METHOD FOR DETERMINING THE SHORT CIRCUIT LOCATION ON TPL WITH A BRANCH Russian patent published in 2023 - IPC G01R31/08 

FIELD: electrical engineering.

SUBSTANCE: relay protection and automation, used to determine the location of a short circuit to ground on a power transmission line (PTL). The distance to the short circuit location is estimated as the length of the path, during the passage of which the wave of the earth wave channel lags behind the wave of the interphase wave channel by a time equal to the value of the time interval between the moments of arrival from the short circuit location to the installation site of the device of the primary waves of these wave channels. In this case, the value of the mentioned time period is linearly converted by a time counter into a unipolar signal. To do this, the time counter is started at the moment the amplitude discriminator of the interphase wave channel is triggered and stopped at the moment the amplitude discriminator of the earth wave channel is triggered. Moreover, the amplitude discriminator of the earth wave channel is put into operation only when the amplitude discriminator of the interphase wave channel is triggered, and the time counter is reset to zero when its reading reaches the specified value. A TPL section with a short circuit is determined by monitoring a unipolar signal with a comparator with two thresholds, the levels of which are proportional to the time counter readings in case of a short circuit to ground at the beginning and end of the branch. In this case, the TPL sections forming the path that the waves travel from the short circuit location to the installation site of the device are determined according to the short circuit location on TPL. The short circuit location can be determined by assessing two devices installed at the TPL ends. To do this, each device exchanges estimates of the distance to the short circuit location with another device via data channels. The short circuit location is considered to be on the segment between two assessments relating either to one of the TPL sections or to a branch.

EFFECT: increasing the accuracy of estimating the distance to the short circuit location on a main PTL with a branch.

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