The document discusses the application of atmospheric correction factors during dielectric dry tests according to relevant IEC standards. It provides the following key details:
1) Atmospheric conditions like temperature, pressure and humidity affect the dielectric strength of external insulation and correction factors are used to convert test voltages to equivalent standard conditions.
2) The correction factor is calculated as the product of an air density factor and humidity factor. Test voltages are multiplied by the correction factor to obtain equivalent voltages under standard conditions.
3) Examples are given on calculating correction factors for a 36kV switchgear panel based on temperature, pressure and humidity measurements during testing. The calculated correction factor is applied to determine the adjusted impulse and power frequency test voltages.
Air flow through sudden expansion channelAli Jraisheh
The document summarizes a study of air flow through a two-dimensional channel with a sudden expansion. It describes the physical system of an air flow with different inlet velocity profiles through a channel that expands suddenly. It presents the mathematical model and governing equations used to model the laminar, incompressible flow. The numerical method and boundary conditions applied in the Fluent software are described. Key results are presented on streamlines, temperature contours, velocity and pressure profiles, and how heat transfer metrics vary with inlet velocity. It is concluded that vortices form after expansion and increase in size with velocity, while heat transfer depends on flow regimes and local conditions.
FAILURE CRITERIA FOR NON-BRITTLE MATERIALSAhmed Abdullah
- The document discusses several failure criteria theories for predicting failure in materials including brittle and ductile materials.
- Rankine's criteria and Mohr's criteria are based on maximum normal stresses and are applicable to brittle materials. Failure occurs when principal stresses reach ultimate tensile or compressive strengths.
- Maximum shear stress and von Mises criteria predict failure in ductile materials based on limiting shear stresses and distortion energy. Failure occurs when maximum shear stresses or distortion energy equals values from uniaxial tension tests.
1. Radiation can be described using both wave and particle theories, with photons traveling at the speed of light and having energy levels related to their frequency.
2. Thermal radiation emitted from surfaces is within the wavelength range of 10-7 to 10-4 m. The human eye can detect wavelengths from 3.8x10-7 to 7.6x10-7 m, known as visible radiation.
3. A blackbody is an idealized radiating surface that absorbs all radiation falling on it and reaches the maximum possible emissive power at each wavelength for a given temperature.
Stress concentration occurs where there is a discontinuity or abrupt change in geometry, such as a hole, notch, or crack. The theoretical stress concentration factor (Kt) is used to quantify the maximum stress at these locations compared to the nominal stress. Experimental methods like photoelasticity, brittle coatings, and strain gauges can be used to determine the actual stress concentration factor. The finite element method also allows modeling stress concentration by subdividing a component into small elements.
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
Experimental and Numerical Investigation of Shock/Turbulence Interaction by H...drboon
In the present paper, an experimental investigation has been carried out to observe the amplification of turbulence intensity after shock/turbulence interaction by hot-wire technique. The hot wires are installed in the wake of turbulent grids to measure turbulence fluctuations before and after the reflected shock interaction with turbulence. It is observed that the turbulence fluctuations for less open area of the grid plate are higher than the turbulence fluctuations for more open area of the grid plate. For numerical computations, grid plate of 49.5 % open area is used. The average longitudinal velocity line obtained from experimental velocity data simulates with numerical results properly and in some places, 5-7 % deviations are observed with numerical results. All the simulation results indicate that the present code with turbulence model is working properly. The substantial amplification of pressure fluctuations obtained from experiment is observed after interaction. The dissipation rate of turbulent kinetic energy (TKE) and the levels of length scales are determined numerically. It is observed that the dissipation rate of TKE and the levels of length scales decrease after shock/turbulence interaction.
Experiment on single-mode feedback control of oscillatory thermocapillary con...IJERA Editor
Feedback control was carried out on nonlinear thermocapillary convections in a half-zone liquid bridge of a high
Prandtl number fluid under normal gravity. In the liquid bridge, the convection changed from a two-dimensional
steady flow to a three-dimensional oscillatory flow at a critical temperature difference. Feedback control was
realized by locally modifying the free surface temperature using local temperature measured at different
positions. The present study aims to confirm whether the control method can effectively suppress oscillatory
flows with every modal structure. Consequently, the control was theoretically verified to be effective for
oscillatory flows with every modal structure in a high Marangoni number range.
This document discusses the treatment of compressible flow in computational fluid dynamics (CFD). It covers the basics of compressible flow including conservation laws, the governing equations in conservation form, and the wave theory known as the CFL condition. It also discusses schemes for solving the equations, including flux vector splitting schemes, Roe averaged schemes, and AUSM schemes. The document emphasizes that compressible flow equations are hyperbolic and describes how characteristics and eigenvalues relate to the equation types.
Air flow through sudden expansion channelAli Jraisheh
The document summarizes a study of air flow through a two-dimensional channel with a sudden expansion. It describes the physical system of an air flow with different inlet velocity profiles through a channel that expands suddenly. It presents the mathematical model and governing equations used to model the laminar, incompressible flow. The numerical method and boundary conditions applied in the Fluent software are described. Key results are presented on streamlines, temperature contours, velocity and pressure profiles, and how heat transfer metrics vary with inlet velocity. It is concluded that vortices form after expansion and increase in size with velocity, while heat transfer depends on flow regimes and local conditions.
FAILURE CRITERIA FOR NON-BRITTLE MATERIALSAhmed Abdullah
- The document discusses several failure criteria theories for predicting failure in materials including brittle and ductile materials.
- Rankine's criteria and Mohr's criteria are based on maximum normal stresses and are applicable to brittle materials. Failure occurs when principal stresses reach ultimate tensile or compressive strengths.
- Maximum shear stress and von Mises criteria predict failure in ductile materials based on limiting shear stresses and distortion energy. Failure occurs when maximum shear stresses or distortion energy equals values from uniaxial tension tests.
1. Radiation can be described using both wave and particle theories, with photons traveling at the speed of light and having energy levels related to their frequency.
2. Thermal radiation emitted from surfaces is within the wavelength range of 10-7 to 10-4 m. The human eye can detect wavelengths from 3.8x10-7 to 7.6x10-7 m, known as visible radiation.
3. A blackbody is an idealized radiating surface that absorbs all radiation falling on it and reaches the maximum possible emissive power at each wavelength for a given temperature.
Stress concentration occurs where there is a discontinuity or abrupt change in geometry, such as a hole, notch, or crack. The theoretical stress concentration factor (Kt) is used to quantify the maximum stress at these locations compared to the nominal stress. Experimental methods like photoelasticity, brittle coatings, and strain gauges can be used to determine the actual stress concentration factor. The finite element method also allows modeling stress concentration by subdividing a component into small elements.
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
Experimental and Numerical Investigation of Shock/Turbulence Interaction by H...drboon
In the present paper, an experimental investigation has been carried out to observe the amplification of turbulence intensity after shock/turbulence interaction by hot-wire technique. The hot wires are installed in the wake of turbulent grids to measure turbulence fluctuations before and after the reflected shock interaction with turbulence. It is observed that the turbulence fluctuations for less open area of the grid plate are higher than the turbulence fluctuations for more open area of the grid plate. For numerical computations, grid plate of 49.5 % open area is used. The average longitudinal velocity line obtained from experimental velocity data simulates with numerical results properly and in some places, 5-7 % deviations are observed with numerical results. All the simulation results indicate that the present code with turbulence model is working properly. The substantial amplification of pressure fluctuations obtained from experiment is observed after interaction. The dissipation rate of turbulent kinetic energy (TKE) and the levels of length scales are determined numerically. It is observed that the dissipation rate of TKE and the levels of length scales decrease after shock/turbulence interaction.
Experiment on single-mode feedback control of oscillatory thermocapillary con...IJERA Editor
Feedback control was carried out on nonlinear thermocapillary convections in a half-zone liquid bridge of a high
Prandtl number fluid under normal gravity. In the liquid bridge, the convection changed from a two-dimensional
steady flow to a three-dimensional oscillatory flow at a critical temperature difference. Feedback control was
realized by locally modifying the free surface temperature using local temperature measured at different
positions. The present study aims to confirm whether the control method can effectively suppress oscillatory
flows with every modal structure. Consequently, the control was theoretically verified to be effective for
oscillatory flows with every modal structure in a high Marangoni number range.
This document discusses the treatment of compressible flow in computational fluid dynamics (CFD). It covers the basics of compressible flow including conservation laws, the governing equations in conservation form, and the wave theory known as the CFL condition. It also discusses schemes for solving the equations, including flux vector splitting schemes, Roe averaged schemes, and AUSM schemes. The document emphasizes that compressible flow equations are hyperbolic and describes how characteristics and eigenvalues relate to the equation types.
HVE UNIT V HIGH VOLTAGES TESTING AND INSULATION COORDINATION.pptxMuthuKumar158260
This document discusses high voltage testing and insulation coordination. It defines key terms related to high voltage testing such as disruptive discharge voltage, withstand voltage, and flashover voltage. It then describes various types of high voltage tests that are performed on electrical equipment, including power frequency tests, impulse tests, and pollution testing. Power frequency tests involve dry and wet flashover tests and withstand tests. Impulse tests include impulse withstand voltage tests and impulse flashover tests.
AC High voltage Air Break Disconnector Switch Routine Test According to IEC 6...Ali Sepehri
AC High voltage Air Break Disconnector Switch Routine Test According to IEC 62271-102 Standard
Article 9(09.10.2018) direct link: https://lnkd.in/gX_aVqq
This document provides instructions for performing an experiment on the Hall Effect using a PASCO SE-7260 Hall Effect Apparatus. It includes an equipment list, safety information, descriptions of the apparatus and hardware setup, as well as background theory on the Hall Effect. The experiment measures the Hall voltage generated in a semiconductor under an applied magnetic field to determine properties of the charge carriers in the material.
The document discusses partial discharge (PD) techniques for measuring the condition of aging high voltage and medium voltage switchgear. It provides 3 key points:
1) PD activity is a major cause of long-term degradation of insulation in switchgear. Measuring PD can detect defects before complete failure and allow targeted maintenance.
2) The latest PD measuring instruments use dual sensors to detect both surface and internal PD non-intrusively. Measurements of PD pulses externally can indicate the insulation condition.
3) Condition-based maintenance using PD measurements can improve safety, reliability and lower costs compared to time-based maintenance. Utilities like SP Powergrid in Singapore have seen significant benefits including reduced outages and savings of
Partial Discharge Analysis in High Voltage Current TransformersIRJESJOURNAL
ABSTRACT: In High Voltage (HV) electrical power systems, variety of materials (solid, liquid and gaseous) is used for insulation purpose to protect the incipient failure in Current Transformers. Most of insulating materials are not perfect in all respect and contains always some impurities. The presence of air bubble is one of such impurities in insulating materials and highly undesirable for such type of insulation which causes a local weak zone inside the insulator. Due to the high voltage stress the weak zone inside the insulator causes the partial discharge (PD) and finally the insulation properties of such materials is enormously degrades its quality. In this work, the simulation of PD activity due to presence of a small cylindrical void inside the solid insulation material of high voltage power equipment is analyzed with the MATLAB Simulink platform.
measurement of high voltage and high currents mukund mukund.m
The document discusses various techniques for measuring high voltages and currents, including:
- Sphere gap voltmeters, which measure sparkover voltage between conducting spheres;
- Electrostatic voltmeters, which measure the attraction force between charged parallel plates;
- Generating voltmeters, which use a variable capacitor to generate a current proportional to input voltage.
Peak reading voltmeters are also summarized, which use a capacitor to measure the peak voltage of AC waveforms. The document provides details on the principles, construction, advantages, and limitations of these different high voltage and current measurement methods.
High voltage testing is important for ensuring insulation can withstand transient overvoltages. There are several types of high voltage tests:
(1) Power frequency tests include dry and wet flashover tests and withstand tests to determine insulation withstand capability under normal and wet conditions.
(2) Impulse tests involve applying standard impulse voltages to determine insulation withstand under transient overvoltages like lightning.
(3) Partial discharge testing locates internal insulation weaknesses by detecting and measuring electrical discharges within insulation.
1) Tan delta testing uses a very low frequency AC voltage to measure the dissipation factor of insulation to determine its quality and condition. A higher loss angle indicates more contamination.
2) The cable or winding is disconnected and the test voltage is applied and increased in steps while tan delta measurements are taken. A straight trend line indicates healthy insulation while a rising line indicates contamination.
3) Routine maintenance of bushings includes inspecting the porcelain for cracks, metal parts for corrosion, oil levels, and cleaning surface contamination which can cause flashovers. Leaks should be repaired to prevent moisture issues.
SSC JE Measurements - wifistudy (1).pdfVibhugoyal6
This document provides a crash course on the SSC-JE exam, including two sample questions:
1. A multiple choice question with four answer options about sources of energy.
2. A matching question with four items to be matched to letters about load curves, tidal power generation, non-conventional power generation methods, and solar cells.
It then discusses error analysis in measurement and types of errors like random error, systematic error, gross error, environmental error, instrumental error, observational error, and limiting error. Composite errors in addition, multiplication, and powers are also covered.
This document provides information about transformer tests conducted at BEST Balıkesir Transformer Factory laboratories. It describes routine tests like winding resistance measurement, voltage ratio measurement and phase checking, as well as type tests and special tests. The routine tests section explains test procedures and equipment for various tests done on all transformers produced. These include impedance measurement, no-load loss tests, and tap changer tests. Type and special tests involve temperature rise testing, lightning impulse testing, and other advanced analyses. Laboratory equipment for performing over a dozen transformer tests is also listed.
Dielectric Spectroscopy in Time and Frequency DomainGirish Gupta
This presentation describes the basics and technicalities of Dielectric Spectroscopy in both time and frequency domain. IT also includes the procedure and results involved in Dielectric Spectroscopy on different dielectrics.
This document discusses the operation and maintenance of air insulated substations (AIS). It describes the key components of an AIS including surge arresters, instrument transformers, isolators, circuit breakers and their functions. It provides details on maintenance activities for each component such as cleaning, tightening connections, insulation resistance testing, contact resistance checking and gas/oil pressure monitoring. The conclusions emphasize the importance of maintenance to keep substation equipment in acceptable working condition through various strategies like preventive maintenance and condition monitoring.
This document provides an overview of modeling and simulation approaches for an alkaline water electrolyzer. It describes the electrolysis process and reaction equations. A thermodynamic model is presented that calculates the reversible voltage and thermoneutral potential from changes in Gibbs free energy and enthalpy with temperature. The document also discusses sources of cell overpotential including activation, ohmic resistance, and gas bubble formation that increase the actual operating voltage above the minimum reversible value. Flow rates of hydrogen and oxygen produced are calculated from Faraday's laws using current and Faraday efficiency.
This document discusses testing of transformers. It provides an overview of transformers and their functions in transmission and distribution of electrical energy. It then describes various routine, type, and special tests performed on transformers, including winding resistance measurement, voltage ratio measurement, no-load loss measurement, load loss measurement, insulation resistance measurement, and dielectric tests. It also discusses short-circuit testing procedures and criteria. Temperature rise testing and its limits are also summarized.
Thermodynamics analysis of diffusion in spark plasma sintering welding Cr3C2 ...AliFeiz3
In the thermodynamics analysis of diffusion in spark plasma sintering (SPS) welding of Cr3C2 (chromium carbide) and Ni (nickel), various thermodynamic principles and concepts are applied to understand the heat and mass transfer processes involved. SPS is a specialized technique used to consolidate powders into dense materials using pulsed direct current and pressure.
The focus of the analysis is on diffusion, which refers to the movement of atoms or molecules from regions of high concentration to regions of low concentration. Diffusion plays a crucial role in the welding process of Cr3C2 and Ni, as it influences the formation of interfacial bonds between the particles.
Thermodynamic analysis involves examining the energy changes and driving forces associated with diffusion during the SPS welding process. This analysis aims to determine the factors that govern the diffusion process, such as temperature, pressure, concentration gradients, and material properties.
By studying the thermodynamics of diffusion, researchers can gain insights into the kinetics and mechanisms of atomic or molecular movement, as well as the resulting microstructural changes and bonding at the interfaces between Cr3C2 and Ni particles. This knowledge helps optimize the SPS welding process parameters and improve the quality and properties of the welded material.
Key aspects explored in the thermodynamics analysis may include heat transfer mechanisms, such as Joule heating during SPS, and mass transfer phenomena, such as atomic diffusion of Cr, C, and Ni species. The analysis may also consider thermodynamic properties of the materials involved, such as melting points, phase diagrams, and chemical potential gradients, to understand the driving forces for diffusion.
Overall, the thermodynamics analysis of diffusion in spark plasma sintering welding of Cr3C2 and Ni provides a deeper understanding of the fundamental principles governing the welding process, aiding in the development of advanced materials with enhanced properties and performance.
This document describes using active disturbance rejection control (ADRC) for controlling a single-stage photovoltaic system connected to the electrical grid. It compares ADRC to the conventional perturb and observe (P&O) control method. ADRC combined with incremental conductance (ADRC-IC) is used for maximum power point tracking (MPPT) control. ADRC is also used to control the inverter to regulate the DC bus voltage and ensure unity power factor injection into the grid. The system aims to maximize power extraction from the PV array and regulate power injection into the grid with low harmonics.
This document provides an overview of switchgears and protective devices used in power systems. It discusses substations, faults and abnormal conditions, fault calculations, the fault clearing process, protective relaying, and power system stability. Protective devices like circuit breakers, fuses, and relays are installed at different voltage levels and switching points to ensure reliable power supply and isolate faults. Substations are used to change voltage levels and switch equipment in and out of the system. Faults can occur due to insulation failures, breaks, or mechanical issues and their severity is estimated through fault current calculations. Relays detect faults and signal circuit breakers to clear the fault and restore the system. Stability is maintained by keeping the rotor and st
This document provides instructions for testing the short-circuit impedance and load loss of transformers. The short-circuit voltage and loss show the transformer's performance and are important specifications. To measure: the HV windings are supplied while the LV windings are short-circuited, applying a current close to the rated current. Voltage, current and losses are measured in each phase. Losses are corrected to a reference temperature and separated into DC and AC components. Measurements are made at rated, maximum and minimum ranges.
DESIGN OF A PROGRAMMABLE LOW POWER LOW DROP-OUT REGULATORVLSICS Design
A low power programmable low drop-out regulator capable of providing 1V output has been proposed. The
regulator requires a supply voltage of 1.2V and works in the temperature range of -40 to 125 °C in nominal
corner (i.e, normal doping for PMOS and NMOS Field Effect Transistors), yielding a load regulation of
3%. The output voltage level is controlled externally by means of 2 1-bit control signals. The circuit
provides a DC gain of 30 dB and a maximum DC Power Supply Rejection Ratio of -35 dB and a worst case
PSRR of -20 dB. Power dissipation in the load is nearly 100 μW
This document summarizes a project on automatic load frequency control and automatic load dispatch presented by four students at Madan Mohan Malaviya University of Technology, Gorakhpur. It introduces load frequency control and discusses its objectives to maintain uniform frequency and control tie-line power interchange. It then analyzes the response of load frequency control for an isolated single area power system and a two area interconnected power system, both with and without control. The conclusion states that controllers keep generators operating near a normal state with minimal deviations, and simulation results show the proposed approach ensures viable system evolution despite load and failure changes.
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HVE UNIT V HIGH VOLTAGES TESTING AND INSULATION COORDINATION.pptxMuthuKumar158260
This document discusses high voltage testing and insulation coordination. It defines key terms related to high voltage testing such as disruptive discharge voltage, withstand voltage, and flashover voltage. It then describes various types of high voltage tests that are performed on electrical equipment, including power frequency tests, impulse tests, and pollution testing. Power frequency tests involve dry and wet flashover tests and withstand tests. Impulse tests include impulse withstand voltage tests and impulse flashover tests.
AC High voltage Air Break Disconnector Switch Routine Test According to IEC 6...Ali Sepehri
AC High voltage Air Break Disconnector Switch Routine Test According to IEC 62271-102 Standard
Article 9(09.10.2018) direct link: https://lnkd.in/gX_aVqq
This document provides instructions for performing an experiment on the Hall Effect using a PASCO SE-7260 Hall Effect Apparatus. It includes an equipment list, safety information, descriptions of the apparatus and hardware setup, as well as background theory on the Hall Effect. The experiment measures the Hall voltage generated in a semiconductor under an applied magnetic field to determine properties of the charge carriers in the material.
The document discusses partial discharge (PD) techniques for measuring the condition of aging high voltage and medium voltage switchgear. It provides 3 key points:
1) PD activity is a major cause of long-term degradation of insulation in switchgear. Measuring PD can detect defects before complete failure and allow targeted maintenance.
2) The latest PD measuring instruments use dual sensors to detect both surface and internal PD non-intrusively. Measurements of PD pulses externally can indicate the insulation condition.
3) Condition-based maintenance using PD measurements can improve safety, reliability and lower costs compared to time-based maintenance. Utilities like SP Powergrid in Singapore have seen significant benefits including reduced outages and savings of
Partial Discharge Analysis in High Voltage Current TransformersIRJESJOURNAL
ABSTRACT: In High Voltage (HV) electrical power systems, variety of materials (solid, liquid and gaseous) is used for insulation purpose to protect the incipient failure in Current Transformers. Most of insulating materials are not perfect in all respect and contains always some impurities. The presence of air bubble is one of such impurities in insulating materials and highly undesirable for such type of insulation which causes a local weak zone inside the insulator. Due to the high voltage stress the weak zone inside the insulator causes the partial discharge (PD) and finally the insulation properties of such materials is enormously degrades its quality. In this work, the simulation of PD activity due to presence of a small cylindrical void inside the solid insulation material of high voltage power equipment is analyzed with the MATLAB Simulink platform.
measurement of high voltage and high currents mukund mukund.m
The document discusses various techniques for measuring high voltages and currents, including:
- Sphere gap voltmeters, which measure sparkover voltage between conducting spheres;
- Electrostatic voltmeters, which measure the attraction force between charged parallel plates;
- Generating voltmeters, which use a variable capacitor to generate a current proportional to input voltage.
Peak reading voltmeters are also summarized, which use a capacitor to measure the peak voltage of AC waveforms. The document provides details on the principles, construction, advantages, and limitations of these different high voltage and current measurement methods.
High voltage testing is important for ensuring insulation can withstand transient overvoltages. There are several types of high voltage tests:
(1) Power frequency tests include dry and wet flashover tests and withstand tests to determine insulation withstand capability under normal and wet conditions.
(2) Impulse tests involve applying standard impulse voltages to determine insulation withstand under transient overvoltages like lightning.
(3) Partial discharge testing locates internal insulation weaknesses by detecting and measuring electrical discharges within insulation.
1) Tan delta testing uses a very low frequency AC voltage to measure the dissipation factor of insulation to determine its quality and condition. A higher loss angle indicates more contamination.
2) The cable or winding is disconnected and the test voltage is applied and increased in steps while tan delta measurements are taken. A straight trend line indicates healthy insulation while a rising line indicates contamination.
3) Routine maintenance of bushings includes inspecting the porcelain for cracks, metal parts for corrosion, oil levels, and cleaning surface contamination which can cause flashovers. Leaks should be repaired to prevent moisture issues.
SSC JE Measurements - wifistudy (1).pdfVibhugoyal6
This document provides a crash course on the SSC-JE exam, including two sample questions:
1. A multiple choice question with four answer options about sources of energy.
2. A matching question with four items to be matched to letters about load curves, tidal power generation, non-conventional power generation methods, and solar cells.
It then discusses error analysis in measurement and types of errors like random error, systematic error, gross error, environmental error, instrumental error, observational error, and limiting error. Composite errors in addition, multiplication, and powers are also covered.
This document provides information about transformer tests conducted at BEST Balıkesir Transformer Factory laboratories. It describes routine tests like winding resistance measurement, voltage ratio measurement and phase checking, as well as type tests and special tests. The routine tests section explains test procedures and equipment for various tests done on all transformers produced. These include impedance measurement, no-load loss tests, and tap changer tests. Type and special tests involve temperature rise testing, lightning impulse testing, and other advanced analyses. Laboratory equipment for performing over a dozen transformer tests is also listed.
Dielectric Spectroscopy in Time and Frequency DomainGirish Gupta
This presentation describes the basics and technicalities of Dielectric Spectroscopy in both time and frequency domain. IT also includes the procedure and results involved in Dielectric Spectroscopy on different dielectrics.
This document discusses the operation and maintenance of air insulated substations (AIS). It describes the key components of an AIS including surge arresters, instrument transformers, isolators, circuit breakers and their functions. It provides details on maintenance activities for each component such as cleaning, tightening connections, insulation resistance testing, contact resistance checking and gas/oil pressure monitoring. The conclusions emphasize the importance of maintenance to keep substation equipment in acceptable working condition through various strategies like preventive maintenance and condition monitoring.
This document provides an overview of modeling and simulation approaches for an alkaline water electrolyzer. It describes the electrolysis process and reaction equations. A thermodynamic model is presented that calculates the reversible voltage and thermoneutral potential from changes in Gibbs free energy and enthalpy with temperature. The document also discusses sources of cell overpotential including activation, ohmic resistance, and gas bubble formation that increase the actual operating voltage above the minimum reversible value. Flow rates of hydrogen and oxygen produced are calculated from Faraday's laws using current and Faraday efficiency.
This document discusses testing of transformers. It provides an overview of transformers and their functions in transmission and distribution of electrical energy. It then describes various routine, type, and special tests performed on transformers, including winding resistance measurement, voltage ratio measurement, no-load loss measurement, load loss measurement, insulation resistance measurement, and dielectric tests. It also discusses short-circuit testing procedures and criteria. Temperature rise testing and its limits are also summarized.
Thermodynamics analysis of diffusion in spark plasma sintering welding Cr3C2 ...AliFeiz3
In the thermodynamics analysis of diffusion in spark plasma sintering (SPS) welding of Cr3C2 (chromium carbide) and Ni (nickel), various thermodynamic principles and concepts are applied to understand the heat and mass transfer processes involved. SPS is a specialized technique used to consolidate powders into dense materials using pulsed direct current and pressure.
The focus of the analysis is on diffusion, which refers to the movement of atoms or molecules from regions of high concentration to regions of low concentration. Diffusion plays a crucial role in the welding process of Cr3C2 and Ni, as it influences the formation of interfacial bonds between the particles.
Thermodynamic analysis involves examining the energy changes and driving forces associated with diffusion during the SPS welding process. This analysis aims to determine the factors that govern the diffusion process, such as temperature, pressure, concentration gradients, and material properties.
By studying the thermodynamics of diffusion, researchers can gain insights into the kinetics and mechanisms of atomic or molecular movement, as well as the resulting microstructural changes and bonding at the interfaces between Cr3C2 and Ni particles. This knowledge helps optimize the SPS welding process parameters and improve the quality and properties of the welded material.
Key aspects explored in the thermodynamics analysis may include heat transfer mechanisms, such as Joule heating during SPS, and mass transfer phenomena, such as atomic diffusion of Cr, C, and Ni species. The analysis may also consider thermodynamic properties of the materials involved, such as melting points, phase diagrams, and chemical potential gradients, to understand the driving forces for diffusion.
Overall, the thermodynamics analysis of diffusion in spark plasma sintering welding of Cr3C2 and Ni provides a deeper understanding of the fundamental principles governing the welding process, aiding in the development of advanced materials with enhanced properties and performance.
This document describes using active disturbance rejection control (ADRC) for controlling a single-stage photovoltaic system connected to the electrical grid. It compares ADRC to the conventional perturb and observe (P&O) control method. ADRC combined with incremental conductance (ADRC-IC) is used for maximum power point tracking (MPPT) control. ADRC is also used to control the inverter to regulate the DC bus voltage and ensure unity power factor injection into the grid. The system aims to maximize power extraction from the PV array and regulate power injection into the grid with low harmonics.
This document provides an overview of switchgears and protective devices used in power systems. It discusses substations, faults and abnormal conditions, fault calculations, the fault clearing process, protective relaying, and power system stability. Protective devices like circuit breakers, fuses, and relays are installed at different voltage levels and switching points to ensure reliable power supply and isolate faults. Substations are used to change voltage levels and switch equipment in and out of the system. Faults can occur due to insulation failures, breaks, or mechanical issues and their severity is estimated through fault current calculations. Relays detect faults and signal circuit breakers to clear the fault and restore the system. Stability is maintained by keeping the rotor and st
This document provides instructions for testing the short-circuit impedance and load loss of transformers. The short-circuit voltage and loss show the transformer's performance and are important specifications. To measure: the HV windings are supplied while the LV windings are short-circuited, applying a current close to the rated current. Voltage, current and losses are measured in each phase. Losses are corrected to a reference temperature and separated into DC and AC components. Measurements are made at rated, maximum and minimum ranges.
DESIGN OF A PROGRAMMABLE LOW POWER LOW DROP-OUT REGULATORVLSICS Design
A low power programmable low drop-out regulator capable of providing 1V output has been proposed. The
regulator requires a supply voltage of 1.2V and works in the temperature range of -40 to 125 °C in nominal
corner (i.e, normal doping for PMOS and NMOS Field Effect Transistors), yielding a load regulation of
3%. The output voltage level is controlled externally by means of 2 1-bit control signals. The circuit
provides a DC gain of 30 dB and a maximum DC Power Supply Rejection Ratio of -35 dB and a worst case
PSRR of -20 dB. Power dissipation in the load is nearly 100 μW
This document summarizes a project on automatic load frequency control and automatic load dispatch presented by four students at Madan Mohan Malaviya University of Technology, Gorakhpur. It introduces load frequency control and discusses its objectives to maintain uniform frequency and control tie-line power interchange. It then analyzes the response of load frequency control for an isolated single area power system and a two area interconnected power system, both with and without control. The conclusion states that controllers keep generators operating near a normal state with minimal deviations, and simulation results show the proposed approach ensures viable system evolution despite load and failure changes.
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