CN110187241A - A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network - Google Patents

A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network Download PDF

Info

Publication number
CN110187241A
CN110187241A CN201910557993.5A CN201910557993A CN110187241A CN 110187241 A CN110187241 A CN 110187241A CN 201910557993 A CN201910557993 A CN 201910557993A CN 110187241 A CN110187241 A CN 110187241A
Authority
CN
China
Prior art keywords
ground connection
connection medium
dimension
medium type
phase space
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.)
Pending
Application number
CN201910557993.5A
Other languages
Chinese (zh)
Inventor
王科
项恩新
刘红文
聂鼎
徐肖伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Electric Power Research Institute of Yunnan Power Grid Co Ltd
Electric Power Research Institute of Yunnan Power System Ltd
Original Assignee
Electric Power Research Institute of Yunnan Power System Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Electric Power Research Institute of Yunnan Power System Ltd filed Critical Electric Power Research Institute of Yunnan Power System Ltd
Priority to CN201910557993.5A priority Critical patent/CN110187241A/en
Publication of CN110187241A publication Critical patent/CN110187241A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/081Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/088Aspects of digital computing

Abstract

This application provides a kind of determination methods of the ground connection medium type of one-phase earthing failure in electric distribution network, it include: when singlephase earth fault occurs for power distribution network, according to the original time series of the zero-sequence current of one-phase earthing failure in electric distribution network phase, phase space reconfiguration is carried out to the waveform of the zero-sequence current;Determine the optimum delay time of phase space reconstruction;The smallest embedding dimension number of the phase space reconstruction is determined according to the optimum delay time;The correlation dimension of the phase space reconstruction is determined according to the smallest embedding dimension number;The corresponding relationship of the correlation dimension and ground connection medium type that obtain according to the correlation dimension and in advance, determines the ground connection medium type of the singlephase earth fault.Solve the problems, such as that the determination method accuracy of the ground connection medium type of one-phase earthing failure in electric distribution network in the prior art is lower.

Description

A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network
Technical field
This application involves the determination methods of power distribution network ground connection medium type, are specifically related to a kind of power distribution network single-phase earthing event The determination method of the ground connection medium type of barrier.
Background technique
With the rapid development of the national economy, power grid construction scale is also increasing.Power distribution network is that one of power grid is important Component part, there are many kinds of the failures of power distribution network, such as line fault, transformer fault and ground fault etc..Single-phase earthing Failure is a seed type of distribution net work earthing fault.When singlephase earth fault occurs for power distribution network, due to ground connection medium type Difference, the performance characteristic of ground fault will also have biggish difference.Therefore, the ground connection of one-phase earthing failure in electric distribution network is situated between The determination of matter type is particularly important for the judgement and exclusion of ground fault.
Zero-sequence current is a kind of electricity for representative analysis significance that power distribution network occurs when singlephase earth fault occurs Stream, the distortion degree of zero-sequence current will depend on the nonlinear degree of ground connection medium, specifically, ground connection medium nonlinear degree Bigger, the content of higher hamonic wave is more, and the distortion degree of zero-sequence current is bigger.Therefore, to the zero of singlephase earth fault phase Sequence electric current deployment analysis can recognize different types of ground connection medium.In a kind of method for judging distribution net work earthing fault, By analyzing high resistance ground zero-sequence current wave distortion concavity and convexity, to dry floor tile, wetland brick, wet sand, dry crushing stone, Eight kinds of wet rubble, dry tire and wet tire media carry out identification, classification.
However, the smaller and various noise of the zero-sequence current value scene very big with interference after ground fault occurs for power distribution network Under, the concavity and convexity variation of zero-sequence current waveform will be more violent, and the accuracy that will lead to the above method is lower.So providing one The determination method of the ground connection medium of the more acurrate one-phase earthing failure in electric distribution network of kind, becomes those skilled in the art's urgent need to resolve Important technological problems.
Summary of the invention
It is existing to solve this application provides a kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network The lower problem of the ground connection medium determining method accuracy of distribution net work earthing fault.
A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network, comprising:
When power distribution network occur singlephase earth fault when, according to the zero-sequence current of one-phase earthing failure in electric distribution network phase it is original when Between sequence, phase space reconfiguration is carried out to the waveform of the zero-sequence current;
Determine the optimum delay time of phase space reconstruction;
The smallest embedding dimension number of the phase space reconstruction is determined according to the optimum delay time;
The correlation dimension of the phase space reconstruction is determined according to the smallest embedding dimension number;
The corresponding relationship of the correlation dimension and ground connection medium type that obtain according to the correlation dimension and in advance, determine described in The ground connection medium type of singlephase earth fault.
Optionally, the optimum delay time of the determining phase space reconstruction, comprising:
According to state x each in the original time series x (t)iCorresponding Probability px(xi), the x is calculated according to the following formula (t) comentropy H (x):
According to each state q in the time series q (t) after the original time series x (t) delay τjCorresponding probability Pq(qj), the comentropy H (q) of the q (t) is calculated according to the following formula:
According to each state x in the x (t) and q (t)iAnd qjCorresponding joint probability Pxq(xi,qj), it calculates according to the following formula Conditional entropy H (q | x) of the q (t) for x (t):
Wherein, H (x, q) is the q (t) for the combination entropy of the x (t), and the H (x, q) is according to the x (t) and q (t) each state x iniAnd qjCorresponding joint probability Pxq(xi,qj), it is calculated according to the following formula:
According to the I (q, x) obtained by the H (q) and the H (q | x), first local minizing point in I (q, x) is determined Optimum delay time of the corresponding τ as the phase space reconstruction;
Wherein,
Optionally, the smallest embedding dimension number that the phase space reconstruction is determined according to optimum delay time, comprising:
According to the point Y of the phase space reconstructionu(m), calculating matrix a (u, m) according to the following formula:
Wherein, m is the dimension of the phase space reconstruction, Yx(u,m)It (m) is distance Yu(m) nearest point, x (u, m) be greater than 1 and be less than or equal to N-m τ integer;
According to the following formula in calculating matrix a (u, m) all elements mean value E (m):
When the value of the dimension m is greater than m0, and when the value of E (m) will not change, enable the smallest embedding dimension number mb= m0+1。
Optionally, the correlation dimension that the phase space reconstruction is determined according to smallest embedding dimension number, comprising:
According to the smallest embedding dimension number, the point Y (t) in the phase space reconstruction is determined:
Y (t)=y (t), y (t+ τ) ..., y [t+ (mb-1) τ] }, t=1,2 ..., N- (mb-1) τ;
Any one point chosen in N number of point that the phase space reconstruction includes is as a reference point;
The N-1 point in addition to reference point is calculated to the distance of the reference point, is determined small at a distance from the reference point In given value r point be relating dot;
Accounting C of the number of the relating dot in all possible relating dot number N (N-1) is calculated according to the following formulamb (r):
Wherein, Y (i), Y (j) are respectively the ith and jth element in the Y (t), and θ is Heaviside unit function;
According to the Cmb(r) with the relationship of the rCalculate the correlation dimension P.
Optionally, the calculating correlation dimension P includes:
LnC is made under the smallest embedding dimension numbermb(r)=lnr curve determines the uncalibrated visual servo section of the curve, The uncalibrated visual servo section is linear segments or near-linear section, and the uncalibrated visual servo section is fitted to a fitting a straight line, is calculated The slope of the fitting a straight line, using the slope of the fitting a straight line as the correlation dimension P.
Optionally, as steps described below, it obtains correlation dimension in advance and is grounded the corresponding relationship of medium type, comprising:
The zero-sequence current that the one-phase earthing failure in electric distribution network phase of medium type is grounded known to every kind is measured respectively, it is described known Be grounded medium type including at least wet soil, dry earth, wet sand, dry sand ground, wet cement, wet branch and water resistance;
According to the original time series of the zero-sequence current, phase space reconfiguration is carried out to the waveform of the zero-sequence current;
Determine the optimum delay time of phase space reconstruction;
The smallest embedding dimension number of the phase space reconstruction is determined according to the optimum delay time;
The correlation dimension P of the phase space reconstruction is determined according to the smallest embedding dimension numbern:
Wherein, L indicates rinThe total number of value, n indicate ground connection medium type coding, n=1,2,3,4,5,6,7 difference tables With showing ground connection medium water resistance, wet cement, wet soil, wet sand, the coding of wet branch, dry earth and dry sand ground;
According to known ground connection medium type and the correlation dimension, obtains correlation dimension in advance and be grounded pair of medium type It should be related to.
Optionally, the corresponding relationship of the correlation dimension and ground connection medium type, comprising:
Work as P1< P < P2, determine that the ground connection medium type is wet cement;
Work as P2< P < P3, determine the ground connection medium type for wet soil;
Work as P3< P < P4, determine the ground connection medium type for wet sand;
Work as P4< P < P5, determine that the ground connection medium type is wet branch;
Work as P5< P < P6, determine that the ground connection medium type is dry earth;
Work as P6< P < P7, determine that the ground connection medium type is dry sand ground;
As P < P1, determine that the ground connection medium type is water resistance;
Wherein, P is that the corresponding zero-sequence current of unknown ground connection medium passes through the correlation dimension being calculated.
Method provided by the present application, from the angle of the zero-sequence current Wave data of singlephase earth fault phase, using phase Space Reconstruction method analyzes the corresponding zero-sequence current waveform of different ground connection media, according to the optimum delay time of phase space reconstruction Correlation dimension is determined with smallest embedding dimension number, passes through correlation dimension and the correlation dimension and ground connection medium type that in advance obtain Corresponding relationship, determine it is unknown ground connection medium type.Compare the prior art, and this method can more accurately determine single-phase The ground connection medium type of ground fault.
Detailed description of the invention
In order to illustrate more clearly of the technical solution of the application, letter will be made to attached drawing needed in the embodiment below Singly introduce, it should be apparent that, for those of ordinary skills, without any creative labor, It is also possible to obtain other drawings based on these drawings.
The step of Fig. 1 is a kind of confirmation method of ground connection medium of one-phase earthing failure in electric distribution network provided by the present application is illustrated Figure;
Fig. 2 a be grounded medium be wet soil when delay time and mutual information function relation curve;
Fig. 2 b is the relation curve for being grounded delay time and mutual information function when medium is dry earth;
Fig. 2 c be grounded medium be wet sand when delay time and mutual information function relation curve;
Fig. 2 d is the relation curve for being grounded delay time and mutual information function when medium is dry sand ground;
Fig. 2 e be grounded medium be wet cement when delay time and mutual information function relation curve;
Fig. 2 f is the relation curve for being grounded delay time and mutual information function when medium is wet branch;
Fig. 2 g is the relation curve for being grounded delay time and mutual information function when medium is water resistance;
Fig. 3 a be ground connection medium be wet soil when smallest embedding dimension number under lnCmb(r)=lnr curve graph;
Fig. 3 b is ground connection medium lnC under smallest embedding dimension number when being dry earthmb(r)=lnr curve graph;
Fig. 3 c be ground connection medium be wet sand when smallest embedding dimension number under lnCmb(r)=lnr curve graph;
Fig. 3 d is ground connection medium lnC under smallest embedding dimension number when being dry sand groundmb(r)=lnr curve graph;
Fig. 3 e is ground connection medium lnC under smallest embedding dimension number when being wet cementmb(r)=lnr curve graph;
Fig. 3 f is ground connection medium lnC under smallest embedding dimension number when being wet branchmb(r)=lnr curve graph;
Fig. 3 g is ground connection medium lnC under smallest embedding dimension number when being water resistancemb(r)=lnr curve graph.
Specific embodiment
Below in conjunction with the attached drawing in the embodiment of the present application, technical solutions in the embodiments of the present application carries out clear, complete Site preparation description, it is clear that described embodiment is only a part of the embodiment of the application, instead of all the embodiments. Based on the embodiment in the application, those of ordinary skill in the art are obtained without making creative work Every other embodiment, shall fall in the protection scope of this application.
Singlephase earth fault is a seed type of distribution net work earthing fault.When singlephase earth fault occurs for power distribution network, by In the difference of ground connection medium type, the performance characteristic of ground fault will also have biggish difference.Therefore, power distribution network is single-phase The determination of the ground connection medium type of ground fault is particularly important for the judgement and exclusion of ground fault.
Zero-sequence current is a kind of electricity for representative analysis significance that power distribution network occurs when singlephase earth fault occurs Stream, the distortion degree of zero-sequence current will depend on the nonlinear degree of ground connection medium, specifically, ground connection medium nonlinear degree Bigger, the content of higher hamonic wave is more, and the distortion degree of zero-sequence current is bigger.Therefore, to the zero of singlephase earth fault phase Sequence electric current deployment analysis can recognize different types of ground connection medium.In a kind of method for judging distribution net work earthing fault, By analyzing high resistance ground zero-sequence current wave distortion concavity and convexity, to dry floor tile, wetland brick, wet sand, dry crushing stone, Eight kinds of wet rubble, dry tire and wet tire media carry out identification, classification.However, the zero sequence electricity after ground fault occurs for power distribution network Under the smaller and various noise of the flow valuve scene very big with interference, the concavity and convexity variation of zero-sequence current waveform will be more violent, meeting Cause the accuracy of the above method lower.
In view of this, this application provides a kind of determination methods of the ground connection medium of one-phase earthing failure in electric distribution network, with solution The lower problem of the ground connection medium determining method accuracy of certainly existing distribution net work earthing fault.
Single-phase earthing refers to small electric current grounding system of distribution network single-phase earthing, is the most common failure of distribution system.Distribution Zero sequence current mutual inductor is installed in the line facility of net, it is former when there is a phase electricity that ground connection occurs in the three-phase electricity of distribution network line When barrier, i.e., generation singlephase earth fault when, the phasor of three-phase current and be not equal to zero, at this point, generated electric current in route For zero-sequence current.So zero-sequence current caused by the different corresponding singlephase earth faults occurred of ground connection medium is because of medium The difference of property and it is different.
As shown in FIG. 1, FIG. 1 is a kind of confirmation methods of the ground connection medium of one-phase earthing failure in electric distribution network provided by the present application Step schematic diagram, a kind of determination method of the ground connection medium of one-phase earthing failure in electric distribution network includes the following steps:
S1: when singlephase earth fault occurs for power distribution network, according to the original of the zero-sequence current of one-phase earthing failure in electric distribution network phase Beginning time series carries out phase space reconfiguration to the waveform of zero-sequence current;
S2: the optimum delay time of phase space reconstruction is determined;
S3: the smallest embedding dimension number of phase space reconstruction is determined according to optimum delay time;
S4: the correlation dimension of phase space reconstruction is determined according to smallest embedding dimension number;
S5: the corresponding relationship of the correlation dimension and ground connection medium type that obtain according to correlation dimension and in advance determines single-phase The ground connection medium type of ground fault.
Optionally, according to the original time series x (t) of the zero-sequence current of one-phase earthing failure in electric distribution network phase, to zero sequence electricity The waveform of stream carries out phase space reconfiguration, and determines the delay time of phase space reconstruction, and specific steps include:
S11: according to state x each in original time series x (t)iCorresponding Probability px(xi), the x is calculated according to the following formula (t) comentropy H (x):
S12: according to each state q in the time series q (t) after original time series x (t) delay τjCorresponding probability Pq(qj), the comentropy H (q) of the q (t) is calculated according to the following formula:
Wherein it is possible to understand, q (t)=x (t+ τ);
S13: according to each state x in x (t) and q (t)iAnd qjCorresponding joint probability Pxq(xi,qj), it calculates according to the following formula Conditional entropy H (q | x) of the q (t) for x (t):
Wherein, H (x, q) is combination entropy of the q (t) for x (t), and H (x, q) is according to each state x in x (t) and q (t)iAnd qj Corresponding joint probability Pxq(xi,qj), it is calculated according to the following formula:
S14: according to the I (q, x) obtained by H (q) and H (q | x), determine that first local minizing point is corresponding in I (q, x) Optimum delay time of the τ as phase space reconstruction;
Wherein,
It should be noted that I (q, x) is the mutual information function of q (t) and x (t).
Optionally, the smallest embedding dimension number of phase space reconstruction is determined according to optimum delay time, specific steps include:
S31: according to the point Y of phase space reconstructionu(m), calculating matrix a (u, m) according to the following formula:
Wherein, m is the dimension of phase space reconstruction, Yx(u,m)It (m) is distance Yu(m) nearest point, x (u, m) be greater than 1 and Less than or equal to the integer of N-m τ;
S32: according to the following formula in calculating matrix a (u, m) all elements mean value E (m):
When the value of dimension m is greater than m0, and when the value of E (m) will not change, enable the smallest embedding dimension number mb=m0+1。
Optionally, the correlation dimension of phase space reconstruction is determined according to smallest embedding dimension number, specific steps include:
S41: according to smallest embedding dimension number mb, the point Y (t) in phase space reconstruction is determined:
Y (t)={ y (t), y (t+ τ) ..., y [t+ (mb-1) τ] }, t=1,2 ..., N- (mb-1) τ,
It is understood that mb=m0+ 1, herein, in multidimensional phase space, point is indicated with an ordered series of numbers;
S42: any one point chosen in N number of point that phase space reconstruction includes is as a reference point;
The N-1 point in addition to reference point is calculated to the distance of the reference point, determines to be less than at a distance from reference point and give The point of definite value r is relating dot;
Accounting C of the number of the relating dot in all possible relating dot number N (N-1) is calculated according to the following formulamb (r):
Wherein, Y (i), Y (j) are respectively the ith and jth element in the Y (t), and θ is Heaviside unit function;
S43: according to Cmb(r) with the relationship of the rCalculate the correlation dimension P.
Optionally, lnC is made under smallest embedding dimension numbermb(r)=lnr curve determines the uncalibrated visual servo section of curve, nothing Scale section is linear segments or near-linear section, and uncalibrated visual servo section is fitted to a fitting a straight line, digital simulation straight line Slope, using the slope of fitting a straight line as correlation dimension P.
Optionally, it obtains correlation dimension in advance and is grounded the corresponding relationship of medium type, specific steps include:
S51: the zero-sequence current of the one-phase earthing failure in electric distribution network phase of the known ground connection medium type of measurement, the known ground connection Medium type including at least wet soil, dry earth, wet sand, dry sand ground, wet cement, wet branch and water resistance.It needs to illustrate Be, used in the present embodiment known to this seven kinds be grounded medium type it is only schematical, be not construed as limiting, it is specifically used which A little known ground connection media specifically depend on the circumstances.
S52: according to step S1, the waveform of the zero-sequence current of the singlephase earth fault phase of known ground connection medium type is carried out Phase space reconfiguration.
S53: according to step S11-S12, the optimum delay time of phase space reconstruction is determined.
Specifically, according to step S11-S12 be calculated ground connection medium be respectively wet soil, dry earth, wet sand, dry sand Optimum delay time when ground, wet cement, wet branch and water resistance.
S11: according to state x each in original time series x (t)iCorresponding Probability px(xi), the x is calculated according to the following formula (t) comentropy H (x):
S12: according to each state q in the time series q (t) after original time series x (t) delay τjCorresponding probability Pq(qj), the comentropy H (q) of the q (t) is calculated according to the following formula:
Wherein it is possible to which that understand is q (t)=x (t+ τ);
S13: according to each state x in x (t) and q (t)iAnd qjCorresponding joint probability Pxq(xi,qj), it calculates according to the following formula Conditional entropy H (q | x) of the q (t) for x (t):
Wherein, H (x, q) is combination entropy of the q (t) for x (t), and H (x, q) is according to each state x in x (t) and q (t)iAnd qj Corresponding joint probability Pxq(xi,qj), it is calculated according to the following formula:
S14: according to the I (q, x) obtained by H (q) and H (q | x), the mutual information function I (q, x) of q (t) He x (t), I are determined Optimum delay time of the corresponding τ of first local minizing point as phase space reconstruction in (q, x);
Wherein,
The sample frequency of zero-sequence current is arranged in 20000Hz in the present embodiment, and the frequency of power supply is 50Hz, therefore, zero sequence Have 400 sampled points in each cycle of electric current, when making image, consider delay time bound limitation, take 0 to 200 it Between optimum delay time of the corresponding τ of first more apparent local minizing point as its phase space reconstruction.
Specifically, with reference to Fig. 2 a-2g, Fig. 2 a be grounded medium be wet soil when delay time and mutual information function pass It is curve, Fig. 2 b is the relation curve for being grounded delay time and mutual information function when medium is dry earth, and Fig. 2 c is that ground connection is situated between Matter be wet sand when delay time and mutual information function relation curve, Fig. 2 d is the delay for being grounded medium when being dry sand ground The relation curve of time and mutual information function, Fig. 2 e be grounded medium be wet cement when delay time and mutual information function Relation curve, Fig. 2 f is the relation curve for being grounded delay time and mutual information function of the medium when being wet branch, and Fig. 2 g is to connect The relation curve of delay time and mutual information function when ground medium is water resistance.It is situated between by several ground connection are shown respectively in Fig. 2 a-2g The delay time of matter obtains with the curve of its mutual information function, first local minizing point corresponding delay time in curve 92s, 56s, 68s, 112s, 78s, 50s, 106s respectively, so, ground connection medium be respectively wet soil, dry earth, wet sand, Dry sand ground, wet cement, wet branch and water resistance optimum delay time be respectively 92s, 56s, 68s, 112s, 78s, 50s, 106s.
It should be noted that known ground connection medium type provided by the present embodiment (wet soil, dry earth, wet sand, it is dry Sand ground, wet cement, wet branch and water resistance) real data derive from highlands, real data is only schematical, does not do It is specific to limit.
S54: the best insertion of corresponding each phase space reconstruction is determined according to the optimum delay time of each ground connection medium Dimension;
Specifically, the smallest embedding dimension of the corresponding phase space reconstruction of every kind of ground connection medium is calculated according to S31-S32 Number.
S31: according to the point Y of phase space reconstructionu(m), calculating matrix a (u, m) according to the following formula:
Wherein, m is the dimension of phase space reconstruction, Yx(u,m)It (m) is distance Yu(m) nearest point, x (u, m) be greater than 1 and Less than or equal to the integer of N-m τ;
S32: according to the following formula in calculating matrix a (u, m) all elements mean value E (m):
When the value of dimension m is greater than m0, and when the value of E (m) will not change, enable the smallest embedding dimension number mb=m0+1。
It is respectively that 92s, 56s, 68s, 112s, 78s, 50s, 106s bring E (m) by optimum delay time, what is obtained is best Embedded dimensions are respectively 8,13,10,15,7,11,5.
Specifically, referring to shown in table 1, table 1 is the optimum delay time and most for being grounded medium type and its phase space reconstruction The mapping table of good Embedded dimensions.
Table 1
It is grounded medium type Delay time (s) Smallest embedding dimension number
Wet soil 92 8
Dry earth 56 13
Wet sand 68 10
Dry sand ground 112 15
Wet cement 78 7
Wet branch 50 11
Water resistance 106 5
S55: the correlation dimension of phase space reconstruction is determined according to step S41-S43.
Specifically, S41: smallest embedding dimension number mb, mb=m0+ 1, determine the point Y (t) in phase space reconstruction:
Y (t)=y (t), y (t+ τ) ..., y [t+ (mb-1) τ] }, t=1,2 ..., N- (mb-1) τ;
S42: any one point chosen in N number of point that phase space reconstruction includes is as a reference point;
The N-1 point in addition to reference point is calculated to the distance of the reference point, determines to be less than at a distance from reference point and give The point of definite value r is relating dot;
Accounting C of the relating dot number in all possible relating dot number N (N-1) is calculated according to the following formulamb(r):
Wherein, Y (i), Y (j) are respectively the ith and jth element in the Y (t), and θ is Heaviside unit function;
S43: according to Cmb(r) with the relationship of the rCalculate the correlation dimension P.
Optionally, lnC is made under smallest embedding dimension numbermb(r)=lnr curve determines the uncalibrated visual servo section of curve, nothing Scale section is linear segments or near-linear section, and uncalibrated visual servo section is fitted to a fitting a straight line, digital simulation straight line Slope, correlation dimension P are the slope of fitting a straight line.
S55: obtaining correlation dimension in advance and is grounded the corresponding relationship of medium type.Specifically, referring to Fig. 3 a-3g, Fig. 3 a For ground connection medium be wet soil when smallest embedding dimension number under lnCmb(r)=lnr curve graph, Fig. 3 b are that ground connection medium is dry ground LnC under smallest embedding dimension number when groundmb(r)=lnr curve graph, Fig. 3 c be ground connection medium be wet sand when smallest embedding dimension number Lower lnCmb(r)=lnr curve graph, Fig. 3 d are ground connection medium lnC under smallest embedding dimension number when being dry sand groundmb(r)=lnr Curve graph, Fig. 3 e are ground connection medium lnC under smallest embedding dimension number when being wet cementmb(r)=lnr curve graph, Fig. 3 f are ground connection LnC under smallest embedding dimension number when medium is wet branchmb(r)=lnr curve graph, Fig. 3 g are best when medium is water resistance to be grounded LnC under Embedded dimensionsmb(r)=lnr curve graph.LnC is made under the smallest embedding dimension number of each ground connection medium typemb (r)=lnr curve, by mb=m0+ 1 brings into, and each Embedded dimensions mb corresponds to a curve, and each curve has one section Uncalibrated visual servo section, uncalibrated visual servo section are linear segments or near-linear section, and it is straight that uncalibrated visual servo section is fitted to a fitting Line, the slope of this fitting a straight line are the correlation dimension P of phase space reconstructionn
The calculation formula of correlation dimension is as follows:
Wherein, L indicates rinThe total number of value, n indicate ground connection medium type coding, n=1,2,3,4,5,6,7 difference tables With showing ground connection medium water resistance, wet cement, wet soil, wet sand, the coding of wet branch, dry earth and dry sand ground;
According to known ground connection medium type and pass through the above-mentioned corresponding correlation dimension being calculated, obtains correlation dimension in advance The corresponding relationship of number and ground connection medium type, as shown in table 2, table 2 are the correlation dimension obtained in advance and ground connection medium type Mapping table.
Table 2
It is grounded medium type Correlation dimension (slope of curve)
Wet soil P3=1.2166
Dry earth P6=2.8613
Wet sand P7=1.4489
Dry sand ground P4=3.2101
Wet cement P2=1.1210
Wet branch P5=1.6812
Water resistance P1=1.0298
Optionally, it is calculated, is obtained opposite by step S51-S55 according to the corresponding zero-sequence current of unknown ground connection medium type The correlation dimension for the phase space reconstruction answered.By the correlation dimension of unknown ground connection medium type and the correlation dimension that in advance obtains with The corresponding relationship of ground connection medium type is made comparisons, and determines the ground connection medium type of singlephase earth fault.Correlation dimension and ground connection are situated between The corresponding relationship of matter type, comprising:
Work as P1< P < P2, determine that the ground connection medium type is wet cement;
Work as P2< P < P3, determine the ground connection medium type for wet soil;
Work as P3< P < P4, determine the ground connection medium type for wet sand;
Work as P4< P < P5, determine that the ground connection medium type is wet branch;
Work as P5< P < P6, determine that the ground connection medium type is dry earth;
Work as P6< P < P7, determine that the ground connection medium type is dry sand ground;
As P < P1, determine that the ground connection medium type is water resistance;
Wherein, P is that the corresponding zero-sequence current of unknown ground connection medium passes through the correlation dimension being calculated.
Method provided by the present application, from the angle of the zero-sequence current Wave data of singlephase earth fault phase, using phase Space Reconstruction method analyzes the corresponding zero-sequence current waveform of different ground connection media, according to the optimum delay time of phase space reconstruction Correlation dimension is determined with smallest embedding dimension number, passes through correlation dimension and the correlation dimension and ground connection medium type that in advance obtain Corresponding relationship, determine it is unknown ground connection medium type.Compare the prior art, and this method can more accurately determine single-phase The ground connection medium type of ground fault.
It is required that those skilled in the art can be understood that the technology in the embodiment of the present invention can add by software The mode of general hardware platform realize.Based on this understanding, the technical solution in the embodiment of the present invention substantially or Say that the part that contributes to existing technology can be embodied in the form of software products, which can be with It is stored in a storage medium, such as ROM/RAM, magnetic disk, CD, including some instructions are used so that a computer equipment (can be personal computer, server or the network equipment etc.) executes the certain of each embodiment or embodiment of the invention Method described in part.
Same and similar part may refer to each other between each embodiment in this specification.Especially for embodiment Speech, since it is substantially similar to the method embodiment, so being described relatively simple, related place is referring in embodiment of the method Explanation.

Claims (7)

1. a kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network, which is characterized in that the described method includes:
When singlephase earth fault occurs for power distribution network, according to the original time sequence of the zero-sequence current of one-phase earthing failure in electric distribution network phase Column carry out phase space reconfiguration to the waveform of the zero-sequence current;
Determine the optimum delay time of phase space reconstruction;
The smallest embedding dimension number of the phase space reconstruction is determined according to the optimum delay time;
The correlation dimension of the phase space reconstruction is determined according to the smallest embedding dimension number;
The corresponding relationship of the correlation dimension and ground connection medium type that obtain according to the correlation dimension and in advance, determines described single-phase The ground connection medium type of ground fault.
2. the method according to claim 1, wherein when the optimal delay of the determining phase space reconstruction Between, comprising:
According to state x each in the original time series x (t)iCorresponding Probability px(xi), the x (t) is calculated according to the following formula Comentropy H (x):
According to each state q in the time series q (t) after the original time series x (t) delay τjCorresponding probability Pq (qj), the comentropy H (q) of the q (t) is calculated according to the following formula:
According to each state x in the x (t) and q (t)iAnd qjCorresponding joint probability Pxq(xi,qj), according to the following formula described in calculating Conditional entropy H (q | x) of the q (t) for x (t):
Wherein, H (x, q) is combination entropy of the q (t) for the x (t), and the H (x, q) is according in the x (t) and q (t) Each state xiAnd qjCorresponding joint probability Pxq(xi,qj), it is calculated according to the following formula:
According to the I (q, x) obtained by the H (q) and the H (q | x), determine that first local minizing point is corresponding in I (q, x) Optimum delay time of the τ as the phase space reconstruction;
Wherein,
3. according to the method described in claim 2, it is characterized in that, described determine that the reconstruct is mutually empty according to optimum delay time Between smallest embedding dimension number, comprising:
According to the point Y of the phase space reconstructionu(m), calculating matrix a (u, m) according to the following formula:
Wherein, m is the dimension of the phase space reconstruction, Yx(u,m)It (m) is distance Yu(m) nearest point, x (u, m) are greater than 1 and small In the integer for being equal to N-m τ;
According to the following formula in calculating matrix a (u, m) all elements mean value E (m):
When the value of the dimension m is greater than m0, and when the value of E (m) will not change, enable the smallest embedding dimension number mb=m0+1。
4. according to the method described in claim 3, it is characterized in that, described determine that the reconstruct is mutually empty according to smallest embedding dimension number Between correlation dimension, include:
According to the smallest embedding dimension number mb, the point Y (t) in the phase space reconstruction is determined:
Y (t)=y (t), y (t+ τ) ..., y [t+ (mb-1) τ] }, t=1,2 ..., N- (mb-1) τ;
Any one point chosen in N number of point that the phase space reconstruction includes is as a reference point;
The N-1 point in addition to reference point is calculated to the distance of the reference point, determines to be less than at a distance from the reference point and give The point of definite value r is relating dot;
Accounting C of the number of the relating dot in all possible relating dot number N (N-1) is calculated according to the following formulamb(r):
Wherein, Y (i), Y (j) are respectively the ith and jth element in the Y (t), and θ is Heaviside unit function;
According to the Cmb(r) with the relationship of the rCalculate the correlation dimension P.
5. according to the method described in claim 4, it is characterized in that, the calculating correlation dimension P includes:
LnC is made at the smallest embedding dimension number mbmb(r)=lnr curve confirms the uncalibrated visual servo section of the curve, institute Stating uncalibrated visual servo section is linear segments or near-linear section, and the uncalibrated visual servo section is fitted to a fitting a straight line, calculates institute The slope for stating fitting a straight line, using the slope of the fitting a straight line as the correlation dimension P.
6. according to the method described in claim 5, it is characterized in that, as steps described below, obtaining correlation dimension and ground connection in advance The corresponding relationship of medium type, comprising:
The zero-sequence current that the one-phase earthing failure in electric distribution network phase of medium is grounded known to every kind, the known ground connection medium are measured respectively Including at least wet soil, dry earth, wet sand, dry sand ground, wet cement, wet branch and water resistance;
According to the original time series of the zero-sequence current, phase space reconfiguration is carried out to the waveform of the zero-sequence current;
Determine the optimum delay time of phase space reconstruction;
The smallest embedding dimension number of the phase space reconstruction is determined according to the optimum delay time;
The correlation dimension P of the phase space reconstruction is determined according to the smallest embedding dimension numbern:
Wherein, L indicates rinThe total number of value, n indicate ground connection medium type coding, and n=1,2,3,4,5,6,7 respectively indicate and connect Ground medium water resistance, wet cement, wet soil, wet sand, the coding of wet branch, dry earth and dry sand ground;
According to the type of known ground connection medium and the correlation dimension, it is corresponding with ground connection medium type that correlation dimension is obtained in advance Relationship.
7. according to the method described in claim 6, it is characterized in that, the corresponding pass of the correlation dimension and ground connection medium type System, comprising:
Work as P1< P < P2, determine that the ground connection medium type is wet cement;
Work as P2< P < P3, determine the ground connection medium type for wet soil;
Work as P3< P < P4, determine the ground connection medium type for wet sand;
Work as P4< P < P5, determine that the ground connection medium type is wet branch;
Work as P5< P < P6, determine that the ground connection medium type is dry earth;
Work as P6< P < P7, determine that the ground connection medium type is dry sand ground;
As P < P1, determine that the ground connection medium type is water resistance;
Wherein, P is that the corresponding zero-sequence current of unknown ground connection medium passes through the correlation dimension being calculated.
CN201910557993.5A 2019-06-26 2019-06-26 A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network Pending CN110187241A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910557993.5A CN110187241A (en) 2019-06-26 2019-06-26 A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910557993.5A CN110187241A (en) 2019-06-26 2019-06-26 A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network

Publications (1)

Publication Number Publication Date
CN110187241A true CN110187241A (en) 2019-08-30

Family

ID=67723332

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910557993.5A Pending CN110187241A (en) 2019-06-26 2019-06-26 A kind of determination method of the ground connection medium type of one-phase earthing failure in electric distribution network

Country Status (1)

Country Link
CN (1) CN110187241A (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101793907A (en) * 2010-02-05 2010-08-04 浙江大学 Short-term wind speed forecasting method of wind farm
CN102110244A (en) * 2011-02-25 2011-06-29 杭州电子科技大学 Correlation-dimension-based neuron action potential feature extraction method
CN103197201A (en) * 2013-03-07 2013-07-10 福建省电力有限公司 Low-resistance, medium-resistance and high-resistance grounding fault type recognition method of power transmission line
CN103529316A (en) * 2013-08-15 2014-01-22 国家电网公司 Comprehensive detection method for high resistance ground faults of electric power system
CN107085164A (en) * 2017-03-22 2017-08-22 清华大学 A kind of electric network fault type determines method and device
CN108646149A (en) * 2018-04-28 2018-10-12 国网江苏省电力有限公司苏州供电分公司 Fault electric arc recognition methods based on current characteristic extraction

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101793907A (en) * 2010-02-05 2010-08-04 浙江大学 Short-term wind speed forecasting method of wind farm
CN102110244A (en) * 2011-02-25 2011-06-29 杭州电子科技大学 Correlation-dimension-based neuron action potential feature extraction method
CN103197201A (en) * 2013-03-07 2013-07-10 福建省电力有限公司 Low-resistance, medium-resistance and high-resistance grounding fault type recognition method of power transmission line
CN103529316A (en) * 2013-08-15 2014-01-22 国家电网公司 Comprehensive detection method for high resistance ground faults of electric power system
CN107085164A (en) * 2017-03-22 2017-08-22 清华大学 A kind of electric network fault type determines method and device
CN108646149A (en) * 2018-04-28 2018-10-12 国网江苏省电力有限公司苏州供电分公司 Fault electric arc recognition methods based on current characteristic extraction

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
詹启帆 等: "配电网高阻接地故障检测技术综述", 《电气技术》 *

Similar Documents

Publication Publication Date Title
Peppanen et al. Leveraging AMI data for distribution system model calibration and situational awareness
Mora-Florez et al. Comparison of impedance based fault location methods for power distribution systems
Zhang et al. Diagnosis of breaks in substation's grounding grid by using the electromagnetic method
Bakar et al. High impedance fault location in 11 kV underground distribution systems using wavelet transforms
Pereira et al. Improved fault location on distribution feeders based on matching during-fault voltage sags
Dawalibi et al. Earth resistivity measurement interpretation techniques
EP0307826B1 (en) Protection device for high resistance ground faults
TWI461707B (en) Earth ground tester with remote control
Saha et al. Fault location on power networks
Mohsenian-Rad et al. Distribution synchrophasors: Pairing big data with analytics to create actionable information
Chang et al. An improved backward/forward sweep load flow algorithm for radial distribution systems
Salim et al. Hybrid fault diagnosis scheme implementation for power distribution systems automation
Tayjasanant et al. A resistance sign-based method for voltage sag source detection
Huang et al. High-impedance fault detection utilizing a Morlet wavelet transform approach
Micu et al. AC interference on pipelines due to double circuit power lines: A detailed study
CN103187804B (en) Station area electricity utilization monitoring method based on bad electric quantity data identification
US6996483B2 (en) System and method for locating a disturbance in a power system based upon disturbance power and energy
Abur et al. Power system state estimation: theory and implementation
Islam Detection of shorted turns and winding movements in large power transformers using frequency response analysis
KR100473798B1 (en) Method for detecting line to ground fault location for power systems
Jamali et al. A new fault location method for distribution networks using sparse measurements
US10338127B2 (en) Method and system for identifying full parameters of element by fault recording and fault locating method
Tawfik et al. ANN-based techniques for estimating fault location on transmission lines using Prony method
You et al. Disturbance location determination based on electromechanical wave propagation in FNET/GridEye: a distribution-level wide-area measurement system
CN1070612C (en) Method of locating a single-phase ground fault in a power distribution network

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