scholarly journals Fluid Degradation Measurement Based on a Dual Coil Frequency Response Analysis

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4155 ◽  
Author(s):  
Jose M. Guerrero ◽  
Alejandro E. Castilla ◽  
José Ángel Sánchez-Fernández ◽  
Carlos A. Platero
Keyword(s):  
Single Phase ◽  
Salt Content ◽  
Water Concentration ◽  
Magnetic Core ◽  
Response Analysis ◽  
Fluid Composition ◽  
Synchronous Generators ◽  
Pollutant Concentrations ◽  
Healthy State ◽  
Degradation Measurement

Electrical industry uses oils for cooling and insulation of several machines, such as power transformers. In addition, it uses water for cooling some synchronous generators. To avoid malfunctions in these assets, fluid quality should be preserved. To contribute to this aim, a sensor that detects changes in fluid composition is presented. The designed sensor is like a single-phase transformer whose magnetic core is the fluid whose properties will be measured. The response of this device to a frequency sweep is recorded. Through a comparison between any measurement and a reference one corresponding to a healthy state, pollutants presence, such as water in oil or salt in water, can be measured. The performance of the sensor was analyzed through simulation. In addition, a prototype was built and tested measuring water concentration in oil and salt content in water. The correlation between pollutant concentration measured with the sensor and known pollutant concentrations is good.

scholarly journals Frequency Response Analysis Technique of Short Circuit Faults Detection in Photovoltaic Single-Phase Inverter Experimental Study

2021 ◽  
Vol 23 (4) ◽  
pp. 337-343
Author(s):  
Ouadfel Ghania ◽  
Houassine Hamza ◽  
Gacemi Abderzak ◽  
Bensaid Samir
Keyword(s):  
Frequency Response ◽  
Fault Location ◽  
Single Phase ◽  
Short Circuit ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Phase Inverter ◽  
Efficient Detection ◽  
Healthy State ◽  
Single Phase Inverter

The work proposed in this paper concerns the study of short circuit faults in a single-phase inverter dedicated to a photovoltaic application by applying the frequency response analysis (FRA) technique on this IGBT-based inverter controlled by a 18F2550 microcontroller, a prototype inverter was designed in the laboratory to be able to apply off-line short-circuit faults using an LRC meter. The FRA technique is based on the comparison of amplitude-frequency and phase-frequency signatures of healthy cases and fault situations. The experimental results also led to the conclusion that frequency response analysis can be used as an effective tool to detect faults in power electronic devices. This method allows for efficient detection and classification of faults with ease of implementation. For fault location, the fault branch is determined according to its position relative to its healthy state.

scholarly journals Frequency Response Modeling of Transformer Windings Utilizing the Equivalent Parameters of a Laminated Core

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2371 ◽  
Author(s):  
Konstanty Marek Gawrylczyk ◽  
Katarzyna Trela
Keyword(s):  
Frequency Response ◽  
Research Utilization ◽  
Power Transformer ◽  
Three Dimensional ◽  
Magnetic Core ◽  
Wide Frequency Range ◽  
Response Analysis ◽  
Response Curves ◽  
Transformer Winding ◽  
Response Modeling

The aim of the article is to present the method for modeling transformer winding inductance, taking into account the complex magnetic permeability and equivalent electric conductivity of the magnetic core. In the first stage of the research, a physical model of a 24-turn coil wound on the distribution transformer core was prepared. The Frequency Response Analysis (FRA) measurements of the coil were taken; then, the inductance of the coil as a function of frequency was calculated from the received frequency response curves. In the second stage, two-dimensional (2D) and three-dimensional (3D) computer models of the coil based on the finite element method (FEM) were established. In order to obtain the equivalent inductance characteristics of the winding modeled in 2D and 3D in a wide frequency range, the equality of the reluctance of the limbs and yokes in both models was assured. In the next stage of the research, utilization of the equivalent properties for the laminated magnetic material simulations was proposed. This outcome can be used to calculate the frequency response of the winding of the power transformer. The other obtained result is the method for modeling the resonance slope, which is visible on the inductance curve received from the FRA measurement.

scholarly journals The Short-Circuit Protections in Hybrid Systems with Low-Power Synchronous Generators

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 160
Author(s):  
Bartosz Rozegnał ◽  
Paweł Albrechtowicz ◽  
Dominik Mamcarz ◽  
Natalia Radwan-Pragłowska ◽  
Artur Cebula
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Electrical Systems ◽  
Protection Devices ◽  
Short Circuits ◽  
Damage Type

Single-phase short-circuits are most often faults in electrical systems. The analysis of this damage type is taken for backup power supply systems, from small power synchronous generators. For these hybrid installations, there is a need for standard protection devices, such as fuses or miniature circuit breaker (MCB) analysis. Experimental research mentioned that a typical protective apparatus in low-voltage installations, working correctly during supplying from the grid, does not guarantee fast off-switching, while short-circuits occur during supplication from the backup generator set. The analysis of single-phase short-circuits is executed both for current waveform character (including sub-transient and transient states) and the carried energy, to show the problems with the fuses and MCB usage, to protect circuits in installations fed in a hybrid way (from the grid and synchronous generator set).

scholarly journals Performance Characteristics of Single-Phase Self-Excited Induction Generators with an Iron Core of Various Non-Grain Oriented Electrical Sheets

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3166
Author(s):  
Krzysztof Makowski ◽  
Aleksander Leicht
Keyword(s):  
Steady State ◽  
Single Phase ◽  
Magnetic Core ◽  
Performance Characteristics ◽  
Iron Core ◽  
The Core ◽  
Induction Generators ◽  
Different Types ◽  
Load Characteristics ◽  
Steady State Performance

This paper deals with the computation of the performance characteristics of the single-phase self-excited induction generator by field–circuit method. It presents and compares previously unpublished results—self-excitation and no-load characteristics of the generator for different rotor speeds, and complete load steady-state performance characteristics for various types of the core materials. The discrepancies between the performance characteristics of the generator for the catalog’s magnetization curves of different types of electrical sheets and for an actual magnetic core of the generator for self-excitation transients and load steady-state are presented. The results may be useful for designing new constructions of single-phase self-excited induction generators.

scholarly journals A Numerical and Experimental Study on an Interconnected Metamaterial for Flexural Vibration Control Based on Modal Strain Energy

2021 ◽  
Vol 11 (10) ◽  
pp. 4530
Author(s):  
Hyun-Guk Kim ◽  
Onyu Jeon ◽  
Semyung Wang
Keyword(s):  
Strain Energy ◽  
Single Phase ◽  
Vibration Reduction ◽  
Flexural Vibration ◽  
Impact Testing ◽  
Response Analysis ◽  
3D Printer ◽  
Frequency Response Analysis ◽  
Modal Strain Energy ◽  
Bloch Mode

In this study, an interconnected metamaterial was proposed to suppress flexural vibration. The interconnected metamaterial can improve the manufacturing and installation processes in terms of convenience because it can be fabricated in the form of a modular multi-celled structure with a single-phase material. To evaluate the vibration reduction performance of the metamaterial, stopband analysis was performed, as it solves an iterative eigenvalue problem for the wave vector domain. In order to identify the Bloch mode that contributes to flexural vibration, a concept to extract the Bloch mode based on the modal strain energy was proposed. The vibration-reduction performance of the interconnected metamaterial was numerically verified by using a frequency-response analysis of the multi-celled structure. The interconnected metamaterial proposed in this study was fabricated by using a 3D printer. Finally, the vibration-reduction performance of the multi-celled structure was experimentally verified by using impact testing.

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