CN115184718B - Three-core cable fault positioning method based on time domain analysis - Google Patents
Three-core cable fault positioning method based on time domain analysis Download PDFInfo
- Publication number
- CN115184718B CN115184718B CN202210414945.2A CN202210414945A CN115184718B CN 115184718 B CN115184718 B CN 115184718B CN 202210414945 A CN202210414945 A CN 202210414945A CN 115184718 B CN115184718 B CN 115184718B
- Authority
- CN
- China
- Prior art keywords
- phase
- fault
- shielding layer
- metal shielding
- virtual
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000004364 calculation method Methods 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims description 71
- 239000013598 vector Substances 0.000 claims description 27
- 239000004020 conductor Substances 0.000 claims description 7
- 239000013256 coordination polymer Substances 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 4
- 238000004088 simulation Methods 0.000 abstract description 2
- 230000006870 function Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 101100499229 Mus musculus Dhrsx gene Proteins 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 240000005373 Panax quinquefolius Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008447 perception Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Locating Faults (AREA)
Abstract
Firstly, calculating the voltage between a three-phase wire core and a shielding layer at a virtual fault point and the current of the three-phase wire core flowing to the shielding layer by using wire core current, ground voltage and ground wire current time domain signals measured at the head end and the tail end of a cable circuit after the fault occurs; then, estimating virtual fault resistance between the three-phase wire core and the shielding layer at the virtual fault point, calculating integral of voltage difference between the three-phase wire core and the shielding layer at the virtual fault point in a period of time, and determining virtual fault distance corresponding to the integral minimum value when the virtual fault point changes within the full length range of the line; and finally, determining a fault phase by comparing the average value of the three-phase virtual fault resistances obtained by calculation at the virtual fault distance within a period of time, wherein the minimum virtual fault distance corresponding to the fault is the actual fault distance. The simulation shows that the method can accurately identify the fault phase and the fault accurate position under different fault conditions, and has higher engineering application value.
Description
Technical Field
The invention relates to the technical field of power grid equipment fault investigation, in particular to a three-core cable fault positioning method based on time domain analysis.
Background
With the acceleration of the urban process, the occupied weight of the cable in urban network power supply is heavier and heavier, and the cable gradually replaces an overhead power supply line and is widely applied to power distribution networks. The cable lines are easy to cause faults due to external force, environment and other factors, and most of the cable lines are laid underground, so that fault searching is difficult. In order to improve operation and maintenance efficiency, improve the cable fault perception level of the distribution network, ensure the safe and stable operation of the distribution network, the three-wire cable fault positioning is imperative.
At present, only a fault locating method aiming at a medium-voltage and high-voltage single-core cable line exists, but an effective fault locating method aiming at a three-core cable structure is not provided yet. The single-core cable fault positioning method is mainly divided into two types: traveling wave methods and impedance methods. The traveling wave method mainly utilizes the relation between the arrival time of the wave head and the fault distance to realize positioning; the impedance rule utilizes steady-state voltage and current phasors at one end or two ends of a line, and realizes positioning by solving an equation (system) containing fault distance and line parameters. The literature (Deng Feng, li Xinran, zeng Xiangjun, electrician technical school) discloses a method for locating single-ended traveling wave of a series-parallel line based on full-waveform information, which constructs traveling wave time-frequency energy spectrum matrixes at different fault positions and under fault conditions, and the fault positions of the cable-overhead series-parallel line are determined by comparing full-waveform energy correlations at different positions. The literature (Shu Hongchun, tian Xincui, dong Jun, yang Yi, chinese motor engineering theory) adopts TT transformation to accurately mark the arrival time of two traveling wave heads, and adopts a single-end method to realize single-core cable fault accurate distance measurement. Literature (Tang Jin, zhang Shu, lin Sheng, he Zhengyou, chinese motor engineering theory) discloses a single-end fault location method for cables which takes into account a metal sheath structure, wherein the accurate fault location of a single core is determined by iterating the difference values of the steady-state components of the normal phase core and sheath current faults before and after the fault point.
Unlike single core cables, three core cables are complex in structure, there is strong electromagnetic coupling between the three phase conductor and the metal shielding layer, and the fault locating method proposed by the existing research cannot be applied to such complex situation. In addition, as the distance of the three-core cable line is short, the traveling wave head is difficult to identify, and the significance of researching the traveling wave method is not great; although the impedance method does not need to identify the traveling wave head, the actual steady-state fault signal can not be obtained sometimes, and the value of researching the impedance method is not high. Therefore, the fault locating method for realizing the three-core cable by using the fault time domain signal based on the fault time domain equivalent model has important value and significance.
Disclosure of Invention
In order to solve the defects existing in the existing researches about cable fault location, a three-core cable fault location method based on time domain analysis is provided.
A three-core cable fault positioning method based on time domain analysis comprises the following steps:
step 1, after a three-core cable fails, measuring three-phase core current, core-to-ground voltage and ground wire current at the head end of a line, and three-phase core current, core-to-ground voltage and shield layer-to-ground voltage at the tail end of the line, so as to obtain line impedance and ground wire resistance;
step 2, intercepting an effective time window [ t ] for all acquired currents and voltages 1 ,t 2 ]A signal within; wherein t is 1 And t 2 The starting time and the ending time of the effective time window are respectively;
step 3, enabling the initial value of the distance x between the virtual fault point and the line head end to be 0;
step 4, bringing the current and voltage signals measured by the head end of the line into the following steps to calculate the voltage signals u to ground of the phase A, the phase B and the phase C of the virtual fault point and the metal shielding layer LFAG (t,x)、 u LFBG (t,x)、u LFCG (t, x) and u LFSG (t,x)：
Wherein u is LA (t)、u LB (t)、u LC (t) and i LS (t) is the signal of the earth voltage and the earth wire current of the leading cores of the phase A, the phase B and the phase C of the line head end after the fault occurs, i LP (t) and i LS (t) is the current of the P-phase conducting core at the head end of the line after the fault and the current signal of the grounding wire, P is { A, B, C }, R AP 、R BP 、R CP 、R SP The mutual resistances between the phase A, the phase B, the phase C and the metal shielding layer and the phase P conducting core are respectively R AS 、R BS 、R CS The mutual resistances between the phase A, phase B and phase C conducting cores and the metal shielding layer are respectively R SS Is the self-resistance of the metal shielding layer, R S L is the resistance of the grounding wire AP 、L BP 、L CP 、L SP Mutual inductance between phase A, phase B, phase C and metal shielding layer and phase P, L AS 、L BS 、L CS Mutual inductance between the phase A, phase B and phase C conductive cores and the metal shielding layer, L SS Self-electricity for metal shielding layerFeel is felt;
step 5, according to u LFAG (t,x)、u LFBG (t,x)、u LFCG (t, x) and u LFSG (t, x) calculating the voltage signals u between the A-phase, B-phase, C-phase conductive cores and the metallic shielding layer at the virtual fault point LFAS (t,x)、u LFBS (t,x)、u LFCS (t,x)；
Step 6, the current and voltage signals measured at the tail end of the line are brought into the following steps to calculate the voltage signals u to the ground of the phase A, the phase B and the phase C of the conducting core and the metal shielding layer at the virtual fault point RFAG (t,x)、 u RFBG (t,x)、u RFCG (t, x) and u RFSG (t,x)：
Wherein u is RA (t)、u RB (t)、u RC (t) and u S (t) the voltages of the conducting cores of the phase A, the phase B and the phase C at the tail end of the line and the metal shielding layer after the fault occurs are respectively the voltages of the conducting cores of the phase A, the phase B and the phase C and the voltages of the metal shielding layer and i RP (t) P-phase conductor current at the tail end of the line after the fault occurs, and l is the total length of the line;
step 7, according to u RFAG (t,x)、u RFBG (t,x)、u RFCG (t, x) and u RFSG (t, x) calculating the voltage signals u between the A-phase, B-phase, C-phase conductive cores and the metallic shielding layer at the virtual fault point RFAS (t,x)、u RFBS (t,x)、u RFCS (t,x)；
Step 8, calculating the current signal i of the phase A, the phase B and the phase C flowing to the metal shielding layer at the virtual fault point x according to the following formula FAS (t,x)、i FBS (t,x)、i FCS (t,x)：
Step 9, according to the voltage signal u LFAS (t,x)、u LFBS (t,x)、u LFCS (t, x) and current signal i FAS (t,x)、i FBS (t,x)、i FCS (t, x) calculating virtual fault pointsVirtual fault resistor R between phase A, phase B and phase C conducting core and metal shielding layer FAS (t,x)、R FBS (t,x)、R FCS (t,x)；
Step 10, the calculation results of the step 5 and the step 7 are carried into the following formula, and absolute differences of voltages between the phase A, phase B, phase C conducting cores and the metal shielding layer at the virtual fault point are calculated in an effective time window [ t ] 1 ,t 2 ]Integral D in A (x)、D B (x)、D C (x)：
Step 11, if the virtual fault distance x is less than or equal to the total length l of the line, let x=x+1m, and repeatedly execute steps 4 to 10; otherwise, the following vectors are obtained:
wherein R is FPS (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the virtual fault resistance vector between the P-phase conducting core and the metal shielding layer, D P (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the absolute difference of the voltages between the P-phase conducting core and the metal shielding layer is the integral vector, N x Function F for the total number of virtual fault points set on the line z () For taking an integer part of a real number;
step 12, determining the vector R according to the result of step 11 FPS (t 2 ) Average value of (D) and vector D P (t 2 ) Is respectively denoted as R FPS_mean (t 2 ) And D P_min (t 2 )；
Step 13, if the expiration time t of the effective time window 2 Less than or equal to the effective time window starting time t 1 Total length of shift T of data window t And, thenLet t 1 ＝t 1 +δ，t 2 ＝t 2 +δ, δ represents the amount of shift per time window, repeatedly performing steps 3 to 12; otherwise, the following vectors are obtained:
wherein R is FPS Represents a virtual fault resistance average vector, D, between the P-phase conducting core and the metal shielding layer at different effective time window ending moments and virtual fault distances P An integral minimum vector, N, of absolute difference values of voltages between the P-phase conducting core and the metal shielding layer in the effective time window under different effective time window ending moments and virtual fault distances t The total number of the set different effective time window ending moments;
step 14, determining the vector R according to the result of step 13 FPS Average value of (1) is denoted as R FPS_mean ；
And 15, identifying a fault phase by using the following criteria, and estimating fault resistance:
wherein the function min () is used for the determined R FAS_mean 、R FBS_mean And R is FCS_mean The minimum of the three numbers and the corresponding index (A, B, C);
step 16, calculating the actual fault accurate distance x by using the following method F ：
Wherein k is a continuous variable and k ε Z + 。
Further, in step 2 and step 13, the start-stop time of the effective time window and the total length of the data window shift are determined according to the following formula:
wherein t is 0 The arrival time of the traveling wave head can be obtained by a wavelet mode maximum value method; t (T) t The total length is shifted for the data window.
Further, in step 5, the result of step 4 is taken into the following formula, and voltage signals between the a-phase, B-phase, C-phase conductive cores and the metal shielding layer at the virtual fault point are calculated:
wherein u is LFAS (t,x)、u LFBS (t,x)、u LFCS And (t, x) are voltage signals between the phase A, phase B and phase C conducting cores and the metal shielding layer at the virtual fault point obtained by calculation by using the current and voltage signals measured by the head end of the line.
Further, in step 7, the result of step 6 is taken into the following formula, and voltage signals between the a-phase, B-phase, C-phase conductive cores and the metal shielding layer at the virtual fault point are calculated:
wherein u is RFAS (t,x)、u RFBS (t,x)、u RFCS (t, x) are voltage signals between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point calculated by using the current and voltage signals measured by the line end.
Further, in step 9, the calculation results of step 5 and step 8 are carried into the following formula, and the virtual fault resistance R between the A-phase, B-phase and C-phase conducting cores and the metal shielding layer at the virtual fault point is estimated FAS (t,x)、R FBS (t,x)、R FCS (t,x)：
Further, in step 13, the value of the shift amount δ of each time window is determined by the following formula:
wherein f s Is the sampling frequency of the signal.
The beneficial effects achieved by the invention are as follows:
the method establishes an equivalent time domain model of the three-core cable after the fault occurs, and establishes fault phase identification, fault resistance estimation and fault accurate positioning criteria by measuring time domain signals of lead core current, ground voltage and ground wire current at the head and the tail ends of a line and utilizing a virtual fault point method. The method does not need phase-mode transformation and steady-state phasors, only extracts voltage and current signals within a period of time after the fault, can reliably identify the fault phase and estimate the fault resistance while realizing accurate fault positioning, and has higher engineering practice significance.
Drawings
Fig. 1 is a schematic flow chart of a fault locating method for a three-core cable in an embodiment of the invention.
Fig. 2 is a schematic diagram of a time domain equivalent model of a three-core cable after failure in an embodiment of the invention.
Detailed Description
The technical scheme of the invention is further described in detail below with reference to the attached drawings.
The technical scheme of the invention is described in detail with reference to the accompanying drawings. As shown in fig. 2, the three-core cable model after the fault occurs can be regarded as a lumped parameter circuit consisting of equivalent self-impedance and transimpedance of the a-phase, B-phase, C-phase conductive cores and the metal shielding layer. Wherein, L end is the line head end, R end is the line end, L is the line total length, x is the virtual fault distance. i.e LA 、i LB 、i LC And i LS The current signals respectively flow through the phase A, phase B and phase C conducting cores and the grounding wire at the head end of the circuit, u LA 、u LB 、u LC Ground voltage signals i of phase A, phase B and phase C conductors at the head end of the line RA 、i RB 、i RC Current signals respectively flowing through phase A, phase B and phase C conductors at the end of the line, u RA 、u RB 、u RC 、u S Ground voltage signals of A phase, B phase and C phase conducting cores and metal shielding layers at the tail end of the line respectively, R S Z is the resistance of the grounding wire AA 、Z AB 、Z AC 、Z AS The self impedance of the A phase guide core, the transimpedance of the A phase guide core and the B phase guide core, the transimpedance of the A phase guide core and the C phase guide core, the transimpedance of the A phase guide core and the metal shielding layer, Z BB 、Z BC 、Z BS Z is the self impedance of the B phase conducting core, the mutual impedance of the B phase conducting core and the C phase conducting core, and the mutual impedance of the B phase conducting core and the metal shielding layer respectively CC And Z CS Z is the self impedance of the C phase conducting core, the mutual impedance of the C phase conducting core and the metal shielding layer respectively LA 、Z LB 、Z LC For phase a, phase B and phase C equal payloads. According to circuit analysis, the three-core cable fault location method comprises the following specific steps.
And step 1, after the three-core cable fails, measuring the three-phase core current, the core-to-ground voltage and the ground wire current at the head end of the line, and the three-phase core current, the core-to-ground voltage and the shielding layer-to-ground voltage at the tail end of the line, so as to obtain the line impedance and the ground wire resistance parameters.
Step 2, intercepting an effective time window [ t ] for all acquired currents and voltages 1 ,t 2 ]A signal within; wherein t is 1 And t 2 The starting and ending moments of the effective time window are respectively determined according to the following formula:
wherein t is 0 The arrival time of the transient traveling wave head is the arrival time of the transient traveling wave head, and the value can be obtained by a wavelet mode maximum value method; t (T) t Representing the total length of the data window shift.
And 3, enabling the initial value of the distance x between the virtual fault point and the line head end to be 0.
Step 4, bringing the current and voltage signals measured by the head end of the line into the following steps to calculate the voltage signals u to ground of the phase A, the phase B and the phase C of the virtual fault point and the metal shielding layer LFAG (t,x)、 u LFBG (t,x)、u LFCG (t, x) and u LFSG (t,x)：
Wherein u is LA (t)、u LB (t)、u LC (t) and i LS (t) is the signal of the earth voltage and the earth wire current of the leading cores of the phase A, the phase B and the phase C of the line head end after the fault occurs, i LP (t) and i LS (t) is the current of the leading core of the P phase (P epsilon { A, B, C }) of the line head end after the fault occurs and the current signal of the grounding wire, R AP 、R BP 、R CP 、R SP The mutual resistances between the phase A, the phase B, the phase C and the metal shielding layer and the phase P conducting core are respectively R AS 、R BS 、R CS The mutual resistances between the phase A, phase B and phase C conducting cores and the metal shielding layer are respectively R SS Is the self-resistance of the metal shielding layer, R S L is the resistance of the grounding wire AP 、L BP 、L CP 、L SP Mutual inductance between phase A, phase B, phase C and metal shielding layer and phase P, L AS 、L BS 、L CS Mutual inductance between the phase A, phase B and phase C conductive cores and the metal shielding layer, L SS Is the self inductance of the metal shielding layer.
Step 5, bringing the result of the step 4 into the following formula, and calculating voltage signals between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point:
wherein u is LFAS (t,x)、u LFBS (t,x)、u LFCS (t, x) are virtual faults calculated by using the current and voltage signals measured by the line head end respectivelyAnd voltage signals between the phase A, phase B and phase C conducting cores and the metal shielding layer at the barrier point.
Step 6, the current and voltage signals measured at the tail end of the line are brought into the following steps to calculate the voltage signals u to the ground of the phase A, the phase B and the phase C of the conducting core and the metal shielding layer at the virtual fault point RFAG (t,x)、 u RFBG (t,x)、u RFCG (t, x) and u RFSG (t,x)：
Wherein u is RA (t)、u RB (t)、u RC (t) and u S (t) the voltages of the conducting cores of the phase A, the phase B and the phase C at the tail end of the line and the metal shielding layer after the fault occurs are respectively the voltages of the conducting cores of the phase A, the phase B and the phase C and the voltages of the metal shielding layer and i RP And (t) is the P-phase (P epsilon { A, B, C }) pilot core current at the tail end of the line after the fault occurs, and l is the total length of the line.
Step 7, the result of the step 6 is brought into the following formula, and voltage signals between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point are calculated:
wherein u is RFAS (t,x)、u RFBS (t,x)、u RFCS (t, x) are voltage signals between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point calculated by using the current and voltage signals measured by the line end.
Step 8, calculating the current signal i of the phase A, the phase B and the phase C flowing to the metal shielding layer at the virtual fault point x according to the following formula FAS (t,x)、i FBS (t,x)、i FCS (t,x)：
Wherein i is LA (t)、i LB (t)、i LC (t) is phase A measured at the head end of the line,B-phase and C-phase conducting core current, i RA (t)、i RB (t)、i RC (t) A, B, C phase conductor currents measured at the end of the line, respectively.
Step 9, the calculation results of the step 5 and the step 8 are carried into the following formula, and the virtual fault resistance R between the A phase, the B phase, the C phase conducting core and the metal shielding layer at the virtual fault point is estimated FAS (t, x)、R FBS (t,x)、R FCS (t,x)：
Step 10, the calculation results of the step 5 and the step 7 are carried into the following formula, and absolute differences of voltages between the phase A, phase B, phase C conducting cores and the metal shielding layer at the virtual fault point are calculated in an effective time window [ t ] 1 ,t 2 ]Integral D in A (x)、D B (x)、D C (x)：
Step 11, if the virtual fault distance x is less than or equal to the total length l of the line, let x=x+1m, and repeatedly execute steps 4 to 10; otherwise, the following vectors are obtained:
wherein R is FPS (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the virtual fault resistance vector between the P (P epsilon { A, B, C }) phase conducting core and the metal shielding layer, D P (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the absolute difference of the voltages between the P-phase conducting core and the metal shielding layer is the integral vector, N x Function F for the total number of virtual fault points set on the line z () For taking the integer part of a real number.
Step 12, determining the vector R according to the result of step 11 FPS (t 2 ) Average value of (D) and vector D P (t 2 ) Is respectively denoted as R FPS_mean (t 2 ) And D P_min (t 2 )。
Step 13, if the expiration time t of the effective time window 2 Less than or equal to the effective time window starting time t 1 Total length of shift T of data window t And, let t 1 ＝t 1 +δ，t 2 ＝t 2 +δ (δ represents the shift amount per time window, the value of which is the inverse of the sampling frequency, i.e., the sampling interval), steps 3 to 12 are repeatedly performed; otherwise, the following vectors are obtained:
wherein R is FPS Represents the virtual fault resistance average vector, D, between the P (P epsilon { A, B, C }) phase conductor and the metallic shielding layer at different effective time window termination times and virtual fault distances P An integral minimum vector, N, of absolute difference values of voltages between the P-phase conducting core and the metal shielding layer in the effective time window under different effective time window ending moments and virtual fault distances t Step 13 is performed for the total number of different set valid time window expiration moments.
Step 14, determining the vector R according to the result of step 13 FPS Average value of (1) is denoted as R FPS_mean ；
And 15, identifying a fault phase by using the following criteria, and estimating fault resistance:
wherein the function min () is used for the determined R FAS_mean 、R FBS_mean And R is FCS_mean The minimum of the three numbers and the corresponding index (A, B, C),
Step (a)16, calculating the actual fault accurate distance x by using the following method F ：
Wherein k is a continuous variable and k ε Z + 。
In order to verify the correctness of the method, a 10kV single-end radiation type three-core cable distribution network fault simulation model is built on PSCAD. The three-core cable adopts a frequency-dependent characteristic phase model. The total length of the outgoing cables 1, 2 and 3 is respectively as follows: 1.5km, 2km and 1km. Faults were simulated on a third cable for different conditions and the fault location results obtained are shown in table 1. From the table it can be seen that: the method can identify fault resistance and realize accurate fault positioning of the three-core cable under different fault conditions, and the maximum and minimum positioning errors are 25m and 2m respectively.
TABLE 1 three-core Cable fault location results under different conditions
/>
The above description is merely of preferred embodiments of the present invention, and the scope of the present invention is not limited to the above embodiments, but all equivalent modifications or variations according to the present disclosure will be within the scope of the claims.
Claims (6)
1. A three-core cable fault positioning method based on time domain analysis is characterized in that: the method comprises the following steps:
step 1, after a three-core cable fails, measuring three-phase core current, core-to-ground voltage and ground wire current at the head end of a line, and three-phase core current, core-to-ground voltage and shield layer-to-ground voltage at the tail end of the line, so as to obtain line impedance and ground wire resistance;
step 2, intercepting an effective time window [ t ] for all acquired currents and voltages 1 ,t 2 ]A signal within; wherein t is 1 And t 2 The starting time and the ending time of the effective time window are respectively;
step 3, enabling the initial value of the distance x between the virtual fault point and the line head end to be 0;
step 4, bringing the current and voltage signals measured by the head end of the line into the following steps to calculate the voltage signals u to ground of the phase A, the phase B and the phase C of the virtual fault point and the metal shielding layer LFAG (t,x)、u LFBG (t,x)、u LFCG (t, x) and u LFSG (t,x)：
Wherein u is LA (t)、u LB (t)、u LC (t) and i LS (t) is the signal of the earth voltage and the earth wire current of the leading cores of the phase A, the phase B and the phase C of the line head end after the fault occurs, i LP (t) and i LS (t) is the current of the P-phase conducting core at the head end of the line after the fault and the current signal of the grounding wire, P is { A, B, C }, R AP 、R BP 、R CP 、R SP The mutual resistances between the phase A, the phase B, the phase C and the metal shielding layer and the phase P conducting core are respectively R AS 、R BS 、R CS The mutual resistances between the phase A, phase B and phase C conducting cores and the metal shielding layer are respectively R SS Is the self-resistance of the metal shielding layer, R S L is the resistance of the grounding wire AP 、L BP 、L CP 、L SP Mutual inductance between phase A, phase B, phase C and metal shielding layer and phase P, L AS 、L BS 、L CS Respectively A phase, B phase and C phase guide coresMutual inductance with metal shielding layer, L SS Is the self inductance of the metal shielding layer;
step 5, according to u LFAG (t,x)、u LFBG (t,x)、u LFCG (t, x) and u LFSG (t, x) calculating the voltage signals u between the A-phase, B-phase, C-phase conductive cores and the metallic shielding layer at the virtual fault point LFAS (t,x)、u LFBS (t,x)、u LFCS (t,x)；
Step 6, the current and voltage signals measured at the tail end of the line are brought into the following steps to calculate the voltage signals u to the ground of the phase A, the phase B and the phase C of the conducting core and the metal shielding layer at the virtual fault point RFAG (t,x)、u RFBG (t,x)、u RFCG (t, x) and u RFSG (t,x)：
Wherein u is RA (t)、u RB (t)、u RC (t) and u S (t) the voltages of the conducting cores of the phase A, the phase B and the phase C at the tail end of the line and the metal shielding layer after the fault occurs are respectively the voltages of the conducting cores of the phase A, the phase B and the phase C and the voltages of the metal shielding layer and i RP (t) P-phase conductor current at the tail end of the line after the fault occurs, and l is the total length of the line;
step 7, according to u RFAG (t,x)、u RFBG (t,x)、u RFCG (t, x) and u RFSG (t, x) calculating the voltage signals u between the A-phase, B-phase, C-phase conductive cores and the metallic shielding layer at the virtual fault point RFAS (t,x)、u RFBS (t,x)、u RFCS (t,x)；
Step 8, calculating the current signal i of the phase A, the phase B and the phase C flowing to the metal shielding layer at the virtual fault point x according to the following formula FAS (t,x)、i FBS (t,x)、i FCS (t,x)：
Step 9, according to the voltage signal u LFAS (t,x)、u LFBS (t,x)、u LFCS (t, x) and current senseNumber i FAS (t,x)、i FBS (t,x)、i FCS (t, x) calculating virtual fault resistance R between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point FAS (t,x)、R FBS (t,x)、R FCS (t,x)；
Step 10, the calculation results of the step 5 and the step 7 are carried into the following formula, and absolute differences of voltages between the phase A, phase B, phase C conducting cores and the metal shielding layer at the virtual fault point are calculated in an effective time window [ t ] 1 ,t 2 ]Integral D in A (x)、D B (x)、D C (x)：
Step 11, if the virtual fault distance x is less than or equal to the total length l of the line, let x=x+1m, and repeatedly execute steps 4 to 10; otherwise, the following vectors are obtained:
wherein R is FPS (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the virtual fault resistance vector between the P-phase conducting core and the metal shielding layer, D P (t 2 ) Indicating that the effective time window is terminated at time t 2 At different virtual fault distances, the absolute difference of the voltages between the P-phase conducting core and the metal shielding layer is the integral vector, N x Function F for the total number of virtual fault points set on the line z () For taking an integer part of a real number;
step 12, determining the vector R according to the result of step 11 FPS (t 2 ) Average value of (D) and vector D P (t 2 ) Is respectively denoted as R FPS_mean (t 2 ) And D P_min (t 2 )；
Step 13, if the expiration time t of the effective time window 2 Less than or equal to the effective time window starting time t 1 Total length of shift T of data window t And, let t 1 ＝t 1 +δ，t 2 ＝t 2 +δ, δ represents the amount of shift per time window, repeatedly performing steps 3 to 12; otherwise, the following vectors are obtained:
wherein R is FPS Represents a virtual fault resistance average vector, D, between the P-phase conducting core and the metal shielding layer at different effective time window ending moments and virtual fault distances P An integral minimum vector, N, of absolute difference values of voltages between the P-phase conducting core and the metal shielding layer in the effective time window under different effective time window ending moments and virtual fault distances t The total number of the set different effective time window ending moments;
step 14, determining the vector R according to the result of step 13 FPS Average value of (1) is denoted as R FPS_mean ；
And 15, identifying a fault phase by using the following criteria, and estimating fault resistance:
wherein the function min () is used for the determined R FAS_mean 、R FBS_mean And R is FCS_mean The minimum of the three numbers and the corresponding index (A, B, C);
step 16, calculating the actual fault accurate distance x by using the following method F ：
Wherein k is a continuous variable and k ε Z + 。
2. The three-core cable fault location method based on time domain analysis of claim 1, wherein: in step 2 and step 13, the start-stop time of the effective time window and the total length of the data window shift are determined according to the following formula:
wherein t is 0 The arrival time of the traveling wave head can be obtained by a wavelet mode maximum value method; t (T) t The total length is shifted for the data window.
3. The three-core cable fault location method based on time domain analysis of claim 1, wherein: in step 5, the result of step 4 is brought into the following formula, and voltage signals between the a-phase, B-phase and C-phase conducting cores and the metal shielding layer at the virtual fault point are calculated:
wherein u is LFAS (t,x)、u LFBS (t,x)、u LFCS And (t, x) are voltage signals between the phase A, phase B and phase C conducting cores and the metal shielding layer at the virtual fault point obtained by calculation by using the current and voltage signals measured by the head end of the line.
4. The three-core cable fault location method based on time domain analysis of claim 1, wherein: in step 7, the result of step 6 is brought into the following formula, and voltage signals between the a-phase, B-phase and C-phase conducting cores and the metal shielding layer at the virtual fault point are calculated:
wherein u is RFAS (t,x)、u RFBS (t,x)、u RFCS (t, x) are voltage signals between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point calculated by using the current and voltage signals measured by the line end.
5. The three-core cable fault location method based on time domain analysis of claim 1, wherein: in step 9, the calculation results of step 5 and step 8 are carried into the following formula, and the virtual fault resistance R between the A phase, B phase and C phase conducting cores and the metal shielding layer at the virtual fault point is estimated FAS (t,x)、R FBS (t,x)、R FCS (t,x)：
6. The three-core cable fault location method based on time domain analysis of claim 1, wherein: in step 13, the value of the shift amount δ for each time window is determined by the following equation:
wherein f s Is the sampling frequency of the signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210414945.2A CN115184718B (en) | 2022-04-20 | 2022-04-20 | Three-core cable fault positioning method based on time domain analysis |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210414945.2A CN115184718B (en) | 2022-04-20 | 2022-04-20 | Three-core cable fault positioning method based on time domain analysis |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115184718A CN115184718A (en) | 2022-10-14 |
| CN115184718B true CN115184718B (en) | 2023-11-14 |
Family
ID=83512176
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210414945.2A Active CN115184718B (en) | 2022-04-20 | 2022-04-20 | Three-core cable fault positioning method based on time domain analysis |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115184718B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117092453B (en) * | 2023-10-19 | 2023-12-19 | 华南理工大学 | Fault positioning method, device and equipment for three-core cable and storage medium |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997034160A1 (en) * | 1996-03-11 | 1997-09-18 | Electric Power Research Institute, Inc. | Locating a fault in an electrical power cable |
| JP2011017637A (en) * | 2009-07-09 | 2011-01-27 | Kansai Electric Power Co Inc:The | Method and device for detecting ground fault position of cable |
| CN106443329A (en) * | 2016-09-07 | 2017-02-22 | 南京南瑞继保电气有限公司 | System and method for detecting fault of DC grounding electrode line |
| CN106443351A (en) * | 2016-11-02 | 2017-02-22 | 南京工程学院 | System and method for detecting faults of multi-core cables of ships |
| CN108693446A (en) * | 2018-05-25 | 2018-10-23 | 中国矿业大学 | A kind of Fault Locating Method of non-synchronous sampling power grid transient state travelling wave modulus time difference |
| CN112083271A (en) * | 2020-08-18 | 2020-12-15 | 昆明理工大学 | 10kV cable online distance measurement method based on sheath current traveling wave time-frequency composite analysis |
| CN113093050A (en) * | 2021-03-31 | 2021-07-09 | 中国矿业大学 | Cable early fault identification method and system based on cable grounding wire current time-frequency characteristics |
| CN113655342A (en) * | 2021-09-23 | 2021-11-16 | 国网江苏省电力有限公司连云港供电分公司 | Three-core cable single-phase fault positioning method based on multi-conductor coupling model |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3171185B1 (en) * | 2015-11-20 | 2018-06-27 | Siemens Aktiengesellschaft | Method and device for determining the fault location in the event of a fault on an electric line |
| KR102180748B1 (en) * | 2019-08-21 | 2020-11-19 | 연세대학교 산학협력단 | Multi-core cable fault classification system and method |
-
2022
- 2022-04-20 CN CN202210414945.2A patent/CN115184718B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997034160A1 (en) * | 1996-03-11 | 1997-09-18 | Electric Power Research Institute, Inc. | Locating a fault in an electrical power cable |
| JP2011017637A (en) * | 2009-07-09 | 2011-01-27 | Kansai Electric Power Co Inc:The | Method and device for detecting ground fault position of cable |
| CN106443329A (en) * | 2016-09-07 | 2017-02-22 | 南京南瑞继保电气有限公司 | System and method for detecting fault of DC grounding electrode line |
| CN106443351A (en) * | 2016-11-02 | 2017-02-22 | 南京工程学院 | System and method for detecting faults of multi-core cables of ships |
| CN108693446A (en) * | 2018-05-25 | 2018-10-23 | 中国矿业大学 | A kind of Fault Locating Method of non-synchronous sampling power grid transient state travelling wave modulus time difference |
| CN112083271A (en) * | 2020-08-18 | 2020-12-15 | 昆明理工大学 | 10kV cable online distance measurement method based on sheath current traveling wave time-frequency composite analysis |
| CN113093050A (en) * | 2021-03-31 | 2021-07-09 | 中国矿业大学 | Cable early fault identification method and system based on cable grounding wire current time-frequency characteristics |
| CN113655342A (en) * | 2021-09-23 | 2021-11-16 | 国网江苏省电力有限公司连云港供电分公司 | Three-core cable single-phase fault positioning method based on multi-conductor coupling model |
Non-Patent Citations (11)
| Title |
|---|
| Comparison of Location Accuracy between Frequency Domain Reflectometry and Line Resonance Analysis for Power Cables;Lu Chen等;2020 IEEE International Conference on High Voltage Engineering and Application (ICHVE);全文 * |
| Permanent Fault Location for Three-Core Cable Using Multiconductor Coupling Model;Zehua Tang等;IEEE Transactions on Power Delivery;全文 * |
| 噪声时域反射法实现多根电缆故障的同时检测;马培国等;激光与光电子学进展;全文 * |
| 基于TDR多芯信号电缆故障测试装置的研制;吕瀚;吴雄伟;关伟智;吴林斌;;大地测量与地球动力学(S1);全文 * |
| 基于双层阻抗模型的三相单芯电缆自恢复故障定位;张姝;林圣;唐进;何正友;;电工技术学报(17);全文 * |
| 基于多源暂稳态信息的电缆型配电网故障辨识与定位研究;彭楠;中国博士学位论文全文数据库工程科技Ⅱ辑;全文 * |
| 基于时域反射的多芯线缆检测装置设计;汪兴海;计算机与数字工程;全文 * |
| 基于暂态特征模量分析的 配网三芯铠装电缆故障感知与测距;彭楠等;中国电机工程学报;全文 * |
| 矿山电网电弧性接地故障区段定位与辨识研究;程成;中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑;全文 * |
| 考虑金属护套和铠装结构的电缆故障测距方法;宋勤;王媛媛;;电气技术(10);全文 * |
| 计及金属护层结构的电缆单端故障测距方法;唐进;张姝;林圣;何正友;;中国电机工程学报(06);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115184718A (en) | 2022-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Suonan et al. | A novel fault-location method for HVDC transmission lines | |
| CN103792465B (en) | A kind of method of the range finding of the one-phase earthing failure in electric distribution network based on residual voltage | |
| Christoforidis et al. | A hybrid method for calculating the inductive interference caused by faulted power lines to nearby buried pipelines | |
| CN110082636B (en) | Power cable fault positioning method and system | |
| CN103941147B (en) | Utilize the distribution network cable single-phase ground fault distance measuring method of transient state principal frequency component | |
| CN102135571B (en) | Anti-interference measurement method for zero sequence impedance of super-high-voltage/ultrahigh-voltage multi-loop power transmission line | |
| CN109633367B (en) | Power transmission line fault positioning method based on voltage and current changes before and after fault | |
| CN111308264B (en) | Power distribution network single-phase earth fault section positioning method based on cosine similarity | |
| Qi et al. | Calculation of interference voltage on the nearby underground metal pipeline due to the grounding fault on overhead transmission lines | |
| CN109100605B (en) | Single-end positioning method for high-voltage cable single-phase earth fault by utilizing fault boundary condition | |
| Zhang et al. | A new fault-location algorithm for extra-high-voltage mixed lines based on phase characteristics of the hyperbolic tangent function | |
| CN111638423B (en) | Positioning method for ground faults of power cable sheath layer and armor layer | |
| CN115184718B (en) | Three-core cable fault positioning method based on time domain analysis | |
| CN113655342A (en) | Three-core cable single-phase fault positioning method based on multi-conductor coupling model | |
| Cao et al. | Asynchronous fault location scheme based on voltage distribution for three-terminal transmission lines | |
| Zhang et al. | Voltage-sag-profiles-based fault location in high-speed railway distribution system | |
| Qin et al. | A novel pilot protection scheme for HVDC lines based on waveform matching | |
| CN103424627B (en) | The method of double-end measurement parallel grid line zero-sequence impedance | |
| Zhang et al. | Fault location method for three-core cable using amplitude ratio of shield-grounding wire currents | |
| CN112904233B (en) | Ground fault positioning method and device based on ground wire current reactive component | |
| CN114859168A (en) | Three-core cable fault location method based on double-end asynchronous measurement | |
| CN113805012B (en) | Power distribution network fault section identification method suitable for neutral point through small-resistance grounding cable | |
| Guo et al. | A method of 20 kV cable line fault location based on sheath grounding current | |
| CN103424628A (en) | Method for measuring parallel grid line positive sequence impedance | |
| CN107064728B (en) | The single-ended holographic frequency domain Fault Locating Method of ultra-high-tension power transmission line |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |