CN114859166A - Novel power system fault positioning and isolating method and system - Google Patents
Novel power system fault positioning and isolating 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
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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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
- G01R31/088—Aspects of digital computing
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- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention provides a novel method and a system for positioning and isolating short-circuit faults of a power system based on edge calculation, wherein the method comprises the following steps: the edge calculation unit, the switch control terminals distributed in the whole network and the current electric field sensors distributed in the whole network; the edge computing unit is provided with a short-circuit fault positioning algorithm module and a short-circuit fault isolation strategy module, divides the switch control terminal into different protection sections according to the topological structure of the power distribution network, and divides the current electric field sensor into different positioning sections; the method comprises the steps that a switch control terminal collects three-phase current waveforms of a distribution line in real time; the current electric field sensor acquires three-phase current and three-phase electric field waveforms of the distribution line in real time; when a short-circuit fault occurs, the edge computing unit collects fault information of the switch control terminal and the current electric field sensor and short-circuit fault time, and calls current and electric field waveform data of the whole network terminal at the short-circuit time. The technical problems of poor compatibility and low fault positioning precision are solved.
Description
Technical Field
The invention relates to the technical field of power distribution network fault location and fault isolation, in particular to a novel power system short-circuit fault location and isolation system and method under the distributed energy access condition.
Background
With the large-scale intermittent new energy grid-connected power generation, the active power distribution network plays an important role in the aspects of utilizing renewable energy and improving the power utilization reliability of users. When the active power distribution network has a short-circuit fault, the distributed power supply injects short-circuit current to a fault point, so that the short-circuit current flows through a switch at the downstream of the fault point. If the short-circuit current provided by the distributed power supply exceeds the overcurrent detection setting value, the traditional short-circuit fault positioning isolation and fault recovery method fails.
The invention patent with the application number of CN201910857616.3 discloses a fault location and isolation method for a flexible direct current distribution network, which is a full-bridge submodule (FBMMC) flexible direct current distribution network fault location and isolation method based on the current zero-crossing detection principle. The method is characterized in that the quick isolation of the fault line is realized by a mechanical switch marked as that the current at two ends of the line does not simultaneously pass through zero, and the fault area is judged by the communication at the two ends of the line. The full-bridge submodule type (FBMMC) flexible direct current distribution network fault location and isolation technology adopted by the county has the advantages that the logic is different from the power grid fault location realization technology, the processed signal types are obviously different, and meanwhile, the fault location and isolation technology applied to the flexible direct current distribution network is different from the application scene of the county. At present, a plurality of research units at home and abroad develop related research works in the field of active power distribution network fault location, and the proposed scheme mainly comprises the following steps:
(1) the method for locating the fault feeder line by using the current amplitude is found by comparing the short-circuit current flowing through two sides of the feeder line according to the fault current characteristic of the DG and the amplitude difference characteristic of the current at two ends of a non-fault section and a fault section when the DG is merged into the power distribution network when a fault occurs in the feeder line of the active power distribution network.
(2) The difference of current phase angles at two ends of a fault feeder line section and a non-fault feeder line section when a fault occurs in an active power distribution network constructs a current phase angle difference criterion to locate the fault section, but the scheme does not consider the change of a DG output current phase angle when the fault occurs.
(3) The fault current direction comparison method has clear criterion and high reliability, but needs to install a voltage transformer or a sensor at a switch to measure voltage, and many section switches usually only measure current signals due to the reasons of installation space, cost and the like.
In conclusion, the prior art has the technical problems of poor compatibility and low fault positioning precision.
Disclosure of Invention
The technical problem to be solved by the invention is how to solve the technical problems of poor compatibility and low fault positioning precision in the prior art.
The invention adopts the following technical scheme to solve the technical problems: a novel power system fault positioning and isolating method comprises the following steps:
s1, acquiring real-time line current electric field data;
s2, processing the real-time line current electric field data to obtain short-circuit fault information, and obtaining wave recording waveform data according to the short-circuit fault information;
s3, transmitting the short-circuit fault information and the wave recording waveform data to an edge calculation unit;
s4, obtaining the line topology with the following logic:
G＝(V,E)
V＝V 0 ,V 1 ,V 2 ,…V n
F＝F 0 ,F 1 ,…F p |F∈V
S＝S 0 ,S 1 ,…S q |S∈V
E＝{(V i ,V j )|V i ,V j ∈V}i,j＝0,1,…n
in the formula, a distributed switch control terminal and a current electric field sensor form a node V of the line topology, F is a distributed switch terminal node, S is a distributed current electric field sensor node, E is a connecting line of a graph, the distributed switch control terminal is divided into different protection sections by the edge calculation unit according to the line topology, the distributed switch control terminal is used as a boundary, the current electric field sensor is divided into different positioning sections, and the current electric field sensor is used as a boundary;
s5, processing the short-circuit fault information and the recording waveform data to determine the direction of the short-circuit fault current;
s6, determining a positioning section according to the short-circuit fault current direction of the current electric field sensor;
s7, according to the positioning section, the short-circuit fault information and the wave recording waveform data convergence protection section, positioning the fault and determining the only protection section;
s8, comparing the distributed switch control terminal F at the boundary k And the current electric field sensor S m The short-circuit fault information is used for obtaining fault isolation data, and the distributed switch control terminal is used for isolating the protection section according to the fault isolation data.
The invention adopts an edge computing unit, switch control terminals distributed in the whole network and current electric field sensors distributed in the whole network, and the edge computing unit is provided with a short-circuit fault positioning algorithm module and a short-circuit fault isolation strategy module, so that the method is suitable for short-circuit fault positioning and short-circuit fault isolation of a novel power system under the condition of distributed energy access. The system compatibility and feasibility are provided, and the traditional distribution network construction is conveniently improved. According to the method, the current electric field sensors are adopted to form the active power distribution network short-circuit fault direction protection in a distributed mode according to the position of a circuit topological structure, and the protection is not influenced by the access of a high-permeability new energy power supply and the closed-loop operation of the power supply; the current electric field sensor has low cost and small volume, does not need to be installed in a power failure mode, and is very convenient for the reconstruction of the existing system.
In a more specific embodiment, step S1 includes:
s11, collecting three-phase current data of the distribution line in real time by using a full-network distribution switch control terminal;
and S12, collecting the three-phase current data of the distribution line and the three-phase electric field data of the distribution line in real time by using the full-network distributed current electric field sensor.
In a more specific technical solution, the step S2 includes:
s21, judging short-circuit faults by using the distributed switch control terminal and the distributed current electric field sensor according to the line current electric field data to acquire short-circuit fault information;
and S22, triggering the distributed switch control terminal to record waves according to the short-circuit fault information to obtain three-phase current and three-phase electric field waveforms, and accordingly obtaining the waveform data of the recorded waves.
In a more specific technical solution, the step S21 includes:
s211, setting a short-circuit fault current constant value I at the switch control terminal set Alarm time T of short-circuit fault set ；
S212, maximum phase current I max Greater than the short-circuit fault current constant value I set After the short-circuit fault alarm time T set After the time, it is determined that a short-circuit fault has occurred.
In a more specific embodiment, in step S3, the distribution switch control terminals distributed in the distribution line transmit the short-circuit fault information and the recording waveform data to the edge calculation unit.
When a short-circuit fault occurs, the edge computing unit collects fault information of the switch control terminal and the current electric field sensor and short-circuit fault time, and calls current and electric field waveform data of the whole network terminal at the short-circuit time. When the short-circuit current provided by the distributed power supply exceeds the overcurrent detection setting value, the short-circuit fault can still be positioned, isolated and recovered through the distributed terminal and the sensor.
In a more specific technical solution, the step S5 includes:
s51, identifying the direction of the short-circuit current according to the direction of the current electric field at the short-circuit moment by the distributed current electric field sensor;
and S52, presetting that the short-circuit current flows from the bus to the line to be short-circuited in the positive direction and flows from the line to the bus to be short-circuited in the negative direction.
In a more specific technical solution, in the step S6, the current electric field sensor is used to form a positioning area with the following logic:
Z l1 ＝(,G1)，Z l2 ＝(G1,G2)，Z l3 ＝(G2,G3)，Z l4 ＝(G3,G4,G5,G6)，Z l5 ＝(G4,)，Z l6 ＝(G5,)，Z l7 ＝(G6,G7)，Z l8 ＝(G7,G8,G9)，Z l9 ＝(G8,)，Z l10 (G9) wherein Z is l1 ...Z l10 For the positioning segments, G1, G2, G3, G4, G5, G6, G7, G8, G9 are current electric field sensors.
According to the topological structure of the power distribution network, the switch control terminal is divided into different protection sections, and the current electric field sensor is divided into different positioning sections; the switch control terminal acquires three-phase current waveforms of the distribution line in real time; the current electric field sensor collects three-phase current and three-phase electric field waveforms of the distribution line in real time. By arranging the low-cost current electric field sensor, the fault positioning section is ensured to be more dense, and the fault positioning precision is improved.
In a more specific technical solution, in step S7, a protection area is formed by using the distributed switch control terminals according to the following logic:
Z p1 ＝(,FS1),Z p2 ＝(FS1,FS2,FS3,FS4,FJ1),Z p3 ＝(FS2,LSW1),Z p4 ＝(FJ1,),Z p5 ＝(FS4,FJ2,FS5),Z p6 ＝(FJ2,),Z p7 (FS5, LSW3) wherein Z p1 ...Z p7 For the protection section, FS1 is an edge calculation unit and a switch control terminal, FS2, FS3, FS4, FS5, FJ1, and FJ2 are normal switch control terminals, and LSW1, LSW2, and LSW3 are interconnection switches.
In a more specific technical solution, the step S8 includes:
s801, determining the fault current direction according to the current electric field vector direction of the current electric field sensor;
s802, searching a section in which only short-circuit current flows in and no short-circuit current flows out in the positioning section as a short-circuit fault positioning area;
s803, judging whether the short-circuit fault positioning area is in a protection area;
s804, if yes, the current area is judged to be a short-circuit fault area, and the current protection area is a fault isolation area;
s805, if not, judging whether the distributed switch control terminal positioned on the boundary has short-circuit current;
s806, if yes, judging whether the two distributed switch control terminals positioned on the boundary have short-circuit current or not;
s807, if yes, judging whether the current vectors of the two boundary terminals are consistent;
s808, if yes, taking the switch control terminal as a boundary short-circuit fault positioning area so as to isolate the protection section;
s809, if not, taking the two boundary areas as short-circuit fault positioning areas;
and S810, if not, taking the switch control terminal as the boundary short-circuit fault positioning area so as to isolate the protection section.
In a more specific technical solution, a novel power system short-circuit fault location isolation system includes:
the electric power electric field acquisition unit is used for acquiring and acquiring real-time line current electric field data;
the wave recording unit is used for processing the real-time line current electric field data to acquire short-circuit fault information and wave recording waveform data according to the short-circuit fault information, and is connected with the electric power electric field acquisition unit;
the transmission unit is used for transmitting the short-circuit fault information and the wave recording waveform data to the edge calculation unit and is connected with the wave recording unit;
an edge calculation unit for obtaining the line topology with the following logic:
G＝(V,E)
V＝V 0 ,V 1 ,V 2 ,…V n
F＝F 0 ,F 1 ,…F p |F∈V
S＝S 0 ,S 1 ,…S q |S∈V
E＝{(V i ,V j )|V i ,V j ∈V}i,j＝0,1,…n
in the formula, a distributed switch control terminal and a current electric field sensor device form a node V of the line topology, F is a distributed switch terminal node, S is a distributed current electric field sensor node, E is a connection line of a graph, the distributed switch control terminal is divided into different protection sections by the edge calculation unit according to the line topology, the distributed switch control terminal is used as a boundary, the current electric field sensor is divided into different positioning sections, the current electric field sensor is used as a boundary, and the edge calculation unit is connected with the transmission unit;
the current direction unit is used for processing the short-circuit fault information and the recording waveform data so as to determine the current direction of the short-circuit fault, and the current direction unit is connected with the edge calculation unit;
the positioning section unit is used for determining a positioning section according to the short-circuit fault current direction of the current electric field sensor, and the positioning section unit is connected with the current direction unit;
a unique section determining unit, configured to converge a protection section according to the positioning section, the short-circuit fault information, and the recording waveform data, to position a fault and determine the unique protection section, where the unique section determining unit is connected to the positioning section unit;
a fault isolation unit for comparing the distributed switch control terminals F located at the boundary k And the current electric field sensor S m The short-circuit fault information of (2) so as to obtain fault isolation data, and the protection section is isolated by using the distributed switch control terminal according to the fault isolation data, wherein the fault isolation unit is connected with the unique section determination unit.
Compared with the prior art, the invention has the following advantages: the invention adopts an edge computing unit, switch control terminals distributed and arranged in the whole network and current electric field sensors distributed and arranged in the whole network, and the edge computing unit is deployed with a short-circuit fault positioning algorithm module and a short-circuit fault isolation strategy module, thereby being suitable for short-circuit fault positioning and short-circuit fault isolation of a novel power system under the condition of distributed energy access. The system compatibility and feasibility are provided, and the traditional distribution network construction is conveniently improved. According to the method, the current electric field sensors are adopted to form the active power distribution network short-circuit fault direction protection in a distributed mode according to the position of a circuit topological structure, and the protection is not influenced by the access of a high-permeability new energy power supply and the closed-loop operation of the power supply; the current electric field sensor has low cost and small volume, does not need to be installed in a power failure mode, and is very convenient for the reconstruction of the existing system.
When a short-circuit fault occurs, the edge computing unit collects fault information of the switch control terminal and the current electric field sensor and short-circuit fault time, and calls current and electric field waveform data of the whole network terminal at the short-circuit time. When the short-circuit current provided by the distributed power supply exceeds the over-current detection setting value, the short-circuit fault can still be positioned, isolated and recovered through the distributed terminal and the sensor.
According to the topological structure of the power distribution network, the switch control terminal is divided into different protection sections, and the current electric field sensor is divided into different positioning sections; the method comprises the steps that a switch control terminal collects three-phase current waveforms of a distribution line in real time; the current electric field sensor collects three-phase current and three-phase electric field waveforms of the distribution line in real time. By arranging the low-cost current electric field sensor, the fault positioning section is ensured to be more dense, and the fault positioning precision is improved.
In conclusion, the invention solves the technical problems of poor compatibility and low fault positioning precision in the prior art.
Drawings
FIG. 1 is a schematic diagram of a novel power system fault location and isolation system distribution;
fig. 2 is a schematic diagram of the steps of a novel power system fault location and isolation method.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The invention adopts the following technical scheme: a novel power system short-circuit fault positioning and short-circuit fault isolating system and method based on edge calculation comprises the following steps: the edge calculation unit, the switch control terminals distributed in the whole network and the current electric field sensors distributed in the whole network; the edge computing unit is provided with a short-circuit fault positioning algorithm module and a short-circuit fault isolation strategy module, the switch control terminal is divided into different protection sections according to the topological structure of the power distribution network, and the current electric field sensor is divided into different positioning sections; the method comprises the steps that a switch control terminal collects three-phase current waveforms of a distribution line in real time; the current electric field sensor acquires three-phase current and three-phase electric field waveforms of the distribution line in real time; when a short-circuit fault occurs, the edge computing unit collects fault information of the switch control terminal and the current electric field sensor and short-circuit fault time, and calls current and electric field waveform data of the whole network terminal at the short-circuit time;
as shown in fig. 2, the short-circuit fault locating method includes the following steps:
step 1: the method comprises the steps that a full-network distribution switch control terminal collects three-phase current data of a distribution line in real time; the method comprises the steps that a full-network distributed current electric field sensor collects three-phase current and three-phase electric field data of a distribution line in real time;
and 2, step: and the distributed switch control terminal and the distributed current electric field sensor judge the short-circuit fault and trigger the terminal to record the waveform data of the three-phase current and the three-phase electric field.
And step 3: the whole network terminal sends the short-circuit fault information and the wave recording waveform data to the edge computing unit;
and 4, step 4: the edge computing unit divides the switch control terminal into different protection sections Z according to the circuit topology p Dividing the current electric field sensor into different positioning sections Z by taking the switch control terminal as a boundary l A current electric field sensor is used as a boundary;
and 5: the current electric field sensor determines the fault current direction through short-circuit fault information and the vector direction of the current and electric field of the recording waveform;
step 6: determining a positioning section Z according to the direction of the short-circuit fault current of the current electric field sensor li ；
And 7: according to the location zone Z li And carrying out protection zone convergence by short-circuit fault information and short-circuit fault waveform, and determining a unique protection zone Z pi Completing the positioning of the fault and the determination of the protection section;
further, in step 2: switch control terminal sets short-circuit fault current constant value I set Alarm time T of short-circuit fault set (ii) a When the maximum phase current I max Is greater than I set Meridian T set After time, the short-circuit fault is judged, and the three-phase current waveform is recorded by the terminal. Current electric field sensor set short-circuit current sudden change constant value Ibrk set (ii) a When the current mutation constant value exceeds Ibrk set And if the line is in power failure, judging that the line is in short circuit fault, and recording the waveform of the three-phase current electric field by the terminal.
Further, in step 4: using graph G to represent the line topology, then
G＝(V,E) (1)
V＝V 0 ,V 1 ,V 2 ,…V n (2)
F＝F 0 ,F 1 ,…F p |F∈V (3)
S＝S 0 ,S 1 ,…S q |S∈V (4)
E＝{(V i ,V j )|V i ,V j ∈V}i,j＝0,1,…n (5)
In the formula: the distributed switch terminals and the current electric field sensor devices form a node V of the graph; f is a distributed switch terminal node, and S is a distributed current electric field sensor node; e is the connecting line of the figure.
Protective zone Z p Is a closed section formed by a switch control terminal node F; location zone Z l Is a closed section formed by the current electric field sensor node S.
Further, in step 6: location zone Z li Only short-circuit fault current flows in, and the section without short-circuit fault outflow is a fault section;
further, in step 7: location zone Z li Whether or not it includes a switch control terminal F k ：
Presence of F k ∈Z li Find switch control terminal F k Corresponding current electric field sensor S m Executing step 8;
location zone Z li The switch control terminal is not included in the protection system, the positioning section is a fault positioning section, the protection section including the positioning section is a fault protection section, and step 9 is executed;
and 8: comparative boundary switch control terminal F k And a current electric field sensor S m Short-circuit fault information:
F k and S m All have no short-circuit fault information, then use F k Substitution of S m As Z li Locating a segment boundary;
F k and S m All have only one short-circuit fault information, then Z li Segment is (F) k ,S m )；
F k And S m All have short-circuit fault information, compare F k And S m Waveform current angle:
F k and S m If the short-circuit current has the same waveform angle, F is used k Substitution of S m As Z li Locating a segment boundary;
F k and S m If the short-circuit current waveform angles are not consistent, then Z li Segment is (F) k ,S m )；
Repeating the step 7;
and step 9: finishing protection zone Z by distributed switch control terminal pi And carrying out fault isolation.
Compared with the existing active power distribution network fault location, the novel power system fault location and isolation method provided by the invention has the following advantages:
the compatibility is good, the feasibility is high, and the traditional distribution network construction is conveniently reconstructed. The method adopts the current electric field sensor to form the short-circuit fault direction protection of the active power distribution network, and is not influenced by the access of a high-permeability new energy power supply and the closed loop operation of the power supply; the current electric field sensor has low cost and small volume, does not need to be installed in a power failure mode, and is very convenient for the reconstruction of the existing system.
The positioning precision is high. By arranging the low-cost current electric field sensor, a fault positioning section is ensured to be more dense, and the positioning precision is high.
Example 2
CB1 is a line outlet recloser as shown in FIG. 1, FS1 is an edge calculation unit and a switch control terminal; FS2, FS3, FS4, FS5, FJ1, FJ2 are normal switch control terminals; g1, G2, G3, G4, G5, G6, G7, G8 and G9 are current electric field sensors; LSW1, LSW2 and LSW3 are interconnection switches; DG is a Distributed energy source (Distributed Generation) and all end devices need to communicate with FS 1.
The switch control terminal forms a protection zone Z p1 ＝(,FS1),Z p2 ＝(FS1,FS2,FS3,FS4,FJ1),Z p3 ＝(FS2,LSW1),Z p4 ＝(FJ1,),Z p5 ＝(FS4,FJ2,FS5),Z p6 ＝(FJ2,),Z p7 ＝(FS5,LSW3)
The current electric field sensor forms a positioning area Z l1 ＝(,G1)，Z l2 ＝(G1,G2)，Z l3 ＝(G2,G3)，Z l4 ＝(G3,G4,G5,G6)，Z l5 ＝(G4,)，Z l6 ＝(G5,)，Z l7 ＝(G6,G7)，Z l8 ＝(G7,G8,G9)，Z l9 ＝(G8,)，Z l10 ＝(G9,)
Switch control terminal sets short-circuit fault current constant value I set Alarm time T of short-circuit fault set (ii) a When the maximum phase current I max Is greater than I set Meridian T set After time, the short-circuit fault is judged, and the three-phase current waveform is recorded by the terminal.
Current electric field sensor short-circuit fault sudden-change current threshold Ibrk set Under normal conditions Ibrk set Set at 150A, when the short-circuit fault of the line causes tripping, the current electric field sensor detects that the current mutation exceeds Ibrk set And if the line is in power failure, the short-circuit fault is judged, and the three-phase current and the three-phase electric field waveform are recorded at the terminal.
When a short-circuit fault occurs, the edge calculation unit collects all terminal short-circuit fault data and short-circuit waveform data at the time of the short-circuit fault.
The current electric field sensor identifies the direction of the short-circuit current according to the direction of the current electric field at the short-circuit moment, and specifies that the short-circuit current flows from the bus to the line to be short-circuited in a positive direction and flows from the line to the bus to be short-circuited in a negative direction.
Statistical localization zone short circuit Z li The positive short circuit number n, n is the area of 1, which is the fault area, and all fault currents flow into the area; n is>The area of 1 is a non-failure area, and a failure current flows in and a failure current flows out.
Convergence of the positioning area is performed, and the switch control terminal (switch control terminal device for checking the positioning area) included in the positioning area is searched
If there is a switch control terminal FS i Then, the current and voltage sensor G of the positioning area singly connected with the switch control terminal is searched j If FS i And G j If there is no short-circuit fault signal, FS is used i Substitution of G j As the boundary of the positioning area; if FS i And G j If there is a short-circuit fault signal, the location area converges to Z l ＝(FS i ,G j ) (ii) a If FS i And G j If there is a short-circuit fault signal, judging the direction of the short-circuit current vector, if FS i And G j If the current directions are the same, FS is used i Substitution of G j As a boundary of the positioning area, if FS i And G j If the current directions are not the same, the positioning region converges to Z l ＝(FS i ,G j )。
Repeating the convergence step until the positioning area is contained in a protection area, and determining the positioning area and the protection area as final positioning areas and final protection areas.
And fault isolation is carried out on the fault area through the switch control terminal.
In summary, the invention is composed of an edge computing unit, switch control terminals distributed in the whole network, and current electric field sensors distributed in the whole network, and the edge computing unit is provided with a short-circuit fault positioning algorithm module and a short-circuit fault isolation strategy module, and is suitable for short-circuit fault positioning and short-circuit fault isolation of a new power system under the distributed energy access condition. The system compatibility and feasibility are provided, and the traditional distribution network construction is conveniently improved. According to the method, the current electric field sensors are adopted to form the active power distribution network short-circuit fault direction protection in a distributed mode according to the position of a circuit topological structure, and the protection is not influenced by the access of a high-permeability new energy power supply and the closed-loop operation of the power supply; the current electric field sensor has low cost and small volume, does not need to be installed in a power failure mode, and is very convenient for the reconstruction of the existing system.
When a short-circuit fault occurs, the edge computing unit collects fault information of the switch control terminal and the current electric field sensor and short-circuit fault time, and calls current and electric field waveform data of the whole network terminal at the short-circuit time. When the short-circuit current provided by the distributed power supply exceeds the overcurrent detection setting value, the short-circuit fault can still be positioned, isolated and recovered through the distributed terminal and the sensor.
According to the topological structure of the power distribution network, the switch control terminal is divided into different protection sections, and the current electric field sensor is divided into different positioning sections; the switch control terminal acquires three-phase current waveforms of the distribution line in real time; the current electric field sensor collects three-phase current and three-phase electric field waveforms of the distribution line in real time. By arranging the low-cost current electric field sensor, the fault positioning section is ensured to be more dense, and the fault positioning precision is improved.
In conclusion, the invention solves the technical problems of poor compatibility and low fault positioning precision in the prior art.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A novel power system short-circuit fault positioning and isolating method is characterized by comprising the following steps:
s1, acquiring real-time line current electric field data;
s2, processing the real-time line current electric field data to obtain short-circuit fault information, and obtaining wave recording waveform data according to the short-circuit fault information;
s3, transmitting the short-circuit fault information and the wave recording waveform data to an edge calculation unit;
s4, obtaining the line topology with the following logic:
G＝(V,E)
V＝V 0 ,V 1 ,V 2 ,…V n
F＝F 0 ,F 1 ,…F p |F∈V
S＝S 0 ,S 1 ,…S q |S∈V
E＝{(V i ,V j )|V i ,V j ∈V}i,j＝0,1,…n
in the formula, the distributed switch control terminal and the current electric field sensor device form a node V of the line topology; f is a distributed switch terminal node, S is a distributed current electric field sensor node, E is a connecting line of a graph, the edge calculation unit divides the distributed switch control terminal into different protection sections according to the circuit topology, the distributed switch control terminal is used as a boundary, the current electric field sensor is divided into different positioning sections, and the current electric field sensor is used as a boundary;
s5, processing the short-circuit fault information and the recording waveform data to determine the direction of the short-circuit fault current;
s6, determining a positioning section according to the short-circuit fault current direction of the current electric field sensor;
s7, according to the positioning section, the short-circuit fault information and the wave recording waveform data convergence protection section, positioning the fault and determining the only protection section;
s8, comparing the distributed switch control terminal F at the boundary k And the current electric field sensor S m The short-circuit fault information is used for obtaining fault isolation data, and the distributed switch control terminal is used for isolating the protection section according to the fault isolation data.
2. The novel power system short-circuit fault location and isolation method according to claim 1, wherein the step S1 includes:
s11, collecting three-phase current data of the distribution line in real time by using a full-network distribution switch control terminal;
and S12, collecting the three-phase current data of the distribution line and the three-phase electric field data of the distribution line in real time by using the full-network distributed current electric field sensor.
3. The novel power system short-circuit fault location and isolation method according to claim 1, wherein the step S2 includes:
s21, judging short-circuit faults by using the distributed switch control terminal and the distributed current electric field sensor according to the line current electric field data to acquire short-circuit fault information;
and S22, triggering the distributed switch control terminal to record waves according to the short-circuit fault information to obtain three-phase current and three-phase electric field waveforms, and accordingly obtaining the waveform data of the recorded waves.
4. The novel power system short-circuit fault location and isolation method according to claim 3, wherein the step S21 includes:
s211, setting a short-circuit fault current constant value I at the switch control terminal set Alarm time T of short-circuit fault set ；
S212, maximum phase current I max Greater than the short-circuit fault current constant value I set Alarm time T of said short-circuit fault set After the time, it is determined that a short-circuit fault has occurred.
5. The method as claimed in claim 1, wherein in step S3, the distribution switch control terminals distributed in the distribution line transmit the short-circuit fault information and the recording waveform data to the edge computing unit.
6. The novel power system short-circuit fault location and isolation method according to claim 1, wherein the step S5 includes:
s51, identifying the direction of the short-circuit current according to the direction of the current electric field at the short-circuit moment by the distributed current electric field sensor;
and S52, presetting that the short-circuit current flows from the bus to the line to be short-circuited in the positive direction and flows from the line to the bus to be short-circuited in the negative direction.
7. The method as claimed in claim 1, wherein in step S6, the current electric field sensor is used to form a location area with the following logic:
Z l1 ＝(,G1)，Z l2 ＝(G1,G2)，Z l3 ＝(G2,G3)，Z l4 ＝(G3,G4,G5,G6)，Z l5 ＝(G4,)，Z l6 ＝(G5,)，Z l7 ＝(G6,G7)，Z l8 ＝(G7,G8,G9)，Z l9 ＝(G8,)，Z l10 ＝(G9,)
in the formula, Z l1 ...Z l10 For the positioning segments, G1, G2, G3, G4, G5, G6, G7, G8, G9 are current electric field sensors.
8. The method according to claim 1, wherein in step S7, the distributed switch control terminals are used to form a protection area with the following logic:
Z p1 ＝(,FS1),Z p2 ＝(FS1,FS2,FS3,FS4,FJ1),Z p3 ＝(FS2,LSW1),Z p4 ＝(FJ1,),Z p5 ＝(FS4,FJ2,FS5),Z p6 ＝(FJ2,),Z p7 ＝(FS5,LSW3)
in the formula, Z p1 ...Z p7 For the protection section, FS1 is an edge calculation unit and a switch control terminal, FS2, FS3, FS4, FS5, FJ1, and FJ2 are normal switch control terminals, and LSW1, LSW2, and LSW3 are interconnection switches.
9. The novel power system short-circuit fault location and isolation method according to claim 1, wherein the step S8 includes:
s801, determining the fault current direction according to the current electric field vector direction of the current electric field sensor;
s802, searching a section in which only short-circuit current flows in and no short-circuit current flows out in the positioning section as a short-circuit fault positioning area;
s803, judging whether the short-circuit fault positioning area is in a protection area;
s804, if yes, the current area is judged to be a short-circuit fault area, and the current protection area is a fault isolation area;
s805, if not, judging whether the distributed switch control terminal positioned on the boundary has short-circuit current;
s806, if yes, judging whether the two distributed switch control terminals located on the boundary have short-circuit current or not;
s807, if yes, judging whether the current vectors of the two boundary terminals are consistent;
s808, if yes, taking the switch control terminal as a boundary short-circuit fault positioning area so as to isolate the protection section;
s809, if not, using the two boundary areas as short-circuit fault positioning areas;
and S810, if not, taking the switch control terminal as the boundary short-circuit fault positioning area so as to isolate the protection section.
10. A novel power system short circuit fault location isolation system, the system comprising:
the electric power electric field acquisition unit is used for acquiring and acquiring real-time line current electric field data;
the wave recording unit is used for processing the real-time line current electric field data to acquire short-circuit fault information and wave recording waveform data according to the short-circuit fault information, and is connected with the electric power electric field acquisition unit;
the transmission unit is used for transmitting the short-circuit fault information and the wave recording waveform data to the edge calculation unit and is connected with the wave recording unit;
an edge calculation unit for obtaining the line topology with the following logic:
G＝(V,E)
V＝V 0 ,V 1 ,V 2 ,…V n
F＝F 0 ,F 1 ,…F p |F∈V
S＝S 0 ,S 1 ,…S q |S∈V
E＝{(V i ,V j )|V i ,V j ∈V}i,j＝0,1,…n
in the formula, the distributed switch control terminal and the current electric field sensor device form a node V of the line topology; f is a distributed switch terminal node, S is a distributed current electric field sensor node, E is a connecting line of a graph, an edge calculation unit divides the distributed switch control terminal into different protection sections according to the circuit topology, the distributed switch control terminal is used as a boundary, the current electric field sensor is divided into different positioning sections, the current electric field sensor is used as a boundary, and the edge calculation unit is connected with the transmission unit;
the current direction unit is used for processing the short-circuit fault information and the recording waveform data so as to determine the short-circuit fault current direction, and the current direction unit is connected with the edge calculation unit;
the positioning section unit is used for determining a positioning section according to the short-circuit fault current direction of the current electric field sensor, and the positioning section unit is connected with the current direction unit;
a unique section determining unit, configured to converge a protection section according to the positioning section, the short-circuit fault information, and the recording waveform data, to position a fault and determine the unique protection section, where the unique section determining unit is connected to the positioning section unit;
a fault isolation unit for comparing the distributed switch control terminals F located at the boundary k And the current electric field sensor S m The short-circuit fault information of (2) so as to obtain fault isolation data, and the protection section is isolated by using the distributed switch control terminal according to the fault isolation data, wherein the fault isolation unit is connected with the unique section determination unit.
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| CN115579851A (en) * | 2022-11-21 | 2023-01-06 | 南京国电南自电网自动化有限公司 | Active detection type power distribution network fault isolation and self-healing method and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115579851A (en) * | 2022-11-21 | 2023-01-06 | 南京国电南自电网自动化有限公司 | Active detection type power distribution network fault isolation and self-healing method and system |
| CN115579851B (en) * | 2022-11-21 | 2023-03-24 | 南京国电南自电网自动化有限公司 | Active detection type power distribution network fault isolation and self-healing method and system |
| WO2024108769A1 (en) * | 2022-11-21 | 2024-05-30 | 南京国电南自电网自动化有限公司 | Active-detection-type power distribution network fault isolation and self-healing method and system |
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