| 摘要 |
<p>In a short-circuit distance relay for protecting a single-channel power transmission system with power supplies installed at two ends thereof, when there exists any resistance at a fault point on the power transmission line, an error is induced in measurement of the distance up to the fault point by a voltage drop component flowing through the fault-point resistance from the remote-end power supply. In order to eliminate such error in measuring the distance, the relay of this invention computes the impedance up to the fault point from the information including a positive-phase voltage and a positive-phase current in a normal state of the power transmission system, and also a positive-phase voltage, a positive-phase current and a negative-phase current in a faulty state of the system, whereby the fault-point resistance is rendered unconcerned with the distance to consequently avert the measurement error.</p> |
