CN113437730A - Self-adaptive topology change power distribution network protection method based on edge gateway system - Google Patents
Self-adaptive topology change power distribution network protection method based on edge gateway system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/263—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of measured values
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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Abstract
The invention provides a self-adaptive topology change power distribution network protection method based on an edge gateway system. Deploying an edge gateway system at each node of a distribution network, controlling an acquisition module to acquire information and controlling a node switch to be switched on and off through a terminal controller in the system, and transmitting data through a wireless edge gateway; the method comprises the following steps: when the distribution network topology changes, the node edge gateway system acquires current data after sensing the switch variation and sends current request signals to other nodes in the distribution network, the nodes receiving the signals send the acquired current data back to the nodes with topology changes, and the nodes carry out correlation analysis on the transmitted current data and judge a new topology relation according to the correlation coefficient value; meanwhile, the fault section is judged according to the correlation coefficient value of the current data of the nodes at two ends of the line, and then the fault is isolated. The invention has the advantages that the topology change of the distribution network can be self-adapted without manual setting, and simultaneously, the problems of time delay and jitter of data wireless transmission are solved.
Description
Technical Field
The invention belongs to the technical field of relay protection of a power distribution network, and particularly relates to a self-adaptive topology change power distribution network protection method based on an edge gateway system.
Background
The power distribution network is an important basis of the energy Internet and is a key link influencing the power supply service level. With the massive access of distributed energy, higher requirements are put forward on the safety, economy and adaptability of the power distribution network.
At present, the degree of automation of a domestic power distribution network is not high, the power distribution network is mostly in a small current grounding mode, when a line fault occurs, the fault is isolated by the action of a 10kV outgoing line protection device of a transformer substation, and the power failure range is large. A centralized feeder automation mode or a sectionalizer-recloser mode is adopted in part of regions to isolate faults, but the centralized feeder automation mode needs a distribution network master station system to participate, so that the protection action time is long; the voltage/current-time recloser mode requires multiple reclosings of a breaker at an outlet of a transformer substation, and has large impact on a system. As more and more distributed power sources are plugged into a 10kV distribution network, the distribution network becomes a network with double or multiple ended power sources. On the other hand, in order to further improve the power supply reliability, a plurality of power supplies, multiple networks and even a loop closing operation mode are adopted in some important load areas. These will change the fault current distribution of the distribution network, making the centralized feeder automation and voltage/current-time recloser model described above unsuitable.
The intelligent distributed feeder automation is realized by peer-to-peer communication between power distribution terminals, information interaction is carried out, the positioning and isolation of a distribution network fault section and power supply recovery of a non-fault area are independently and quickly completed without depending on a master station. The purposes of reducing the power failure area, reducing the power failure time and reducing the power failure times are achieved, and the power supply reliability of the distribution network is greatly improved. However, the automation of the intelligent distributed feeder has higher communication requirement, the field is realized by adopting optical fiber communication, and the cost is higher. Meanwhile, most suburb and rural power lines are overhead lines, optical fibers are difficult to lay, and automation of deploying intelligent distributed feeder lines is not easy to realize.
The power distribution network shows different topological structures under different operating conditions, and can be generally divided into economic reconstruction and fault reconstruction. When the distribution network topology structure changes, the original relay protection logic of the changed part sent by the topology structure is not applicable any more.
Disclosure of Invention
The invention aims to provide a self-adaptive topology change power distribution network protection method based on an edge gateway system.
The method effectively solves the problem of relay protection logic failure caused by distribution network topology change, and simultaneously utilizes the current sequences acquired by nodes at two ends of the line to carry out correlation analysis, thereby overcoming the problem of possible false action of wireless communication caused by time delay and jitter to the traditional distribution network differential protection.
In order to achieve the purpose, the technical scheme adopted by the invention is a self-adaptive topology change power distribution network protection method based on an edge gateway system.
The edge gateway system includes: the system comprises a current transformer, a switch state acquisition module, a data memory, a node switch, a wireless edge gateway and a terminal controller;
the terminal controller is respectively connected with the current transformer, the switch state acquisition module, the data memory, the node switch and the wireless edge gateway in sequence in a wired mode;
the protection method for the self-adaptive topology change power distribution network comprises the following steps:
step 1: deploying an edge gateway system at each node position of the power distribution network, wherein the current transformer collects a real-time current sequence of the nodes and transmits the current sequence to the wireless edge gateway through a terminal controller; the switch state acquisition module acquires the real-time switch state of the node and transmits the real-time switch state to the wireless edge gateway through the terminal controller; the terminal controller records the electrical connection state of each node in the power distribution network into the data storage;
step 2: if the terminal controller detects that the real-time switch state of the node is changed from the closed state to the open state through the switch state acquisition module, the terminal controller corresponding to the node with the changed switch state analyzes the electrical connection state of the node with the changed current switch state and other nodes in the power distribution network, the terminal controller acquires real-time current sampling data with a time tag through a current transformer, transmits message request information to a wireless edge gateway corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network through the wireless edge gateway, further transmits the message request information to the terminal controller through the wireless edge gateway, and the terminal controller corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network, acquires the real-time current sampling data with the time tag through the current transformer and transmits the real-time current sampling data to the wireless edge gateway corresponding to the node with the changed switch state through the wireless edge gateway, further transmitted to the terminal controller by the wireless edge gateway;
and step 3: when a node with a changed switch state receives real-time current sampling data with a time label, which is acquired by a current transformer and sent by a wireless edge gateway, through a terminal controller corresponding to a node in a power distribution network with a disconnected electrical connection state with the node with the changed switch state, the real-time current sampling data with the time label, which is acquired by the current transformer and controlled by the terminal controller of the node with the changed switch state, is subjected to correlation analysis by intercepting data with a sampling number of N under the same time label, and a correlation coefficient is obtained;
and 4, step 4: the real-time current sampling data with the time labels, which are acquired by a current transformer and controlled by a terminal controller of a node with a change of a switch state, and the real-time current sampling data with the time labels, which are transmitted to the node with the change of the switch state by each node terminal controller in a power distribution network with the disconnected electrical connection state of the node with the change of the switch state through a wireless edge gateway, are acquired by the current transformer and sequenced, and the absolute value | r of the largest correlation coefficient is selectedijL, |; and a new electrical connection is established between the nodes of the power distribution network corresponding to the current sampling data with the maximum absolute value of the correlation coefficient, so that the topology self-adaptive identification is realized.
And 5: if the terminal controller detects an overcurrent signal of a node through the current transformer, the acquired real-time current sampling data with the time tag is transmitted to a wireless edge gateway corresponding to the node in the power distribution network electrically connected with the node detecting the overcurrent signal through the wireless edge gateway, and further transmitted to the terminal controller through the wireless edge gateway. After a node which is electrically connected with a node of a terminal controller for detecting an overcurrent signal through a current transformer receives real-time current sampling data with a time label sent by the node for detecting the overcurrent signal, the terminal controller collects the real-time current sampling data with the time label through the current transformer and carries out correlation analysis with the real-time current sampling data with the time label sent by the node for detecting the overcurrent signal through a wireless edge gateway, and carries out identification on a fault line through a correlation coefficient to obtain nodes at two ends of the fault line, and the terminal controllers of the nodes at the two ends of the fault line control node switches of the nodes at the two ends of the line to be disconnected, so that electrical isolation of the fault line is realized.
Preferably, the real-time current virtual sequence of the node in step 1 is defined as:
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, M represents the number of nodes in the power distribution network, and N represents the number of collection moments;
the positive direction of the real-time current sequence is defined as follows: if the power direction is flowing into the node through the switch, the current is defined as the positive direction; if the power direction is flowing into the switch through the node, the current is defined as the reverse direction;
Si,k,i∈[1,M],k∈[1,N]
wherein S isi,k,i∈[1,M],k∈[1,N]Showing the switch state of the ith node collected at the kth moment in the power distribution network, if Si,jIf the switching state of the ith node collected at the kth moment in the power distribution network is in a closed state, the switching state is represented as 1i,jWhen the switching state acquired at the kth moment of the ith node in the power distribution network is in an off state, M represents the number of nodes in the power distribution network, and N represents the number of acquisition moments;
flagi,j,i∈[1,M],j∈[1,M],i≠j
wherein, flagi,jRepresenting the ith node and the jth node in the distribution networkElectrical connection state of the point, if flagi,jIf the flag indicates that the ith node is connected with the jth node in the power distribution network, the ith node is connected with the jth node in the power distribution networki,j0 represents that the ith node is disconnected with the jth node in the power distribution network;
preferably, the message request information in step 2 refers to a current acquisition request signal, and the terminal controller controls the current transformer to sample current data in real time after receiving the current acquisition request signal;
the real-time current sampling data with the time tag in the step 2 is as follows:
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, k is a time label, M represents the number of nodes in the power distribution network, and N represents the number of collection moments;
preferably, the real-time current sampling data with the time length N under the same time stamp in step 3 is defined as:
Ii,k＝{Ii,1,Ii,2,...Ii,N},i∈[1,M],k∈[1,N]；
Ij,k＝{Ij，1,Ij，2,...Ij,N},j∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The real-time current sampling data which represent that the time length collected by the current transformer is controlled by the i-node terminal controller is N; i isj,k,j∈[1,M],k∈[1,N]Real-time current sampling data with time length N for representing that j node terminal controller controls current transformer to collect
The correlation analysis of the data in step 3 is as follows:
wherein the content of the first and second substances,
and
are respectively sequence Ii,kAnd Ij,kThe value range of the correlation coefficient is-1 is more than or equal to r and less than or equal to 1, when r is more than 0, the two sequences are in positive correlation, and when r is less than 0, the two sequences are in negative correlation;
preferably, the overcurrent signal in step 5 is when the collected current data satisfies the following condition
I＞I0
Wherein, I0Sampling data for real-time current detected by a terminal controller through a current transformer, I0The maximum load current for normal operation of the line.
The identification of the fault line through the correlation coefficient in the step 5 means that if the line between the node i and the node j has a fault, the power directions of the node i and the node j at two ends of the fault line are opposite, and the real-time current sequences of the node i and the node j are positively correlated, namely, the power directions are all from the node to the switch, namely, the correlation coefficient r of the current sequences at two endsi,jIs a positive value; when the line between the node i and the node j is a non-fault line, the power directions of the node i and the node j are the same, and the current sequences of the node i and the node j should be in negative correlation at the moment, namely the correlation coefficient r of the current sequences at the two endsi,jIs a negative value;
the invention has the beneficial effects that:
according to the power distribution network distributed protection method based on the self-adaptive topological change, the distributed isolation of fault lines is realized by performing correlation analysis on real-time current sequences collected at all switch nodes in the power distribution network, and the problems of data transmission delay and jitter caused by a wireless communication mode are solved. When the topological structure of the power distribution network changes due to the operation mode, the current sequences of all edge gateways are collected through the communication network and subjected to correlation analysis, the two switch nodes with the highest correlation coefficient can be identified, and new electrical connection is established, so that the self-adaptive identification of the topological structure change of the power distribution network is realized, and the difficulty that the protection logic needs to be adjusted manually due to the change of the topological structure of the power distribution network is avoided. The method adopts the current sequence to carry out correlation analysis, can effectively solve the problem of power distribution network protection caused by large-scale access of the distributed power supply to the power distribution network, overcomes the defects of the traditional current protection and the centralized distribution network protection, and solves the problem of failure of protection logic when the distribution network is reconstructed. Meanwhile, the 5G slicing technology is applied, the problems of high manufacturing cost and difficult operation and maintenance of the optical fiber can be solved, and the protection method has the advantages of high accuracy, self-adaption to topological change and convenience in operation and maintenance.
Drawings
FIG. 1: a method flow diagram of the invention;
FIG. 2: the invention provides a schematic diagram of a specific embodiment of networking operation of an edge gateway of a power distribution network;
FIG. 3: the invention provides a schematic diagram of a specific embodiment of the change of the topological structure of the power distribution network;
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention, as the invention will be described in detail, with reference to the following detailed description. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
The technical scheme adopted by the specific implementation mode of the invention is a self-adaptive topology change power distribution network protection method based on an edge gateway system.
The edge gateway system includes: the system comprises a current transformer, a switch state acquisition module, a data memory, a node switch, a wireless edge gateway and a terminal controller;
and the terminal controller is respectively connected with the current transformer, the switch state acquisition module, the data memory, the node switch and the wireless edge gateway in sequence in a wired mode.
The current transformer is characterized in that the current transformer is of the following model: LFZ-10Q
The on-off state acquisition module is characterized in that the model is as follows: DATA-7215
The data memory model is: intel2716
The node switch model is as follows: ZW32-12D
The wireless edge gateway model is as follows: AWT100
The terminal controller model is as follows: s7-300
The self-adaptive topology change power distribution network protection method comprises the following steps:
step 1: deploying an edge gateway system at each node position of the power distribution network, wherein the current transformer collects a real-time current sequence of the nodes and transmits the current sequence to the wireless edge gateway through a terminal controller; the switch state acquisition module acquires the real-time switch state of the node and transmits the real-time switch state to the wireless edge gateway through the terminal controller; the terminal controller records the electrical connection state of each node in the power distribution network into the data storage;
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, M represents the number of nodes in the power distribution network, and N represents the number of collection moments;
the positive direction of the real-time current sequence is defined as follows: if the power direction is flowing into the node through the switch, the current is defined as the positive direction; if the power direction is flowing into the switch through the node, the current is defined as the reverse direction;
Si,k,i∈[1,M],k∈[1,N]
wherein S isi,k,i∈[1,M],k∈[1,N]Showing the switch state of the ith node collected at the kth moment in the power distribution network, if Si,jIf the switching state of the ith node collected at the kth moment in the power distribution network is in a closed state, the switching state is represented as 1i,jWhen the switching state acquired at the kth moment of the ith node in the power distribution network is in an off state, M represents the number of nodes in the power distribution network, and N represents the number of acquisition moments;
flagi,j,i∈[1,M],j∈[1,M],i≠j
wherein, flagi,jIndicating the electrical connection state of the ith node and the jth node in the power distribution network, and if flagi,jIf the flag indicates that the ith node is connected with the jth node in the power distribution network, the ith node is connected with the jth node in the power distribution networki,j0 represents that the ith node is disconnected with the jth node in the power distribution network;
step 2: if the terminal controller detects that the real-time switch state of the node is changed from the closed state to the open state through the switch state acquisition module, the terminal controller corresponding to the node with the changed switch state analyzes the electrical connection state of the node with the changed current switch state and other nodes in the power distribution network, the terminal controller acquires real-time current sampling data with a time tag through a current transformer, transmits message request information to a wireless edge gateway corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network through the wireless edge gateway, further transmits the message request information to the terminal controller through the wireless edge gateway, and the terminal controller corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network, acquires the real-time current sampling data with the time tag through the current transformer and transmits the real-time current sampling data to the wireless edge gateway corresponding to the node with the changed switch state through the wireless edge gateway, further transmitted to the terminal controller by the wireless edge gateway;
in step 2, the message request information refers to a current acquisition request signal, and after receiving the current acquisition request signal, the terminal controller controls the current transformer to sample current data in real time;
the real-time current sampling data with the time tag in the step 2 is as follows:
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, k is a time label, M represents the number of nodes in the power distribution network, and N represents the number of collection moments;
and step 3: when a node with a changed switch state receives real-time current sampling data with a time label, which is acquired by a current transformer and sent by a wireless edge gateway, through a terminal controller corresponding to a node in a power distribution network with a disconnected electrical connection state with the node with the changed switch state, the real-time current sampling data with the time label, which is acquired by the current transformer and controlled by the terminal controller of the node with the changed switch state, is subjected to correlation analysis by intercepting data with a sampling number of N under the same time label, and a correlation coefficient is obtained;
in step 3, the real-time current sampling data with the time length of N under the same time tag is defined as:
Ii,k＝{Ii,1,Ii,2,...Ii,N},i∈[1,M],k∈[1,N]；
Ij,k＝{Ij，1,Ij，2,...Ij,N},j∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The real-time current sampling data which represent that the time length collected by the current transformer is controlled by the i-node terminal controller is N; i isj,k,j∈[1,M],k∈[1,N]Real-time current sampling data with time length N for representing that j node terminal controller controls current transformer to collect
The correlation analysis of the data in step 3 is as follows:
wherein the content of the first and second substances,
and
are respectively sequence Ii,kAnd Ij,kThe value range of the correlation coefficient is-1 is more than or equal to r and less than or equal to 1, when r is more than 0, the two sequences are in positive correlation, and when r is less than 0, the two sequences are in negative correlation;
and 4, step 4: the node self terminal controller with the switch state changing controls the current transformer to adoptThe method comprises the steps that a terminal controller of each node in a power distribution network with the disconnection of the electrical connection state of the collected real-time current sampling data with time labels and the node with the change of the switching state is acquired through a current transformer and sent to the correlation coefficient of the real-time current sampling data with the time labels of the node with the change of the switching state through a wireless edge gateway to be sequenced, and the absolute value | r of the maximum correlation coefficient is selectedijL, |; and a new electrical connection is established between the nodes of the power distribution network corresponding to the current sampling data with the maximum absolute value of the correlation coefficient, so that the topology self-adaptive identification is realized.
And 5: if the terminal controller detects an overcurrent signal of a node through the current transformer, the acquired real-time current sampling data with the time tag is transmitted to a wireless edge gateway corresponding to the node in the power distribution network electrically connected with the node detecting the overcurrent signal through the wireless edge gateway, and further transmitted to the terminal controller through the wireless edge gateway. After a node which is electrically connected with a node of a terminal controller for detecting an overcurrent signal through a current transformer receives real-time current sampling data with a time label sent by the node for detecting the overcurrent signal, the terminal controller collects the real-time current sampling data with the time label through the current transformer and carries out correlation analysis with the real-time current sampling data with the time label sent by the node for detecting the overcurrent signal through a wireless edge gateway, and carries out identification on a fault line through a correlation coefficient to obtain nodes at two ends of the fault line, and the terminal controllers of the nodes at the two ends of the fault line control node switches of the nodes at the two ends of the line to be disconnected, so that electrical isolation of the fault line is realized.
The overcurrent signal in step 5 indicates that the collected current data meets the following conditions
I＞I0
Wherein, I0Sampling data for real-time current detected by a terminal controller through a current transformer, I0The maximum load current for normal operation of the line.
The identification of the fault line is carried out through the correlation coefficient in the step 5, if the line between the node i and the node j occurs, the fault line is identifiedWhen the fault occurs, the power directions of the i node and the j node at two ends of the fault line are opposite, and the real-time current sequences of the i node and the j node are in positive correlation at the moment, namely, the power directions are all from the node to the switch, namely, the correlation coefficient r of the current sequences at two ends isi,jIs a positive value; when the line between the node i and the node j is a non-fault line, the power directions of the node i and the node j are the same, and the current sequences of the node i and the node j should be in negative correlation at the moment, namely the correlation coefficient r of the current sequences at the two endsi,jIs a negative value;
Taking the case that a fault occurs at point F on the line between the node 2 and the node 3 in fig. 2, the current sequences collected by the edge gateway system 1, the edge gateway system 2, and the edge gateway system 3 through the corresponding current transformers respectively after sensing the fault overcurrent signal are as follows: i is1＝{I1,1,I1,2,...,I1,N}、I2＝{I2,1,I2,2,...,I2,N}、I3＝{I3,1,I3,2,...,I3,NAnd sending the acquired current sequence to an edge gateway system of a switch node electrically connected with the switch node, namely sending the current sequence to an edge gateway system 2 by an edge gateway system 1, sending the current sequence to the edge gateway system 1 and an edge gateway system 3 by the edge gateway system 2, and sending the current sequence to the edge gateway system 2 by the edge gateway system 3. After receiving the current sequence, the terminal controller of each edge gateway system carries out correlation analysis on the current sequence and the current sequence acquired by the switch node, and as the line section between the node 1 and the node 2 is a non-fault section, the sequence I can be obtained1And sequence I2Is inversely related, the correlation coefficient r1,2Less than 0; since the line segment between node 2 and node 3 is a faulty segment, sequence I2And sequence I3Is in positive correlation with a correlation coefficient r2,3Is greater than 0; namely, the edge gateway system 2 analyzes that the fault section can be positioned at the switch node according to the fact that the correlation coefficient of the current sequence is a positive valuePoint 2 and switch node 3; the edge gateway system 2 and the edge gateway system 3 respectively control the circuit breakers K22 and K31 to be disconnected through a terminal controller, and isolation of a fault line is achieved.
Fig. 3 is a simple schematic diagram of a power distribution network topology, from which it can be obtained that the node 7 and the node 3 are electrically connected under the current operating condition, and when the system changes the operating condition, in order to improve the economy and safety of the system, the electrical connection between the node 7 and the node 3 is disconnected by a switching device, and a new electrical connection is established between the node 7 and the node 4. The initially preset parameters will no longer apply after the topology condition changes, i.e. the node 7 will perform a current sequence comparison with the node 3 before the topology change, and the node will perform a current sequence comparison with the node 4 after the topology change.
The process of the invention for adapting to the network topology change is as follows. When the edge gateway system at the node 7 detects that the node switch connected to the node 3 is actively turned off through the switch state detection module, the edge gateway system sends a current sequence request signal to the edge gateway systems (the edge gateway systems 1, 2, 4, 5, 6) at the nodes except the node 3 in the communication network. After receiving the signal, the edge gateway system at the switch node sends a section of real-time current sampling data with a length of N and time scale to the edge gateway system 7, the edge gateway system 7 performs correlation analysis after receiving the current sequences sent by each edge gateway system, and sorts the correlation coefficients of each group of current sequences, thereby identifying the current sequence with the highest absolute value of the correlation coefficient of the current sequence acquired by itself, i.e., the current sequence acquired by the switch node 4, and thus the system defines that the switch node 7 establishes a new electrical connection with the switch node 4. Through the process, the topological change is identified in a self-adaptive manner by the system without depending on human intervention when the topological structure of the distribution network changes.
It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (5)
1. A self-adaptive topology change power distribution network protection method based on an edge gateway system is characterized in that,
the edge gateway system includes: the system comprises a current transformer, a switch state acquisition module, a data memory, a node switch, a wireless edge gateway and a terminal controller;
the terminal controller is respectively connected with the current transformer, the switch state acquisition module, the data memory, the node switch and the wireless edge gateway in sequence in a wired mode;
the protection method for the self-adaptive topology change power distribution network comprises the following steps:
step 1: deploying an edge gateway system at each node position of the power distribution network, wherein the current transformer collects a real-time current sequence of the nodes and transmits the current sequence to the wireless edge gateway through a terminal controller; the switch state acquisition module acquires the real-time switch state of the node and transmits the real-time switch state to the wireless edge gateway through the terminal controller; the terminal controller records the electrical connection state of each node in the power distribution network into the data storage;
step 2: if the terminal controller detects that the real-time switch state of the node is changed from the closed state to the open state through the switch state acquisition module, the terminal controller corresponding to the node with the changed switch state analyzes the electrical connection state of the node with the changed current switch state and other nodes in the power distribution network, the terminal controller acquires real-time current sampling data with a time tag through a current transformer, transmits message request information to a wireless edge gateway corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network through the wireless edge gateway, further transmits the message request information to the terminal controller through the wireless edge gateway, and the terminal controller corresponding to the node with the changed switch state, the electrical connection state of which is the disconnected node in the power distribution network, acquires the real-time current sampling data with the time tag through the current transformer and transmits the real-time current sampling data to the wireless edge gateway corresponding to the node with the changed switch state through the wireless edge gateway, further transmitted to the terminal controller by the wireless edge gateway;
and step 3: when a node with a changed switch state receives real-time current sampling data with a time label, which is acquired by a current transformer and sent by a wireless edge gateway, through a terminal controller corresponding to a node in a power distribution network with a disconnected electrical connection state with the node with the changed switch state, the real-time current sampling data with the time label, which is acquired by the current transformer and controlled by the terminal controller of the node with the changed switch state, is subjected to correlation analysis by intercepting data with a sampling number of N under the same time label, and a correlation coefficient is obtained;
and 4, step 4: the real-time current sampling data with the time labels, which are acquired by a current transformer and controlled by a terminal controller of a node with a change of a switch state, and the real-time current sampling data with the time labels, which are transmitted to the node with the change of the switch state by each node terminal controller in a power distribution network with the disconnected electrical connection state of the node with the change of the switch state through a wireless edge gateway, are acquired by the current transformer and sequenced, and the absolute value | r of the largest correlation coefficient is selectedijL, |; a new electrical connection is established between the nodes of the power distribution network corresponding to the current sampling data with the maximum absolute value of the correlation coefficient, so that the topology self-adaptive identification is realized;
and 5: if the terminal controller detects an overcurrent signal of a node through the current transformer, the acquired real-time current sampling data with the time tag is transmitted to a wireless edge gateway corresponding to the node in the power distribution network electrically connected with the node detecting the overcurrent signal through the wireless edge gateway, and further transmitted to the terminal controller through the wireless edge gateway. After a node which is electrically connected with a node of a terminal controller for detecting an overcurrent signal through a current transformer receives real-time current sampling data with a time label sent by the node for detecting the overcurrent signal, the terminal controller collects the real-time current sampling data with the time label through the current transformer and carries out correlation analysis with the real-time current sampling data with the time label sent by the node for detecting the overcurrent signal through a wireless edge gateway, and carries out identification on a fault line through a correlation coefficient to obtain nodes at two ends of the fault line, and the terminal controllers of the nodes at the two ends of the fault line control node switches of the nodes at the two ends of the line to be disconnected, so that electrical isolation of the fault line is realized.
2. The method for protecting the distribution network based on the adaptive topology change of the edge gateway system according to claim 1, wherein the real-time current sequence of the node in step 1 is defined as:
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, M represents the number of nodes in the power distribution network, and N represents the number of collection moments;
the positive direction of the real-time current sequence is defined as follows: if the power direction is flowing into the node through the switch, the current is defined as the positive direction; if the power direction is flowing into the switch through the node, the current is defined as the reverse direction;
step 1, the real-time on-off state of the node is defined as:
Si,k,i∈[1,M],k∈[1,N]
wherein S isi,k,i∈[1,M],k∈[1,N]Showing the switch state of the ith node collected at the kth moment in the power distribution network, if Si,jIf the switching state of the ith node collected at the kth moment in the power distribution network is in a closed state, the switching state is represented as 1i,jWhen the switching state acquired at the kth moment of the ith node in the power distribution network is in an off state, M represents the number of nodes in the power distribution network, and N represents the number of acquisition moments;
step 1, the electrical connection state of each node in the power distribution network is defined as:
flagi,j,i∈[1,M],j∈[1,M],i≠j
wherein, flagi,jIndicating the electrical connection state of the ith node and the jth node in the power distribution network, and if flagi,jIf the flag indicates that the ith node is connected with the jth node in the power distribution network, the ith node is connected with the jth node in the power distribution networki,jAnd 0 represents that the ith node is disconnected from the jth node in the power distribution network.
3. The method for protecting a distribution network based on the adaptive topology change of the edge gateway system according to claim 1, wherein the message request information in step 2 refers to a current acquisition request signal, and after receiving the current acquisition request signal, the terminal controller controls a current transformer to perform real-time current data sampling;
the real-time current sampling data with the time tag in the step 2 is as follows:
Ii,k,i∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The current collected at the kth moment of the ith node in the power distribution network is represented, k is a time label, M represents the number of the nodes in the power distribution network, and N represents the number of the collection moments.
4. The method according to claim 1, wherein the real-time current sampling data with time length N under the same time tag in step 3 is defined as:
Ii,k＝{Ii,1,Ii,2,...Ii,N},i∈[1,M],k∈[1,N]；
Ij,k＝{Ij，1,Ij，2,...Ij,N},j∈[1,M],k∈[1,N]
wherein, Ii,k,i∈[1,M],k∈[1,N]The real-time current sampling data which represent that the time length collected by the current transformer is controlled by the i-node terminal controller is N; i isj,k,j∈[1,M],k∈[1,N]Real-time current sampling data with time length N for representing that j node terminal controller controls current transformer to collect
The correlation analysis of the data in step 3 is as follows:
wherein the content of the first and second substances,
and
are respectively sequence Ii,kAnd Ij,kThe value range of the correlation coefficient is-1 is more than or equal to r and less than or equal to 1, when r is more than 0, the two sequences are in positive correlation, and when r is less than 0, the two sequences are in negative correlation.
5. The method according to claim 1, wherein the overcurrent signal in step 5 refers to a current data collected when the following condition is satisfied
I＞I0
Wherein, I0Sampling data for real-time current detected by a terminal controller through a current transformer, I0The maximum load current for normal operation of the line;
the identification of the fault line through the correlation coefficient in the step 5 means that if the line between the node i and the node j has a fault, the power directions of the node i and the node j at two ends of the fault line are opposite, and the real-time current sequences of the node i and the node j are positively correlated, namely, the power directions are all from the node to the switch, namely, the correlation coefficient r of the current sequences at two endsi,jIs a positive value; when the line between the node i and the node j is a non-fault line, the power directions of the node i and the node j are the same, and the current sequences of the node i and the node j should be in negative correlation at the moment, namely the correlation coefficient r of the current sequences at the two endsi,jIs negative.
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| CN116388111A (en) * | 2023-04-18 | 2023-07-04 | 杭州欣美成套电器制造有限公司 | In-situ measurement and control protection integrated device of electric micro-grid |
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| CN115313665A (en) * | 2022-10-11 | 2022-11-08 | 国网浙江省电力有限公司宁波市北仑区供电公司 | Intelligent power distribution gateway system of power distribution station room and power distribution gateway control method |
| CN116388111A (en) * | 2023-04-18 | 2023-07-04 | 杭州欣美成套电器制造有限公司 | In-situ measurement and control protection integrated device of electric micro-grid |
| CN116388111B (en) * | 2023-04-18 | 2024-02-20 | 杭州欣美成套电器制造有限公司 | In-situ measurement and control protection integrated device of electric micro-grid |
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