Adel Z. El Dein

Experimental techniques to simulate naturally polluted high voltage transmission line insulators

This paper represents experimental techniques to simulate the naturally polluted high voltage insulators, under conditions that simulate the desert environment. Usually, the IEC fog method is used for testing the polluted insulators of high voltage transmission lines, but it does not simulate them under the desert pollution environments. For that reason, in this paper two other suggested techniques are added to the IEC one. The first one is to explain the performance of the polluted insulators under the dew and the second one is to explain their performance under the simultaneous fog and dew. The results of these three tests are compared with each other under different surface polluted layer conductivities. The aim of this paper is to record the leakage current and the warning voltage under different simulation weather conditions that to monitor the insulator strings before the occurrence of the flashover that of course is useful for the efficient maintenance. Also, in this paper, an attempt to simulate the flashover of the insulator in the field condition (actual outdoor condition) is presented. Where, the surface of the insulator is polluted naturally over a relatively long period, while it is permanently under high voltage.

Calculation of the Electric Field Around the Tower of the Overhead Transmission Lines

This paper presents the interaction between the overhead transmission lines (OHTLs) and their towers. In this paper, the electric field around the tower of the overhead transmission lines is calculated. The charge simulation method, combined with the image method, is used to develop a model that consists of subconductors of the OHTLs and the tower. The charges on the surface of each subconductor of the overhead transmission lines are simulated by a set of infinite line charges, of various charge densities, along the length of the subconductor, and the induced charges on the surface of the tower are simulated by a set of finite line charges.

Electrothermal Analysis of Low- and Medium-voltage Cable Joints

Abstract In this article, an analytical method to calculate the steady-state temperature distribution along the joint of a three-phase distribution cable is presented. The results of this method are compared with those obtained by an experimental study and by the finite-element method. It is found that the results of the analytical method are in good agreement with those obtained by an experimental study and by the finite-element method. The effects of connector dimensions as well as the effect of the ambient temperature and cable load current on the maximum temperature of the joint are discussed in detail. From the present analysis, it is found that the increasing of the connector length is more effective than the connector thickness in the reduction of the maximum temperature of conductor inside the joint.

Concentrated solar power plants impact on PV penetration level and grid flexibility under Egyptian climate

Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the output power of renewable energy. Simulation results show that the performance of CSP has a great impact on the penetration level of PV system and on the flexibility of the electric grid. The overall grid flexibility increases due to the ability of CSP to store and dispatch the generated power. In addition, CSP/TES itself has inherent flexibility. Therefore, CSP reduces the minimum generation constraint of the conventional generators that allows more penetration of the PV system.Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the outpu...

Electric power regulation and modeling of a central tower receiver power plant based on artificial neural network technique

This paper addresses an intelligent control scheme using the artificial neural network (ANN) technique for modeling and simulating a central tower receiver (CTR) plant with thermal energy storage (TES). The multilayer perceptron neural network (MLPNN) was implemented with two input parameters, one output parameter, and one hidden layer. The inputs comprise the receiver inlet temperature and the receiver thermal power. The output includes the mass flow rate of heat transfer fluid. A total of 888 datasets and three types of training algorithms, Levenberg-Marquardt (LM), Quasi-Newton, and Scaled Conjugate Gradient, are applied for training the proposed MLPNN model. Among all the investigated learning algorithms, the adopted LM with 40 neurons in the first hidden layer displayed superior ability to efficiently estimate the required performance compared to other learning algorithms. Based on the statistical evaluations, the optimized LM delivered preferred values for the root mean square error (0.0037), the coefficient of variance (0.0011), and the coefficient of determination (0.9999) during the training process. Hence, the MLPNN with LM-40 is an effective technique to precisely control the mass flow rate and subsequently the receiver outlet temperature regardless of the variations in the direct solar radiation and receiver inlet temperature. Furthermore, the generation strategy was modified to regulate CTR/TES output through electricity generation according to the hot storage system conditions. The performance of the adopted CTR-ANN model is presented and compared with the System Advisor Model (SAM) results. The results demonstrate better compatibility between the adopted CTR-ANN model and SAM outputs. The simplicity and minimum required input data of our proposed model make it appropriate for evaluating the power system reliability by using the Monte Carlo method.

Effect of functionalized TiO 2 nanoparticles on dielectric properties of PVC nanocomposites used in electrical insulating cables

The tendency to enhance the dielectric properties of insulating materials used in cables has become necessary in order to design new insulation systems that can withstand higher voltage levels. The current study is to investigate the improvement in dielectric properties of Polyvinyl Chloride (PVC) due to the insertion of chemically functionalized titanium oxide (TiO2) nanoparticles. The functionalization of TiO2 nanoparticles was performed using vinyl silane coupling agent. The PVC/TiO2 nanocomposites, with different weight fractions of nanoparticles up to 5 %, were fabricated using solution casting of PVC with the aid of nanoparticles dispersion within the molten polymeric matrix. The surface morphology of synthesized PVC/TiO2 nanocomposites was characterized by field emission scanning electron microscopy (FE-SEM). Then, their dielectric properties were studied by measuring and simulating the AC dielectric breakdown strength under quazi-uniform electric fields. The relative permittivity (εr) and dielectric loss (tan δ) were also measured in the frequency range 20 Hz to 1 MHz at room temperature. It is found that the dielectric breakdown strength of PVC was increased with incorporating functionalized TiO2 into their matrix compared to that with un-functionalized TiO2 or that of unfilled PVC. Furthermore, εr and tan δ were decreased by about 43% and 41%, respectively, over the unfilled PVC at 50 Hz. 3 % was found the optimal loading fraction of functionalized TiO2. This reveals that PVC/TiO2 nanocomposites with functionalized TiO2 had better dielectric properties. This may be attributed to the low surface energy of the functionalized TiO2 nanoparticles that prevented the agglomeration of nanoparticles and restricted the mobility of polymeric chains, and in turn, suppressed the free space charges resulting in a decrease in the capacitance and losses inside the nanocomposites.

Electro-thermal analysis of naturally cooled extra high voltage cable sealing end that provided with heat pipe as cooling method

In this paper, an analytical method for the thermal analysis of naturally cooled high voltage cable sealing end provided with heat pipe as method of cooling is introduced. In this analytical method, the axial heat flow as well as the heat convection and radiation are taken into account. To validate the analytical method, a comparison between the experimental results that done by others, the finite element method results and the results obtained by this analytical method is done. It is noticed that there is a good agreement between the results of the three methods. Finally, the analytical method is used to investigate the effect of ambient temperature and the thermal resistivity of the insulation on the temperature distribution along the sealing end and the adjacent cable parts.

Simulation of capacitor-switching with and without utilizing mitigation method

Capacitor switching is one of the most important sources of generating transient overvoltage and inrush current of electrical power system. Energizing transient may reduce the life span of capacitor banks, damage of power system equipment and insulation failure. This paper, presents three technologies used to mitigate transients caused by capacitor switching. ATP program is used to simulate capacitor switching with and without utilizing mitigating methods.

Prediction of Egyptian 500-kV Overhead Transmission Line’s Radio Interference by Using the Excitation Function

This article presents applications of the excitation function on the prediction of the radio interference (RI) of overhead transmission line (OHTL), due to corona effect. These applications are done under different weather conditions such as heavy rain, wet conductor, and fair weather. Also, this article investigates the factors influencing the RI level, namely, the height of conductors, phase spacing, number of subconductors in the bundle, diameter of subconductor, and subconductor spacing in the bundle. In this article, it is shown that the RI level is dependent on the weather conditions. Where the RI level under heavy rain has the maximum level, hence, it should be considered as a basic level of any OHTL.