| Patent application number | Description | Published |
|---|
| 20090021878 | METHOD AND ADAPTIVE DISTANCE PROTECTION RELAY FOR POWER TRANSMISSION LINES - A method and an adaptive distance protection relay for compensating for a remote line end infeed effect during determination of a distance to a resistive fault on a three-phase power transmission line. It is assumed that a fault current flows through the fault resistance. A fault loop impedance is first calculated by a known algorithm from phase voltages and phase currents. A shift of the fault loop impedance is determined from the fault loop impedance, the impedance of the transmission line for the positive current sequence and the phase angle of a complex fault current distribution factor, where the fault current distribution factor is the ratio of the fault loop current to the fault current. The distance to fault is calculated by subtracting the impedance shift from the fault loop impedance and dividing the result by the impedance of the transmission line for the positive current sequence. | 01-22-2009 |
| 20090150099 | Method for fault location in electric power lines - A method for locating faults in three-terminal and multi-terminal power lines, applicable in electric power systems for overhead and underground cable transmission and distribution lines. The inventive method is characterised in that it measures current for fault and pre-fault conditions and in one terminal station of the system line phase voltage for fault and pre-fault conditions is measured, a hypothetical fault location is assumed, the distances to the hypothetical fault locations are calculated and fault resistance is calculated, the actual fault point is selected by first comparing the numerical values concerning the distances to the hypothetical fault locations and rejecting those results whose numerical values are negative or bigger than one in relative units, and then by analysing the values of the calculated fault resistances for the fault locations and rejecting those results of the calculations for which the value of fault resistance is negative, and if there is still more than one calculation result remains not rejected then performing selection of the valid result by analysing the values of the calculated respective equivalent source impedances. | 06-11-2009 |
| 20100277181 | METHOD AND DEVICE FOR FAULT LOCATION IN A TWO-TERMINAL TRANSMISSION OR DISTRIBUTION POWER LINE - A method for locating a fault in a two-terminal power transmission or distribution line. Measurements of the three phase currents are received from both terminals. Measurements of the three phase voltages are received from one line terminal. Parameters of the line are received. The fault type is received. Based on this received information the distance to fault from the one terminal where the phase voltages were measured is determined and output. Since only the phase voltages of one line terminal are needed, the functionality of a device, in particular a current differential relay, can be expanded to determine the distance to fault in an off-line mode. | 11-04-2010 |
| 20110037480 | METHOD FOR FAULT LOCATION IN UNCOMPENSATED POWER LINES WITH TWO-END UNSYNCHRONIZED MEASUREMENT - A method is provided for fault location in uncompensated power lines with two-end unsynchronized measurement, finding an application in the power industry and for overhead and overhead-cable transmission or distribution lines. The method according to the invention includes measuring the voltage and currents at both ends (A) and (B) of the section, obtaining the phasor of the positive sequence voltages (V | 02-17-2011 |
