State evaluation method and system for accessing distributed power supply to power distribution network

Abstract

The invention provides a state evaluation method and system for a distributed power supply access power distribution network, and the method comprises the steps: obtaining each index value of state operation data under a state evaluation index system according to the state operation data of the distributed power supply access power distribution network; based on each index value of the state operation data in a state evaluation index system, calculating a comprehensive evaluation index value of the distributed power supply connected to the power distribution network by using a variable coefficient method; according to the comprehensive evaluation index value of the distributed power supply access power distribution network, performing state evaluation on the distributed power supply access power distribution network; according to the invention, under the state evaluation index system, the weight of each index in the system is calculated by using the variable coefficient method, so that the state evaluation of the distributed power supply access power distribution network is realized, the stability and reliability of the distributed power supply access power distribution network are improved, and the stable operation of the power grid is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution networks, and particularly relates to a method and system for state evaluation of distributed power sources accessing distribution networks. Background Art

[0002] At present, the access of distributed power sources to distribution networks, as an important component form in the development process of smart grids, can solve the problem of power supply for a large number of loads. However, after the access of distributed power sources to the original distribution system, the traditional distribution network becomes an active network, which will change the original network topology and power flow distribution, and further affect the network loss, voltage distribution and reliability in the power grid. Therefore, when a large number of distributed power sources access the distribution network, it is necessary to conduct a state evaluation of the distribution network to reduce the negative effects of high-proportion distributed power sources accessing the distribution network;

[0003] Traditional state evaluation methods for distribution networks have a single index and lack a systematic evaluation method in evaluation, resulting in more and more obvious instability factors in the power grid as the power structure becomes more complex, posing a greater threat to the safety and stability of the distribution network, and thus affecting the reliability of the distribution network. Summary of the Invention

[0004] In order to solve the problem of low evaluation reliability caused by a single index when conducting a state evaluation of a distribution network in the prior art, the present invention proposes a method for state evaluation of distributed power sources accessing a distribution network, including:

[0005] Obtaining each index value of the state operation data under a state evaluation index system according to the state operation data of distributed energy accessing the distribution network;

[0006] Based on each index value of the state operation data under the state evaluation index system, calculating the comprehensive evaluation index value of the distributed power source accessing the distribution network by using the coefficient of variation method;

[0007] Conducting a state evaluation of the distributed power source accessing the distribution network according to the comprehensive evaluation index value of the distributed power source accessing the distribution network.

[0008] Optionally, the state evaluation index system includes: reliability index, safety index, adaptability index and flexibility index;

[0009] Among them, the reliability index includes: power supply reliability, average failure rate, outage duration and average outage time;

[0010] The safety index includes: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content and short-circuit capacity;

[0011] The adaptability indicators include: voltage adaptability, frequency adaptability, network loss adaptability, dispatching operation adaptability, and fault recovery adaptability;

[0012] The flexibility indicators include: capacity flexibility, access mode flexibility, response speed flexibility, and expansion flexibility.

[0013] Optionally, based on the index values of the state operation data under the state evaluation index system, using the coefficient of variation method to calculate the comprehensive evaluation index value of the distributed power source connected to the distribution network, including:

[0014] Based on the index values of the state operation data under the state evaluation index system, using the coefficient of variation method to calculate the weights corresponding to each index;

[0015] According to the index values of the state operation data under the state evaluation index system and the weights corresponding to each index value, obtain the comprehensive evaluation index value of the distributed power source connected to the distribution network.

[0016] Optionally, based on the index values of the state operation data under the state evaluation index system, using the coefficient of variation method to calculate the weights corresponding to each index, including:

[0017] Based on the index values of the state operation data under the state evaluation index system, establish an original index matrix;

[0018] According to the original index matrix, obtain the mean and standard deviation of each index in the original index matrix;

[0019] According to the mean and standard deviation corresponding to each index in the original index matrix, calculate the coefficient of variation of each index;

[0020] Perform normalization processing on the coefficient of variation of each index to obtain the weights corresponding to each index.

[0021] Optionally, the expression for calculating the coefficient of variation corresponding to each index according to the mean and standard deviation corresponding to each index in the original index matrix is as follows:

[0022]

[0023] where, w k represents the coefficient of variation of the kth index; T k represents the standard deviation of the kth index in the original index matrix; y k represents the variance of the kth index in the original index matrix; n represents the number of indexes.

[0024] Optionally, based on the comprehensive evaluation index value of the distributed power source connected to the distribution network, the state of the distributed power source connected to the distribution network is as follows:

[0025] Match the corresponding state evaluation level in the preset state evaluation information according to the comprehensive evaluation index value of the distributed power source connected to the distribution network;

[0026] Determine the state evaluation result of the distributed power source connected to the distribution network according to the state evaluation level.

[0027] Based on the same inventive concept, the present invention also provides a state evaluation system for a distributed power source connected to a distribution network, including:

[0028] An index system construction module: used to obtain each index value of the state operation data under the state evaluation index system according to the state operation data of the distributed energy connected to the distribution network;

[0029] A comprehensive index calculation module: used to calculate the comprehensive evaluation index value of the distributed power source connected to the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system;

[0030] A state evaluation module: used to perform state evaluation on the distributed power source connected to the distribution network according to the comprehensive evaluation index value of the distributed power source connected to the distribution network.

[0031] Optionally, the state evaluation index system in the index system construction module includes: reliability index, safety index, adaptability index and flexibility index;

[0032] Among them, the reliability index includes: power supply reliability, average failure rate, outage duration and average outage time;

[0033] The safety index includes: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content and short-circuit capacity;

[0034] The adaptability index includes: voltage adaptability, frequency adaptability, line loss adaptability, dispatching operation adaptability and fault recovery adaptability;

[0035] The flexibility index includes: capacity flexibility, access mode flexibility, response speed flexibility and expansion flexibility.

[0036] Optionally, the comprehensive index calculation module is specifically used for:

[0037] Calculate the weight corresponding to each index by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system;

[0038] Obtain the comprehensive evaluation index value of the distributed power source connected to the distribution network according to each index value of the state operation data under the state evaluation index system and the weight corresponding to each index value.

[0039] Optionally, the comprehensive index calculation module calculates the weight corresponding to each index based on the index value of the state operation data under the state evaluation index system by using the coefficient of variation method, including:

[0040] Based on the indicator values ​​of the state operation data under the state evaluation indicator system, an original indicator matrix is ​​established;

[0041] According to the original indicator matrix, the mean and standard deviation of each indicator in the original indicator matrix are obtained;

[0042] Calculate the coefficient of variation of each indicator according to the mean and standard deviation corresponding to each indicator in the original indicator matrix;

[0043] The coefficient of variation of each indicator is normalized to obtain the weight corresponding to each indicator.

[0044] Optionally, the comprehensive indicator calculation module calculates the expression corresponding to the coefficient of variation of each indicator according to the mean and standard deviation corresponding to each indicator in the original indicator matrix as follows:

[0045]

[0046] Among them, w k represents the coefficient of variation of the kth indicator; T k represents the standard deviation of the kth indicator of the original indicator matrix; y k represents the variance of the kth indicator of the original indicator matrix; n represents the number of indicators.

[0047] Optionally, the status assessment module is specifically used to:

[0048] According to the comprehensive evaluation index value of the distributed power source connected to the distribution network, matching the corresponding status evaluation level in the preset status evaluation information;

[0049] According to the status assessment level, a status assessment result of the distributed power source being connected to the power distribution network is determined.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention provides a method and system for state assessment of distributed power sources connected to a distribution network, including: obtaining each index value of the state operation data under a state assessment index system according to the state operation data of distributed energy connected to the distribution network; calculating the comprehensive evaluation index value of the distributed power source connected to the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state assessment index system; performing state assessment on the distributed power source connected to the distribution network according to the comprehensive evaluation index value of the distributed power source connected to the distribution network. Under the state assessment index system, the present invention calculates the weight of each index in the system by using the coefficient of variation method, thereby realizing the state assessment of the distributed power source connected to the distribution network, which is beneficial to improving the stability and reliability of the distribution network connected to the distributed power source and ensuring the stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic flowchart of a method for state assessment of a distributed power source connected to a distribution network provided by the present invention;

[0053] Figure 2 It is a schematic diagram of a state assessment index system in a method for state assessment of a distributed power source connected to a distribution network provided by the present invention;

[0054] Figure 3 It is a schematic diagram of the structural composition of a state assessment system for a distributed power source connected to a distribution network provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The present invention proposes a method and system for state assessment of distributed power sources connected to a distribution network. The following further describes the specific embodiments of the present invention in detail with reference to the drawings.

[0056] Embodiment 1:

[0057] A method for state assessment of a distributed power source connected to a distribution network, the schematic flowchart is as Figure 1 shown, including:

[0058] Step 1: Obtaining each index value of the state operation data under a state assessment index system according to the state operation data of distributed energy connected to the distribution network;

[0059] Step 2: Calculating the comprehensive evaluation index value of the distributed power source connected to the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state assessment index system;

[0060] Step 3: Performing state assessment on the distributed power source connected to the distribution network according to the comprehensive evaluation index value of the distributed power source connected to the distribution network.

[0061] Specifically, as Figure 2As shown, the state evaluation index system in Step 1 includes: reliability index, safety index, adaptability index, and flexibility index;

[0062] Among them, the reliability index includes: power supply reliability, average failure rate, outage duration, and average outage time;

[0063] The safety index includes: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content, and short-circuit capacity;

[0064] The adaptability index includes: voltage adaptability, frequency adaptability, network loss adaptability, dispatching operation adaptability, and fault recovery adaptability;

[0065] The flexibility index includes: capacity flexibility, access mode flexibility, response speed flexibility, and expansion flexibility.

[0066] Step 2 includes:

[0067] Based on the index values of each index in the state evaluation index system for the state operation data, use the coefficient of variation method to calculate the weights corresponding to each index;

[0068] According to the index values of each index in the state evaluation index system for the state operation data and the weights corresponding to each index value, obtain the comprehensive evaluation index value of the distributed power source connected to the distribution network.

[0069] The using the coefficient of variation method to calculate the weights corresponding to each index based on the index values of each index in the state evaluation index system for the state operation data includes:

[0070] Based on the index values of each index in the state evaluation index system for the state operation data, establish an original index matrix;

[0071] According to the original index matrix, obtain the mean and standard deviation of each index in the original index matrix;

[0072] According to the mean and standard deviation corresponding to each index in the original index matrix, calculate the coefficient of variation of each index;

[0073] Normalize the coefficient of variation of each index to obtain the weights corresponding to each index.

[0074] The expression for calculating the coefficient of variation of each index according to the mean and standard deviation corresponding to each index in the original index matrix is as follows:

[0075]

[0076] Among them, w k represents the coefficient of variation of the kth index; T kdenotes the standard deviation of the k-th index of the original index matrix; y k denotes the variance of the k-th index of the original index matrix; n denotes the number of indices.

[0077] Step 3 includes:

[0078] According to the comprehensive evaluation index value of the distributed power source connected to the distribution network, match the corresponding state evaluation level in the preset state evaluation information;

[0079] According to the state evaluation level, determine the state evaluation result of the distributed power source connected to the distribution network; preferably, the state evaluation levels include: major risk level, relatively large risk level, general risk level, minor risk level, and risk-free.

[0080] By constructing a multi-dimensional state evaluation index system, the present invention comprehensively considers the influencing factors of the operation state of the distribution network with distributed energy access from four dimensions: reliability, security, adaptability, and flexibility, which can improve the comprehensiveness of the distribution network operation state evaluation, and uses the coefficient of variation method to calculate the weights of the various indices in the state evaluation index system, so that the obtained comprehensive weights can have both integrity and rationality, which can improve the accuracy of the state evaluation of the distributed power source connected to the distribution network, and thus ensure the stable operation of the power grid.

[0081] Embodiment 2:

[0082] Based on the same inventive concept, the present invention also provides a state evaluation system for a distributed power source connected to a distribution network. The schematic structural composition diagram is as Figure 3 shown, and includes:

[0083] Index system construction module: used to obtain the values of the various indices of the state operation data under the state evaluation index system according to the state operation data of the distributed energy connected to the distribution network;

[0084] Comprehensive index calculation module: used to calculate the comprehensive evaluation index value of the distributed power source connected to the distribution network by using the coefficient of variation method based on the values of the various indices of the state operation data under the state evaluation index system;

[0085] State evaluation module: used to perform state evaluation on the distributed power source connected to the distribution network according to the comprehensive evaluation index value of the distributed power source connected to the distribution network.

[0086] The state evaluation index system in the index system construction module includes: reliability index, security index, adaptability index, and flexibility index;

[0087] Among them, the reliability index includes: power supply reliability, average failure rate, outage duration, and average outage time;

[0088] The safety indicators include: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content, and short-circuit capacity;

[0089] The adaptability indicators include: voltage adaptability, frequency adaptability, network loss adaptability, dispatching operation adaptability, and fault recovery adaptability;

[0090] The flexibility indicators include: capacity flexibility, access mode flexibility, response speed flexibility, and expansion flexibility.

[0091] The comprehensive index calculation module is specifically used for:

[0092] Based on the values of each indicator in the state evaluation index system for the state operation data, the coefficient of variation method is used to calculate the weight corresponding to each indicator;

[0093] According to the values of each indicator in the state evaluation index system for the state operation data and the weights corresponding to the values of each indicator, the comprehensive evaluation index value of the distributed power source connected to the distribution network is obtained.

[0094] In the comprehensive index calculation module, based on the values of each indicator in the state evaluation index system for the state operation data, using the coefficient of variation method to calculate the weight corresponding to each indicator includes:

[0095] Based on the values of each indicator in the state evaluation index system for the state operation data, an original indicator matrix is established;

[0096] According to the original indicator matrix, the mean and standard deviation of each indicator in the original indicator matrix are obtained;

[0097] According to the mean and standard deviation corresponding to each indicator in the original indicator matrix, the coefficient of variation of each indicator is calculated;

[0098] The coefficient of variation of each indicator is normalized to obtain the weight corresponding to each indicator.

[0099] The expression for calculating the coefficient of variation of each indicator according to the mean and standard deviation corresponding to each indicator in the original indicator matrix in the comprehensive index calculation module is as follows:

[0100]

[0101] where, w k represents the coefficient of variation of the kth indicator; T k represents the standard deviation of the kth indicator in the original indicator matrix; y k represents the variance of the kth indicator in the original indicator matrix; n represents the number of indicators.

[0102] The state evaluation module is specifically used for:

[0103] Match the corresponding state evaluation level in the preset state evaluation information according to the comprehensive evaluation index value of the distributed power source accessing the distribution network;

[0104] Determine the state evaluation result of the distributed power source accessing the distribution network according to the state evaluation level.

[0105] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0106] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 or a device for implementing the functions specified in one or more of the blocks.

[0107] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device implements the functions specified in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 or a device for implementing the functions specified in one or more of the blocks.

[0108] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more of the processes Figure 1 one process or multiple processes and / or blocks Figure 1 or a device for implementing the functions specified in one or more of the blocks.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the present invention, various changes, modifications or equivalent substitutions can still be made to the specific implementation manners of the application. However, these changes, modifications or equivalent substitutions are all within the scope of protection of the claims pending for approval of the application.

Claims

1. A method for state assessment of distributed power sources connected to a distribution network, characterized in that, Including: Obtaining each index value of the state operation data under the state evaluation index system according to the state operation data of distributed energy accessing the distribution network; Calculating the comprehensive evaluation index value of the distributed power source accessing the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system; Conducting a state evaluation on the distributed power source accessing the distribution network according to the comprehensive evaluation index value of the distributed power source accessing the distribution network.

2. The method according to claim 1, characterized in that, The state evaluation index system includes: reliability index, safety index, adaptability index, and flexibility index; Among them, the reliability index includes: power supply reliability, average failure rate, outage duration, and average outage time; The safety index includes: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content, and short-circuit capacity; The adaptability index includes: voltage adaptability, frequency adaptability, line loss adaptability, dispatching operation adaptability, and fault recovery adaptability; The flexibility index includes: capacity flexibility, access mode flexibility, response speed flexibility, and expansion flexibility.

3. The method according to claim 1, characterized in that, The calculating the comprehensive evaluation index value of the distributed power source accessing the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system includes: Calculating the weight corresponding to each index by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system; Obtaining the comprehensive evaluation index value of the distributed power source accessing the distribution network according to each index value of the state operation data under the state evaluation index system and the weight corresponding to each index value.

4. The method according to claim 3, characterized in that, The calculating the weight corresponding to each index by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system includes: Based on each index value of the state operation data under the state evaluation index system, establishing an original index matrix; Obtaining the mean and standard deviation of each index in the original index matrix according to the original index matrix; Calculating the coefficient of variation of each index according to the mean and standard deviation corresponding to each index in the original index matrix; Normalizing the coefficient of variation of each index to obtain the weight corresponding to each index.

5. The method according to claim 4, characterized in that, The expression for calculating the coefficient of variation corresponding to each index according to the mean and standard deviation corresponding to each index in the original index matrix is as follows: Among them, w k represents the coefficient of variation of the k-th index; T k represents the standard deviation of the k-th index of the original index matrix; y k represents the variance of the k-th index of the original index matrix; n represents the number of indices.

6. The method according to claim 1, characterized in that, The conducting a state on the distributed power source accessing the distribution network according to the comprehensive evaluation index value of the distributed power source accessing the distribution network includes: Matching the corresponding state evaluation level in the preset state evaluation information according to the comprehensive evaluation index value of the distributed power source accessing the distribution network; Determining the state evaluation result of the distributed power source accessing the distribution network according to the state evaluation level.

7. A state assessment system for distributed power sources connected to a distribution network, characterized in that, Including: Index system construction module: used for obtaining each index value of the state operation data under the state evaluation index system according to the state operation data of distributed energy accessing the distribution network; Comprehensive index calculation module: used for calculating the comprehensive evaluation index value of the distributed power source accessing the distribution network by using the coefficient of variation method based on each index value of the state operation data under the state evaluation index system; Status evaluation module: used to perform status evaluation on the distributed power source connected to the distribution network according to the comprehensive evaluation index value of the distributed power source connected to the distribution network.

8. The system according to claim 7, characterized in that, The status evaluation index system in the index system construction module includes: reliability index, safety index, adaptability index, and flexibility index; Among them, the reliability index includes: power supply reliability, average failure rate, outage duration, and average outage time; The safety index includes: voltage deviation, frequency deviation, three-phase unbalance degree, harmonic content, and short-circuit capacity; The adaptability index includes: voltage adaptability, frequency adaptability, network loss adaptability, dispatching operation adaptability, and fault recovery adaptability; The flexibility index includes: capacity flexibility, access mode flexibility, response speed flexibility, and expansion flexibility.

9. The system according to claim 7, wherein, The comprehensive index calculation module is specifically used for: Based on the index values of the status operation data under the status evaluation index system, using the coefficient of variation method to calculate the weights corresponding to each index; According to the index values of the status operation data under the status evaluation index system and the weights corresponding to the index values, obtain the comprehensive evaluation index value of the distributed power source connected to the distribution network.

10. The system according to claim 7, wherein, The status evaluation module is specifically used for: According to the comprehensive evaluation index value of the distributed power source connected to the distribution network, match the corresponding status evaluation level in the preset status evaluation information; According to the status evaluation level, determine the status evaluation result of the distributed power source connected to the distribution network.

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