presented in this paper. The teaching learning-based optimization (TLBO) algorithm is executed in order to reduce power losses and enhance the voltage profile. This algorithm is tested and applied to IEEE-16 bus distribution test system to find the optimal superior capacitor size and placement while minimizing load shading for the network. Five different load shedding sequences are considered and the optimization performance of load models demonstrated the comparison through MATLAB program.

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Study and analysis the effect of variable applied voltage on SCIM performances based on FEA is presented. Three phase squirrel cage induction motor SCIM has been investigated and numerically simulated using finite element method (FEM) with the aid of ANSYS software (RMxprt and Maxwell 2D/3D). This research presents study and analysis of the effects of the voltage variation on performance and efficiency of the three-phase induction motor of the squirrel cage type. The Finite Elements Analysis Method FEA is used as one of the best methods for analysis and simulation of electrical motors in addition to the possibility of dealing with nonlinear equations, Since the induction motor is a complex electromagnetic reaction, the researchers used the ANSYS program to represent and analyze the performance of the motor under variable supply voltage. The case studied in this research is three phases, 380V, 50Hz, 2.2kW, induction motor that widely use in industrial application. The aim of this research is to study the effect of voltage variation on efficiency, current value, power factor and torque of SCIM. The RMxprt software has been used for modeling and simulating the induction motor and calculating the values of phases currents, input and output power in additional of overall efficiency at steady state condition. The next stage of the research is creating Maxwell 2-D design from the base model of RMxprt software, Maxwell 2-D model has the ability to computing the distribution of magnetic field and explaining the performance under steady-state operation. The obtained results show significant reduction of motor performance due to the effect of variation of apply voltage.

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The electrical distribution system is the interface between the power system and customers. Because of its compact architecture and low expense, the radial configuration is favored for distribution systems. Reactive Power Compensation (RPC) that is dependent on the optimal option of location and capacitor size in the network is one of the essential settlements for reducing network losses and adjusting the device voltage profile. Various load models, including constants of impedance (Z), current (I), power (P), and composite (ZIP), are used with contrasts between them to define the highest productive kind of load, which provides the optimum settlement for loss minimization, improving cost and voltage profile reductions. In this paper, a study of optimal Reactive Compensation (RC) with a comparison and assessment between two load flow methods Newton Raphson and Backward-Forward load flow methods (DBFSM), considering miscellaneous models of the load, is present for a distribution power system. The optimization algorithm based on Teaching-Learning (TLBO) is applied to refine the voltage values of buses and losses reduction. This algorithm has been tested for the IEEE-33 standard distribution power system. Comprehensive comparison and assessment have been accomplished among the optimization performances for four diverse load models in order to decide the model of load that provides the most betterment in the voltage profile and loss detraction using MATLAB program.

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Abstract—Distribution System Reconfiguration (DSR) is a complex action that changes the topology of distribution system by altering the status of its switches to afford radial construction with lower losses and confirm operating limits. In this paper, a comparison is made between two power flow methods, Direct Backward Forward Sweep Method (DBFSM) and Newton Raphson Method (NRM) to perform optimal DSR. Qualified Binary Particle Swarm Optimization (QBPSO) algorithm is used to obtain optimal DSR. Two standard networks (IEEE-16 bus, and IEEE-33 bus) are used to explain comparisons between two load flow methods. The using of DBFSM led to a significant influences in the minimizing of power losses and achieve more improvement in the voltage profile for both 16 bus and 33 bus RDS. The tabulated results and figures show that the DBFSM is more fast and robust

ملخص البحث :

The distribution system connects customers to the rest of the electrical grid. The electrical distribution network suffers from rising power losses and low frequency, which are greater than transmission system and low voltage problems. One of the solutions for these problems furnished by under-frequency load shedding based on optimal selection of loads using a suitable optimization algorithm. Because of its simple design and inexpensive cost, the radial distribution system (RDS) was chosen. Two load models (constant power model and ZIP model) are implemented with comparisons between them. A Gravitational binary search optimization algorithm is used for the purpose of accurate results, and comparisons are made to demonstrate the efficiency of the proposed method. A BGSA optimization algorithm is useful in order to reduce the search space for the minimum power to be shed and its location. IEEE 33- bus is employed to check the validity of suggested attitudes. A Direct Backward Forward Sweep Method (DBFSM) is used to show the voltage and total losses of each node as it represents the useful load flow method suitable in RDS. The results demonstrate the ability of the provided methodologies to find the best solution for a large loss reduction and a better voltage profile using the BGSA optimization algorithm

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The growing demand for electricity and the distance between the power plants and the loads pose a threat to voltage stability and the equilibrium between supply and demand. The system also experiences significant losses in distribution networks and extreme strain on transmission lines. The reliance of the generation on fossil fuels, on the other hand, poses a future issue in terms of shortage as well as the rise in environmental contaminants. The idea of a microgrid is one of the creative ways to combine dispersed energy sources and the utility grid and manage them as a single system. Microgrid may boost system dependability, improve the distribution network, and lessen the strain on the transmission lines. Distributed generator (DG) is put directly in the load center distribution network or at the distribution network. The voltage profile of the system will be improved and overall power losses can be decreased with the help of optimal DG allocation. This paper presents a method for optimally siting and sizing distributed generation (DG) units in a microgrid by binary particle swarm optimization. The DOLPHIN optimization algorithm (DOA) utilizes under voltage load shedding (UVLS). The Direct Backward Forward Sweep Method depicts the practical load flow technique suited in radial distribution system (RDS), as it’s utilized to display the voltage profile and total losses of each node with and without DG and load shed. Four load models were used (normal, constant current, constant impedance, and ZIP model) with comparisons between them. The RDS of the typical bus is simulated using MATLAB programmin