Power distribution system

Abstract

The utility model relates to a power distribution system which comprises a distribution transformer line, a load line and first energy storage equipment. Wherein the output end of the distribution transformer line can be connected with the input end of the load line so as to transmit electric energy with the load line. The first energy storage device can be connected with 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. Visibly, in the embodiment of the invention, through a mode of arranging the first energy storage equipment between the two load branches in the load circuit, the electric energy can be provided for the load circuit or the electric energy in the load circuit can be absorbed through the first energy storage equipment, so that the electric energy of the power distribution system can be adjusted to meet the load change; and the load pressure of the upstream line of the access point can be greatly relieved, so that the reliability of a power distribution system can be improved.

Description

Technical Field

[0001] The present application relates to the field of power distribution technology, and in particular to a power distribution system. Background Art

[0002] As society develops, electricity demand continues to grow, placing increasing demands on the power supply capacity (also known as carrying capacity or load capacity) of distribution systems. However, after construction, distribution systems have a capacity limit, and there may be situations where the power supply capacity of the distribution system cannot meet electricity demand.

[0003] Therefore, how to adjust the power of the distribution system is an urgent problem to be solved. Utility Model Content

[0004] In view of the above problems, the present application provides a power distribution system that can improve the power supply capacity of the power distribution system.

[0005] In a first aspect, the present application provides a power distribution system, which includes a distribution transformer line, a load line and a first energy storage device, wherein the output end of the distribution transformer line is connected to the input end of the load line to transmit electrical energy to the load line; the first energy storage device is connected to the connection point between two load branches in the load line to provide electrical energy to the load line or absorb electrical energy in the load line.

[0006] The power distribution system of the embodiment of the present application, by setting a first energy storage device between two load branches in the load line, can provide power to the load line or absorb power in the load line through the first energy storage device. This can not only adjust the power of the distribution system to meet load changes, but also greatly alleviate the load pressure of the upstream line of the access point, thereby helping to improve the reliability of the power distribution system.

[0007] In some embodiments, the first energy storage device is configured to provide electrical energy to a load branch located downstream of a connection point in the load line, thereby increasing the power supply capacity of the power distribution system and achieving flexible expansion of the load line by the energy storage device.

[0008] In some embodiments, the current at 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 first energy storage device can be set at a position where the load pressure needs to be reduced. The load pressure of the line upstream of the access point can be reduced to meet the requirements, which is conducive to balancing the line load pressure, thereby improving the stability of the distribution system.

[0009] 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 facilitating improving the stability of the power distribution system.

[0010] In some embodiments, the upper limit threshold of the current range is the difference between the maximum detection current and the minimum detection current; the lower limit 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.

[0011] In the embodiments of the present application, by setting the lower limit threshold of the current range to be the difference between the maximum detection current and the target maximum current threshold, the load rate at the input end of the load circuit can be made less than or equal to the preset load rate threshold, thereby improving the stability of the load circuit. By setting the upper limit threshold of the current range of the maximum output current of the first energy storage device to be the difference between the maximum detection current and the minimum detection current, the cost of the first energy storage device can be reduced.

[0012] In some embodiments, the power distribution system includes multiple first energy storage devices and multiple load branches, and at least one first energy storage device is respectively connected to a connection point between two load branches in the load line, thereby further increasing the power adjustment capability of the power distribution system, and further alleviating the load pressure of the upstream line of the access points of different first energy storage devices, thereby further facilitating the balancing of the load pressure of the load line.

[0013] 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 respectively connected to a connection point between two load branches in the load line.

[0014] In an embodiment of the present application, on the basis of the distribution transformer line providing electric energy to the load branch, the electric energy adjustment capability of the distribution system can be further increased by setting corresponding first energy storage devices on different load lines, and the load pressure of the upstream lines of each access point on different load lines can be further alleviated, thereby further facilitating the uniform distribution of the load pressure of the distribution system.

[0015] In some embodiments, the first energy storage device includes 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 transmit power to the load line to which it belongs as needed, thereby alleviating the load pressure of the upstream line of the access point and saving the power resources of the first energy storage device.

[0016] In some embodiments, a meter is provided between the first energy storage device and the connection point so as to detect power changes of the first energy storage device.

[0017] In some embodiments, the power distribution system further includes a second energy storage device, wherein the second energy storage device is connected to the output end of the distribution transformer line to provide power to the load line or absorb power in the distribution transformer line.

[0018] In the embodiment of the present application, by adding a second energy storage device at the output end of the distribution transformer line and adding a first energy storage device on the load line, flexible expansion of the distribution transformer line and the load line by the energy storage device is achieved, which can alleviate the load pressure at different locations of the distribution station area, is conducive to balancing the load pressure of the distribution system, and further improves the stability of the distribution system.

[0019] In some embodiments, the distribution and transformation line includes a distribution transformer; wherein the input end of the distribution transformer is connected to the power grid, and the output end of the distribution transformer is connected to the input end of the load line, so as to convert the electric energy transmitted by the power grid into electric energy that can be used by the power user equipment and then transmit it to the load line.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0022] Figure 1 A schematic diagram of the power distribution system structure corresponding to the power distribution area provided in the embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of a power distribution system provided in some embodiments of the present application;

[0024] Figure 3 A schematic diagram of load changes in a power distribution system provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the structure of a power distribution system provided in some other embodiments of the present application;

[0026] Figure 5 A schematic diagram of the structure of a power distribution system provided in some other embodiments of the present application;

[0027] Figure 6 Schematic diagram of the working state of the energy storage device provided in the embodiment of the present application Figure 1 ;

[0028] Figure 7 Schematic diagram of the working state of the energy storage device provided in the embodiment of the present application Figure 2 ;

[0029] Figure 8 A schematic diagram of the structure of a power distribution system provided in some other embodiments of the present application;

[0030] Figure 9 A schematic structural diagram of a power distribution system provided in some other embodiments of the present application. DETAILED DESCRIPTION

[0031] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the term "include" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0033] In the description of the embodiments of the present application, technical terms such as "first" and "second" 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.

[0034] The power distribution system involved in the embodiments of the present application may be a power distribution system corresponding to a power distribution station area; of course, it may also be a power distribution system corresponding to other scenarios.

[0035] For the sake of convenience, the following embodiments are described using the power distribution system of the present application embodiment as a power distribution system corresponding to a power distribution station area. It should be understood that when the power distribution system of the present application embodiment is a power distribution system corresponding to other scenarios, its implementation principles and technical effects are similar.

[0036] For ease of understanding, the embodiments of the present application first provide an exemplary introduction to the relevant contents of the distribution station area.

[0037] The power system usually uses ultra-high voltage transmission lines, high voltage transmission lines and / or medium voltage transmission lines to transmit electric energy from the power plant to the location of the power user's equipment. After arriving at the location, the electric energy in the line is gradually reduced from ultra-high voltage, high voltage, and medium voltage levels by transformers at each level. Finally, the medium voltage electricity in the medium voltage transmission line is converted by distribution transformers into low voltage electricity that can be used by the power user's equipment. The low voltage electric energy is then transmitted to each electricity demander (i.e., the power user's equipment) through the low voltage outgoing line circuit (or load line).

[0038] Typically, a distribution area refers to the low-voltage power transmission network consisting of a distribution transformer and all downstream low-voltage outgoing line circuits. The number of low-voltage outgoing line circuits downstream of a distribution transformer is related to the capacity of the distribution transformer. It should be understood that the larger the capacity of a distribution transformer, the greater the number of downstream low-voltage outgoing line circuits; the smaller the capacity of a distribution transformer, the fewer the number of downstream low-voltage outgoing line circuits.

[0039] Figure 1 The schematic diagram of the power distribution system structure corresponding to the power distribution area provided in the embodiment of the present application is as follows: Figure 1 As shown, the input end of the distribution transformer 10 can be connected to the medium voltage transmission line 12 through the ring main unit 11, and the output end of the distribution transformer 10 can be connected to the input end of m parallel low voltage outgoing line circuits 13. Each low voltage outgoing line circuit 13 is connected to n parallel loads (or load branches). Wherein, m and n are both integers greater than 1.

[0040] It should be understood that because multiple low-voltage outgoing line circuits are connected in parallel, the multiple loads in each low-voltage outgoing line circuit 13 are also connected in parallel. Therefore, the input current of each low-voltage outgoing line circuit 13 is the sum of the currents of all load branches in that low-voltage outgoing line circuit 13, and the output current of the distribution transformer 10 is the sum of the input currents of the multiple low-voltage outgoing line circuits 13. In other words, in a conventional power distribution system, the closer to the distribution transformer, the greater the current in the line, the higher the load factor, and the higher the safety risk.

[0041] For ease of understanding, the following section takes the current on the first low-voltage output loop 13 as an example for introduction. The currents on other low-voltage output loops 13 are similar and will not be described in detail here.

[0042] Assume that the current of each load is stable at 1 during operation, the total current at the input end of the low-voltage outgoing line 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 end load is 1.

[0043] The power system is a demand-responsive system (i.e., the power system delivers the same amount of power required by the load, and the corresponding amount of power produced by the power plant at the front end). The same is true for the distribution system in the distribution area. The more loads in the distribution system, the more energy each load requires, the more energy the distribution transformer converts, and the more energy is delivered by the low-voltage outgoing line circuit.

[0044] However, after the construction of the distribution system in the distribution area is completed, its hardware equipment (such as distribution transformers and low-voltage outgoing line circuits) is fixed and has its own upper limit on load capacity, that is, the maximum load capacity of the distribution area. However, the load is variable and continuously growing. After a certain period of time, the distribution system designed based on experience may encounter a situation where the load exceeds the maximum operating capacity or even the maximum load capacity of the distribution transformer due to load growth or large fluctuations. When the load rate (the ratio of real-time load to maximum load capacity) is greater than the preset load rate threshold (for example, 70%) for a long time and continues to work, the distribution transformer and low-voltage outgoing line circuit have high safety and reliability risks. When the load rate exceeds its maximum load capacity (for example, reaching 100%), the distribution transformer and line have great safety risks. It should be noted that the preset load rate threshold may vary slightly depending on the specific model and / or age of the hardware equipment of the distribution system, and correspondingly, the maximum load capacity may also vary slightly depending on the specific model and / or age of the hardware equipment of the distribution system.

[0045] Therefore, how to adjust the power of the distribution system to meet the load changes is an urgent problem to be solved.

[0046] Taking into account that the energy storage device has the ability to store and release electric energy, the embodiment of the present application proposes that by setting an energy storage device between two load branches in the load line, the energy storage device can provide electric energy to the load line or absorb the electric energy in the load line, thereby achieving the purpose of adjusting the electric energy of the distribution system so as to meet the load changes.

[0047] In some embodiments, Figure 2 This is a schematic diagram of the structure of the power distribution system provided in some embodiments of the present application, such as Figure 2 As shown, the power distribution system of the embodiment of the present application may include but is not limited to a distribution transformer line 20, a load line 21, and a first energy storage device 22. The output end of the distribution transformer line 20 may be connected to the input end of the load line 21 to transmit electrical energy to the load line 21. The transmission of electrical energy between the distribution transformer line 20 and the load line 21 may include but is not limited to: the distribution transformer line 20 provides electrical energy to the load line 21, or the load line 21 provides electrical energy to the distribution transformer line (i.e., the distribution transformer line 20 absorbs electrical energy from the load line 21).

[0048] In one possible implementation, the power provided by distribution transformer 20 to load line 21 may be power obtained from the power grid. In another possible implementation, the power provided by distribution transformer 20 to load line 21 may be power obtained from power generation equipment; the power generation equipment may include, but is not limited to, at least one of the following: thermal power generation equipment, wind power generation equipment, hydropower generation equipment, solar power generation equipment, and nuclear power generation equipment.

[0049] Of course, the electric energy provided by the distribution transformer 20 to the load line 21 can also be obtained by other means. It should be noted that, for ease of understanding, the following embodiments of this application take the electric energy provided by the distribution transformer 20 to the load line 21 obtained from the power grid as an example to illustrate the relevant contents of the distribution system.

[0050] Exemplarily, the distribution and transformation line may include but is not limited to a distribution transformer; wherein, the input end of the distribution transformer may be connected to the power grid, and the output end of the distribution transformer may be connected to the input end of the load line 21, so as to convert the electric energy transmitted by the power grid into electric energy that can be used by the power user equipment and then transmit it to the load line 21.

[0051] As another example, the distribution and transformation line may include but is not limited to a transmission line; wherein the input end of the transmission line may be connected to the power grid, and the output end of the transmission line may be connected to the input end of the load line 21 to transmit the electric energy transmitted by the power grid to the load line 21.

[0052] The load circuit 21 in the embodiment of the present application can be connected to multiple load branches 210 ( Figure 2 21 ). In the embodiment of the present application, multiple load branches 210 can be connected in parallel to the load line 21 .

[0053] In some embodiments, the load branch 210 involved in the embodiments of the present application may be a household load or an industrial or commercial load, and the embodiments of the present application do not limit this.

[0054] The first energy storage device 22 in the embodiment of the present application can be connected to the connection point (or access point) P between the two load branches 210 in the load line 21 ( Figure 2 In the figure, the first energy storage device 22 is provided at the connection point between the second load branch 210 and the third load branch 210 in the load line 21 as an example, so as to provide electric energy to the load line 21 or absorb electric energy in the load line 21.

[0055] In one 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 called overload), the first energy storage device 22 can provide power to the load line 21 so as to alleviate the load pressure of the line upstream of the access point.

[0056] In some embodiments, the first energy storage device 22 may be configured to provide electrical energy to a load branch 210 located downstream of the access point P in the load line 21 .

[0057] For example, if the capacity of the first energy storage device 22 is relatively large, the first energy storage device 22 can provide power to each load branch 210 located downstream of the access point P, thereby increasing the power supply capacity of the power distribution system and significantly alleviating the load pressure on the lines upstream of the access point P. The lines upstream of the access point P may include, but are not limited to, the lines between the input ends of the distribution transformer line 20 and the load line 21 and the access point P.

[0058] For example, reference Figure 2 As shown, assuming that the current of each load branch 210 is stable at 1 during operation, when the first energy storage device 22 is not connected, the total current at 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 the end current of the load line 21 is 1.

[0059] like Figure 2 As shown, assuming 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 may refer to the output current of the first energy storage device when operating at maximum discharge power), and the first energy storage device 22 is disposed at the connection point between the second load branch 210 and the third load branch 210 in the load line 21, the total current at the input end of the load line 21 is no, the line current between the first load branch 210 and the second load branch 210 is no-1, the line current between the second load branch 210 and the third load branch 210 remains n-2, ..., and the end current of the load line 21 remains 1. It can be seen that by adding the first energy storage device, the current in the line upstream of the access point of the first energy storage device in the load line 21 can be reduced.

[0060] In 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 capability of the first energy storage device 22 is limited), and the distribution line 20 can jointly provide power for the load branches 210 downstream of the access point P with the first energy storage device 22, so as to not only relieve the load pressure of the line upstream of the access point P, but also save the cost of the power distribution system on the basis of increasing the power supply capability of the power distribution system.

[0061] Of course, the distribution line 20 can also provide power for the load branches 210 upstream of the access point P.

[0062] It can be seen that in the embodiment of the present application, on the basis of the distribution line 20 providing power for the load branches 210, the first energy storage device 22 can also provide power for part of the load branches, thereby increasing the power supply capability of the power distribution system and realizing the flexible expansion of the energy storage device for the load line.

[0063] In another possible implementation, when the load rate at the connection point of the first energy storage device 22 is less than a 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, not only to increase the power storage of the first energy storage device 22 for subsequent discharge in heavy load, but also to avoid wasting the power in the power distribution system, thereby improving the power utilization rate of the power distribution system.

[0064] Considering that the load branches 210 can not only consume power as power loads, but also generate power and transmit the power back to the high-voltage side through the load line 21 and the distribution line 20, the first energy storage device 22 in the embodiment of the present application can absorb the power of the load branches 210 in the load line 21 to provide power transfer for power generation in the load branches 210.

[0065] It can be seen that in the embodiment of the present 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.

[0066] It can be seen that in the embodiment of the present 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 improving the reliability of the power distribution system.

[0067] On the basis of the above-mentioned embodiment, in order to facilitate understanding, the following embodiments of the present application take the first energy storage device providing power for the load line as an example to illustrate the related content of the power distribution system.

[0068] Figure 3 This is a schematic diagram of the load changes of the power distribution system provided in the embodiment of the present application. Generally, the load of the power distribution system is not static. It is affected by the load type of the distribution station area, the user's electricity consumption behavior over time, etc. The more common residential load is as follows: Figure 3 The change characteristics shown are large in time fluctuations and have obvious regularity: the load rate in normal time periods can be 45% to 50%, the load rate in low-valley periods is less than 40%, the load rate in peak periods can be more than 80%, and the peak load rate can be 89.1%. It can be seen that the load in the distribution station area has high volatility, which will have a great impact on the power system as a whole during peak periods. The distribution transformer and its downstream low-voltage circuit are in a high-load state at this time. When it exceeds a certain percentage of its maximum load capacity, a failure or safety accident may occur. In the embodiment of the present application, by adding energy storage equipment and utilizing the peak-valley time-shifting characteristics of energy storage, the load peaks and valleys of the load lines can be complementary to maintain the load rate of the distribution system at a certain level. Figure 3 The voltage is below the safety line shown, thereby avoiding as much as possible the tripping, power outage and / or safety accidents caused by heavy overload of the load line during peak power consumption, which is conducive to the reliable operation of the power system.

[0069] Considering that the load branches 210 on the load line 21 are distributed in parallel, the upstream line load is high and the downstream line load is low, and the connected energy storage device can reduce the load splitting effect of the upstream line of the access point, the principle of the optimal access point of the energy storage device can be to make the line load evenly distributed.

[0070] In some embodiments, the current at the connection point (or access point) P in the embodiment of the present application can be greater than the maximum detection current n of the input end of the load line 21. max The difference between the maximum output current o of the first energy storage device 22 and the maximum output current o of the first energy storage device 22 is so that the first energy storage device 22 can be set at a location where the load pressure needs to be reduced (or a location with higher risk). The load pressure of the line upstream of the access point can be reduced to meet the requirements, which is conducive to balancing the line load pressure, thereby improving the stability of the distribution system.

[0071] The maximum output current of the first energy storage device 22 may refer to the output current of the first energy storage device when it is running at the maximum discharge power. max It may refer to the current at the input end of the load circuit when the load of each load branch in the load circuit is maximum.

[0072] For example, referring to the above Figure 2 The power distribution system shown, when n-2 is greater than or equal to n maxIn the case of -o, the first energy storage device may be provided at a connection point between the second load branch and the third load branch.

[0073] In some embodiments, taking into account the load factor of the input end 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 the embodiment of the present application can be the same as the maximum detection current n of the input end of the load line 21. max , minimum detection current n min It is related to the preset maximum current threshold N, so that the load rate requirement of the input end of the load line 21 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. Among them, the preset maximum current threshold N can refer to the maximum overcurrent capacity of the input end of the load line 21. Minimum detection current n min It may refer to the current at the input end of the load circuit when the load of each load branch in the load circuit is minimum.

[0074] On the one hand, considering that the load rate of the input end of the load line 21 is 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, that is, (n max -o) / N needs to be less than or equal to the 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 the embodiment of the present application can be the maximum detection current n max The difference between the target maximum current threshold and the target maximum current threshold may be equal to the product of the preset maximum current threshold N and the preset load rate threshold. For example, the maximum output current o of the first energy storage device 22 may be greater than or equal to (n max -Preset load rate threshold *N).

[0075] On the other hand, considering that load fluctuation has a range and the cost factor of energy storage equipment, the maximum output current o of the first energy storage device 22 should not be too large, that is, the upper limit threshold of the current range of the maximum output current o of the first energy storage device 22 in the embodiment of the present application can be the maximum detection current n max With the minimum detection current n min For example, the maximum output current o of the first energy storage device 22 may be less than (n max -n min ).

[0076] In some embodiments, Figure 4 This is a schematic diagram of the structure of the power distribution system provided in some other embodiments of the present application, such as Figure 4As shown, the power distribution system in the 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 large, the power distribution system in the embodiments of the present application can include multiple first energy storage devices 22 (for the convenience of drawing, Figure 4 In the case that two first energy storage devices 22 are taken as an example, 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 point between two load branches 210 in the load line 21, thereby further increasing the power adjustment capability of the power distribution system, and further relieving the load pressure of the upstream line of the access point of different first energy storage devices, thereby further facilitating the load pressure distribution of the load line.

[0077] 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 access point position and the 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.

[0078] In some embodiments, Figure 5 The structural schematic diagram of the power distribution system provided by another embodiment of the present application is shown in FIG. 6. Figure 5 As shown, the power distribution system in the 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 point between two load branches 210 in the load line 21 to provide power or absorb power in the load line 21.

[0079] It should be understood that the connection point positions of the first energy storage devices 22 in different load lines 21 can be different, and the specific connection point positions can be determined according to the load pressure of the corresponding load line 21. The specific determination method can refer to the related content in the above embodiments, which will not be described here.

[0080] In addition, the number of first energy storage devices 22 in different load lines 21 can be different, and the specific number can be determined according to the load pressure of the corresponding load line 21.

[0081] As can be seen, in the embodiments of the present application, on the basis of the power distribution line 20 providing power for the load branch 210, the power adjustment capability of the power distribution system can be further increased by setting the corresponding first energy storage device 22 on the different load lines 21, and the load pressure of the upstream line of each access point on the different load lines can be further relieved, thereby further facilitating the uniform distribution of the load pressure of the power distribution system.

[0082] Considering that there is no monitoring unit on the low-voltage outgoing line circuit in the distribution system of the traditional distribution station area, the actual operating status, real-time load rate, load rate change, etc. of the low-voltage outgoing line circuit are all unknown. Therefore, in the embodiment of the present application, the load pressure monitoring problem of the low-voltage outgoing line circuit is further considered.

[0083] In some embodiments, the first energy storage device 22 in the embodiments of the present application may include, but is not limited to, a load monitoring circuit to detect the load rate of the connection point and adjust the operating mode of the first energy storage device 22 based on the load rate. The load rate information may be used to indicate the ratio of the real-time load to the maximum load capacity. The operating mode of the first energy storage device 22 may include, but is not limited to, operating state and / or operating power; the operating state of the first energy storage device 22 may include, but is not limited to, charging state, discharging state, or standby state.

[0084] 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 at 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 transmit power to the load line to which it belongs as needed, thereby alleviating the load pressure of the upstream line of the access point and saving the power resources of the first energy storage device.

[0085] For example, when the first energy storage device 22 is in a charging state, the associated load circuit can transmit power to the first energy storage device 22 so that the first energy storage device 22 can store electrical energy. For another example, when the first energy storage device 22 is in a discharging state, the first energy storage device 22 can transmit power to the associated load circuit.

[0086] Figure 6 Schematic diagram of the working state of the energy storage device provided in the embodiment of the present application Figure 1 ,like Figure 6 As shown, the first energy storage device can be adjusted to a charging state when the load rate at the connection point is less than a preset load rate threshold (or light load) and the SOC state of the first energy storage device is less than a first preset SOC threshold, so as to fully utilize the capacity of the corresponding load line 21 and absorb the electrical energy in the load line 21 for electrical energy storage. Exemplarily, the preset load rate threshold may include but is not limited to any value between 65% and 75%, and the first preset SOC threshold may include but is not limited to any value between 92% and 97%. For example, the preset load rate threshold may be 70%, and the first preset SOC threshold may be 95%.

[0087] It should be noted that any preset SOC threshold involved in the implementation of this application (for example, the first preset SOC threshold and / or the second preset SOC threshold) can be adjusted accordingly based on the model, performance, environment, service life and / or health status of the first energy storage device.

[0088] Figure 7 Schematic diagram of the working state of the energy storage device provided in the embodiment of the present application Figure 2 ,like Figure 7 As shown, the first energy storage device can be adjusted to a discharge state when the load rate at the connection point is not less than a preset load rate threshold (or called heavy load) and the SOC state of the first energy storage device is greater than a second preset SOC threshold (i.e., it has a certain power reserve), and can be used as a power output to provide power to the load line, so that the load pressure of the upstream line of the access point of the first energy storage device will be alleviated (the load rate of the downstream line of the access point is determined by the load demand and is not affected). Exemplarily, the second preset SOC threshold may include but is not limited to any value between 5% and 15%. For example, the second preset SOC threshold may be 10%.

[0089] It should be understood that when the load rate at the connection point is less than the preset load rate threshold (i.e., not overloaded) and the SOC state of the first energy storage device is greater than the second preset SOC threshold, that is, the first energy storage device does not need to be charged, and the first energy storage device can be adjusted to a 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, that is, the first energy storage device does not need to be discharged, the first energy storage device can be adjusted to a standby state to continuously monitor the load rate of the load line.

[0090] In addition, the method of detecting the load rate of the connection point through the load monitoring circuit in the first energy storage device 22 can not only assist the first energy storage device in adjusting the working mode, but also facilitate the understanding of the load situation of the load line, data collection and analysis, diagnosis, and prediction (that is, the monitoring data of the load rate can be used as the main data support for the future management and transformation of the distribution station area).

[0091] Taking into account that as the number of load branches on different load lines increases, the load rate of the distribution transformer line becomes higher and higher, and a heavy load situation may exist, therefore, in an embodiment of the present application, a second energy storage device is further provided on the distribution transformer line to alleviate the load pressure of the distribution transformer line.

[0092] In some embodiments, Figure 8 This is a schematic diagram of the structure of the power distribution system provided in some other embodiments of the present application, such as Figure 8As shown, the power distribution system of the embodiment of the present application can further include a second energy storage device 23, wherein the second energy storage device 23 can be connected with the output end of the distribution transformer line 20 to provide electric energy for the load line or absorb electric energy in the distribution transformer line 20. The absorbed electric energy in the distribution transformer line 20 can come from the upstream of the distribution transformer line 20 and / or from the downstream load line.

[0093] 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, the load rate of the load line 21 is normal, which can be less than or equal to the preset load rate. Then the second energy storage device 23 can be set only on the distribution transformer line side. Similarly, according to the foregoing embodiment, the first energy storage device 22 can also be set only on the load line 21 side.

[0094] Exemplarily, the second energy storage device 23 can provide electric energy 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 is beneficial to prolong the service life of the second energy storage device.

[0095] As can be seen, in the case of a certain total load of the distribution transformer line, by means of the second energy storage device as a power supply point connected in parallel with the distribution transformer line, the power supply pressure of the distribution transformer line can be relieved, the load rate of the distribution line can be reduced, and flexible expansion of the energy storage device to the distribution transformer line is realized.

[0096] 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.

[0097] It is considered that the load line is usually long, the current at the input end of the load line (close to the position of 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, the load rate is high, and the load line also has the above-mentioned problems (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).

[0098] In the embodiment of the present application, by means of increasing the second energy storage device at the output end of the distribution transformer line and increasing the first energy storage device on the load line (i.e., combination of distribution transformer line with energy storage and low-voltage outgoing line loop with energy storage), flexible expansion of the energy storage device to the distribution transformer line and the load line is realized, the load pressure at different positions of the power distribution area can be relieved, the load pressure of the power distribution system is balanced, and the stability of the power distribution system is further improved.

[0099] In some embodiments, a metering table can also be arranged between the second energy storage device and the connection point on the distribution line, so that the electricity consumption of the second energy storage device can be metered.

[0100] In some embodiments, a metering table can also be arranged between the second energy storage device and the connection point on the distribution line, so that the electricity consumption of the second energy storage device can be metered.

[0101] In some embodiments, Figure 9 The structural schematic diagram of the power distribution system provided by another embodiment of the present application is shown in the above embodiment, and the structure of the power distribution system is exemplarily introduced and described taking the example of the distribution line 20 including the distribution transformer, and the combination of the distribution line storage and the low-voltage outgoing line loop storage.

[0102] As Figure 9 shown, the power distribution system of the embodiment of the present application can include the distribution 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 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 line 20. Each first energy storage device 22 can be connected with the connection point between the second load branch and the third load branch in the corresponding load line 21. It should be understood that Figure 9 The first energy storage device 22 is arranged between the second load branch and the third load branch in the corresponding load line 21.

[0103] Referring to Figure 9 shown, 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 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.

[0104] As Figure 9As shown, 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, when 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 end current of the load line 21 is still 1.

[0105] In some embodiments, the first energy storage device 22 and the second energy storage device 23 may be the same type of energy storage device, which may include but is not limited to electrochemical energy storage, which may include but is not limited to lithium-ion batteries and sodium-ion batteries.

[0106] In some embodiments, the energy storage scale of the second energy storage device 23 may be greater than the energy storage scale of the first energy storage device 22 , wherein the energy storage scale may include but is not limited to: maximum storable power and / or maximum charge and discharge power.

[0107] It should be understood that the energy storage capacity of any energy storage device in the embodiments of the present application can be determined according to the preset distribution and transformation ratio and the load rate fluctuation of the target line to which the energy storage device is connected, so that the load peaks and valleys of the target line can be complementary.

[0108] It can be seen that by adding the first energy storage device and the second energy storage device, the current in the distribution transformer line and the upstream line of the access point of the first energy storage device in each load line 21 can be reduced, which is conducive to alleviating the load pressure at different locations in the distribution station area and achieving the effect of balancing the load pressure of the distribution system.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A power distribution system, characterized in that: The power distribution system includes a distribution transformer line, a load line, and a first energy storage device, wherein the output end of the distribution transformer line is connected to the input end of the load line to transmit electric energy to 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 to the load line or absorb electric energy in the load line; The first energy storage device includes 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.

2. The power distribution system according to claim 1, characterized in that The first energy storage device is configured to provide electrical energy to a load branch in the load circuit that is located downstream of the connection point.

3. The power distribution system according to claim 1, wherein: The current at 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.

4. The power distribution system according to claim 3, characterized in that: 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.

5. The power distribution system according to claim 4, characterized in that: The upper limit threshold of the current range is the difference between the maximum detection current and the minimum detection current; the lower limit 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.

6. The power distribution system according to any one of claims 1 to 5, characterized in that: The power distribution system includes 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 respectively connected to a connection point between two of the load branches in the load circuit.

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

8. The power distribution system according to any one of claims 1 to 5, characterized in that: A meter is provided between the first energy storage device and the connection point.

9. The power distribution system according to any one of claims 1 to 5, characterized in that: The power distribution system further includes a second energy storage device, wherein the second energy storage device is connected to the output end of the distribution transformer line to provide electrical energy to the load line or absorb electrical energy in the distribution transformer line.

10. The power distribution system according to any one of claims 1 to 5, characterized in that: The distribution and transformation line includes a distribution transformer; wherein the input end of the distribution transformer is connected to the power grid, and the output end of the distribution transformer is connected to the input end of the load line.

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