CN110703041A - Power transmission line fault detection method based on current-current derivative two-dimensional space - Google Patents

Power transmission line fault detection method based on current-current derivative two-dimensional space Download PDF

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CN110703041A
CN110703041A CN201911015324.1A CN201911015324A CN110703041A CN 110703041 A CN110703041 A CN 110703041A CN 201911015324 A CN201911015324 A CN 201911015324A CN 110703041 A CN110703041 A CN 110703041A
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CN110703041B (en
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童晓阳
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Southwest Jiaotong University
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    • 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
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • 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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Abstract

The invention discloses a power transmission line fault detection method based on a current-current derivative two-dimensional space. Collecting currents on two sides of a power transmission line, starting fault detection according to conventional sudden change current, calculating current derivatives at each moment of a quarter period after the original sudden change moment, counting the number of the current derivatives which are more than 0 or less than 0, determining the quadrant of the current derivatives in the current-current derivative two-dimensional space in the period of time on two sides of the line, and checking and determining the real sudden change moment t1And the quarter period true end time t2For t1To t2And calculating the current derivative at each moment to obtain the quadrant satisfaction rates of the two sides, and accurately judging the quadrant of the current derivative in the 1 st quarter period after the current at the two sides mutates, so as to detect the line fault condition. The invention can accurately detect line faults under various fault situations, is not influenced by transition resistance, has low requirement on the synchronism of currents on two sides and has stronger anti-asynchronism capability.

Description

Power transmission line fault detection method based on current-current derivative two-dimensional space
Technical Field
The invention relates to the technical field of fault detection of power grid transmission lines.
Background
At present, most protection algorithms adopt a Fourier algorithm, current protection is carried out by adopting signals of various phases of current, and the signals can participate in the calculation of a directional element, but the current protection is easily influenced by a transition resistor, and the directional element has a certain dead zone and is influenced by the synchronization of signals at two sides.
Aiming at the defects of the existing current protection algorithm, the invention provides a power transmission line fault detection method based on a current-current derivative two-dimensional space. The method has the advantages that by utilizing the sampling values of the currents of the phases on the two sides of the line, the fault line can be accurately detected in about 1/4 cycles after the fault occurs, the calculated amount is small, the method is not influenced by transition resistance, and the method has better tolerance to the asynchronous signals on the two sides.
Disclosure of Invention
The invention aims to provide a power transmission line fault detection method based on a current-current derivative two-dimensional space, which can effectively solve the problem of power transmission line fault detection under the conditions of high-resistance grounding fault, information asynchronization and the like.
The purpose of the invention is realized by the following technical scheme: a power transmission line fault detection method based on a current-current derivative two-dimensional space comprises the following steps:
step one, setting current sampling points in two substations on two sides of a power transmission line to be detected for faults, respectively sampling line currents on two sides of the power transmission line, extracting three-phase current signals of each sampling moment and two cycles before the sampling moment, and calculating each phase current abrupt change delta i at each momentk＝||ik-ik-N|-|ik-N-ik-2NWhere N is the number of samples in a sampling period T, ikIs the current sample value at the k-th instant, ik-NIs the current sample value at the k-N time, ik-2NIs the current sampling value at the k-2N moment; according to the conventional current mutation starting criterion, if the current mutation on one side is larger than the threshold value, starting the subsequent fault detection, and recording the moment as the original mutation moment t0The fault detection goes to the next step, otherwise, the fault detection goes back to
Step one;
step two, extracting the phase with the largest three-phase current mutation quantity on two sides of the power transmission line from the original mutation time t0To t0+1/4 period, calculating the current derivative of each phase, and recording the current derivative i of k timeDkI.e. iDk＝(ik-ik-1) A,/Δ t, wherein ik、ik-1Current sampling values at the kth moment and the kth-1 moment respectively, wherein delta t is the time difference between two adjacent sampling moments;
step three, aiming at the original mutation moment t at one side of the power transmission line0To
Figure BDA0002245516130000011
The current derivative at each moment is checked to see if it is greater than 0, and if it is greater than 0, 1 count is made; when the statistics are finished, if the total count is larger than
Figure BDA0002245516130000012
The original mutation time t of the side is preliminarily judged0To
Figure BDA0002245516130000013
Is located in quadrant 1 of the two-dimensional space of the current-current derivative, and is marked as that the current derivative of the 1 st 1/4 cycle on the side is located in quadrant 1;
otherwise, for the original mutation moment t of the side of the power transmission line0To
Figure BDA0002245516130000014
Checking the current derivative at each moment in turn whether the current derivative is less than 0, and counting for 1 time if the current derivative is less than 0; when the statistics are finished, if the total count is larger than
Figure BDA0002245516130000015
The original mutation time t of the side is preliminarily judged0To
Figure BDA0002245516130000021
Is located in quadrant 3 of the two-dimensional space of the current-current derivative, and is marked as that the current derivative of the 1 st 1/4 cycle on the side is located in quadrant 3;
in the same way, processing the current derivative of the other side of the transmission line, and preliminarily judging the quadrant of the current derivative of the 1 st 1/4 period on the side in the two-dimensional space of the current-current derivative;
step four, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, the original mutation moment t from the side0Initially, the current at each moment and two successive moments thereafter is checked in sequenceIf the derivatives are all larger than 0 at the same time, if the condition is satisfied, the time is defined as the real mutation time t of the side1And stopping the inspection;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is positioned in the 3 rd quadrant, the original sudden change time t from the side0Firstly, checking whether the current derivative of each time and two continuous time after each time is less than 0 at the same time in sequence, and if the condition is met, defining the time as the real sudden change time t of the side1And stopping the inspection;
in the same way, the original mutation time t at the other side of the transmission line is processed0To
Figure BDA0002245516130000022
Finding the true abrupt change time t of the side1(ii) a This eliminates the original mutation time t0After t0And t1The current derivative of the random disturbance present in between;
step five, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, aiming at the side from the real mutation moment t1ToIs greater than 0, and the current derivatives of 3 consecutive moments thereafter are all less than 0 at the same time, and if this condition is met, the moment is defined as the true sudden change moment t of the side1True end t of the last 1 st 1/4 th cycle2And stopping the inspection;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is positioned in the 3 rd quadrant, the current derivative is positioned from the real sudden change time t on the side1To
Figure BDA0002245516130000024
The current derivative of each time is checked whether the current derivative of each time is less than 0, and the current derivatives of 3 subsequent times are all greater than 0 at the same time, if the condition is met, the time is defined as the real sudden change time t of the side1True end t of the last 1 st 1/4 th cycle2And stopping the inspection;
in the same way, the current derivative of the other side of the transmission line is processed to find the real end time t of the 1 st 1/4 cycle of the side2(ii) a This eliminates the actual mutation time t1Then the derivative of the current which fluctuates around the 1 st 1/4 th period is found, and the real end time t of the 1 st 1/4 th periods on both sides is found2；
Step six, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, the current derivative on the side is subjected to real sudden change from the time t1To the real end of the 1 st 1/4 th cycle2The current derivative at each moment is checked whether it is greater than 0, and if it is greater than 0, the total count C is increased by 1; when the statistics are finished, dividing C by t1To t2The number Num of the sampling points (i.e. Num ═ t)2-t1) And/delta T, obtaining a quadrant satisfaction rate F, namely F is T/Num 100, and if the quadrant satisfaction rate F is greater than a threshold value 90, accurately judging the real mutation time T of the side1The derivative of the current for the second 1 st 1/4 th cycle is in quadrant 1;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is in quadrant 3, then the t is determined for the side1To t2Respectively checking whether it is less than 0, and if it is less than 0, adding 1 to the total count C; when the statistics are finished, dividing C by t1To t2The number Num of the sampling points (i.e. Num ═ t)2-t1) And/delta t, obtaining a quadrant satisfaction rate F, namely F is C/Num 100, and if the quadrant satisfaction rate F is greater than a threshold value 90, accurately judging the real mutation time t of the side1The derivative of the current for the last 1 st 1/4 th cycle is in quadrant 3;
in the same way, the current derivative of the other side of the power transmission line is processed, and the real mutation moment t of the side is accurately judged1The quadrant in which the current derivative of the last 1 st 1/4 cycles resides;
seventhly, transmitting the quadrant where the current derivative of the 1 st 1/4 th cycle is located to a protection device of the opposite side through an optical fiber channel or a wide area communication network on two sides of the power transmission line; establishing line fault detection criterion if the transmission lineReal sudden change time t on both sides1Judging that the line has a fault if the current derivatives of the last 1 st 1/4 th period are all located in the 1 st quadrant;
if the real sudden change moment t of one side of the transmission line1The derivative of the current in the second 1 st 1/4 th cycle is in quadrant 1, while the other side really changes abruptly at time t1And if the current derivative of the last 1 st 1/4 th period is in the 3 rd quadrant, judging the line to be normal, and returning to the step one.
Compared with the prior art, the invention has the advantages and effects that:
1) the method provided by the invention can quickly and accurately detect the fault line without being influenced by the transition resistance;
2) the method provided by the invention can dynamically capture the real mutation moment t1And the current derivative in the 1 st quadrant or the 3 rd quadrant of the two-dimensional space of the current-current derivative in the 1 st 1/4 th period is used for judging the fault condition of the line, and the calculation amount is small.
3) The method provided by the invention utilizes current signals at two sides to respectively obtain real mutation time t1And the true end time t of the 1 st 1/4 th cycle2Then obtaining the real mutation time t on both sides1The current derivative of the last 1 st 1/4 th period is in a quadrant of a current-current derivative two-dimensional space, so that the fault condition of the line is judged, and the real mutation time t of each of two sides of the line is used1On the basis, the out-of-sync of the current on both sides of the line has little effect on fault detection. Therefore, the method has stronger capacity of resisting asynchronous.
Drawings
FIG. 1 is a flow chart of the present invention
FIG. 2 is a schematic diagram of an IEEE39 node test system according to the present invention
FIG. 3 is a graph of the raw current-current derivative for the 1 st cycle on side 4 of lines L4-14 in the event of a metallic ground fault on lines L4-14 in accordance with the present invention
FIG. 4 is a graph of the raw current-current derivative for the 1 st cycle on side 14 of lines L4-14 in the event of a metallic ground fault on lines L4-14 in accordance with the present invention
FIG. 5 is a graph of the current-current derivative after the true break time of the 1 st cycle on side 4 of the line L4-14 when a metallic ground fault occurs on the line L4-14 in accordance with the present invention
FIG. 6 is a graph of the current-current derivative after the true break time of the 1 st cycle on side 14 of line L4-14 when a metallic ground fault occurs in line L4-14 in accordance with the present invention
FIG. 7 is a graph of the raw current-current derivative for the 1 st cycle on side 3 of line L3-4 in the event of a metallic ground fault on line L4-14 in accordance with the present invention
FIG. 8 is a graph of the raw current-current derivative for the 1 st cycle on side 4 of line L3-4 in the event of a metallic ground fault on line L4-14 in accordance with the present invention
FIG. 9 is a graph of the raw current-current derivative for the 1 st cycle on side 4 of lines L4-14 under a high impedance ground fault of lines L4-14 in accordance with the present invention
FIG. 10 is a graph of the raw current-current derivative for the 14 th cycle of line L4-14 under a high impedance ground fault of line L4-14 in accordance with the present invention
FIG. 11 is a graph of the raw current-current derivative for the 1 st cycle on side 3 of line L3-4 under a high impedance ground fault of line L4-14 in accordance with the present invention
FIG. 12 is a graph of the raw current-current derivative for the 1 st cycle on the 4 th side of line L3-4 under a high impedance ground fault of line L4-14 in accordance with the present invention
Detailed Description
The technical contents of the invention are described in detail below with reference to the accompanying drawings and specific embodiments:
FIG. 1 is a flowchart of a method for detecting a fault in a power transmission line based on a two-dimensional space of current-current derivatives according to an embodiment of the present invention
An IEEE39 node system is built by utilizing electromagnetic transient simulation software PSCAD/EMTDC, and the structure diagram of the system is shown in figure 2. In fig. 2, the G with the ring represents a generator, the serial numbers 1-39 are serial numbers of all buses, the system voltage level is 345kV, the frequency is 50Hz, the sampling frequency is 10kHz, and the time difference between two adjacent sampling moments is 0.0001 s. Setting faults in an IEEE39 node system, extracting corresponding fault data, and programming in an MATLAB to realize the fault detection method.
In the IEEE39 node system, the worst position of the lines L4-14, namely the tail end of the lines, namely the position 95% away from the head end is set, and the metallic grounding fault and the 300 omega high-resistance fault occur at 0.6s respectively so as to verify the accuracy and the capability of resisting the transition resistance of the method.
Case 1 metallic ground fault occurred when 95% of the lines L4-14 were at 0.6s
The current, the current derivative, from 0.6s to 1/2 cycles across the faulted line L4-14 is shown in table 1.
TABLE 1 Current, Current derivatives from 0.6s to 1/2 cycles on both sides in the event of a metallic ground fault in line L4-14
Figure BDA0002245516130000041
Figure BDA0002245516130000051
Figure BDA0002245516130000061
As can be seen from the parameters in Table 1, according to step 1 of the present invention, the original mutation time t on the 4-side of line L4-14 is obtained00.6002s, original mutation time t on side 1400.6001 s;
according to the steps 2, 3 and 4, the real mutation time t of the 4 side of the line L4-14 is obtained10.6007s, true mutation time t on side 1410.6002 s;
according to step 5, the real mutation time t on the 4-side of the line L4-14 is obtained1Real end time t of the last 1 st 1/4 th cycle20.6077s, true mutation time t on side 141Real end time t of the last 1 st 1/4 th cycle2For 0.6076s, two sides t can be seen1To t2In theory, 1/4 cycles are 0.005s, and in practice 0.6077-0.6007-0.0076 s and 0.6076-0.6002-0.0074 s, respectively.
The line L4-14 is metallically connectedThe original current-current derivative curves of the 1 st cycle on either side 4 or side 14 of line L4-14 at ground fault are shown in fig. 3 and 4. I in FIG. 3dRepresenting the current derivative, i represents the current.
As can be seen from FIG. 3, the 1 st 1/4 cycle on side 4 of line L4-14 is in quadrant 1, but from the original snap-through time t0To the actual mutation moment t1With 5 random disturbances in between, detects a true sudden change time t on the 4-side of the line L4-141Is 0.6007 s. Similarly, the 14 side slave t of the line L4-14 is found from FIG. 40To t1With the current derivative of 1 random disturbance in between.
The current-current derivative curves after the actual abrupt change time of the 1 st cycle on the 4 side or the 14 side of the line L4-14 when the line L4-14 has a metallic ground fault are shown in FIGS. 5 and 6, with t removed0And t1The current derivative of the random disturbance present in between.
According to the step 6, calculating to obtain a quadrant satisfaction rate F of the 4 side of the line L4-14, which is 100 and is greater than the threshold 90, and determining that the current derivative of the 1 st 1/4 cycle after the 4 side current of the line L4-14 suddenly changes is located in the 1 st quadrant of the current-current derivative two-dimensional space; and calculating to obtain a quadrant satisfaction rate F of the 14 side, which is 100 and is larger than a threshold value 90, and determining that the current derivative of the 1 st 1/4 th period after the current on the 14 side is suddenly changed is located in the 1 st quadrant of the two-dimensional space of the current-current derivative.
And (4) judging the fault of the line L4-14 according to the line fault detection criterion in the step (7), wherein the detection result is correct.
When the line L4-14 has a metallic ground fault, the current and the derivative of the current are shown in Table 2 from 0.6s to 1/2 cycles on both sides of the normal line L3-4.
TABLE 2 metallic ground fault in line L4-14, the current derivative from 0.6s to 1/2 cycles on both sides of the normal line L3-4
Figure BDA0002245516130000071
Figure BDA0002245516130000081
Figure BDA0002245516130000091
As can be seen from the parameters in Table 2, according to step 1 of the present invention, the original mutation time t on the 3-side of line L3-4 is obtained00.6001s, original mutation time t on side 400.6002 s;
according to step 4, the true mutation time t on the 3 side of the line L3-4 is obtained10.6006s, true mutation time t on side 410.6004 s;
according to step 5, the true mutation time t on the 3 side of the line L3-4 is obtained1Real end time t of the last 1 st 1/4 th cycle20.6078s, true mutation time t on side 41Real end time t of the last 1 st 1/4 th cycle20.6079s, two sides t can be seen from Table 21To t2In theory, 1/4 cycles are 0.005s, and in practice 0.6078-0.6006-0.0072 s and 0.6076-0.6004-0.0072 s, respectively.
The original current-current derivative curves for the 1 st cycle on either side 3 or side 4 of line L3-4 are shown in FIGS. 7 and 8 when a metallic ground fault occurs on line L4-14.
According to the step 6, calculating to obtain a quadrant satisfaction rate F of the 3 side of the line L3-4, which is 100 and is greater than a threshold value 90, and determining that the current derivative of the 1 st 1/4 cycle after the current of the 3 side is suddenly changed is located in the 3 rd quadrant of the current-current derivative two-dimensional space; and calculating to obtain a quadrant satisfaction rate F of the 4 side, wherein the quadrant satisfaction rate F is 100 and is larger than a threshold value 90, and determining that the current derivative of the 1 st 1/4 th period after the 4 side current mutation is located in the 1 st quadrant of the current-current derivative two-dimensional space.
Since the current derivatives of the 1 st 1/4 cycle after the current on the two sides of the line L3-4 suddenly changes are respectively located in the 1 st quadrant and the 3 rd quadrant of the current-current derivative two-dimensional space, the line L3-4 is judged to be normal according to the line fault detection criterion in the step 7, and the detection result is correct.
Case 2A 300 Ω high impedance ground fault occurred when 95% of the lines L4-14 were at 0.6s
The original current-current derivative curves of the 1 st cycle on the 4 side or the 14 side under the high-resistance ground fault of the faulted line L4-14 are shown in fig. 9 and 10.
According to step 1 of the present invention, the original mutation time t on the 4-side of the line L4-14 is obtained00.6002s, original mutation time t on side 1400.6001 s;
according to step 4, the real mutation time t on the 4 side of the line L4-14 is obtained10.6003s, true mutation time t on side 1410.6002 s;
according to step 5, the real mutation time t on the 4-side of the line L4-14 is obtained1Real end time t of the last 1 st 1/4 th cycle20.6048s, true mutation time t on side 141Real end time t of the last 1 st 1/4 th cycle20.6048s, from which two sides t can be seen1To t2Theoretically, the period 1/4 is 0.005s, and actually 0.6048-0.6003-0.0045 s and 0.6048-0.6002-0.0046 s, respectively.
According to the step 6, calculating to obtain that the quadrant satisfaction rate F of the 4 side of the line L4-14 is 95.7 and is greater than the threshold 90, and determining that the current derivative of the 1 st 1/4 cycle after the sudden change of the current of the 4 side is located in the 1 st quadrant of the current-current derivative two-dimensional space; and calculating to obtain a quadrant satisfaction rate F of the 14 side, which is 95.7 and is greater than a threshold value 90, and determining that the current derivative of the 1 st 1/4 th period after the current on the 14 side is suddenly changed is located in the 1 st quadrant of the two-dimensional space of the current-current derivative.
And (4) judging the fault of the line L4-14 according to the line fault detection criterion in the step (7), wherein the detection result is correct.
In the case of a high-resistance ground fault on the line L4-14, the original current-current derivative curves for the 1 st cycle on either side 3 or 4 are shown in fig. 11 and 12.
According to step 1 of the present invention, the original mutation time t on the 3 side of the line L3-4 is obtained00.6001s, original mutation time t on side 400.6002 s;
according to step 4, the true mutation time t on the 3 side of the line L3-4 is obtained10.6002s, true mutation time t on side 410.6004 s;
according to step 5, the true mutation time t on the 3 side of the line L3-4 is obtained1Real end time t of the last 1 st 1/4 th cycle20.6048s, true mutation time t on side 41Real end time t of the last 1 st 1/4 th cycle20.6048s, from which two sides t can be seen1To t2Theoretically, the period 1/4 is 0.005s, and actually 0.6048-0.6002-0.0046 s and 0.6048-0.6004-0.0044 s, respectively.
According to the step 6, calculating to obtain that the quadrant satisfaction rate F of the 3 side of the line L3-4 is 97.9 and is greater than the threshold 90, and determining that the current derivative of the 1 st 1/4 cycle after the current of the 3 side is suddenly changed is located in the 3 rd quadrant of the current-current derivative two-dimensional space; and calculating to obtain a quadrant satisfaction rate F of the 4 side, wherein the quadrant satisfaction rate F is 100 and is larger than a threshold value 90, and determining that the current derivative of the 1 st 1/4 th period after the 4 side current mutation is located in the 1 st quadrant of the current-current derivative two-dimensional space.
After the current on the two sides of the line L3-4 suddenly changes, the current derivatives in the 1 st 1/4 cycle are respectively located in the 1 st quadrant and the 3 rd quadrant of the current-current derivative two-dimensional space, and according to the line fault detection criterion in the step 7, the line L3-4 is judged to be normal, and the detection result is correct.
It can be seen from case 1 and case 2 that in the event of a metallic ground fault, the current is 21.579kA at the maximum, the current derivative is 4495.0kA/s at the maximum, and the 1 st 1/4 th cycle after the current jump is 1/4 cycles 0.005s at the theoretical maximum, and actually 0.0076s at the maximum, which is longer than 1/4 cycles, but does not exceed half the cycle 0.01 s.
When a 300 omega high-resistance earth fault occurs, the current is only 0.26kA at most, the current derivative is only 271kA/s at most, which is greatly different from the value of metallic earth in case 1, and the 1 st 1/4 period after the current mutation is 0.005s in 1/4 period theoretically and 0.0046s at most actually, which is relatively close to 1/4 period.
Nevertheless, in the two cases, the current derivatives of the 1 st 1/4 th cycle after the current on both sides of the fault line suddenly changes are in the 1 st quadrant and have the same change trend, while the current derivatives of the 1 st 1/4 th cycle after the current on both sides of the normal line suddenly changes are in the 1 st and 3 rd quadrants respectively and have the same change trend, so that the method is verified to be effective in detecting the fault line.
The judgment of the fault line cannot be influenced due to the fact that the mutation moments on the two sides of the line are not consistent, and the detection effect cannot be influenced due to the fact that the signal is not synchronous, so that the fault line detection method has strong anti-asynchronization capacity.

Claims (1)

1. The power transmission line fault detection method based on the current-current derivative two-dimensional space comprises the following steps:
step one, setting current sampling points in two substations on two sides of a power transmission line to be detected for faults, respectively sampling line currents on two sides of the power transmission line, extracting three-phase current signals of each sampling moment and two cycles before the sampling moment, and calculating each phase current abrupt change delta i at each momentk＝||ik-ik-N|-|ik-N-ik-2NWhere N is the number of samples in a sampling period T, ikIs the current sample value at the k-th instant, ik-NIs the current sample value at the k-N time, ik-2NIs the current sampling value at the k-2N moment; according to the conventional current mutation starting criterion, if the current mutation on one side is larger than the threshold value, starting the subsequent fault detection, and recording the moment as the original mutation moment t0If not, returning to the first step;
step two, extracting the phase with the largest three-phase current mutation quantity on two sides of the power transmission line from the original mutation time t0To t0+1/4 period, calculating the current derivative of each phase, and recording the current derivative i of k timeDkI.e. iDk＝(ik-ik-1) A,/Δ t, wherein ik、ik-1Current sampling values at the kth moment and the kth-1 moment respectively, wherein delta t is the time difference between two adjacent sampling moments;
step three, aiming at the original mutation moment t at one side of the power transmission line0To
Figure FDA0002245516120000011
The current derivative at each moment is checked to see if it is greater than 0, and if it is greater than 0, 1 count is made; after the statistics is finished,if the total count is greater than
Figure FDA0002245516120000012
The original mutation time t of the side is preliminarily judged0To
Figure FDA0002245516120000013
Is located in quadrant 1 of the two-dimensional space of the current-current derivative, and is marked as that the current derivative of the 1 st 1/4 cycle on the side is located in quadrant 1;
otherwise, for the original mutation moment t of the side of the power transmission line0To
Figure FDA0002245516120000014
Checking the current derivative at each moment in turn whether the current derivative is less than 0, and counting for 1 time if the current derivative is less than 0; when the statistics are finished, if the total count is larger than
Figure FDA0002245516120000015
The original mutation time t of the side is preliminarily judged0To
Figure FDA0002245516120000016
Is located in quadrant 3 of the two-dimensional space of the current-current derivative, and is marked as that the current derivative of the 1 st 1/4 cycle on the side is located in quadrant 3;
in the same way, processing the current derivative of the other side of the transmission line, and preliminarily judging the quadrant of the current derivative of the 1 st 1/4 period on the side in the two-dimensional space of the current-current derivative;
step four, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, the original mutation moment t from the side0Firstly, checking whether the current derivative of each time and two continuous times after each time is simultaneously greater than 0 or not in sequence, and if the condition is met, defining the time as the real sudden change time t of the side1And stopping the inspection;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is positioned in the 3 rd quadrant, the original sudden change moment on the sidet0Firstly, checking whether the current derivative of each time and two continuous time after each time is less than 0 at the same time in sequence, and if the condition is met, defining the time as the real sudden change time t of the side1And stopping the inspection;
in the same way, the original mutation time t at the other side of the transmission line is processed0To
Figure FDA0002245516120000017
Finding the true abrupt change time t of the side1(ii) a This eliminates the original mutation time t0After t0And t1The current derivative of the random disturbance present in between;
step five, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, aiming at the side from the real mutation moment t1To
Figure FDA0002245516120000018
Is greater than 0, and the current derivatives of 3 consecutive moments thereafter are all less than 0 at the same time, and if this condition is met, the moment is defined as the true sudden change moment t of the side1True end t of the last 1 st 1/4 th cycle2And stopping the inspection;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is positioned in the 3 rd quadrant, the current derivative is positioned from the real sudden change time t on the side1To
Figure FDA0002245516120000021
The current derivative of each time is checked whether the current derivative of each time is less than 0, and the current derivatives of 3 subsequent times are all greater than 0 at the same time, if the condition is met, the time is defined as the real sudden change time t of the side1True end t of the last 1 st 1/4 th cycle2And stopping the inspection;
in the same way, the current derivative of the other side of the transmission line is processed to find the real end time t of the 1 st 1/4 cycle of the side2(ii) a This eliminates the actual mutation time t1Then the derivative of the current which fluctuates around the 1 st 1/4 th period is found, and the real end time t of the 1 st 1/4 th periods on both sides is found2；
Step six, if the 1 st 1/4 cycle current derivative on one side of the power transmission line is positioned in the 1 st quadrant, the current derivative on the side is subjected to real sudden change from the time t1To the real end of the 1 st 1/4 th cycle2The current derivative at each moment is checked whether it is greater than 0, and if it is greater than 0, the total count C is increased by 1; when the statistics are finished, dividing C by t1To t2The number Num of the sampling points (i.e. Num ═ t)2-t1) And/delta T, obtaining a quadrant satisfaction rate F, namely F is T/Num 100, and if the quadrant satisfaction rate F is greater than a threshold value 90, accurately judging the real mutation time T of the side1The derivative of the current for the second 1 st 1/4 th cycle is in quadrant 1;
if the 1 st 1/4 cycle current derivative on one side of the transmission line is in quadrant 3, then the t is determined for the side1To t2Respectively checking whether it is less than 0, and if it is less than 0, adding 1 to the total count C; when the statistics are finished, dividing C by t1To t2The number Num of the sampling points (i.e. Num ═ t)2-t1) And/delta t, obtaining a quadrant satisfaction rate F, namely F is C/Num 100, and if the quadrant satisfaction rate F is greater than a threshold value 90, accurately judging the real mutation time t of the side1The derivative of the current for the last 1 st 1/4 th cycle is in quadrant 3;
in the same way, the current derivative of the other side of the power transmission line is processed, and the real mutation moment t of the side is accurately judged1The quadrant in which the current derivative of the last 1 st 1/4 cycles resides;
seventhly, transmitting the quadrant where the current derivative of the 1 st 1/4 th cycle is located to a protection device of the opposite side through an optical fiber channel or a wide area communication network on two sides of the power transmission line; establishing line fault detection criterion if real sudden change time t of two sides of the transmission line1Judging that the line has a fault if the current derivatives of the last 1 st 1/4 th period are all located in the 1 st quadrant;
if the real sudden change moment t of one side of the transmission line1Current derivative position of last 1 st 1/4 th cycleIn quadrant 1, while the other side really changes abruptly at time t1And if the current derivative of the last 1 st 1/4 th period is in the 3 rd quadrant, judging the line to be normal, and returning to the step one.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0083772A1 (en) * 1982-01-13 1983-07-20 Westinghouse Electric Corporation Protective relay apparatus
JPH1062486A (en) * 1996-04-17 1998-03-06 Eaton Corp Series arc failure detection device of ac circuit
WO2001002872A1 (en) * 1999-07-01 2001-01-11 Square D Company A method and system for detecting arcing faults and testing such system
CN101587159A (en) * 2009-06-22 2009-11-25 昆明理工大学 Power distribution network outgoing feeder fault route selecting method by S transform amplitude detection
CN103368152A (en) * 2013-06-18 2013-10-23 国家电网公司 Power transmission line single phase high-resistance grounding fault current protective method
CN103683230A (en) * 2013-12-18 2014-03-26 重庆大学 Method and structure for achieving distance protection of power distribution network of power system
CN103809082A (en) * 2014-02-17 2014-05-21 四川大学 Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation
CN105552881A (en) * 2015-12-08 2016-05-04 东北电力大学 Alternating current system multi-frequency oscillation composite out-of-step separation criterion method based on wide area measurement information
CN109669096A (en) * 2019-01-24 2019-04-23 济南大学 The single loop line method for locating single-phase ground fault of double circuits on same tower transmission line of electricity
CN110350493A (en) * 2019-06-25 2019-10-18 哈尔滨工业大学 Middle pressure flexible direct current system fault detection method based on line current second dervative

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0083772A1 (en) * 1982-01-13 1983-07-20 Westinghouse Electric Corporation Protective relay apparatus
JPH1062486A (en) * 1996-04-17 1998-03-06 Eaton Corp Series arc failure detection device of ac circuit
WO2001002872A1 (en) * 1999-07-01 2001-01-11 Square D Company A method and system for detecting arcing faults and testing such system
CN101587159A (en) * 2009-06-22 2009-11-25 昆明理工大学 Power distribution network outgoing feeder fault route selecting method by S transform amplitude detection
CN103368152A (en) * 2013-06-18 2013-10-23 国家电网公司 Power transmission line single phase high-resistance grounding fault current protective method
CN103683230A (en) * 2013-12-18 2014-03-26 重庆大学 Method and structure for achieving distance protection of power distribution network of power system
CN103809082A (en) * 2014-02-17 2014-05-21 四川大学 Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation
CN105552881A (en) * 2015-12-08 2016-05-04 东北电力大学 Alternating current system multi-frequency oscillation composite out-of-step separation criterion method based on wide area measurement information
CN109669096A (en) * 2019-01-24 2019-04-23 济南大学 The single loop line method for locating single-phase ground fault of double circuits on same tower transmission line of electricity
CN110350493A (en) * 2019-06-25 2019-10-18 哈尔滨工业大学 Middle pressure flexible direct current system fault detection method based on line current second dervative

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
D. D. PATEL 等: "Transformer inrush/internal fault identification based on average angle of second order derivative of current", 《2017 IEEE PES ASIA-PACIFIC POWER AND ENERGY ENGINEERING CONFERENCE (APPEEC)》 *
韩迎春 等: "利用时空电气量基于灰色关联度的电网故障诊断", 《电网技术》 *

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