J. M. R. de Souza Neto

Propagation measurements and modeling for monitoring and tracking in animal husbandry applications

Transmission loss measurements using IEEE 802.15.4 technology are reported in an outdoor environment for application to monitoring and tracking of small ruminants. The simplest possible propagation model is shown to reflect the general features of the measured propagation data. Its absolute accuracy, however, is probably inadequate for use in a location algorithm based on model inversion without optimization of its parameters. Model calibration to reflect inter-site variation of the propagation environment is suggested as a possible way of realizing a location system with useful accuracy and adequate portability.

Partial Discharge Location using Unsynchronized Radiometer Network for Condition Monitoring in HV Substations - A Proposed Approach

A location estimation system for online Partial Discharge (PD) detection is proposed as a low-cost approach to real-time condition monitoring, asset management and operation optimization in future smart grid. Some early progress in the development of subsystems (specifically the antenna, radiometer device, PD emulator and PD generator) for a proof-of-principle prototype system is described. The proposed PD Wireless Sensor Network (WSN) uses a novel approach to PD location which obviates the need for synchronization between sensors thereby improving scalability.

Wavelet transform processing applied to partial discharge evaluation

Partial Discharge (PD) is characterized by high frequency current pulses that occur in high voltage (HV) electrical equipments originated from gas ionization process when damaged insulation is submitted to high values of electric field [1]. PD monitoring is a useful method of assessing the aging degree of the insulation, manufacturing defects or chemical/mechanical damage. Many sources of noise (e.g. radio transmissions, commutator noise from rotating machines, power electronics switching circuits, corona discharge, etc.) can directly affect the PD estimation. Among the many mathematical techniques that can be applied to de-noise PD signals, the wavelet transform is one of the most powerful. It can simultaneously supply information about the pulse occurrence, time and pulse spectrum, and also de-noise in-field measured PD signals. In this paper is described the application of wavelet transform in the suppression of the main types of noise that can affect the observation and analysis of PD signals in high voltage apparatus. In addition, is presented a study that indicates the appropriated mother-wavelet for this application based on the cross-correlation factor.

Development of a partial discharge emulator for calibration of a radiometric PD detection system

A purely electronic partial discharge emulator for use in a location estimation algorithm for online partial discharge detection is proposed as a low-cost approach to real-time condition monitoring, asset management and operation optimization in future smart grid. Some early progress in the development of subsystems (specifically the radiometer antenna and PD emulator) for a proof-of-principle prototype system are described.

Early progress in the development of a radiometric PD location system

A low-cost, free-standing, radiometric, partial discharge wireless sensor network (PD WSN) is described for application to real-time condition monitoring, asset management and operations optimization in the future smart grid. The proposed PD WSN uses a novel approach to PD location which obviates the need for synchronization between sensors thereby improving scalability. Progress in the development of several components for a prototype PD WSN is described.

A self-calibrating partial discharge WSN for condition monitoring in the future smart grid

A self-calibrating wireless sensor network (WSN) of radiometers designed to detect PD radiation is proposed as a low-cost approach to real-time condition monitoring, asset management and operational optimization in the future smart grid. The principles of the proposed PD WSN are described in detail. Some early progress in the development of subsystems for a proof-of-principle prototype is also presented.

Plausibility of incoherent detection for radiometric monitoring of insulation integrity in HV substations

The work reported here is part of a PhD research relates to the development of a new type of radiometric system applied to detection of partial discharges signals. A simulation model for the radiometric transmission of a partial discharge pulse is presented. The model is based on a replay model, which acts as a source, which is based on real data to simulate the pulses. The structure considers losses due to the free space transmission path and interferences caused by carriers from broadcast transmissions. A receiver, focus of this research, is based on a radiometer structure, which includes an amplifier, a filter and an envelope detector to minimize the necessity of a high sample rate ADC.

An Envelope Detector as a Trading Cost Technique for Radiometric Partial Discharge Detection

Partial discharge (PD) measurement is an established high voltage insulation monitoring technique used to facilitate the detection of incipient faults in high voltage apparatus. Based on the great importance of the power system, is constant the research about the nature and characteristics of PD sources. A low-cost, free-standing, radiometric, partial discharge wireless sensor network (PD WSN) is described for application to real-time condition monitoring, asset management and operations optimization in the future smart grid. The proposed PD WSN is based on a novel approach to PD location which obviates the need for synchronization between sensors thereby improving scalability. In this paper, the progress in the development of a PD WSN prototype is described. For the proposed evaluation of PD signals, several measurements were performed using a diskcone antenna and a commercial system based on the IEC 60270 standard. Early progress in the development of components for a PD detection system using a network of free-standing radiometers for monitoring of electricity substations has been also presented.

Design of an experimental methodology for generation of partial discharges signals

Partial discharges measurements are an important tool for the determination of the degradation level of high voltage apparatus. If partial discharge is found in insulating systems then it is important to identify its character, i.e. internal discharge, surface discharge, corona etc. The aim of this paper is present a methodology for the generation of partial signals with different characteristics using two developed partial discharge cell, that allows the generation of well defined PD pulses, that can be used in creation of patterns that allow the automatic (aid computer) defects classification based on the employment of artificial intelligence techniques.

The influence of void configuration in statistical parameters of partial discharge signals

Partial discharge measurement has long been used to evaluate insulation system design and as a quality assurance test for High Voltage (HV) apparatus prior to installation. PD is characterized by high frequency current pulses originating in gas ionization processes when damaged insulation is submitted to high values of electric field. PD process modeling allows a better understanding of the phenomena. The characterization of PD resulting from a single void in an insulation sample has been widely reported. The study of PD originating from multiple voids is, however, less common. In this paper, an evaluation of ten void configurations is reported. Well-defined insulation defect configurations were defined and the electric field of each configuration was simulated using finite elements method. Each configuration was reproduced using a physical PD generator developed for this and similar studies. The emulated PD was recorded using a classical PD measurement system. Statistical parameters have been calculated for each configuration.