A reliability calculation method and terminal of a distributed photovoltaic access power distribution network

Abstract

The application discloses a kind of reliability calculation method and terminal of distributed photovoltaic access distribution network, obtain the fault duration of distribution network, and based on this and the effective output time of distributed photovoltaic, the user outage duration of distributed photovoltaic reduction is calculated;Further, the equivalent outage user number of distributed photovoltaic reduction is calculated according to the average capacity of distribution network user and load capacity ratio.Calculating the outage time of photovoltaic output reduction according to the calculated user outage duration and equivalent outage user number, in this way, the reduction of user outage time by quantification calculation distributed photovoltaic, to accurately evaluate the power supply reliability level of distribution network after considering distributed photovoltaic access, realize the lean evaluation of power supply reliability.

Description

Technical Field

[0001] This invention relates to the technical field of distribution network reliability assessment, and in particular to a reliability calculation method and terminal for a distribution network with distributed photovoltaic access. Background Technology

[0002] Currently, power supply reliability reflects the ability of a power supply system to continuously supply power to users. For a long time, power supply companies have used continuous voltage interruption as an indicator for evaluating power supply reliability.

[0003] With the advancement of new power system construction, new energy sources such as distributed photovoltaic (PV) power have been widely applied, and distribution networks are transforming into intelligent grids that can accommodate a large number of distributed power sources, microgrids, and other new user-side loads. However, due to the random and intermittent nature of distributed PV output, there is currently no accurate method for quantifying the impact of distributed PV output on the reliability of distribution network power supply, nor for integrating it with existing power supply reliability assessment systems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and terminal for calculating the reliability of a distribution network with distributed photovoltaic access, which can accurately evaluate the power supply reliability level after distributed photovoltaic access to the distribution network.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for calculating the reliability of a distribution network with distributed photovoltaic (PV) grid integration, comprising the following steps:

[0007] S1. Calculate the duration of user power outages reduced by distributed photovoltaic power generation based on the obtained fault duration of the distribution network and the effective output time of distributed photovoltaic power generation.

[0008] S2. Calculate the total capacity of the distribution network and the average capacity of the distribution network users. Calculate the equivalent number of power outage users reduced by distributed photovoltaic power based on the average capacity of the distribution network users and the load factor.

[0009] S3. Calculate the power outage time for photovoltaic power output reduction by combining the user outage duration of the distributed photovoltaic power reduction and the equivalent number of outage users;

[0010] S4. Obtain the outage time of the power distribution network, subtract the outage time caused by the reduction in photovoltaic output from the outage time of the outage time to obtain the average outage time of users in the distributed photovoltaic power distribution network, and determine the reliability of the power distribution network through the average outage time of users.

[0011] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is as follows:

[0012] A reliability calculation terminal for a distributed photovoltaic (PV) grid includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the various steps of the aforementioned reliability calculation method for a distributed PV grid.

[0013] The beneficial effects of this invention are as follows: It obtains the fault duration of the distribution network and calculates the user outage duration reduced by distributed photovoltaic (PV) power based on this and the effective output time of distributed PV; further, it calculates the equivalent number of outage users reduced by distributed PV power based on the average capacity and load factor of distribution network users. By calculating the outage time reduced by PV power output based on the calculated user outage duration and the equivalent number of outage users, the reduction of user outage time by distributed PV power is quantitatively calculated, thereby accurately evaluating the power supply reliability level of the distribution network after considering distributed PV integration, and achieving a refined evaluation of power supply reliability. Attached Figure Description

[0014] Figure 1 This is a flowchart illustrating a method for calculating the reliability of a distribution network with distributed photovoltaic access, according to an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of a reliability calculation terminal for a distribution network with distributed photovoltaic access, according to an embodiment of the present invention.

[0016] Figure 3 This is a flowchart illustrating the specific steps of a method for calculating the reliability of a distribution network with distributed photovoltaic access, as described in an embodiment of the present invention.

[0017] Label Explanation:

[0018] 1. A reliability calculation terminal for a distribution network with distributed photovoltaic access; 2. A memory; 3. A processor. Detailed Implementation

[0019] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0020] Please refer to Figure 1 This invention provides a method for calculating the reliability of a distribution network with distributed photovoltaic (PV) grid integration, comprising the following steps:

[0021] S1. Calculate the duration of user power outages reduced by distributed photovoltaic power generation based on the obtained fault duration of the distribution network and the effective output time of distributed photovoltaic power generation.

[0022] S2. Calculate the total capacity of the distribution network and the average capacity of the distribution network users. Calculate the equivalent number of power outage users reduced by distributed photovoltaic power based on the average capacity of the distribution network users and the load factor.

[0023] S3. Calculate the power outage time for photovoltaic power output reduction by combining the user outage duration of the distributed photovoltaic power reduction and the equivalent number of outage users;

[0024] S4. Obtain the outage time of the power distribution network, subtract the outage time caused by the reduction in photovoltaic output from the outage time of the outage time to obtain the average outage time of users in the distributed photovoltaic power distribution network, and determine the reliability of the power distribution network through the average outage time of users.

[0025] As described above, the beneficial effects of this invention are as follows: It obtains the fault duration of the distribution network and calculates the user outage duration reduced by distributed photovoltaic (PV) power based on this and the effective output time of distributed PV; further, it calculates the equivalent number of outage users reduced by distributed PV power based on the average capacity and load factor of the distribution network users. By calculating the outage time reduced by PV power output based on the calculated user outage duration and the equivalent number of outage users, the reduction of user outage time by distributed PV power is quantitatively calculated, thereby accurately evaluating the power supply reliability level of the distribution network after considering distributed PV integration, and achieving a refined evaluation of power supply reliability.

[0026] Further, prior to step S1, the following is included:

[0027] Collect the fault start time Ts and fault repair time Tr of the distribution network, and obtain the fault duration Tm of the distribution network, where Tm = Tr - Ts.

[0028] Further, step S1 includes:

[0029] The total duration during which the output coefficient of distributed photovoltaic (PV) is greater than a preset proportion during the fault duration of the distribution network is taken as the effective output time Tpv of distributed PV, where the preset proportion is 80%.

[0030] The duration of user power outages reduced by distributed photovoltaic power generation is calculated based on the fault duration Tm of the distribution network and the effective output time Tpv of the distributed photovoltaic power generation system. Tpvs = Tm - Tpv.

[0031] As described above, the total duration during which the output coefficient of distributed photovoltaic (PV) is greater than a preset ratio during the fault duration is taken as the effective output time of distributed PV. When the output coefficient of distributed PV is greater than this preset ratio, its output is stable and effective. Therefore, the determined effective output time of distributed PV can effectively avoid the intermittency and fluctuation of distributed PV output. Furthermore, the reduction of power outage time for users by distributed PV can be quantified by subsequent formula calculations.

[0032] Further, the equivalent number of power outages reduced by distributed photovoltaic power generation is calculated based on the average capacity and load factor of the distribution network users, including:

[0033] The load-capacity ratio c is obtained by dividing the system power supply of the distribution network by the total system capacity and then by the first preset coefficient.

[0034] Calculate the equivalent number of power outages u1 caused by distributed photovoltaic power generation based on the average capacity 'a' and the carrying capacity ratio 'c' of the distribution network users:

[0035] u1 = p × V × I1 / c / a;

[0036] In the formula, p represents the second preset coefficient, V represents the nominal voltage, and I1 represents the fault current change value.

[0037] As described above, by quantifying the equivalent number of users experiencing power outages due to distributed photovoltaic (PV) power generation, it is possible to subsequently calculate the reduction in power outage time caused by distributed PV power output.

[0038] Further, step S3 includes:

[0039] The product of the user power outage duration calculated for each power outage and the equivalent number of users experiencing power outages;

[0040] Divide the cumulative calculation result by the total number of users in the distribution network to obtain the outage time due to the reduction in photovoltaic output.

[0041] As described above, by calculating the product of the equivalent number of users experiencing power outages for each outage and the corresponding duration of photovoltaic power output reduction, and then dividing by the total number of users, the average outage time due to photovoltaic power output reduction can be obtained, which is convenient for subsequent calculations that take into account the average outage time of distributed photovoltaic power output users.

[0042] Furthermore, the fault outage time of the distribution network is obtained, including:

[0043] Obtain the power outage time and the actual number of users affected by each fault in the power distribution network;

[0044] The product of the power outage time and the actual number of users experiencing power outages for each fault;

[0045] Divide the cumulative calculation result by the total number of users in the distribution network to obtain the power outage time of the distribution network.

[0046] As described above, the average outage time of the distribution network can be obtained by multiplying the outage time of each fault in the distribution network with the actual number of users experiencing power outages. By accumulating the results of each multiplication calculation and then dividing by the total number of users, the average outage time of the distribution network can be obtained. This is useful for subsequent calculations that take into account the average outage time of distributed photovoltaic power generation users.

[0047] Furthermore, determining the reliability of the distribution network through the average power outage time for users includes:

[0048] If the average power outage time for users of the distribution network is set to a target value, and the average power outage time for users of the distributed photovoltaic power grid does not exceed the target value, then the reliability of the distribution network is determined to be high reliability.

[0049] As can be seen from the above description, the shorter the average outage time for distributed photovoltaic power generation users, the higher the reliability of the power distribution network. By setting a target value, the reliability can be quickly assessed.

[0050] Furthermore, target values ​​for the average power outage time for distribution network users are set, including:

[0051] Set target values ​​for the average power outage time for users of the distribution network by region, and set corresponding target values ​​according to the grade category of the power supply area in which the distribution network region is located.

[0052] As described above, the target value for the average power outage time of distribution network users is set according to region. Different power supply areas have corresponding level categories and their target values, which can be adaptively adjusted according to different power supply areas during reliability assessment.

[0053] Furthermore, if the average power outage time for users in the distributed photovoltaic grid exceeds the target value, the distribution grid area is increased proportionally, and steps S1 to S4 are returned to the execution process based on the increased distribution grid area.

[0054] As described above, by increasing the scale of regional power distribution network development and integrating surrounding distributed photovoltaic power into the regional power distribution network, the power outage time of photovoltaic power can be reduced until the average power outage time of users taking into account the output of distributed photovoltaic power meets the requirements.

[0055] Please refer to Figure 2 Another embodiment of the present invention provides a reliability calculation terminal for a distributed photovoltaic (PV) grid, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the various steps of the above-described reliability calculation method for a distributed PV grid.

[0056] The reliability calculation method and terminal for a distribution network with distributed photovoltaic (PV) grid access described above are applicable to accurately evaluating the power supply reliability level after distributed PV grid access. The following detailed implementation methods illustrate this:

[0057] Example 1

[0058] Please refer to Figure 1 and Figure 3 A reliability calculation method for a distribution network with distributed photovoltaic (PV) grid integration, comprising the following steps:

[0059] S0. Collect the fault start time Ts and fault repair time Tr of the distribution network, and obtain the fault duration Tm of the distribution network, Tm = Tr - Ts.

[0060] S1. Calculate the duration of user power outages reduced by distributed photovoltaic power generation based on the obtained fault duration of the distribution network and the effective output time of distributed photovoltaic power generation.

[0061] S11. The total duration during which the output coefficient of distributed photovoltaic power generation is greater than a preset ratio within the fault duration of the distribution network shall be taken as the effective output time Tpv of distributed photovoltaic power generation.

[0062] Intermittency and volatility are inherent characteristics of distributed photovoltaic (PV) systems. This means that the output coefficient of a distributed PV system will fluctuate between 0% and 100% at any given moment. In this embodiment, the preset ratio is preferably 80%. During periods when the output coefficient is greater than this ratio, the output is considered stable and effective, and can support the operation of the entire power grid.

[0063] Therefore, the total duration during which the output coefficient of distributed photovoltaic (PV) is greater than a preset proportion within the fault duration of the distribution network is taken as the effective output time Tpv of distributed PV, so that Tpv can serve as a quantitative evaluation index to avoid the intermittency and volatility of distributed PV output.

[0064] S12. Calculate the user outage duration Tpvs reduced by distributed photovoltaic based on the fault duration Tm of the distribution network and the effective output time Tpv of the distributed photovoltaic system, where Tpvs = Tm - Tpv.

[0065] Therefore, the Tpvs calculation formula can be used to quantitatively calculate the reduction in power outage time for users caused by distributed photovoltaic power generation.

[0066] S2. Calculate the total capacity of the distribution network and the average capacity of the distribution network users. Based on the average capacity of the distribution network users and the load factor, calculate the equivalent number of power outage users reduced by distributed photovoltaic power generation.

[0067] Specifically, the total capacity of the distribution network is calculated, which is equal to the cumulative value of the capacity of all users. Dividing the cumulative value by the total number of users yields the average capacity of each user in the distribution network.

[0068] Among them, the load capacity ratio c is obtained by dividing the system power supply of the distribution network by the total system capacity and then by the first preset coefficient.

[0069] The equivalent number of power outage users u1 reduced by distributed photovoltaic power generation is calculated based on the average capacity a and the carrying capacity ratio c of the distribution network users: u1=p×V×I1 / c / a;

[0070] In the formula, p represents the second preset coefficient, V represents the nominal voltage, and I1 represents the fault current change value.

[0071] Specifically, in this embodiment, the load capacity ratio c of the previous year is calculated. At this time, the first preset coefficient is 8760, so c = system power supply / total system capacity / 8760.

[0072] In this embodiment, the second preset coefficient p is 1.732, and the equivalent number of power outage users u1 can be obtained as 1.732 × nominal voltage V × current change value I1 / previous year's load capacity ratio c / average capacity a of distribution network users.

[0073] S3. Calculate the power outage time for photovoltaic output reduction by combining the user outage duration of the distributed photovoltaic reduction and the equivalent number of outage users.

[0074] The product of the user power outage duration calculated for each power outage and the equivalent number of users experiencing power outages is accumulated.

[0075] Divide the cumulative calculation result by the total number of users in the distribution network to obtain the outage time due to the reduction in photovoltaic output.

[0076] S4. Obtain the outage time of the power distribution network, subtract the outage time caused by the reduction in photovoltaic output from the outage time of the outage time to obtain the average outage time of users in the distributed photovoltaic power distribution network, and determine the reliability of the power distribution network through the average outage time of users.

[0077] S41. Obtain the outage time and the number of actual outage users for each fault in the distribution network, accumulate the product of the outage time and the number of actual outage users for each fault, and divide the accumulated calculation result by the total number of users in the distribution network to obtain the fault outage time of the distribution network.

[0078] S42. Subtract the outage time due to photovoltaic power reduction from the outage time caused by faults in the distribution network to obtain the average outage time for users in the distribution network with distributed photovoltaic access.

[0079] S43. Set a target value for the average power outage time of users in the distribution network. If the average power outage time of users in the distribution network connected to the distributed photovoltaic system does not exceed the target value, the reliability of the distribution network is determined to be high reliability.

[0080] Specifically, target values ​​for the average power outage time of distribution network users are set according to regions, with corresponding target values ​​set based on the grade category of the power supply area in which the distribution network region is located. In this embodiment, the target value for the average power outage time of regional distribution network users can be classified into categories A+, A, B, C, and D according to industry standards, based on the power supply area in which the region is located, and the targets are set as 5 minutes, 52 minutes, 3 hours, 12 hours, and 24 hours respectively.

[0081] If the average power outage time for users in the distributed photovoltaic grid exceeds the target value, the grid area is increased proportionally, and steps S1 to S4 are returned to the grid based on the increased grid area.

[0082] Specifically, by increasing the scale of regional power distribution network development and integrating surrounding distributed photovoltaic power into the regional power distribution network, the power outage time of photovoltaic power generation can be reduced. Steps S1 to S4 are repeated until the average power outage time of users who take into account the output of distributed photovoltaic power is less than or equal to the corresponding target value.

[0083] Example 2

[0084] Please refer to Figure 2 A reliability calculation terminal 1 for a distributed photovoltaic (PV) grid includes a memory 2, a processor 3, and a computer program stored in the memory 2 and executable on the processor 3. When the processor 3 executes the computer program, it implements the various steps of the reliability calculation method for a distributed PV grid according to Embodiment 1.

[0085] In summary, this invention provides a reliability calculation method and terminal for distribution networks with distributed photovoltaic (PV) integration. It obtains the fault duration of the distribution network and, based on this and the effective output time of the distributed PV, calculates the user outage duration reduced by the distributed PV. Furthermore, it calculates the equivalent number of users experiencing outages due to the distributed PV based on the average capacity and load factor of the distribution network users. By calculating the outage time due to PV output reduction based on the calculated user outage duration and the equivalent number of users experiencing outages, this method quantifies the reduction in user outage time caused by distributed PV, thereby accurately evaluating the power supply reliability level of the distribution network after considering distributed PV integration. This provides theoretical support for the refined evaluation of power supply reliability and guides power supply companies in optimizing power grid construction plans.

[0086] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for calculating the reliability of a distribution network with distributed photovoltaic (PV) access, characterized in that, Including the following steps: S1. Calculate the duration of user power outages reduced by distributed photovoltaic power generation based on the obtained fault duration of the distribution network and the effective output time of distributed photovoltaic power generation. S2. Calculate the total capacity of the distribution network and the average capacity of the distribution network users. Calculate the equivalent number of power outage users reduced by distributed photovoltaic power based on the average capacity of the distribution network users and the load factor. S3. Calculate the power outage time for photovoltaic power output reduction by combining the user outage duration of the distributed photovoltaic power reduction and the equivalent number of outage users; S4. Obtain the fault outage time of the distribution network, subtract the outage time caused by the reduction in photovoltaic output from the fault outage time to obtain the average outage time of users in the distribution network with distributed photovoltaic access, and determine the reliability of the distribution network through the average outage time of users. Before step S1, the following are included: Collect the fault start time Ts and fault repair time Tr of the distribution network, and obtain the fault duration Tm of the distribution network, Tm = Tr - Ts; Step S1 includes: The total duration during which the output coefficient of distributed photovoltaic (PV) is greater than a preset proportion within the fault duration of the distribution network is taken as the effective output time Tpv of distributed PV. The duration of user power outages reduced by distributed photovoltaic power generation is calculated based on the fault duration Tm of the distribution network and the effective output time Tpv of the distributed photovoltaic power generation, where Tpvs = Tm - Tpv. The equivalent number of users experiencing power outages due to distributed photovoltaic (PV) power reduction is calculated based on the average capacity and load factor of the distribution network users, including: The load-capacity ratio c is obtained by dividing the system power supply of the distribution network by the total system capacity and then by the first preset coefficient. Calculate the equivalent number of power outages u1 caused by distributed photovoltaic power generation based on the average capacity 'a' and the carrying capacity ratio 'c' of the distribution network users: u1 = p × V × I1 / c / a; In the formula, p represents the second preset coefficient, V represents the nominal voltage, and I1 represents the fault current change value; Step S3 includes: The product of the user power outage duration calculated for each power outage and the equivalent number of users experiencing power outages; Divide the cumulative calculation result by the total number of users in the distribution network to obtain the power outage time due to the reduction in photovoltaic output. Obtain the fault outage time of the distribution network, including: Obtain the power outage time and the actual number of users affected by each fault in the power distribution network; The product of the power outage time and the actual number of users experiencing power outages for each fault; Divide the cumulative calculation result by the total number of users in the distribution network to obtain the fault outage time of the distribution network; Determining the reliability of the distribution network by the average power outage time for users includes: If the average power outage time for users of the distribution network is set to a target value, and the average power outage time for users of the distributed photovoltaic power grid does not exceed the target value, then the reliability of the distribution network is determined to be high reliability.

2. The reliability calculation method for a distribution network with distributed photovoltaic access according to claim 1, characterized in that, Set target values ​​for the average power outage time for users in the distribution network, including: Set target values ​​for the average power outage time for distribution network users by region, and set corresponding target values ​​based on the grade category of the power supply area where the distribution network region is located.

3. The reliability calculation method for a distribution network with distributed photovoltaic access according to claim 1, characterized in that, If the average power outage time for users in the distributed photovoltaic grid exceeds the target value, the grid area is increased proportionally, and the process returns to steps S1 to S4 based on the increased grid area.

4. A reliability calculation terminal for a distributed photovoltaic (PV) grid, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements each step of the reliability calculation method for a distributed photovoltaic grid as described in any one of claims 1 to 3.

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