This paper presents a methodology capable of measuring, processing, and extracting contact resistance parameters that enable the identification of the contact degradation level inside arc extinction chambers in medium- and high-voltage circuit breakers (CB). To determine the contact degradation level, an algorithm was developed to extract the characteristic parameters from the results of dynamic resistance measurement (DRM). To analyze the dataset parameters, this work employs the combination of different statistical tools, such as boxplots and fuzzy logic, enabling the evaluation to be conducted without the subjectivity inherent in human decision. Therefore, a more objective and reliable diagnosis could be achieved. The DRM tests were performed on two types of minimum-oil CB (MOCB), 800 A/15 kV/12.5 kA (CB-A) and 2000 A/72.5 kV/31.5 kA (CB-B and CB-C). For CB-A and CB-B, three contacts were utilized for each CB, with significant contact degradation. For CB-C, a single contact was employed without significant degradation. The DRM curves of the CB-C contact were used as the reference for evaluation of the CB-B contacts. For this purpose, a new DRM system was developed. The proposed methodology can be defined as a complement for other diagnostic techniques, serving as a non-subjective asset management tool, supporting decisions regarding equipment interventions.

Surge arresters are part of the protection system of electrical substations and transmission and distribution networks. They avoid damages in equipments of main importance for the electric system, such as power transformers, not allowing them to be reached by overvoltages. An arrester presenting any kind of failure may not actuate in a satisfactory way during the occurrence of an electric surge. As a consequence, it will present an overheating which can lead to its complete degradation and exposing the system that should be protected and bringing risk to those who are working nearby [1]. In order to avoid this kind of problem, several monitoring techniques are used. The measurement of leakage current and the thermal analysis are the most used of these techniques. A work being developed in the High Voltage Laboratory of the Universidade Federal de Campina Grande together with the Companhia Hidrelétrica do São Francisco has the main purpose of developing a technique to be used for arrester monitoring by means of continuous analysis of its leakage current and variations on its thermal patterns, resulting in a useful tool for the diagnosis and preview of failures in ZnO arresters.

Lightning strikes are a leading cause of outages on overhead transmission lines, significantly compromising power system reliability. Consequently, monitoring lightning activity is critical to mitigate its impact on lines with high outage rates. This study presents an autonomous lightning strike counter system utilizing a split-core Rogowski coil for non-invasive current measurement on transmission towers. The system combines the Rogowski coil with an active integrator circuit to reconstruct the incident current waveform from the coil voltage signal. A microcontroller-based processing unit records strike occurrences and classifies them by amplitude using predefined thresholds. Laboratory tests were carried out to evaluate the performance of the Rogowski coil and integrator circuit, validating the system accuracy in detecting current pulses associated with lightning strikes. Underway field tests will assess the sensor’s reliability during long-term autonomous operation on 345-kV transmission towers. The results demonstrate that the proposed system represents a practical and cost-effective solution for lightning monitoring in remote areas, contributing to enhanced data collection for engineering studies and improved reliability of electrical infrastructure.

This paper aimed at the design and development of a data acquisition and control system using the Arduino open-source platform to automate equipment responsible for the IEC 60587 electrical tracking and erosion test. The developed system allows the selection of protection resistors specified by the standard from the voltage value informed by the operator, monitoring of the leakage current flowing over five samples simultaneously tested and automatically interrupts the samples if the leakage current exceeds 60 mA for more than two seconds. The leakage current values are measured indirectly from the voltage drop across 50 Ω shunt resistors installed in series with each sample. The voltage values on the shunt resistors are conditioned by a measuring circuit that allows the voltage level to be adjusted to the analog inputs of the microcontroller, ie, between 0 V and 5 V. The microcontroller treatment performs the voltage signal obtained by the measuring circuit, the calculation of the RMS value of the current and stop criterion monitoring the leakage current. The calibration of the leakage current measurement circuit was performed by comparing voltage values measured by a digital oscilloscope for four different alternate waveforms and values up to 5 Vrms, corresponding to currents up to 100 mA. The results showed that the circuit provided measurements close to the values measured by the oscilloscope, with errors below 11%. For current values between 30 mA and 80 mA, the errors were less than 6%.

A aplicação de materiais poliméricos no desenvolvimento de produtos e no revestimento de equipamentos destinados a aplicações de uso externo tem aumentado significativamente com os avanços tecnológicos e na ciência dos materiais. No entanto, os polímeros são susceptíveis a degradação provocada pela ação dos diversos agentes presentes no meio ambiente e que podem ocasionar falhas prematuras em serviço. A realização de testes de envelhecimento acelerado em laboratório permite avaliar o comportamento dos materiais poliméricos em curtos períodos e detectar materiais com propriedades inadequadas ou susceptíveis a falhas. Um dos testes consiste na utilização de câmaras de envelhecimento acelerado que permitem submeter amostras do material polimérico à radiação ultravioleta, temperatura e umidade. No entanto, os equipamentos disponibilizados no mercado possuem valores elevados e que dificultam a aquisição pelos laboratórios de pesquisa. Neste contexto, o presente trabalho teve como objetivo o projeto e desenvolvimento de uma câmara de envelhecimento acelerado de baixo custo para a realização de ensaios com materiais poliméricos. O equipamento é constituído por lâmpadas ultravioleta e um sistema de condensação que permitem simular a exposição de amostras à radiação UV, temperatura e umidade. Os mecanismos podem ser selecionados e operados de forma cíclica a partir de um sistema de controle microcontrolado baseado na plataforma open-source Arduino.