LIRA, J. G. A.; http://lattes.cnpq.br/9422522354709015; LIRA, José Gutembergue de Assis.
Résumé:
This work has as an innovative aspect the development of a system capable of
monitoring, storing, analyzing and transmitting - at distance - the information contained in
the leakage current on the state of degradation of the surge arrester. For that we used: a
current sensor in toroidal nucleus, manufactured with nanocrystalline alloy; one innovative
discrimination of the resistive and capacitive components technique and digital signal
processing techniques, as well as a data-communication system, that qualifies it to be used
in the inspection of zinc oxide surge arrester. Its operation aims at to increase the
exactness, the efficiency and the reliability in the monitoring of the surge arresters and,
consequently, the reliability of the electrical system. A new system of acquisition of data is
presented, based on the integration of techniques of analogical and digital signal
processing, so as to study the electric performance of a zinc oxide surge arrester in
operation, from the continuous monitoring of its leakage current. An algorithm of
management and interpretation of the measured data was developed with the possibility of
monitoring continuously, inside of the foreseen intervals of sampling, the occurrence of
changes in the leakage current. The results of the analysis of the leakage current can directly
be transmitted for an operational room through a data communication system.
Additionally, an interface is added to the system to make it compatible and to allow
transmission of the acquired information data registers for automatic diagnosis, by means
of radio frequency, infra-red ray or optic fiber, depending on the configuration of the
installed electric plant. The systems of monitoring, storage, analysis and transmission had
been evaluated individually revealing efficiency and accuracy. The complete system was
evaluated in the dependences of the High-Voltage Laboratory under high intensity of
electric field and the transmission system was capable of sending the signals of the leakage current third harmonic by radio frequency to the reception system.
