Absolute calibration of radiometric partial discharge sensors for insulation condition monitoring in electrical substations

Measurement of partial discharge (PD) is an important tool in the monitoring of insulation integrity in high voltage (HV) equipment. Partial discharge is measured traditionally using galvanic contact techniques based on IEC 60270 standard or near field coupling [1]. Freespace radiometric (FSR) detection of PD is a relatively new technique. This work advances calibration method for FSR measurements and proposer a methodology for FSR measurement of absolute PD intensity. Until now, it has been believed that absolute measurement of partial discharge intensity using radiometric method is not possible. In this thesis it is demonstrated that such measurement is possible and the first ever such absolute measurements are presented. Partial discharge sources have been specially constructed. These included a floating electrode PD emulator, an acrylic cylinder internal PD emulator and an epoxy dielectric internal PD emulator. Radiated signals are captured using a wideband biconical antenna [1]. Free-space radiometric and galvanic contact measurement techniques are compared. Discharge pulse shape and PD characteristics under high voltage DC and AC conditions are obtained. A comparison shows greater similarity between the two measurements than was expected. It is inferred that the dominant mechanism in shaping the spectrum is the band-limiting effect of the radiating structure rather than band limiting by the receiving antenna. The cumulative energies of PD pulses in both time and frequency domains are also considered [2]. The frequency spectrum is obtained by FFT analysis of time-domain pulses. The relative spectral densities in the frequency bands 50 MHz – 290 MHz, 290 MHz – 470 MHz and 470 MHz – 800 MHz are determined. The calibration of the PD sources for used in the development of Wireless Sensor Network (WSN) is presented. A method of estimating absolute PD activity level from a radiometric measurement by relating effective radiated power (ERP) to PD intensity using a PD calibration device is proposed and demonstrated. The PD sources have been simulated using CST Microwave Studio. The simulations are used to establish a relationship between radiated PD signals and PD intensity as defined by apparent charge transfer. To this end, the radiated fields predicted in the simulations are compared with measurements. There is sufficient agreement between simulations and measurements to suggest the simulations could be used to investigate the relationship between PD intensity and the field strength of radiated signals [3]

ANALYSIS OF EVOLUTION AND MORPHOLOGY OF URBAN AND ROAD NETWORKS: CASE STUDY LEBANON-NABATIYEH AREA

This study examines the morphology and evolution of urban and road networks and their relationship with topography in the Lebanon-Nabatiyeh area, by using GIS and remote sensing data. and calculate the annual urban growth percentage rate. The results reveal a clear relationship between the morphology of urban and road networks and their evolution over four periods, as well as the influence of the surrounding topography on their configuration. The study recommends that urban areas should be developed in areas with a slope range of 15º or more to improve the urban structure and infrastructure surrounding them. Understanding the evolution and morphology of urban and road networks is essential for urban planners and policymakers to design efficient and sustainable urban development. Future research should use the method employed in this study and supplement it with the creation of a land suitability map using GIS and remote sensing technology to improve current urban planning protocols. The study provides helpful insights for urban developers, planners, and designers in creating successful approaches to urban development and management

A comparison of fracture strength among different brands of translucent zirconia crown restorations

Objectives: As the development of translucent zirconia crown using CAD/CAM technology, the usage of full zirconia crown is gradually increased. The purpose of this study was to investigate the highest fracture strength of translucent zirconia full zirconia crowns among different brands of translucent zirconia. Methods: Maxillary 1stpremolar resin teeth were prepared the total circumferential axial reduction was about (1 mm), and axial taper of 6°. Three brands of translucent zirconia (Whitepeaks, Imes-icor and Dentaldirect) that was used in three groups, every group contain five full zirconia crowns using CAD/CAM system (CAD/CAM system 250i, Imes-icor, Germany). The samples seated on the resin die using. All specimens were tested with a universal testing machine. Single load-to-fracture was applied on the lingual aspect of the facial cusp at a rate of 1mm/min. The specimens were thoroughly evaluated for bulk fracture with fractography. Results: Statistically high significant difference (p < 0.00) was found between the groups. The fracture strength of the groups varied Whitepeaks crowns was (2737.5 ± 106) N, which was significantly higher than the two overall mean fracture strength measured for the Imes-icor crowns (3620 ± 40) N and Dental direct crowns (3830 ± 130) N, the Dental direct highest fracture strength than other groups. Conclusions. The fracture strength of Dental direct crowns is considerably higher than that of Whitepeaks crown, The fracture strength of all the groups made of monolithic high translucent Y-TZP is exceeded human maximum bite force, sufficient for clinical use for the majority of patients.

Simulation Model of Enhancing Performance of TCP/AQM Networks by Using Matlab

Internet networks are becoming more crowded every day due to the rapid development of modern life, which causes an increase in the demand for data circulating on the Internet. This creates several problems, such as buffer overflow of intermediate routers, and packet loss and time delay in packet delivery. The solution to these problems is to use a TCP/AQM system. The simulation results showed that there were differences in performance between the different controllers used. The proposed methods were simulated along with the required conditions in nonlinear systems to determine the best performance. It was found that the use of optimization Department of Electro-mechanical Engineering, University of Technology - Iraq tools (GA, FL) with a controller could achieve the best performance. The simulation results demonstrated the ability of the proposed methods to control the behavior of the system. The controller systems were simulated using Matlab/Simulink. The simulation results showed that the performance was better with the use of GA-PIDC compared to both FL-PIDC and PIDC in terms of stability time, height, and overrun ratio for a network with a variable queue that was targeted for comparison. The results were: the bypass ratio was 0, 3.3 and 21.8 the settling time was 0.002, 0.055, and 0.135; and the rise time was 0.001, 0.004 and 0.008 for GA-PIDC, FL-PIDC and PIDC, respectively. These results made it possible to compare the three control techniques

Simulation Model of Enhancing Performance of TCP/AQM Networks by Using Matlab

Internet networks are becoming more crowded every day due to the rapid development of modern life, which causes an increase in the demand for data circulating on the Internet. This creates several problems, such as buffer overflow of intermediate routers, and packet loss and time delay in packet delivery. The solution to these problems is to use a TCP/AQM system. The simulation results showed that there were differences in performance between the different controllers used. The proposed methods were simulated along with the required conditions in nonlinear systems to determine the best performance. It was found that the use of optimization Department of Electro-mechanical Engineering, University of Technology - Iraq tools (GA, FL) with a controller could achieve the best performance. The simulation results demonstrated the ability of the proposed methods to control the behavior of the system. The controller systems were simulated using Matlab/Simulink. The simulation results showed that the performance was better with the use of GA-PIDC compared to both FL-PIDC and PIDC in terms of stability time, height, and overrun ratio for a network with a variable queue that was targeted for comparison. The results were: the bypass ratio was 0, 3.3 and 21.8 the settling time was 0.002, 0.055, and 0.135; and the rise time was 0.001, 0.004 and 0.008 for GA-PIDC, FL-PIDC and PIDC, respectively. These results made it possible to compare the three control techniques

Partial discharge source calibration of radiated partial discharge signals

Based on the IEC 60270 guideline, a galvanic quantification along with free-space radiometry (FSR) method are used to measure partial discharge (PD) simultaneously. The PD source is a floating-electrode emulator type that was custom built. Sources are powered by AC or DC, power supplies. A biconical antenna captures the emitted a signal. The frequency band is derived from performing an Time-domain pulsing FFT analytics. The adjustment of a floating-electrode PD supply is focused for the advancement of a PD wireless sensor network (WSN)

Isolation Cellulolytic Fungi from Plants and Animals Wastesin Iraq

134 samples of plants and animals wastes were taken from three different regions outside Baghdad and three different regions in Baghdad. 24 cellulolytic isolates fungi AO, C1, TH1, AN1, R1, TV, PG, AF, B1, L1, AP, TH, AP1, AN3, AO2, A, A1, C, F, AO1, C2, F1, CL and AP2 independent were chosen out of 48 selected fungi. The best optimal conditions for growth were 30ºC and pH 7. The isolates were identified and screened according to the colony diameter, biomass and density of spores in addition of capability to produce the hydrolytic enzymes for cellulose

Effect of different cooling strategies on surface quality and power consumption in finishing end milling of stainless steel 316

In this paper, an experimental investigation into the machinability of AISI 316 alloy during finishing end milling operation under different cooling conditions and with varying process parameters is presented. Three environmental-friendly cooling strategies were utilized, namely, dry, minimal quantity lubrication (MQL) and MQL with nanoparticles (Al$_{2}$O$_{3}$),and the variable process parameters were cutting speed and feed rate. Power consumption and surface quality were utilized as the machining responses to characterize the process performance. Surface quality was examined by evaluating the final surface roughness and surface integrity of the machined surface. The results revealed a reduction in power consumption when MQL and MQL + Al$_{2}$O$_{3}$ strategies were applied compared to the dry case by averages of 4.7% and 8.6%, respectively. Besides, a considerable reduction in the surface roughness was noticed with average values of 40% and 44% for MQL and MQL + Al$_{2}$O$_{3}$ strategies, respectively, when compared to the dry condition. At the same time, the reduction in generated surface roughness obtained by using MQL + Al$_{2}$O$_{3}$condition was marginal (5.9%) compared with using MQL condition. Moreover, the results showed that the improvement obtained in the surface quality when using MQL and MQL + Al$_{2}$O$_{3}$ coolants increased at higher cutting speed and feed rate, and thus, higher productivity can be achieved without deteriorating final surface quality, compared to dry conditions. From scanning electron microscope (SEM) analysis, debris, furrows, plastic deformation irregular friction marks, and bores were found in the surface texture when machining under dry conditions. A slight smoother surface with a nano-polishing effect was found in the case of MQL + Al$_{2}$O$_{3}$ compared to the MQL and dry cooling strategies. This proves the effectiveness of lubricant with nanoparticles in reducing the friction and thermal damages on the machined surface as the friction marks were still observed when machining with MQL comparable with the case of MQL + Al$_{2}$O$_{3}$

Radiometric Wireless Sensor Network Monitoring of Partial Discharge Sources in Electrical Substations

A wireless sensor network (WSN) with the potential to monitor and locate partial discharge (PD) in high-voltage electricity substations using only received signal strength (RSS) is proposed. The advantages of an RSS-based operating principle over more traditional methods (e.g., time-of-arrival and time-difference-of-arrival) are described. Laboratory measurements of PD that emulate the operation of a PD WSN are presented. The hardware architecture of a prototype PD WSN is described and the particular challenges of an RSS-based location approach in an environment with an unknown, and spatially varying, path-loss index are discussed. It is concluded that an RSS-based PD WSN is a plausible solution for the monitoring of insulation integrity in electricity substations

Calibration of Free-Space Radiometric Partial Discharge Measurements

The present study addresses the calibration of four types of partial discharge (PD) emulators used in the development of a PD Wireless Sensor Network (WSN). Three PD emulators have been constructed: a floating-electrode emulator, and two internal PD emulators. Both DC and AC high-voltage power supplies are used to initiate PD, which is measured using concurrent free-space radiometry (FSR) and a galvanic contact method based on the IEC 60270 standard. The emulators have been measured and simulated, and a good agreement has been found for the radiated fields. A new method of estimating the absolute PD activity level from radiometric measurements is proposed