Abstract: A method to locate a fault from one end of a section of a power line utilizing measurements of current, voltage and angles between the phases at a first end of said section. Symmetrical components of currents are calculated for the current and voltage measurement at the first end. A value of impedance is calculated for an extra link between the terminals with the impedance for the positive sequence. A compensation is determined for the shunt capacitance. The zero-sequence current is determined from the healthy line of a section of parallel power lines. A distance to a fault is calculated for the parallel line section. The distance to the fault from the first end is calculated. The fault is located utilizing the calculate distances.

Abstract: A method for locating a fault in three terminal power line, having sections located in front of or behind of the tap point and which assumes occurrence of the fault in at least one of those sections. Three phase currents and voltages are measured at one end of the power lines system. The amplitudes of load currents in the remaining sections of the power lines system are measured before a fault occurs. The measurements of the amplitudes of load currents are stored in the remaining sections of the power lines system. Impedance data of the network are determined. The symmetrical components approach is used when calculating the location of the fault.

Abstract: The present invention relates to a method to locate a fault in a section of a transmission line using measurements of current, voltage and angles between the phases at a first (A) and a second (B) end of said section. The invention is characterised by the steps of, after the occurrence of a fault along the section, calculating a distance (dA, dB) to a fault dependent on a fault current measured at one of said first and second ends and phase voltages measured at both of said first and second ends (A, B), where the distance to fault is calculated from the end (A or B) where the fault current is measured. The invention is particularly suitable when a current transformer at either of the first or second ends (A, B) is saturated. If so, then, a distance (d) to a fault is calculated dependent on a fault current measured at the non-affected end and phase voltages measured at both the affected end and the non-affected end.

Abstract: The present invention relates to a method for locating a fault (F) in a section of parallel transmission lines in a network comprising the steps: measuring the currents and voltages of both lines at a measuring point arranged at one end (A) of the section, determining the fault distance (x) between the measuring point and the fault as a solution of an equation Ax2−Bx+C−Rf=0 comprising the fault distance (x) as a variable and the fault resistance (Rf), the invention is characterised in that the parameters (A, B, C, D) comprise the phase components of the locally measured currents and voltages and are obtained from calculating from the measuring point to the fault location along the both parallel lines, and wherein the equation is resolved into its real and imaginary parts: Real(A)x2−Real(B)x+Real(C)−Rf=0 Imag(A)x2−Imag(B)x+Imag(C)=0, whereby the fault distance is derived from the imaginary part.

Abstract: The present invention relates to a method for locating a fault (F) in a section of parallel transmission lines in a network comprising the steps: measuring the currents and voltages of both lines at a measuring point arranged at one end (A) of the section, determining the fault distance (x) between the measuring point and the fault as a solution of an equation Ax2−Bx+C−Rf=0 comprising the fault distance (x) as a variable and the fault resistance (Rf), the invention is characterizsed in that the parameters (A, B, C, D) comprise the phase components of the locally measured currents and voltages and are obtained from calculating from the measuring point to the fault location along the both parallel lines, and wherein the equation is resolved into its real and imaginary parts:

Abstract: The present invention relates to a method for locating a fault (F) in a section of parallel transmission lines in a network comprising the steps: measuring the currents and voltages of both lines at a measuring point arranged at one end (A) of the section, determining the fault distance (x) between the measuring point and the fault as a solution of an equation Ax2−Bx+C−Rf=0 comprising the fault distance (x) as a variable and the fault resistance (RF), the invention is characterized in that the parameters (A, B, C, D) comprise the phase components of the locally measured currents and voltages and are obtained from calculating from the measuring point to the fault location along the both parallel lines, and wherein the equation is resolved into its real and imaginary parts:

Abstract: A method and a device for identifying, when a fault has been detected in a power network, single-phase to ground faults by determining for each phase an auxiliary current based on the present phase current, ground fault current and ground current. If the difference between two consecutive, calculated values of the auxiliary current in some phase is smaller than a predetermined limit value, this means that there is a single ground fault in this phase.