Intelligent stability margin improvement using series and shunt controllers

Electric market always prefers to use full capacity of existing power system to control the costs. Flexible alternate current transmission system (FACTS) devices introduced by Electric Power Research Institute (EPRI) to increase the usable capacity of power system. Placement of FACTS controllers in power system is a critical issue to reach their maximum advantages. This article focused on the application of FACTS devices to increase the stability of power system using artificial intelligence. Five types of series and shunt FACTS controllers are considered in this study. Continuation power flow (CPF) analysis used to calculate the collapse point of power systems. Controlling parameters of FACTS devices including their locations are determined using real number representation based genetic algorithm (RNRGA) in order to improve the secure margin of operating condition of power system. The 14 and 118 buses IEEE standard test systems are utilized to verify the recommended method. The achieved results manifestly proved the effectiveness of proposed intelligent method to increase the stability of power system by determining the optimum location and size of each type of FACTS devices.

The effectiveness of sunflower cultivation in the Southern chernozems of the Volgograd region by complex pre-sowing seed treatment

Sunflower is the main oilseed crop in Russia, at the same time it is widely used in the feed production. The purpose of the research was to improve the technology of sunflower cultivation in the zone of Southern chernozems in the Volgograd region by conducting a comprehensive presowing seed treatment in an electric field with subsequent seed treatment with a growth regulator in order to increase the yield and quality of oilseeds studied sunflower hybrids. According to the chosen experimental plan, three types of experiments have been carried out. During the first experiment, seeds of sunflower hybrids NK Neoma, LG 5550, EC Petunia have been treated in the alternate current electric field, in the second experiment the seeds have been treated with a growth regulator (the drug “Zerebra Agro”), in the third experiment the seeds have been subjected to a complex effect of electrophysical and biological factors. The level of profitability on sunflower hybrids NK Neoma, LG 5550 and EC Petunia in the control (without treatment) varied in the range of 147–200 %. Processing of sunflower seeds with the drug “Zerebra Agro” contributed to the increase in the level of profitability. On the sunflower hybrid of NK Neoma the profitability level was 178 %, on the sunflower hybrid LG 5550 it was 232 % and on the sunflower hybrid EC Petunia it was 171 %. When processing seeds in the alternate current electric field, the level of profitability was higher than when processing with the drug “Zerebra Agro”. On the sunflower hybrid of NK Neoma, the profitability level was 190 %, on the sunflower hybrid LG 5550 it was 252 % and on the sunflower hybrid EC Petunia it was 184 %. When using complex pre-sowing treatment, the maximum profitability value was achieved for sunflower hybrids NK Neoma, LG 5550 and EC Petunia 230 %, 271 and 201 %, respectively.

Effect of Yttrium Addition on Structure and Magnetic Properties of Co60Fe20Y20 Thin Films

In this paper, a Co60Fe20Y20 film was sputtered onto Si (100) substrates with thicknesses ranging from 10 to 50 nm under four conditions to investigate the structure, magnetic properties, and surface energy. Under four conditions, the crystal structure of the CoFeY films was found to be amorphous by an X-ray diffraction analyzer (XRD), suggesting that yttrium (Y) added into CoFe films and can be refined in grain size and insufficient annealing temperatures do not induce enough thermal driving force to support grain growth. The saturation magnetization (MS) and low-frequency alternate-current magnetic susceptibility (χac) increased with the increase of the thicknesses and annealing temperatures, indicating the thickness effect and Y can be refined grain size and improved ferromagnetic spin exchange coupling. The highest Ms and χac values of the Co60Fe20Y20 films were 883 emu/cm3 and 0.26 when the annealed temperature was 300 °C and the thickness was 50 nm. The optimal resonance frequency (fres) was 50 Hz with the maximum χac value, indicating it could be used at a low frequency range. Moreover, the surface energy increased with the increase of the thickness and annealing temperature. The maximum surface energy of the annealed 300 °C film was 30.02 mJ/mm2 at 50 nm. Based on the magnetic and surface energy results, the optimal thickness was 50 nm annealed at 300 °C, which has the highest Ms, χac, and a strong adhesion, which can be as a free or pinned layer that could be combined with the magnetic tunneling layer and applied in magnetic fields.

An Effective Approach Based on Deep Residual Google Net Convolutional Neural Network Classifier for the Detection of Glaucoma

Glaucoma is a disease caused by fluid pressure build-up in the inner eye. Early detection of glaucoma is critical as it is expected that 111.8 million people worldwide shall suffer from glaucoma in 2040. In the diagnosis of glaucoma, the use of machine learning method is hoped to be highly promising. This paper provides an important method to master learning to diagnose glaucoma. Initially, human retinal fundus images are preprocessed by means of histogram equalization in order to enhance them. The segmentation is performed by semantic segmentation method, mainly the features are extracted using density with correlation based feature extraction approach. PCA (principal component analysis) methodology is used to choose the most optimal features. Ultimately, through the usage of the Deep residual Google Net CNN Classification method, the retinal image is classified/predicted as regular and abnormal. The Deep residual Google Net CNN classifier is designed to distinguish view patterns with minimal pre-processing from pixel pictures. ORIGA and STARE datasets are used in this work. The findings are then analyzed and contrasted to illustrate the efficacy of the new technique with alternate current techniques. Test accuracy of 99%, Specificity of 98.9% and 100% Sensitivity were achieved. The quantitative results are analyzed for specifications like sensitivity, specificity, accuracy, positive predictive rate, false predictive rate and assured to provide excellent outcomes when compared with traditional methods.

STUDY OF THE PASSIVITY LIMITS OF AUSTENITIC STAINLESS-STEEL IN H2S-CONTAINING BRINES USING MOTT-SCHOTTKY AND POINT DEFECT MODEL ANALYSIS

The objective of the study is to correlate the effects of H<sub>2</sub>S, and Cl<sup>-</sup> concentration on the passivity limits and the onset of localized corrosion, in UNS S31603 stainless steel by evaluating the changes in the semiconducting behavior exhibited by the passive layer. The study is accomplished experimentally by using a combination of direct and alternate current electrochemical methods, to study the passive layer formed by the stainless steel, in equilibrium with a gas phase at 2.8 MPa (400 psi) containing up to 60% mol of H<sub>2</sub>S (bal. CO<sub>2</sub>) at 25○</sup>C. The results obtained using the Mott-Schottky analysis indicate that the decrease of the passive layer stability formed on the UNS S31603 stainless steel is consistent with the increase in the electron donor carrier density. This is observed as the consequence of the effect of Cl<sup>-</sup> and H<sub>2</sub>S. In this context, the Cl<sup>-</sup> content in the brine was found to exert a larger effect than the H<sub>2</sub>S activity. The correlation with the evaluation of the passive layer using the Point Defect model suggest that both the polarizability and the rate of annihilation of the cation vacancies at the metal / film interface increase with the H<sub>2</sub>S content in the environment. This behavior can explain the increased content of Cl<sup>-</sup> and sulfides as main electron donor species, also the observable increase in the passive layer susceptibility to both stable and metastable pitting.

Performance Analysis of a Hypothetical 1-Hectare PV Plant in the Benguela Region. The First Year of Operation.

The presents study evaluates the performance of a hypothetical 1-hectare solar photovoltaic (PV) plant located in the Baía Azul Beach, in Benguela, Angola. The first year performance of the plant composed by 2,784 DuoMax 365 PV modules from Trina Solar Company was evaluated by means of the VelaSolaris Polysum software package. The total surface area of the PV modules was of 5,456.64 m2. The annual alternate current electricity production was of 1,511.70 MWh allowing a total of 710.47 tCO2 of CO2 emissions reduction and a performance ratio of 72.8 %. The annual average energy and exergy efficiencies of the PV system were respectively of of 14.3 % and 14.7 %.

Performance analysis of a hypothetical 1-hectare PV plant in the Benguela region. The first year of operation.

The presents study evaluates the performance of a hypothetical 1-hectare solar photovoltaic (PV) plant located in the Baía Azul Beach, in Benguela, Angola. The first year performance of the plant composed by 2,784 DuoMax 365 PV modules from Trina Solar Company was evaluated by means of the VelaSolaris Polysum software package. The total surface area of the PV modules was of 5,456.64 m2. The annual alternate current electricity production was of 1,511.70 MWh allowing a total of 710.47 tCO2 of CO2 emissions reduction and a performance ratio of 72.8 %. The annual average energy and exergy efficiencies of the PV system were respectively of of 14.3 % and 14.7 %.

The design of an efficient class E-LCCL capacitive power transfer system through frequency tuning method

In this work, the optimum zero voltage switching (ZVS) of Class E-LCCL capacitive power transfer (CPT) was determined via frequency tuning method. Through this an efficient system can be guanranteed although there is a change in the capacitive plates distance. This study used a Class-E LCCL inverter, as it can operate at a high alternate current frequency, besides producing low switching losses and minimal power losses. Specifically, this study conducted simulations and experiments to analyse the performance of an LCCL CPT System at 1 MHz operating frequency and 24 V DC supply voltage. Using an air gap distance of 0.1 cm, the designed CPT system prototype successfully achieved an output power of 10W and an efficiency of 95.45%. This study also found that by tuning the resonant frequency of the Class E-LCCL system, the optimum ZVS can be obtained although capacitive plate distance was varied from 1-3 cm via experimental. The results of this study could benefit medical implant and portable device development, consumer electronics, and environments that involve electrical hazards.