Abstract: The present invention is concerned with a method of distance protection of parallel transmission lines applicable both to series compensated and uncompensated electric power lines, using a distance relay. The method is characterized in that a pair of flags (ff1, ff2) are calculated for indication faulted and healthy circuits in parallel lines and in the same time a flag (Internal_Fault) for indication internal or external fault in parallel lines is calculated independently. Next gathering all calculated flags (ff1, ff2, Internal_Fault) an analyze of the value of these flags are performed and depending on the values of flags (ff1, ff2, Internal_Fault) and on their reciprocal relationship, a trip permission signal from the protection relay (4) is released and sent to the alarms devices or to the line breakers, or a block signal from the protection relay (4) is generated and sent to protect parallel lines before damage.

Abstract: A transmission line system, a device for fault protection and computer programs, and a method for locating a fault in a series-compensated two-terminal power transmission line including a compensating bank for providing series-compensation to the transmission line. Different subroutines are utilized for locating faults on line segments from the first terminal to the compensating bank and line segments from the second terminal to the compensating bank. A selection is then made in order to determine a valid result. The subroutines utilize three phase currents synchronized measurements from both terminals and a three phase voltage measurements from one terminal for determining the respective per unit distance to a fault.

Abstract: The present invention is concerned with a method for faulted phase selection and fault type determination in electric power lines applicable both to series compensated and uncompensated power lines. The method comprising a fault inception detection and an estimation of fault phase current signals, pre-fault current signals and zero-sequence current in order to receive the absolute value of incremental current signals and their maximum value from which real value indicators for phase to phase faults, real value indicators for 3-phase fault and a real value indicator for ground fault are determined. The method further comprises calculating the maximum of the value of all fault type indicators (Fflt), determining the fault type, which determines the fault type on the basis that the index (flt) means the specific type of fault indicated by the value of flt; and presenting the real fault type indicator (Fmax).

Abstract: The present invention is concerned with a method of distance protection of parallel transmission lines applicable both to series compensated and uncompensated electric power lines, using a distance relay. The method is characterized in that a pair of flags (ff1, ff2) are calculated for indication faulted and healthy circuits in parallel lines and in the same time a flag (Internal_Fault) for indication internal or external fault in parallel lines is calculated independently. Next gathering all calculated flags (ff1, ff2, Internal_Fault) an analyze of the value of these flags are performed and depending on the values of flags (ff1, ff2, Internal_Fault) and on their reciprocal relationship, a trip permission signal from the protection relay (4) is released and sent to the alarms devices or to the line breakers, or a block signal from the protection relay (4) is generated and sent to protect parallel lines before damage.

Abstract: A method for fault location in series compensated power transmission lines using two-end unsynchronized voltage and current measurements in stations A and B. The method includes performing a subroutine I for determining whether the fault occurred in a line section LA between the station A and a SC&MOV and the distance dA to the fault from station A. Subroutine II determines whether the fault occurred in a line section LB between the station B and the SC&MOV and the distance dB to the fault from station B. The synchronization angle ej?A is determined in subroutine I, and the synchronization angle ej?B is determined in subroutine II. Then, the distance to fault dA or dB is determined. Finally, an equivalent impedance of compensating banks at fault stage ZSC1—phSUB—A and ZSC1—phSUB—B, and pre-fault stage ZSC1—pre is calculated in order to determine whether distance dA or dB is the final result.

Abstract: 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 (VA1, VB1) measured at the ends (A) and (B), respectively, obtaining the phasor of the positive sequence currents (IA1, IB1) measured at the ends (A) and (B), respectively, determining whether there is a three-phase balanced fault, and using either a first subroutine or a second subroutine (depending on whether or not there is a fault), determining a distance (d) to the fault.

Abstract: The present invention is concerned with a method for faulted phase selection and fault type determination in electric power lines applicable both to series compensated and uncompensated power lines. The method comprising a fault inception detection and an estimation of fault phase current signals, pre-fault current signals and zero-sequence current in order to receive the absolute value of incremental current signals and their maximum value from which real value indicators for phase to phase faults real value indicators for 3-phase fault and a real value indicator for ground fault are determined. The method further comprises calculating the maximum of the value of all fault type indicators (Fflt) determining the fault type, which determines the fault type on the basis that the index (flt) means the specific type of fault indicated by the value of flt; and presenting the real fault type indicator (Fmax).

Abstract: 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.

Abstract: 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.

Abstract: A transmission line system, a device for fault protection and computer programs, and a method for locating a fault in a series-compensated two-terminal power transmission line including a compensating bank for providing series-compensation to the transmission line. Different subroutines are utilized for locating faults on line segments from the first terminal to the compensating bank and line segments from the second terminal to the compensating bank. A selection is then made in order to determine a valid result. The subroutines utilize three phase currents synchronized measurements from both terminals and a three phase voltage measurements from one terminal for determining the respective per unit distance to a fault.

Abstract: The present invention is concerned with a method for fault location in series compensated power transmission lines with two-end unsynchronized measurement, finding an application in the electrical power sector and for overhead uncompensated and series-compensated transmission lines.

Abstract: 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 (VA1, VB1) measured at the ends (A) and (B), respectively, obtaining the phasor of the positive sequence currents (IA1, IB1) measured at the ends (A) and (B), respectively, determining whether there is a three-phase balanced fault, and using either a first subroutine or a second subroutine (depending on whether or not there is a fault), determining a distance (d) to the fault.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

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: 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 equal to: ( Z _ 1 ? ? ? LB & ? AB = Z _ 1 ? LB ? Z _ 1 ? AB Z _ 1 ? LB + Z _ 1 ? AB ) ? ? ? where ? : Z1AB=impedance for the positive sequence of the extra link, Z1LA=positive-sequence impedance of the healthy line. A compensation is determined for the shunt capacitance with the aid of an equation of the form: B2comp—1(dcomp—1)2+B1comp—1dcomp—1+B0comp—1=0 where: B2comp—1=A2—Recomp—1A00—Imcomp—1?A2—Imcomp—1A00—Recomp—1 B1comp—1=A1—Recomp—1A00—Imcomp—1?A1—Imcomp—1A00—Recomp—1 B0comp—1=A0—Recomp—1A00—Imcomp—1?A0—Imcomp—1A00—Recomp—1.

Abstract: The present invention relates to a method for calculating the distance to fault in a section of a power transmission network, which section is arranged with line terminals at both ends, each terminal including impedance relays (AA, BB), including the steps of, at the occurence of a fault; measuring the apparent impedances by each relay, measuring the relaying currents, determining the type of fault, checking whether the fault involves a fault resistance or not, and, if so, solving a quadratic equation for complex numbers, resolving the quadratic equation for the real and imaginary components, obtaining two quadratic equations for a fault distance in which the coefficients are real numbers, combining the two equations and obtaining a distance to fault, or, if not so, solving a quadratic equation for real numbers, obtaining two solutions for the distance to fault d1, d2 and comparing the solutions as 0<(d1 or d2)<1 pu, where pu is the length of transmission lines between the line terminals.