CN112684279B - Phase current similarity-based power distribution network single-phase earth fault detection algorithm - Google Patents
Phase current similarity-based power distribution network single-phase earth fault detection algorithm Download PDFInfo
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Abstract
The invention provides a power distribution network single-phase earth fault detection algorithm based on phase current similarity. Firstly, acquiring current sampling data in td time before and after a single-phase earth fault moment according to a three-phase current acquisition terminal installed in a power distribution network, and synthesizing a current mutation sequence; calculating the HD distance between the current break variables of each acquisition terminal according to the characteristics that the waveform similarity between the current break variables of the fault point near the bus is low and the waveform similarity between the current break variables of the fault point near the load is high; judging a fault feeder line according to the similarity of the current break variables of the current acquisition terminals of the feeder lines closest to the bus; judging whether the acquisition terminal is positioned at the side close to a bus or the side close to a load of a fault point according to the similarity of the current break variables of the current acquisition terminal of the fault feeder line, and determining the fault position; and finally, realizing fault phase selection through the similarity of three-phase current break variables at the fault point. The method can avoid the influence caused by a branch line and a cable overhead mixed line, and has bootstrap property.
Description
Technical Field
The invention relates to a power distribution network single-phase earth fault detection algorithm based on phase current similarity.
Background
The existing single-phase earth fault section positioning method of the non-effective earth distribution network can be divided into 2 types according to different utilization information: the method comprises the following steps of firstly, positioning a fault section based on an external injection signal; and secondly, the electrical quantity change characteristics at the fault moment are utilized to carry out fault section positioning, and the fault section positioning can be divided into a fault section positioning method based on a fault steady-state component, a fault section positioning method based on a fault transient-state component and a comprehensive information positioning method. According to practical application experience, the medium-voltage distribution network is complex in structure and multiple in line branches. The characteristics of the phase current and the current collected before and after the branch line node can be greatly changed; in a mixed line of a cable and an overhead line, the phase current before and after a junction position also has large change; in addition, the power distribution network in the mountainous area has the characteristic of poor communication conditions. The practicability of the traditional section positioning method based on the similarity of the uploaded phase current and current characteristics is seriously influenced.
Disclosure of Invention
The invention aims to provide a power distribution network single-phase grounding fault detection algorithm based on phase current similarity, which can overcome the problems in the background art and realize the positioning of an effective section of the power distribution network single-phase grounding.
In order to solve the technical problems, the invention is realized by the following technical scheme: a power distribution network single-phase earth fault detection algorithm based on phase current similarity comprises the following steps:
step 1:
three-phase current data in two periods of 1 and 1 after the moment of single-phase ground fault are obtained by using three-phase current acquisition equipment installed in a small-current grounding power distribution network containing m feeders, the sampling frequency f of the three-phase current data is 8kHz, the ith feeder is provided with ni three-phase current acquisition terminals, and the whole power distribution network has a total of three-phase current acquisition terminals
An acquisition terminal; therefore, three-phase current sequences of each acquisition terminal are formed, and the jth three-phase current sequence in the ith feeder line is represented by i (i, j); the phase current sampling number of each phase current sequence comprises that N is 320 in the period 1 before the fault moment and in the period 1 after the fault moment; the j th three-phase current sudden change sequence in the ith feeder line is represented by i0(i, j) indicates that it contains a data number NS of 160;
step 2:
three-phase current break variable i of three-phase current acquisition terminal closest to bus on m feeders of power distribution network0(i, j) are numbered sequentially and are i respectively0(1，1)、i0(2，1)、……、i0(i，1)、……、i0(m，1)；
Sequentially numbering the three-phase current break variables of the ni three-phase current acquisition terminals of the ith feeder line from the bus to the load, wherein the serial number of the trunk line is i0(i，1)、i0(i，2)、……、i0(i，j)、……i0(i, k) branch line number i0(i，k+1)、i0(i，k+2)、……、i0(i，ni)；
Three-phase current acquisition terminal on feeder line iThe phase current sequence i (i, j) collected by the terminal obtains the three-phase current break variable sequence i at each collection terminal0(i，j)；
And step 3:
the three-phase current acquisition terminal continuously acquires current of a line to generate a three-phase current mutation quantity sequence, when 40 pieces of data in a certain phase current mutation quantity sequence are more than 5A, the system is judged to possibly have faults, each current acquisition terminal provides three-phase current mutation quantity recorded wave data, and a collecting unit synthesizes three-phase current mutation quantity waveforms; for the three-phase current sequence, calculating a first periodic wave current effective value I after the fault through a full-period Fourier algorithm1(i, j) is greater than 150A;
1) if I1(i，j)>150A, judging that an interphase short circuit fault possibly occurs, and turning to step 4;
2) if I1(i，j)<150A, judging that the single-phase earth fault possibly occurs, and turning to the step 5;
and 4, step 4:
for the three-phase current sequence, calculating the effective value I of the periodic wave current before the fault through a full-period Fourier algorithm2(I, j) is greater than 0A, if I2(i, j) is not more than 0A, judging that reclosing inrush current exists, and otherwise, continuing the process;
judging whether the line trips within 0.6s, if the line does not trip, judging that disturbance occurs, otherwise, judging that short-circuit fault occurs, lighting an LED signal lamp of a fault indicator acquisition unit, setting a sign signal to be 1, and setting the sign signal to be 0 when the fault does not occur;
judging whether the circuit reclosing is successful, if so, judging the circuit reclosing to be an instantaneous short-circuit fault, otherwise, judging the circuit reclosing to be a permanent short-circuit fault;
a three-phase current acquisition terminal with a signal 1 is marked with a number uploading and main station setting, the number of a feeder line is set to be x, the maximum number on the feeder line x is set to be y, a fault section is between an acquisition unit (x, y) and an acquisition unit (x, y +1), and fault positioning is finished;
and 5:
three-phase current break variable sequence acquired by current acquisition terminal closest to bus of m feeders of power distribution networki0(1，1)、i0(2，1)、……、i0(m, 1) carrying out similarity analysis among three phases in each sequence; the specific content is that the Hausdroff algorithm is utilized to calculate the similarity H between every two of three phases A, B and C in each sequenceAB、HBC、HCAThen, calculating a three-phase current break variable sequence i of the circuit acquisition terminal of each feeder line i closest to the bus0(i,1) similarity
The larger the similarity value is, the more dissimilar the waveforms are;
is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]Wherein
i0(A) (a) a-th number of A-phase current mutation value sequences, i0(B) (B) the number B of the B-th phase current abrupt change variable sequences is shown, and the BC interphase similarity H can be obtained in the same wayBCSimilarity between phases and CA HCA(ii) a If it is
The feeder u is a fault feeder;
step 6:
sequentially calculating the similarity among three phases A, B and C in a three-phase current break variable sampling sequence of the 1 st, 2 nd, … … th and nu collection terminals on the fault feeder line u
Similarity of three-phase current break variable of any r-th acquisition unit on line
Is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]Wherein
i0(A) (a) a-th number, i, of A-phase current abrupt change quantity sequences0(B) (B) the number B of the B-th phase current abrupt change amount sequence; the similarity H between BC phases can be obtained by the same methodBCSimilarity to CA phase HCA；
If it is
If the number of the acquisition units is less than 0.6, the r acquisition unit is judged to be positioned behind the fault point, and if the number of the acquisition units is less than 0.6
If the number is more than 0.6, judging that the r-th acquisition unit is positioned in front of a fault point, lighting an LED signal lamp of a fault indicator acquisition unit (or a distribution automation terminal), setting a sign signal to be 1, and setting the sign signal to be 0 when the fault is not generated;
a three-phase current acquisition terminal with a mark signal of 1 uploads a number and is provided with a master station, and if the maximum number on a feeder u is p, a fault section is between an acquisition unit (u, p) and an acquisition unit (u, p + 1);
and 7:
after the fault interval is determined to be between the p-th acquisition unit and the p + 1-th acquisition unit of the line u in the step 6, fault phase selection is carried out;
the specific content is that firstly, the average similarity P of fault current break variables of each phase of the 1 st acquisition unit of the fault feeder line u is calculatedA、PB、PCThe calculation formula is
Get P in the same wayBAnd PC(ii) a Secondly, calculating the fault evaluation index lambda of each phaseA，λB，λCThe calculation formula is lambdaA＝|PA-PB|+|PC-PAI, similarly can get λB，λC(ii) a And the phase corresponding to the maximum value of the fault evaluation index is the fault phase.
Compared with the prior art, the invention has the advantages that:
(1) the phase current abrupt change quantity synthesized by the line phase current acquisition terminal when a fault occurs is utilized to carry out Hausdroff similarity analysis, a large amount of wave recording data transmission with a power distribution network operation and maintenance main station server is not needed, and the on-site detection of the single-phase earth fault under the condition of no communication can be realized.
(2) The method has the advantages that the similarity among the three phases A, B and C in the three-phase current abrupt change sequence of each sampling terminal at the fault moment is calculated by utilizing a Hausdroff algorithm, the relative position of the sampling point and the fault point is determined, the problem of section positioning misjudgment caused by the waveform similarity abrupt change before and after the branch point of the line and the overhead cable connection point can be solved, and the method is high in accuracy and strong in adaptability.
(3) The phase current in two periods before and after the fault occurs is sampled by using the 8kHz sampling rate technology and the three-phase time accurate synchronization technology, so that all data of the fault transient process can be utilized, the defect of less effective information when only single criteria such as amplitude or phase are used is avoided, and the fault identification rate can be obviously improved.
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FIG. 1: the structure schematic diagram of the 10kV low-current grounding power distribution network adopted in the embodiment of the invention (black points represent sampling points).
Detailed Description
The invention discloses an embodiment of a power distribution network single-phase earth fault detection algorithm based on phase current similarity, which comprises the following steps of:
step 1:
three-phase current acquisition installed in low-current grounding power distribution network containing m feeder linesThe device acquires three-phase current data in two periods of 1 before and 1 after the single-phase earth fault moment, the sampling frequency f of the three-phase current data is 8kHz, the ith feeder line is provided with ni three-phase current acquisition terminals, and the whole power distribution network has a total of
An acquisition terminal; therefore, three-phase current sequences of each acquisition terminal are formed, and the jth three-phase current sequence in the ith feeder line is represented by i (i, j); the phase current sampling number of each phase current sequence comprises a period 1 before the fault moment and a period 1 after the fault moment, and N is 320; the j (th) three-phase current mutation quantity sequence in the ith feeder line is i0(i, j) indicates that it contains a data number NS of 160;
step 2:
three-phase current abrupt change i of three-phase current acquisition terminal closest to bus on m feeder lines of power distribution network0(i, j) are numbered sequentially and are i respectively0(1，1)、i0(2，1)、……、i0(i，1)、……、i0(m，1)；
Sequentially numbering the three-phase current break variables of the ni three-phase current acquisition terminals of the ith feeder line from the bus to the load, wherein the serial number of the trunk line is i0(i，1)、i0(i，2)、……、i0(i，j)、……i0(i, k) branch line number i0(i，k+1)、i0(i，k+2)、……、i0(i，ni)；
Obtaining a three-phase current abrupt change sequence i (i, j) at each acquisition terminal according to a phase current sequence i (i, j) acquired by a three-phase current acquisition terminal on a feeder line i0(i，j)；
And 3, step 3:
the three-phase current acquisition terminal continuously acquires current of a line to generate a three-phase current mutation quantity sequence, when 40 pieces of data in a certain phase current mutation quantity sequence are more than 5A, the system is judged to possibly have faults, each current acquisition terminal provides three-phase current mutation quantity recorded wave data, and a collecting unit synthesizes three-phase current mutation quantity waveforms; for the three-phase current sequence, calculating the first time after the fault by a full-period Fourier algorithmEffective value of cyclic current I1(i, j) is greater than 150A;
1) if I1(i，j)>150A, judging that an interphase short circuit fault possibly occurs, and turning to step 4;
2) if I1(i，j)<150A, judging that the single-phase earth fault possibly occurs, and turning to the step 5;
and 4, step 4:
for the three-phase current sequence, calculating the effective value I of the periodic wave current before the fault through a full-period Fourier algorithm2(I, j) is greater than 0A, if I2(i, j) is not more than 0A, judging that reclosing inrush current exists, and otherwise, continuing the process;
judging whether the line trips within 0.6s, if the line does not trip, judging that disturbance occurs, otherwise, judging that short-circuit fault occurs, lighting an LED signal lamp of a fault indicator acquisition unit, setting a sign signal to be 1, and setting the sign signal to be 0 when the fault does not occur;
judging whether the circuit reclosing is successful, if so, judging the circuit reclosing to be an instantaneous short-circuit fault, otherwise, judging the circuit reclosing to be a permanent short-circuit fault;
a three-phase current acquisition terminal with a signal 1 is marked with a number uploading and main station setting, the number of a feeder line is set to be x, the maximum number on the feeder line x is set to be y, a fault section is between an acquisition unit (x, y) and an acquisition unit (x, y +1), and fault positioning is finished;
and 5:
three-phase current abrupt change sequence i acquired by current acquisition terminal closest to bus of m feeder lines of power distribution network0(1，1)、i0(2，1)、……、i0(m, 1) carrying out similarity analysis among three phases in each sequence;
the specific content is that the Hausdroff algorithm is utilized to calculate the similarity H between every two of three phases A, B and C in each sequenceAB、HBC、HCAThen, calculating a three-phase current break variable sequence i of the circuit acquisition terminal of each feeder line i closest to the bus0(i,1) similarity
The greater the value of the degree of similarity is,the more dissimilar the waveforms are;
is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]Wherein
i0(A) (a) a-th number of A-phase current mutation value sequences, i0(B) (B) the number B of the B-th phase current abrupt change variable sequences is shown, and the BC interphase similarity H can be obtained in the same wayBCSimilarity to CA phase HCA(ii) a If it is
The feeder u is a fault feeder;
and 6:
sequentially calculating the similarity among three phases A, B and C in a three-phase current break variable sampling sequence of the 1 st, 2 nd, … … th and nu collection terminals on the fault feeder line u
Similarity of three-phase current break variable of any r-th acquisition unit on line
Is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]Wherein
i0(A) (a) a-th number, i, of A-phase current abrupt change quantity sequences0(B) (B) the number B of the B-th phase current abrupt change amount sequence; the similarity H between BC phases can be obtained by the same methodBCSimilarity to CA phase HCA；
If it is
If the signal is less than 0.6, judging that the r-th acquisition unit is positioned behind the fault point, and if the signal is less than the fault point
If the number is more than 0.6, judging that the r-th acquisition unit is positioned in front of a fault point, lighting an LED signal lamp of a fault indicator acquisition unit (or a distribution automation terminal), setting a sign signal to be 1, and setting the sign signal to be 0 when the fault is not generated;
a three-phase current acquisition terminal with a mark signal of 1 uploads a number and is provided with a master station, and if the maximum number on a feeder u is p, a fault section is between an acquisition unit (u, p) and an acquisition unit (u, p + 1);
and 7:
after the fault interval is determined to be between the p-th acquisition unit and the p + 1-th acquisition unit of the line u in the step 6, fault phase selection is carried out;
the specific content is that firstly, the average similarity P of fault current break variables of each phase of the 1 st acquisition unit of the fault feeder line u is calculatedA、PB、PCThe calculation formula is
Get P in the same wayBAnd PC(ii) a Secondly, calculating the fault evaluation index lambda of each phaseA，λB，λCThe calculation formula is lambdaA＝|PA-PB|+|PC-PAI, similarly can get λB，λC(ii) a And the phase corresponding to the maximum value of the fault evaluation index is the fault phase.
The present invention is explained in more detail below by means of examples, which are only illustrative and the scope of protection of the present invention is not limited by these examples.
A10 kV low-current grounding power distribution network is shown in figure 1, and is provided with 6 outgoing lines in total, and a feeder line is composed of an overhead line and a cable. The line 1 is an overhead line-cable hybrid line, a main line consists of 20km overhead lines and 10km cables, and a 10km cable branch line is arranged; lines 2, 3 and 4 are cable lines and lines 5 and 6 are overhead lines. The switch K can control the switching of the arc suppression coil, and the overcompensation degree is 10%.
The method for locating the single-phase earth fault section of the power distribution network based on the phase current similarity is described below with reference to an example, assuming that a single-phase earth fault occurs at a fault point through a transition resistance Rf of 1000 Ω. Examples are as follows:
1) a phase grounding faults occur between sampling points 1-7 and sampling points 1-8 of a main line of a feeder 1;
2) a phase grounding fault occurs between sampling points 1-9 and sampling points 1-10 of a feeder 1 branch line;
the specific process is as follows:
a phase grounding fault occurs between sampling points 1-7 and 1-8 of main line of feeder 1
Firstly, three-phase current data within 20ms before and 20ms after a fault moment are obtained by using a three-phase current acquisition terminal (a transient recording type fault indicator or a power distribution automation terminal device) installed on a power distribution network, and a three-phase current mutation sequence is synthesized, wherein the number NS of sequence data of one phase current mutation is 160.
Secondly, calculating the first periodic wave current effective value I after the fault by a full-period Fourier algorithm for the three-phase current sequence1(i，j)＝29.7A。I1(i，j)<150A, judging that the system has single-phase earth fault.
Thirdly, sequentially calculating a three-phase current break variable sequence i of the line acquisition terminal with each feeder line i closest to the bus0(i,1) similarity between internal three phases
And if the maximum value is located on the feeder line 1, determining that the fault line is the feeder line 1.
Fourthly, sequentially calculating the similarity among the three phases A, B and C in the three-phase current abrupt change sampling sequence of the 1 st, 2 nd, … … th and 10 th acquisition devices on the fault feeder line 1
And the acquisition terminals with the similarity greater than 0.6 are respectively numbered as 1, 2, 3, 4, 5, 6 and 7, and the maximum value of the number is 7, so that the fault section is judged to be between the acquisition units (1 and 7) and the acquisition units (1 and 8).
Fifthly, calculating fault evaluation indexes of all phases, namely lambda, according to the acquisition units (1, 1)A＝0.39625，λB＝0.21065，λCSince 0.2023, phase a is determined to be the failed phase.
A phase grounding fault occurs between sampling points 1-9 and 1-10 of feeder 1 branch line
Firstly, three-phase current data within 20ms before and 20ms after a fault moment are obtained by using a three-phase current acquisition terminal (a transient recording type fault indicator or a power distribution automation terminal device) installed on a power distribution network, and a three-phase current mutation sequence is synthesized, wherein the number NS of sequence data of one phase current mutation is 160.
Secondly, calculating the first periodic wave current effective value I after the fault by a full-period Fourier algorithm for the three-phase current sequence1(i，j)＝29.9A。I1(i，j)<150A, judging that the system has single-phase earth fault.
Thirdly, sequentially calculating a three-phase current break variable sequence i of the line acquisition terminal with each feeder line i closest to the bus0(i,1) similarity between internal three phases
And if the maximum value is located on the feeder line 1, determining that the fault line is the feeder line 1.
Fourthly, sequentially calculating the similarity among the three phases A, B and C in the three-phase current abrupt change sampling sequence of the 1 st, 2 nd, … … th and 10 th acquisition devices on the fault feeder line 1
And the acquisition terminals with the similarity larger than 0.6 are respectively numbered as 1, 2, 3, 4 and 9, and the maximum value of the number is 9, so that the fault section is judged to be between the acquisition units (1 and 9) and the acquisition units (1 and 10).
Fifthly, calculating fault evaluation indexes of all phases, namely lambda, according to the acquisition units (1, 1)A＝0.3967，λB＝0.1991，λCSince 0.1986, phase a is determined to be the failed phase.
The invention provides a new method, which comprises the steps of firstly, acquiring three-phase current sampling data in td time before and after a single-phase ground fault moment according to a three-phase current acquisition terminal (a transient recording type fault indicator or a distribution automation terminal) installed in a power distribution network, and synthesizing a three-phase current mutation sequence; calculating the HD distance between the three-phase current sudden changes of each acquisition terminal according to the characteristics that the waveform similarity between the three-phase current sudden changes at the fault point side close to the bus is low and the waveform similarity between the three-phase current sudden changes at the fault point side close to the load is high; judging a fault feeder line according to the similarity of the three-phase current break variables of the three-phase current acquisition terminal of which each feeder line is closest to the bus; judging whether the acquisition terminal is positioned at the side close to the bus of the fault point or the side close to the load according to the similarity of the three-phase current break variables of the three-phase current acquisition terminal of the fault feeder line, and determining the fault position; and finally, realizing fault phase selection through the similarity of three-phase current break variables at the fault point. The method can avoid the influence caused by a branch line and a cable overhead mixed line, and has bootstrap property.
The above description is only an embodiment of the present invention, but the technical features of the present invention are not limited thereto, and any changes or modifications within the technical field of the present invention by those skilled in the art are covered by the claims of the present invention.
Claims (1)
1. A distribution network single-phase earth fault detection algorithm based on phase current similarity is characterized in that: the method comprises the following steps:
step 1:
three-phase current data in two periods of 1 and 1 after the moment of single-phase ground fault are obtained by using three-phase current acquisition equipment installed in a small-current grounding power distribution network containing m feeders, the sampling frequency f of the three-phase current data is 8kHz, the ith feeder is provided with ni three-phase current acquisition terminals, and the whole power distribution network has a total of three-phase current acquisition terminals
An acquisition terminal; therefore, three-phase current sequences of each acquisition terminal are formed, and the jth three-phase current sequence in the ith feeder line is represented by i (i, j); the phase current sampling number of each phase current sequence comprises that N is 320 in the period 1 before the fault moment and in the period 1 after the fault moment; the j (th) three-phase current mutation quantity sequence in the ith feeder line is i0(i, j) indicates that it contains a data number NS of 160;
step 2:
sudden change of three-phase current acquisition terminal closest to bus on m feeders of power distribution networkQuantity i0(i, j) are numbered sequentially and are i respectively0(1，1)、i0(2，1)、……、i0(i，1)、……、i0(m，1)；
Sequentially numbering the three-phase current break variables of the ni three-phase current acquisition terminals of the ith feeder line from the bus to the load, wherein the serial number of the trunk line is i0(i，1)、i0(i，2)、……、i0(i，j)、……i0(i, k) branch line number i0(i，k+1)、i0(i，k+2)、……、i0(i，ni)；
Obtaining a three-phase current abrupt change sequence i (i, j) at each acquisition terminal according to a phase current sequence i (i, j) acquired by a three-phase current acquisition terminal on a feeder line i0(i，j)；
And step 3:
the three-phase current acquisition terminal continuously acquires current of a line to generate a three-phase current mutation quantity sequence, when 40 pieces of data in a certain phase current mutation quantity sequence are more than 5A, the system is judged to possibly have faults, each current acquisition terminal provides three-phase current mutation quantity recorded wave data, and a collecting unit synthesizes three-phase current mutation quantity waveforms; for the three-phase current sequence, calculating a first cycle current effective value I after the fault through a full-cycle Fourier algorithm1(i, j) is greater than 150A;
1) if I1(i，j)>150A, judging that an interphase short circuit fault possibly occurs, and turning to step 4;
2) if I1(i，j)<150A, judging that the single-phase earth fault possibly occurs, and turning to the step 5;
and 4, step 4:
for the three-phase current sequence, calculating an effective value I of a cycle wave current before a fault through a full-cycle Fourier algorithm2(I, j) is greater than 0A, if I2(i, j) is not more than 0A, judging that reclosing inrush current exists, and otherwise, continuing the process;
judging whether the line trips within 0.6s, if the line does not trip, judging that disturbance occurs, otherwise, judging that short-circuit fault occurs, lighting an LED signal lamp of a fault indicator acquisition unit, setting a sign signal to be 1, and setting the sign signal to be 0 when the fault does not occur;
judging whether the circuit reclosing is successful, if so, judging the circuit reclosing to be an instantaneous short-circuit fault, otherwise, judging the circuit reclosing to be a permanent short-circuit fault;
a three-phase current acquisition terminal with a signal 1 is marked with a number uploading and main station setting, the number of a feeder line is set to be x, the maximum number on the feeder line x is set to be y, a fault section is between an acquisition unit (x, y) and an acquisition unit (x, y +1), and fault positioning is finished;
and 5:
three-phase current break variable sequence i acquired by current acquisition terminal closest to bus of m feeders of power distribution network0(1，1)、i0(2，1)、……、i0(m, 1) carrying out similarity analysis among three phases in each sequence; the specific content is that the Hausdroff algorithm is utilized to calculate the similarity H between every two of three phases A, B and C in each sequenceAB、HBC、HCAThen, calculating a three-phase current break variable sequence i of the circuit acquisition terminal of each feeder line i closest to the bus0(i,1) similarity
The larger the similarity value is, the more dissimilar the waveforms are;
is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]In which
i0(A) (a) a-th number, i, of A-phase current abrupt change quantity sequences0(B) (B) the number B of the B-th phase current abrupt change variable sequences is shown, and the BC interphase similarity H can be obtained in the same wayBCSimilarity to CA phase HCA(ii) a If it is
The feeder u is a fault feeder;
step 6:
sequentially calculating the similarity among three phases A, B and C in a three-phase current break variable sampling sequence of the 1 st, 2 nd, … … th and nu collection terminals on the fault feeder line u
Similarity of three-phase current break variable of any r-th acquisition unit on line
Is calculated by the formula
AB interphase similarity HABThe calculation formula is HAB＝max[hAB,hBA]Therein, wherein
i0(A) (a) a-th number, i, of A-phase current abrupt change quantity sequences0(B) (B) the number B of the B-th phase current abrupt change amount sequence; the similarity H between BC phases can be obtained by the same methodBCSimilarity to CA phase HCA；
If it is
If the number of the acquisition units is less than 0.6, the r acquisition unit is judged to be positioned behind the fault point, and if the number of the acquisition units is less than 0.6
If the number is more than 0.6, judging that the r-th acquisition unit is positioned in front of a fault point, lighting a fault indicator acquisition unit or a power distribution automation terminal LED signal lamp, setting a sign signal to be 1, and setting the sign signal to be 0 when the fault point is not detected;
a three-phase current acquisition terminal with a mark signal of 1 uploads a number and is provided with a master station, and if the maximum number on a feeder u is p, a fault section is between an acquisition unit (u, p) and an acquisition unit (u, p + 1);
and 7:
after the fault interval is determined to be between the p-th acquisition unit and the p + 1-th acquisition unit of the line u in the step 6, fault phase selection is carried out;
the specific content is that firstly, the average similarity P of fault current break variables of each phase of the 1 st acquisition unit of the fault feeder line u is calculatedA、PB、PCThe calculation formula is
Get P in the same wayBAnd PC；
Secondly, calculating the fault evaluation index lambda of each phaseA，λB，λCThe formula is lambdaA＝|PA-PB|+|PC-PAI, similarly can get λB，λC(ii) a And the phase corresponding to the maximum value of the fault evaluation index is the fault phase.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2750386A1 (en) * | 1976-11-13 | 1978-05-18 | Sumitomo Electric Industries | DEVICE FOR DETERMINING FAULT ON CABLES |
| JPH01269325A (en) * | 1988-04-21 | 1989-10-26 | Nec Corp | Locating system for cable ground-fault point |
| CN104101812A (en) * | 2013-04-09 | 2014-10-15 | 北京映翰通网络技术股份有限公司 | Single-phase grounding fault detection and positioning method and system for low-current grounding power distribution network |
| CN110988604A (en) * | 2019-12-30 | 2020-04-10 | 武汉理工大学 | Power distribution network single-phase earth fault phase selection method |
| CN111579933A (en) * | 2020-06-03 | 2020-08-25 | 武汉理工大学 | Power distribution network fault section positioning method based on Hausdroff algorithm |
-
2020
- 2020-11-06 CN CN202011229217.1A patent/CN112684279B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2750386A1 (en) * | 1976-11-13 | 1978-05-18 | Sumitomo Electric Industries | DEVICE FOR DETERMINING FAULT ON CABLES |
| JPH01269325A (en) * | 1988-04-21 | 1989-10-26 | Nec Corp | Locating system for cable ground-fault point |
| CN104101812A (en) * | 2013-04-09 | 2014-10-15 | 北京映翰通网络技术股份有限公司 | Single-phase grounding fault detection and positioning method and system for low-current grounding power distribution network |
| CN110988604A (en) * | 2019-12-30 | 2020-04-10 | 武汉理工大学 | Power distribution network single-phase earth fault phase selection method |
| CN111579933A (en) * | 2020-06-03 | 2020-08-25 | 武汉理工大学 | Power distribution network fault section positioning method based on Hausdroff algorithm |
Non-Patent Citations (1)
| Title |
|---|
| "中性点不接地系统单相接地故障综合评判";江勇等;《水利科技》;20101231;全文 * |
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