Papers by Keyword: Capacitor

Abstract: This paper solves the problem of optimal sizing and locations of capacitors in radial distribution system using a new hybrid method combining a new stability index and a genetic algorithm to improve the loss, voltage and stability planes. The Bus Voltage Stability Index BVSI is used to determine the locations and the genetic algorithm GA to calculate the size. The GA-BVSI analytical-metaheuristic method, compared with existing methods, is more suitable and recommended for operators who are faced with the problem of sizing capacitors to improve the technical performance of their network. Keywords: Optimal sizing and locations; Capacitors; Radial distribution system; New stability index; Hybrid method.

Abstract: In this article, the structural, microstructural, and dielectric properties of Lead- free perovskite ceramic Bi_0.5(Na_0.78K_0.22)_0.5TiO₃ [BNKT] have been reported. The material was synthesized through the solid-state reaction method. The compound formed is found to have a hexagonal structure, confirmed by XRD analysis of the sample. The microstructural analysis of the compound revealed the polycrystalline nature of the ceramic having quasi-cubic grain morphology with distinct grain boundaries. From the dielectric study, it was found that the dielectric constant increases with temperature and attained maximum value at temperature T_c = 335° C, after which it decreased. The frequency independence of transition temperature (T_c) suggested the classic ferroelectric behaviour of the compound. The broad dielectric peak around transition temperature confirms the relaxor behaviour of the compound as well as diffused phase transition at T_c. The value of the relative permittivity and loss tangent at ambient temperature for 1kHz frequency is 627 and 0.223 respectively. The synthesized material can be utilized for the fabrication of capacitors and energy storage applications.

Abstract: CuO nanorods were fabricated by a facile microwave-assisted synthesis method and applied to pseudo-capacitor. The CuO nanorods were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The capacitive behavior of nanorods was investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. Electrochemical experiments reveal that CuO nanorods demonstrate better capacitance performance than granular CuOs prepared by chemical precipitation method. The CuO nanorods have a high specific capacitance of 317 F/g at a current density of 1 A/g and a fairly good cyclic stability.

Abstract: This paper analyzed how capacitor has an effect on the hybrid ignition system; especially the accumulated energy. Matlab was used to simulate the primary current, self – induced emf, oscillation frequency and accumulated energy. The experiment data - primary current, self-induced emf, oscillation frequency and dwell time - was collected via PicoScope 4425 Automotive Oscilloscope. Simulation results show that the accumulated energy in capacitors is greater than the required ignition energy, which ensure hybrid system working fluently.

Abstract: As the pumped storage stations played an important role in peak and frequency modulation, the reversible pump turbines were often subjected to rapid temperature transitions. In this research, considering the complexity operation condition of these kinds of motors, a novel thermal cycle aging platform was designed and the thermal cycling aging test was conducted on epoxy/mica insulation stator bars. Dielectric loss angle tangent (tanδ), capacitor (C), leakage current (I) and other electrical properties of stator bars were investigated at different aging time. The results showed that, tanδ and C of the stator bars increased with increasing aging time, while I (current) did not change significantly.

Abstract: As one of the most important parts of the generator, Epoxy/mica insulation system has the direct effect on the reliability of generator operation. The accelerated aging of insulation system was taking place under the complex operation condition, and resulting in the insulation system breakdown. It had always been the target for the researchers to find an efficient way to evaluate the state of generator insulation system. According to the real operation situation, the multi-factor aging test sequence with electric field, temperature field, mechanical vibration and thermal cycling was developed, and the test platform with multi-factor aging was built in this research. The partial discharge test was conducted at the end of each cycle. The result showed that, with the insulation aging time prolonged, the maximum partial discharge quantity decreased first then increased while skewness and kurtosis varied the opposite way. And the phase range of partial discharge began to expand. This research provided a new way to evaluate the state of generator insulation system.

Abstract: Method of determining parameters of electrochemical storage of electric power in a vehicle is considered in the paper.

Abstract: This paper presents 66kv capacitor canceled fuse after the differential current protection setting calculation method, analyzes the application effect in practical engineering.The detailed calculation method has been analyzed in this paper, and the idea can be helpful in some cases

Abstract: Through the analysis of harmonics caused by transformer, capacitor, electromagnetic voltage transformer and other accident, harmonics is an important indicator of power quality, which has been included in the “pollution" of power grid is found. In order to understand the harmonic, this paper from the concept of quality of electric energy, and then gradually extended to the field of harmonics. This paper firstly introduces the various reasons and equipment may produce harmonic, Secondly, illustrate harm of harmonic to operation of transformers, capacitors, electromagnetic voltage transformers and other electrical equipment, let more people know and understand the relevant knowledge of the harmonic, In order to save technical force and provide scientific basis for future effective harmonic.

Abstract: Analyzing the active power loss of reactive power compensation device under normal reactive power output status and its influence factors and metering the active power loss of the reactor in the 500kV substation and the capacitor in the 220kV substation, concluding that the active power meter had the influencing factors of forward and reverse active and putting forward the assessment requirements for the running reactive power compensation device by analyzing the site calibration data of metering device.