Power failure monitoring and early warning method for power distribution network

Abstract

The invention belongs to the technical field of power distribution network operation management, and particularly relates to a power distribution network power failure monitoring and early warning method. Comprising the following steps: constructing a power distribution network switch matrix, establishing a power distribution network switch state measurement data confidence coefficient matrix based on the power distribution network switch matrix, and sequentially judging all power distribution network feeder lines based on each row of the power distribution network switch matrix; according to the power distribution network switch state measurement data confidence coefficient matrix and the power distribution network real-time state data, analyzing and determining an area where a power distribution fault is located; and according to the power distribution network feeder line cutting condition, analyzing the cutting probability of each area, and obtaining a power distribution network area power failure analysis result. The invention mainly relates to a power distribution network power failure monitoring and early warning method, which performs prediction and early warning on power distribution network fault information and possibly caused power failure events through real-time measurement data, a power distribution network switch state of a line switch topology and confidence analysis of the power distribution network switch state.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network operation management, and in particular relates to a distribution network power outage monitoring and early warning method. Background Art

[0002] In order to ensure the stable and healthy operation of the distribution network system and avoid various problems such as overload and circuit breakage that affect the overall stability of the power supply and distribution system, various types of switch devices or terminals are set up in the distribution network to deal with local faults through overcurrent protection, active fault isolation and other methods to prevent the further expansion of the fault. The above-mentioned switch devices or terminals will cause the distribution network topology structure to change in real time during operation. Obtaining the distribution network measurement information and analyzing the data information of the above-mentioned switch devices or terminals are the basis for various tasks such as analysis and evaluation of the current operating status of the distribution network. Since various types of faults and unexpected situations are inevitable during the operation of the distribution network, the above-mentioned switch equipment or terminals need to perform corresponding on-off operations based on the measurement data of the nodes in a timely and accurate manner during operation to avoid the continued propagation of the fault. In this process, planned or unplanned power outages may occur. In the process of distribution network operation and management, it is necessary to effectively analyze them in order to facilitate power supply restoration planning and power outage emergency handling. Summary of the invention

[0003] The purpose of the present invention is to provide a method, based on actual needs, for analyzing the fault status of a distribution network caused by various reasons based on the real-time topological structure of the distribution network when the switch status of the distribution network changes in real time, and predicting and inferring possible power outage areas.

[0004] To achieve the above purpose, the present invention adopts the following technical solution.

[0005] A power distribution network outage monitoring and early warning method comprises the following steps:

[0006] Step (1): Establish the distribution network feeder credibility matrix

[0007] Constructing a distribution network switch matrix, wherein the distribution network switch matrix is ​​composed of rows formed by distribution network feeder loops and a state matrix composed of individual distribution network switches on the distribution network feeder loops as columns; establishing a distribution network switch state measurement data confidence matrix based on the distribution network switch matrix, and judging all distribution network feeders in turn based on each row of the distribution network switch matrix;

[0008] Step (2), determining the area where the distribution fault is located based on the confidence matrix of the distribution network switch state measurement data and the distribution network real-time state data analysis;

[0009] Based on the distribution network feeder topology structure, the distribution network feeder information is obtained. For any distribution network feeder i, the corresponding distribution network feeder confidence ω is extracted. i, then the probability of correct execution of the protection action of the dual main protection can be expressed as p i =ω i p1p2, where p1 and p2 are the efficiencies of the two nodes of the dual-connection master protection;

[0010] If the distribution network feeder i performs protection action based on the above probability, the faulty feeder will be isolated and cut off, and the power outage range is within the corresponding feeder protection section, and then go to step (3);

[0011] If the distribution network feeder i does not perform protection action based on the above probability, the backup protection is started, and the longitudinal protection of the adjacent line is started at the same time, and then go to step (4);

[0012] Step (3), distribution network feeder secondary protection status analysis, specifically includes:

[0013] For the non-fault line j adjacent to the distribution network feeder i, the probability of being de-energized by the secondary protection can be expressed as p j =ω j p ij ; where ω j is the confidence of the node where the secondary protection is located, p ij It refers to the probability that the secondary protection in non-fault line j is affected by the double main protection device of distribution network feeder i and malfunctions;

[0014] Step (4): Analyze the probability of each area being cut off according to the distribution network feeder cut off situation, and obtain the distribution network regional power outage analysis result.

[0015] To further improve or implement the above-mentioned distribution network power outage monitoring and early warning method, the step (1) specifically includes:

[0016] A1. Assume that the initial confidence of the measured data of each distribution network switch is 0, and define the input measured data of any distribution network feeder a as The output measurement data of distribution network feeder a is: The allowable error corresponding to the distribution network feeder a is δ, and the measurement data of two adjacent distribution network switches on the distribution network feeder a are and

[0017] A2. Analyze the confidence of the measured data of all adjacent distribution network switches based on the aforementioned distribution network switch matrix. If Then the measurement data and The confidence value of the measurement data of the corresponding distribution network switch is increased by one, otherwise it remains unchanged until the confidence calculation of the measurement data of all distribution network switches is completed;

[0018] A2. Based on the rows of the aforementioned distribution network switch matrix, confidence analysis is performed on all the distribution network feeder input and output measurement data. If Then and The confidence values ​​of the measured data corresponding to all the distribution network switches are increased by one, otherwise they remain unchanged, until the confidence analysis of the measured data of all the distribution network feeder input and output associated distribution network switches is completed;

[0019] A3. Search for the remaining distribution network switches with a confidence of 0 in the distribution network switch matrix, and update them based on the corresponding measurement values ​​and measurement data of the distribution network switch with the highest confidence among the two most adjacent distribution network switches; search for the confidence and measurement data values ​​of the distribution network switches on the input and output sides of the distribution network feeder. If the input and output of the distribution network feeder do not match, delete the measurement value with the lowest confidence, and update based on the alignment of the measurement values ​​and confidence of the remaining distribution network switches;

[0020] A4. Repeat steps A2 to A3 until the confidence of each distribution network switch in the distribution network switch matrix remains unchanged, or the overall confidence is not lower than the credible threshold, or the overall confidence change rate is lower than the preset threshold, then stop updating;

[0021] A5. Establish and update the confidence matrix of the distribution network switch status measurement data based on the final results.

[0022] Further improvement or specific implementation of the above-mentioned distribution network power outage monitoring and early warning method, for the distribution network switch monitoring terminal, the confidence of the control group composed of the terminal and its preceding terminal is jointly expressed, and the confidence of the ith distribution network switch monitoring terminal represented by the control group is used Among them C i ′ refers to the true or false value of whether the i-th distribution network switch monitoring terminal detects the overcurrent data. If the overcurrent data is detected, then C i ′=1, otherwise C i ′=0.

[0023] To further improve or implement the above-mentioned distribution network power outage monitoring and early warning method, for the distribution network transformer monitoring terminal, for each port, analyze the true and false values ​​of the fault monitoring results of all the distribution network transformer monitoring terminals therein; if there is only one distribution network transformer monitoring terminal in the terminal, or the number of terminals corresponding to the true and false values ​​of the fault monitoring results in the port are equal or the number difference does not exceed the preset threshold, then the confidence of these distribution network transformer monitoring terminals is kept unchanged; if the number difference of the distribution network transformer monitoring terminals corresponding to the true and false values ​​of the fault monitoring structure in the port exceeds the preset threshold, then the confidence of the distribution network transformer monitoring terminal with a larger number is increased, and the confidence of the distribution network transformer monitoring terminal with a smaller number is reduced.

[0024] A further improvement or specific implementation of the above-mentioned distribution network power outage monitoring and early warning method further includes a step for constructing a distribution network feeder association matrix, specifically:

[0025] Based on the distribution network feeder topology, the distribution network feeder association matrix is ​​generated, and the association attribute c between the injection current of the distribution network feeder m and the current from the feeder switch n to the fault node is defined. mn , c mn =1or0,c mn =1 indicates a direct correlation between the two, c mn =0 means there is no correlation between the two, and the correlation matrix from the distribution network feeder to the fault node is obtained. Based on the distribution network measurement information, the switch state matrix of the distribution network is established by obtaining the closing state information of each switch. where k mn Indicates the closed state of the nth distribution switch on the distribution network feeder m. If it is closed, k mn =1, if it is disconnected, then k mn =0; by multiplying the distribution network line topology association matrix with the distribution network switch state matrix, the distribution network feeder association matrix can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the power outage monitoring and early warning method of the distribution network. DETAILED DESCRIPTION

[0027] The present application mainly relates to a distribution network power outage monitoring and early warning method, which predicts and warns distribution network fault information and possible power outage events through real-time measurement data and distribution network switch status and confidence analysis of line switch topology.

[0028] The present invention is described in detail below in conjunction with specific embodiments.

[0029] The main process of a distribution network power outage monitoring and early warning method of the present application is as follows: Figure 1 As shown, it specifically includes the following steps:

[0030] Step (1): Establish the distribution network feeder credibility matrix

[0031] Constructing a distribution network switch matrix, wherein the distribution network switch matrix is ​​composed of rows formed by distribution network feeder loops and a state matrix composed of individual distribution network switches on the distribution network feeder loops as columns;

[0032] Establish a confidence matrix of the distribution network switch state measurement data, and make judgments on all distribution network feeders in turn based on each row of the distribution network switch matrix, which specifically includes the following steps:

[0033] A1. Assume that the initial confidence of the measured data of each distribution network switch is 0, and define the input measured data of any distribution network feeder a as The output measurement data of distribution network feeder a is: The allowable error corresponding to the distribution network feeder a is δ, and the measurement data of two adjacent distribution network switches on the distribution network feeder a are and

[0034] A2. Analyze the confidence of the measured data of all adjacent distribution network switches based on the aforementioned distribution network switch matrix. If Then the measurement data and The confidence value of the measurement data of the corresponding distribution network switch is increased by one, otherwise it remains unchanged until the confidence calculation of the measurement data of all distribution network switches is completed;

[0035] A2. Based on the rows of the aforementioned distribution network switch matrix, confidence analysis is performed on all the distribution network feeder input and output measurement data. If Then and The confidence values ​​of the measured data corresponding to all the distribution network switches are increased by one, otherwise they remain unchanged, until the confidence analysis of the measured data of all the distribution network feeder input and output associated distribution network switches is completed;

[0036] A3. Search for the remaining distribution network switches with a confidence of 0 in the distribution network switch matrix, and update them based on the corresponding measurement values ​​and measurement data of the distribution network switch with the highest confidence among the two most adjacent distribution network switches; search for the confidence and measurement data values ​​of the distribution network switches on the input and output sides of the distribution network feeder. If the input and output of the distribution network feeder do not match, delete the measurement value with the lowest confidence, and update based on the alignment of the measurement values ​​and confidence of the remaining distribution network switches;

[0037] A4. Repeat steps A2 to A3 until the confidence of each distribution network switch in the distribution network switch matrix remains unchanged, or the overall confidence is not lower than the credible threshold, or the overall confidence change rate is lower than the preset threshold, then stop updating;

[0038] A5. Establish and update the confidence matrix of the distribution network switch status measurement data based on the final results;

[0039] In particular, in the confidence calculation process, in addition to traditional distribution network switches, various distribution network switch monitoring terminals, distribution network transformer monitoring terminals and other control terminals are also involved. The above-mentioned terminals also act as control equipment in the distribution network feeder control process. Their credibility is mainly affected by their own performance and the current transmission process during the fault. For common distribution network switch monitoring terminals, under normal circumstances, when the current impact caused by the fault reaches a distribution network switch monitoring terminal, theoretically, all the preceding distribution network switch monitoring terminals located in the overcurrent direction monitored by the terminal should monitor the overcurrent data before the terminal. Considering that the confidence of an independent terminal is difficult to quantify accurately, this application considers using the confidence of a control group composed of the terminal and its preceding terminals to jointly represent the confidence of the control group. The confidence of the control group can be represented by the ratio of the number of terminals that monitor the overcurrent data to the total number of terminals in the control group. The confidence of the i-th distribution network switch monitoring terminal represented by the control group is Among them C i ′ refers to the true or false value of whether the i-th distribution network switch monitoring terminal detects the overcurrent data. If the overcurrent data is detected, then C i ′=1, otherwise C i ′=0;

[0040] This joint representation method integrates the decentralized confidence of each independent terminal into the feeder topology structure as a whole, which can effectively simplify the analysis process;

[0041] Similarly, for the distribution network transformer monitoring terminal, the fault monitoring signals of all distribution network transformer monitoring terminals located in the same port should be consistent. Therefore, the confidence of the distribution network transformer monitoring terminal in the same port can be expressed by the consistency of the terminal with other terminals in the port. Specifically, all distribution network transformer monitoring terminals can be given the same initial confidence according to the actual precision and accuracy of the distribution network transformer monitoring terminal. In each confidence update process, for each port, the true and false values ​​of the fault monitoring results of all distribution network transformer monitoring terminals in it are analyzed. If there is only one distribution network transformer monitoring terminal in the terminal, or the number of terminals corresponding to the true and false values ​​of the fault monitoring results in the port is equal or the number difference does not exceed the preset threshold, then the confidence of these distribution network transformer monitoring terminals is kept unchanged. If the number difference of the distribution network transformer monitoring terminals corresponding to the true and false values ​​of the fault monitoring structure in the port exceeds the preset threshold, the confidence of the distribution network transformer monitoring terminal with a larger number is increased, and the confidence of the distribution network transformer monitoring terminal with a smaller number is reduced.

[0042] Step (2), determine the distribution fault area according to the confidence matrix of the distribution network switch state measurement data and the real-time state data of the distribution network; obtain the distribution network feeder information based on the distribution network feeder topology structure, and for any distribution network feeder i, extract the corresponding distribution network feeder confidence ω i Based on the relevant regulations of the automatic safety protection device of the distribution network, the distribution network feeder needs to be equipped with double main protection devices and necessary secondary protection to ensure fault isolation as much as possible. The probability of correct execution of the protection action of the double main protection can be expressed as p i =ω i p1p2, where p1 and p2 are the efficiencies of the two nodes of the dual-connection master protection;

[0043] If the distribution network feeder i performs protection action based on the above probability, the faulty feeder will be isolated and cut off, and the power outage range is within the corresponding feeder protection section, and then go to step (3);

[0044] If the distribution network feeder i does not perform protection action based on the above probability, the backup protection is started, and the longitudinal protection of the adjacent line is started at the same time, and then go to step (4);

[0045] Step (3), the secondary protection section is usually set in the line adjacent to the protected distribution network feeder i, to ensure that when the double main protection device fails, the secondary fault is isolated and removed through the abnormal measurement data of the adjacent line; under normal circumstances, when the double main protection device correctly performs the protection action, the secondary protection device does not need to perform other operations, but because the secondary protection is a cross-segment protection, the change of electrical measurement data caused by the action process of the next-level double main protection device will directly affect the secondary protection device, resulting in the secondary protection device may be erroneously executed, so that the adjacent line of the distribution network feeder i is erroneously removed, thereby causing the expansion of the power outage area; therefore, in order to more accurately analyze the power outage scope caused by the distribution area fault, it is necessary to further analyze it, specifically:

[0046] For the non-fault line j adjacent to the distribution network feeder i, the probability of being de-energized by the secondary protection can be expressed as p j =ω j p ij ; where ω j is the confidence of the node where the secondary protection is located, p ij It refers to the probability that the secondary protection in non-fault line j is affected by the double main protection device of distribution network feeder i and malfunctions; similarly, the probability that the upper level non-fault line j+1 of non-fault line j is de-energized can also be further calculated based on this method, but it can usually be ignored;

[0047] Step (4): Analyze the probability of each area being cut off according to the distribution network feeder cut off situation, and obtain the distribution network regional power outage analysis result.

[0048] In particular, in order to further improve the efficiency of distribution network feeder protection and optimize the distribution network operation process, the present application also includes steps for constructing a distribution network feeder association matrix, specifically:

[0049] Based on the distribution network feeder topology, the distribution network feeder association matrix is ​​generated, and the association attribute c between the injection current of the distribution network feeder m and the current from the feeder switch n to the fault node is defined. mn , c mn =1or0,c mn =1 indicates a direct correlation between the two, c mn =0 means there is no correlation between the two, and the correlation matrix from the distribution network feeder to the fault node is obtained. Based on the distribution network measurement information, the switch state matrix of the distribution network is established by obtaining the closing state information of each switch. where k mn Indicates the closed state of the nth distribution switch on the distribution network feeder m. If it is closed, k mn =1, if it is disconnected, then k mn =0; by multiplying the distribution network line topology association matrix with the distribution network switch state matrix, the distribution network feeder association matrix can be obtained.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A distribution network power outage monitoring and early warning method, characterized in that: The steps include: (1) Establishing the distribution network feeder credibility matrix Constructing a distribution network switch matrix, wherein the distribution network switch matrix is ​​composed of rows formed by distribution network feeder loops and a state matrix composed of individual distribution network switches on the distribution network feeder loops as columns; establishing a distribution network switch state measurement data confidence matrix based on the distribution network switch matrix, and judging all distribution network feeders in turn based on each row of the distribution network switch matrix; (2) Determine the area where the distribution fault is located based on the confidence matrix of the distribution network switch status measurement data and the real-time status data of the distribution network; Based on the distribution network feeder topology structure, the distribution network feeder information is obtained. For any distribution network feeder i, the corresponding distribution network feeder confidence ω is extracted. i , then the probability of correct execution of the protection action of the dual main protection can be expressed as p i =ω i p1p2, where p1 and p2 are the efficiencies of the two nodes of the dual-connection master protection; If the distribution network feeder i performs protection action based on the above probability, the faulty feeder will be isolated and cut off, and the power outage range is within the corresponding feeder protection section, and then go to step (3); If the distribution network feeder i does not perform protection action based on the above probability, the backup protection is started, and the longitudinal protection of the adjacent line is started at the same time, and then go to step (4); (3) Analysis of the secondary protection status of distribution network feeders, including: For the non-fault line j adjacent to the distribution network feeder i, the probability of being de-energized by the secondary protection can be expressed as p j =ω j p ij ; where ω j is the confidence of the node where the secondary protection is located, p ij It refers to the probability that the secondary protection in non-fault line j is affected by the double main protection device of distribution network feeder i and malfunctions; (4) According to the distribution network feeder removal situation, the probability of each area being cut off is analyzed to obtain the distribution network regional power outage analysis results.

2. The power distribution network outage monitoring and early warning method according to claim 1 is characterized in that: The step (1) specifically comprises: A1. Assume that the initial confidence of the measured data of each distribution network switch is 0, and define the input measured data of any distribution network feeder a as The output measurement data of distribution network feeder a is: The allowable error corresponding to the distribution network feeder a is δ, and the measurement data of two adjacent distribution network switches on the distribution network feeder a are and A2. Analyze the confidence of the measured data of all adjacent distribution network switches based on the aforementioned distribution network switch matrix. If Then the measurement data and The confidence value of the measurement data of the corresponding distribution network switch is increased by one, otherwise it remains unchanged until the confidence calculation of the measurement data of all distribution network switches is completed; A2. Based on the rows of the aforementioned distribution network switch matrix, confidence analysis is performed on all the distribution network feeder input and output measurement data. If Then and The confidence values ​​of the measured data corresponding to all the distribution network switches are increased by one, otherwise they remain unchanged, until the confidence analysis of the measured data of all the distribution network feeder input and output associated distribution network switches is completed; A3. Search for the remaining distribution network switches with a confidence of 0 in the distribution network switch matrix, and update them based on the corresponding measurement values ​​and measurement data of the distribution network switch with the highest confidence among the two most adjacent distribution network switches; search for the confidence and measurement data values ​​of the distribution network switches on the input and output sides of the distribution network feeder. If the input and output of the distribution network feeder do not match, delete the measurement value with the lowest confidence, and update based on the alignment of the measurement values ​​and confidence of the remaining distribution network switches; A4. Repeat steps A2 to A3 until the confidence of each distribution network switch in the distribution network switch matrix remains unchanged, or the overall confidence is not lower than the credible threshold, or the overall confidence change rate is lower than the preset threshold, then stop updating; A5. Establish and update the confidence matrix of the distribution network switch status measurement data based on the final results.

3. The power distribution network outage monitoring and early warning method according to claim 1 is characterized in that: For the distribution network switch monitoring terminal, the confidence of the control group composed of the terminal and its preceding terminal is used for joint representation. Then the confidence of the ith distribution network switch monitoring terminal represented by the control group is Among them C i ′ refers to the true or false value of whether the i-th distribution network switch monitoring terminal detects the overcurrent data. If the overcurrent data is detected, then C i ′=1, otherwise C i ′=0.

4. The power distribution network outage monitoring and early warning method according to claim 1 is characterized in that: For the distribution network transformer monitoring terminal, for each port, the true and false values ​​of the fault monitoring results of all the distribution network transformer monitoring terminals in it are analyzed. If there is only one distribution network transformer monitoring terminal in the terminal, or the number of terminals corresponding to the true and false values ​​of the fault monitoring results in the port is equal or the number difference does not exceed the preset threshold, then the confidence of these distribution network transformer monitoring terminals is kept unchanged. If the number difference of the distribution network transformer monitoring terminals corresponding to the true and false values ​​of the fault monitoring structure in the port exceeds the preset threshold, the confidence of the distribution network transformer monitoring terminal with a larger number is increased, and the confidence of the distribution network transformer monitoring terminal with a smaller number is reduced.

5. The power distribution network outage monitoring and early warning method according to claim 1 is characterized in that: It also includes steps for constructing a distribution network feeder correlation matrix, specifically: Based on the distribution network feeder topology, the distribution network feeder association matrix is ​​generated, and the association attribute c between the injection current of the distribution network feeder m and the current from the feeder switch n to the fault node is defined. mn , c mn =1or0,c mn =1 indicates a direct correlation between the two, c mn =0 means there is no correlation between the two, and the correlation matrix from the distribution network feeder to the fault node is obtained. Based on the distribution network measurement information, the switch state matrix of the distribution network is established by obtaining the closing state information of each switch. where k mn Indicates the closed state of the nth distribution switch on the distribution network feeder m. If it is closed, k mn =1, if it is disconnected, then k mn =0; by multiplying the distribution network line topology association matrix with the distribution network switch state matrix, the distribution network feeder association matrix can be obtained.

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