An electro-opto-electronic system for the directional detection of earth faults and of short-circuit faults in medium-voltage electrical networks

摘要

An electro-opto-electronic system for the directional detection of earth faults in phase conductors (CFR, CFS, CFT) and of short-circuit faults between the conductors (CFR, CFS, CFT) in medium-voltage electrical network lines, comprises:
<UnorderedLists id="ula01" listStyle="none"><ListItem>capacitive shunts (DCR, DCS, DCT) connected to the conductors (CFR, CFS, CFT) and respective first electro-optical convertors (EOVR, EOVS, EOVT) for generating first light signals representative of the presence of voltage (Er, Es, Et) between each conductor and earth and second light signals representative of the phase angle of the voltages (Er, Es, Et),</ListItem><ListItem>amperometric current transformers (TAIO, TAIR, TAIT) connected to the conductors (CFR, CFS, CFT) and respective second electro-optical converters (EOIO, EOIR, EOIT, EOITd) for generating third light signals representative of the phase angle of the homopolar current (I<Sub>0</Sub>) of the line,</ListItem><ListItem>optical conductors (FO) for the remote transmission of the light signals, and</ListItem><ListItem>an electronic control unit (UE) arranged to determine the occurrence of a fault and/or the presence of voltage on the line, in dependence on the phase relationships between the signals received, which are representative of the voltages (Er, Es, Et) between each conductor and earth, on the homopolar voltage (E<Sub>0</Sub>), and on the homopolar current (I<Sub>o</Sub>).</ListItem></UnorderedLists>

The system determines the phase angle of the homopolar voltage (E0) of the line by analog or digital means, in dependence on the phase relationships between the signals representative of the voltages (Er, Es, Et) present between each conductor and earth.