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-references

[0002] This application incorporates Chinese Patent Application No. 2024208415204, filed on April 22, 2024, entitled “Power Distribution System”, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of power distribution technology, and in particular to a power distribution system. Background Technology

[0004] With social development, electricity demand continues to grow, placing increasing demands on the power supply capacity (or carrying capacity or load capacity) of power distribution systems. However, once constructed, power distribution systems have an upper limit on their power supply capacity, and there may be situations where the power supply capacity of the power distribution system cannot meet the electricity demand.

[0005] Therefore, how to adjust the electrical energy of the power distribution system is an urgent problem to be solved.

[0006] Summary of the Invention

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

[0008] In a first aspect, this application provides a power distribution system, which includes a distribution transformer line, a load line, and a first energy storage device. 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 from the load line.

[0009] The power distribution system of this application embodiment, 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 not only adjusts the power of the power distribution system to meet load changes, but also greatly alleviates the load pressure on the upstream line 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 to a load branch located downstream of the connection point in the load line, thereby increasing the power supply capacity of the power distribution system and realizing flexible capacity expansion of the load line by the energy storage device.

[0011] In some embodiments, the current at the connection point is greater than the difference between the maximum detected current at the input end of the load line and the maximum output current of the first energy storage device. This allows the first energy storage device to be installed at locations where load pressure needs to be reduced. This reduces the load pressure on the upstream line at the connection point to meet the requirements, which helps to balance the line load pressure and thus improves 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 at the input of the load line, so as to meet the load rate requirements at the input of the load line while saving the cost of the first energy storage device, thereby improving the stability of the power distribution system.

[0013] In some embodiments, the upper limit threshold of the current range is the difference between the maximum detected current and the minimum detected current; the lower limit threshold of the current range is the difference between the maximum detected 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 this embodiment, by setting the lower limit of the current range as the difference between the maximum detected current and the target maximum current threshold, the load rate at the input of the load line can be made less than or equal to a preset load rate threshold, thereby improving the stability of the load line. By setting the upper limit of the current range of the maximum output current of the first energy storage device as the difference between the maximum detected current and the minimum detected current, the cost of the first energy storage device can be saved.

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

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

[0017] In this embodiment of the application, based on the distribution transformer line providing power to the load branch, the power adjustment capability of the power distribution system can be further increased by setting up corresponding first energy storage devices on different load lines. This can also further alleviate the load pressure on the upstream lines of each access point on different load lines, thereby further contributing to the uniform distribution of load pressure in the power distribution system.

[0018] 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 operating 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 on demand, thereby relieving the load pressure on the upstream line of the access point and saving the power resources of the first energy storage device.

[0019] In some embodiments, a meter is provided between the first energy storage device and the connection point to facilitate the detection of power changes in the first energy storage device.

[0020] 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 terminal of the distribution transformer line to provide power to the load line or absorb power from the distribution transformer line.

[0021] In this embodiment of the application, by adding a second energy storage device at the output end of the distribution transformer line and a first energy storage device on the load line, the energy storage device can flexibly expand the capacity of the distribution transformer line and the load line. This can alleviate the load pressure at different locations in the distribution transformer area, which is conducive to balancing the load pressure of the power distribution system and further improving the stability of the power distribution system.

[0022] In some embodiments, the distribution 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 electrical energy transmitted by the power grid into electrical energy that can be used by the user equipment and then transmit it to the load line.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1 is a schematic diagram of the power distribution system structure corresponding to the power distribution area provided in the embodiment of this application;

[0026] Figure 2 is a schematic diagram of the power distribution system provided in some embodiments of this application;

[0027] Figure 3 is a schematic diagram of the load change of the power distribution system provided in the embodiment of this application;

[0028] Figure 4 is a schematic diagram of the power distribution system provided in some other embodiments of this application;

[0029] Figure 5 is a schematic diagram of the power distribution system provided in some other embodiments of this application;

[0030] Figure 6 is a schematic diagram of the working state of the energy storage device provided in the embodiment of this application;

[0031] Figure 7 is a schematic diagram of the working state of the energy storage device provided in the embodiment of this application;

[0032] Figure 8 is a schematic diagram of the power distribution system provided in some other embodiments of this application;

[0033] Figure 9 is a schematic diagram of the power distribution system provided in some other embodiments of this application. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed 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 this application can be the power distribution system corresponding to the power distribution substation; of course, it can also be the power distribution system corresponding to other scenarios.

[0038] For ease of explanation, the following embodiments use the power distribution system corresponding to a power distribution substation as an example. It should be understood that when the power distribution system in this embodiment is used for other scenarios, the implementation principle and technical effects are similar.

[0039] For ease of understanding, the relevant content of the distribution radio area will be introduced and explained first in this embodiment of the application.

[0040] Power systems typically transmit electrical energy from power plants to user equipment locations via ultra-high voltage (UHV), high voltage (HV), and / or medium voltage (MTV) transmission lines. Upon arrival at the user location, transformers at various levels gradually reduce the voltage of the electrical energy in the lines from UHV to HV to MTV. Finally, distribution transformers convert the medium voltage electricity in the medium voltage transmission lines into low voltage electrical energy that can be used by the user equipment. This low voltage electrical energy is then transmitted to each electricity demander (i.e., user equipment) via low voltage outgoing circuits (or load lines).

[0041] Generally, a distribution transformer area refers to a low-voltage power transmission network consisting of a distribution transformer and all its downstream low-voltage outgoing circuits. 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 low-voltage outgoing circuits it has downstream; conversely, the smaller the capacity of the distribution transformer, the fewer low-voltage outgoing circuits it has downstream.

[0042] Figure 1 is a schematic diagram of the power distribution system structure corresponding to the power distribution substation provided in this application embodiment. As shown in Figure 1, the input terminal of the power distribution transformer 10 can be connected to the medium-voltage transmission line 12 through the ring main unit 11, and the output terminal of the power distribution transformer 10 can be connected to the input terminal of m parallel low-voltage outgoing circuits 13. Each low-voltage outgoing circuit 13 is connected to n parallel loads (or load branches). Wherein, m and n are both integers greater than 1.

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

[0044] For ease of understanding, the following section uses the current on the first low-voltage outgoing circuit 13 as an example. The currents on the other low-voltage outgoing circuits 13 are similar and will not be described again here.

[0045] Assuming the current of each load is stable at 1 during operation, the total current at the input terminal 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 end load is 1.

[0046] A power system is a demand-response system (meaning that the power system transmits the amount of electrical energy required by the load, and the corresponding power plants at the front end produce that amount of electrical energy). The same applies to the distribution system of a distribution substation. The more loads in the distribution system, and the more energy each load requires, the more energy the distribution transformers convert, and the more energy the low-voltage outgoing circuits transmit.

[0047] However, once the power distribution system of a distribution substation is completed, its hardware (e.g., distribution transformers and low-voltage outgoing circuits) remains fixed, possessing its own upper limit of carrying capacity, which is the maximum load capacity of the distribution substation. Load, on the other hand, is variable and continuously increasing. A power distribution system initially designed based on experience may, after a certain period, experience situations where the load exceeds the maximum operating capacity or even the maximum carrying capacity of the distribution transformer due to load growth or significant fluctuations. When the load rate (the ratio of real-time load to maximum carrying capacity) remains above the preset load rate threshold (e.g., 70%) for an extended period, both the distribution transformer and low-voltage outgoing circuits face high safety and reliability risks. Furthermore, when the load rate exceeds its maximum carrying capacity (e.g., reaching 100%), the distribution transformer and lines face significant safety risks. It should be noted that the preset load rate threshold may vary slightly depending on the specific model and / or service life of the hardware equipment in the power distribution system; correspondingly, the maximum carrying capacity may also vary slightly depending on the specific model and / or service life of the hardware equipment in the power distribution system.

[0048] Therefore, how to adjust the electrical energy of the power distribution system to meet load changes is an urgent problem to be solved.

[0049] Considering that energy storage devices have the ability to store and release electrical energy, this application proposes to set up an energy storage device between two load branches in the load line. The energy storage device can provide electrical energy to the load line or absorb electrical energy in the load line, thereby achieving the purpose of adjusting the power distribution system so as to meet load changes.

[0050] In some embodiments, FIG2 is a schematic diagram of the power distribution system provided in some embodiments of this application. As shown in FIG2, the power distribution system of this application embodiment 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 terminal of the distribution transformer line 20 may be connected to the input terminal of the load line 21 to transmit electrical energy. 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 providing electrical energy to the load line 21, or the load line 21 providing electrical energy to the distribution transformer line (i.e., the distribution transformer line 20 absorbing electrical energy from the load line 21).

[0051] In one possible implementation, the electrical energy provided by the distribution transformer line 20 to the load line 21 can be electrical energy obtained from the power grid. In another possible implementation, the electrical energy provided by the distribution transformer line 20 to the load line 21 can be electrical energy obtained from power generation equipment; wherein, 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.

[0052] Of course, the electrical energy provided by the distribution transformer line 20 to the load line 21 can also be obtained through other means. It should be noted that, for ease of understanding, the following embodiments of this application use the example of the electrical energy provided by the distribution transformer line 20 to the load line 21 obtained from the power grid to illustrate the relevant content of the power distribution system.

[0053] For example, the distribution line may include, but is not limited to, the 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 electrical energy transmitted by the power grid into electrical energy that can be used by the user equipment and then transmit it to the load line 21.

[0054] As another example, the distribution transformer line may include, but is not limited to, transmission lines; 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, so as to transmit the electrical energy transmitted by the power grid to the load line 21.

[0055] In this embodiment, the load line 21 can be connected to multiple load branches 210 (shown as n in Figure 2) to deliver electrical energy to the user equipment (or electrical load) in each load branch 210. For example, in this embodiment, the multiple load branches 210 can be connected in parallel to the load line 21.

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

[0057] In this embodiment of the application, the first energy storage device 22 can be connected to the connection point (or access point) P between two load branches 210 in the load line 21 (Figure 2 shows the first energy storage device 22 being set at the connection point between the second load branch 210 and the third load branch 210 in the load line 21) to provide power to the load line 21 or absorb power from the load line 21.

[0058] In one possible implementation, if the load rate at the connection point of the first energy storage device 22 is not less than a preset load rate threshold (or heavy load), the first energy storage device 22 can provide power to the load line 21 so as to alleviate the load pressure on the upstream line of the connection point.

[0059] In some embodiments, the first energy storage device 22 may be configured to provide power to the load branch 210 located 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 to each load branch 210 located downstream of the access point P, which not only increases the power supply capacity of the power distribution system, but also greatly alleviates the load pressure on the upstream lines of the access point P. The upstream lines of the access point P may include, but are not limited to, the lines between the input terminals of the distribution transformer line 20 and the load line 21 and the access point P.

[0061] For example, referring to Figure 2, 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.

[0062] As shown in Figure 2, assuming the maximum output current of the first energy storage device 22 is 0 (the maximum output current of the first energy storage device 22 can refer to the output current when the first energy storage device is operating at its maximum discharge power), and the first energy storage device 22 is located 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 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 is still n-2, ..., and the current at the end of the load line 21 is still 1. It can be seen that by adding the first energy storage device, the current in the line upstream of the connection point of the first energy storage device in the load line 21 can be reduced.

[0063] As another example, considering the cost 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). The distribution transformer line 20 can work with the first energy storage device 22 to provide power to each load branch 210 located downstream of the access point P. In this way, the power supply capacity of the power distribution system is increased, which can not only alleviate the load pressure of the upstream line of the access point P, but also save the cost of the power distribution system.

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

[0065] As can be seen, in this embodiment of the application, in addition to the distribution transformer line 20 providing power to the load branch 210, the first energy storage device 22 can also provide power to some load branches, thereby increasing the power supply capacity of the power distribution system and realizing the 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 light load, or low electricity consumption), the first energy storage device 22 can absorb the electrical energy in the load line 21. This not only increases the electrical energy storage capacity of the first energy storage device 22 so that it can be discharged later under heavy load, but also does not waste the electrical energy in the power distribution system, which is conducive to improving the power utilization rate of the power distribution system.

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

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

[0069] As can be seen, in this embodiment of the application, by setting a first energy storage device between two load branches in the load line, the first energy storage device can provide power to the load line or absorb power in the load line. This not only adjusts the power of the power distribution system to meet load changes, but also greatly alleviates the load pressure on the upstream line of the access point, thereby improving the reliability of the power distribution system.

[0070] Based on the above embodiments, for ease of understanding, the following embodiments of this application take the first energy storage device providing power to the load line as an example to illustrate the relevant contents 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, FIG4 is a schematic diagram of the power distribution system provided in other embodiments of this application. As shown in FIG4, the power distribution system of this application embodiment may include multiple load branches. When the load pressure of multiple connection points in the load line 21 is large, the power distribution system of this application embodiment may include multiple first energy storage devices 22 (for ease of drawing, FIG4 shows two first energy storage devices 22 as an example, 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 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 alleviating the load pressure of the upstream line of the access point of different first energy storage devices, thereby further facilitating the balancing of the load pressure of the load line.

[0080] It should be noted that when multiple connection points in the load line 21 are equipped with corresponding second energy storage devices, the access point location and maximum output current of each second energy storage device can be referred to the relevant content in the above embodiments, and will not be repeated here.

[0081] In some embodiments, FIG5 is a schematic diagram of the power distribution system provided in other embodiments of this application. As shown in FIG5, the power distribution system in the embodiments of this application may include multiple load lines 21 and multiple first energy storage devices 22. At least one first energy storage device 22 may be connected to the connection point between two load branches 210 in the load line 21 respectively, so as to provide power to the corresponding load line 21 or absorb the power in the load line 21.

[0082] It should be understood that the connection point of the first energy storage device 22 in different load lines 21 may be different. The specific connection point can be determined according to the load pressure of the corresponding load line 21. The specific determination method can refer to the relevant content in the above embodiment, which will not be repeated here.

[0083] 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.

[0084] As can be seen, in this embodiment of the application, on the basis of the distribution transformer line 20 providing power to the load branch 210, the power adjustment capability of the power distribution system can be further increased by setting up corresponding first energy storage devices 22 on different load lines 21, and the load pressure of the upstream lines at each access point on different load lines can be further alleviated, thereby further contributing to the uniform distribution of load pressure in the power distribution system.

[0085] Considering that there are no monitoring units on the low-voltage outgoing circuits in the traditional power distribution system of the distribution substation, the actual operating status, real-time load rate, and load rate changes of the low-voltage outgoing circuits are all unknown. Therefore, in this embodiment, the load pressure monitoring problem of the low-voltage outgoing circuits is further considered.

[0086] In some embodiments, the first energy storage device 22 in this 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 according to the load rate. The load rate information can be used to indicate the ratio of real-time load to maximum carrying 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.

[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 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 on demand, thereby relieving the load pressure on the upstream line of the access point and saving the power resources of the first energy storage device.

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

[0089] Figure 6 is a schematic diagram of the working state of the energy storage device provided in this application embodiment. As shown in Figure 6, 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 make full use of the capacity of the corresponding load line 21 and absorb the electrical energy in the load line 21 for energy storage. For example, the preset load rate threshold can be any value from 65% to 75%, and the first preset SOC threshold can be any value from 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 involved in the implementation of this application (e.g., 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.

[0091] Figure 7 is a schematic diagram of the working state of the energy storage device provided in this embodiment of the application. As shown in Figure 7, 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 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 amount of energy reserve). This allows it to supply power to the load line, thereby alleviating the load pressure on the upstream line of the first energy storage device's connection point (the load rate of the downstream line is determined by the load demand and is unaffected). For example, the second preset SOC threshold can be any value from 5% to 15%. For instance, 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 a preset load rate threshold (i.e., not under heavy load) and the SOC state of the first energy storage device is greater than a second preset SOC threshold, the first energy storage device does not need to be charged and can be adjusted to standby mode to continuously monitor the load rate of the load line. When the load rate at the connection point is not less than a preset load rate threshold and the SOC state of the first energy storage device is not greater than a second preset SOC threshold, the first energy storage device does not need to be discharged and can be adjusted to standby mode to continuously monitor the load rate of the load line.

[0093] In addition, by detecting the load rate of the connection point through the load monitoring circuit in the first energy storage device 22, it can not only help the first energy storage device adjust its working mode, but also help to understand the load status of the load line, collect and analyze data, diagnose and predict (that is, the load rate monitoring data can serve 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 transformer lines becomes higher and higher, and there may be heavy load situations, this embodiment of the application further alleviates the load pressure of the distribution transformer lines by setting a second energy storage device on the distribution transformer lines.

[0095] In some embodiments, FIG8 is a schematic diagram of the power distribution system provided in other embodiments of this application. As shown in FIG8, the power distribution system of this application embodiment may further include a second energy storage device 23, wherein the second energy storage device 23 may be connected to the output terminal of the distribution transformer line 20 to provide power to the load line or absorb power from the distribution transformer line 20. The absorbed power from the distribution transformer line 20 may come from the upstream of the distribution transformer line 20 and / or from 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 on the distribution transformer line side is too high, it can be selected to be greater than a preset load rate threshold. If the load rate of the load line 21 is normal, it can be selected to be less than or equal to the preset load rate. In this case, only the second energy storage device 23 can be set on the distribution transformer line side. Similarly, according to the aforementioned embodiments, only the first energy storage device 22 can be set on the load line 21 side.

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

[0098] It is evident that, given a fixed total load on the distribution transformer line, using a second energy storage device as a power source connected in parallel with the distribution transformer line can alleviate the power supply pressure on the distribution transformer line, reduce the load rate of the distribution line, and realize the flexible capacity expansion of the distribution transformer line by the energy storage device.

[0099] It should be noted that the load pressure on the distribution transformer line can be alleviated simply by setting up an energy storage device at the output end of the distribution transformer line 20.

[0100] Considering that load lines are usually quite 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. Furthermore, the rated current of the load line is designed to be relatively small (usually, when there are m load branches on 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 and load rate of the distribution transformer line are high. At the same time, 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 also the possibility of adding or adjusting load branches, which may further worsen the line load rate).

[0101] In this embodiment of the 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 (i.e., combining distribution transformer line energy storage with low-voltage outgoing circuit energy storage), the flexible capacity expansion of the energy storage device for the distribution transformer line and the load line is realized. This can alleviate the load pressure at different locations in the distribution transformer area, which is conducive to balancing the load pressure of the power distribution system and further improving the stability of the power distribution system.

[0102] In some embodiments, a meter may be provided between the first energy storage device and the connection point on the load line in this application embodiment so as to measure the power consumption of the first energy storage device.

[0103] In some embodiments, a meter may also be installed between the second energy storage device and the connection point on the distribution transformer line in this application embodiment, so as to measure the power consumption of the second energy storage device.

[0104] In some embodiments, FIG9 is a schematic diagram of the power distribution system provided in other embodiments of this application. Based on the above embodiments, this application takes the distribution transformer line 20 including the distribution transformer and the combination of distribution transformer line distribution and storage with low voltage outgoing circuit distribution and storage as an example to illustrate the structure of the power distribution system.

[0105] As shown in Figure 9, the power distribution system of this embodiment may include a distribution transformer line 20, m load lines, multiple first energy storage devices 22, and second energy storage devices 23. The input end of the distribution transformer line 20 can be connected to the medium-voltage transmission line 12 via a ring main unit 11, and the second energy storage devices 23 can be connected to the output end of the distribution transformer line 20. Each first energy storage device 22 can be connected to the connection point between two load branches in the corresponding load line 21. It should be understood that Figure 9 illustrates an example where the first energy storage devices 22 are respectively located at the connection points between the second and third load branches in the corresponding load line 21.

[0106] Referring to Figure 9, assuming that the stable current of each load branch in each load line 21 is 1 during operation, and without the first energy storage device 22 and the second energy storage device 23 connected, the total current at the input end of each load line 21 is n, the total current at 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 current at the end of the load line 21 is 1.

[0107] As shown in Figure 9, assuming the maximum output current of the first energy storage device 22 is o1 and the maximum output current of the second energy storage device 23 is o2, and the second energy storage device 23 is connected to the output terminal of the distribution transformer line 20, and the first energy storage device 22 is set 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 terminal of the distribution transformer line is (n-o1)*m-o2, the total current at the input terminal 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.

[0108] 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. The energy storage device 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.

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

[0110] It should be understood that the energy storage capacity of any energy storage device in the embodiments of this 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 as to enable the load peak and valley of the target line to complement each other.

[0111] It is evident that by adding the first energy storage device and the second energy storage device, the current in the distribution transformer line and the line upstream of the access point of the first energy storage device in each load line 21 can be reduced, which helps to alleviate the load pressure at different locations in the distribution transformer area and achieve 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 this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This 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 includes a distribution transformer line, a load line, and a first energy storage device. 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 from the load line.

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

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

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

5. The power distribution system according to claim 4, wherein, The upper limit threshold of the current range is the difference between the maximum detected current and the minimum detected current; the lower limit threshold of the current range is the difference between the maximum detected 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 1-5, wherein, The power distribution system includes multiple first energy storage devices and multiple load branches, with at least one first energy storage device connected to a connection point between two load branches in the load line.

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

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

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

10. The power distribution system according to any one of claims 1-9, wherein, The power distribution system also includes a second energy storage device, which is connected to the output end of the distribution transformer line to provide power to the load line or absorb power from the distribution transformer line.

11. The power distribution system according to any one of claims 1-10, wherein, The distribution 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.

Images