الفهرس 
Smart Grid
Model and Cost Function for Distributed GeneratorsOnly 14 pages are availabe for public view
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Abstract
In traditional power system network, power flows through three stages: generation, transmission, and distribution. The power flows in one direction from generation until reaching final user in distribution network. In this configuration, the generation process has total authority of the electrical power system; this configuration is defined as a centralized electrical power system. Many problems appear in this configuration such as increasing loss in transmission power lines due to flow of power for large distance. Therefore, the smart grid was developed to improve the power system efficiency and reliability and overcome the issue of power losses in transmission lines. This is achieved through using advanced techniques in metering devices, bidirectional information, networking, and advanced control technology.
Distributed generators (DGs) are considered a main feature of a smart grid. DGs are defined as small units connected directly to a distribution network and can be based on Renewable Energy Sources (RES), such as wind and solar, or on traditional energy sources, such as diesel generators. On the other hand, many microgrids are developed through connecting many DGs together to supply a defined load in a rural region with the required power which is difficult to connect with the distribution network. These microgrids depend on RES; therefore, generation power from these sources is random as it depends on atmospheric condition, as well, the load is random depending on the load condition. Therefore an energy management system is necessary to be developed to balance between the active and reactive generation with the required active and reactive power under the operation conditions to achieve the optimal management.
Reactive power is very important in an electrical power system; it supports the transfer of the active power, supplies loads with the required reactive power and security operation of electrical power system since it can affect the voltage level. As reactive power is produced from generation units, the cost is no longer free and must be estimated. Therefore, an operation cost function for each generation unit must depend on active and reactive power cost. This study introduces an optimization operation cost for distributed generators (DGs) in microgrid depending on active and reactive power cost instead of active power cost only. This study achieves reaching optimal management and verifying the required active and reactive power with minimum cost to save stability of the system. The main contribution in this thesis is illustrated with the new technique which is presented as the Teaching-Learning-Based Optimization (TLBO) technique. The TLBO is used for solving the economic dispatch problem to obtain optimal management with the minimum cost.
In this thesis, it is considered that considering DGs operate as PQ type which have a known power factor for each DG. The model used is a smart microgrid containing three DGs (Diesel, Solar, and Wind) and, a capacitor bank to supply the load with the required active and reactive power. The model is applied on IEEE 33 Standard Test System. This study is divided to two parts; the first part objective is to clarify the efficiency of two optimization techniques in optimizing operation cost for the system depending on active and reactive power cost instead of active power cost only. The second part objective is to select the optimal sizing and siting of the capacitor bank to achieve minimum operation cost and improve the voltage level at all buses.