A method and apparatus for power supply reliability analysis of power grid end users

Abstract

This invention relates to a method and apparatus for analyzing the power supply reliability of power grid end users, comprising: obtaining the switch sets of each end user and the switch sets of each component based on the node switch matrix of a low-voltage distribution network system; and analyzing the power supply reliability of each end user based on the intersection of the switch sets of each end user and the switch sets of each component. This technical solution comprehensively considers the impact of switch failures in low-voltage distribution systems on the reliability indicators of end users, analyzes the power supply reliability of end users, and can propose reasonable solutions for practical engineering, thus having significant practical application value.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and specifically to a method and apparatus for analyzing the power supply reliability of power grid end users. Background Technology

[0002] As a crucial public infrastructure directly serving electricity users, the power distribution network has played a vital role in the rapid development of the economy and society. Through long-term and continuous construction, the distribution network is gradually evolving to a higher level. Currently, research on distribution network reliability assessment primarily focuses on high- and medium-voltage users, failing to truly extend to low-voltage end-users. Because faults in medium- and high-voltage distribution systems supplying power to high- and medium-voltage users have a wide impact range, various switching devices in the system must be able to operate correctly with a high probability in the event of a fault to quickly and accurately disconnect the fault and prevent its spread. Therefore, the failure rate of switching devices in medium- and high-voltage distribution systems is extremely low, and their impact on the reliability of power supply to high- and medium-voltage users is negligible. However, low-voltage distribution network systems have completely different characteristics from high- and medium-voltage distribution network systems. Due to the smaller fault range of low-voltage distribution systems supplying power to end-users, and the inconsistent quality of distribution protection equipment, it is impossible to guarantee the safe and reliable disconnection of faulty equipment in the event of a fault. This makes them unsuitable for low-voltage distribution network systems, leading to certain errors in the analysis results and ultimately failing to accurately analyze the power supply reliability of end-users. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method and apparatus for power supply reliability analysis of power grid end users. For end-user reliability analysis that needs to consider switch failure, the method determines the set of switches included in the shortest path between each end user and each component and the distribution transformer based on the node switch matrix. Then, based on the relationship between the switch sets of each end user and each component, the reliability index of each end user is calculated based on the switch failure rate, thereby analyzing the power supply reliability of the end users.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides a method for power supply reliability analysis for power grid end users, the improvement of which includes:

[0006] Based on the node switch matrix of the low-voltage distribution network system, obtain the switch set of each end user and the switch set of each component;

[0007] The power supply reliability of each end user is analyzed based on the intersection of the switch set of each end user and the switch set of each component.

[0008] Preferably, the node switch matrix M of the low-voltage distribution network system is determined by the following formula:

[0009]

[0010] In the formula, i and j are the node numbers of the nodes in the network topology of the low-voltage distribution network system, i,j∈[1,N], and N is the node number of the last node in the network topology of the low-voltage distribution network system.

[0011] When i≥j or i<j, j≠i+1, M ij =0;

[0012] When i < j, j = i + 1 and there is no switching device between the i-th node and the j-th node, M ij =1;

[0013] When i < j, j = i + 1 and there is a switching device between the i-th node and the j-th node, M ij Let be the name of the switching device between the i-th node and the j-th node.

[0014] Preferably, the acquisition of the switch sets of each end user and the switch sets of each component based on the node switch matrix of the low-voltage distribution network system includes:

[0015] The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

[0016] The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer.

[0017] The component is a switchgear or line in a low-voltage power distribution network system.

[0018] Preferably, the analysis of the power supply reliability of each end user based on the intersection of the switch set of each end user and the switch set of each component includes:

[0019] Step (1) Initialize h = s = 1;

[0020] Step (2) Initialize the iteration count r = 1 and set T h,r =0 and D h,r =0;

[0021] Step (3) Determine whether s is greater than N D If so, then output T. h,r and D h,r If not, proceed to steps (5) and (6); otherwise, proceed to step (4).

[0022] Step (4) Update T based on the switch failure rate of the switching device, according to the intersection of the switch set of the h-th terminal user and the switch set of the s-th element. h,r and D h,r Let s = s + 1, r = r + 1 and return to step (3);

[0023] Step (5) Determine whether h is greater than N. L If yes, then end the operation; otherwise, set h = h + 1, s = 1 and return to step (2).

[0024] Step (6) If T h,r Less than α and D h,r If the value is less than β, output "The power supply reliability of the h-th terminal user is high"; otherwise, output "The power supply reliability of the h-th terminal user is poor".

[0025] Among them, T h,r Let D be the average number of power outages per year for the h-th terminal user corresponding to the r-th iteration. h,r Let α be the average annual power outage time for the h-th terminal user corresponding to the r-th iteration, α be a preset threshold for the average annual power outage frequency for each terminal user, and β be a preset threshold for the average annual power outage time for each terminal user, where h∈[1,N]. L ],s,r∈[1,N D ], N L N represents the total number of end users in a low-voltage distribution network system. D This refers to the total number of components in a low-voltage distribution network system.

[0026] Furthermore, step (4) includes:

[0027] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element is equal to the switch set of the s-th element, then update T according to the following formula. h,r and D h,r :

[0028]

[0029] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by one element, then update T according to the following formula. h,r and D h,r :

[0030]

[0031] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by two elements, then update T according to the following formula. h,r and D h,r :

[0032]

[0033] Among them, T h,r-1 Let D be the average number of power outages per year for the h-th terminal user corresponding to the (r-1)-th iteration. h,r-1 Let λ be the average annual power outage time for the h-th terminal user corresponding to the (r-1)-th iteration. s Let μ be the failure rate of the s-th component. s Let p be the repair rate of the s-th element. 1,s p represents the probability of failure of the upstream protective switch adjacent to component s to operate after component s fails. 2,s The probability of failure of the upstream protection switch adjacent to the current input terminal of the transmission line after component s fails is given. The upstream protection switch is the protection switch located between the current input terminal of the transmission line and component s.

[0034] This invention provides a power supply reliability analysis device for power grid end users, the improvement of which is that it includes:

[0035] The acquisition module is used to acquire the switch sets of each end user and the switch sets of each component based on the node switch matrix of the low-voltage distribution network system.

[0036] The analysis module is used to analyze the power supply reliability of each end user based on the intersection of the switch set of each end user and the switch set of each component;

[0037] Preferably, the node switch matrix M of the low-voltage distribution network system is determined by the following formula:

[0038]

[0039] In the formula, i and j are the node numbers of the nodes in the network topology of the low-voltage distribution network system, i,j∈[1,N], and N is the node number of the last node in the network topology of the low-voltage distribution network system.

[0040] When i≥j or i<j, j≠i+1, M ij =0;

[0041] When i < j, j = i + 1 and there is no switching device between the i-th node and the j-th node, M ij =1;

[0042] When i < j, j = i + 1 and there is a switching device between the i-th node and the j-th node, M ij Let be the name of the switching device between the i-th node and the j-th node.

[0043] Preferably, the acquisition module is specifically used for:

[0044] The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

[0045] The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer.

[0046] The component is a switchgear or line in a low-voltage power distribution network system.

[0047] Preferably, the analysis module includes:

[0048] An initialization unit is used to initialize h = s = 1;

[0049] The assignment unit is used to initialize the iteration count r = 1 and set T. h,r =0 and D h,r =0;

[0050] The first judgment unit is used to determine whether s is greater than N. D If so, then output T. h,r and D h,r If no, then execute the second judgment unit and the analysis unit; if not, then execute the calculation unit.

[0051] The calculation unit is used to update T based on the switch failure rate of the switching equipment, according to the intersection of the switch set of the h-th end user and the switch set of the s-th element. h,r and D h,r Let s = s + 1, r = r + 1 and return to the first judgment unit;

[0052] The second judgment unit is used to determine whether h is greater than N. L If yes, then end the operation; otherwise, set h = h + 1, s = 1 and return to the assignment unit.

[0053] Analysis unit, used if T h,r Less than α and D h,r If the value is less than β, output "The power supply reliability of the h-th terminal user is high"; otherwise, output "The power supply reliability of the h-th terminal user is poor".

[0054] Among them, T h,r Let D be the average number of power outages per year for the h-th terminal user corresponding to the r-th iteration. h,r Let α be the average annual power outage time for the h-th terminal user corresponding to the r-th iteration, α be a preset threshold for the average annual power outage frequency for each terminal user, and β be a preset threshold for the average annual power outage time for each terminal user, where h∈[1,N]. L],s,r∈[1,N D ], N L N represents the total number of end users in a low-voltage distribution network system. D This refers to the total number of components in a low-voltage distribution network system.

[0055] Furthermore, the computing unit is specifically used for:

[0056] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element is equal to the switch set of the s-th element, then update T according to the following formula. h,r and D h,r :

[0057]

[0058] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by one element, then update T according to the following formula. h,r and D h,r :

[0059]

[0060] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by two elements, then update T according to the following formula. h,r and D h,r :

[0061]

[0062] Among them, T h,r-1 Let D be the average number of power outages per year for the h-th terminal user corresponding to the (r-1)-th iteration. h,r-1 Let λ be the average annual power outage time for the h-th terminal user corresponding to the (r-1)-th iteration. s Let μ be the failure rate of the s-th component. s Let p be the repair rate of the s-th element. 1,s p represents the probability of failure of the upstream protective switch adjacent to component s to operate after component s fails. 2,s The probability of failure of the upstream protection switch adjacent to the current input terminal of the transmission line after component s fails is given. The upstream protection switch is the protection switch located between the current input terminal of the transmission line and component s.

[0063] Compared with the closest existing technology, the present invention has the following advantages:

[0064] The technical solution provided by this invention obtains the switch sets of each end user and the switch sets of each component based on the node switch matrix of the low-voltage distribution network system; the power supply reliability index of each end user is determined based on the intersection of the switch sets of each end user and the switch sets of each component; the node switch matrix established by this invention can effectively reflect the network topology containing multi-level protection devices, which is convenient for characterizing the network topology of the low-voltage distribution system and has universality; the impact of component failure on the power supply reliability of end users is judged based on the intersection of the switch device sets, and the analysis process is clear, the calculation speed is fast, and the efficiency is high.

[0065] The technical solution provided by this invention also comprehensively considers the impact of the failure rate of switching equipment in low-voltage power distribution systems on the reliability index of end users in the power supply reliability analysis. The obtained index has high accuracy and can provide reasonable solutions for actual engineering projects, which has important practical application significance. Attached Figure Description

[0066] Figure 1 This is a flowchart of a power supply reliability analysis method for power grid end users;

[0067] Figure 2 This is a network topology diagram of the low-voltage power distribution system in an embodiment of the present invention;

[0068] Figure 3 This is a flowchart of the power supply reliability calculation method for power grid end users in this embodiment of the invention;

[0069] Figure 4 This is a structural diagram of a power supply reliability analysis device for power grid end users. Detailed Implementation

[0070] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] To address the shortcomings in current methods for analyzing the reliability of power supply to end users in power distribution networks, and their inability to consider the problem of switch failures, this invention provides a method for analyzing the power supply reliability of power grid end users, such as... Figure 1 As shown, it includes:

[0073] Step 101: Obtain the switch set of each end user and the switch set of each component based on the node switch matrix of the low-voltage distribution network system;

[0074] Step 102: Analyze the power supply reliability of each end user based on the intersection of the switch set of each end user and the switch set of each component.

[0075] Preferably, the node switch matrix M of the low-voltage distribution network system is determined by the following formula:

[0076]

[0077] In the formula, i and j are the node numbers of the nodes in the network topology of the low-voltage distribution network system, i,j∈[1,N], and N is the node number of the last node in the network topology of the low-voltage distribution network system.

[0078] When i≥j or i<j, j≠i+1, M ij =0;

[0079] When i < j, j = i + 1 and there is no switching device between the i-th node and the j-th node, M ij =1;

[0080] When i < j, j = i + 1 and there is a switching device between the i-th node and the j-th node, M ij Let be the name of the switching device between the i-th node and the j-th node.

[0081] In embodiments of the present invention, a depth-first search topology numbering method is used to divide the network topology of a low-voltage distribution network system into nodes and assign them numbers, such as... Figure 2 This is a network topology diagram of a low-voltage power distribution system containing 12 nodes and 6 end users. All end nodes in this system are end users. The root node 0 is the distribution transformer, and Si represents protective switching equipment. S1 represents primary protection, S2–S4 represent secondary protection, and S5–S6 represent secondary protection. 10 For Level 3 protection, a node switch matrix is ​​established based on the network topology of the low-voltage distribution network:

[0082]

[0083] Preferably, the method for obtaining the switch sets of each end user and each component based on the node switch matrix of the low-voltage distribution network system includes:

[0084] The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

[0085] The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer.

[0086] Among them, the components are switching equipment or lines in low-voltage distribution network systems.

[0087] In an embodiment of the present invention, the process of obtaining the switch set of the terminal user is as follows: Based on the node switch matrix, the switch set contained in the shortest path between each terminal user and the distribution transformer is backtracked. Considering that the terminal user is usually the end node of the network topology, the backtracking is performed from the end node where the terminal user is located to the root node where the distribution transformer is located, based on the node switch matrix. The backtracking principle is as follows: Let the terminal user node be node i, starting from the i-th column of the matrix, the non-zero element in that column is searched to be M. ki Then, starting from the k-th column of the matrix, search for the non-zero elements in that column until the root node is found. The set of matrix elements searched during the backtracking process of the terminal user is the shortest path for that terminal user. The shortest path usually includes two types of elements: line elements and switch elements. The set of switch elements is the switch set for that terminal user.

[0088] The process of obtaining the switch set of a component is as follows: Based on the node switch matrix, the set of switches contained in the shortest path between each operating component (such as a switch and a line) and the distribution transformer is traced back. The operating component is usually an element between two nodes in the network topology, so the node switch matrix is ​​required to trace back from the first node of the operating component to the root node where the distribution transformer is located, and the tracing principle remains unchanged; the set of matrix elements searched during the tracing process of the component is the shortest path of the operating component, and the set of switch elements contained in the shortest path is the switch set of the operating component.

[0089] Based on the node switch matrix and through backtracking, the switch sets of end users and components can be obtained. For example, the switch set of user LP4 in node 10 is LP4 = {S8, S3, S1}, the switch set of line 5 is L5 = {S4, S1}, and the switch set of switch S8 is S8 = {S3, S1}.

[0090] Preferably, the power supply reliability of each end user is analyzed based on the intersection of the switch set of each end user and the switch set of each component, including:

[0091] Step (1) Initialize h = s = 1;

[0092] Step (2) Initialize the iteration count r = 1 and set T h,r =0 and D h,r =0;

[0093] Step (3) Determine whether s is greater than N D If so, then output T. h,r and D h,r If not, proceed to steps (5) and (6); otherwise, proceed to step (4).

[0094] Step (4) Update T based on the switch failure rate of the switching device, according to the intersection of the switch set of the h-th terminal user and the switch set of the s-th element. h,r and D h,r Let s = s + 1, r = r + 1 and return to step (3);

[0095] Step (5) Determine whether h is greater than N. L If yes, then end the operation; otherwise, set h = h + 1, s = 1 and return to step (2).

[0096] Step (6) If T h,r Less than α and D h,r If the value is less than β, output "The power supply reliability of the h-th terminal user is high"; otherwise, output "The power supply reliability of the h-th terminal user is poor".

[0097] Among them, T h,r Let D be the average number of power outages per year for the h-th terminal user corresponding to the r-th iteration. h,r Let α be the average annual power outage time for the h-th terminal user corresponding to the r-th iteration, α be a preset threshold for the average annual power outage frequency for each terminal user, and β be a preset threshold for the average annual power outage time for each terminal user, where h∈[1,N]. L ],s,r∈[1,N D ], N L N represents the total number of end users in a low-voltage distribution network system. D This refers to the total number of components in a low-voltage distribution network system.

[0098] Among them, the average number of power outages per year and the average duration of power outages per year are used as indicators to analyze the power supply reliability of each end user.

[0099] Furthermore, step (4) includes:

[0100] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element is equal to the switch set of the s-th element, then update T according to the following formula. h,r and D h,r :

[0101]

[0102] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by one element, then update T according to the following formula. h,r and Dh,r :

[0103]

[0104] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by two elements, then update T according to the following formula. h,r and D h,r :

[0105]

[0106] Among them, T h,r-1 Let D be the average number of power outages per year for the h-th terminal user corresponding to the (r-1)-th iteration. h,r-1 Let λ be the average annual power outage time for the h-th terminal user corresponding to the (r-1)-th iteration. s Let μ be the failure rate of the s-th component. s Let p be the repair rate of the s-th element. 1,s p represents the probability of failure of the upstream protective switch adjacent to component s to operate after component s fails. 2,s The probability of failure of the upstream protection switch adjacent to the current input terminal of the transmission line after component s fails is given. The upstream protection switch is the protection switch located between the current input terminal of the transmission line and component s.

[0107] In an embodiment of the present invention, based on the switch sets of each terminal user and each component obtained in step 101, the pairwise membership relationship between each component and each user is determined according to set theory. The determination principle is as follows:

[0108] 1) When the intersection of the switch sets of each end user and each component is completely consistent with the switch set of the component, the set relationship is a direct impact relationship of the fault.

[0109] 2) When the intersection of the switch sets of each end user and each component differs from the switch set of each component by one switch element, it is a first-order failure-to-operate fault influence relationship.

[0110] 3) When the intersection of the switch sets of each end user and each component differs from the switch set of each component by two switch elements, it is a second-order failure-to-operate fault influence relationship.

[0111] Considering that most low-voltage power distribution systems have three-stage protection, and that the protection devices at the output terminals of the distribution transformers are consistent for any user and any component, the membership relationship between the two sets is at most a second-order failure-to-operate fault influence relationship.

[0112] In an embodiment of the present invention, a flowchart of the power supply reliability calculation method for power grid end users is shown below. Figure 3 As shown:

[0113] Step 1): Initialization: Establish a node switch matrix based on the network topology of the low-voltage distribution network, backtrack to find the switch sets of all end users, switches and lines, and set i = j = 1;

[0114] Step 2): Initialize the iteration count r = 1, and set the annual average number of power outages T as the reliability index of end user i. i,r =0 and average annual power outage time D i,r =0;

[0115] Step 3) Determine if j is greater than the total number of components N in the low-voltage distribution network. D If so, then output T. i,r and D i,r If not, proceed to steps 5) and 6); otherwise, proceed to step 4.

[0116] Step 4): Based on the membership relationship between the switch set of the i-th terminal user and the switch set of the j-th element, update the T of the i-th terminal user corresponding to the r-th iteration based on the switch failure rate. i,r and D i,r ;

[0117] If the fault directly affects the relationship, the update equation is:

[0118]

[0119] If the relationship is a first-order failure-to-operate fault, the update equation is:

[0120]

[0121] If the relationship is a second-order failure-to-operate fault, the update equation is:

[0122]

[0123] Then, let j = j + 1, r = r + 1 and return to step 3);

[0124] Step 5): Determine if i is greater than the total number N of end users in the low-voltage distribution network. L If yes, then end the operation; otherwise, set i = i + 1, j = 1 and return to step 2.

[0125] Step 6): If T i,r The number of power outages per year is less than the preset threshold α = 5 for the average number of power outages per year for end users. i,r If the power outage time is less than the preset threshold β = 0.5 for the average annual power outage time of the end user, then output "The power supply reliability of the i-th end user is high"; otherwise, output "The power supply reliability of the i-th end user is poor".

[0126] In the formula: i∈[1,N] L],j,r∈[1,N D ], λ j Let μ be the failure rate of component j. j p represents the repair rate of component j. 1,j p represents the probability of failure of the upstream protective switch adjacent to component j after a fault in component j. 2,j The probability of failure of the upstream protection switch adjacent to the current input terminal of the transmission line after a fault in component j is given. The upstream protection switch is the protection switch located between the current input terminal of the transmission line and component j.

[0127] This invention mainly provides a method for power supply reliability analysis of power grid end users. In this embodiment, the preset threshold values ​​of reliability indicators can be set according to actual engineering scenarios and are not limited to the preset threshold values ​​provided in this embodiment.

[0128] Before operating a low-voltage power distribution system, the power supply reliability of each end user can be quickly and accurately analyzed using the method described in the embodiments of the present invention. This enables a preliminary judgment on the rationality of the low-voltage power distribution system configuration. High reliability indicates that the network architecture and parameter configuration of the low-voltage power distribution system are reasonable; otherwise, the network architecture and parameters need to be readjusted. Therefore, the method described in the embodiments of the present invention provides a guarantee for the safe and stable operation of the power grid.

[0129] This invention provides a power supply reliability analysis device for power grid end users, such as... Figure 4 As shown, it includes:

[0130] The acquisition module is used to acquire the switch sets of each end user and the switch sets of each component based on the node switch matrix of the low-voltage distribution network system.

[0131] The analysis module is used to analyze the power supply reliability of each end user based on the intersection of the switch set of each end user and the switch set of each component;

[0132] Preferably, the node switch matrix M of the low-voltage distribution network system is determined by the following formula:

[0133]

[0134] In the formula, i and j are the node numbers of the nodes in the network topology of the low-voltage distribution network system, i,j∈[1,N], and N is the node number of the last node in the network topology of the low-voltage distribution network system.

[0135] When i≥j or i<j, j≠i+1, M ij =0;

[0136] When i < j, j = i + 1 and there is no switching device between the i-th node and the j-th node, M ij =1;

[0137] When i < j, j = i + 1 and there is a switching device between the i-th node and the j-th node, M ij Let be the name of the switching device between the i-th node and the j-th node.

[0138] Preferably, the acquisition module is specifically used for:

[0139] The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

[0140] The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer.

[0141] Among them, the components are switching equipment or lines in low-voltage distribution network systems.

[0142] Preferably, the analysis module includes:

[0143] An initialization unit is used to initialize h = s = 1;

[0144] The assignment unit is used to initialize the iteration count r = 1 and set T. h,r =0 and D h,r =0;

[0145] The first judgment unit is used to determine whether s is greater than N. D If so, then output T. h,r and D h,r If no, then execute the second judgment unit and the analysis unit; if not, then execute the calculation unit.

[0146] The calculation unit is used to update T based on the switch failure rate of the switching equipment, according to the intersection of the switch set of the h-th end user and the switch set of the s-th element. h,r and D h,r Let s = s + 1, r = r + 1 and return to the first judgment unit;

[0147] The second judgment unit is used to determine whether h is greater than N. L If yes, then end the operation; otherwise, set h = h + 1, s = 1 and return to the assignment unit.

[0148] Analysis unit, used if T h,r Less than α and D h,r If the value is less than β, output "The power supply reliability of the h-th terminal user is high"; otherwise, output "The power supply reliability of the h-th terminal user is poor".

[0149] Among them, T h,r Let D be the average number of power outages per year for the h-th terminal user corresponding to the r-th iteration. h,r Let α be the average annual power outage time for the h-th terminal user corresponding to the r-th iteration, α be a preset threshold for the average annual power outage frequency for each terminal user, and β be a preset threshold for the average annual power outage time for each terminal user, where h∈[1,N]. L ],s,r∈[1,N D ], N L N represents the total number of end users in a low-voltage distribution network system. D This refers to the total number of components in a low-voltage distribution network system.

[0150] Among them, the average number of power outages per year and the average duration of power outages per year are used as indicators to analyze the power supply reliability of each end user.

[0151] Furthermore, the computing unit is specifically used for:

[0152] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element is equal to the switch set of the s-th element, then update T according to the following formula. h,r and D h,r :

[0153]

[0154] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by one element, then update T according to the following formula. h,r and D h,r :

[0155]

[0156] If the intersection of the switch set of the h-th terminal user and the switch set of the s-th element differs from the switch set of the s-th element by two elements, then update T according to the following formula. h,r and D h,r :

[0157]

[0158] Among them, T h,r-1 Let D be the average number of power outages per year for the h-th terminal user corresponding to the (r-1)-th iteration. h,r-1 Let λ be the average annual power outage time for the h-th terminal user corresponding to the (r-1)-th iteration. s Let μ be the failure rate of the s-th component. s Let p be the repair rate of the s-th element. 1,s p represents the probability of failure of the upstream protective switch adjacent to component s to operate after component s fails. 2,sThe probability of failure of the upstream protection switch adjacent to the current input terminal of the transmission line after component s fails is given. The upstream protection switch is the protection switch located between the current input terminal of the transmission line and component s.

[0159] This invention comprehensively considers the characteristics of multi-level protection and switch failure in low-voltage distribution networks. With the aim of analyzing end-user reliability indicators, a node switch matrix is ​​established based on the network topology of the low-voltage distribution system. Based on this matrix, a backtracking method is used to search for the shortest paths between all end-users and various operating components and the distribution transformer, and switch sets are constructed. The membership relationship between each end-user and each component's switch sets is determined, and a method for calculating end-user power supply reliability indicators is proposed. This method is universally applicable to various low-voltage network structures.

[0160] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0161] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0162] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0163] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for power supply reliability analysis of an end user of an electrical network, characterized in that, The method includes: Based on the node switch matrix of a low-voltage distribution network system, the switch sets of each end user and each component are obtained, including: The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer. The component is a switchgear or line in a low-voltage power distribution network system; The power supply reliability of each end user is analyzed based on the intersection of the switch set of each end user and the switch set of each component. The analysis of the power supply reliability of each terminal user based on the intersection of the switch set of each terminal user and the switch set of each component includes: Step (1) Initialization ; Step (2) initialize the number of iterations and set and ; Step (3) judges whether it is greater than , if yes, outputs and , and executes Step (5) and Step (6), if not, executes Step (4); Step (4) updates the intersection of the switch set of the first end user and the switch set of the first element and the switch device refusal rate and , let and returns to step (3); Step (5) Judgment Is it greater than If yes, then end the operation; otherwise, let... And return to step (2); Step (6) If Less than at the same time Less than Then output "the first "High power supply reliability for the terminal user"; otherwise, output "The power supply reliability for the [number]th user is high". "Poor power supply reliability for individual end users"; in, For the first The iteration corresponding to the ... Average number of power outages per end user per year For the first The iteration corresponding to the ... Average annual power outage time per end user A threshold is preset for the average number of power outages per year for each end user. Set a threshold for the average annual power outage time for each end user. , , This refers to the total number of end users in a low-voltage distribution network system. This refers to the total number of components in a low-voltage distribution network system. Step (4) includes: If the first The set of switches for the terminal user and the first The intersection of the switch sets of the nth element is equal to the nth element. The set of switches for each element is updated as follows: and : ； If the first The set of switches for the terminal user and the first The intersection of the switch sets of each element and the first... If the switch set of each component differs by one element, then update it as follows: and : ； If the first The set of switches for the terminal user and the first The intersection of the switch sets of each element and the first... If the switch set of each element differs by two elements, then update it according to the following formula. and : ； in, For the first The iteration corresponding to the ... Average number of power outages per end user per year For the first The iteration corresponding to the ... Average annual power outage time per end user For the first Failure rate of individual components For the first Repair rate of each component For components After the fault and components The probability of failure to operate of adjacent upstream protective switches. For components The probability of failure to operate of the upstream protection switch adjacent to the current input terminal of the transmission line after a fault, wherein the upstream protection switch is located at the current input terminal of the transmission line and the component. s The protective switch between them.

2. The method as described in claim 1, characterized in that, The node switch matrix of a low-voltage distribution network system is determined by the following formula. : In the formula, , These are all node numbers in the network topology of a low-voltage distribution network system. , This refers to the node number of the last node in the network topology of a low-voltage distribution network system. when or hour, ; when And the first The node and the first When there are no switching devices between nodes ; when And the first The node and the first When there are switching devices between nodes For the first The node and the first The name of the switching equipment between nodes.

3. The method as described in claim 1, characterized in that, The node switch matrix based on the low-voltage distribution network system obtains the switch sets of each end user and the switch sets of each component, including: The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

4. A power supply reliability analysis device for power grid end users, characterized in that, The device includes: The acquisition module is used to acquire the switch sets of each end user and the switch sets of each component based on the node switch matrix of the low-voltage distribution network system. Specifically, it includes: The switch set for each end user is formed by using the switching equipment contained in the shortest path between each end user and the distribution transformer, and the switch set for each component is formed by using the switching equipment contained in the shortest path between each component and the distribution transformer. The component is a switchgear or line in a low-voltage power distribution network system; The analysis module is used to analyze the power supply reliability of each end user based on the intersection of the switch set of each end user and the switch set of each component; The analysis module includes: Initialization unit, used for initialization ; Assignment unit, used to initialize the number of iterations. and set and ; The first judgment unit is used to make judgments. Is it greater than If so, then output and Then execute the second judgment unit and the analysis unit; if not, execute the calculation unit. Calculation unit, used to calculate according to the first The set of switches for the terminal user and the first The intersection of the switch sets of each component is updated based on the failure rate of the switching device. and ,make And return to the first judgment unit; The second judgment unit is used to judge. Is it greater than If yes, then end the operation; otherwise, let... And return the assignment unit; Analysis unit, if Less than at the same time Less than Then output "the first "High power supply reliability for the terminal user"; otherwise, output "The power supply reliability for the [number]th user is high". "Poor power supply reliability for individual end users"; in, For the first The iteration corresponding to the ... Average number of power outages per end user per year For the first The iteration corresponding to the ... Average annual power outage time per end user A threshold is preset for the average number of power outages per year for each end user. Set a threshold for the average annual power outage time for each end user. , , This refers to the total number of end users in a low-voltage distribution network system. This refers to the total number of components in a low-voltage distribution network system. The computing unit is specifically used for: If the first The set of switches for the terminal user and the first The intersection of the switch sets of the nth element is equal to the nth element. The set of switches for each element is updated as follows: and : ； If the first The set of switches for the terminal user and the first The intersection of the switch sets of each element and the first... If the switch set of each component differs by one element, then update it as follows: and : ； If the first The set of switches for the terminal user and the first The intersection of the switch sets of each element and the first... If the switch set of each element differs by two elements, then update it according to the following formula. and : ； in, For the first The iteration corresponding to the ... Average number of power outages per end user per year For the first The iteration corresponding to the ... Average annual power outage time per end user For the first Failure rate of individual components For the first Repair rate of each component For components After the fault and components The probability of failure to operate of adjacent upstream protective switches. For components The probability of failure to operate of the upstream protection switch adjacent to the current input terminal of the transmission line after a fault, wherein the upstream protection switch is located at the current input terminal of the transmission line and the component. s The protective switch between them.

5. The apparatus as described in claim 4, characterized in that, The node switch matrix of a low-voltage distribution network system is determined by the following formula. : In the formula, , These are all node numbers in the network topology of a low-voltage distribution network system. , This refers to the node number of the last node in the network topology of a low-voltage distribution network system. when or hour, ; when And the first The node and the first When there are no switching devices between nodes ; when And the first The node and the first When there are switching devices between nodes For the first The node and the first The name of the switching equipment between nodes.

6. The apparatus as claimed in claim 4, characterized in that, The acquisition module is specifically used for: The node switching matrix of the low-voltage distribution network system is traced back using a node backtracking method to obtain the shortest path between each end user and the distribution transformer, as well as the shortest path between each component and the distribution transformer.

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