Youssef Ahmed Mobarak

This paper introduces the load flow on the Egypt Electricity Network system. The effect of capacitor compensation has been studied from three points. First, the problem of the series capacitor compensation was considered. The second type of compensation considered is shunt compensation. Finally, a mixed of shunt and series capacitors compensation was implemented. The analysis results were discussed based on the maximum reduction in the generated MVAR. The load variation is accounted for by considering three different load levels classified as light, medium and peak load with pre-specified durations. When solving the capacitor placement problem, the number, size, location and control settings of the capacitors at different load levels were determined. The load flow program is solved by the Power World Simulator (PWS) software. The results of series capacitor, shunt capacitor, and mixed compensation were studied. The investigation has been done for single capacitor and multi-capacitor compensation. Both 500kV and 220kV overhead lines have been considered.

Polymer properties can be experimentally tailored by adding small amounts of different nanoparticles for enhancing their mechanical, thermal and electrical properties. The work in this paper investigates enhancing the electric and dielectric properties of Low Density Polyethylene (LDPE), and High Density Polyethylene (HDPE) polymer materials with cheap nanoparticles. Certain percentages of clay and fumed silica nanoparticles are used to enhance electric and dielectric properties of polyethylene nanocomposites films. By using the Dielectric Spectroscopy; the electric and dielectric properties of each polyethylene nanocomposites have been measured with and without nanoparticles at various frequencies up to 1kHz under different thermal conditions (20°C and 60°C). And so, we were successful in specifying the optimal nanoparticles types and their concentrations for the control of electric and dielectric characterization.

A person’s understanding of a safety hazard has a dramatic effect on his or her behavior. An in-depth understanding of a hazard usually results in a healthy respect for what can happen. People who know the most about a specific hazard tend to rely more heavily on procedures and plans to guide their actions. Personal protective equipment selection and use are influenced by increased understanding of a hazard. Training and training programs are influenced by the depth of knowledge held by all members of the line organization. Recent work has focused attention on the thermal effects of arc flashes. However, when electrical energy is converted into thermal energy in an arcing fault, still another energy conversion is taking place. Applications are on record that suggest that a considerable amount of force is created during an arcing fault. Concrete block walls can be destroyed by the increased pressure that is created during an arcing fault. This study is present about preventing injuries to people. We will study about injuries and then develop some understanding about electrical hazards. Also, we will present about safe work practices, responsible, and then about what makes us act as we do.

Recently, Modular Multilevel Converter (MMC) has become one of the most popular converters in medium / high power applications. In this paper, a new technique is presented to decrease the computational time of the MMC by using switching state grouping for the predictive controller. The proposed technique has the ability to control the output current, minimize the circulating currents, and balance all capacitor voltages, simultaneously. For a predefined number of MMC submodules (SMs), the number of the available switching states is known. The proposed technique uses two stages of predictive modules. In the first stage, the switching states of the MMC are divided equally into a number of groups, controlled simultaneously by same number of predictive modules. The optimal number of the switching state groups in the first stage is obtained. In the second stage, only one predictive module is used to obtain the optimal switching state of the MMC without any other complexities or additional sorting controllers. The effectiveness of the proposed control technique has been verified by using MATLAB/SIMULINK software considering steady state and dynamic analysis. The results of the proposed technique are compared with the conventional one in terms of computation time, verifying a better performance of the proposed method.

Thermal Experimental Analysis for Dielectric Characterization of High Density Polyethylene Nanocomposites

The occurrence of voltage instabilities or voltage collapses depend on the duration of the persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities is the main goal of this paper. This paper searches for the effect of nodes short circuit levels NSCL and its duration periods initiation of voltage instability, with lagging and leading load power factors at certain loads buses. In this paper, the power system dynamic simulation program is developed for dynamic analysis of voltage stability. This paper is concerned with the fault duration which lead to the occurrence of voltage instability phenomena due to NSCL. The fault which lead to voltage instability is found to be short circuits at certain nodes cleared without any variation in the transmission system elements, i.e. the post-fault conditions will be the same as the pre-fault conditions. Models for loads considered in this study are induction motors with three different shaft mechanical loads, constant impedance CZ loads, constant current CI loads and constant power CP loads are used, as they depict the behavior of most power system loads. The influence of the transmission network impedances, which are nearly the inverse of the NSCL, on the fault duration which lead to the occurrence of voltage instabilities are studied and evaluated using various load representations.

The occurrence of voltage instabilities or voltage collapses depend on the duration of the persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities is the main goal of this paper. This paper searches for the effect of nodes short circuit levels NSCL and its duration periods initiation of voltage instability, with lagging and leading load power factors at certain loads buses. In this paper, the power system dynamic simulation program is developed for dynamic analysis of voltage stability. This paper is concerned with the fault duration which lead to the occurrence of voltage instability phenomena due to NSCL. The fault which lead to voltage instability is found to be short circuits at certain nodes cleared without any variation in the transmission system elements, i.e. the post-fault conditions will be the same as the pre-fault conditions. Models for loads considered in this study are induction motors with three different shaft mechanical loads, constant impedance CZ loads, constant current CI loads and constant power CP loads are used, as they depict the behavior of most power system loads. The influence of the transmission network impedances, which are nearly the inverse of the NSCL, on the fault duration which lead to the occurrence of voltage instabilities are studied and evaluated using various load representations.