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RU-2861610-C1 - METHOD FOR DETERMINING FAULT LOCATION ON OVERHEAD POWER LINE

RU2861610C1RU 2861610 C1RU2861610 C1RU 2861610C1RU-2861610-C1

Abstract

FIELD: electric power industry. SUBSTANCE: invention can be used to determine the fault location on overhead power lines. The method for determining the fault location consists of measuring currents and voltages at one end of the power line, determining the type of damage, not taking into account the fault resistance, performing a calculation by solving an equation which contains parameters and , depending on the values of the fundamental frequency current and voltage components, the resistances of the sources at the ends of the power line and the power line itself. Additionally, the zero-sequence current and parameters are used, parameters and are determined, a quadratic equation is solved, the fault location is established by the operation of the differential protection, in the absence of protection operation, the fault location is established at a distance from the measurement point . EFFECT: unambiguous determination of the fault location. 1 cl, 1 dwg, 1 tbl

Inventors

  • KULIKOV ALEKSANDR LEONIDOVICH
  • Denis Sergeevich Fedosov
  • Kriukov Evgenii Valerevich

Dates

Publication Date
20260506
Application Date
20251029

Claims (14)

  1. A method for determining the location of a fault on an 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 a model of the power network that takes into account the influence of the power network in front of said power line 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 resistance of the fault is eliminated, the distance to the fault location is calculated ( ) from the measurement point, determined by the solution of a quadratic equation that contains the distance to the location of damage ( ) 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 ( ),
  2. ; ;
  3. ; ; ;
  4. ; ; ,
  5. Where And – voltage and current at the measurement point ; – resistance of the source from the measurement point ; – the resistance of the source from the remote end of the power line (point ); – resistance of the power transmission line; – change in current at the measurement point as a result of damage to the power line (purely emergency current),
  6. characterized in that, to make an unambiguous decision regarding the location of the fault on the line, the zero-sequence current at the measurement point is additionally used , as well as the parameters of the zero sequence of sources and the overhead power line, determine the parameters And , which are part of the quadratic equation, where
  7. ; ;
  8. ; ; ;
  9. ; ; ,
  10. Where – zero-sequence current at the measurement point ; – zero sequence resistance of the power transmission line; And – zero-sequence resistance of sources at the ends of the line,
  11. solve a quadratic equation
  12. ,
  13. identify the location of damage corresponding to the root of the quadratic equation and the location of the damage at the measurement point , upon activation of the differential protection of the busbar(s) to which the power transmission line is connected from the point side , in the event of no operation of the differential protection of the busbar, the location of the damage to the power line is clearly determined at a distance
  14. from the measurement point .

Description

The proposed invention relates to the electric power industry and can be used to determine the location of damage on overhead power lines when quadratic equations are used to calculate the distance to the location of damage. A method is known for determining the location of damage during short circuits on a high-voltage direct current power transmission line (HVDC) [Author's Certificate SU 177710, IPC G01R 31/08, published 23.11.92, Bulletin No. 43], containing filters for higher harmonic components of voltage, which consists of recording the shape of the line voltage curve of the damaged transmission pole, extracting from it the informative part of the emergency component of the signal, determining the spectral characteristics of this component and extracting the frequency in it with the greatest amplitude corresponding to the oscillatory process of line discharge through the fault location. According to the method, attenuation is additionally determined oscillatory process for the transient frequency component , and, taking into account the value of the equivalent inductance of the converter and the parameters of the filters of higher harmonic components determine the distance as the real part of the quantity Where - complex coefficient; - complex coefficient; - complex coefficient; - operator; - operator expression of the admittance of the equivalent circuit of high-harmonic filters; - the speed of the electromagnetic wave in the wire-ground circuit at a frequency , km/s; , , - linear parameters of the line in the wire-ground circuit at a frequency ; - attenuation of the oscillatory process of line discharge; - inductance of the converter circuit; , - successive amplitudes of the transient component of voltage; - time interval between amplitudes And . Calculating the distance to the fault location using the known method is based on solving a quadratic equation. However, this method is only applicable to high-voltage direct current (HVDC) power lines and is not applicable to high-voltage alternating current (AC) power lines. A system is known for determining fault locations and estimating fault resistance in distribution networks with a diverting load [Patent US 5839093, IPC H02H 3/26, published 11/17/1998], which includes a method for determining fault locations and estimating fault resistance in a distribution network with a feeder having a diverting load, including: a) obtaining known circuit parameters, including measuring current before and after fault and voltage values at a monitored location on said feeder; b) calculating load resistance and source resistance And from the known circuit parameters measured in step a); c) determining equations that take into account the effect of the fault resistance and the change in load current caused by the fault and that relate the fault location to the known circuit parameters without estimating the fault resistance and without using its reactive component; d) solving the equations of step c) to obtain the distance to the fault location. When implementing the method, the specific resistance of the distribution network is determined. , and the load resistance is also calculated and source resistance from the current and voltage values before and after the fault, recorded at the measurement location. Calculation of the distance to the fault location is produced by solving a quadratic equation with respect to , having the form Where ; ; ; - the relative distance to the damage location, expressed as a fraction of the length of the distribution network line; - damage resistance; - post-accident voltage; - post-accident current; And - pre-emergency current and voltage; - specific resistance of the distribution network line; - source resistance; - load resistance; ; ; ; . Calculating the distance to the fault location using a known method is based on solving a quadratic equation. However, it is possible that both roots of the quadratic equation may be located within the faulted power line. In such cases, there is no definitive solution regarding the fault location. It should also be noted that the known method is implemented only on transmission lines with one-way power supply (dead-end lines). A method is known for determining the location of a fault on an overhead power transmission line equipped with a ground wire [RU Patent 2834732, IPC G01R 31/08, published 13.02.2025, Bulletin No. 5], according to which the faulty phase of the power transmission line is determined, the phase voltages and currents of the emergency and pre-emergency modes at the beginning of the power transmission line are measured, the symmetrical components of the currents are determined from the measured phase currents, the purely emergency positive sequence current is determined as the difference between the positive sequence currents of the emergency and pre-emergency modes, and a reference current is used in the expression for calculating the distance to the fault location, which is selecte