A method and system for calculating the capacity of distributed photovoltaic access to an active distribution network

Abstract

The present invention belongs to the technical field of electric power system, and specifically relates to a method and system for calculating the access capacity of distributed photovoltaic in an active distribution network, comprising: when a fault occurs in the active distribution network, obtaining the short-circuit current flowing from the distributed photovoltaic to the distribution network bus; considering the auxiliary effect of the distributed photovoltaic, determining the quick-break current constant of the distribution network bus according to the obtained short-circuit current, and listing the boundary formula for the quick-break protection not to malfunction; according to the obtained boundary formula, determining the upper limit value and amplitude limit value of the short-circuit current flowing from the distributed photovoltaic to the distribution network bus, and calculating the accessible capacity of the distributed photovoltaic.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power systems, and in particular relates to a method and system for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As the capacity of distributed photovoltaics connected to distribution networks gradually increases, its impact on relay protection has always attracted the attention of relay protection practitioners. The impact of distributed photovoltaics on the three-stage overcurrent protection in distribution networks mainly includes auxiliary increase, external extraction and reverse.

[0004] A related study proposed a method for configuring relay protection for active distribution networks, and analyzed the impact of distributed photovoltaic access on protection, including that when the fault occurs downstream of the protection, the protection is exceeded due to the auxiliary effect of the photovoltaic power station providing short-circuit current; when the distributed photovoltaic power station is connected downstream of the protection, the protection sensitivity and protection range are reduced due to the shunting effect of photovoltaics; however, no further quantitative analysis was made on the specific impact of the protection. A related study proposed a study on the impact of distributed photovoltaic short-circuit characteristics on distribution network protection, and analyzed the different short-circuit fault characteristics of distributed photovoltaics, including single-phase short circuit, phase-to-phase short circuit, three-phase short circuit and other fault types. And the impact on the relay protection of the distribution network; analyzed the impact of the auxiliary and external pumping effects of distributed photovoltaics on the traditional three-stage overcurrent protection, and proposed improvement measures; however, only qualitative analysis was conducted, and no quantitative analysis of the impact was conducted. A related study proposed a study on relay protection for distributed photovoltaic access to distribution networks, introduced the principle and constant value setting method of the existing three-stage current protection in the distribution network, and analyzed the impact of distributed photovoltaic access on the existing protection in terms of action reliability and sensitivity; pointed out that distributed photovoltaic access reduces the sensitivity of upstream lines to faults, while increasing the probability of over-tripping and protection delays; and greatly improves the sensitivity of downstream lines to faults, but there is a high probability that the fault point will over-trip, thereby expanding the scope of the fault.

[0005] According to the inventors' understanding, in the prior art, theoretical analysis or simulation analysis has been conducted on the impact of the access of distributed photovoltaics on the existing three-stage current protection, and it has been pointed out that the distributed photovoltaics have an auxiliary and external absorption effect on the fault current, which affects the reliability and sensitivity of the protection; however, it is only a simple qualitative analysis, and there is no quantitative analysis of the specific impact of distributed photovoltaics on the existing current protection. Therefore, it is impossible to point out how many distributed photovoltaics can cause the protection to malfunction or refuse to operate, which makes it difficult to apply in actual engineering. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a method and system for calculating the access capacity of distributed photovoltaic in an active distribution network, which is triggered from the perspective of relay protection principle and overcurrent protection setting, combined with the auxiliary effect of distributed photovoltaic on the outgoing short-circuit current, to complete the analysis of the distributed photovoltaic capacity that can be connected in the distribution network.

[0007] According to some embodiments, a first solution of the present invention provides a method for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network, using the following technical solution:

[0008] A method for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network, comprising:

[0009] When an active distribution network fails, the short-circuit current flowing from distributed photovoltaics to the distribution network bus is obtained;

[0010] Considering the boosting effect of distributed photovoltaics, the quick-break current setting value of the distribution network bus is determined according to the obtained short-circuit current, and the boundary formula for the quick-break protection to avoid false operation is written;

[0011] According to the obtained boundary formula, the upper limit and amplitude limit of the short-circuit current flowing from distributed photovoltaic to the distribution network bus are determined, and the accessible capacity of distributed photovoltaic is calculated.

[0012] As a further technical limitation, the short-circuit current of the distributed photovoltaic to the distribution network busbar is obtained. for in, Z is the short-circuit current flowing into the busbar from the distributed photovoltaic outside the line; S is the busbar short-circuit impedance; Z L is the impedance of the distribution network bus.

[0013] Furthermore, when the distribution network bus outlet is short-circuited, the distributed photovoltaic short-circuit current outside the line will all flow into the fault point; when the distribution network bus terminal is short-circuited, most of the distributed photovoltaic short-circuit current outside the line will flow into the active distribution network.

[0014] As a further technical limitation, in order to prevent the access of photovoltaic power sources from exceeding the quick-break protection range, the quick-break current setting value of the distribution network bus must meet the following requirements: in, is the fast-break current setting value of the distribution network bus, that is, in, The value range is 1.3~1.5. is the system phase voltage; Z S is the busbar short-circuit impedance; Z L is the impedance of the distribution network bus.

[0015] As a further technical limit, the obtained quick-break current constant of the distribution network bus is simplified, and combined with the cosine theorem, a boundary formula is written to ensure that the quick-break protection does not malfunction, and the upper and lower limits and amplitude limit of the short-circuit current are determined.

[0016] Furthermore, the distributed photovoltaic grid-connected point under consideration is located at the busbar, and the access capacity boundary is the most conservative access capacity boundary, that is, when the access capacity is within the given range, there will be no over-tripping of the quick-break protection.

[0017] As a further technical limitation, the short-circuit current generated by distributed photovoltaics during short circuit is clarified, and then the distributed photovoltaic access capacity boundary is obtained based on the relationship between the short-circuit current and the rated current, and the accessible capacity of distributed photovoltaics is calculated.

[0018] According to some embodiments, a second solution of the present invention provides a distributed photovoltaic access capacity calculation system for an active power distribution network, which adopts the following technical solution:

[0019] A distributed photovoltaic access capacity calculation system for an active power distribution network, comprising:

[0020] An acquisition module, which is configured to acquire the short-circuit current flowing from the distributed photovoltaic to the distribution network bus when a fault occurs in the active distribution network;

[0021] The calculation module is configured to take into account the auxiliary effect of distributed photovoltaics, determine the quick-break current setting of the distribution network bus according to the obtained short-circuit current, and list the boundary formula for the quick-break protection to prevent false operation; based on the obtained boundary formula, determine the upper limit and amplitude limit of the short-circuit current of the distributed photovoltaics flowing to the distribution network bus, and calculate the accessible capacity of the distributed photovoltaics.

[0022] According to some embodiments, a third solution of the present invention provides a computer-readable storage medium, which adopts the following technical solution:

[0023] A computer-readable storage medium stores a program, which, when executed by a processor, implements the steps in calculating the distributed photovoltaic access capacity of an active power distribution network as described in the first solution of the present invention.

[0024] According to some embodiments, a fourth solution of the present invention provides an electronic device, which adopts the following technical solution:

[0025] An electronic device comprises a memory, a processor and a program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in calculating the distributed photovoltaic access capacity of an active power distribution network as described in the first solution of the present invention are implemented.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention is based on the boosting effect of distributed photovoltaics on the current flowing through the protection installation, considers the principle of three-stage current protection and the constant value setting method, analyzes the impact of distributed photovoltaics on the three-stage current protection in the distribution network; and derives the access capacity of distributed photovoltaics that the existing protection in the distribution network can adapt to. The boosting effect considered in the present invention is the impact of distributed photovoltaics outside the line on the protection of this line, and the analysis result is the limit value of the distributed photovoltaic capacity that can be connected outside this line; the principle of the boosting effect on the protection of this line is to cause the current of this line to increase, considering preventing the protection from exceeding the protection range and causing false operation.

[0028] The present invention starts from the auxiliary effect of distributed photovoltaic short-circuit current on the short-circuit current at the outgoing line switch, considers the principle of relay protection and the three-stage current protection constant setting method, and derives a calculation method for the boundary of the accessible capacity of distributed photovoltaic in the active distribution network, which can ensure that the accessible capacity adapts to the existing protection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings in the specification that constitute a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments of this embodiment and their descriptions are used to explain this embodiment and do not constitute improper limitations on this embodiment.

[0030] Figure 1 This is a flow chart of a method for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network in Embodiment 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of an active power distribution network in Embodiment 1 of the present invention;

[0032] Figure 3 This is a schematic diagram of short-circuit current analysis in Embodiment 1 of the present invention;

[0033] Figure 4 This is a schematic diagram of the angle relationship when the photovoltaic power generation only generates reactive power in the first embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the angle relationship when the photovoltaic power only generates active power in the first embodiment of the present invention;

[0035] Figure 6 Schematic diagram of the relationship between the short-circuit current of the photovoltaic device that can be connected and θ in the first embodiment of the present invention;

[0036] Figure 7 Schematic diagram of the topological structure of the simulation system without photovoltaic access in the first embodiment of the present invention;

[0037] Figure 8 Schematic diagram of voltage and current simulation waveforms when there is no photovoltaic access in the first embodiment of the present invention;

[0038] Fig. 9A schematic diagram of the topological structure of a photovoltaic access simulation system in Embodiment 1 of the present invention;

[0039] Fig.10 It is a schematic diagram of simulation waveforms of a photovoltaic access simulation model in the first embodiment of the present invention;

[0040] Fig.11 This is a structural block diagram of a system for calculating the capacity of distributed photovoltaic access to an active distribution network in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] Embodiment 1

[0046] The embodiment of the present invention introduces a method for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network.

[0047] like Figure 1 A method for calculating the capacity of distributed photovoltaic access to an active distribution network is shown, comprising:

[0048] When an active distribution network fails, the short-circuit current flowing from distributed photovoltaics to the distribution network bus is obtained;

[0049] Considering the boosting effect of distributed photovoltaics, the quick-break current setting value of the distribution network bus is determined according to the obtained short-circuit current, and the boundary formula for the quick-break protection to avoid false operation is written;

[0050] According to the obtained boundary formula, the upper limit and amplitude limit of the short-circuit current flowing from distributed photovoltaic to the distribution network bus are determined, and the accessible capacity of distributed photovoltaic is calculated.

[0051] like Figure 2In the active distribution network shown in the figure, when a short-circuit fault occurs on line 1, part of the short-circuit current of the distributed photovoltaic outside line 1 flows to the fault point, which helps to increase the current flowing through the line protection. Figure 3 , the short-circuit current of distributed photovoltaic flowing through protection 1 is As shown in formula (1):

[0052]

[0053] in, It is the short-circuit current of the distributed photovoltaic power plant outside the line flowing into the busbar, which is generally 1.05 to 1.3 times the rated current of the connected photovoltaic power plant; Z S is the busbar short-circuit impedance; Z L is the impedance of line 1.

[0054] It can be seen from formula (1) that when the line outlet is short-circuited, the short-circuit current of the distributed photovoltaic power generation outside the line will all flow into the fault point, which is conducive to the protection action. When the line end is short-circuited, most of the short-circuit current of the distributed photovoltaic power generation outside the line will flow into the system, which has almost no effect on the outgoing line short-circuit current.

[0055] The boosting effect of distributed photovoltaics is conducive to the overcurrent protection action and will not affect the sensitivity of the protection action. However, when there is a segmented circuit breaker on the outgoing line, the quick-break protection must avoid the fault at the installation point of the intermediate circuit breaker to prevent the quick-break protection from exceeding the protection range and malfunctioning. The requirement for quick-break protection is that when a three-phase short circuit occurs at the end of the line under the maximum operating mode, the fault current must be less than the protection setting value.

[0056] In order to prevent the photovoltaic power supply from exceeding the quick-break protection range, the following formula must be satisfied:

[0057]

[0058] in, is the quick-break current setting value of protection 1, and its calculation formula is shown in formula (3). The value range is 1.3~1.5. is the system phase voltage;

[0059]

[0060] From (1)(2)(3) we can get

[0061]

[0062] After simplification, we can get

[0063]

[0064] Due to the differences in system operation mode, line parameters, and photovoltaic power factor during short circuit, the following equation (5) and The change in phase difference, is θ.

[0065] According to the cosine theorem, equation (5) can be written as:

[0066]

[0067] Simplified, we can get

[0068]

[0069] From (7), we can get

[0070]

[0071] Let the system voltage The reference angle is 0, assuming that the photovoltaic power generation is only reactive during the short circuit fault, and the system equivalent impedance is set to a fixed value of 75 degrees. Figure 4 As shown, the angle It is 15 degrees.

[0072] During a short-circuit fault, when the photovoltaic power generation is only active, Figure 5 As shown, the angle It is -75 degrees.

[0073] When the active and reactive power generated by photovoltaic power during a short circuit fault is between the above two situations, Between -75 degrees and 15 degrees.

[0074] According to formula (9), we can draw The mapping relationship with θ is as follows Figure 6 As shown. When θ changes from -75 degrees to 15 degrees, It decreases first and then increases, and the minimum value can be obtained at 0 degrees.

[0075] In order to verify the correctness of formula (9), a simulation model was built on the PSCAD simulation platform to simulate and verify the formula. First, a simulation model without photovoltaic access was built using a 10 kV substation as a typical scenario. The topology structure is as follows: Figure 7 As shown. The equivalent impedance of the 10 kV system in the model is 1.0376 ohms, and the impedance angle is 75 degrees. The length of the transmission line is 1.7 km, and the line model selects the Pi type parameter model. When a three-phase short circuit fault occurs at the end, the short circuit current is 3.811 kA, and the reliability coefficient of the current quick-break protection is If 1.3 is taken, the current quick-break protection setting is 4.955 kA. The simulation model parameters and simulation results without photovoltaic access are shown in Table 1. Figure 8 Shown are the short-circuit voltage and short-circuit current at the outlet.

[0076] Table 1 Model parameters when there is no photovoltaic access

[0077]

[0078] The topology diagram of the simulation system including photovoltaic access is as follows: Fig. 9 As shown, when the photovoltaic access capacity reaches 42.96MW, the line short-circuit current is 4.955, reaching the protection action boundary. The simulation waveform is as follows Fig.10 As shown, U_bus is the bus voltage, Ipv_sum is the photovoltaic short-circuit current, and I_L1 is the outgoing line short-circuit current.

[0079] Table 2 Simulation results when the PV capacity is at the access capacity boundary

[0080]

[0081] As shown in Table 2, is 13.14 degrees, and substituting it into formula (9) yields I pv <2.655kA, and the error with the simulation result of 2.783 is 4.6%. It can be seen that formula (9) has a high accuracy.

[0082] This embodiment is based on the boosting effect of distributed photovoltaics on the current flowing through the protection installation, takes into account the principle and constant value setting method of three-stage current protection, analyzes the impact of distributed photovoltaics on the three-stage current protection in the distribution network; and derives the access capacity of distributed photovoltaics that can be adapted to the existing protection in the distribution network. The boosting effect considered in the present invention is the impact of distributed photovoltaics outside the line on the protection of this line, and the analysis result is the limit of the distributed photovoltaic capacity that can be accessed outside this line; the principle of the boosting effect on the protection of this line is to cause the current of this line to increase, and consider preventing the protection from exceeding the protection range and causing false operation; starting from the boosting effect of distributed photovoltaic short-circuit current on the short-circuit current at the outgoing line switch, considering the principle of relay protection and the three-stage current protection constant value setting method, the calculation method of the boundary of the capacity that can be accessed by distributed photovoltaics in the active distribution network is derived, which can ensure that the access capacity adapts to the existing protection method.

[0083] Embodiment 2

[0084] Embodiment 2 of the present invention introduces a system for calculating the capacity of distributed photovoltaic access to an active power distribution network.

[0085] like Fig.11 The system for calculating the capacity of distributed photovoltaic access to an active power distribution network shown in the figure comprises:

[0086] An acquisition module, which is configured to acquire the short-circuit current flowing from the distributed photovoltaic to the distribution network bus when a fault occurs in the active distribution network;

[0087] The calculation module is configured to take into account the auxiliary effect of distributed photovoltaics, determine the quick-break current setting of the distribution network bus according to the obtained short-circuit current, and list the boundary formula for the quick-break protection to prevent false operation; based on the obtained boundary formula, determine the upper limit and amplitude limit of the short-circuit current of the distributed photovoltaics flowing to the distribution network bus, and calculate the accessible capacity of the distributed photovoltaics.

[0088] The detailed steps are the same as the method for calculating the distributed photovoltaic access capacity of the active distribution network provided in Example 1, and will not be repeated here.

[0089] Embodiment 3

[0090] Embodiment 3 of the present invention provides a computer-readable storage medium.

[0091] A computer-readable storage medium stores a program, which, when executed by a processor, implements the steps in the method for calculating the capacity of distributed photovoltaic access to an active distribution network as described in the first embodiment of the present invention.

[0092] The detailed steps are the same as the method for calculating the distributed photovoltaic access capacity of the active distribution network provided in Example 1, and will not be repeated here.

[0093] Embodiment 4

[0094] A fourth embodiment of the present invention provides an electronic device.

[0095] An electronic device comprises a memory, a processor and a program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the method for calculating the access capacity of distributed photovoltaic power generation in an active power distribution network as described in the first embodiment of the present invention are implemented.

[0096] The detailed steps are the same as the method for calculating the distributed photovoltaic access capacity of the active distribution network provided in Example 1, and will not be repeated here.

[0097] The above description is only a preferred embodiment of the present embodiment and is not intended to limit the present embodiment. For those skilled in the art, the present embodiment may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present embodiment shall be included in the protection scope of the present embodiment.

Claims

1. A method for calculating the capacity of distributed photovoltaic access to an active distribution network, characterized in that: include: When an active distribution network fails, the short-circuit current flowing from distributed photovoltaics to the distribution network bus is obtained; Considering the boosting effect of distributed photovoltaics, the quick-break current setting value of the distribution network bus is determined according to the obtained short-circuit current, and the boundary formula for the quick-break protection to avoid false operation is written; According to the obtained boundary formula, the upper limit and amplitude limit of the short-circuit current flowing from the distributed photovoltaic to the distribution network bus are determined, and the accessible capacity of the distributed photovoltaic is calculated; The formula satisfied by the fast-break current setting value of the distribution network bus, the short-circuit current formula of the distributed photovoltaic to the distribution network bus, and the fast-break current setting value formula of the distribution network bus are obtained: in is the system phase voltage, is the busbar short-circuit impedance; is the line impedance between the fault point and the busbar, The value range is 1.3~1.

5. It is the short-circuit current flowing into the busbar from the distributed photovoltaic outside the line; After simplification, we get: Due to differences in system operation mode, line parameters, and photovoltaic power factor during short circuit, the above formula and The change of phase difference, let < , > is θ; According to the law of cosines, the above formula can be written as: Simplified, we can get From the above formula, we get Let the system voltage The reference angle is 0. Assuming that the photovoltaic power generation is only reactive during the short-circuit fault, the system equivalent impedance is set to 75 degrees. 15 degrees; When the photovoltaic power only generates active power during a short circuit fault, the angle is -75 degrees; During a short-circuit fault, the active and reactive power generated by photovoltaic power generation is between the above two situations. Between -75 degrees and 15 degrees; When the temperature changes from -75 degrees to 15 degrees, It decreases first, then increases, and reaches the minimum value at 0 degrees.

2. A method for calculating the capacity of distributed photovoltaic access to an active distribution network as claimed in claim 1, characterized in that: The short-circuit current from distributed photovoltaic to the distribution network busbar for ;in, It is the short-circuit current flowing into the busbar from the distributed photovoltaic outside the line; is the busbar short-circuit impedance; is the impedance of the distribution network bus.

3. A method for calculating the distributed photovoltaic access capacity of an active distribution network as claimed in claim 2, characterized in that: When the distribution network bus outlet is short-circuited, the distributed photovoltaic short-circuit current outside the line will all flow into the fault point; when the distribution network bus terminal is short-circuited, most of the distributed photovoltaic short-circuit current outside the line will flow into the active distribution network.

4. A method for calculating the distributed photovoltaic access capacity of an active power distribution network as claimed in claim 1, characterized in that: In order to prevent the quick-break protection range from being exceeded due to the access of photovoltaic power sources, the quick-break current setting value of the distribution network bus must meet the following requirements: ;in, is the fast-break current setting value of the distribution network bus, that is, ,in, The value range is 1.3~1.

5. is the system phase voltage; is the busbar short-circuit impedance; is the line impedance between the fault point and the busbar.

5. A method for calculating the distributed photovoltaic access capacity of an active power distribution network as claimed in claim 1, characterized in that: The obtained fast-trip current constant of the distribution network bus is simplified, and combined with the cosine theorem, the boundary formula for the fast-trip protection to prevent false operation is listed to determine the upper and lower limits and amplitude limit of the short-circuit current.

6. A method for calculating the distributed photovoltaic access capacity of an active power distribution network as claimed in claim 5, characterized in that: The distributed photovoltaic grid-connected point under consideration is located at the busbar, and the access capacity boundary is the most conservative access capacity boundary, that is, when the access capacity is within the given range, there will be no over-tripping of the quick-break protection.

7. A method for calculating the distributed photovoltaic access capacity of an active power distribution network as claimed in claim 1, characterized in that: Clarify the short-circuit current generated by distributed photovoltaics during short circuit, and then obtain the distributed photovoltaic access capacity boundary based on the relationship between the short-circuit current and the rated current, and calculate the accessible capacity of distributed photovoltaics.

8. A distributed photovoltaic access capacity calculation system for an active distribution network, characterized in that: include An acquisition module, which is configured to acquire the short-circuit current flowing from the distributed photovoltaic to the distribution network bus when a fault occurs in the active distribution network; The calculation module is configured to consider the auxiliary effect of distributed photovoltaics, determine the quick-break current setting value of the distribution network bus according to the obtained short-circuit current, and list the boundary formula for the quick-break protection to prevent false operation; according to the obtained boundary formula, determine the upper limit and amplitude limit of the short-circuit current flowing from distributed photovoltaics to the distribution network bus, and calculate the accessible capacity of distributed photovoltaics. The formula satisfied by the fast-break current setting value of the distribution network bus, the short-circuit current formula of the distributed photovoltaic to the distribution network bus, and the fast-break current setting value formula of the distribution network bus are obtained: in is the system phase voltage, is the busbar short-circuit impedance; is the line impedance between the fault point and the busbar, The value range is 1.3~1.

5. It is the short-circuit current flowing into the busbar from the distributed photovoltaic outside the line; After simplification, we get: Due to differences in system operation mode, line parameters, and photovoltaic power factor during short circuit, the above formula and The change of phase difference, let < , > is θ; According to the law of cosines, the above formula can be written as: Simplified, we can get From the above formula, we get Let the system voltage The reference angle is 0. Assuming that the photovoltaic power generation is only reactive during the short-circuit fault, the system equivalent impedance is set to 75 degrees. 15 degrees; When the photovoltaic power only generates active power during a short circuit fault, the angle is -75 degrees; During a short-circuit fault, the active and reactive power generated by photovoltaic power generation is between the above two situations. Between -75 degrees and 15 degrees; When the temperature changes from -75 degrees to 15 degrees, It decreases first, then increases, and reaches the minimum value at 0 degrees.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for calculating the distributed photovoltaic access capacity of an active distribution network as described in any one of claims 1 to 7 are implemented.

10. An electronic device 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 program, the steps of the method for calculating the distributed photovoltaic access capacity of the active distribution network as described in any one of claims 1 to 7 are implemented.

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