| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground fault distance protective relay device of a practical structure which determines a polarity quantity from an inter-line difference current between parallel transmission lines to solve problems that arise when a feather quantity is used in carrying out distance-measuring calculation. SOLUTION: The ground fault distance protective relay includes a means which detects the currents and voltages of transmission lines, a converting means which converts an analog output from the detecting means into a digital output, a means which converts an output from the converting means into a feather quantity, a means which derives a difference current from the current in terms of feather quantity of one line and a current in terms of feather quantity of the adjacent line, a polarity quantity calculating means which subjects the difference current to a phase shift process to obtain a signal and outputs the obtained signal in terms of polarity quantity, and a calculating means which calculates a distance up to a ground fault accident point from the output polarity quantity from the polarity quantity calculating means and the voltage in terms of feather quantity of the one line to identify the ground fault accident. The ground fault distance protective relay is practically useful when a polarity quantity is determined from an inter-line difference current between parallel transmission lines to use a feather quantity in carrying out distance-measuring calculation. COPYRIGHT: (C)2011,JPO&INPIT
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