Search results for "Discharge"

Simplified Hybrid PD Model in Voids

2011

In this paper a novel approach to model partial discharges (PD) activity taking place inside a spherical void in epoxy resin system has been traced. The approach is based on a time varying conductance of the inner void, subjected to multistress conditions: voltage, temperature and pressure. A simple lumped circuit macro-model simulates the global effects of PD activity: the different parameters influencing the discharge phenomenon in the void are taking into account by using a physical approach resulting in a time varying conductance inside the circuit. The evaluated PD activity has been compared with experimental and simulated one for the accessible and inaccessible part of the system. A d…

Simplified hybrid PD model in voids: Pattern validation

2013

The purpose of the present work is to show the validation of a new model to simulate the physical phenomenon of partial discharge (PD) produced in air voids inside insulating epoxy resin. The model has been developed on the basis of a new approach that combines the known circuit model of three capacitors with a model used to describe the behavior of the ionized channel inside of the inclusion during the discharge phenomenon, short-circuiting the capacity that represents the void. The approach is based on time-variable conductance of the void, subjected to multistress conditions: voltage, temperature and pressure. The new approach has been developed from a time variable conductivity model us…

A Novel Histogram for Partial Discharge Signals in HV Insulating Systems

1986

A technique for relating measurable electrical quantities with energies dissipated inside a void in highly electrically stressed insulation is presented. It is based on measuring, for each apparent discharge level qe, the algebraic sum of the external energy pulses of all discharges having a value qe and occurring over some cycles of test voltage. Theoretical investigations show that the results of such external energy summations are equal to the energies dissipated in the void. A novel histogram is also suggested which relates the apparent discharge amplitudes with their respective energies in the void. Experimental tests were carried out under controlled conditions with samples of thermop…

International Legal Approaches to Waste Water Discharges. Opening speech

2002

En este discurso inaugural, realizo una introducción a la frustrante situación jurídica en la que se encuentran las descargas de aguas residuales a nivel internacional. Las descargas de aguas residuales son la mayor fuente de contaminación marina y, en consecuencia, ellas representan el mayor riesgo actual para la protección del medio ambiente marino. In this opening speech, I make an introduction to the disappointing legal situation of waste water discharges at international level. Waste water discharges is the main source of marine pollution and, therefore, they represent the major current risk to the protection of the marine environment.

New-stage discharge relationship for weirs of finite crest lenght

2014

AbstractThe flow process of weirs of finite crest length is analyzed on the basis of the dimensional analysis and incomplete self-similarity theory. The crest length is incorporated in the functional stage-discharge relationship for weirs of finite crest length. The theoretically deduced stage-discharge formula was then calibrated using the experimental data compiled in this research. According to the current experimental data it is also concluded that the performance of the proposed stage-discharge formula is better than the previous dimensional stage-discharge formulae. Also, the proposed stage-discharge formula is applicable for all types of the weirs, i.e., long-crested, broad-crested, …

Closure to “Theoretical End‐Depth‐Discharge Relationship for Free Overfall” by Vito Ferro

2000

Influence of Site and Check Dam Characteristics on Sediment Retention and Structure Conservation in a Mexican River

2020

Previously, in a large river of Mexico regulated by more than 200 check dams, we demonstrated that vegetation cover and channel characteristics were the dominant factors on the structure conditions and capacity to store sediments. This study focuses on other categorical (i.e., check dam type and location, soil texture and land use) and numerical (i.e. water discharge, check dam dimensions) variables, to whom statistical analysis is applied, in order to assess their influence on sediment filling degree and conditions (functional or destroyed) of the check dams in the same river. ANOVA has shown that: (i) check dam type (gabion or stone) and location (headwater, middle or valley reaches), and…

Climate change impact on SWAT simulated streamflow in western Kenya

2008

Weather and climate extremes such as droughts and floods have far reaching impacts in Kenya. They have had implications in a variety of sectors including agriculture, water resources, health, energy, and disaster management among others. Lake Victoria and its catchment support millions of people and any impact on its ability to support the livelihoods of the communities in this region is of major concern. Thus, the main objective of this study was to assess the potential future climatic changes on the Nzoia catchment in the Lake Victoria basin, and how they might affect streamflow. The Soil and Water Assessment Tool was used to investigate the impact of climatic change on streamflow of the …

Seasonal and Inter-annual Variation of Evapotranspiration in Amazonia Based on Precipitation, River Discharge and Gravity Anomaly Data

2019

We analyzed seasonal and spatial variations of evapotranspiration (ET) for five Amazon sub-basins and their response to the 2015/16 El Nino episode using a recently developed water-budget approach. ET varied typically between similar to 7 and 10 cm/month with exception of the Xingu basin for which it varied between 10 and 15 cm/month. Outstanding features of ET seasonality are (i) generally weak seasonality, (ii) two ET peaks for the two very wet catchments Solimoes and Negro, with one occurring during the wet season and one during the drier season, and (iii) a steady increase of ET during the second half of the dry season for the three drier catchments (Madeira, Tapajos, Xingu). Peak ET oc…

Partial discharge tests using CIGRE method II

2000

In this paper, the results of an experimental project on insulating material aging, performed in both Denmark and Italy, are reported. This study was concerned with partial discharge (PD) behavior at temperatures between 30 and 80/spl deg/C using CIGRE method II. The material tested was a commercial polymethylmethacrylate (PMMA) which was chosen not for its good dielectric properties but rather because much of its discharge resistance data at ambient temperature is already well documented. A description is given of the theoretical and experimental methodology followed in this work. Mixed Weibull analysis techniques in terms of the PD amplitude and phase distribution characteristics were emp…