A reliability calculation method, system and storage medium for a multi-source distribution network

Abstract

The present invention discloses a reliability calculation method, system and storage medium for a multi-source distribution network. The method comprises the following steps: obtaining the first connection element and upstream and downstream relationships between each feeder area of ​​the multi-source distribution network, and the second connection element of the distributed power source accessing the feeder area; obtaining the fault area and its upstream feeder area under a preset fault scenario; dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area, and obtaining the islanding modes of the fault area and the downstream feeder area respectively; calculating the power outage time of the fault area, the upstream feeder area and the downstream feeder area according to the output data of the distributed power source and the islanding mode, and obtaining the reliability of the multi-source distribution network. By adopting the embodiment of the present invention, it is possible to consider multiple division methods of multi-source active islanding according to different fault scenarios and the output conditions of the distributed power source, so that the calculation result is more accurate and more in line with the current power supply conditions of the distributed power source.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network reliability measurement, and in particular to a reliability measurement method, system and storage medium for a multi-source distribution network. Background Art

[0002] In traditional distribution network reliability measurement systems, the chain reaction triggered by external grid failures is often the core component of the measurement. In traditional measurement processes, when an external grid failure occurs, a microgrid model is used to characterize the grid failure response, transitioning from grid-connected to islanded mode according to a fixed operating mode to ensure the continuity of basic power supply.

[0003] However, with the large-scale integration of distributed power sources, the distribution network structure has shifted from a single main power source to a multi-source coordinated power supply model, forming a multi-source island system with autonomous control capabilities. Traditional reliability measurement methods cannot accurately capture the deep coupling relationship between operation strategy and reliability, and are prone to falling into the trap of local optimal solutions. They ignore the global optimization space under multi-source coordination and cannot meet the reliability measurement needs of the new power system. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a reliability measurement method, system and storage medium for a multi-source distribution network, which can consider multiple multi-source active island division methods according to different fault scenarios and the output conditions of distributed power sources, so that the measurement results are more accurate and more in line with the current distributed power supply conditions.

[0005] An embodiment of the present invention provides a reliability calculation method for a multi-source distribution network, comprising:

[0006] Obtaining first connection elements and upstream and downstream relationships between feeder areas of a multi-source distribution network, and second connection elements of distributed power sources connected to feeder areas;

[0007] In a preset fault scenario, based on the first connection element and the upstream and downstream relationship, a fault area is screened from the feeder areas of the multi-source distribution network, and an upstream feeder area of ​​the fault area is obtained;

[0008] Dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area to obtain at least one set of islanding modes in the fault area and the downstream feeder area, respectively; the islanding modes include microgrid islanding and multi-source islanding;

[0009] According to the output data of the distributed power source and the island mode, the power outage time of the fault area, the upstream feeder area and the downstream feeder area under the fault scenario is calculated to obtain the reliability of the multi-source distribution network.

[0010] As an improvement to the above solution, in a preset fault scenario, according to the first connection element and the upstream and downstream relationship, a fault area is screened from the feeder area of ​​the multi-source distribution network, and an upstream feeder area of ​​the fault area is obtained, including:

[0011] In a preset line fault scenario, locating a feeder area where the line fault exists in the multi-source distribution network as a fault area, and obtaining an upstream feeder area of ​​the fault area according to the upstream and downstream relationship;

[0012] In a preset component failure scenario, the feeder area with line faults is located from the multi-source distribution network as the initial fault area;

[0013] The initial fault area is updated according to the first connection element and the upstream and downstream relationship to obtain a fault area, and an upstream feeder area of ​​the fault area is obtained according to the upstream and downstream relationship.

[0014] As an improvement to the above solution, updating the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtaining an upstream feeder area of ​​the fault area according to the upstream and downstream relationship, includes:

[0015] According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained;

[0016] If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area;

[0017] If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone;

[0018] According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

[0019] As an improvement to the above solution, the on-off states of the first connection element and the second connection element in the fault area and its downstream feeder area are dynamically adjusted to obtain at least one set of islanding modes in the fault area and the downstream feeder area, respectively, including:

[0020] If the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes in the fault area;

[0021] If the fault area includes less than two feeder areas, the islanding mode of the fault area is a microgrid islanding mode;

[0022] If the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of island modes in the downstream feeder area;

[0023] If the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

[0024] As an improvement to the above solution, if the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes in the fault area includes:

[0025] Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone;

[0026] In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

[0027] As an improvement to the above solution, if the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of island modes in the downstream feeder area includes:

[0028] Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition;

[0029] In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

[0030] As an improvement to the above solution, the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario is calculated based on the output data of the distributed power sources and the island mode to obtain the reliability of the multi-source distribution network, including:

[0031] Obtain output data of distributed power sources;

[0032] Obtaining, according to the type of the first connection element at the entrance of the fault area, a first power outage time of the upstream feeder area under the fault scenario;

[0033] Calculating a second power outage time of the fault area under the fault scenario according to the output data of the distributed power source connected in the island mode of the fault area;

[0034] Calculating a third power outage time of the downstream feeder area under the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area;

[0035] The reliability of the multi-source power distribution network is obtained according to the first power outage time, the second power outage time, and the third power outage time.

[0036] As an improvement to the above solution, the step of obtaining the output data of the distributed power source includes:

[0037] Obtain historical samples of predicted output deviations of distributed power sources;

[0038] Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample;

[0039] Establishing a fuzzy set of actual output of distributed power sources according to the mean and variance of the historical samples;

[0040] According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

[0041] As an improvement to the above solution, obtaining the first power outage time of the upstream feeder area in the fault scenario according to the type of the first connection element at the entrance of the fault area includes:

[0042] When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0;

[0043] When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

[0044] As an improvement to the above solution, the calculating, based on the output data of the distributed power sources connected in the island mode of the fault area, the second power outage time of the fault area in the fault scenario includes:

[0045] If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time;

[0046] Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area;

[0047] Calculating a first power supply time of the first distributed power supply according to the first power supply rate;

[0048] A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

[0049] As an improvement to the above solution, calculating the third power outage time of the downstream feeder area in the fault scenario according to the output data of the distributed power source connected in the island mode of the downstream feeder area includes:

[0050] If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time;

[0051] Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area;

[0052] calculating a second power supply time of the second distributed power supply according to the second power supply rate;

[0053] The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

[0054] An embodiment of the present invention further provides a reliability measurement system for a multi-source distribution network, comprising:

[0055] A physical connection relationship acquisition module is used to obtain the first connection elements and upstream and downstream relationships between the feeder areas of the multi-source distribution network, and the second connection elements of the distributed power supply access feeder area;

[0056] a fault and upstream zoning module, configured to, under a preset fault scenario, screen the feeder areas of the multi-source distribution network to obtain a fault area and obtain an upstream feeder area of ​​the fault area based on the first connection element and the upstream and downstream relationships;

[0057] a dynamic islanding division module, configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area, to obtain at least one set of islanding modes for the fault area and the downstream feeder area, respectively; the islanding modes include microgrid islanding and multi-source islanding;

[0058] The reliability calculation module is used to calculate the power outage time of the fault area, the upstream feeder area and the downstream feeder area under the fault scenario based on the output data of the distributed power supply and the island mode, so as to obtain the reliability of the multi-source distribution network.

[0059] As an improvement to the above solution, the fault and upstream partitioning module includes:

[0060] A first partitioning unit is configured to locate, in a preset line fault scenario, a feeder area where a line fault exists in the multi-source distribution network as a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship;

[0061] An initial fault area locating unit is used to locate a feeder area with a line fault in a multi-source distribution network as an initial fault area under a preset component failure scenario;

[0062] The second partitioning unit is configured to update the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship.

[0063] As an improvement to the above solution, the second partition division unit is specifically configured to:

[0064] According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained;

[0065] If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area;

[0066] If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone;

[0067] According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

[0068] As an improvement to the above solution, the dynamic island division module includes:

[0069] a first fault area island determination unit, configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes for the fault area if the fault area includes no less than two feeder areas;

[0070] a second fault area islanding determination unit, configured to determine that the islanding mode of the fault area is a microgrid islanding mode if the fault area includes less than two feeder areas;

[0071] a first downstream island determining unit, configured to dynamically adjust the on / off states of the first connecting element and the second connecting element in the downstream feeder area if the downstream feeder area of ​​the fault area includes no less than two feeder areas, to obtain at least one set of island modes for the downstream feeder area;

[0072] The second downstream island determining unit is configured to determine that, if the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

[0073] As an improvement to the above solution, the first fault area island determination unit is specifically configured to:

[0074] Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone;

[0075] In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

[0076] As an improvement to the above solution, the first downstream island determining unit is specifically configured to:

[0077] Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition;

[0078] In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

[0079] As an improvement to the above solution, the reliability calculation module includes:

[0080] An output data acquisition unit, used to acquire output data of a distributed power source;

[0081] a first power outage time calculation unit, configured to obtain a first power outage time of the upstream feeder area under the fault scenario according to a type of the first connection element at the entrance of the fault area;

[0082] A second power outage time calculation unit is configured to calculate a second power outage time of the fault area under the fault scenario based on the output data of the distributed power source connected in the island mode of the fault area;

[0083] A third power outage time calculation unit is configured to calculate a third power outage time of the downstream feeder area under the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area;

[0084] The reliability calculation unit is used to obtain the reliability of the multi-source distribution network according to the first power outage time, the second power outage time and the third power outage time.

[0085] As an improvement to the above solution, the output data acquisition unit is specifically configured to:

[0086] Obtain historical samples of predicted output deviations of distributed power sources;

[0087] Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample;

[0088] According to the mean and variance of the historical samples, a fuzzy set of actual output of distributed power generation is established;

[0089] According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

[0090] As an improvement to the above solution, the first power outage time calculation unit is specifically configured to:

[0091] When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0;

[0092] When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

[0093] As an improvement to the above solution, the second power outage time calculation unit is specifically configured to:

[0094] If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time;

[0095] Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area;

[0096] Calculating a first power supply time of the first distributed power supply according to the first power supply rate;

[0097] A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

[0098] As an improvement to the above solution, the third power outage time calculation unit is specifically configured to:

[0099] If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time;

[0100] Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area;

[0101] calculating a second power supply time of the second distributed power supply according to the second power supply rate;

[0102] The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

[0103] An embodiment of the present invention also discloses a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute a reliability calculation method for a multi-source distribution network as described in any one of the above.

[0104] Compared with the prior art, the present invention discloses a reliability measurement method, system and storage medium for a multi-source distribution network, which obtains the first connection element and upstream and downstream relationship between each feeder area of ​​the multi-source distribution network, and the second connection element of the distributed power supply access feeder area; in a preset fault scenario, according to the first connection element and the upstream and downstream relationship, the fault area is screened from the feeder area of ​​the multi-source distribution network, and the upstream feeder area of ​​the fault area is obtained; the on-off state of the first connection element and the second connection element in the fault area and its downstream feeder area is dynamically adjusted to obtain at least one set of island modes for the fault area and the downstream feeder area respectively; the island mode includes microgrid island and multi-source island; according to the output data of the distributed power supply and the island mode, the power outage time of the fault area, the upstream feeder area and the downstream feeder area under the fault scenario is calculated to obtain the reliability of the multi-source distribution network. By adopting the embodiment of the present invention, it is possible to consider multiple division methods of multi-source active island according to different fault scenarios and the output conditions of distributed power supplies, so that the measurement result is more accurate and more in line with the current distributed power supply situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Figure 1 This is a schematic flow chart of the steps of a reliability calculation method for a multi-source distribution network provided by an embodiment of the present invention;

[0106] Figure 2 This is a schematic diagram of the result of the first multi-source island division provided by an embodiment of the present invention;

[0107] Figure 3 This is a schematic diagram of the result of the second multi-source island division provided by an embodiment of the present invention;

[0108] Figure 4It is a structural diagram of a reliability measurement system for a multi-source distribution network provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0109] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0110] In the description of the specification and claims, it should be understood that the terms "first," "second," etc., are used solely for descriptive purposes to distinguish between identical technical features and are not to be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to, nor do they necessarily describe a sequential or chronological order. The terms are interchangeable where appropriate. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one of those features.

[0111] In the prior art, the reliability of power distribution systems is mainly calculated through simulation or analytical methods.

[0112] Simulation methods typically use Monte Carlo simulation to simulate the process of components or equipment in the power distribution system failing, undergoing maintenance, or shutting down. However, simulation methods are difficult to obtain accurate indicator calculation results.

[0113] The traditional analytical method decouples the topological search algorithm of reliability assessment from the optimization operation model through the idea of ​​heuristic optimization, which makes it difficult to integrate the coupling relationship between the optimization operation strategy and reliability evaluation indicators under multi-source access.

[0114] Based on the above considerations, an embodiment of the present invention provides a reliability calculation method for a multi-source distribution network. Figure 1 In this embodiment, the reliability calculation method of the multi-source distribution network is specifically performed through steps S1 to S4:

[0115] S1. Acquire first connection elements and upstream and downstream relationships between feeder areas of a multi-source distribution network, and second connection elements of distributed power sources connected to feeder areas.

[0116] In the embodiments of the present invention, the connecting elements in the multi-element distribution network are circuit breakers or sectionalizers. Circuit breakers can quickly trip when a fault occurs, without disrupting upstream power outages. Some sectionalizers must actively operate when a fault occurs to isolate the faulty section and ensure normal power supply to the non-faulty sections.

[0117] It should be noted that the connection elements in the embodiments of the present invention are merely examples, intended to illustrate two types of connection elements: those that automatically disconnect and those that do not, respectively. These differ in their impact on the circuit. In some embodiments, the connection element may include a fuse, which functions similarly to a circuit breaker, quickly disconnecting the faulty section when a fault occurs. In some embodiments, the connection element may also include an automated sectioning switch, which automatically disconnects. The specific selection of the first and second connection elements does not affect the beneficial effects of the embodiments of the present invention.

[0118] S2. In a preset fault scenario, based on the first connection element and the upstream and downstream relationship, a fault area is screened from the feeder areas of the multi-source distribution network, and an upstream feeder area of ​​the fault area is obtained.

[0119] It should be noted that the preset fault scenarios include line faults or component faults that may exist in each feeder zone. In this embodiment of the present invention, fault scenarios are divided into two categories: line fault scenarios and component fault scenarios. Line fault scenarios directly affect the feeder zone where the fault occurs, while component fault scenarios may also affect feeder zones adjacent to the feeder zone where the fault occurs.

[0120] S3. Dynamically adjust the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area to obtain at least one set of island modes in the fault area and the downstream feeder area respectively; the island modes include microgrid islands and multi-source islands.

[0121] In the prior art, when an external power grid fails, a microgrid switches from grid-connected to islanded mode according to a fixed operating mode. However, with the large-scale access of distributed power sources, multi-source active islanding has the ability to restore local power grids. Furthermore, when the fault location and time period vary, multi-source active islanding can be divided in a variety of ways. In an embodiment of the present invention, the on / off states of the first connection element and the second connection element are dynamically adjusted to determine the corresponding power outage time under different islanding division methods. This makes the reliability calculation results of the multi-source distribution network more accurate and more consistent with the current power supply conditions of distributed power sources.

[0122] S4. Calculate the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario based on the output data of the distributed power sources and the island mode, and obtain the reliability of the multi-source distribution network.

[0123] By adopting the embodiments of the present invention, the power outage time under different fault scenarios and different multi-source islanding scenarios can be analyzed, and the reliability of the multi-source distribution network can be calculated based on the probability of occurrence of each scenario.

[0124] In the above scheme, various multi-source active island division methods can be considered according to different fault scenarios and the output conditions of distributed power sources, so that the measurement results are more accurate and more in line with the current distributed power supply conditions.

[0125] In some preferred embodiments, step S1 is specifically performed by establishing an active distribution network topology information matrix, which can reflect the first connection elements and upstream and downstream relationships between each feeder area of ​​the multi-source distribution network, and the association relationship between the second connection elements of the distributed power supply access feeder area, which is helpful for subsequent calculations.

[0126] Preferably, step S1, obtaining the first connection elements and upstream and downstream relationships between feeder areas of the multi-source distribution network, and the second connection elements of the distributed power sources connected to the feeder areas, includes:

[0127] Obtaining a first connection element between each feeder area of ​​the multi-source distribution network and establishing an entry element switch type vector;

[0128] Obtaining a second connection element of a distributed power supply access feeder area and the feeder area to which it is connected, and establishing a distributed power supply access vector;

[0129] The upstream and downstream relationships between feeder areas in a multi-source distribution network are obtained, and a feeder area downstream adjacent matrix is ​​established.

[0130] For example, the entry element switch type vector is , Expressed as:

[0131] (1);

[0132] in, Indicates that the first connecting element at the entrance of feeder zone k is a section switch; Indicates that the first connection element at the entrance of feeder zone k is a circuit breaker; is the total number of feeder zones.

[0133] Distributed power sources are connected to the feeder area of ​​the multi-source distribution network through branch lines. In some feeder areas, distributed power sources may not be connected. The distributed power source access vector includes the access position vector and the branch line access method vector. The access position vector is , Expressed as:

[0134] (2);

[0135] in, Indicates that the branch line f in feeder area k is connected to the distributed power supply. Indicates that the branch line f in the feeder area f is not connected to the distributed power source; is the total number of branch lines in feeder area k. The access position vector is It is a prerequisite for whether the feeder area can be used as an island.

[0136] The branch line access vector is , Expressed as:

[0137] (3);

[0138] in, It indicates that the branch line f in the feeder area k is connected to the main line through the section switch; It indicates that the branch line f in the feeder area k is connected to the main line through a circuit breaker.

[0139] The downstream adjacent matrix of the feeder area is , Expressed as:

[0140] (4);

[0141] in, The downstream adjacent feeder zone of feeder zone i is j, Indicates that the downstream of feeder zone i is not adjacent to feeder zone j.

[0142] by Figure 2 Conduct analysis, Figure 2 There are 11 feeder zones in total, N = 11. Entry element switch type vector , the access position vector is , the branch line access vector is , the adjacent matrix of the downstream feeder area is .

[0143] As a preferred embodiment, step S2, in a preset fault scenario, based on the first connection element and the upstream and downstream relationship, screen the fault area from the feeder area of ​​the multi-source distribution network, and obtain the upstream feeder area of ​​the fault area, and perform steps S21-S23:

[0144] S21. In a preset line fault scenario, locate a feeder area where the line fault exists in the multi-source distribution network as a fault area, and obtain an upstream feeder area of ​​the fault area based on the upstream and downstream relationship.

[0145] S22. In a preset component failure scenario, locate a feeder area with a line fault in the multi-source distribution network as an initial fault area.

[0146] S23. Update the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship.

[0147] In some preferred embodiments, step S21 is performed by Indicates the line fault condition in the feeder area, namely:

[0148] (5);

[0149] in, Indicates that a line fault occurs in feeder area q. Indicates that the line in feeder area q is working normally.

[0150] It should be noted that, for the sake of clarity and conciseness, the specific embodiments of the present invention consider line failure scenarios in first-order feeder areas. However, in actual applications, scenarios in which line failures occur simultaneously in second-order and higher-order feeder areas may also occur. The reliability measurement method for a multi-source distribution network described in the embodiments of the present invention can also be used, with the computational complexity being adaptively increased.

[0151] In some preferred embodiments, step S22 is performed by Indicates the component fault condition in the feeder area, namely:

[0152] (6);

[0153] in, Indicates that a component failure occurs in feeder zone q. It indicates that the components in feeder zone q are working properly.

[0154] It should be noted that in the embodiments of the present invention, the component failure scenario is mainly the failure of the first connection component, that is, the failure of the feeder zone entrance component. This is because the failure of the feeder zone entrance component will directly affect the operation status of the upstream and downstream adjacent feeder zones.

[0155] When a permanent fault occurs on a line within a feeder area, the entire feeder area becomes a fault zone. The duration of the multi-source distribution network outage is related to the first connection element at the entrance to the fault zone and its adjacent feeder areas. Furthermore, when a permanent fault occurs on the first connection element within a feeder area, its upstream and downstream feeder areas are directly affected, and the fault zone is expanded compared to a line fault scenario.

[0156] The fault scenario is a line fault scenario occurring in feeder area A. If the first connecting element at the entrance of feeder area A is a circuit breaker, the circuit breaker can be instantly disconnected after the fault, and the state of its upstream feeder area is not affected. At this time, feeder area A is the initial fault area, the upstream feeder area is the working area, and the power outage time of the upstream feeder area is zero; if the first connecting element at the entrance of feeder area A is a section switch, the nearest upstream circuit breaker connected to the feeder area is instantly disconnected, that is, the fault area will be extended to the nearest upstream feeder area with the circuit breaker as the first connecting element. After the disconnector in feeder area A is changed from closed to open, the feeder area upstream of feeder area A in the fault area can resume main power supply. At this time, the power outage time is the isolation time.

[0157] In the fault scenario described above, when a component failure occurs in feeder area A, neither the circuit breaker nor the section switch can achieve isolation and tripping after the fault. Therefore, the adjacent upstream feeder areas will be affected, and the fault area will be expanded to the adjacent feeder areas. That is to say, in the component failure scenario, feeder area A and its upstream adjacent feeder areas are used as the initial fault areas. After the initial fault area is determined, the other steps are the same as those in the line fault scenario.

[0158] Further, preferably, step S23, updating the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtaining an upstream feeder area of ​​the fault area according to the upstream and downstream relationship, includes:

[0159] According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained;

[0160] If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area;

[0161] If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone;

[0162] According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

[0163] It is understood that if the first connecting element at the entrance to the initial fault zone is a circuit breaker, the circuit breaker can be disconnected instantly after the fault occurs. The initial fault zone becomes the fault zone, and the upstream of the fault zone becomes the working zone, with a power outage duration of zero. The power outage duration of the upstream feeder zone is the fault repair time. If the first connecting element at the entrance to the initial fault zone is a sectionalizer, it must wait until the upper-level circuit breaker trips before it can trip and isolate the system. After that, power is restored by the main power source. At this point, the initial fault zone is further extended to the nearest upstream feeder zone with the circuit breaker as the first connecting element, becoming the fault zone.

[0164] It should be noted that, in one embodiment of the present invention, when the fault scenario is a line fault scenario occurring in feeder area A, and the first connecting element at the entrance of feeder area A is a section switch, the initial fault area is directly expanded to the nearest upstream feeder area with a circuit breaker as the first connecting element during the determination of the initial fault area; and in another embodiment of the present invention, for example, when the fault scenario is an element fault scenario occurring in feeder area A, the initial fault area is only feeder area A and its upstream adjacent feeder area, and the initial fault area is subsequently expanded. The execution of these two methods does not conflict, and in the first embodiment, feeder area A and its upstream adjacent feeder area can also be first used as the initial fault area, and then the initial fault area is expanded in step S23. The specific detailed process of determining the initial fault area and the fault area does not affect the beneficial effects produced by the present invention.

[0165] As a preferred embodiment, step S3, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area to obtain at least one set of islanding modes in the fault area and the downstream feeder area, is performed through steps S31-S34:

[0166] S31. If the fault area includes at least two feeder areas, dynamically adjust the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of islanding modes in the fault area;

[0167] S32. If the fault area includes less than two feeder areas, the islanding mode of the fault area is a microgrid islanding mode;

[0168] S33. If the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjust the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of islanding modes in the downstream feeder area;

[0169] S34. If the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

[0170] In this embodiment of the present invention, if the fault zone includes multiple feeder zones, partial power restoration can be achieved within the fault zone. Similarly, if the downstream feeder zone includes multiple feeder zones, partial or full power restoration can also be achieved within the fault zone. Therefore, the islanding of the fault zone and the downstream feeder zones has been further adjusted to fully accommodate the power supply conditions of distributed generation in the actual operation of a multi-source distribution network.

[0171] Furthermore, preferably, in step S31, if the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of islanding modes in the fault area includes:

[0172] Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone;

[0173] In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

[0174] Preferably, step S33, if the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of island modes in the downstream feeder area, includes:

[0175] Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition;

[0176] In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

[0177] See Figure 2 In a preferred embodiment, a result of multi-source island division is given. Figure 2 In the figure, when a line fault occurs in feeder area S5, circuit breakers B3-6, B8-9, and B11-12 instantly trip to isolate the fault. Then, switch D2-3 and circuit breaker B8 cut off the fault line from the system. According to the microgrid islanding results, feeder areas S7-S11 downstream of feeder area S5 are all in microgrid islanding operation mode. For feeder area S6, since there is no distributed power supply access locally, it is also a fault area before isolation and power transfer.

[0178] In an embodiment of the present invention, by adjusting the on-off state of the first connecting element and the second connecting element in the fault area, specifically, by closing the circuit breakers and disconnectors in the feeder areas S7-S9, the power supply to the feeder area S6 is restored. At this time, the power outage time is changed from the fault transfer time to the fault isolation time, the island mode of the feeder areas S6-S9 is a multi-source island, and the island mode of the feeder areas S10 and S11 is a microgrid island.

[0179] Since the access capacity and load capacity of distributed power sources in each feeder area are different, and the source and load fluctuations and uncertainties during the fault period, multiple division combinations may appear in the multi-distribution network island.

[0180] See Figure 3 In another preferred embodiment, the power supply to feeder area S6 is restored by closing the circuit breakers and disconnectors of feeder area S7-S11. At this time, the power outage time is changed from fault transfer time to fault isolation time, and the island mode of feeder area S6-S11 is multi-source island.

[0181] exist Figure 2 and Figure 3 Under the multi-source distribution network architecture and fault scenario shown in the figure, two groups of island modes are obtained in the fault area. Figure 2 The middle feeder area S5 is the fault area and is in the microgrid island mode. Since the first connecting element at the entrance of the fault area is a section switch, the power outage time of its upstream feeder area is the fault isolation time; feeder areas S6-S9 are in the multi-source island mode, and the power outage time is determined by the distributed power supply in the multi-source island; feeder areas S10 and S11 are in the microgrid island mode, and the power outage time is determined by the distributed power supply in the microgrid island. Figure 3 The middle feeder area S5 is the fault area and is in the microgrid island mode. Since the first connecting element at the entrance of the fault area is a section switch, the power outage time of its upstream feeder area is the fault isolation time; feeder areas S6-S11 are in the multi-source island mode, and the power outage time is determined by the distributed power supply in the multi-source island.

[0182] As a preferred embodiment, step S4, based on the output data of the distributed power source and the island mode, calculate the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario to obtain the reliability of the multi-source distribution network, and perform steps S41-S45:

[0183] S41, obtaining output data of distributed power sources;

[0184] S42. Obtaining a first power outage time of the upstream feeder area in the fault scenario according to a type of the first connection element at the entrance of the fault area;

[0185] S43. Calculate a second power outage time of the fault area in the fault scenario based on the output data of the distributed power source connected in the island mode of the fault area;

[0186] S44. Calculate a third power outage time of the downstream feeder area in the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area;

[0187] S45. Obtain reliability of the multi-source distribution network according to the first power outage time, the second power outage time, and the third power outage time.

[0188] Compared to the forward instantaneous island area, backward instantaneous island area, and backward delayed island area visible in the microgrid island, the support of multi-source island division for fault recovery is mainly reflected in the downstream of the fault. This is because the power outage time of the upstream feeder area is the isolation time, and the main power supply can be restored after the fault is isolated; and for the backward instantaneous and backward delayed, that is, the downstream feeder area, the downstream power supply recovery can be restored by dividing the multi-source island, and the feeder area without distributed power supply is restored, and the power outage time is converted from the fault repair time to the fault isolation time. In an embodiment of the present invention, by respectively calculating the first power outage time, the second power outage time, and the third power outage time, the impact on the multi-source distribution network can be reflected. More importantly, the distributed power supply can be further fully utilized.

[0189] Furthermore, preferably, step S41, obtaining output data of the distributed power source, includes:

[0190] Obtain historical samples of predicted output deviations of distributed power sources;

[0191] Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample;

[0192] Establishing a fuzzy set of actual output of distributed power sources according to the mean and variance of the historical samples;

[0193] According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

[0194] It should be noted that due to the uncertainty of photovoltaic output, there is a deviation between actual output and predicted output. In this embodiment of the present invention, the predicted deviation is measured by using historical samples of the predicted output deviation of the distributed power source to generate an actual photovoltaic output sequence. This allows the embodiment of the present invention to fully and accurately consider the photovoltaic fluctuation characteristics in different time periods when performing multi-source islanding.

[0195] In a preferred embodiment, the first-order moment estimation and the second-order moment estimation of the historical samples are expressed as:

[0196] (7);

[0197] in, is the historical sample of the predicted output deviation of the distributed power generation, is the first-order moment estimate, is the second-order moment estimate, is the mean of the historical samples, is the variance of the historical sample, is the number of samples, is the lth sample.

[0198] Due to the average deviation of the predicted output and variance There is uncertainty, and a fuzzy set of photovoltaic actual output characteristics based on moment information distribution is established:

[0199] (8);

[0200] (9);

[0201] in, is the fuzzy set of actual photovoltaic output, is the average sequence of actual photovoltaic output and variance series An uncertain set of is a random variable The distribution set of To find the probability function, represent the random variable The distribution belongs to The probability of is 1; To find the expected function; and are the upper and lower limits of the mean, respectively; and are the upper and lower limits of the variance respectively; and It is the allowable deviation coefficient, which is used to control the conservatism of the fuzzy set.

[0202] Then, a sample is drawn from the fuzzy set and multiplied by the installed capacity of the distributed generation at each node to obtain the actual distributed photovoltaic output at each node at each moment. In this embodiment of the present invention, Latin hypercube sampling (LHS) is employed. LHS is a stratified sampling method that divides the probability distribution model into N intervals and samples the variables in each subinterval separately, thereby ensuring that the sampling points cover the entire distribution space. This ensures that each horizontal partition in the parameter space has only one sample, avoiding redundancy and maintaining statistical properties such as uniformity and unbiasedness. Latin hypercube sampling is used to sample the fitted distributed photovoltaic moment estimates, thereby forming a photovoltaic actual output sequence and generating several sets of output scenarios and scenario probabilities.

[0203] By adopting the above-mentioned modeling method and the output data of distributed power sources, by modeling the association between the output fluctuation of distributed power sources and the changes in load demand, it is possible to achieve refined modeling of power shortage under multi-source load sequence fluctuations.

[0204] Preferably, step S42, obtaining the first power outage time of the upstream feeder area in the fault scenario according to the type of the first connection element at the entrance of the fault area, includes:

[0205] When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0;

[0206] When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

[0207] In a specific embodiment, the fault scenario is a line fault scenario. When the first connecting element at the entrance of the feeder area is a circuit breaker, the status of the upstream feeder area is not affected, and the circuit breaker can be disconnected instantly after the fault. The upstream feeder area is a working area and the power outage time is zero; when the first connecting element at the entrance of the feeder area is a section switch, the nearest upstream circuit breaker connected to the feeder area is instantly disconnected, forming a fault area, which includes the main fault section and the affected fault section. After the isolation switch at the entrance of the main fault section is turned from closed to open, the main power supply can be restored to the affected fault section. The power outage time of the affected fault section is the isolation time, which is expressed as the power outage time of the fault area in the embodiment of the present invention.

[0208] In some preferred embodiments, step S43, calculating the second power outage time of the fault area in the fault scenario according to the output data of the distributed power supply connected in the island mode of the fault area, includes:

[0209] If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time;

[0210] Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area;

[0211] Calculating a first power supply time of the first distributed power supply according to the first power supply rate;

[0212] A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

[0213] It should be noted that within the fault zone, if no distributed power generation is connected to the branch line, the second power outage time is the fault repair time. If a distributed power generation is connected to the branch line and the head-end switch is a circuit breaker, the fault zone instantly enters microgrid island mode, and the second power outage time is determined based on the increased supply of the distributed power generation and the fault repair time. In this embodiment of the present invention, the first power supply time represents the increased supply of the distributed power generation.

[0214] For example, if a distributed power source is connected to the branch line and the head-end switch is a circuit breaker, and the distributed power source can fully augment the fault area, the second power outage time is 0. If there is no distributed power source, the second power outage time is the fault repair time. If a distributed power source is connected to the branch line and the head-end switch is a section switch, and the distributed power source can fully augment the fault area, the second power outage time is the isolation time.

[0215] Preferably, step S44, calculating the third power outage time of the downstream feeder area in the fault scenario according to the output data of the distributed power source connected in the island mode of the downstream feeder area, includes:

[0216] If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time;

[0217] Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area;

[0218] calculating a second power supply time of the second distributed power supply according to the second power supply rate;

[0219] The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

[0220] It should be noted that, in an embodiment of the present invention, when the entry element of the adjacent feeder area downstream of the fault area is a circuit breaker, the downstream circuit breaker will trip instantly. By optimizing the switch state of the downstream feeder area, if there are multiple switches closed, the multi-source island area will be entered to achieve recovery of the downstream load area; if the switch is disconnected, the state of the island microgrid will remain unchanged. If the entry element of the adjacent feeder area downstream of the fault area is a segmented switch, it is necessary to wait for the upstream circuit breaker to trip instantly before the downstream segmented switch can trip. By optimizing the switch state of the downstream feeder area, if there are multiple switches closed, the multi-source island area will be entered to achieve recovery of the downstream load area; if the switch is disconnected, the state of the island microgrid will remain unchanged. The third power outage time is determined by the distributed power supply increase and fault transfer time in the downstream feeder area.

[0221] Exemplarily, if the entry element of the adjacent feeder area downstream of the fault area is a circuit breaker, and the distributed power source can fully increase the supply to the downstream feeder area, the third power outage time is 0; if the entry element of the adjacent feeder area downstream of the fault area is a circuit breaker, but there is no distributed power source, the third power outage time is the fault transfer time; if the entry element of the adjacent feeder area downstream of the fault area is a section switch, and the distributed power source can fully increase the supply to the downstream feeder area, the third power outage time is the isolation time.

[0222] When calculating the first power supply rate and the second power supply rate, both are based on the different operation methods of microgrid islands and multi-islands. In a preferred embodiment of the present invention, a specific calculation method for calculating the power supply rate is provided.

[0223] For the isolated microgrid island, the output and load curves of distributed power sources during the fault period have time-series variation characteristics. Therefore, it is necessary to calculate the distributed power supply rate under different output scenarios and different fault periods. The range of the distributed power supply rate is between [0,1]. When the output of the distributed power source during the t period is higher than the sum of the loads on the branch line, it means that all the loads can be supplied by the distributed power source at this time, and the distributed power supply rate is 1; when the output of the distributed power source during the t period is lower than the sum of the loads on the branch line, it means that only part of the load can be supplied by the distributed power source at this time, and the remaining part will be reduced. The distributed power supply rate is When the DG has no output during period t, it means that all loads are reduced and the DG power supply rate is 0. The power supply rate of the microgrid island is expressed as:

[0224] (10);

[0225] in, is the output of the f-th branch line in feeder area q at time t under scenario s, is the load of the fth branch line in feeder area q at the tth moment.

[0226] For multi-source islands, since the islands are all located in adjacent feeder areas and the distance between feeder areas is relatively close, line losses can be ignored and the distributed power supply rate is calculated in the form of source-load balance. In this case, the distributed power supply and load on different branch lines within the island range need to be summed and calculated. The distributed power supply rate range is between [0, 1]. The power supply rate of multi-source islands is expressed as:

[0227] (11);

[0228] Among them, is the output of feeder zone j in the multi-source island zone at time t under scenario s, is the load of feeder zone j in the multi-source island zone at time t.

[0229] In a preferred embodiment of the present invention, the opening and closing states of the inlet components of each feeder zone downstream of the faulty feeder zone are represented by decision variables, which are represented as follows:

[0230] (12);

[0231] in, is a 0-1 variable, j=(q+1,q+2,…,N); Indicates that a fault occurs in feeder zone q, and the first connecting element at the entrance of the jth feeder zone downstream is closed at time t and disconnected at time .

[0232] In a line fault scenario, the total power outage time obtained by combining the first power outage time, the second power outage time, and the third power outage time is expressed as:

[0233]

[0234] in, is feeder zone j and all downstream feeder zones; is the power supply rate of the distributed generation in the isolated microgrid area of ​​the f-th branch line in the feeder area j in the t-th period under scenario s; is the power supply rate of the distributed generation in the multi-source island area where the feeder area j is located in the tth period of scenario s; is the fault isolation time; t r Fault repair time; Fault transfer time.

[0235] In a component failure scenario, the total power outage time obtained by combining the first power outage time, the second power outage time, and the third power outage time is expressed as:

[0236]

[0237] Furthermore, preferably, the objective function of reliability is expressed as:

[0238] (15);

[0239] Among them, T is the total statistical period, is the total number of distributed power generation scenarios, is the probability of scene s appearing, is the line failure rate of feeder zone q, is the power outage time after the line fault in feeder area q under scenario s, is the switch failure rate in feeder zone q, is the power outage time after the switch failure in feeder zone q under scenario s.

[0240] By solving the above objective function, the reliability of the multi-source distribution network can be obtained. In some preferred embodiments, when solving the objective function, in order to avoid frequent switching on and off during the recovery process, the total number of switch operations and the number of operations in each fault section are constrained. The constraints are expressed as:

[0241] (16);

[0242] (17);

[0243] in, is the upper limit of the number of switch operations, and in each t period, the action switch can only operate once at most.

[0244] The reliability calculation method of a multi-source distribution network provided by an embodiment of the present invention can consider multiple multi-source active island division methods according to different fault scenarios and the output conditions of distributed power sources, so that the measurement results are more accurate and more in line with the current distributed power supply conditions.

[0245] The embodiment of the present invention provides a reliability measurement system for a multi-source distribution network. Figure 4 The reliability calculation system of the multi-source distribution network includes a physical connection relationship acquisition module 11, a fault and upstream partitioning module 12, a dynamic islanding division module 13 and a reliability calculation module 14, wherein:

[0246] A physical connection relationship acquisition module 11 is used to acquire the first connection elements and upstream and downstream relationships between the feeder areas of the multi-source distribution network, and the second connection elements of the distributed power supply access feeder area;

[0247] a fault and upstream zoning module 12 for screening a fault area from feeder areas of a multi-source distribution network and obtaining an upstream feeder area of ​​the fault area based on the first connection element and the upstream and downstream relationship under a preset fault scenario;

[0248] A dynamic islanding division module 13 is configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area, respectively obtaining at least one set of islanding modes for the fault area and the downstream feeder area; the islanding modes include microgrid islanding and multi-source islanding;

[0249] The reliability calculation module 14 is used to calculate the power outage time of the fault area, the upstream feeder area and the downstream feeder area under the fault scenario based on the output data of the distributed power supply and the island mode, so as to obtain the reliability of the multi-source distribution network.

[0250] As a preferred implementation, the fault and upstream partitioning module 12 includes:

[0251] A first partitioning unit is configured to locate, in a preset line fault scenario, a feeder area where a line fault exists in the multi-source distribution network as a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship;

[0252] An initial fault area locating unit is used to locate a feeder area with a line fault in a multi-source distribution network as an initial fault area under a preset component failure scenario;

[0253] The second partitioning unit is configured to update the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship.

[0254] Furthermore, preferably, the second partition division unit is specifically configured to:

[0255] According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained;

[0256] If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area;

[0257] If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone;

[0258] According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

[0259] As a preferred implementation, the dynamic island division module 13 includes:

[0260] a first fault area island determination unit, configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes for the fault area if the fault area includes no less than two feeder areas;

[0261] a second fault area islanding determination unit, configured to determine that the islanding mode of the fault area is a microgrid islanding mode if the fault area includes less than two feeder areas;

[0262] a first downstream island determining unit, configured to dynamically adjust the on / off states of the first connecting element and the second connecting element in the downstream feeder area if the downstream feeder area of ​​the fault area includes no less than two feeder areas, to obtain at least one set of island modes for the downstream feeder area;

[0263] The second downstream island determining unit is configured to determine that, if the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

[0264] Furthermore, preferably, the first fault area island determining unit is specifically configured to:

[0265] Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone;

[0266] In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

[0267] Preferably, the first downstream island determining unit is specifically configured to:

[0268] Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition;

[0269] In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

[0270] As a preferred embodiment, the reliability calculation module 14 includes:

[0271] An output data acquisition unit, used to acquire output data of a distributed power source;

[0272] a first power outage time calculation unit, configured to obtain a first power outage time of the upstream feeder area under the fault scenario according to a type of the first connection element at the entrance of the fault area;

[0273] A second power outage time calculation unit is configured to calculate a second power outage time of the fault area under the fault scenario based on the output data of the distributed power source connected in the island mode of the fault area;

[0274] A third power outage time calculation unit is configured to calculate a third power outage time of the downstream feeder area under the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area;

[0275] The reliability calculation unit is used to obtain the reliability of the multi-source distribution network according to the first power outage time, the second power outage time and the third power outage time.

[0276] Furthermore, preferably, the output data acquisition unit is specifically configured to:

[0277] Obtain historical samples of predicted output deviations of distributed power sources;

[0278] Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample;

[0279] According to the mean and variance of the historical samples, a fuzzy set of actual output of distributed power generation is established;

[0280] According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

[0281] Preferably, the first power outage time calculation unit is specifically configured to:

[0282] When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0;

[0283] When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

[0284] Preferably, the second power outage time calculation unit is specifically configured to:

[0285] If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time;

[0286] Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area;

[0287] Calculating a first power supply time of the first distributed power supply according to the first power supply rate;

[0288] A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

[0289] Preferably, the third power outage time calculation unit is specifically configured to:

[0290] If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time;

[0291] Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area;

[0292] calculating a second power supply time of the second distributed power supply according to the second power supply rate;

[0293] The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

[0294] A reliability measurement system for a multi-source distribution network provided by an embodiment of the present invention can consider multiple multi-source active island division methods according to different fault scenarios and the output conditions of distributed power sources, so that the measurement results are more accurate and more in line with the current distributed power supply conditions.

[0295] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0296] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A reliability calculation method for a multi-source distribution network, characterized in that: include: Obtaining first connection elements and upstream and downstream relationships between feeder areas of a multi-source distribution network, and second connection elements of distributed power sources connected to feeder areas; In a preset fault scenario, based on the first connection element and the upstream and downstream relationship, a fault area is screened from the feeder areas of the multi-source distribution network, and an upstream feeder area of ​​the fault area is obtained; Dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area to obtain at least one set of islanding modes in the fault area and the downstream feeder area, respectively; the islanding modes include microgrid islanding and multi-source islanding; Calculating the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario based on the output data of the distributed power sources and the islanding mode, and obtaining the reliability of the multi-source distribution network; The method of screening, in a preset fault scenario, obtaining a fault area from feeder areas of a multi-source distribution network according to the first connection element and the upstream and downstream relationship, and obtaining an upstream feeder area of ​​the fault area includes: In a preset line fault scenario, locating a feeder area where the line fault exists in the multi-source distribution network as a fault area, and obtaining an upstream feeder area of ​​the fault area according to the upstream and downstream relationship; In a preset component failure scenario, the feeder area with line faults is located from the multi-source distribution network as the initial fault area; The initial fault area is updated according to the first connection element and the upstream and downstream relationship to obtain a fault area, and an upstream feeder area of ​​the fault area is obtained according to the upstream and downstream relationship.

2. The reliability calculation method of a multi-source distribution network according to claim 1, characterized in that: The updating of the initial fault area according to the first connection element and the upstream-downstream relationship to obtain a fault area, and obtaining an upstream feeder area of ​​the fault area according to the upstream-downstream relationship, includes: According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained; If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area; If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone; According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

3. The reliability calculation method of a multi-source distribution network according to claim 1, characterized in that: The dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area to obtain at least one set of island modes in the fault area and the downstream feeder area, respectively, includes: If the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes in the fault area; If the fault area includes less than two feeder areas, the islanding mode of the fault area is a microgrid islanding mode; If the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of island modes in the downstream feeder area; If the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

4. The reliability calculation method of a multi-source distribution network according to claim 3, characterized in that: If the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes in the fault area includes: Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone; In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

5. The reliability calculation method of a multi-source distribution network according to claim 3, characterized in that: If the downstream feeder area of ​​the fault area includes no less than two feeder areas, dynamically adjusting the on / off states of the first connection element and the second connection element in the downstream feeder area to obtain at least one set of island modes in the downstream feeder area includes: Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition; In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

6. The reliability calculation method of a multi-source distribution network according to claim 1, characterized in that: The calculating, based on the output data of the distributed power sources and the islanding mode, the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario to obtain the reliability of the multi-source distribution network includes: Obtain output data of distributed power sources; Obtaining, according to the type of the first connection element at the entrance of the fault area, a first power outage time of the upstream feeder area under the fault scenario; Calculating a second power outage time of the fault area under the fault scenario according to the output data of the distributed power source connected in the island mode of the fault area; Calculating a third power outage time of the downstream feeder area under the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area; The reliability of the multi-source power distribution network is obtained according to the first power outage time, the second power outage time, and the third power outage time.

7. The reliability calculation method of a multi-source distribution network according to claim 6, characterized in that: The obtaining of the output data of the distributed power source includes: Obtain historical samples of predicted output deviations of distributed power sources; Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample; Establishing a fuzzy set of actual output of distributed power sources according to the mean and variance of the historical samples; According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

8. The reliability calculation method of a multi-source distribution network according to claim 6, characterized in that: The obtaining, according to the type of the first connection element at the entrance of the fault area, a first power outage time of the upstream feeder area in the fault scenario includes: When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0; When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

9. The reliability calculation method of a multi-source distribution network according to claim 6, characterized in that: The calculating, based on the output data of the distributed power supply connected in the island mode of the fault area, the second power outage time of the fault area in the fault scenario includes: If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time; Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area; Calculating a first power supply time of the first distributed power supply according to the first power supply rate; A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

10. The reliability calculation method of a multi-source distribution network according to claim 6, characterized in that: The calculating, based on the output data of the distributed power source connected in the island mode of the downstream feeder area, the third power outage time of the downstream feeder area in the fault scenario includes: If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time; Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area; calculating a second power supply time of the second distributed power supply according to the second power supply rate; The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

11. A reliability measurement system for a multi-source distribution network, characterized in that: include: A physical connection relationship acquisition module is used to obtain the first connection elements and upstream and downstream relationships between the feeder areas of the multi-source distribution network, and the second connection elements of the distributed power supply access feeder area; a fault and upstream zoning module, configured to, under a preset fault scenario, screen the feeder areas of the multi-source distribution network to obtain a fault area and obtain an upstream feeder area of ​​the fault area based on the first connection element and the upstream and downstream relationships; a dynamic islanding division module, configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area and its downstream feeder area, to obtain at least one set of islanding modes for the fault area and the downstream feeder area, respectively; the islanding modes include microgrid islanding and multi-source islanding; A reliability calculation module is used to calculate the power outage time of the fault area, the upstream feeder area, and the downstream feeder area under the fault scenario based on the output data of the distributed power source and the island mode, so as to obtain the reliability of the multi-source distribution network; The fault and upstream partitioning module includes: A first partitioning unit is configured to locate, in a preset line fault scenario, a feeder area where a line fault exists in the multi-source distribution network as a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship; An initial fault area locating unit is used to locate a feeder area with a line fault in a multi-source distribution network as an initial fault area under a preset component failure scenario; The second partitioning unit is configured to update the initial fault area according to the first connection element and the upstream and downstream relationship to obtain a fault area, and obtain an upstream feeder area of ​​the fault area according to the upstream and downstream relationship.

12. A reliability measurement system for a multi-source distribution network according to claim 11, characterized in that: The second partition division unit is specifically used to: According to the upstream and downstream relationship, an adjacent upstream feeder area of ​​the initial fault area is obtained; If the first connection element at the entrance of the adjacent upstream feeder area is a circuit breaker, the initial fault area is used as the fault area; If the first connection element at the entrance of the adjacent upstream feeder zone is a section switch, the adjacent upstream feeder zone is merged into the initial fault zone until the first connection element at the entrance of the adjacent upstream feeder zone of the new initial fault zone is a circuit breaker, and the latest initial fault zone is used as the fault zone; According to the upstream and downstream relationship, the upstream feeder area of ​​the fault area is obtained.

13. The reliability calculation system for a multi-source distribution network according to claim 10, characterized in that: The dynamic island division module includes: a first fault area island determination unit, configured to dynamically adjust the on / off states of the first connection element and the second connection element in the fault area to obtain at least one set of island modes for the fault area if the fault area includes no less than two feeder areas; a second fault area islanding determination unit, configured to determine that the islanding mode of the fault area is a microgrid islanding mode if the fault area includes less than two feeder areas; a first downstream island determining unit, configured to dynamically adjust the on / off states of the first connecting element and the second connecting element in the downstream feeder area if the downstream feeder area of ​​the fault area includes no less than two feeder areas, to obtain at least one set of island modes for the downstream feeder area; The second downstream island determining unit is configured to determine that, if the downstream feeder area of ​​the fault area includes less than two feeder areas, the islanding mode of the downstream feeder area is a microgrid islanding mode.

14. The reliability calculation system for a multi-source distribution network according to claim 13, characterized in that: The first fault area island determination unit is specifically configured to: Dynamically adjusting the on / off state of the first connection element in the fault zone to reconstruct the fault zone to obtain at least one fault partition mode; the fault partition mode includes at least one fault sub-zone; In a fault partition mode, the on-off state of the second connection element in the fault zone is dynamically adjusted to change the number of distributed power sources connected to the fault sub-zone, thereby obtaining an island mode corresponding to each fault sub-zone.

15. The reliability measurement system of a multi-source distribution network according to claim 13, characterized in that: The first downstream island determining unit is specifically configured to: Dynamically adjusting the on / off state of the first connection element in the downstream feeder area of ​​the fault area to reconstruct the downstream feeder area to obtain at least one downstream partition mode; the downstream partition mode includes at least one downstream sub-partition; In a downstream partition mode, the on-off state of the second connection element in the downstream feeder area is dynamically adjusted to change the number of distributed power sources connected to the downstream sub-area, thereby obtaining an island mode corresponding to each downstream sub-area.

16. The reliability measurement system of a multi-source distribution network according to claim 10, characterized in that: The reliability calculation module includes: An output data acquisition unit, used to acquire output data of a distributed power source; a first power outage time calculation unit, configured to obtain a first power outage time of the upstream feeder area under the fault scenario according to a type of the first connection element at the entrance of the fault area; A second power outage time calculation unit is configured to calculate a second power outage time of the fault area under the fault scenario based on the output data of the distributed power source connected in the island mode of the fault area; A third power outage time calculation unit is configured to calculate a third power outage time of the downstream feeder area under the fault scenario based on the output data of the distributed power source connected in the island mode of the downstream feeder area; The reliability calculation unit is used to obtain the reliability of the multi-source distribution network according to the first power outage time, the second power outage time and the third power outage time.

17. The reliability calculation system for a multi-source distribution network according to claim 16, characterized in that: The output data acquisition unit is specifically used to: Obtain historical samples of predicted output deviations of distributed power sources; Calculating the first-order moment estimate and the second-order moment estimate of the historical sample to obtain the mean and variance of the historical sample; According to the mean and variance of the historical samples, a fuzzy set of actual output of distributed power generation is established; According to the fuzzy set and the installed capacity of the distributed power source, the actual output of the distributed power source is obtained as output data.

18. The reliability calculation system for a multi-source distribution network according to claim 16, characterized in that: The first power outage time calculation unit is specifically configured to: When the first connection element at the entrance of the fault zone is a circuit breaker, the first power outage time of the upstream feeder zone in the fault scenario is 0; When the first connecting element at the entrance of the fault area is a section switch, the first power outage time of the upstream feeder area in the fault scenario is the isolation time.

19. The reliability calculation system for a multi-source distribution network according to claim 16, characterized in that: The second power outage time calculation unit is specifically configured to: If no distributed power source is connected to the fault area in the island mode, the second power outage time of the fault area in the fault scenario is the fault repair time; Otherwise, calculating a first power supply rate of the first distributed power source according to the first output data of the first distributed power source connected in the island mode of the fault area; Calculating a first power supply time of the first distributed power supply according to the first power supply rate; A second power outage time of the fault area in the fault scenario is calculated according to the isolation time, the fault repair time and the first power supply time.

20. The reliability calculation system for a multi-source distribution network according to claim 16, characterized in that: The third power outage time calculation unit is specifically configured to: If no distributed power source is connected to the downstream feeder area in the island mode, the third power outage time of the downstream feeder area in the fault scenario is the fault repair time; Otherwise, calculating a second power supply rate of the second distributed power source according to the second output data of the second distributed power source connected in the island mode of the downstream feeder area; calculating a second power supply time of the second distributed power supply according to the second power supply rate; The third power outage time of the downstream feeder area in the fault scenario is calculated according to the isolation time, the fault transfer time and the second power supply time.

21. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the reliability calculation method of a multi-source distribution network according to any one of claims 1 to 10.

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