The Transient Stability Study of a Synchronous Generator Based on the Rotor Angle Stability

Transient stability is an important aspect in the operation of electrical power system. In case of fault occurs in the system, the determining of fault clearing time of circuit breaker is considered one of the main factors to ensure power transfer of the system. This paper is aim to study the transient stability of single machine infinite bus system (SMIB), based on the rotor angle stability. The study is performed to determine the influence of the critical clearing time of the circuit breakers on the rotor angle stability of the generator in the case of three phase fault. For obtaining and determining numerically the nature of the rotor angle of machine, we applied the Step-by-step method for different values of fault clearing time. The results of simulation indicate that determine of critical clearing time is a major evaluation in stability studies. The system model is created in MATLAB/ SIMULINK software

A Neuro-fuzzy Approach for Predicting Load Peak Profile

Load forecasting has many applications for power systems, including energy purchasing and generation, load switching, contract evaluation, and infrastructure development. Load forecasting is a complex mathematical process characterized by random data and a multitude of input variables.To solve load forecasting, two different approaches are used, the traditional and the intelligent one.Intelligent systems have proved their efficiency in load forecasting domain. Adaptive neuro-fuzzy inference systems (ANFIS) are a combination of two intelligent techniques where we can get neural networks and fuzzy logics advantages simultaneously. In this paper, we will forecast night load peak of Algerian power system using multivariate input adaptive neuro-fuzzy inference system (ANFIS) introducing the effect of the temperature and type of the day as input variables

Optimal number and location of UPFC devices to enhence voltage profile and minimizing losses in electrical power systems

The fast increase of loads around the world has made electrical networks more and more complex and difficult to operate close to its capacities. This is has led to many problems such as voltage collapse and energy losses. Therefore, flexible alternating current transmission systems (FACTS) are considred as a best solution for solving these problems. Unified Power Flow Controller UPFC is one of the most important and powerful FACTS devices due to its ability to increase the transmission capacity of the power system and reduce the total line losses. The problem of optimizing its number, location and size has become an important requirement for best advantages of this device. In this paper, a proposed relationship to identify the maximum number of FACTS devices that can be installed for a given power network is introduced in the search process code to determine the optimal number, optimal placement and size of UPFC device to enhance voltages profile and reduce overall system losses in the standard IEEE 14 bus test system using genetic algorithm (GA). The obtained results show clearly that all control parameters of UPFCs in each case are within their limits, and whenever the number of UPFCs installed increases, both voltage deviation and total losses well decreases. They also show that the application of the proposed relationship in the search process code facilitates greatly the search for optimal number, optimal placement and size of UPFC devices and reduces the calculation time. On the other hand, the obtained results has been scientifically justified and compared with other works reported in the literature

Control of Power and Voltage of Solar Grid Connected

Renewable energy is high on international agendas. Currently, grid-connected photovoltaic systems are a popular technology to convert solar energy into electricity. Control of power injected into the grid, maximum power point, high efficiency, and low total harmonic distortion of the currents injected into the grid are the requirements for inverter connection into the grid. Consequently, the performance of the inverters connected to the grid depends largely on the control strategy applied. In this paper the simulation and design of grid connected three phase photovoltaic system using Matlab/Simulink has examined. The proposed system consists photovoltaic panels, boost and inverter the PV system convert the sun irradiation into direct current, thereafter we have used a boost to track the maximum power point of the PV system, three-phase inverter and LC output filter. A VOC control strategy based on the phase shifting of the inverter output voltage with respect to the grid voltage. The proposed control strategy requires few hardware and computational resources. As a result, the inverter implementation is simple, and it becomes an attractive solution for low power grid connected applications

Active and reactive power sharing in micro grid using droop control

The development of renewable energy contributes to the global objectives of reducing our greenhouse gas emissions, obtaining and increasing our energy efficiency. In the face of these changes, the electric-network must adapt, while maintaining a high level of reliability and a quality of energy production. To meet this objective, it is recommended to use highly developed electrical network by integrating renewable energy sources in order to adapt the energy consumption to their production, using electro-technical software information and telecommunications technologies. We are talking about intelligent grids (Smart Grid). The main objective of the work presented in this paper is the contribution to the study of intelligent network for efficient management of energy produced by several sources linked to the AC bus via the voltage inverters. Numerical simulations have been presented to validate the performance of the proposed active and reactive power controller (Droop Control)

Induced Lightning Disturbances in Overhead Shielded Cables Modeling by Current Generators

AbstractIn this work we study the coupling of a lightning wave with overhead shielded cables. This study allows us to deduce the currents and voltages induced across the ends of the cable directly. In our work, we propose to represent the electromagnetic excitation distributed along a cable located in a node (end or junction) generator. This approach will lead us to reduce the analysis of the coupling of an object illuminated by a lightning wave in a problem of an excited simultaneously by several generators disposed on all nodes of the cable. Currents and voltages induced on all nodes of the cable shall be deducted by simple resolution of a system of linear equations

Understanding the impact of desert stressors factors on standard PV panel performance: Case study of Algeria's desert

Compared to moderate climate conditions, hot and dry environment, as known desert, present the most difficult environment that affects negatively PV panels performance. In the present paper, the root causes that have the major contribution in PV panel performance degradation in desert climates and the direct relationship between desert climate factors and accelerate degradation mechanism are analyzed. Algeria's desert is chosen as a case to study, an overview of Algeria's desert climate has been presented. High solar irradiation accompanied by high ambient temperature has been considered as the most responsible for accelerated discoloration and initiating damage of EVA encapsulant material which can create a challenge for long-term reliability of c-Si PV panels. The declared 20–25 year PV panel lifetime is very optimistic in Algeria's desert climates. This research work can be beneficial in future studies on challenges related to the optimal performance and the expected operating lifetime of photovoltaic applications in desert climates