Power distribution system

Abstract

The present application relates to a power distribution system, comprising a distribution transformer circuit, a load circuit and a first energy storage device, wherein an output end of the distribution transformer circuit may be connected to an input end of the load circuit, so as to transmit electric energy to the load circuit, and the first energy storage device may be connected to a connection point between two load branches in the load circuit, so as to supply electric energy to the load circuit or absorb electric energy from the load circuit. It can be seen that in the embodiments of the present application, by means of providing a first energy storage device between two load branches in a load circuit, electric energy can be supplied to the load circuit or electric energy can be absorbed from the load circuit by means of the first energy storage device; therefore, the electric energy of a power distribution system can be adjusted to satisfy a change in a load, and the load pressure on an upstream circuit of an access point can also be greatly relieved, thereby facilitating an improvement in the reliability of the power distribution system.

Description

Power distribution system

[0001] Cross-reference to related applications

[0002] This application is based on Chinese Patent Application No. 2024208415204 entitled "Power distribution system" filed on April 22, 2024, which is incorporated by reference in its entirety into this application. TECHNICAL FIELD

[0003] The present application relates to the technical field of power distribution, and in particular to a power distribution system. BACKGROUND

[0004] With the development of society, the demand for electricity continues to grow, and the requirement for the power supply capacity (or called carrying capacity or load capacity) of the power distribution system is also increasing. However, the power supply capacity of the power distribution system has an upper limit after being constructed, and there may be a situation that the power supply capacity of the power distribution system cannot meet the demand for electricity.

[0005] Therefore, how to adjust the power of the power distribution system is a problem to be solved.

[0006] SUMMARY

[0007] In view of the above problems, the present application provides a power distribution system which can improve the power supply capacity of the power distribution system.

[0008] In a first aspect, the present application provides a power distribution system, which comprises a distribution transformer line, a load line and a first energy storage device, wherein the output end of the distribution transformer line is connected with the input end of the load line to transmit power with the load line; and the first energy storage device is connected with a connection point between two load branches in the load line to provide power for the load line or absorb power in the load line.

[0009] The power distribution system of the present application can provide power for the load line or absorb power in the load line through the first energy storage device arranged between the two load branches in the load line, which not only adjusts the power of the power distribution system to meet the load change, but also greatly relieves the load pressure of the line upstream of the access point, thereby improving the reliability of the power distribution system.

[0010] In some embodiments, the first energy storage device is configured to provide power for the load branch downstream of the connection point in the load line, thereby increasing the power supply capacity of the power distribution system and realizing flexible expansion of the energy storage device to the load line.

[0011] In some embodiments, the current of the connection point is greater than the difference between the maximum detection current of the input end of the load line and the maximum output current of the first energy storage device, so that the load pressure of the line upstream of the access point can be reduced to meet the requirements, which is conducive to balancing the load pressure of the line, thereby improving the stability of the power distribution system.

[0012] In some embodiments, the current range of the maximum output current of the first energy storage device is related to the maximum detection current, the minimum detection current and the preset maximum current threshold of the input end of the load line, so that the load rate requirement of the input end of the load line can be met on the basis of saving the cost of the first energy storage device, thereby improving the stability of the power distribution system.

[0013] In some embodiments, the upper threshold of the current range is the difference between the maximum detection current and the minimum detection current, and the lower threshold of the current range is the difference between the maximum detection current and the target maximum current threshold, wherein the target maximum current threshold is equal to the product of the preset maximum current threshold and the preset load rate threshold.

[0014] In the embodiments of the present application, the lower threshold of the current range is the difference between the maximum detection current and the target maximum current threshold, so that the load rate of the input end of the load line is less than or equal to the preset load rate threshold, thereby improving the stability of the load line. The upper threshold of the current range of the maximum output current of the first energy storage device is the difference between the maximum detection current and the minimum detection current, which can save the cost of the first energy storage device.

[0015] In some embodiments, the power distribution system includes a plurality of first energy storage devices and a plurality of load branches, and at least one first energy storage device is connected between the connection points of two load branches in the load line, thereby further increasing the power adjustment capability of the power distribution system, and further relieving the load pressure of the line upstream of the access point of different first energy storage devices, thereby further balancing the load pressure of the load line.

[0016] In some embodiments, the power distribution system includes a plurality of load lines and a plurality of first energy storage devices, wherein at least one first energy storage device is connected between the connection points of two load branches in the load line.

[0017] In the embodiments of the present application, on the basis of the load branches provided with power by the distribution line, the power adjustment capability of the power distribution system can be further increased by setting corresponding first energy storage devices on different load lines, and the load pressure of the line upstream of the access point of different load lines can be further relieved, thereby further balancing the load pressure distribution of the power distribution system.

[0018] In some embodiments, the first energy storage device comprises a load monitoring circuit to detect the load rate of the connection point, and adjust the working mode of the first energy storage device according to the load rate, so that the first energy storage device can transfer electric energy with the load line as needed, thereby saving the electric energy resources of the first energy storage device on the basis of relieving the load pressure of the access point upstream line.

[0019] In some embodiments, a meter is arranged between the first energy storage device and the connection point, so that the power change of the first energy storage device can be detected.

[0020] In some embodiments, the power distribution system further comprises a second energy storage device, wherein the second energy storage device is connected to the output end of the distribution transformer line to provide electric energy for the load line or absorb electric energy in the distribution transformer line.

[0021] In the embodiments of the present application, by increasing the second energy storage device at the output end of the distribution transformer line and the first energy storage device on the load line, the flexible expansion of the energy storage device to the distribution transformer line and the load line is realized, which can relieve the load pressure at different positions of the power distribution area and is conducive to balancing the load pressure of the power distribution system, thereby further improving the stability of the power distribution system.

[0022] In some embodiments, the distribution transformer line comprises a power distribution transformer; wherein the input end of the power distribution transformer is connected to the power grid, and the output end of the power distribution transformer is connected to the input end of the load line to convert the electric energy transmitted by the power grid into electric energy that can be used by the user equipment and then transmit it to the load line.

[0023] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0024] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered limiting the present application. Moreover, the same reference numbers are used to represent the same components throughout the drawings. In the drawings:

[0025] Fig. 1 is a schematic diagram of a power distribution system corresponding to a power distribution area according to an embodiment of the present application;

[0026] Fig. 2 is a schematic diagram of a power distribution system according to some embodiments of the present application;

[0027] Fig. 3 is a schematic diagram of the load change of a power distribution system according to an embodiment of the present application;

[0028] FIG. 4 is a structural schematic diagram of a power distribution system according to some embodiments of the present application;

[0029] FIG. 5 is a structural schematic diagram of a power distribution system according to some embodiments of the present application;

[0030] FIG. 6 is a schematic diagram of a working state of an energy storage device according to an embodiment of the present application;

[0031] FIG. 7 is a schematic diagram of a working state of an energy storage device according to an embodiment of the present application;

[0032] FIG. 8 is a structural schematic diagram of a power distribution system according to some embodiments of the present application;

[0033] FIG. 9 is a structural schematic diagram of a power distribution system according to some embodiments of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "comprise" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0037] The power distribution system involved in the embodiments of the present application can be a power distribution system corresponding to a power distribution area; of course, it can also be a power distribution system corresponding to other scenarios.

[0038] The following embodiments are described taking the power distribution system of the embodiments of the present application as an example of a power distribution system corresponding to a power distribution area for the convenience of description. It should be understood that when the power distribution system of the embodiments of the present application is a power distribution system corresponding to other scenarios, the implementation principles and technical effects are similar.

[0039] For the convenience of understanding, the related content of the power distribution area is first introduced and described exemplarily in the embodiments of the present application.

[0040] The power system usually transmits electric energy from the power plant end to the power user equipment location by extra-high voltage transmission lines, high voltage transmission lines and / or medium voltage transmission lines. After reaching the location, the electric energy in the lines is gradually reduced from the voltage levels of extra-high voltage, high voltage and medium voltage by transformers at different levels, and finally the medium voltage in the medium voltage transmission line is converted into low voltage electric energy that can be used by the power user equipment by the distribution transformer, and the low voltage electric energy is transmitted to each power demand side (i.e. power user equipment) by the low voltage outgoing circuit (or called load circuit).

[0041] Generally, the distribution area refers to the low voltage power transmission network composed of the distribution transformer and all the low voltage outgoing circuits downstream thereof. The number of low voltage outgoing circuits downstream of the distribution transformer is related to the capacity of the distribution transformer. It should be understood that the larger the capacity of the distribution transformer, the more the number of low voltage outgoing circuits downstream thereof; the smaller the capacity of the distribution transformer, the less the number of low voltage outgoing circuits downstream thereof.

[0042] Fig. 1 is a schematic diagram of the structure of a power distribution system corresponding to a distribution area according to an embodiment of the present application. As shown in Fig. 1, the input end of the distribution transformer 10 can be connected to the medium voltage transmission line 12 through the ring network cabinet 11, and the output end of the distribution transformer 10 can be connected to the input end of m parallel low voltage outgoing circuits 13, and n parallel loads (or load branches) are connected to each low voltage outgoing circuit 13. Wherein, m and n are integers greater than 1.

[0043] It should be understood that because the multiple low voltage outgoing circuits are connected in parallel, the multiple loads in each low voltage outgoing circuit 13 are also connected in parallel, so the input end current of each low voltage outgoing circuit 13 is the sum of the currents of all load branches in the low voltage outgoing circuit 13, and the output end current of the distribution transformer 10 is the sum of the input end currents of the multiple low voltage outgoing circuits 13. That is, in an inherent power distribution system, the closer to the distribution transformer, the larger the current of the line, the higher the load rate, and the higher the safety risk.

[0044] For ease of understanding, the following part takes the current on the first low voltage outgoing circuit 13 as an example for introduction, and the currents on the other low voltage outgoing circuits 13 are similar and will not be repeated here.

[0045] Suppose the current of each load when running is stable at 1, the total current at the input end of the low voltage outgoing circuit 13 is n, the line current between the first load and the second load is n-1, the line current between the second load and the third load is n-2, and the line current of the terminal load is 1.

[0046] The power system is a demand-response system (i.e. the power system delivers as much power as the load end needs, and the front-end power plant produces as much power as the load end needs). The distribution system of the distribution area is the same, the more the load in the distribution system, the more energy each load needs, the more energy the distribution transformer converts, and the more energy the low-voltage outgoing line circuit delivers.

[0047] However, after the construction of the distribution system of the distribution area is completed, the hardware devices (such as distribution transformers and low-voltage outgoing line circuits, etc.) are fixed and unchangeable, and they have their own upper limit of carrying capacity, that is, the maximum load capacity of the distribution area. The load is changing and continuously growing, and the distribution system designed according to experience at the initial stage may exceed the maximum operating capacity or even the maximum carrying capacity of the distribution transformer due to the growth or large fluctuations of the load after a certain period of time. When the load rate (the ratio of the real-time load to the maximum carrying capacity) is greater than the preset load rate threshold (for example, 70% or the like) for a long time, the distribution transformer and the low-voltage outgoing line circuit have high safety and reliability risks, and when the load rate exceeds the maximum carrying capacity (for example, reaches 100% or the like), the distribution transformer and the line have great safety risks. It should be noted that the preset load rate threshold can be slightly different according to the specific model and / or service life of the hardware devices of the distribution system, and correspondingly, the maximum carrying capacity can also be slightly different according to the specific model and / or service life of the hardware devices of the distribution system.

[0048] Therefore, how to adjust the power of the distribution system to meet the load change is a problem to be solved.

[0049] Considering that the energy storage device has the ability to store and release power, the embodiments of the present application propose to set an energy storage device between two load branches in the load line, which can provide power to the load line or absorb power in the load line through the energy storage device, thereby achieving the purpose of adjusting the power of the distribution system, so as to meet the load change.

[0050] In some embodiments, FIG. 2 is a structural schematic diagram of a distribution system provided by some embodiments of the present application, as shown in FIG. 2, the distribution system of the embodiments of the present application can include but is not limited to a distribution transformer line 20, a load line 21 and a first energy storage device 22. Wherein, the output end of the distribution transformer line 20 can be connected with the input end of the load line 21 to transmit power with the load line 21. Wherein, the power transmission between the distribution transformer line 20 and the load line 21 can include but is not limited to: the distribution transformer line 20 providing power to the load line 21, or the load line 21 providing power to the distribution transformer line (i.e. the distribution transformer line 20 absorbs the power of the load line 21).

[0051] In a possible implementation, the power provided by the distribution and transformation circuit 20 to the load circuit 21 can be power obtained from a power grid. In another possible implementation, the power provided by the distribution and transformation circuit 20 to the load circuit 21 can be power obtained from a power generation device. The power generation device can include, but is not limited to, at least one of a thermal power generation device, a wind power generation device, a hydraulic power generation device, a solar power generation device, and a nuclear power generation device.

[0052] Of course, the power provided by the distribution and transformation circuit 20 to the load circuit 21 can also be power obtained in other manners. It should be noted that, for ease of understanding, the power provided by the distribution and transformation circuit 20 to the load circuit 21 is taken as an example of power obtained from a power grid in the following embodiments of the present application, and the related content of the power distribution system is exemplarily introduced and described.

[0053] Exemplarily, the distribution and transformation circuit can include, but is not limited to, a power distribution transformer. An input end of the power distribution transformer can be connected to the power grid, and an output end of the power distribution transformer can be connected to an input end of the load circuit 21, so as to convert the power transmitted by the power grid into power that can be used by the user equipment and then transmit the power to the load circuit 21.

[0054] Exemplarily, the distribution and transformation circuit can include, but is not limited to, a power transmission line. An input end of the power transmission line can be connected to the power grid, and an output end of the power transmission line can be connected to an input end of the load circuit 21, so as to transmit the power transmitted by the power grid to the load circuit 21.

[0055] The load circuit 21 in the embodiments of the present application can be connected to a plurality of load branches 210 (n load branches are exemplarily shown in FIG. 2), so as to transmit the power meeting the user equipment to the user equipment (or referred to as a power load) in each load branch 210. Exemplarily, the plurality of load branches 210 in the embodiments of the present application can be connected to the load circuit 21 in parallel.

[0056] In some embodiments, the load branch 210 involved in the embodiments of the present application can be a household load or an industrial and commercial load, and the embodiments of the present application do not limit this.

[0057] The first energy storage device 22 in the embodiments of the present application can be connected to a connection point (or referred to as an access point) P between two load branches 210 in the load circuit 21 (for example, the connection point between the second load branch 210 and the third load branch 210 in the load circuit 21 where the first energy storage device 22 is arranged is exemplarily shown in FIG. 2), so as to provide power for the load circuit 21 or absorb power in the load circuit 21.

[0058] In a possible implementation, when the load rate of the connection point of the first energy storage device 22 is not less than a preset load rate threshold (or referred to as heavy load), the first energy storage device 22 can provide power for the load line 21, so that the load pressure of the line upstream of the access point can be relieved.

[0059] In some embodiments, the first energy storage device 22 can be configured to provide power for the load branches 210 downstream of the access point P in the load line 21.

[0060] For example, when the capacity of the first energy storage device 22 is large, the first energy storage device 22 can provide power for the load branches 210 downstream of the access point P, which not only increases the power supply capacity of the power distribution system, but also greatly relieves the load pressure of the line upstream of the access point P. The line upstream of the access point P can include, but is not limited to, the line between the input end of the load line 21 and the access point P and the transformer line 20.

[0061] For example, referring to FIG. 2, it is assumed that the current of each load branch 210 is stable at 1 when in operation, and that the total current of the input end of the load line 21 is n, the line current between the first load branch 210 and the second load branch 210 is n-1, the line current between the second load branch 210 and the third load branch 210 is n-2, and so on, and the current at the end of the load line 21 is 1, without the first energy storage device 22.

[0062] As shown in FIG. 2, it is assumed that the maximum output current of the first energy storage device 22 is o (the maximum output current of the first energy storage device 22 can refer to the output current of the first energy storage device when operating at the maximum discharge power), and that the total current of the input end of the load line 21 is n-o, the line current between the first load branch 210 and the second load branch 210 is n-o-1, the line current between the second load branch 210 and the third load branch 210 is still n-2, and so on, and the current at the end of the load line 21 is still 1, when the first energy storage device 22 is arranged at the connection point between the second load branch 210 and the third load branch 210 in the load line 21. It can be seen that, by increasing the first energy storage device, the current of the line upstream of the access point of the first energy storage device in the load line 21 can be reduced.

[0063] For another example, considering the cost factor of the first energy storage device 22, the capacity of the first energy storage device 22 is limited (i.e., the power supply capacity of the first energy storage device 22 is limited), and the transformer line 20 can provide power for the load branches 210 downstream of the access point P together with the first energy storage device 22, so that on the basis of increasing the power supply capacity of the power distribution system, the load pressure of the line upstream of the access point P can be relieved, and the cost of the power distribution system can be saved.

[0064] Of course, the distribution and transformation line 20 can also provide power for each load branch 210 located upstream of the access point P.

[0065] It can be seen that, in the embodiment of the application, on the basis of the distribution and transformation line 20 providing power for the load branch 210, the first energy storage device 22 can also provide power for part of the load branch, thereby increasing the power supply capacity of the power distribution system and realizing flexible expansion of the load line by the energy storage device.

[0066] In another possible implementation, when the load rate at the connection point of the first energy storage device 22 is less than the preset load rate threshold (or referred to as light load or low electricity consumption valley), the first energy storage device 22 can absorb the power in the load line 21, which not only increases the power storage amount of the first energy storage device 22 to facilitate subsequent discharge in heavy load, but also does not waste the power in the power distribution system, which is beneficial to improve the power utilization rate of the power distribution system.

[0067] Considering that the load branch 210 can not only consume power as an electrical load, but also generate power as a power generation end and output the power back to the high-voltage side through the load line 21 and the distribution and transformation line 20, the first energy storage device 22 in the embodiment of the application can absorb the power of the load branch 210 in the load line 21 to provide power transfer for power generation in the load branch 210.

[0068] It can be seen that, in the embodiment of the application, by absorbing the power in the load line 21 through the first energy storage device 22, the purpose of adjusting the power of the power distribution system can be achieved, so as to meet the load change.

[0069] It can be seen that, in the embodiment of the application, by arranging the first energy storage device between the two load branches in the load line, the first energy storage device can provide power for the load line or absorb the power in the load line, which not only adjusts the power of the power distribution system to meet the load change, but also greatly relieves the load pressure of the line upstream of the access point, thereby being beneficial to improve the reliability of the power distribution system.

[0070] On the basis of the above embodiment, in order to facilitate understanding, the following embodiments of the application take the first energy storage device providing power for the load line as an example to exemplarily introduce and describe the related content of the power distribution system.

[0071] Figure 3 is a schematic diagram of the load changes of the power distribution system provided in the embodiments of this application. Under normal circumstances, the load of the power distribution system is not constant; it is affected by the type of load in the distribution area, the electricity consumption behavior of users over time, etc. A common characteristic of residential load is shown in Figure 3 (large temporal fluctuations with obvious regularity: the load rate during normal periods can be 45%–50%, the load rate during off-peak periods is less than 40%, the load rate during peak periods can be above 80%, and the peak load rate can be 89.1%). It is evident that the load in the distribution area has high volatility, which will have a significant impact on the overall power system during peak periods. The distribution transformer and its downstream low-voltage circuits are under high load at this time, and when they exceed their maximum load capacity by a certain percentage, faults or safety accidents may occur. In this embodiment of the application, by adding energy storage devices, the peak-valley time-shifting characteristics of energy storage can be utilized to make the load peak-valley of the load line complementary, so as to keep the load rate of the power distribution system below the safety line shown in Figure 3. This can minimize the occurrence of power outages and / or safety accidents caused by heavy overload of the load line during peak electricity consumption, which is conducive to the reliable operation of the power system.

[0072] Considering that the load branches 210 on the load line 21 are distributed in parallel, the upstream line has a high load and the downstream line has a low load, and the connected energy storage device can reduce the load splitting effect of the upstream line at the access point, the principle of the optimal access point of the energy storage device can be to make the line load distribution uniform.

[0073] In some embodiments of this application, the current at the connection point (or access point) P can be greater than the maximum detection current n at the input terminal of the load line 21. max The difference between the maximum output current o of the first energy storage device 22 and the first energy storage device 22 is used to enable the first energy storage device 22 to be installed at locations where load pressure needs to be reduced (or at locations with higher risks). This can reduce the load pressure of the upstream line at the access point to meet the requirements, which is beneficial for balancing the line load pressure and thus improving the stability of the power distribution system.

[0074] The maximum output current of the first energy storage device 22 can refer to the output current of the first energy storage device when it is operating at its maximum discharge power. Maximum detection current n max It can refer to the current at the input terminal of the load line when the load of each load branch in the load line is at its maximum.

[0075] For example, referring to the power distribution system shown in Figure 2 above, when n-2 is greater than or equal to n... max In the case of -o, the first energy storage device can be set at the connection point between the second load branch and the third load branch.

[0076] In some embodiments, considering the load rate factor at the input of the load line 21 and the cost factor of the first energy storage device, the current range of the maximum output current o of the first energy storage device 22 in this embodiment can be the same as the maximum detection current n at the input of the load line 21. max Minimum detection current n min This is related to the preset maximum current threshold N, so that the load rate requirements at the input of the load line 21 can be met while saving the cost of the first energy storage device, thereby improving the stability of the power distribution system. The preset maximum current threshold N can refer to the maximum overcurrent capacity of the input of the load line 21. Minimum detection current n min It can refer to the current at the input terminal of the load line when the load of each load branch in the load line is at its minimum.

[0077] On the one hand, considering that the load rate at the input of the load line 21 must be less than or equal to the preset load rate threshold, the maximum output current o of the first energy storage device 22 cannot be too small, i.e. (n max -o) / N needs to be less than or equal to a preset load rate threshold, that is, the lower limit threshold of the current range of the maximum output current o of the first energy storage device 22 in this embodiment can be the maximum detection current n. max The difference between the target maximum current threshold and the target maximum current threshold, where the target maximum current threshold can be equal to the product of a preset maximum current threshold N and a preset load rate threshold. For example, the maximum output current o of the first energy storage device 22 can be greater than or equal to (n... max -Preset load rate threshold * N).

[0078] On the other hand, considering that load fluctuations are within a certain range and the cost of energy storage devices, the maximum output current o of the first energy storage device 22 should not be too large. That is, in this embodiment, the upper limit of the current range of the maximum output current o of the first energy storage device 22 can be the maximum detection current n. max With minimum detection current n min The difference. For example, the maximum output current o of the first energy storage device 22 can be less than (n max -n min ).

[0079] In some embodiments, FIG. 4 is a structural schematic diagram of a power distribution system according to some embodiments of the present application. As shown in FIG. 4, the power distribution system according to embodiments of the present application can include multiple load branches. In the case that the load pressure at multiple connection points in the load line 21 is high, the power distribution system according to embodiments of the present application can include multiple first energy storage devices 22 (for the convenience of drawing, two first energy storage devices 22 are shown in FIG. 4, where i can be an integer greater than 2 and less than n). At least one first energy storage device 22 can be connected to the connection points between two load branches 210 in the load line 21, thereby further increasing the power adjustment capability of the power distribution system, further relieving the load pressure of the upstream line of the access point of different first energy storage devices, and further facilitating the balancing of the load pressure of the load line.

[0080] It should be noted that in the case that the corresponding second energy storage device is provided at the multiple connection points in the load line 21, the corresponding access point position and maximum output current of each second energy storage device can refer to the related content in the above embodiments, which will not be described here again.

[0081] In some embodiments, FIG. 5 is a structural schematic diagram of a power distribution system according to some embodiments of the present application. As shown in FIG. 5, the power distribution system according to embodiments of the present application can include multiple load lines 21 and multiple first energy storage devices 22. At least one first energy storage device 22 can be connected to the connection points between two load branches 210 in the load line 21 to provide power or absorb power in the corresponding load line 21.

[0082] It should be understood that the connection point positions of the first energy storage devices 22 in different load lines 21 can be different. The specific connection point positions can be determined according to the load pressure of the corresponding load line 21, and the specific determination method can refer to the related content in the above embodiments, which will not be described here again.

[0083] In addition, the number of first energy storage devices 22 in different load lines 21 can be different. The specific number can be determined according to the load pressure of the corresponding load line 21.

[0084] It can be seen that in embodiments of the present application, on the basis of the power distribution line 20 providing power for the load branches 210, the power adjustment capability of the power distribution system can be further increased by providing corresponding first energy storage devices 22 on different load lines 21, the load pressure of the upstream line of each access point on different load lines can be further relieved, and the load pressure distribution of the power distribution system is further facilitated to be uniform.

[0085] In view of the fact that there is no monitoring unit on the low-voltage outgoing line in the power distribution system of the traditional power distribution area, the actual operation state, real-time load rate, and load rate change of the low-voltage outgoing line are unknown, the load pressure monitoring problem of the low-voltage outgoing line is further considered in the embodiments of the present application.

[0086] In some embodiments, the first energy storage device 22 in the embodiments of the present application can include but is not limited to a load monitoring circuit to detect the load rate of the connection point and adjust the working mode of the first energy storage device 22 according to the load rate. The load rate information can be used to indicate the ratio information of the real-time load to the maximum carrying capacity. The working mode of the first energy storage device 22 can include but is not limited to the working state and / or the working power; the working state of the first energy storage device 22 can include but is not limited to the charging state, the discharging state, or the standby state.

[0087] For example, the load monitoring circuit in the first energy storage device 22 can detect the load rate of the connection point by monitoring the current of the connection point, and adjust the working mode of the first energy storage device 22 according to the load rate and the state of charge (SOC) of the energy storage device 22, so that the first energy storage device 22 can transfer electric energy with the load line as needed, thereby saving the electric energy resources of the first energy storage device on the basis of relieving the load pressure of the line upstream of the access point.

[0088] For example, when the working state of the first energy storage device 22 is in the charging state, the load line can supply power to the first energy storage device 22 so that the first energy storage device 22 can store electric energy. For another example, when the working state of the first energy storage device 22 is in the discharging state, the first energy storage device 22 can supply power to the load line.

[0089] Fig. 6 is a schematic diagram of the working state of the energy storage device according to the embodiments of the present application, as shown in Fig. 6, when the load rate of the connection point is less than the preset load rate threshold (or referred to as light load) and the SOC state of the first energy storage device is less than the first preset SOC threshold, the first energy storage device can be adjusted to the charging state to fully utilize the capacity of the corresponding load line 21 and absorb the electric energy in the load line 21 for electric energy storage. For example, the preset load rate threshold can include but is not limited to any value in 65% to 75%, and the first preset SOC threshold can include but is not limited to any value in 92% to 97%. For example, the preset load rate threshold can be 70%, and the first preset SOC threshold can be 95%.

[0090] It should be noted that any preset SOC threshold (e.g., the first preset SOC threshold and / or the second preset SOC threshold) involved in the implementation of the present application can be adjusted according to the model, performance, environment, service life and / or health status of the first energy storage device, etc.

[0091] Fig. 7 is a schematic diagram of the working state of the energy storage device provided by the embodiment of the present application. As shown in Fig. 7, when the load rate at the connection point is not less than the preset load rate threshold (or referred to as heavy load) and the SOC state of the first energy storage device is greater than the second preset SOC threshold (i.e., having a certain amount of power reserve), the first energy storage device can be adjusted to the discharging state as a power supply to provide power for the load line, so that the load pressure of the line upstream of the access point of the first energy storage device will be relieved (the load rate of the line downstream of the access point is determined by the load demand and is not affected). Exemplarily, the second preset SOC threshold can include but is not limited to any value in 5% to 15%. For example, the second preset SOC threshold can be 10%.

[0092] It should be understood that when the load rate at the connection point is less than the preset load rate threshold (i.e., non-heavy load) and the SOC state of the first energy storage device is greater than the second preset SOC threshold, i.e., the first energy storage device does not need to be charged, the first energy storage device can be adjusted to the standby state to continuously monitor the load rate of the load line. When the load rate at the connection point is not less than the preset load rate threshold and the SOC state of the first energy storage device is not greater than the second preset SOC threshold, i.e., the first energy storage device does not need to be discharged, the first energy storage device can be adjusted to the standby state to continuously monitor the load rate of the load line.

[0093] In addition, by detecting the load rate at the connection point through the load monitoring circuit in the first energy storage device 22, not only can the first energy storage device adjust the working mode, but also it is beneficial to master the load condition of the load line, data collection and analysis, diagnosis, prediction, etc. (i.e., the monitoring data of the load rate can be used as the main data support for future distribution area management and transformation).

[0094] Considering that as the number of load branches on different load lines increases, the load rate of the distribution line increases, and there may be heavy load conditions, in the embodiment of the present application, a second energy storage device is further arranged on the distribution line to relieve the load pressure of the distribution line.

[0095] In some embodiments, Fig. 8 is a structural schematic diagram of a power distribution system according to some embodiments of the present application. As shown in Fig. 8, the power distribution system according to embodiments of the present application can further include a second energy storage device 23, wherein the second energy storage device 23 can be connected to the output end of the distribution transformer line 20 to provide power for the load line or absorb power in the distribution transformer line 20. The power absorbed in the distribution transformer line 20 can come from the upstream of the distribution transformer line 20 and / or the downstream load line.

[0096] In some embodiments, the first energy storage device 22 and the second energy storage device 23 can be set as needed. If the load rate of the distribution transformer line side is too large, which can be greater than a preset load rate threshold, and the load rate of the load line 21 is normal, which can be less than or equal to the preset load rate, the second energy storage device 23 can be set only on the distribution transformer line side. Similarly, according to the foregoing embodiments, the first energy storage device 22 can also be set only on the load line 21 side.

[0097] For example, the second energy storage device 23 can provide power for the load line 21 together with the distribution transformer line 20 when the load rate of the distribution transformer line 20 is greater than the preset load rate threshold, which can help to prolong the service life of the second energy storage device.

[0098] As can be seen, when the total load of the distribution transformer line is constant, the second energy storage device can be used as a power supply point and connected in parallel with the distribution transformer line to output, which can relieve the power supply pressure of the distribution transformer line, reduce the load rate of the distribution line, and achieve flexible expansion of the energy storage device for the distribution transformer line.

[0099] It should be noted that the load pressure of the distribution transformer line can be relieved only by setting the energy storage device at the output end of the distribution transformer line 20.

[0100] Considering that the load line is usually long, the current at the input end of the load line (close to the distribution transformer line) is also the sum of the currents of all downstream load branches, and the rated current of the load line is designed to be small (usually when there are m load branches in the distribution transformer line, the rated current of the load line is designed to be about 1 / m of the distribution transformer line), therefore, when the distribution transformer line is under heavy load, the load pressure of the distribution transformer line is large, and the load rate is high, at the same time, the load line also has the above-mentioned problem (the maximum carrying capacity of the load line is designed according to the distribution transformer line, and there is a possibility of further deteriorating the load rate of the line due to the addition or adjustment of the load branch).

[0101] In the embodiments of the present application, the flexible expansion of the energy storage device to the distribution transformer line and the load line is realized by adding the second energy storage device at the output end of the distribution transformer line and adding the first energy storage device at the load line (i.e., the combination of the distribution transformer line storage and the low-voltage outgoing line loop storage), which can relieve the load pressure at different positions of the power distribution area, balance the load pressure of the power distribution system, and further improve the stability of the power distribution system.

[0102] In some embodiments, a metering table can be further arranged between the first energy storage device and the connection point on the load line in the embodiments of the present application, so that the power consumption of the first energy storage device can be metered.

[0103] In some embodiments, a metering table can also be arranged between the second energy storage device and the connection point on the distribution transformer line in the embodiments of the present application, so that the power consumption of the second energy storage device can be metered.

[0104] In some embodiments, FIG. 9 is a structural schematic diagram of a power distribution system provided by another embodiment of the present application. On the basis of the above-mentioned embodiments, the structure of the power distribution system is exemplarily introduced and described by taking the distribution transformer line 20 including a distribution transformer and the combination of the distribution transformer line storage and the low-voltage outgoing line loop storage as an example in the embodiments of the present application.

[0105] As shown in FIG. 9, the power distribution system in the embodiments of the present application can include a distribution transformer line 20, m load lines, a plurality of first energy storage devices 22, and a second energy storage device 23. The input end of the distribution transformer line 20 can be connected with the medium-voltage transmission line 12 through the ring network cabinet 11, and the second energy storage device 23 can be connected with the output end of the distribution transformer line 20. Each first energy storage device 22 can be connected with the connection point between two load branches in the corresponding load line 21. It should be understood that the first energy storage device 22 is exemplarily shown as being arranged at the connection point between the second load branch and the third load branch in the corresponding load line 21 in FIG. 9.

[0106] Referring to FIG. 9, it is assumed that the stable current of each load branch in each load line 21 is 1, and the total current of the input end of each load line 21 is n, the total current of the output end of the distribution transformer line is n*m, the line current between the first load branch and the second load branch in each load line 21 is n-1, the line current between the second load branch and the third load branch is n-2, and the terminal current of the load line 21 is 1 in the case that the first energy storage device 22 and the second energy storage device 23 are not connected.

[0107] As shown in FIG. 9, assuming that the maximum output current of the first energy storage device 22 is o1, the maximum output current of the second energy storage device 23 is o2, the second energy storage device 23 is connected to the output end of the distribution transformer line 20, and the first energy storage device 22 is arranged at the connection point between the second load branch and the third load branch in each load line 21, the total current at the output end of the distribution transformer line is (n-o1)*m-o2, the total current at the input end of each load line 21 is n-o1, the line current between the first load branch and the second load branch in each load line 21 is n-o1-1, the line current between the second load branch and the third load branch is still n-2, and the terminal current of the load line 21 is still 1.

[0108] In some embodiments, the first energy storage device 22 and the second energy storage device 23 can be the same type of energy storage device, which can include but is not limited to electrochemical energy storage, and the electrochemical energy storage can include but is not limited to lithium ion batteries and sodium ion batteries.

[0109] In some embodiments, the energy storage scale of the second energy storage device 23 can be greater than the energy storage scale of the first energy storage device 22, wherein the energy storage scale can include but is not limited to the maximum storable power and / or the maximum charge-discharge power.

[0110] It should be understood that the energy storage scale of any energy storage device in the embodiments of the present application can be determined according to the preset distribution transformer ratio and the load rate fluctuation of the target line to which the energy storage device is connected, so that the load peak and valley of the target line can be complemented.

[0111] As can be seen, by increasing the first energy storage device and the second energy storage device, the current of the distribution transformer line and the line upstream of the connection point of the first energy storage device in each load line 21 can be reduced, which is conducive to relieving the load pressure at different positions of the power distribution area and achieving the effect of balancing the load pressure of the power distribution system.

[0112] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A power distribution system, wherein, The power distribution system comprises a distribution line, a load line and a first energy storage device, wherein an output end of the distribution line is connected to an input end of the load line to transmit electric energy with the load line; the first energy storage device is connected to a connection point between two load branches in the load line to provide electric energy for the load line or absorb electric energy in the load line.

2. The power distribution system of claim 1, wherein, The first energy storage device is configured to provide electric energy for a load branch in the load line downstream of the connection point.

3. The power distribution system of claim 1 or 2, wherein, A current of the connection point is greater than a difference between a maximum detected current of the input end of the load line and a maximum output current of the first energy storage device.

4. The power distribution system of claim 3, wherein, A current range of the maximum output current of the first energy storage device is related to a maximum detected current, a minimum detected current and a preset maximum current threshold of the input end of the load line.

5. The power distribution system of claim 4, wherein, An upper threshold of the current range is a difference between the maximum detected current and the minimum detected current; a lower threshold of the current range is a difference between the maximum detected current and a target maximum current threshold, wherein the target maximum current threshold is equal to a product of the preset maximum current threshold and a preset load rate threshold.

6. The power distribution system of any one of claims 1-5, wherein, The power distribution system comprises a plurality of the first energy storage devices and a plurality of the load branches, and at least one of the first energy storage devices is connected to the connection point between two of the load branches in the load line.

7. The power distribution system of any one of claims 1-5, wherein, The power distribution system comprises a plurality of the load lines and a plurality of the first energy storage devices, and at least one of the first energy storage devices is connected to the connection point between two of the load branches in the load line.

8. The power distribution system of any one of claims 1-7, wherein, The first energy storage device comprises a load monitoring circuit to detect a load rate of the connection point and adjust an operation mode of the first energy storage device according to the load rate.

9. The power distribution system of any one of claims 1-8, wherein, A meter is arranged between the first energy storage device and the connection point.

10. The power distribution system of any one of claims 1-9, wherein, The power distribution system further comprises a second energy storage device, wherein the second energy storage device is connected to the output end of the distribution line to provide electric energy for the load line or absorb electric energy in the distribution line.

11. The power distribution system of any one of claims 1-10, wherein, The distribution line comprises a power distribution transformer, wherein an input end of the power distribution transformer is connected to a power grid, and an output end of the power distribution transformer is connected to the input end of the load line.

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