CN107589344A - A kind of low-voltage power line Fault Locating Method based on probe current frequency analysis - Google Patents

A kind of low-voltage power line Fault Locating Method based on probe current frequency analysis Download PDF

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Publication number
CN107589344A
CN107589344A CN201710830121.2A CN201710830121A CN107589344A CN 107589344 A CN107589344 A CN 107589344A CN 201710830121 A CN201710830121 A CN 201710830121A CN 107589344 A CN107589344 A CN 107589344A
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China
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transmission line
tou
measured
electric capacity
electricity
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王斌
周卫
王晓明
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Electric Power Research Institute of Guangxi Power Grid Co Ltd
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Electric Power Research Institute of Guangxi Power Grid Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • Locating Faults (AREA)

Abstract

The present invention relates to measuring distance of transmission line fault field, more particularly to a kind of low-voltage power line Fault Locating Method based on probe current frequency analysis, the present invention utilizes the inherent characteristic of transmission line of electricity, and the judgement of fault type and fault localization are realized by increasing a TOU.After faulty transmission line is isolated, one voltage pulse is inputted to faulty transmission line by specific TOU, so that faulty transmission line forms a Second-Order RLC Filter Circuit series resonant circuit by trouble point, failure point of power transmission line is calculated to the distance of TOU installation place by the frequency analysis to resonance current signal.TOU principle in the present invention is simple, low cost, and the present invention can also differentiate whether failure is permanent fault, can complete to calculate before the action of transmission line of electricity reclosing, foundation is provided for reclosing order.The present invention is higher for the measurement accuracy of metallic earthing failure and low transition resistance failure.

Description

A kind of low-voltage power line Fault Locating Method based on probe current frequency analysis
Technical field
The present invention relates to measuring distance of transmission line fault field, and in particular to a kind of low pressure based on probe current frequency analysis Feeder line fault localization method.
Background technology
Power circuit（Overhead line, cable）It is the place for being easiest to break down in power system, in order to quickly and accurately Fault point, faulty line being repaired in time, and improving the power supply reliability of power system, it is important that fault localization carries this Task.
Conventional fault locating methods mainly have impedance method, travelling wave ranging method.Impedance method utilizes circuit when failure, root Fault distance is calculated according to the voltage, the electric current that are measured in its side.Usually as an additional function of protection device, take With relatively low and be easy to implement.But its measurement accuracy is relatively low, and DC line is not suitable for it.Travelling wave ranging method is managed according to traveling wave By the calculating of distance is realized, the directly propagation using voltage wave, current wave caused by failure between bus and trouble point is special Property realize fault location, single end distance measurement and both-end distance measuring can be divided into, precision significantly improves compared with impedance method, suitable for it is long away from From circuit.But it needs additional dedicated measurement apparatus, costly.The range accuracy of double-end distance measurement method also relies on circuit both sides Timing tracking accuracy.
The content of the invention
In order to solve the above problems, the invention provides a kind of low-voltage power line event based on probe current frequency analysis Hinder localization method, concrete technical scheme is as follows：
A kind of low-voltage power line Fault Locating Method based on probe current frequency analysis comprises the following steps：
（1）TOU is installed in transmission line of electricity one end to be measured, the TOU includes current transformer TA, electricity Feel Ld, electric capacity Cd, electric capacity charge circuit, first switch S1, single-pole double-throw switch (SPDT) S2；The single-pole double-throw switch (SPDT) S2 includes fixing Hold c ends, the first moved end a ends, the second moved end b ends；One end of the first switch S1 is connected with transmission line of electricity to be measured, first switch The S1 other end is connected with current transformer TA one end, current transformer the TA other end and inductance LdOne end connection, electricity Feel LdThe other end be connected with single-pole double-throw switch (SPDT) S2 the second moved end b ends, electric capacity CdOne end and single-pole double-throw switch (SPDT) S2 consolidate Fixed end c ends connect, electric capacity CdThe other end be connected and be grounded with one end of electric capacity charge circuit, the other end of electric capacity charge circuit It is connected with single-pole double-throw switch (SPDT) S2 the second moved end a ends；
（2）During transmission line of electricity normal operation to be measured, first switch S1 disconnects with transmission line of electricity to be measured, single-pole double-throw switch (SPDT) S2 The first moved end a ends be connected with fixing end c ends, electric capacity charge circuit is to electric capacity CdCharging；
（3）When transmission line of electricity to be measured breaks down, after the first circuit breaker Q F1, the second circuit breaker Q F2 disconnect, protected by circuit The second switch S2 of protection unit IED control TOUs the second moved end b ends and the closure connection of fixing end c ends and first Switch S1 is closed and is connected with transmission line of electricity to be measured；TOU is electric to the transmission line of electricity to be measured release detection broken down Flow signali d；
（4）Current transformer TA gathers probe current signali d, and be conveyed to line protective devices IED and analyzed, calculated The distance of trouble point to TOU installation place.
Further, the electric capacity charge circuit includes battery and resistance Rd, the battery and resistance RdIt is connected in series.
Further, the TOU also includes control device, and the control device calculates for backstage circuit monitoring Machine or line protective devices.
Further, the step（4）Line protective devices IED is specifically analyzed, calculation procedure includes：
（1）Establish model：The circuit equivalent model of transmission line of electricity to be measured established TOU and broken down, described etc. Effect model is rlc circuit model, establishes the KVL equations of rlc circuit model, as follows：
；
Wherein, R=R1+Rf, R1For failure point of power transmission line to be measured to the equivalent resistance between TOU installation place, RfFor The transition resistance of failure point of power transmission line to be measured；
L=L1+Ld, L1For failure point of power transmission line to be measured to the equivalent inductance between TOU installation place, LdFor failure The inductance L of detection deviced；
C=Cd, CdFor the electric capacity C of TOUd；
（2）Ask for probe current signal（i d）Electric currenti dSize：
；
Wherein, U0For the electric capacity C of TOUdVoltage；p1、p2Respectively formulaCharacteristic root；
（3）Suitable electric capacity C is selected to TOUdWith inductance LdSo that rlc circuit is in underdamping state, i.e. R2< 4L/C, then formulaCharacteristic root be：
；
Wherein：
；
（4）By formulaWithCurrent signal must be surveyed by solvingi dElectric currenti dSize is：
；
（5）AdjustmentL/CRatio cause ωd≈ω0, then：
；
（6）Due to ωd=2πf idAnd L1=dLμ, then the distance d of failure point of power transmission line to be measured to TOU installation place For：
；
Wherein, by probe current signali dCarry out Fast Fourier Transform (FFT) and obtain probe current signali dPower frequencyf id, LμFor the inductance value of transmission line of electricity unit length to be measured.
Beneficial effects of the present invention are：The present invention utilizes the inherent characteristic of transmission line of electricity, by increasing a fault-finding Device realizes the judgement of fault type and fault localization.After faulty transmission line is isolated, pass through specific fault-finding Device inputs a voltage pulse to faulty transmission line so that faulty transmission line forms a Second-Order RLC Filter Circuit by trouble point Series resonant circuit, failure point of power transmission line is calculated to TOU by the frequency analysis to resonance current signal The distance of installation place.TOU principle in the present invention is simple, low cost, the present invention can also differentiate failure whether be Permanent fault, it can complete to calculate before the action of transmission line of electricity reclosing, foundation is provided for reclosing order.The present invention for The measurement accuracy of metallic earthing failure and low transition resistance failure is higher.
Brief description of the drawings
Fig. 1 is the operation principle schematic diagram of the TOU of the present invention；
Fig. 2 is the rlc circuit modular concept schematic diagram in the present invention；
Fig. 3 is the waveform diagram of probe current signal in the present invention；
Fig. 4 is the result schematic diagram of the Fast Fourier Transform (FFT) to probe current signal in the present invention.
Embodiment
In order to be better understood from the present invention, the invention will be further described with specific embodiment below in conjunction with the accompanying drawings：
As shown in figure 1, a kind of low-voltage power line Fault Locating Method based on probe current frequency analysis comprises the following steps：
1st, TOU is installed in transmission line of electricity one end to be measured, TOU includes current transformer TA, inductance Ld、 Electric capacity Cd, electric capacity charge circuit, first switch S1, single-pole double-throw switch (SPDT) S2；Single-pole double-throw switch (SPDT) S2 includes fixing end c ends, the One moved end a ends, the second moved end b ends；One end of the first switch S1 is connected with transmission line of electricity to be measured, and first switch S1's is another End is connected with current transformer TA one end, current transformer the TA other end and inductance LdOne end connection, inductance LdIt is another End is connected with single-pole double-throw switch (SPDT) S2 the second moved end b ends, electric capacity CdOne end and single-pole double-throw switch (SPDT) S2 fixing end c ends connect Connect, electric capacity CdThe other end be connected and be grounded with one end of electric capacity charge circuit, the other end of electric capacity charge circuit is double with hilted broadsword Throw switch S2 the second moved end a ends connection；Electric capacity charge circuit includes battery and resistance Rd, battery and resistance RdSeries connection connects Connect；Resistance RdEffect be limiting capacitance CdCharging current, avoid electric capacity CdCharging current it is excessive；TOU is also Including control device, control device is line protective devices IED；
2nd, during transmission line of electricity normal operation to be measured, first switch S1 disconnects with transmission line of electricity to be measured, single-pole double-throw switch (SPDT) S2 The first moved end a ends be connected with fixing end c ends, electric capacity charge circuit is to electric capacity CdCharging；
3rd, when transmission line of electricity to be measured breaks down, after the first circuit breaker Q F1, the second circuit breaker Q F2 disconnect, by route protection The second switch S2 of device IED control TOUs the second moved end b ends close connection with fixing end c ends and first opens S1 is closed to close and be connected with transmission line of electricity to be measured；TOU discharges probe current to the transmission line of electricity to be measured to break down Signali dIf transient fault occurs for transmission line of electricity, the probe current value for the probe current signal that TOU is sent is Zero, if permanent fault occurs for transmission line of electricity, TOU and the transmission line of electricity to be measured to break down form loop, production Raw probe currenti d,
4th, current transformer TA gathers probe current signali d, and be conveyed to line protective devices IED and analyzed, calculate event Hindering point to the distance of TOU installation place, specific steps includes：
（1）Establish model：Establish TOU and the circuit equivalent model of the transmission line of electricity to be measured to break down, equivalent mould Type is rlc circuit model, as shown in Fig. 2 now there was only electric capacity CdInitial voltage be present, therefore fault-finding process is actually It is the order input respective process of Second-Order RLC Filter Circuit circuit, establishes the KVL equations of rlc circuit model, it is as follows：
；
Wherein, R=R1+Rf, R1For failure point of power transmission line to be measured to the equivalent resistance between TOU installation place, RfFor The transition resistance of failure point of power transmission line to be measured；
L=L1+Ld, L1For failure point of power transmission line to be measured to the equivalent inductance between TOU installation place, LdFor failure The inductance L of detection deviced；
Because the electric capacity C of TOUdMuch larger than the direct-to-ground capacitance of transmission line of electricity, then C=Cd, CdFor TOU Electric capacity Cd；
（2）Ask for probe current signal（i d）Electric currenti dSize：
；
Wherein, U0For the electric capacity C of TOUdVoltage；Determined by the voltage of battery, p1、p2Respectively formula Characteristic root；
（3）Because TOU selects suitable electric capacity CdWith inductance LdIts size can be controlled, so giving fault-finding Device selects suitable electric capacity CdWith inductance LdSo that rlc circuit is in underdamping state, i.e. R2<4L/C, then formulaFeature Root is：
；
Wherein：
；
（4）By formulaWithCurrent signal must be surveyed by solvingi dElectric currenti dSize is：
；
（5）By formulaUnderstand, as long as reducing as far as possibleζ, i.e., increase as far as possibleL/CRatio i.e. may be such that ωd≈ ω0, so adjustmentL/CRatio cause ωd≈ω0, then：
；
（6）Due to ωd=2πf idAnd L1=dLμ, then the distance d of failure point of power transmission line to be measured to TOU installation place For：
；
Wherein, by probe current signali dCarry out Fast Fourier Transform (FFT) and obtain probe current signali dPower frequencyf id, LμFor the inductance value of transmission line of electricity unit length to be measured.
For the feasibility of the further checking present invention, emulated underneath with MATLAB and data processing, parameter setting As shown in table 1：
One total length of analogue simulation is that 2km power cable breaks down, and trouble point is disposed therein place, and failure transition is electric Hinder and as shown in Figure 2, the result such as institute of accompanying drawing 4 of Fast Fourier Transform (FFT) is carried out to probe current for 0.1 Ω, probe current waveform Show, the distance measurement result of emulation isd=0.997km, fault location error are 0.3%, demonstrate the feasibility of the present invention.
The present invention is not limited to above-described embodiment, the foregoing is only the preferable case study on implementation of the present invention , it is not intended to limit the invention, any modification for being made within the spirit and principles of the invention, equivalent substitution and changes Enter, should be included in the scope of the protection.

Claims (4)

  1. A kind of 1. low-voltage power line Fault Locating Method based on probe current frequency analysis, it is characterised in that：Including following Step：
    （1）TOU is installed in transmission line of electricity one end to be measured, the TOU includes current transformer（TA）、 Inductance（Ld）, electric capacity（Cd）, electric capacity charge circuit, first switch（S1）, single-pole double-throw switch (SPDT)（S2）；The single-pole double-throw switch (SPDT) （S2）Including fixing end（C ends）, the first moved end（A ends）, the second moved end（B ends）；The first switch（S1）One end with it is to be measured Transmission line of electricity connects, first switch（S1）The other end and current transformer（TA）One end connection, current transformer（TA）'s The other end and inductance（Ld）One end connection, inductance（Ld）The other end and single-pole double-throw switch (SPDT)（S2）The second moved end（B ends）Even Connect, electric capacity（Cd）One end and single-pole double-throw switch (SPDT)（S2）Fixing end（C ends）Connection, electric capacity（Cd）The other end filled with electric capacity One end of electrical circuit connects and is grounded, the other end and single-pole double-throw switch (SPDT) of electric capacity charge circuit（S2）The second moved end（A ends） Connection；
    （2）During transmission line of electricity normal operation to be measured, first switch（S1）Disconnected with transmission line of electricity to be measured, single-pole double-throw switch (SPDT) （S2）The first moved end（A ends）With fixing end（C ends）Connection, electric capacity charge circuit is to electric capacity（Cd）Charging；
    （3）When transmission line of electricity to be measured breaks down, the first breaker（QF1）, the second breaker（QF2）After all disconnecting, by line Line protection device（IED）Control the second switch of TOU（S2）The second moved end（B ends）With fixing end（C ends）Closure Connection and first switch（S1）Close and be connected with transmission line of electricity to be measured；TOU is to the transmission of electricity to be measured broken down Circuit discharges probe current signal（i d）；
    （4）Current transformer（TA）Gather probe current signal（i d）, and it is conveyed to line protective devices（IED）Analyzed, counted Trouble point is calculated to the distance of TOU installation place.
  2. 2. a kind of low-voltage power line Fault Locating Method based on probe current frequency analysis according to claim 1, It is characterized in that：The electric capacity charge circuit includes battery and resistance（Rd）, the battery and resistance（Rd）It is connected in series.
  3. 3. a kind of low-voltage power line Fault Locating Method based on probe current frequency analysis according to claim 1, It is characterized in that：The TOU also includes control device, the control device be backstage circuit monitoring computer or Line protective devices.
  4. 4. a kind of low-voltage power line Fault Locating Method based on probe current frequency analysis according to claim 1, It is characterized in that：The step（4）Line protective devices（IED）Specific analysis, calculation procedure include：
    （1）Establish model：The circuit equivalent model of transmission line of electricity to be measured established TOU and broken down, described etc. Effect model is rlc circuit model, establishes the KVL equations of rlc circuit model, as follows：
    ；
    Wherein, R=R1+Rf, R1For failure point of power transmission line to be measured to the equivalent resistance between TOU installation place, RfFor The transition resistance of failure point of power transmission line to be measured；
    L=L1+Ld, L1For failure point of power transmission line to be measured to the equivalent inductance between TOU installation place, LdVisited for failure Survey the inductance of device（Ld）；
    C=Cd, CdFor the electric capacity of TOU（Cd）；
    （2）Ask for probe current signal（i d）Electric currenti dSize：
    ；
    Wherein, U0For the electric capacity of TOU（Cd）Voltage；p1、p2Respectively formulaCharacteristic root；
    （3）Suitable electric capacity is selected to TOU（Cd）And inductance（Ld）So that rlc circuit is in underdamping state, i.e., R2<4L/C, then formulaCharacteristic root be：
    ；
    Wherein：
    ；
    （4）By formulaWithCurrent signal must be surveyed by solving（i d）Electric currenti dSize is：
    ；
    （5）AdjustmentL/CRatio cause ωd≈ω0, then：
    ；
    （6）Due to ωd=2πf idAnd L1=dLμ, then the distance d of failure point of power transmission line to be measured to TOU installation place For：
    ；
    Wherein, by probe current signal（i d）Carry out Fast Fourier Transform (FFT) and obtain probe current signali dPower frequencyf id, LμFor the inductance value of transmission line of electricity unit length to be measured.
CN201710830121.2A 2017-09-15 2017-09-15 A kind of low-voltage power line Fault Locating Method based on probe current frequency analysis Pending CN107589344A (en)

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Publication number Priority date Publication date Assignee Title
CN108594067A (en) * 2018-04-02 2018-09-28 湖南大学 A kind of Multi-port direct-current distribution network line short fault distance measuring method
CN109342888A (en) * 2018-11-23 2019-02-15 上海电力学院 A kind of single-ended fault positioning method for transmission line based on reclosing motion analysis
CN110542834A (en) * 2019-09-30 2019-12-06 国家电网有限公司 direct-current power distribution network double-end ranging fault positioning method based on improved injection method
CN111060782A (en) * 2020-01-07 2020-04-24 北京海兰信数据科技股份有限公司 Cable simulation device of power transmission system for submarine observation network

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CN107064734A (en) * 2017-03-17 2017-08-18 北京交通大学 A kind of flexible direct current Fault Location for Distribution Network method of utilization fault transient process
CN107085169A (en) * 2017-05-16 2017-08-22 华北电力大学 A kind of Fault Locating Method of flexible direct current distribution line

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108594067A (en) * 2018-04-02 2018-09-28 湖南大学 A kind of Multi-port direct-current distribution network line short fault distance measuring method
CN109342888A (en) * 2018-11-23 2019-02-15 上海电力学院 A kind of single-ended fault positioning method for transmission line based on reclosing motion analysis
CN109342888B (en) * 2018-11-23 2020-10-23 上海电力学院 Single-ended power transmission line fault location method based on reclosing action analysis
CN110542834A (en) * 2019-09-30 2019-12-06 国家电网有限公司 direct-current power distribution network double-end ranging fault positioning method based on improved injection method
CN111060782A (en) * 2020-01-07 2020-04-24 北京海兰信数据科技股份有限公司 Cable simulation device of power transmission system for submarine observation network

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