Assessment method and device for quantitatively analyzing influence of distributed power supply access on distribution line outlet protection

Abstract

The invention discloses an evaluation method and device for quantitatively analyzing the influence of distributed power supply access on distribution line outlet protection, and the method comprises the steps: calculating the protection sensitivity of a distribution line outlet when a distributed power supply is not accessed and the permeability of the accessed distributed power supply, and calculating the protection sensitivity of the distribution line outlet based on the calculated permeability and protection sensitivity; calculating the protection sensitivity of the outlet of the distribution line after the distributed power supply is accessed; based on the influence of the protection sensitivity after the access of the distributed power supply on the outlet protection of the distribution line, the evaluation results comprise no influence, general influence on the outlet protection of the distribution line, need of adjustment of a protection constant value, serious influence and need of replacement of protection configuration. According to the method, the permeability of the distributed power supply is taken as an independent variable, the access position of the distributed power supply is considered, the adaptability of distribution line outlet protection is quantitatively analyzed, the influence degree of the protection is quantitatively evaluated, and support is provided for protection constant value adjustment and configuration change.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical engineering relay protection, and specifically relates to an evaluation method and device for quantitatively analyzing the impact of distributed power supply access on distribution line outlet protection. Background Art

[0002] After the distributed power generation is connected to the distribution network, the amplitude and distribution pattern of the short-circuit current have changed, causing the original distribution line outlet protection configuration scheme to fail to operate or malfunction, expanding the scope of the fault impact, increasing economic losses, and reducing power supply reliability.

[0003] To solve the above problems from the aspect of relay protection, it is necessary to evaluate the impact of distributed power generation on protection after access and analyze the adaptability of protection. One way is to update the protection system of the active distribution network. Redesigning, configuring, and replacing equipment is the fundamental way to solve the above problems, but this requires a lot of time, technology, and economic costs. Another way is to make full use of protection devices (PDs) and appropriately adjust the setting or coordination relationship so that the existing relay protection can still operate accurately and reliably in the active distribution network. This method avoids the time and economic loss caused by replacing protection equipment. Therefore, it is necessary to evaluate the impact of distributed power generation on the original current protection after access to the distribution network in order to select a suitable solution.

[0004] At present, there have been some qualitative studies on the impact of distributed generation on the original current protection after it is connected to the distribution network, but there is still a lack of quantitative research on the impact of distributed generation on the relay protection of the distribution network to provide a reference for the configuration, setting and adjustment of the distribution network line outlet protection. Summary of the invention

[0005] The purpose of the present invention is to provide an evaluation method and device for quantitatively analyzing the impact of distributed power access on the protection of distribution line outlets, so as to quantify the degree of influence of distributed power on the protection of distribution network line outlets. The present invention takes the distributed power penetration rate as an independent variable, considers the access location of the distributed power source, quantitatively analyzes the adaptability of the protection of the distribution line outlet, and quantitatively evaluates the degree of influence of the protection, providing support for the fixed value adjustment and configuration change of the protection.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an evaluation method for quantitatively analyzing the impact of distributed power generation access on distribution line outlet protection, comprising:

[0008] Calculate the protection sensitivity of the distribution line outlet when the distributed power source is not connected;

[0009] Calculate the penetration rate of the connected distributed power source, and based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculate the protection sensitivity of the distribution line outlet after the distributed power source is connected;

[0010] Based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, the impact of the distribution line outlet protection is evaluated, and the evaluation results include: there is no impact on the distribution line outlet protection after the distributed power source is connected, there is a general impact on the distribution line outlet protection after the distributed power source is connected, and the protection setting needs to be adjusted; and there is a serious impact on the distribution line outlet protection after the distributed power source is connected, and the protection configuration needs to be replaced.

[0011] Preferably, the calculation of the protection sensitivity of the distribution line outlet when the distributed power source is not connected includes:

[0012] ,

[0013] in, is the protection sensitivity of the current section III at the distribution line outlet circuit breaker, It is the short-circuit current value under the minimum operation mode of the system when a two-phase short-circuit fault occurs at the end of the distribution line. is the protection setting value of current section III, is the reliability factor of current stage III protection, is the self-starting coefficient of the motor, is the return coefficient of the current relay, is the maximum load current of the distribution line.

[0014] Preferably, the calculating the penetration rate of the connected distributed power sources includes:

[0015] ,

[0016] in, is the penetration rate of connected distributed generation, is the total output of distributed generation in the distribution network, is the total power of the load.

[0017] Preferably, based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculating the protection sensitivity of the distribution line outlet after the distributed power source is connected includes:

[0018] Based on the penetration rate of the distributed power source, the short-circuit current flowing through the outlet protection of the distribution line after the distributed power source is connected is determined as follows:

[0019] ,

[0020] in, It is the short-circuit current flowing through the outlet protection of the distribution line after the distributed power source is connected. is the percentage of the distributed generation access location to the total length of the line, Indicates the short-circuit current provided by the distributed generation;

[0021] The protection sensitivity of the distribution line outlet after the distributed power source is connected is calculated based on the short-circuit current flowing through the distribution line outlet protection after the distributed power source is connected, as follows:

[0022] ,

[0023] in, It is the protection sensitivity of the distribution line outlet after the distributed power source is connected.

[0024] Preferably, the impact of distribution line outlet protection is evaluated based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, including:

[0025] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is greater than or equal to the preset value, it is determined that there is no impact on the protection;

[0026] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is less than the preset value, the protection setting value of the current segment III is adjusted, and the protection sensitivity after the protection setting value adjustment is recalculated;

[0027] If the protection sensitivity after the protection setting value is adjusted is greater than or equal to the preset value, it is judged as a general impact and can be used normally after the adjusted protection setting value is adopted;

[0028] If the protection sensitivity after the protection setting is adjusted is less than the preset value, it is judged as a serious impact and the protection configuration needs to be replaced.

[0029] Preferably, the preset value is 1.5.

[0030] Preferably,

[0031] The adjustment of the protection setting value of the current section III includes:

[0032] Assume that the current III protection setting is times the maximum load current of the distribution line, within the following range Make adjustments and get the adjusted value ,Will Times the maximum load current of the distribution line is used as the adjusted current III protection setting value.

[0033] .

[0034] Preferably, the recalculating the protection sensitivity after the protection setting value is adjusted includes:

[0035] ;

[0036] in, It is the protection sensitivity after the protection setting is adjusted. It is the protection setting value of the adjusted current section III.

[0037] In a second aspect, the present invention provides an evaluation device for quantitatively analyzing the impact of distributed power access on distribution line outlet protection, which is used to implement the above-mentioned evaluation method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection, and the device includes:

[0038] The first calculation module is used to calculate the protection sensitivity of the distribution line outlet when the distributed power source is not connected;

[0039] A second calculation module is used to calculate the penetration rate of the connected distributed power source, and based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculate the protection sensitivity of the distribution line outlet after the distributed power source is connected;

[0040] An evaluation module is used to evaluate the impact of distribution line outlet protection on distribution line outlet protection based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, and the evaluation results include: no impact on the distribution line outlet protection after the distributed power source is connected, a general impact on the distribution line outlet protection after the distributed power source is connected, and the protection setting needs to be adjusted; and a serious impact on the distribution line outlet protection after the distributed power source is connected, and the protection configuration needs to be replaced.

[0041] Preferably, the evaluation module is specifically used for:

[0042] The impact of distribution line outlet protection is assessed as follows:

[0043] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is greater than or equal to the preset value, it is determined that there is no impact on the protection;

[0044] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is less than the preset value, the protection setting value of the current segment III is adjusted, and the protection sensitivity after the protection setting value adjustment is recalculated;

[0045] If the protection sensitivity after the protection setting value is adjusted is greater than or equal to the preset value, it is judged as a general impact and can be used normally after the adjusted protection setting value is adopted;

[0046] If the protection sensitivity after the protection setting is adjusted is less than the preset value, it is judged as a serious impact and the protection configuration needs to be replaced;

[0047] The protection setting value of the current segment III is adjusted as follows:

[0048] Assume that the current III protection setting is times the maximum load current of the distribution line, within the following range Make adjustments and get the adjusted value ,Will Times the maximum load current of the distribution line is used as the adjusted current III protection setting value.

[0049] .

[0050] In a third aspect, the present invention provides a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform any of the methods described above.

[0051] In a fourth aspect, the present invention provides a computing device comprising one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the methods described above.

[0052] The present invention has the following beneficial effects:

[0053] 1. The present invention takes the penetration rate of distributed power sources as the independent variable, considers the access location of distributed power sources, quantitatively analyzes the adaptability of distribution line outlet protection, and quantitatively evaluates the impact of protection, providing support for the fixed value adjustment and configuration change of protection.

[0054] 2. The evaluation calculation process of the present invention is simple and can be completed by manual calculation. It has low requirements on the software and hardware of the protection device and fast calculation speed. In addition, the present invention takes extreme situations into consideration and meets the reliability requirements.

[0055] 3. The present invention can calculate the access capacity value of the distributed power source that protects the adaptation boundary, and provide support for the access of the distributed power source. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A flow chart of an evaluation method for quantitatively analyzing the impact of distributed power generation access on distribution line outlet protection provided by an embodiment of the present invention;

[0057] Figure 2 This is the power distribution line structure provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0059] It should be emphasized here that the step marks mentioned below are not intended to limit the order of the steps, but it should be understood that the steps can be executed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be executed simultaneously.

[0060] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0061] The specific embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0062] The present invention aims to provide an evaluation method for the impact of distribution line outlet protection, so as to quantify the impact of distributed power generation on the outlet protection of distribution network lines, which is divided into no impact, general impact and severe impact:

[0063] (1) No impact

[0064] Refers to the short-circuit current provided by the distributed power supply, which has no impact on the protection performance.

[0065] (2) General impact

[0066] It refers to the short-circuit current provided by distributed power sources, which affects the performance of protection. However, this impact can be solved by adjusting the configuration and setting of existing protection to solve problems such as protection refusal to operate, false operation and coordination problems.

[0067] (3) Serious impact

[0068] It means that the short-circuit current provided by the distributed power supply is large, which has a serious impact on the protection performance, causing the protection to refuse to operate and (or) malfunction, and it cannot be solved by adjusting the set value of the existing protection. A new protection device must be installed.

[0069] Distribution lines are usually equipped with staged current protection at the outlet circuit breaker. For the main line of the distribution network, the maximum coverage of the line outlet circuit breaker is determined by the current segment III protection. It is usually required that the current segment III can protect the entire length of the line and have a certain sensitivity when a fault occurs at the end of the line. The present invention takes the distributed power supply penetration rate as an independent variable, considers the access location of the distributed power supply, quantitatively analyzes the adaptability of the distribution line outlet protection, and quantitatively evaluates the impact of the protection, providing support for the fixed value adjustment and configuration change of the protection.

[0070] Example 1

[0071] This embodiment 1 provides an evaluation method for quantitatively analyzing the impact of distributed power generation access on distribution line outlet protection, see Figure 1 , the specific process is as follows:

[0072] Step 1: Determine the sensitivity of the line outlet protection when the distributed power source is not connected, and calculate according to formula (1):

[0073] (1)

[0074] in, The protection sensitivity of the current section III at the distribution line outlet circuit breaker is generally required to be , is the short-circuit current value of the system under the minimum operation mode when a two-phase short-circuit fault occurs at the end of the line, It is the protection setting value of the export current stage III. is the reliability coefficient of current stage III protection, generally 1.15~1.25, The self-starting coefficient of the motor is the ratio of the maximum current of the motor when it starts to the maximum load current during operation. The value is greater than 1 and should be determined by the specific network wiring and load properties. The value range is generally 1.5~3. is the return coefficient of the current relay, generally 0.85~0.95, is the maximum load current of the line.

[0075] Step 2: Determine the penetration rate of connected distributed generation according to formula (2) ,

[0076] (2)

[0077] Where: is the total output of distributed generation in the distribution network; is the total power of the load.

[0078] Step 3: Based on the penetration rate , determine the access penetration rate After the distributed power supply, the short-circuit current flowing through the outlet protection is as shown in formula (3).

[0079] To calculate the impact of distributed power on the short-circuit current of the outlet protection, the worst case is usually taken, that is, the maximum distributed power current and the minimum short-circuit current at the outlet. The terminal three-phase short-circuit current value at this time is:

[0080] (3)

[0081] In the formula, In order to consider the worst case terminal three-phase short-circuit current value after the distributed power supply is connected, , the percentage of the distributed generation access location in the total length of the line, It is the access location of distributed power source. is the total length of the distribution line, It represents the short-circuit current provided by the distributed generation, in kA.

[0082] Step 4: According to formula (4), determine the access penetration rate The sensitivity of the original current III protection after the distributed power supply,

[0083] (4)

[0084] if If it is greater than or equal to 1.5, there is no need to adjust the protection setting value, and it has no effect on the protection, and go to step 7; if If it is less than 1.5, go to step 5.

[0085] Step 5: If the sensitivity of the original current III protection Less than 1.5, assuming the original current III protection setting is times the load current, , then adjust the protection setting value according to formula (5), assuming that the protection setting value after the distributed power supply is connected is times the load current, the adjusted output current III protection setting is , according to the adjusted protection setting The protection sensitivity of current segment III is calculated using formula (6):

[0086] (5)

[0087] (6)

[0088] In the formula, is the protection setting value of the adjusted current segment III, It is the protection sensitivity of current section III after the protection setting is adjusted.

[0089] For distributed generation penetration The current stage III protection of the distribution network, that is, if the penetration rate of distributed generation is determined, then by adjusting the set value so that the sensitivity can meet the requirements, then The adjustable range is:

[0090] ;

[0091] If the protection sensitivity after adjustment If it is greater than or equal to 1.5, it is determined to be a general impact, and the protection setting can be adjusted for normal use and go to step 7; otherwise, go to step 6.

[0092] Step 6: If you adjust the protection sensitivity If it is less than 1.5, it is determined to be a serious impact and the protection configuration needs to be replaced.

[0093] Step 7: The program ends.

[0094] In practice, if you want to determine the capacity boundary of the connected distributed generation without replacing the protection, you can determine it according to formula (8):

[0095] (8)

[0096] Example 2

[0097] Using the evaluation method of Example 1 above, Figure 2 Taking the distribution line shown in FIG. 1 as an example, this embodiment 2 performs an impact assessment on the protection of the distribution line outlet, and the specific process is as follows:

[0098] like Figure 2 As shown, the capacity of the 110 / 10kV main transformer is 40MVA, the short-circuit voltage percentage is 15.5%, the main transformer adopts the method of ungrounded neutral point, and the rated current of the transformer is 2.3kA; the maximum short-circuit current on the 10kV side is 14.8kA. The length of the overhead distribution line is 6km, the impedance per unit length is Z=(0.17+0.33j)Ω / km, the impedance amplitude per kilometer is 0.36Ω, and the impedance angle is 62.5°. The maximum load capacity of the line is 10MW, and the maximum load current is 577A. , The maximum three-phase short-circuit current at the end of the line is 1.6kA. Table 1 lists the action value and action time of the export protection. The reliability coefficient of the line export current protection section III is taken as 1.25, the motor self-starting coefficient is taken as 1.5, and the return coefficient of the current relay is taken as 0.85. The protection setting value of the current section III is set to 1.273kA, and the action time is 0.5s.

[0099] Table 1 Configuration and setting scheme of staged current protection at line outlet

[0100]

[0101] (1) Sensitivity verification of existing protection

[0102] A two-phase short-circuit fault is set at the end of the line. When the fault occurs, the current section III protects the entire length of the line and has a certain sensitivity.

[0103] Table 2 Fault current and protection sensitivity of distribution lines

[0104]

[0105] (2) Calculation of the capacity boundary of accessible DER and short-circuit current value

[0106] The main factors affecting the accessible capacity of distributed generation are the sensitivity coefficient of the original protection, the self-starting coefficient of the motor and the access location of the distributed generation. Therefore, the accessible capacity of distributed generation without adjusting the protection setting can be calculated.

[0107] Table 3 DER access capacity and sensitivity

[0108]

[0109] It can be observed from the data in Table 3 that the sensitivity of the protection is limited to above 1.5, but the capacity of the distributed power source that can be connected is small and the penetration rate of the line is low. For lines that need to connect more distributed power sources, the protection parameters after connecting to the distributed power source are adjusted to 1.816 times the maximum load current, and the maximum connectable capacity of DER is preliminarily calculated.

[0110] Table 4 Protection sensitivity of adjusting protection setting value

[0111]

[0112] As can be seen from Table 4, the accessible capacity under the protection constraint usually meets the requirements of other constraints. The farther the DER is connected, the smaller the accessible capacity is. For the next simulation verification, only the distributed generation capacity allowed by the protection constraint and other constraints is connected at 20%, 40%, 60%, and 80% of the line to verify the protection sensitivity after the distributed generation is connected.

[0113] Table 5 Sensitivity of distributed generation after connection that meets the constraints

[0114]

[0115] From the data in Table 5, it can be seen that with the access of distributed power sources, the minimum short-circuit current at the end of the line will decrease, and the sensitivity of the protection will also decrease. After the 6MW distributed power source is connected to the 1.2km of the line, the sensitivity of the protection drops below 1.5, and the protection setting needs to be adjusted. The minimum short-circuit current at the end of the line is higher than the calculated value, which means that the actual circuit is affected by other factors, which weakens the drain effect of the distributed power source on the line outlet current, making the original constraint conditions fully applicable.

[0116] (3) Adjustment of protection setting and sensitivity verification

[0117] For the protection setting after connecting to the distributed power source, according to the above analysis The value was adjusted and the protection sensitivity was verified again after adjustment. After adjustment, the sensitivity was met, as shown in Table 5.

[0118] When connecting distributed power sources to the distribution network, it is necessary to consider whether the existing protection can work properly after the connected distributed power sources. Since the protection parameters are flexible and adjustable, the impact caused by the connection of distributed power sources can be reduced by adjusting the protection parameters, which can reduce the maintenance cost of relay protection that needs to be invested in the distribution network after the distributed power sources are connected, providing a convenient way to protect the active distribution network.

[0119] Example 3

[0120] Based on the same inventive concept, this embodiment 3 provides an evaluation device for quantitatively analyzing the impact of distributed power access on the protection of distribution line outlets, which is used to implement the evaluation method for quantitatively analyzing the impact of distributed power access on the protection of distribution line outlets in the above embodiment 1. The device includes:

[0121] The first calculation module is used to calculate the protection sensitivity of the distribution line outlet when the distributed power source is not connected;

[0122] A second calculation module is used to calculate the penetration rate of the connected distributed power source, and based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculate the protection sensitivity of the distribution line outlet after the distributed power source is connected;

[0123] An evaluation module is used to evaluate the impact of distribution line outlet protection on distribution line outlet protection based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, and the evaluation results include: no impact on the distribution line outlet protection after the distributed power source is connected, a general impact on the distribution line outlet protection after the distributed power source is connected, and the protection setting needs to be adjusted; and a serious impact on the distribution line outlet protection after the distributed power source is connected, and the protection configuration needs to be replaced.

[0124] In one embodiment, the evaluation module is specifically configured to:

[0125] The impact of distribution line outlet protection is assessed as follows:

[0126] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is greater than or equal to the preset value, it is determined that there is no impact on the protection;

[0127] If the protection sensitivity of the distribution line outlet after the distributed power source is connected is less than the preset value, the protection setting value of the current segment III is adjusted, and the protection sensitivity after the protection setting value adjustment is recalculated;

[0128] If the protection sensitivity after the protection setting value is adjusted is greater than or equal to the preset value, it is judged as a general impact and can be used normally after the adjusted protection setting value is adopted;

[0129] If the protection sensitivity after the protection setting is adjusted is less than the preset value, it is judged as a serious impact and the protection configuration needs to be replaced;

[0130] The protection setting value of the current segment III is adjusted as follows:

[0131] Assume that the current III protection setting is times the maximum load current of the distribution line, within the following range Make adjustments and get the adjusted value ,Will Times the maximum load current of the distribution line is used as the adjusted current III protection setting value.

[0132] .

[0133] It is worth pointing out that the device embodiment corresponds to the above-mentioned method embodiment, and the implementation methods of the above-mentioned method embodiments are all applicable to the device embodiment and can achieve the same or similar technical effects, so they will not be repeated here.

[0134] The present invention also provides a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by a computing device, the computing device executes the method of the above-mentioned embodiment 1.

[0135] The present invention also provides a computing device, comprising one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method according to the above-mentioned embodiment 1.

[0136] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt 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 codes.

[0137] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0138] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0139] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0140] 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 it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A quantitative analysis method for evaluating the impact of distributed power generation access on distribution line outlet protection, characterized in that: include: Calculate the protection sensitivity of the distribution line outlet when the distributed power source is not connected; Calculate the penetration rate of the connected distributed power source, and based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculate the protection sensitivity of the distribution line outlet after the distributed power source is connected; Based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, the impact of the distribution line outlet protection is evaluated, and the evaluation results include: there is no impact on the distribution line outlet protection after the distributed power source is connected, there is a general impact on the distribution line outlet protection after the distributed power source is connected, and the protection setting needs to be adjusted; and there is a serious impact on the distribution line outlet protection after the distributed power source is connected, and the protection configuration needs to be replaced.

2. According to claim 1, a method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection is characterized in that: The calculation of the protection sensitivity of the distribution line outlet when the distributed power source is not connected includes: ， in, is the protection sensitivity of the current section III at the distribution line outlet circuit breaker, It is the short-circuit current value under the minimum operation mode of the system when a two-phase short-circuit fault occurs at the end of the distribution line. is the protection setting value of current section III, is the reliability factor of current stage III protection, is the self-starting coefficient of the motor, is the return coefficient of the current relay, is the maximum load current of the distribution line.

3. According to claim 2, a method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection is characterized in that: The calculation of the penetration rate of the connected distributed power sources includes: ， in, is the penetration rate of connected distributed generation, is the total output of distributed generation in the distribution network, is the total power of the load.

4. According to claim 3, a method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection is characterized in that: Based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, the protection sensitivity of the distribution line outlet after the distributed power source is connected is calculated, including: Based on the penetration rate of the distributed power source, the short-circuit current flowing through the outlet protection of the distribution line after the distributed power source is connected is determined as follows: ， in, It is the short-circuit current flowing through the outlet protection of the distribution line after the distributed power source is connected. is the percentage of the distributed generation access location to the total length of the line, Indicates the short-circuit current provided by the distributed generation; The protection sensitivity of the distribution line outlet after the distributed power source is connected is calculated based on the short-circuit current flowing through the distribution line outlet protection after the distributed power source is connected, as follows: ， in, It is the protection sensitivity of the distribution line outlet after the distributed power source is connected.

5. According to claim 4, a method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection is characterized in that: The protection impact of the distribution line outlet is evaluated based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, including: If the protection sensitivity of the distribution line outlet after the distributed power source is connected is greater than or equal to the preset value, it is determined that there is no impact on the protection; If the protection sensitivity of the distribution line outlet after the distributed power source is connected is less than the preset value, the protection setting value of the current segment III is adjusted, and the protection sensitivity after the protection setting value adjustment is recalculated; If the protection sensitivity after the protection setting value is adjusted is greater than or equal to the preset value, it is judged as a general impact and can be used normally after the adjusted protection setting value is adopted; If the protection sensitivity after the protection setting is adjusted is less than the preset value, it is judged as a serious impact and the protection configuration needs to be replaced.

6. The evaluation method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection according to claim 5 is characterized in that: The preset value is 1.

5.

7. According to claim 5, a method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection is characterized in that: The adjustment of the protection setting value of the current section III includes: Assume that the current III protection setting is times the maximum load current of the distribution line, within the following range Make adjustments and get the adjusted value ,Will Times the maximum load current of the distribution line is used as the adjusted current stage III protection setting value. 。 8. The evaluation method for quantitatively analyzing the impact of distributed power access on distribution line outlet protection according to claim 7 is characterized in that: The recalculating the protection sensitivity after the protection setting value is adjusted includes: ； in, It is the protection sensitivity after the protection setting is adjusted. It is the protection setting value of the adjusted current section III.

9. An evaluation device for quantitatively analyzing the impact of distributed power access on distribution line outlet protection, characterized in that: The device is used to implement the evaluation method for quantitatively analyzing the impact of distributed power supply access on distribution line outlet protection as described in any one of claims 1 to 8, comprising: The first calculation module is used to calculate the protection sensitivity of the distribution line outlet when the distributed power source is not connected; A second calculation module is used to calculate the penetration rate of the connected distributed power source, and based on the penetration rate of the distributed power source and the protection sensitivity of the distribution line outlet when the distributed power source is not connected, calculate the protection sensitivity of the distribution line outlet after the distributed power source is connected; An evaluation module is used to evaluate the impact of distribution line outlet protection on distribution line outlet protection based on the protection sensitivity of the distribution line outlet after the distributed power source is connected, and the evaluation results include: no impact on the distribution line outlet protection after the distributed power source is connected, a general impact on the distribution line outlet protection after the distributed power source is connected, and the protection setting needs to be adjusted; and a serious impact on the distribution line outlet protection after the distributed power source is connected, and the protection configuration needs to be replaced.

10. The evaluation device for quantitatively analyzing the impact of distributed power access on distribution line outlet protection according to claim 9, characterized in that: The evaluation module is specifically used for: The impact of distribution line outlet protection is assessed as follows: If the protection sensitivity of the distribution line outlet after the distributed power source is connected is greater than or equal to the preset value, it is determined that there is no impact on the protection; If the protection sensitivity of the distribution line outlet after the distributed power source is connected is less than the preset value, the protection setting value of the current segment III is adjusted, and the protection sensitivity after the protection setting value adjustment is recalculated; If the protection sensitivity after the protection setting value is adjusted is greater than or equal to the preset value, it is judged as a general impact and can be used normally after the adjusted protection setting value is adopted; If the protection sensitivity after the protection setting is adjusted is less than the preset value, it is judged as a serious impact and the protection configuration needs to be replaced; The protection setting value of the current segment III is adjusted as follows: Assume that the current III protection setting is times the maximum load current of the distribution line, within the following range Make adjustments and get the adjusted value ,Will Times the maximum load current of the distribution line is used as the adjusted current stage III protection setting value. 。 11. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions which, when executed by a computing device, cause the computing device to perform any one of the methods according to claims 1 to 8.

12. A computing device, characterized in that: include, One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any one of the methods according to claims 1 to 8.

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