Sistema de medição de picos de corrente de fuga para isoladores de alta tensão

Abstract

The proper application of measurement instruments and techniques is essential to ensure the correct operation and safety of systems used in various practical applications in society, such as in the provision of electrical power. A physical phenomenon that can affect these systems, resulting in spikes in the electrical network signals, is partial discharge. Evidence indicates a direct relationship between the occurrence of partial discharges, regardless of their source, the degradation of high-voltage insulators’ performance, and the manifestation of spikes in the measured leakage current on the insulator. However, the acquisition and processing of this information are complex due to various factors, resulting in gaps in the literature. The complexity is further exacerbated by the lack of attention to fundamental aspects of instrumentation, such as the evaluation of the suitability of the measurement system components for the application. In this context, this study aims to develop, characterize, and evaluate a measurement system for detecting leakage current spikes in high-voltage insulators, regardless of the reason for their occurrence, as well as to scientifically investigate aspects related to the measurement of the quantity of interest. An inductive sensor was developed to monitor the current spikes in the signal of interest, which was artificially generated to allow the investigation of the measurement system’s characteristics in challenging situations. Results from the characterization and uniformity experiments of the sensor led to conclusions about the experimental setup, the shape and equation of the measurement curve, the technical specifications of the system, and its ability to handle both disturbances in the electrical network and low-frequency components in the leakage current signal and the timing of the spike occurrence - all aspects commonly overlooked in the literature.