scholarly journals Statistical Analysis of AC Dielectric Strength of Natural Ester-Based ZnO Nanofluids

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 99
Author(s):  
Hidir Duzkaya ◽  
Abderrahmane Beroual
Keyword(s):  
Energy Demand ◽  
Measurement Data ◽  
Dielectric Strength ◽  
Electrode System ◽  
Distribution Functions ◽  
Environmental Concerns ◽  
Mineral Oils ◽  
Zno Nanofluids ◽  
Electrical Components ◽  
Natural Ester

Due to environmental concerns and increased energy demand, natural esters are among the alternatives to mineral oils in transformers. This study examines the electrical behavior of natural ester-based ZnO nanofluids at different concentrations in the range of 0.05–0.4 g/L. AC breakdown voltages are measured in a horizontally positioned sphere–sphere electrode system according to IEC 60156 specifications. The measurement data are analyzed using Weibull and normal distribution functions. Breakdown voltages with 1%, 10% and 50% probability are also estimated, these probabilities being of great interest for the design of power electrical components. Experimental results show that AC breakdown voltage increases with the concentration of ZnO nanoparticles, except for the concentration of 0.05 and 0.4 g/L of ZnO. Moreover, breakdown voltages at 1% and 10% probability increase by 22.7% and 13.2% when adding 0.1 g/L ZnO to natural ester, respectively.

scholarly journals Investigation of Survival/Hazard Rate of Natural Ester Treated with Al2O3 Nanoparticle for Power Transformer Liquid Dielectric

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1510
Author(s):  
Raymon Antony Raj ◽  
Ravi Samikannu ◽  
Abid Yahya ◽  
Modisa Mosalaosi
Keyword(s):  
Survival Rate ◽  
Hazard Rate ◽  
Power Transformer ◽  
Mineral Oil ◽  
Interpolation Polynomial ◽  
Distribution Functions ◽  
Flash Fire ◽  
Predicted Values ◽  
Natural Ester ◽  
Electrical Apparatus

Increasing usage of petroleum-based insulating oils in electrical apparatus has led to increase in pollution and, at the same time, the oils adversely affect the life of electrical apparatus. This increases the demand of Mineral Oil (MO), which is on the verge of extinction and leads to conducting tests on natural esters. This work discusses dielectric endurance of Marula Oil (MRO), a natural ester modified using Conductive Nano Particle (CNP) to replace petroleum-based dielectric oils for power transformer applications. The Al2O3 is a CNP that has a melting point of 2072 °C and a low charge relaxation time that allows time to quench free electrons during electrical discharge. Al2O3 is blended with the MRO and Mineral Oil (MO) in different concentrations. The measured dielectric properties are transformed into mathematical equations using the Lagrange interpolation polynomial functions and compared with the predicted values either using Gaussian or Fourier distribution functions. Addition of Al2O3 indicates that 0.75 g/L in MRO has an 80% survival rate and 20% hazard rate compared to MO which has 50% survival rate and 50% hazard rate. Considering the measured or interpolated values and the predicted values, they are used to identify the MRO and MO’s optimum concentration produces better results. The test result confirms the enhancement of the breakdown voltage up to 64%, kinematic viscosity is lowered by up to 40% at 110 °C, and flash/fire points of MRO after Al2O3 treatment enhanced to 14% and 23%. Hence the endurance of Al2O3 in MRO proves to be effective against electrical, physical and thermal stress.

A review on tribological performance of ionic liquids as additives to bio lubricants

2020 ◽  
pp. 135065012097380
Author(s):  
Tehreem Naveed ◽  
Rehan Zahid ◽  
Riaz Ahmad Mufti ◽  
Muhammad Waqas ◽  
Muhammad Talha Hanif
Keyword(s):  
Ionic Liquids ◽  
Friction And Wear ◽  
Combustion Engine ◽  
Tribological Performance ◽  
Environmental Concerns ◽  
Published Data ◽  
Oil Reserves ◽  
Mineral Oils ◽  
The Past ◽  
Interacting Surfaces

All the moving components in an internal combustion engine require a lubricant that allows smooth sliding and/or rolling of interacting surfaces. Lubricant not only minimizes the friction and wear but also dissipates the heat generated due to friction and removes debris from the area of contact. Environmental concerns, decreasing mineral oil reserves and difficult disposal of nonbiodegradable conventional lubricants have urged the researchers to shift towards environmental-friendly lubricants. Number of tribological studies carried out in the past have proved that ionic liquid-based bio-lubricants are sustainable and biodegradable alternative to mineral oils. This paper presents a brief review of properties of ionic liquids and their ability to reduce friction and wear between the interacting surfaces. Tribological performance and compatibility of ionic liquids with various base-oils have been compared under boundary lubrication. The results reveal that phosphonium-based ionic liquids namely tetra-decyl tri-hexyl phosphonium bis(2,4,4-trimethylpentyl) phosphinate (P66614)i(C8)2PO2 and tri-hexyl tetra-decyl phosphonium bis(2-ethylhexyl) phosphate (P-DEHP) are more suitable for tribological applications. Since, ionic liquids can be tailored according to the application and millions of combinations are possible therefore, there is a need to summarize the published data in a more systematic and logical way.

scholarly journals Statistical Analysis of Bistatic Radar Ground Clutter for Different German Rural Environments

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3311
Author(s):  
Michael Kohler ◽  
Daniel W. O’Hagan ◽  
Matthias Weiss ◽  
David Wegner ◽  
Josef Worms ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Measurement Data ◽  
Distribution Functions ◽  
Statistical Properties ◽  
Cumulative Distribution ◽  
Center Frequency ◽  
Rural Environment ◽  
Bistatic Radar ◽  
Ground Clutter ◽  
Rural Environments

This article presents the statistical analysis of bistatic radar rural ground clutter for different terrain types under low grazing angles. Compared to most state-of-the-art analysis, we present country-specific clutter analysis for subgroups of rural environments rather than for the rural environment as a whole. Therefore, the rural environment analysis is divided into four dominant subgroup terrain types, namely fields with low vegetation, fields with high vegetation, plantations of small trees and forest environments representing a typical rural German environment. We will present the results for both the summer and the winter vegetation. Therefore, bistatic measurement campaigns have been carried out during the summer 2019 and the winter of 2019/20 in the aforementioned four different rural terrain types. The measurements were performed in the radar relevant X-band at a center frequency of 8.85 GHz and over a bandwidth of 100 MHz according to available transmit permission. The distinction of the rural terrain into different subgroups enables a more precise and accurate clutter analysis and modeling of the statistical properties as will be shown in the presented results. The statistical properties are derived from the calculated clutter amplitudes probability density functions and corresponding cumulative distribution functions for each of the four terrain types and the corresponding season. The data basis for the clutter analysis are the processed range-Doppler maps from the bistatic radar measurements. According to the authors’ current knowledge, a similar investigation based on real bistatic radar measurement data with the division into terrain subgroups has not yet been carried out and published for a German rural environment.

scholarly journals Green Gas for Grid as an Eco-Friendly Alternative Insulation Gas to SF6: A Review

2020 ◽  
Vol 10 (7) ◽  
pp. 2526 ◽  
Author(s):  
Baofeng Pan ◽  
Guoming Wang ◽  
Huimin Shi ◽  
Jiahua Shen ◽  
Hong-Keun Ji ◽  
...  
Keyword(s):  
Sulfur Hexafluoride ◽  
Heat Dissipation ◽  
Circuit Breaker ◽  
Chemical Properties ◽  
Electric Power Industry ◽  
Dielectric Strength ◽  
Environmental Concerns ◽  
Current Test ◽  
Lightning Impulse ◽  
Liquefaction Temperature

This paper deals with a review of the state-of-the-art performance investigations of green gas for grid (g3) gas, which is an emerging eco-friendly alternative insulation gas for sulfur hexafluoride (SF6) that will be used in gas-insulated power facilities for reducing environmental concerns. The required physical and chemical properties of insulation gas for high-voltage applications are discussed, including dielectric strength, arc-quenching capability, heat dissipation, boiling point, vapor pressure, compatibility, and environmental and safety requirements. Current studies and results on AC, DC, and lightning impulse breakdown voltage, as well as the partial discharge of g3 gas, are provided, which indicate an equivalent dielectric strength of g3 gas with SF6 after a proper design change or an increase in gas pressure. The switching bus-transfer current test, temperature rise test, and liquefaction temperature calculation also verify the possibility of replacing SF6 with g3 gas. In addition, the use of g3 gas significantly reduces theabovementioned environmental concerns in terms of global warming potential and atmosphere lifetime. In recent years, g3 gas-insulated power facilities, including switchgear, transmission line, circuit breaker, and transformer, have been commercially available in the electric power industry.

Dielectric strength of mineral oils

1935 ◽  
Vol 54 (1) ◽  
pp. 50-55 ◽  
Author(s):  
F. M. Clark
Keyword(s):  
Dielectric Strength ◽  
Mineral Oils

Fillers in Electrical Papers for Power Transformers

2014 ◽  
Vol 875-877 ◽  
pp. 335-340 ◽  
Author(s):  
Primo Alberto Calva ◽  
Aarón Israel Díaz ◽  
Hugo Martínez Gutierrez
Keyword(s):  
Electrical Properties ◽  
Theoretical Analysis ◽  
Structural Parameters ◽  
Dielectric Strength ◽  
Mineral Oil ◽  
Dielectric Behavior ◽  
Power Transformers ◽  
Mechanical Resistance ◽  
Kraft Paper ◽  
Natural Ester

The electric papers have a wide variety of uses like in transformers, cables and power capacitors. Each application involves different requirements related to its mechanical and electric properties. The kraft is the dielectric paper most used due its high mechanical resistance and a dielectric strength of around 5 kV/mm that is increased up to 30 kV/mm when is impregnated with mineral oil and typically has a density of 0.7, nevertheless continuous improvements in the design, for example, of power transformers raise the need to improve its electrical properties particularly those related to its relative permittivity. In this article, structural parameters such as distribution and pore size of kraft paper and theoretical analysis for possible addition of nanofillers to improve their dielectric behavior are reported. A possible and better criterion for designing transformers can be the employment of kraft paper nano-inserted with 5 % of TiO2 or BaTiO3 stew in mineral oil and immersed in natural ester liquid.

Analyzing wind speed data and wind power density of Tetouan city in Morocco by adjustment to Weibull and Rayleigh distribution functions

2017 ◽  
Vol 41 (3) ◽  
pp. 174-184 ◽  
Author(s):  
Mohamed Hatim Ouahabi ◽  
Farid Benabdelouahab ◽  
Abdellatif Khamlichi
Keyword(s):  
Wind Speed ◽  
Measurement Data ◽  
Rayleigh Distribution ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Energy Potential ◽  
Distribution Models ◽  
Wind Speed Data ◽  
Resource Characteristics ◽  
Wind Resource

Several statistical distributions have been considered to model wind speed data. However, Weibull and Rayleigh statistical distributions are the most widely used methods for analyzing wind speed measurements and determining wind energy potential. In this work, these statistical distributions were applied in order to evaluate the wind resources in the northern Moroccan city of Tetouan. Adjustment of wind measurement data was performed. Then, the obtained results were compared with the provided wind data to test their accuracy based on common statistical indicators for performance. It was found that the Weibull and Rayleigh distribution models provide adequate description of the frequencies of actual wind records in Tetouan. They can be advantageously used to assess wind resource characteristics in this region.

scholarly journals Analisis Performance Jangka Pendek Pembangkit Listrik Tenaga Surya dengan Sistem Stand-alone System

2021 ◽  
Vol 8 (1) ◽  
pp. 22-27
Author(s):  
Rhezal Agung Ananto ◽  
Asfari Hariz Santoso
Keyword(s):  
Renewable Energy ◽  
Solar Energy ◽  
Energy Demand ◽  
Measurement Method ◽  
Measurement Data ◽  
Photovoltaic Efficiency ◽  
Variable Voltage ◽  
Measurement Results ◽  
Power Generation Technology ◽  
Power And Energy

Renewable energy power generation technology continues to develop every year and energy demand continues to increase. Reducing carbon emissions in accordance with international carbon emission policies (including Indonesia). The renewable energy target is targeted to increase every year in accordance with the national renewable energy mix policy. Renewable energy has characteristics that fluctuate over time, so continuous measurement data is needed. This data is used for the design of renewable energy in Indonesia in the future. To analyze the performance of a solar power plant, measurement variables are needed. Photovoltaic analysis requires measurement of variable voltage, current, power and energy. Measurement variables are measurement variables from photovoltaic and measurement variables from solar energy. The measurement of solar energy is measured in Watts per square meter. The measurement method is a direct measurement in the territory of Indonesia. The measurement method is the measurement at sunrise to sunset. The measurement results are used for performance analysis. The measurements result are used for photovoltaic efficiency analysis.

scholarly journals Experimental Long-Term Investigation of Model Predictive Heat Pump Control in Residential Buildings with Photovoltaic Power Generation

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6016
Author(s):  
Sebastian Kuboth ◽  
Theresa Weith ◽  
Florian Heberle ◽  
Matthias Welzl ◽  
Dieter Brüggemann
Keyword(s):  
Model Predictive Control ◽  
Heat Pump ◽  
Predictive Control ◽  
Energy Demand ◽  
Residential Buildings ◽  
Global Radiation ◽  
Measurement Data ◽  
Weather Conditions ◽  
Coefficient Of Performance ◽  
Measurement Results

This article presents a 125-day experiment to investigate model predictive heat pump control. The experiment was performed in two parallel operated systems with identical components during the heating season. One of the systems was operated by a standard controller and thus represented a reference to evaluate the model predictive control. Both test rigs were heated by an air-source heat pump which is influenced by real weather conditions. A single-family house model depending on weather measurement data ensured a realistic heat consumption in the test rigs. The adapted model predictive control algorithm aimed to minimize the operational costs of the heat pump. The evaluation of the measurement results showed that the electrical energy demand of the heat pump can be reduced and the coefficient of performance can be increased by applying the model predictive controller. Furthermore, the self-consumption of photovoltaic electricity, which is calculated by means of a photovoltaic model and global radiation measurement data, was more than doubled. Consequently, the energy costs of heat pump operation were reduced by 9.0% in comparison to the reference and assuming German energy prices. The results were further compared to the scientific literature and short-term measurements were performed with the same experimental setup. The dependence of the measurement results on the weather conditions and the weather forecasting quality are shown. It was found that the duration of experiments should be as long as possible for a comprehensive evaluation of the model predictive control potential.

Sign in / Sign up

Export Citation Format

Share Document