CN114814450A - Power distribution network disconnection fault positioning method and system - Google Patents
Power distribution network disconnection fault positioning method and system Download PDFInfo
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- CN114814450A CN114814450A CN202210295420.1A CN202210295420A CN114814450A CN 114814450 A CN114814450 A CN 114814450A CN 202210295420 A CN202210295420 A CN 202210295420A CN 114814450 A CN114814450 A CN 114814450A
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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
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00004—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the power network being locally controlled
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
- H02J13/00022—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using wireless data transmission
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- Remote Monitoring And Control Of Power-Distribution Networks (AREA)
Abstract
The invention belongs to the technical field of disconnection fault diagnosis, and particularly relates to a method and a system for positioning a disconnection fault of a power distribution network. For a certain section of line, if the phenomenon that a certain phase current of the line drops to zero is found, other phase changes are small, the line with the upper node of the section of line as the lower node has a descending trend, other line changes with the upper node of the section of line as the lower node are small, and the line-breaking phase current of the line with the lower node of the line as the upper node drops to zero, the line-breaking phase of the line is judged to have a line-breaking fault at the current moment. The whole method does not need complex parameter calculation, the required characteristic quantity is less, the principle algorithm is simple, the calculation is faster, and the real-time performance of the disconnection fault judgment is higher. Meanwhile, the power distribution network disconnection fault system which is simple in structure and can be implemented is provided, and hardware support is provided for realizing the method.
Description
Technical Field
The invention belongs to the technical field of disconnection fault diagnosis, and particularly relates to a method and a system for positioning a disconnection fault of a power distribution network.
Background
In an electric power system, a distribution line is a key component of electric power transmission, and the power supply reliability and the power supply quality of the distribution line directly influence industrial production and social and economic development; the scale of the distribution network is increasingly large and complex along with the development of cities, the number of lines in the network is large, the number of equipment is large, the level of equipment is different, and the probability of line breakage in overhead lines of the distribution network is also increased continuously, so that line breakage faults become an important fault type of the distribution network.
The power distribution network overhead line disconnection fault is mainly caused by the following reasons: (1) electrical reasons, such as the damaged part of the electrical service life line generates heat to blow the wire due to short circuit or overload, or the wire is broken due to uneven electric field distribution; (2) external force reasons, such as the tree being blown down by wind to break the line, or the object falling down to break the line; (3) natural disaster causes such as lightning strike arc, freezing rain and icing cause disconnection; (4) the line is broken due to artificial reasons, such as poor construction quality, disorderly circuit pulling, hardware theft and the like. After a power distribution network line is broken, obvious three-phase voltage and current unbalance phenomena occur on a power supply side and a load side, so that the rotating speed of a motor is sharply reduced or even burnt due to phase-lacking operation, and serious electrical equipment damage and large economic loss are caused; meanwhile, the disconnection fault can also cause safety accidents such as electric shock of people and livestock, fire in mountain forests and the like, so that the timely identification and elimination of the disconnection fault are important responsibilities for safe operation of the power distribution network line.
The operation condition of the power distribution network is complex, and the line breaking faults comprise 3 types of line breaking ungrounded faults, line breaking power supply side ground faults and line breaking load side ground faults according to the actual line breaking condition. At present, the power distribution network is relatively mature in processing short circuit and power supply grounding faults, but monitoring and identification of other two types of disconnection faults are still deficient, and the disconnection faults are mainly processed by manual line patrol, so that the fault confirmation and processing cost is long. With the increase of attention and attention to the disconnection fault, some methods for detecting the disconnection fault are proposed by scholars, but most methods rely on complex phase, zero sequence and negative sequence component calculation, the algorithm is complex, more electrical characteristic quantities are needed, and the method has certain limitation.
In summary, the disconnection fault of the power distribution network is complex, the fault characteristics of the power distribution network are not obvious, and based on the existing relay protection and short circuit grounding fault positioning methods, a complex calculation mode is mostly adopted, the method comprises a disconnection fault judgment method based on voltage and current phasor relation or sequence component characteristic relation, the method is not suitable for the identification and positioning of the disconnection fault, and a simple, practical, economic and reliable disconnection fault identification and protection method is lacked. Therefore, how to realize the rapid detection and positioning of the disconnection fault of the power distribution network and improve the practicability, economy and reliability of the detection method is a problem which needs to be solved urgently by technical personnel in the field.
Disclosure of Invention
The invention aims to provide a method and a system for positioning a disconnection fault of a power distribution network, which are used for solving the problem that the disconnection fault positioning method in the prior art is complex.
In order to solve the technical problems, the technical scheme provided by the invention and the corresponding beneficial effects of the technical scheme are as follows:
the invention discloses a method for positioning a disconnection fault of a power distribution network, which comprises the following steps of:
1) acquiring three-phase current of each section of line on the power distribution network line; the distribution network line is provided with a plurality of nodes, all the nodes divide the distribution network line into a plurality of sections of lines, for one section of line, the node is called as an upper node of the section of line under the condition that the upstream of the section of line is connected with the node, and the node is called as a lower node of the section of line under the condition that the downstream of the section of line is connected with the node;
2) for a certain section of line, judging whether a certain or a plurality of phase currents of the certain section of line are smaller than a set zero-dropping threshold value at the current moment, if so, defining the phase smaller than the set zero-dropping threshold value as a line-breaking phase, judging whether the difference between the current-moment non-line-breaking phase current and the last-moment non-line-breaking phase current of the certain section of line is within a set difference range, if so, defining the certain section of line as the line to be diagnosed, and executing the step 3) to further judge;
3) judging whether the following judgment conditions are met, if so, judging that the line breaking fault of the line to be diagnosed occurs at the current moment; the judgment condition includes:
the method comprises the following steps that 1, the current of the line breaking phase current of a line with an upper node of the line to be diagnosed as a lower node at the current moment is smaller than the current of the line breaking phase current at the last moment;
and 3, in the case of a line with the lower node of the line to be diagnosed as the upper node, the line-breaking phase current of the line with the lower node of the line to be diagnosed as the upper node is smaller than the set zero-dropping threshold value.
The beneficial effects of the above technical scheme are: the method is designed by utilizing the characteristics that when the power distribution network line has an open circuit fault, the influence on the power distribution network line at the downstream of the fault point is large, and the influence on the power distribution network line at the upstream of the fault point is small.
Further, in order to accurately locate the fault position, after it is determined that the line to be diagnosed has the disconnection fault at the current moment, the line to be diagnosed is further photographed to determine the specific geographical position of the disconnection fault in the line to be diagnosed.
Further, in step 2), the difference between the current-time non-line-break phase current and the previous-time non-line-break phase current of the certain section of line is calculated by the following method: and calculating the ratio of the difference value of the current-time non-broken-line phase current and the last-time non-broken-line phase current of the certain section of line to the current-time non-broken-line phase current.
Further, in step 3), the difference between the current of the other line at the current moment and the current of the other line at the previous moment is calculated by the following method: and calculating the ratio of the difference value of the current time current of other lines and the current time current of the previous line to the current time current of other lines.
Further, the set difference range is less than 10%.
The invention discloses a power distribution network disconnection fault positioning system which comprises a remote positioning module and branch control modules corresponding to nodes on a power distribution network line, wherein each branch control module is in communication connection with the remote positioning module;
each branch control module comprises a core control unit, a line acquisition unit and a power supply unit; the power supply unit is in power supply connection with the core control unit;
the core control unit samples a connection circuit acquisition unit; if the node is a first node, the upstream of the line with the first node as a lower node is a node on the power supply side, the line acquisition unit corresponding to the node comprises a current sensor which is arranged on the line with the first node as an upper node and is used for acquiring three-phase current on the line, and a current sensor which is arranged on the line with the first node as a lower node and is used for acquiring three-phase current on the line; if the node is not the first node, the line acquisition unit corresponding to the node comprises a current sensor which is arranged on the line with the corresponding node as the upper node and is used for acquiring three-phase current on the line;
the remote positioning module comprises an industrial server and is used for realizing the introduced power distribution network disconnection fault positioning method according to the acquired data.
The beneficial effects of the above technical scheme are: the system is designed for matching with the method for positioning the disconnection fault of the power distribution network, a plurality of branch control modules are designed in the system, each branch control module is responsible for collecting the change condition of partial line current, the division of labor is clear, hardware support is provided for the method for positioning the disconnection fault of the power distribution network, and the reliable operation of the whole system is ensured.
Furthermore, in order to accurately position the fault position, each branch control module further comprises an image acquisition unit corresponding to a node on the power distribution network line, and the image acquisition unit is used for shooting the line to be diagnosed.
Further, in order to ensure the reliable operation of the system and save energy, the power supply unit comprises a solar main power supply and a backup battery, and the solar main power supply is connected with the backup battery in a power supply mode.
Furthermore, in order to realize reliable communication between the branch control modules and the remote positioning module, each branch control module and the remote positioning module adopt a narrow-band Internet of things communication mode.
Furthermore, in order to facilitate the staff to check the fault position, the remote positioning module further comprises a human-computer interaction unit and a graphic display unit which are connected with the industrial server.
Drawings
FIG. 1 is a schematic diagram of a power distribution network outage fault location system of the present invention;
FIG. 2 is an electrical schematic of the power distribution network outage fault location system of the present invention;
FIG. 3 is a schematic diagram of a communication network of the power distribution network outage fault location system of the present invention;
FIG. 4 is a schematic diagram of a branch control module of the present invention;
fig. 5 is a schematic diagram of another power distribution network outage fault location system of the present invention.
The system comprises a 1-remote positioning module, 2-n branch control modules, 10-an industrial server, 11-a graphic display unit, 12-a man-machine interaction unit, 20-a core control unit, 21-a line acquisition unit, 22-an image acquisition unit, 23-a power supply unit, 210-218-acquisition assemblies, 220-a high-definition camera shooting assembly, 221-a tripod head control assembly, 230-a power supply management assembly, 231-a standby power supply and 232-a solar main power supply.
Detailed Description
The invention designs a power distribution network disconnection fault positioning method by utilizing the characteristics that when a power distribution network line has a disconnection fault, the power distribution network line at the downstream of a fault point is greatly influenced and the power distribution network line at the upstream of the fault point is slightly influenced, and simultaneously provides a power distribution network disconnection fault positioning system for realizing the method. The power distribution network disconnection fault positioning system and the power distribution network disconnection fault positioning method of the invention are further described in detail with reference to the accompanying drawings and the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.
The embodiment of the system is as follows:
the embodiment of the power distribution network disconnection fault positioning system aims at the power distribution network system in figure 1, n-1 nodes are arranged on a main line of the power distribution network, the n-1 nodes are called as a node 1, a node 2, … … and a node n-1 according to the sequence from left to right in figure 1, and the n-1 nodes are respectively connected with a branch line. The n-1 nodes divide the whole power distribution network line into a plurality of sections of lines, and for a certain section of line, the node is called as an upper node of the section of line when the node is connected to the upstream of the section of line, and the node is called as a lower node of the section of line when the node is connected to the downstream of the section of line. For example, for a line between node 1 and node 2, node 1 is its upper node and node 2 is its lower node; for a branch leg to which node 1 is connected, only the upper node (i.e., node 1) has no lower node.
The fault positioning system comprises a remote positioning module 1 and n-1 branch control modules which are respectively called as a branch control module 2, a second branch control module 3, … … and an n-1 branch control module n, wherein all the branch control modules are connected with the remote positioning module 1, the connection mode between the branch control module 2 and the remote positioning module 1 is shown in fig. 2, the direction of a single arrow is used for indicating the signal transmission direction of a connecting cable, and a double arrow is used for indicating the signal transmission direction of a wireless network.
The 1 branch control module corresponds to 1 node, the branch control module 2 includes a line acquisition unit 21, an image acquisition unit 22, a core control unit 20 and a power supply unit 23, and the branch control module 2 corresponds to the node 1 (the upstream of the line with the node 1 as the lower node is the power supply side, so the node 1 is the first node). The core control unit 20, the image acquisition unit 22 and the power supply unit 23 are arranged on a tower at a branch of a line as an integral structure; the line acquisition unit 21 comprises 9 acquisition communication components, the 9 acquisition communication components are respectively arranged on a main line at the upstream of the node, a main line between the node and a node at the downstream of the node and a branch line connected with the node, and are used for respectively acquiring the current at the main lines a3, b3 and c3, the main lines a1, b1 and c1 and the branch lines a2, b2 and c2, and the image acquisition unit 21 is communicated with the core control unit 20 through 433M wireless frequency; the core control unit 20 controls the image acquisition unit 22 through a power supply and a communication cable, and confirms whether to start an image acquisition action according to an instruction sent by the remote positioning module 1; the power supply unit 23 is connected with the core control unit 20 through a power cable to supply power to the branch control module 2; the branch control module 2 performs data communication with the industrial server 10 of the remote location module 1 through an NBIoT (narrowband internet of things) communication module embedded in the core control unit 20. The other branch control modules have similar structures to the branch control module 2, but because the nodes corresponding to the other branch control modules are no longer the first nodes, the number of the acquisition communication components included in the other branch control modules is 6, and the acquisition communication components included in the main line between the nodes and the nodes located downstream of the nodes and the branch line connected to the nodes are only included, and the acquisition communication components included in the main line upstream of the nodes are no longer included, and the rest contents are consistent, which is not described herein again.
As shown in fig. 3, the line acquisition unit 21 is composed of 9 acquisition communication components 210 to 218, each acquisition communication component is composed of an acquisition component and a wireless component, the hardware of the acquisition component parts of the 9 acquisition communication components are completely consistent, the consistency of acquisition precision is ensured, and the 9 acquisition communication components can be current sensors adopting a wireless communication mode. The wireless components in the 9 acquisition communication components and the wireless components in the core control unit 20 need to be designed in a matched manner, hardware delay and clock synchronization between the line acquisition unit and the core control module are guaranteed, and the line acquisition unit 21 and the wireless communication part of the core control unit 20 form a short-distance wireless network, so that wireless communication and information interaction inside the branch control module 2 are realized.
The power supply unit 23 in the branch control module 2 is composed of a standby battery 231, a solar main power supply 232 and a power supply management assembly, the power supply management assembly is responsible for charging and discharging control of the standby battery and power supply management of the core control unit 20, when the energy of the solar main power supply 232 is sufficient, the power supply of the core control unit 20 is provided by the solar main power supply 232, meanwhile, redundant energy is distributed to the standby battery for charging, and when the solar main power supply 232 enters the night or the energy of the solar main power supply 232 is insufficient, the power supply of the core control unit 20 is dynamically managed and controlled by the standby battery 231 and the solar main power supply 232 through the power supply management assembly to supply power; the power management component simultaneously carries out protection management on overcharge and overdischarge of the standby battery.
As shown in fig. 4, the image capturing unit 22 is composed of a high definition camera module 220 and a pan/tilt control module 221, and is connected to the core control unit 20 through a cable, and the core control unit adjusts the angle of the pan/tilt control module 221 and the focal length of the high definition camera module 220 according to the control command of the remote positioning module 1.
The remote positioning module 1 comprises an industrial server 10, a graphic display unit 11 and a human-computer interaction unit 12. The industrial server 10 is suitable for industrial application and network environment thereof, and has higher processing capacity, transmission speed, function expansion capacity, safety, reliability and manageability than the traditional industrial personal computer; the industrial server 10 communicates with the graphic display unit 11 through a video cable; the graphic display unit 011 realizes graphic display of a line and a branch control module device installed on site, and geographical coordinates of the installation position of the branch control module are displayed on a graphic. The man-machine interaction unit 12 is connected with the industrial server 10 through an IO cable, and functions of various instruction operation control, device operation parameter setting, graphical interface operation and input and the like of the device are achieved.
The industrial server 10 in the remote positioning module 1 is composed of an NB-IoT communication component and an industrial server core component, the industrial server core component is responsible for data management of n-1 managed line branch modules, disconnection software logic control and graphic data editing control, the NB-IoT communication component and the NB-IoT communication component inside the branch control module are completely consistent in hardware design and form an efficient Internet of things communication network, and real-time communication data interaction of the remote positioning module and the branch control module is achieved.
Based on the power distribution network disconnection fault positioning system, the power distribution network disconnection fault positioning method can be realized, and the method is described in detail below.
Step one, collecting current data of field operation through a collecting communication assembly in each branch control module, analyzing and processing to determine a broken line phase and a line to be diagnosed, and uploading the analysis and processing result to a remote positioning module 1.
For example, for the branch control module 3, 6 acquisition communication components in the branch control module acquire the main line current and the branch line circuit corresponding to the node in real time, and the 6 acquisition communication modules send acquired current data to the core control unit; after correcting wireless network transmission delay errors through software, the core control unit records relevant current amplitude and time scales, judges the current of each acquisition communication component at the current moment, judges whether a certain phase or a plurality of phases of current of each line are smaller than a set zero-dropping threshold (the zero-dropping threshold is set to be smaller and approximately equal to zero) or not, if a certain phase has the zero-dropping phenomenon (for example, a sensor at the position of a phase a1 detects that the zero-dropping phenomenon occurs in a phase A main line between a node 2 and a node 3), defines the phase as a broken line phase, calls the non-broken line phase current of the line at the moment, judges whether the difference between the non-broken line phase current at the current moment and the non-broken line phase current at the last moment is within a set difference range (for example, the sensor at the position of B phase B1 at the current moment detects that the phase of the phase B circuit current changes by no more than 10% than the last moment), and the sensor at the position of C phase C1 at the current moment detects that the change of the C phase circuit current phase is not more than 10% compared with the last moment, if the change is satisfied, the first disconnection judgment condition is judged to be satisfied; and then, defining the main line between the node 2 and the node 3 as the line to be diagnosed. Thereafter, the core control unit sends the analysis results including the phase of the disconnection, the line to be diagnosed, and the time stamp (here, the current time) to the industrial server in the remote location module 1 through the NB-IoT communication component.
And step two, after receiving the analysis result sent by the branch control module 3, the remote positioning module 1 acquires the data acquired by the acquisition communication modules in the branch control module 2 and the branch control module 4, and further analyzes and processes the data.
The industrial server generates a logic diagram according to the installation information of the branch control module 3 to confirm the addresses of other branch control modules installed in front of and behind the branch control module 3; and according to the related address calling criterion, the related current amplitude information of other branch control modules arranged in front of and behind the branch control module 3 under the same time scale is tested. And the remote positioning module starts a second-stage judgment according to the called line installation module data, and logically analyzes the current information of the branch control modules arranged before and after the branch control module according to the criterion 1 to obtain the current change trend. Specifically, the method comprises the following steps:
in the step one, the broken line phase is phase a, and the line between the node 2 and the node 3 is a line to be diagnosed, then the line with the upper node (node 2) of the line to be diagnosed as the lower node is a main line between the node 1 and the node 2, the other line with the upper node (node 2) of the line to be diagnosed as the upper node is a branch line connected at the node 2, and the line with the lower node (node 3) of the line to be diagnosed as the upper node includes the main line between the node 3 and a node 4 (not shown in the figure) and the branch line connected at the node 3, which are arranged after the node 3. At this time, it is necessary to obtain current information from the branch control module 2 and the branch control module 4 (not shown in the figure), and determine whether the current-time phase a current on the main line between the node 1 and the node 2 is smaller than the current of the broken line at the previous time (i.e. has a downward trend), and whether the difference between the current-time current and the current of the branch line connected at the node 2 at the previous time is within a set difference range (for example, the ratio between the current-time current difference and the current at the previous time is within a range of 10%), if both are satisfied, it is defined that the second broken line determination condition is satisfied. And then, whether the A-phase current of the main line between the node 3 and the node 4 and the branch line connected with the node 3 is smaller than a set zero-drop threshold value or not is judged, and if yes, a third disconnection judgment condition is met. At this time, it can be determined that the main line between the node 2 and the node 3 has a disconnection fault at the present time.
And step three, after the broken line is determined, starting closed-loop image verification work, starting a camera arranged at the branch control module 3 by the remote positioning module 1, acquiring field images with different directions and focal lengths on the line, sending the field images to a graphic display unit in the remote positioning module through an NBIoT (narrow-band Internet of things) communication module, confirming the acquired broken line images by the remote positioning module, confirming the specific position of broken line, and completing the closed-loop verification logic of the broken line fault.
It should be noted that, in the second step, if there is no other line except the line to be diagnosed, which uses the upper node of the line to be diagnosed as the upper node, it is not necessary to determine the difference between the current of the other line at the current moment and the current at the previous moment; if the line with the lower node of the line to be diagnosed as the upper node does not exist, whether the line breaking phase current of the line with the lower node of the line to be diagnosed as the upper node is smaller than the set zero-dropping threshold value does not need to be calculated.
In the second step, the difference between the two currents is determined according to percentage. As another embodiment, the difference between the two currents may be directly calculated, a difference threshold is correspondingly set, and the difference between the two currents is determined by using the relationship between the actual difference and the difference threshold.
In addition, the invention is further described in connection with a complex distribution network. The distribution network line shown in fig. 5 represents an actual three-phase line by one line, 5 nodes k 1-k 5 are arranged on the whole line, nodes k 1-k 3 are arranged on a main line, nodes k 4-k 5 are arranged on a branch line, and the 5 nodes divide the whole distribution network line into 12 lines l 1-l 12. For a line, the node connected upstream is referred to as the upper node of the line segment, and the node connected downstream is the lower node of the line segment. For example, for line l1, its upper node is node k1, and its lower node is node k 2; for line l10, its upper node is node k4 and its lower node is node k 5. Each node is provided with a branch control module, and the branch control modules are 5 in total and are matched with one remote positioning module. Each line is provided with a collection communication component for collecting three-phase current, and for a branch control module correspondingly arranged at a certain node, the collection communication component comprises a collection communication component (except for the node k 1) arranged on the line with the node as an upper node. For example, for node k2, the branch control module provided at node k2 includes acquisition communication components including an acquisition communication component provided on line l2 and line l 5; for node k4, the branch control module provided at node k4 includes acquisition communication components including line l10 and an acquisition communication component provided on line l 7. And as for the node k1, one end of the branch control module is connected to the power supply side, so that the branch control module arranged at the node k1 comprises a collection communication component arranged on the line l12 in addition to the collection communication components arranged on the line l4 and the line l 1.
The method is described after the entire system is described. For example, if the current of the line l10 has the phenomenon that the current of the phase B drops to zero at the current moment, and the current of the phase a and the phase C of the line l10 at the current moment has a phase a and a phase C of the previous moment with little difference, the further judgment processing is continued; an upper node of the line l10 is a node k4, a line taking the node k4 as a lower node is a line l4, an upper node of the line l10 is a node k4, other lines taking the node k4 as an upper node are lines l7, a lower node of the line l10 is a node k5, and a line taking the node k5 as an upper node includes a line l9 and a line l 11; further judging and processing as follows: if the current time B-phase current of the line l4 has a descending trend, the current time three-phase current of the line l7 is not much different from the previous time, and the current time B-phase currents of the line l9 and the line l11 are reduced to zero, it can be determined that the current time of the line l10 has a disconnection fault. After that, the specific location of the fault in the line l10 is determined by the image capturing unit in the branch control module corresponding to the node k 4.
In summary, the present invention has the following features:
1) the power distribution network disconnection fault positioning method realized by the power distribution network disconnection fault positioning system utilizes the acquisition communication component in the branch control module to acquire the current characteristic quantity on site so as to realize the positioning of the disconnection fault section.
2) The remote positioning module can comprehensively analyze and judge the field equipment, has more perfect fault monitoring function, does not need complex parameter calculation, and is theoretically not influenced by a neutral point grounding mode, so the remote positioning module has wide applicability compared with the prior art.
3) The invention carries out closed-loop verification through the branch control module and the remote control module, has definite implementation mode, more accurate judgment result and stronger economical efficiency and practicability.
4) The invention reduces the energy consumption of the equipment through hierarchical control, and the field equipment runs more reliably; through hierarchical control, unnecessary transmission of communication data and graphic image data is reduced, namely, energy loss is saved, communication flow consumption is reduced, and further, the running cost of equipment is reduced.
The method comprises the following steps:
the embodiment of the method for positioning the disconnection fault of the power distribution network, which is provided by the invention, is consistent with the method for positioning the disconnection fault of the power distribution network introduced in the system embodiment, and is not repeated herein.
Claims (10)
1. A power distribution network disconnection fault positioning method is characterized by comprising the following steps:
1) acquiring three-phase current of each section of line on the power distribution network line; the distribution network line is divided into a plurality of sections of lines by all nodes, for one section of line, the node is called as an upper node of the section of line under the condition that the upstream of the section of line is connected with the node, and the node is called as a lower node of the section of line under the condition that the downstream of the section of line is connected with the node;
2) for a certain section of line, judging whether a certain or a plurality of phase currents of the certain section of line are smaller than a set zero-dropping threshold value at the current moment, if so, defining the phase smaller than the set zero-dropping threshold value as a line-breaking phase, judging whether the difference between the current-moment non-line-breaking phase current and the last-moment non-line-breaking phase current of the certain section of line is within a set difference range, if so, defining the certain section of line as the line to be diagnosed, and executing the step 3) to further judge;
3) judging whether the following judgment conditions are met, if so, judging that the line breaking fault of the line to be diagnosed occurs at the current moment; the judgment condition includes:
the method comprises the following steps that 1, the current of the line breaking phase current of a line with an upper node of the line to be diagnosed as a lower node at the current moment is smaller than the current of the line breaking phase current at the last moment;
condition 2, when other lines except the line to be diagnosed exist with the upper node of the line to be diagnosed as the upper node, the difference between the current time current of the other lines and the current at the previous time is within a set difference range;
and 3, in the case of a line with the lower node of the line to be diagnosed as the upper node, the line-breaking phase current of the line with the lower node of the line to be diagnosed as the upper node is smaller than the set zero-dropping threshold value.
2. The method for locating the disconnection fault of the power distribution network according to claim 1, wherein after the disconnection fault of the line to be diagnosed is determined at the current moment, the line to be diagnosed is further photographed to determine the specific geographical position of the disconnection fault in the line to be diagnosed.
3. The method for positioning the disconnection fault of the power distribution network according to claim 1, wherein in the step 2), the difference between the current-time non-disconnection phase current and the previous-time non-disconnection phase current of the certain section of line is calculated by the following method: and calculating the ratio of the difference value of the current-time non-broken-line phase current and the last-time non-broken-line phase current of the certain section of line to the current-time non-broken-line phase current.
4. The method for locating the disconnection fault of the power distribution network according to claim 1, wherein in step 3), the difference between the current time and the current of the other lines at the previous time is calculated by the following method: and calculating the ratio of the difference value of the current time current of other lines and the current time current of the previous line to the current time current of other lines.
5. The method for locating the disconnection fault of the power distribution network according to claim 3 or 4, wherein the set difference range is less than 10%.
6. A power distribution network disconnection fault positioning system is characterized by comprising a remote positioning module and branch control modules corresponding to nodes on a power distribution network line, wherein each branch control module is in communication connection with the remote positioning module;
each branch control module comprises a core control unit, a line acquisition unit and a power supply unit; the power supply unit is in power supply connection with the core control unit;
the core control unit samples a connection circuit acquisition unit; if the node is a first node, the upstream of the line with the first node as a lower node is a node on the power supply side, the line acquisition unit corresponding to the node comprises a current sensor which is arranged on the line with the first node as an upper node and is used for acquiring three-phase current on the line, and a current sensor which is arranged on the line with the first node as a lower node and is used for acquiring three-phase current on the line; if the node is not the first node, the line acquisition unit corresponding to the node comprises a current sensor which is arranged on the line with the corresponding node as the upper node and is used for acquiring three-phase current on the line;
the remote positioning module comprises an industrial server and is used for realizing the power distribution network disconnection fault positioning method according to any one of claims 1 to 5 according to the acquired data.
7. The system for locating the disconnection fault of the power distribution network according to claim 6, wherein each branch control module further comprises an image acquisition unit corresponding to a node on the power distribution network line, and the image acquisition unit is used for shooting the line to be diagnosed.
8. The system of claim 6, wherein the power supply unit comprises a solar main power supply and a backup battery, and the solar main power supply is in power connection with the backup battery.
9. The system for locating the disconnection fault of the power distribution network according to claim 6, wherein each branch control module and the remote location module adopt a narrow-band internet of things communication mode.
10. The power distribution network disconnection fault location system according to any one of claims 6 to 9, wherein the remote location module further comprises a human-computer interaction unit and a graphic display unit which are both connected with the industrial server.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114895149A (en) * | 2022-07-13 | 2022-08-12 | 石家庄科林电气股份有限公司 | Power distribution network disconnection fault detection method and detection terminal |
| CN117706279A (en) * | 2024-02-05 | 2024-03-15 | 青岛鼎信通讯科技有限公司 | Phase failure fault diagnosis method for low-voltage distribution system |
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2022
- 2022-03-23 CN CN202210295420.1A patent/CN114814450A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114895149A (en) * | 2022-07-13 | 2022-08-12 | 石家庄科林电气股份有限公司 | Power distribution network disconnection fault detection method and detection terminal |
| CN114895149B (en) * | 2022-07-13 | 2022-09-30 | 石家庄科林电气股份有限公司 | Power distribution network disconnection fault detection method and detection terminal |
| CN117706279A (en) * | 2024-02-05 | 2024-03-15 | 青岛鼎信通讯科技有限公司 | Phase failure fault diagnosis method for low-voltage distribution system |
| CN117706279B (en) * | 2024-02-05 | 2024-05-24 | 青岛鼎信通讯科技有限公司 | Phase failure fault diagnosis method for low-voltage distribution system |
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