Concepção e desenvolvimento de um medidor de impedância impulsiva de aterramentos de linhas de transmissão

Abstract

This Ph.D dissertation presents a new grounding impedance measuring system, based on DSP (Digital Signal Processor) platform. The low-cost portable device includes a built-in voltage impulse generator, non-volatile memory for storage of measured current and voltage waves and a graphical display for fast data visualization and user interface. The device includes an integrated controller that is able to process the calculations required to yield complete results, even in absence of PC laptop support. Though the primary application is focused on the measurement of transmission line tower-footing impedance, it can be extended to the measurement of any electrode arrangement. In this text, general hardware structure overview and software implementation are presented. Consistent preliminary field-test results were provided by the measuring system, consisting of records of grounding potential rise and impressed current, impulse impedance and estimated low-frequency grounding resistance obtained for different electrode arrangements buried in low and high resistivity soils. The results demonstrate that this portable low-cost, low-weight, stand-alone impedance measuring system based on DSP processor consists of an effective tool for assessing the lightning response of grounding electrodes and can be very useful in lightning protection applications.