CN113917279B - Power distribution network fault phase distinguishing method and system and fault line distinguishing method and system - Google Patents
Power distribution network fault phase distinguishing method and system and fault line distinguishing method and system Download PDFInfo
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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
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
Abstract
The invention discloses a method and a system for judging a fault phase of a power distribution network, and a method and a system for judging a fault line.
Description
Technical Field
The invention relates to a method and a system for distinguishing fault phases of a power distribution network and a method and a system for distinguishing fault lines, and belongs to the technical field of power distribution automation.
Background
At present, the fault phase distinguishing method of the power distribution network is mainly divided into two types according to different electrical quantity information: one is a fault phase discrimination method based on fault phase voltage steady state information; the other is a fault phase discrimination method based on the fault phase current transient quantity; the first method is influenced by a neutral point grounding mode and a steady state quantity selection moment; the second method has the advantages of overlarge calculated amount, low judging speed and risk of misjudgment or missed judgment, and is rarely applied to actual engineering; therefore, a new method for distinguishing the fault phases of the power distribution network is urgently needed.
Disclosure of Invention
The invention provides a method, a system, a storage medium and computing equipment for discriminating a fault phase of a power distribution network, and solves the problems disclosed in the background art.
In order to solve the technical problems, the invention adopts the following technical scheme:
The fault phase distinguishing method of the power distribution network comprises the following steps:
Determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
Taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
and judging the ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and the first preset rule.
The method further comprises the step of judging whether single-phase earth fault occurs or not, and the step comprises the following steps:
according to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
And if any phase current variation is larger than the threshold value, judging that the single-phase earth fault occurs.
In response to determining that a single-phase-to-earth fault occurred, determining an occurrence time of the single-phase-to-earth fault includes:
Responding to the judgment that single-phase earth fault occurs, and acquiring three-phase current variation in a preset time window before and after the time t 0; wherein, the time t 0 is the time when the single-phase earth fault is judged to occur;
sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value;
and determining the occurrence time of the single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule.
The second preset rule is:
if the sampling point n meets |delta I max,n+m|＞Ks|ΔImax,n |, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
The formula for calculating the three-phase current energy is as follows:
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, n is a sampling point corresponding to the starting moment, n+Deltan is a sampling zero crossing point corresponding to the stopping moment, n is not less than x and not more than n+Deltan, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>And normalizing the C-phase current variation corresponding to the sampling point x.
The formula for extracting the three-phase differential component and the three-phase braking component in the three-phase current fault component is as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is an a-phase braking component, i rb is a B-phase braking component, and i rc is a C-phase braking component.
The first preset rule is:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
A power distribution network fault phase discrimination system comprising:
a time determining module: determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
The fault component acquisition module: taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
An energy component acquisition module: according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
the ground fault phase distinguishing module distinguishes the ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and the first preset rule.
The first preset rule is:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
The power distribution network fault line distinguishing method comprises the following steps:
Determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
Taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
and judging the ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule.
The method further comprises the step of judging whether single-phase earth fault occurs or not, and the step comprises the following steps:
according to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
And if any phase current variation is larger than the threshold value, judging that the single-phase earth fault occurs.
In response to determining that a single-phase-to-earth fault occurred, determining an occurrence time of the single-phase-to-earth fault includes:
Responding to the judgment of single-phase earth fault, and acquiring three-phase current variation in a preset time window before and after the time t 0; wherein, the time t 0 is the time when the single-phase earth fault is judged to occur;
sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value;
and determining the occurrence time of the single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule.
The second preset rule is:
if the sampling point n meets |delta I max,n+m|＞Ks|ΔImax,n |, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
The formula for calculating the three-phase current energy is as follows:
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, n is a sampling point corresponding to the starting moment, n+Deltan is a sampling zero crossing point corresponding to the stopping moment, n is not less than x and not more than n+Deltan, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>And normalizing the C-phase current variation corresponding to the sampling point x.
The formula for extracting the three-phase differential component and the three-phase braking component in the three-phase current fault component is as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is an a-phase braking component, i rb is a B-phase braking component, and i rc is a C-phase braking component.
The third preset rule is:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
A power distribution network fault line discrimination system comprising:
a time determining module: determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
The fault component acquisition module: taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
An energy component acquisition module: according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
The ground fault line distinguishing module: and judging the ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule.
The third preset rule is:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
A computer readable storage medium storing one or more programs, characterized by: the one or more programs include instructions, which when executed by a computing device, cause the computing device to perform a power distribution network fault phase discrimination method, or a power distribution network fault line discrimination.
The invention has the beneficial effects that: when a single-phase earth fault occurs, the three-phase current fault component is extracted, the earth fault phase is judged by calculating the three-phase current energy and extracting the differential and braking components in the fault component, and the transient phase current fault component is adopted, so that only the information of the initial phase of the fault is needed, the influence of a neutral point earth mode and a steady state quantity selecting moment is avoided, the judging speed is high, and the accuracy is high.
Drawings
FIG. 1 is a block diagram of a power distribution network system;
FIG. 2 is a flow chart of a method for discriminating a fault phase of a power distribution network;
Fig. 3 is a flowchart of a method for discriminating a faulty line of a power distribution network.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
As shown in fig. 1, when the system is in normal operation, the low-voltage side three-phase current difference of the bus transformer is mainly influenced by the three-phase imbalance of the system and is in a non-fault characteristic; when a single-phase earth fault occurs in the system, the low-voltage side non-fault phase current of the bus transformer is mainly the non-fault line capacitance current, and the fault phase current is mainly the sum of the non-fault phase capacitance currents, but the directions are opposite, and the fault phase is distinguished by utilizing the difference characteristic of the fault phase and the non-fault phase.
Based on the principle, the fault phase distinguishing method of the power distribution network shown in fig. 2 is constructed, and comprises the following steps:
Step 1, determining occurrence time of single-phase grounding faults in response to judgment of occurrence of single-phase grounding faults;
step 2, taking the single-phase earth fault occurrence time as an initial time and the time corresponding to the next sampling zero-crossing point as a cut-off time, and acquiring a three-phase current fault component of the low-voltage side of the bus transformer between the initial time and the cut-off time;
step 3, calculating three-phase current energy according to the three-phase current fault components, and extracting three-phase differential components and three-phase braking components in the three-phase current fault components;
and 4, judging the ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and the first preset rule.
The method can be arranged in a detection module at the head end of a line, extracts three-phase current fault components when single-phase grounding faults occur, and judges the grounding fault phase by calculating three-phase current energy and extracting differential and braking components in the fault components.
Before judging whether single-phase earth fault occurs, judging whether the phase current amplitude is larger than a threshold value, if not, indicating that the phase current change is possibly caused by load switching and the like, and if so, judging whether the single-phase earth fault occurs according to the real-time change quantity of the three-phase current, wherein the method comprises the following steps:
11 According to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
the sampled three-phase currents need to be real-time and synchronous, namely, the three-phase currents at the low voltage side of the busbar transformer are synchronously sampled in real time, and the three-phase current variation is calculated according to the following formula:
Δiph(t)＝iph(t)-iph(t-N×ΔT)
Wherein Δi ph (T) is the current time T phase current variation (referred to as "phase current sampling value variation") i ph (T) is the current time T phase current sampling value, Δt is the sampling interval time, and N is the number of sampling points in the power frequency period.
12 If any phase current variation is larger than the threshold value, judging that single-phase earth fault occurs, otherwise, judging that single-phase earth fault does not occur, and switching to 11).
If judging that single-phase grounding faults occur, formally starting fault phase discrimination, and determining the occurrence time of the single-phase grounding faults can be realized by the following steps/methods:
21 Acquiring three-phase current variation in a preset time window before and after the time t 0;
the time t 0 is the time when the single-phase earth fault is judged to occur, and is also the fault phase judging starting time;
The preset time window is generally set to 1 cycle, that is, three-phase current variation [ delta i ph(t0)-N,Δiph(t0) +N ] in each cycle before and after the time t 0 is obtained.
22 Sequentially sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value according to the sequenced phase current variation; the effective value is the effective value of the sequence, namely the square sum root opening value of the three-phase current variation;
the phase current variation after the sequence is as follows:
23 Determining occurrence time of single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule;
the second preset rule is:
if the sampling point n meets |delta I max,n+m|＞Ks|ΔImax,n |, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
And after the time corresponding to the sampling point n is determined to be the occurrence time of the single-phase earth fault, extracting the three-phase current fault components after the occurrence time.
Firstly, determining the next sampling positive sequence zero crossing point n+delta n according to the occurrence time, namely determining the cut-off time, and acquiring a phase current fault component of a low-voltage side of a bus transformer between the start time and the cut-off time, wherein the phase current fault component is a data set processed by continuous sampling values and is transient data, and the method specifically comprises the following steps:
Phase A: { Δi A(n),ΔiA(n+1),ΔiA(n+2)…ΔiA (n+Δn) }
And B phase: { Δi B(n),ΔiB(n+1),ΔiB(n+2)…ΔiB (n+Δn) }
And C phase: { Δi C(n),ΔiC(n+1),ΔiC(n+2)…ΔiC (n+Δn) }
Normalizing the obtained phase current fault components:
wherein, For the phase current variation normalization value corresponding to the sampling point x, Δi ph (x) is the phase current variation corresponding to the sampling point x.
Based on the normalized values, three-phase current energy can be calculated, and three-phase differential components and three-phase braking components in three-phase current fault components are extracted, wherein the specific formula can be as follows:
The three-phase current energy is calculated as follows:
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, n is a sampling point corresponding to the starting moment, n+Deltan is a sampling zero crossing point corresponding to the stopping moment, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>And normalizing the C-phase current variation corresponding to the sampling point x.
Extracting three-phase differential components and three-phase braking components in three-phase current fault components:
Wherein i da is a phase difference component, i db is a phase difference component, and i dc is a phase difference component;
Wherein i ra is an a-phase braking component, i rb is a B-phase braking component, and i rc is a C-phase braking component.
Judging a ground fault phase according to three-phase current energy, three-phase differential components, three-phase braking components and a first preset rule, wherein the first preset rule can be as follows:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Where k set1 is a sequence component fault feature reliability coefficient and k set2 is a phase current fault change coefficient.
The software system corresponding to the method, namely the power distribution network fault phase discrimination system, comprises the following components:
A time determining module: in response to determining that the single-phase-to-ground fault occurred, determining a time of occurrence of the single-phase-to-ground fault.
The fault component acquisition module: and taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time.
An energy component acquisition module: and calculating three-phase current energy according to the three-phase current fault components, and extracting three-phase differential components and three-phase braking components in the three-phase current fault components.
The ground fault phase judging module judges the ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a first preset rule;
the first preset rule is:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
If the detection modules of the method are configured at the head ends of the lines, the fault line discrimination can be further realized, namely, the discrimination of the bus grounding fault and the phase line grounding fault, specifically as shown in fig. 3, the power distribution network fault line discrimination method comprises the following steps:
S1) determining occurrence time of single-phase grounding faults in response to judgment of occurrence of single-phase grounding faults;
S2) taking the single-phase earth fault occurrence time as an initial time and the time corresponding to the next sampling zero-crossing point as a cut-off time, and acquiring a phase current fault component of the low-voltage side of the bus transformer between the initial time and the cut-off time;
S3) calculating three-phase current energy according to the three-phase current fault components, and extracting three-phase differential components and three-phase braking components in the three-phase current fault components;
S4) judging the ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule.
Before judging whether single-phase earth fault occurs, judging whether the phase current amplitude is larger than a threshold value, if not, indicating that the phase current change is possibly caused by load switching and the like, and if so, judging whether the single-phase earth fault occurs according to the real-time change quantity of the three-phase current, wherein the method comprises the following steps:
11 According to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
the sampled three-phase currents need to be real-time and synchronous, namely, the three-phase currents at the low voltage side of the busbar transformer are synchronously sampled in real time, and the three-phase current variation is calculated according to the following formula:
Δiph(t)＝iph(t)-iph(t-N×ΔT)
Wherein Δi ph (T) is the current time T phase current variation (referred to as "phase current sampling value variation") i ph (T) is the current time T phase current sampling value, Δt is the sampling interval time, and N is the number of sampling points in the power frequency period.
12 If any phase current variation is larger than the threshold value, judging that single-phase earth fault occurs, otherwise, judging that single-phase earth fault does not occur, and switching to 11).
If judging that single-phase grounding faults occur, formally starting fault phase discrimination, and determining the occurrence time of the single-phase grounding faults can be realized by the following steps/methods:
21 Acquiring three-phase current variation in a preset time window before and after the time t 0;
the time t 0 is the time when the single-phase earth fault is judged to occur, and is also the fault phase judging starting time;
The preset time window is generally set to 1 cycle, that is, three-phase current variation [ delta i ph(t0)-N,Δiph(t0) +N ] in each cycle before and after the time t 0 is obtained.
22 Sequentially sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value according to the sequenced phase current variation;
the phase current variation after the sequence is as follows:
23 Determining occurrence time of single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule;
the second preset rule is:
if the sampling point n meets |delta I max,n+m|＞Ks|ΔImax,n |, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
And after the time corresponding to the sampling point n is determined to be the occurrence time of the single-phase earth fault, extracting the three-phase current fault components after the occurrence time.
Firstly, determining the next sampling positive sequence zero crossing point n+delta n according to the occurrence time, namely determining the cut-off time, and acquiring the phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time, wherein the phase current fault component can be specifically as follows:
Phase A: { Δi A(n),ΔiA(n+1),ΔiA(n+2)…ΔiA (n+Δn) }
And B phase: { Δi B(n),ΔiB(n+1),ΔiB(n+2)…ΔiB (n+Δn) }
And C phase: { Δi C(n),ΔiC(n+1),ΔiC(n+2)…ΔiC (n+Δn) }
Normalizing the obtained phase current fault components:
wherein, For the phase current variation normalization value corresponding to the sampling point x, Δi ph (x) is the phase current variation corresponding to the sampling point x.
Based on the normalized values, three-phase current energy can be calculated, and three-phase differential components and three-phase braking components in three-phase current fault components are extracted, wherein the specific formula can be as follows:
The three-phase current energy is calculated as follows:
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, n is a sampling point corresponding to the starting moment, n+Deltan is a sampling zero crossing point corresponding to the stopping moment, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>And normalizing the C-phase current variation corresponding to the sampling point x.
Extracting three-phase differential components and three-phase braking components in three-phase current fault components:
Wherein i da is a phase difference component, i db is a phase difference component, and i dc is a phase difference component;
Wherein i ra is an a-phase braking component, i rb is a B-phase braking component, and i rc is a C-phase braking component.
Judging a ground fault line according to three-phase current energy, three-phase differential components, three-phase braking components and a third preset rule, wherein the third preset rule is as follows:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Where k set1 is a sequence component fault feature reliability coefficient and k set2 is a phase current fault change coefficient.
The software system corresponding to the method, namely the power distribution network fault line distinguishing system, comprises the following components:
A time determining module: in response to determining that the single-phase-to-ground fault occurred, determining a time of occurrence of the single-phase-to-ground fault.
The fault component acquisition module: and taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time.
An energy component acquisition module: and calculating three-phase current energy according to the three-phase current fault components, and extracting three-phase differential components and three-phase braking components in the three-phase current fault components.
The ground fault line distinguishing module: judging a ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule;
the third preset rule is:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, i rc is a phase C braking component, i da is a phase A differential component, i db is a phase B differential component, i dc is a phase C differential component, E A is a phase A current energy, E B is a phase B current energy, E C is a phase C current energy, k set1 is a sequence component fault characteristic reliability coefficient, and k set2 is a phase current fault change coefficient.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform a power distribution network fault phase discrimination method or a power distribution network fault line discrimination method.
A computing device comprising one or more processors, one or more memories, and one or more programs, wherein one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing a distribution network fault phase discrimination method or a distribution network fault line discrimination method.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof, but rather as providing for the use of additional embodiments and advantages of all such modifications, equivalents, improvements and similar to the present invention are intended to be included within the scope of the present invention as defined by the appended claims.
Claims (13)
1. The power distribution network fault phase distinguishing method is characterized by comprising the following steps of:
Determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
Taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
The formulas of the three-phase differential component and the three-phase braking component in the three-phase current fault component are as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, and i rc is a phase C braking component;
Judging a ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and the first preset rule; the first preset rule is as follows:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, k set1 is sequence component fault characteristic reliable coefficient, and k set2 is phase current fault change coefficient.
2. The method for distinguishing fault phases of a power distribution network according to claim 1, further comprising a step of judging whether a single-phase earth fault occurs, the step comprising:
according to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
And if any phase current variation is larger than the threshold value, judging that the single-phase earth fault occurs.
3. The method according to claim 2, wherein determining the occurrence time of the single-phase earth fault in response to determining that the single-phase earth fault occurs comprises:
Responding to the judgment of single-phase earth fault, and acquiring three-phase current variation in a preset time window before and after the time t 0; wherein, the time t 0 is the time when the single-phase earth fault is judged to occur;
sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value;
and determining the occurrence time of the single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule.
4. A method of distinguishing a faulty phase of a power distribution network according to claim 3, wherein the second preset rule is:
If the sampling point n meets delta I max,n+m＞KsΔImax,n, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
5. The method for distinguishing a fault phase of a power distribution network according to claim 1, wherein the formula for calculating the energy of three-phase current is:
6. the utility model provides a distribution network fault phase discrimination system which characterized in that includes:
a time determining module: determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
The fault component acquisition module: taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
An energy component acquisition module: according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
The formulas of the three-phase differential component and the three-phase braking component in the three-phase current fault component are as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, and i rc is a phase C braking component;
the ground fault phase judging module judges the ground fault phase according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a first preset rule; the first preset rule is as follows:
If it is E a＞Ebkset2、Eb≈Ec and E a＞Eckset2, then phase a is the ground fault phase;
If it is E b＞Eakset2、Ec≈Ea and E b＞Eckset2, then B phase earth fault phase;
If it is E a≈Eb、Ec＞Eakset2 and E c＞Ebkset2, then C is connected to the earth fault phase;
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, k set1 is sequence component fault characteristic reliable coefficient, and k set2 is phase current fault change coefficient.
7. The power distribution network fault line distinguishing method is characterized by comprising the following steps of:
Determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
Taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
The formulas of the three-phase differential component and the three-phase braking component in the three-phase current fault component are as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, and i rc is a phase C braking component;
Judging a ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule; the third preset rule is as follows:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, k set1 is sequence component fault characteristic reliable coefficient, and k set2 is phase current fault change coefficient.
8. The power distribution network fault line discrimination method according to claim 7, further comprising a step of judging whether a single-phase earth fault has occurred, the step comprising:
according to the sampled low-voltage side three-phase current of the bus transformer, calculating the three-phase current variation;
And if any phase current variation is larger than the threshold value, judging that the single-phase earth fault occurs.
9. The power distribution network fault line discrimination method according to claim 8, wherein determining an occurrence timing of the single-phase-to-ground fault in response to determining that the single-phase-to-ground fault has occurred, comprises:
Responding to the judgment of single-phase earth fault, and acquiring three-phase current variation in a preset time window before and after the time t 0; wherein, the time t 0 is the time when the single-phase earth fault is judged to occur;
sequencing the obtained three-phase current variation, and screening out the phase with the largest effective value;
and determining the occurrence time of the single-phase grounding fault according to the current variation of the maximum phase of the effective value and a second preset rule.
10. The method for distinguishing a faulty line of a power distribution network according to claim 9, wherein the second preset rule is:
If the sampling point n meets delta I max,n+m＞KsΔImax,n, the time corresponding to the sampling point is the occurrence time of single-phase grounding faults;
Wherein K s is the singular value change rate, deltaI max,n+m is the maximum phase current change amount of the effective value corresponding to the sampling point n+m, m is the continuous change point number required for judging the occurrence time of the single-phase earth fault as the corresponding time of the sampling point n, and DeltaI max,n is the maximum phase current change amount of the effective value corresponding to the sampling point n.
11. The method for distinguishing power distribution network fault line according to claim 7, wherein the formula for calculating three-phase current energy is:
12. the utility model provides a distribution network fault line discrimination system which characterized in that includes:
a time determining module: determining the occurrence time of the single-phase earth fault in response to judging that the single-phase earth fault occurs;
The fault component acquisition module: taking the occurrence time of the single-phase earth fault as the starting time and the corresponding time of the next sampling zero crossing as the cut-off time, and acquiring the three-phase current fault component of the low-voltage side of the bus transformer between the starting time and the cut-off time;
An energy component acquisition module: according to the three-phase current fault components, three-phase current energy is calculated, and three-phase differential components and three-phase braking components in the three-phase current fault components are extracted;
The formulas of the three-phase differential component and the three-phase braking component in the three-phase current fault component are as follows:
Wherein i da is a phase difference component, i db is a phase difference component, i dc is a phase difference component, n is a sampling point corresponding to the starting moment, n+Δn is a sampling zero-crossing point corresponding to the stopping moment, n is not less than x and not more than n+Δn, Normalized value of A phase current variation corresponding to sampling point x,/>Normalized value of B-phase current variation corresponding to sampling point x,/>The normalized value of the C-phase current variation corresponding to the sampling point x;
Wherein i ra is a phase A braking component, i rb is a phase B braking component, and i rc is a phase C braking component;
the ground fault line distinguishing module: judging a ground fault line according to the three-phase current energy, the three-phase differential component, the three-phase braking component and a third preset rule; the third preset rule is as follows:
If the phase line meets the corresponding fault characteristics, the phase line is grounded;
if the three-phase lines all meet the non-fault characteristics, the bus is grounded;
wherein,
The fault characteristics are as follows:
the characteristics of the a-phase fault, Ea＞Ebkset2、/>Eb≈Ec、/>And E a＞Eckset2;
the characteristics of the B-phase fault, Ec≈Ea、/>Eb＞Eakset2、/>And E b＞Eckset2;
the characteristics of the failure of the C-phase, Ea≈Eb、/>Ec＞Ebkset2、/>And E c＞Eakset2;
The non-fault features are:
Ea≈Eb、/>Eb≈Ec、/> and E a≈Ec;
Wherein E A is A phase current energy, E B is B phase current energy, E C is C phase current energy, k set1 is sequence component fault characteristic reliable coefficient, and k set2 is phase current fault change coefficient.
13. A computer readable storage medium storing one or more programs, characterized by: the one or more programs include instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-5, or 7-11.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103579999A (en) * | 2012-07-30 | 2014-02-12 | 国电南瑞科技股份有限公司 | High-sampling-rate method for sampling value differential protection of multi-section type self-adaption transformer |
| CN109444644A (en) * | 2018-12-21 | 2019-03-08 | 南京国电南自电网自动化有限公司 | Based on the differential wire selection method for power distribution network single phase earthing failure of transient |
| CN112240966A (en) * | 2020-08-06 | 2021-01-19 | 许继集团有限公司 | Fault current grounding judgment method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10794945B2 (en) * | 2015-09-09 | 2020-10-06 | Beijing Inhand Networks Technology Co., Ltd. | Method for detecting and locating single-phase ground fault on low current grounded power-distribution network |
| CN109275337A (en) * | 2016-06-14 | 2019-01-25 | 施瓦哲工程实验有限公司 | The mutually selection of traveling wave fault detection system |
-
2021
- 2021-09-24 CN CN202111119835.5A patent/CN113917279B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103579999A (en) * | 2012-07-30 | 2014-02-12 | 国电南瑞科技股份有限公司 | High-sampling-rate method for sampling value differential protection of multi-section type self-adaption transformer |
| CN109444644A (en) * | 2018-12-21 | 2019-03-08 | 南京国电南自电网自动化有限公司 | Based on the differential wire selection method for power distribution network single phase earthing failure of transient |
| CN112240966A (en) * | 2020-08-06 | 2021-01-19 | 许继集团有限公司 | Fault current grounding judgment method |
Non-Patent Citations (2)
| Title |
|---|
| 基于电流分布系数的母差保护非故障相饱和判别;王风光等;电力工程技术;20200928(第05期);全文 * |
| 直流馈入下交流系统故障特性分析及故障分量电流差动保护改进;杨子荷等;电力自动化设备;20190930;第39卷(第9期);全文 * |
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