RU-2861653-C1 - METHOD FOR DETERMINING FAULT LOCATION ON DOUBLE-CIRCUIT OVERHEAD POWER LINE

RU2861653C1RU 2861653 C1RU2861653 C1RU 2861653C1RU-2861653-C1

Abstract

FIELD: electric power industry. SUBSTANCE: invention can be used to determine the fault location on double-circuit overhead power lines when quadratic equations are used to calculate the distance to the fault. The essence of the claimed solution lies in the fact that to determine the fault location on double-circuit overhead power lines, the inductive coupling between the circuits of the overhead power line is taken into account when calculating the distance to the fault, additionally the negative and zero sequence components of the recorded currents at the measurement point are used, as well as the zero sequence resistance of the overhead power line and the sources at its ends, the zero sequence currents of the first and second circuits of the overhead power line are measured from the measurement point side, parameters B 1 and C 1 included in the quadratic equation are determined, the quadratic equation is solved, the fault location corresponding to and the fault location at the measurement point are identified by the operation of the differential protection of the bus(es) to which the double-circuit overhead power line is connected from the measurement point side, in the absence of operation of the bus differential protection, the fault location on the power line is unambiguously determined at a distance of from the measurement point. EFFECT: development of a method in which the calculation of the distance to the fault location of a double-circuit overhead power line is carried out based on a quadratic equation and which provides an unambiguous solution regarding the fault location on the line. 1 cl, 1 dwg, 1 tbl

Inventors

KULIKOV ALEKSANDR LEONIDOVICH
Fedosov Denis Sergeevich
Kriukov Evgenii Valerevich

Dates

Publication Date: 20260506
Application Date: 20251029

Claims (12)

A method for determining the location of a fault on a double-circuit overhead power line located between a network behind said power line and a network located in front of said power line, in which the currents and voltages in the line are measured at one end of said power line, the distance between the measurement point and the fault point is calculated using the measured values and parameters of said power line, the type of fault is determined, the values of the measured currents and voltages corresponding to the fundamental frequency of the power network are determined, the type of fault and the complex components of the currents and voltages of the fundamental frequency of the power network and the model of the power network are used, the value of the resistance of the power line is used, as well as the value of the resistance of the sources at its ends, the influence of the fault resistance is eliminated, the distance to the fault location is calculated ( ) from the measurement point, determined by the solution of a quadratic equation, which contains the distance to the damage location ( ) as a variable, as well as parameters And , which depend on the measured values of the components of the currents and voltages of the fundamental frequency, on the specified resistances and the distance from the measurement point to the location of the fault ( )
characterized in that they take into account the inductive coupling between the circuits of the overhead power line when calculating the distance to the fault location, additionally use the components of the negative and zero sequences of the recorded currents at the measurement point, as well as the zero sequence resistance of the overhead power line and the sources at its ends, and measure the currents And − zero-sequence currents of the first ( ) and the second ( ) overhead power line circuits from the measurement point, and the coefficients , , , which are part of the quadratic equation, are determined as follows:
;
Where , , – respectively, the resistance of the direct sequence systems and the overhead power line; And – voltage and current at the measurement point, taking into account the type of damage; – negative sequence current at the measurement point; , - circuit compensation coefficients, which also take into account the mutual influence of zero-sequence resistances between the first and second circuits of the overhead power transmission line;
determine the parameters And , which are part of the quadratic equation, where
; ;
; ; ;
Where , , – respectively, the zero-sequence resistance of the systems and the overhead power transmission line; – zero-sequence current at the measurement point (circuit );
solve a quadratic equation
,
identify the location of damage corresponding to the root of the quadratic equation and the location of the fault at the measurement point, upon the operation of the differential protection of the bus(es) to which the overhead double-circuit power transmission line is connected from the side of the measurement point, in the event of no operation of the differential protection of the bus, the location of the fault in the power transmission line is clearly determined at a distance
from the measurement point.

Description

The proposed invention relates to the electric power industry and can be used to determine the fault location (FLO) on double-circuit overhead power lines (OPL), when quadratic equations are used to calculate the distance to the fault location. A method for determining the location of damage on overhead power lines (variants) is known [RU Patent 2526095, IPC G01R 31/08, published 20.08.2014 Bulletin No. 23]. According to the method, in one of the variants for a double-circuit overhead power line, the fault location is implemented, for example, as follows: 1. At the moment preceding a short circuit (SC), the pre-emergency load currents are measured at the beginning of the line and the end of the line and the values of the direct sequence of the fundamental harmonic of the load current from one and the other end of the line in the first and second circuits of the line are determined; 2. At the moment of short circuit, the first harmonic of phase currents at the beginning of the line, phase currents at the end of the line, phase voltages at the beginning of the line, and phase voltages at the end of the line are measured and determined; 3. Transmit phase currents of the first harmonic from the beginning of the line to the end of the line and phase currents of the first harmonic from the end of the line to the beginning of the line via communication channels; 4. At each end of the line, the currents of the direct, zero and reverse sequences of the beginning and end of the line are determined; 5. Based on the values obtained in the previous paragraphs and the expressions in the table, the values required to implement the OMP are determined at the first and second ends of the damaged line circuit. 6. In the event of damage to both the first and second circuits of the line, the distance from the beginning of the line to the location of damage (at the beginning of the line) is determined in relative units and the distance from the end of the line to the location of damage (at the end of the line) is determined in relative units. However, the known method does not use quadratic equations to calculate the distance to the fault location on a double-circuit overhead power line. A method for locating faults on overhead power lines is known [RU Patent 2426998, IPC G01R 31/08, published 20.08.2011 Bulletin No. 23]. According to this method, based on measured phase currents and voltages at the moment of a short circuit and the load current in pre-emergency mode, telegraph equations are used to obtain an approximate distance to the fault location. Then, through an iterative process, varying the contact resistance at the fault location, taking into account the transverse capacitance of the line, wave processes, and the criterion that the imaginary part of the distance to the fault location tends to zero, the distance to the fault location is refined. Although the known method is applicable for fault detection on double-circuit overhead power lines, it does not use quadratic equations to calculate the distance to the fault location. The closest technical solution to the proposed invention is a method for determining the location of a fault in a three-phase power transmission line [Patent US 4559491, IPC G01R 31/08, published 12/17/1985], located between the network behind the said power transmission line and the network located in front of the said power transmission line, in which the currents and voltages in the line are measured at one end of the said power transmission line, the distance between the measurement point and the fault point is calculated using the measured values and parameters of the said power transmission line, the type of fault is determined, the values of the measured currents and voltages corresponding to the fundamental frequency of the electrical network are determined, the type of fault and the complex components of the currents and voltages of the fundamental frequency of the electrical network and a model of the electrical network that takes into account the influence of the electrical network in front of the said power transmission line are used, the value of the resistance of the power transmission line is used, as well as the value of the resistance of the sources at its ends, zero-sequence components are excluded from the fault current and only positive-sequence components are used, the influence of the fault resistance is eliminated, the distance to the fault location is calculated ( ) from the measurement point, determined by the solution of the quadratic equation (*) which contains the distance to the damage site ( ) as a variable, as well as parameters And , which depend on the measured values of the components of the currents and voltages of the fundamental frequency, on the specified resistances and the distance from the measurement point to the location of the fault ( ) ; ; ; ; ; ; , Where And – voltage and current at the measurement point ; – resistance of the source from the measuremen