Zero-carbon power supply station power distribution system for source network load storage and charging

Abstract

The invention relates to the technical field of power distribution, and discloses a zero-carbon power supply station power distribution system for source network load storage and charging, which comprises an alternating-current power grid, a charging device, a direct-current power distribution network and an electric quantity management system, the two alternating-current power grids are connected with the direct-current power distribution network through the charging device; the electric quantity management system is connected with the AC power grid and the DC power distribution network. The direct-current power distribution network is provided with direct-current buses of different voltage grades, and power is supplied to different direct-current loads through the direct-current buses of different voltage grades. The electric quantity management system is used for collecting and monitoring electric parameters of the direct-current power distribution network and the alternating-current power grid, supplying power to the direct-current power distribution network by the alternating-current power grid through the charging device when monitoring that the power generation of the direct-current power distribution network is insufficient, and supplying power to the direct-current power distribution network by the charging device when monitoring that the power generation of the direct-current power distribution network is excessive. And the direct-current power distribution network supplies power to the alternating-current power grid through the charging device. The power supply stability or flexibility of the zero-carbon power supply station is ensured, and the energy management is more efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution, and in particular to a zero-carbon power distribution system for source, grid, load, storage and charging. Background Art

[0002] With the continuous advancement of the construction of new power systems, more and more new energy sources are gradually entering people's daily lives. In many scenarios such as new energy vehicle charging and swapping stations, highway service areas, urban central commercial complexes and public parking lots, industrial parks, as well as household and commercial users, the integrated photovoltaic storage and charging system has shown great application potential.

[0003] At present, with the continuous advancement of the construction of zero-carbon power stations, the storage and charging DC distribution system composed of photovoltaic power generation components, energy storage components and charging pile components is being continuously promoted in power supply institutions such as power stations. In the current storage and charging distribution system, the load and DC charging pile are directly connected to the DC bus and powered by DC. Although this power supply method reduces the loss of electric energy compared to the AC distribution scheme of traditional new energy, due to the volatility and instability of photovoltaic and wind power generation in zero-carbon power stations, unstable power output may occur during power supply. Summary of the invention

[0004] In view of the problem of unstable power output in the power supply of zero-carbon power stations in the prior art, the present invention provides a zero-carbon power station distribution system with source, grid, load, storage and charging, which can realize the bidirectional flow of electric energy between the DC distribution network and the AC grid, ensure the stable operation of the DC load, and ensure the stability or flexibility of the DC load power supply. The specific technical solution is as follows:

[0005] A zero-carbon power distribution system with source-grid-load-storage-charge, comprising an AC power grid, a charging device, a DC distribution network and a power management system; the two AC power grids are connected to the DC distribution network through the charging device; the power management system is connected to the AC power grid and the DC distribution network respectively; the DC distribution network is provided with DC buses of different voltage levels, and supplies power to different DC loads through the DC buses of different voltage levels;

[0006] The power management system is used to monitor the electrical parameters of the DC distribution network and the AC power grid. When it is monitored that the DC distribution network is under-generated, the AC power grid supplies power to the DC distribution network through the charging device. When it is monitored that the DC distribution network is over-generated, the DC distribution network supplies power to the AC power grid through the charging device.

[0007] Preferably, the power management system is also used to monitor the carbon emissions of each link in the AC power grid and the DC distribution network in real time.

[0008] Preferably, a zero-carbon power supply distribution system with source-grid-load-storage charging also includes an electric energy meter; the electric energy meter is arranged in the branches of the AC power grid and the DC distribution network, and is used to measure the electric energy of each branch of the system and transmit the measurement data to the power management system.

[0009] Preferably, the DC distribution network includes a photovoltaic generator set, a wind generator set, a transformer, a primary DC bus, a secondary DC bus, a charging pile and a secondary DC load; the photovoltaic generator set and the wind generator set are both connected to the primary DC bus; the primary DC bus is directly connected to the charging pile; the primary DC bus is also directly connected to the secondary DC bus through the transformer; the secondary DC bus is connected to the secondary DC load.

[0010] Preferably, the charging pile is a bidirectional DC charging pile.

[0011] Preferably, the DC distribution network further includes an energy storage device and an energy storage converter, and the energy storage device is connected to the primary DC bus through the energy storage converter.

[0012] Preferably, the AC power grid includes an AC load and an AC bus; the AC load is connected to the AC bus; and the AC bus is connected to the primary DC bus through the charging device.

[0013] Preferably, when the DC distribution network generates insufficient power, the AC grid supplies power to the DC distribution network through the charging device, and when the DC distribution network generates excess power, the DC distribution network supplies power to the AC grid through the charging device, specifically including:

[0014] When the voltage of the primary DC bus is in the first preset interval, it is determined that the photovoltaic and wind power generation is sufficient, and the energy storage device is started to charge until it is fully charged;

[0015] When the voltage of the primary DC bus is in the second preset interval, the charging pile and the low-voltage DC load are powered, and the charging state of the energy storage device is turned off;

[0016] When the voltage of the primary DC bus is within a third preset interval, it is determined that photovoltaic and wind power generation is insufficient, the discharge state of the energy storage device is turned on, and the energy storage device supplies power to the DC distribution network;

[0017] When the voltage of the primary DC bus is within a fourth preset interval, it is determined that photovoltaic power generation, wind power generation and energy storage are insufficient, and the discharge state of the charging pile is turned on;

[0018] When the voltage of the primary DC bus is lower than a preset threshold, the rectification function of the charging device is turned on, and the AC power grid supplies power to the DC distribution network.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] A zero-carbon power distribution system with source-grid-load-storage charging of the present invention is achieved by connecting the AC power grid to the DC distribution network through the charging device; the DC distribution network is provided with DC buses of different voltage levels, and supplies power to different DC loads through DC buses of different voltage levels. The charging device of the present invention can realize the bidirectional flow of DC / AC electric energy, and can supply power from the AC power grid to the DC distribution network, and from the DC distribution network to the AC power grid. By real-time monitoring of the electrical parameters of the DC distribution network and the AC power grid through the power management system, the AC power grid can be used for power supply when the distributed new energy power generation is insufficient or unstable, ensuring the stable operation of the DC load; it can also transmit excess electric energy to the AC power grid when the distributed new energy power generation is excessive, ensuring the stability or flexibility of the DC load power supply, making energy management more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0022] Figure 1 This is a schematic diagram of a zero-carbon power distribution system with source, grid, load, storage and charging according to the present invention.

[0023] Figure 2-Figure 5 It is a schematic diagram of various operating modes of a zero-carbon power distribution system of the source-grid-load-storage charging of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] See the following examples Figures 1 to 5 .

[0029] The embodiment of the present application provides a zero-carbon power distribution system with source-grid-load-storage-charge, including an AC power grid, a charging device, a DC distribution network and an electric power management system; the two AC power grids are connected to the DC distribution network through the charging device; the electric power management system is connected to the AC power grid and the DC distribution network respectively; the DC distribution network is provided with DC buses of different voltage levels, and supplies power to different DC loads through DC buses of different voltage levels;

[0030] The power management system is used to monitor the electrical parameters of the DC distribution network and the AC power grid. When it is monitored that the DC distribution network is under-generated, the AC power grid supplies power to the DC distribution network through the charging device. When it is monitored that the DC distribution network is over-generated, the DC distribution network supplies power to the AC power grid through the charging device.

[0031] In this embodiment, a DC distribution network is connected between two AC power grids (two substations), and DC busbars with different voltage levels are set in the DC distribution network. For example, 750V and 220V DC voltage levels are set. Wind turbines, photovoltaic generators and DC bidirectional charging piles are connected in parallel on the DC 750V busbar, and the low-voltage side of the DC 220V busbar supplies power to DC loads such as lighting.

[0032] It should be noted that the power management system includes a coordination controller, which is used for switching the AC and DC microgrid operation modes and energy management, organically coordinating various elements to achieve regional efficient and economical operation.

[0033] The charging device of the present invention can realize the bidirectional flow of DC / AC electric energy, and can supply power from the AC power grid to the DC distribution network, and can also supply power from the DC distribution network to the AC power grid. When the distributed new energy power generation is insufficient or unstable, the AC power grid can be used to supply power to ensure the stable operation of the DC load; when the distributed new energy power generation is excessive, the excess electric energy can be transmitted to the AC power grid, ensuring the stability or flexibility of the DC load power supply, making energy management more efficient. At the same time, by setting DC buses of different voltage levels in the DC distribution network, loads of different voltage levels or charging piles and other equipment are used for adaptive charging and discharging. The low-voltage DC load is directly connected to the low-voltage side bus to draw power, and the charging pile can be directly connected to the high-voltage side bus to draw power, thereby improving the charging efficiency of electric vehicles, which is not only safe but also efficient.

[0034] Specifically, in a preferred implementation manner of the present application, the power management system is also used to monitor the carbon emissions of each link in the AC power grid and the DC distribution network in real time.

[0035] Specifically, a zero-carbon power supply distribution system with source-grid-load-storage charging also includes an electric energy meter; the electric energy meter is arranged in the branches of the AC power grid and the DC distribution network, and is used to measure the electric energy of each branch of the system and transmit the measurement data to the power management system.

[0036] In the specific implementation, each converter (transformer, energy storage converter, etc.) of the AC power grid and DC distribution network is connected to the power management system through RS485 communication lines. The power management system monitoring system performs carbon flow analysis and monitoring on each link, and receives the power data of each branch of the system measured by the power meter, calculates and monitors the carbon emissions of each link in real time, and adopts the system carbon emission calculation method based on the emission factor method. By obtaining the dynamic carbon emission factor of the power grid in the area where the system is located and the instantaneous operation data of the user system, the user's dynamic carbon emission factor is calculated, and the total carbon emissions within a day are calculated according to the following formula. The total carbon emissions are calculated as follows:

[0037]

[0038] Among them, e C is the instantaneous carbon dioxide emission factor of the system; E k,t is the total instantaneous system power of user k at time t; is the system average carbon dioxide emission factor within time T; Q i The power generation of different power sources.

[0039] Specifically, the DC distribution network includes a photovoltaic generator set, a wind generator set, a transformer, a primary DC bus, a secondary DC bus, a charging pile and a secondary DC load; the photovoltaic generator set and the wind generator set are both connected to the primary DC bus; the primary DC bus is directly connected to the charging pile; the primary DC bus is directly connected to the secondary DC bus through the transformer; the secondary DC bus is connected to the secondary DC load.

[0040] The photovoltaic power generation group includes N photovoltaic power generation groups, photovoltaic power generation 1 to photovoltaic power generation N. Each group is connected to a transformer and then to a primary DC bus (high-voltage bus side).

[0041] By setting different voltage levels of the DC distribution network to adapt power supply to different loads, the flexibility of power supply is improved and the power supply efficiency is guaranteed. For example, the charging pile can be directly connected to the primary DC bus (high-voltage bus side), which can improve the fast high-voltage DC charging for electric vehicles and improve the charging efficiency. The charging pile in this embodiment is a bidirectional DC charging pile, which can realize the charging and discharging functions of electric vehicles and distribution networks by utilizing the bidirectional power supply capability.

[0042] In this embodiment, the photovoltaic converter of the photovoltaic generator set has an MPPT function, which can adjust the working point of the solar panel in real time so that it always operates at the maximum power point. In this way, solar energy can be utilized to the maximum extent and the power generation efficiency of the photovoltaic system can be improved.

[0043] Specifically, the DC distribution network further includes an energy storage device and an energy storage converter, and the energy storage device is connected to the primary DC bus through the energy storage converter. The energy storage device can be a battery pack, which serves as a backup power source. When the photovoltaic and wind power generation is insufficient or the system power demand increases, the battery pack will release the previously stored electric energy to supplement the power supply for the DC bus.

[0044] The energy storage device (battery pack) is connected to the primary DC bus through the energy storage converter. It can release the stored electric energy to provide stable power supplement for the DC bus when the photovoltaic power generation is insufficient or the system power demand increases. This helps to balance the supply and demand of electricity, reduce grid fluctuations, and improve the stability of the entire system. As a backup power source, the battery pack can provide power support in an emergency and ensure the continuous power supply of critical loads, thereby improving the reliability of the system. By increasing the energy storage capacity or adjusting the parameters of the energy storage converter, the power supply capacity of the system can be flexibly adjusted.

[0045] Specifically, the AC power grid includes an AC load and an AC bus; the AC load is connected to the AC bus; the AC bus is connected to the primary DC bus through the charging device. The AC bus is connected to the primary DC bus through the charging device, so that the AC load can be easily connected to the power grid. The design of connecting the AC power grid to the new energy DC distribution network not only retains the flexibility of the AC power grid, but also makes full use of the efficiency and stability of the DC power grid. Through the connection of the charging device to the primary DC bus, the interconnection between the DC and AC power grids is realized, and the flexibility of power transmission and distribution is improved.

[0046] Specifically, when it is monitored that the DC distribution network generates insufficient power, the AC network supplies power to the DC distribution network through the charging device; when it is monitored that the DC distribution network generates excess power, the DC distribution network supplies power to the AC network through the charging device, specifically including:

[0047] See also Figure 2 , when the voltage of the primary DC bus is in a first preset interval, starting the energy storage device to charge until it is fully charged;

[0048] When there is sufficient photovoltaic power and wind power, photovoltaic and wind power generation are given priority for use in the DC distribution system: first, the power supply of the DC load is guaranteed; secondly, when the load power supply is met, the excess power is used to charge energy storage equipment and electric vehicles; finally, the excess power is fed back to the AC power grid through the charging device.

[0049] When photovoltaic power is insufficient but wind power is sufficient, such as in rainy and windy weather, wind power generation is used first for the DC distribution system: first, the power supply of the DC load is guaranteed; second, when the load power supply is met, the excess power is used to charge energy storage equipment and electric vehicles; finally, the excess power is fed back to the AC grid through the charging device.

[0050] When the voltage of the primary DC bus is in the second preset interval, the charging pile and the low-voltage DC load are powered, and the charging state of the energy storage device is turned off;

[0051] When photovoltaic and wind power only meet the electricity demand of DC load, first ensure the power supply of DC load and shut down the charging state of energy storage equipment.

[0052] When the voltage of the primary DC bus is within a third preset interval, it is determined that photovoltaic and wind power generation is insufficient, the discharge state of the energy storage device is turned on, and the energy storage device supplies power to the DC distribution network;

[0053] See also Figure 3 When photovoltaic and wind power are insufficient and the energy storage device has power, the energy storage device generates electricity for use in the DC distribution network, and can be used in conjunction with electric vehicles to feed power to the DC distribution network.

[0054] See also Figure 4 , when the voltage of the primary DC bus is in a fourth preset interval, it is determined that both photovoltaic and energy storage are insufficient, and the discharge state of the charging pile is turned on;

[0055] See also Figure 5 When photovoltaic, wind and energy storage are insufficient, the power grid is rectified and supplied to the DC distribution network to supply power to DC loads and charging piles.

[0056] When the voltage of the primary DC bus is lower than the preset threshold, the rectification function of the charging device is turned on, and the AC power grid supplies power to the DC distribution network. When photovoltaic, wind power and energy storage are insufficient and the electric vehicle needs to be charged, the AC power grid is rectified and supplied to the DC nanogrid.

[0057] The operating method of the zero-carbon power distribution system of the source-grid-load-storage charging of the present invention effectively improves the zero-carbon power distribution system's ability to accept new energy. By configuring energy storage of reasonable capacity and adopting a hierarchical control strategy, it coordinates the cross-station consumption of distributed photovoltaic power, promotes the optimal configuration of energy in a larger range, and improves the efficiency of clean energy consumption. It can use the AC power grid to supply power when the distributed new energy generation is insufficient or unstable to ensure the stable operation of the DC load. It can also transmit excess electric energy to the AC power grid when the distributed new energy generation is excessive, ensuring the stability or flexibility of the DC load power supply, making energy management more efficient. At the same time, the power management system monitoring system performs carbon flow analysis and monitoring on each link, and at the same time receives the electric energy data of each branch of the system measured by the electric energy meter, and calculates and monitors the carbon emissions of each link in real time. Provide support for efficient emission reduction strategies.

[0058] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0059] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0060] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0061] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A zero-carbon power distribution system with source, grid, load, storage and charging, characterized in that: It includes an AC power grid, a charging device, a DC distribution network and a power management system; the two AC power grids are connected to the DC distribution network through the charging device; the power management system is connected to the AC power grid and the DC distribution network respectively; the DC distribution network is provided with DC buses of different voltage levels, and supplies power to different DC loads through the DC buses of different voltage levels; The power management system is used to monitor the electrical parameters of the DC distribution network and the AC power grid. When it is monitored that the DC distribution network is under-generated, the AC power grid supplies power to the DC distribution network through the charging device. When it is monitored that the DC distribution network is over-generated, the DC distribution network supplies power to the AC power grid through the charging device.

2. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 1, characterized in that: The power management system is also used to monitor the carbon emissions of each link in the AC power grid and the DC power distribution network in real time.

3. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 2, characterized in that: It also includes an electric energy meter; the electric energy meter is arranged in the branches of the AC power grid and the DC distribution network, and is used to measure the electric energy of each branch of the system and transmit the measured data to the power management system.

4. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 3, characterized in that: The DC distribution network includes a photovoltaic generator set, a wind generator set, a transformer, a primary DC bus, a secondary DC bus, a charging pile and a secondary DC load; the photovoltaic generator set and the wind generator set are both connected to the primary DC bus; the primary DC bus is directly connected to the charging pile; the primary DC bus is also directly connected to the secondary DC bus through the transformer; the secondary DC bus is connected to the secondary DC load.

5. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 4, characterized in that: The charging pile is a bidirectional DC charging pile.

6. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 4, characterized in that: The DC distribution network further includes an energy storage device and an energy storage converter, and the energy storage device is connected to the primary DC bus through the energy storage converter.

7. A zero-carbon power distribution system for source-grid-load-storage charging according to claim 6, characterized in that: When it is monitored that the DC distribution network generates insufficient power, the AC network supplies power to the DC distribution network through the charging device; when it is monitored that the DC distribution network generates excess power, the DC distribution network supplies power to the AC network through the charging device, specifically including: When the voltage of the primary DC bus is in the first preset interval, it is determined that the photovoltaic and wind power generation is sufficient, and the energy storage device is started to charge until it is fully charged; When the voltage of the primary DC bus is in the second preset interval, the charging pile and the low-voltage DC load are powered, and the charging state of the energy storage device is turned off; When the voltage of the primary DC bus is within a third preset interval, it is determined that photovoltaic and wind power generation is insufficient, the discharge state of the energy storage device is turned on, and the energy storage device supplies power to the DC distribution network; When the voltage of the primary DC bus is within a fourth preset interval, it is determined that photovoltaic power generation, wind power generation and energy storage are insufficient, and the discharge state of the charging pile is turned on; When the voltage of the primary DC bus is lower than a preset threshold, the rectification function of the charging device is turned on, and the AC power grid supplies power to the DC distribution network.

8. The zero-carbon power distribution system of source-grid-load-storage charging according to claim 4 is characterized in that: The AC power grid includes an AC load and an AC bus; the AC load is connected to the AC bus; and the AC bus is connected to the primary DC bus through the charging device.

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