Power supply system

Abstract

The utility model relates to a power supply system, which is used for supplying power to multiple paths of loads, the multiple paths of loads comprise an A-phase load, a B-phase load and a C-phase load, and the power supply system comprises a power grid system for providing first alternating current; the energy storage system provides second alternating current; the power grid system and the energy storage system each comprise a common connection point A-phase common terminal, a B-phase common terminal and a C-phase common terminal which are connected with the multiple loads in a one-to-one mode. Wherein the first alternating current provided by the power grid system supplies power to the energy storage system and the multi-path load, the second alternating current provided by the energy storage system supplies power to the multi-path load, and at least two paths of loads in the multi-path load have different maximum electric power. According to the power supply system provided by the invention, the stability and reliability of the power supply system can be improved while the load requirement is met.

Description

Technical Field

[0001] The present application relates to the technical field of power supply systems, and in particular to a power supply system that is collaboratively powered by a power supply grid and an energy storage system. Background Art

[0002] The use of three-phase four-wire for 10kV high-voltage transmission combined with energy storage system grid-connected power supply is a widely used power supply form. On the user side, the transformer transforms the voltage into 400V three-phase power to supply multiple loads. However, when the mains system and the energy storage system are jointly powered, the energy storage system absorbs or releases different electric energy at different times, and the load power connected to the phase lines of different phases is different, which can easily cause the power of the load connected to a certain phase line to exceed the power supply power of the single-phase electricity, resulting in unbalanced power supply, which may cause a certain phase of equipment to overload and cause power supply safety hazards. It may also cause the electric energy of the energy storage system to be fed back to the mains power grid, resulting in a waste of electric energy. Utility Model Content

[0003] Based on this, it is necessary to provide a power supply system that can reduce the power supply imbalance phenomenon that occurs during the power supply process.

[0004] A power supply system is used to supply power to multiple loads, wherein the multiple loads include an A-phase load, a B-phase load, and a C-phase load. The power supply system includes:

[0005] A power grid system, providing a first alternating current;

[0006] An energy storage system provides a second alternating current;

[0007] The power grid system and the energy storage system both include a common connection point A-phase common terminal, a B-phase common terminal and a C-phase common terminal connected one by one to multiple loads;

[0008] The first alternating current provided by the power grid system supplies power to the energy storage system and multiple loads, and the second alternating current provided by the energy storage system supplies power to the multiple loads, at least two of the multiple loads have different maximum power consumptions.

[0009] In one embodiment, the power grid system includes a power supply grid and a three-phase transformer; the primary side of the three-phase transformer is connected to the power supply grid, and the secondary side is connected to the A-phase common terminal, the B-phase common terminal and the C-phase common terminal respectively through the transformer A-phase connection terminal, the transformer B-phase connection terminal and the transformer C-phase connection terminal.

[0010] In one embodiment, the energy storage system includes an energy storage unit and a converter; the first end of the converter is connected to the energy storage unit, and the second end is connected to the A-phase common terminal, the B-phase common terminal and the C-phase common terminal respectively through the converter A-phase connection terminal, the converter B-phase connection terminal and the converter C-phase connection terminal; wherein the power value of the load with the smallest power consumption among the multiple loads is greater than or equal to one third of the discharge power of the energy storage unit.

[0011] In one embodiment, protection units are respectively arranged between the transformer A phase connecting terminal, the transformer B phase connecting terminal, the transformer C phase connecting terminal and the A phase common terminal, the B phase common terminal and the C phase common terminal.

[0012] In one embodiment, the converter is a bidirectional converter, which is used to convert a first AC power portion provided by the power grid system into DC power to supply the energy storage unit or to convert the DC power stored in the energy storage unit into a second AC power to supply multiple loads.

[0013] In one of the embodiments, a charging relay is provided between the converter and the power grid system.

[0014] In one of the embodiments, a discharge relay is provided between the converter and the multi-channel loads.

[0015] In one embodiment, the power supply system further comprises:

[0016] The energy management unit is respectively connected to the power grid system and the energy storage system for controlling the power grid system to supply power to multiple loads and the energy storage system or for controlling the energy storage system to supply power to multiple loads.

[0017] In one embodiment, the power grid system and the energy storage system both include an electric energy meter, which is connected to an energy management unit and transmits electricity usage information to the energy management unit.

[0018] In one embodiment, the converter and the A-phase load, the B-phase load and the C-phase load are all connected to the neutral line of the secondary side of the three-phase transformer.

[0019] The above-mentioned power supply system is used to supply power to multiple loads, and the multiple loads include A-phase load, B-phase load and C-phase load. The power supply system includes a power grid system, which provides a first alternating current; an energy storage system, which provides a second alternating current; the power grid system and the energy storage system both include a common connection point A-phase common terminal, a B-phase common terminal and a C-phase common terminal connected one by one to the multiple loads; wherein the first alternating current provided by the power grid system supplies power to the energy storage system and the multiple loads, and the second alternating current provided by the energy storage system supplies power to the multiple loads, and at least two of the multiple loads have different maximum power consumption. The power supply system can ensure that at least the minimum load demand of the three-phase load is met, which helps to avoid the energy storage system from feeding back to the power grid system during the discharge process, resulting in a waste of energy, and can improve the long-term sustainability, stability and reliability of the power supply of the energy storage system while meeting the load demand. At the same time, it can avoid the power consumption pressure on the power grid system caused by the different power consumption of multiple loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] FIG1 is a schematic diagram of the structure of a power supply system according to an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the line connection relationship of a power supply system according to an embodiment of the present application.

[0023] 11. Power grid; 12. Three-phase transformer; 21. Energy storage unit; 22. Converter; 31. A-phase load; 32. B-phase load; 33. C-phase load; 41. A-phase common terminal; 42. B-phase common terminal; 43. C-phase common terminal; 5. Protection unit. DETAILED DESCRIPTION

[0024] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0026] It is understood that the terms "transformer", "converter", etc. used in this application may be used herein to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component of the transformer from another component. For example, without departing from the scope of this application, a transformer resistor may be referred to as a converter resistor, and similarly, a converter resistor may be referred to as a transformer resistor. Both a transformer resistor and a converter resistor are resistors, but they are not the same resistor.

[0027] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0028] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0029] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0030] FIG1 is a schematic diagram of the structure of a power supply system according to an embodiment of the present application. Figure 2 FIG. 1 is a schematic diagram of the line connection relationship of the power supply system of an embodiment of the present application. Figure 2 As shown, an embodiment of the present application provides a power supply system for supplying power to a plurality of loads, wherein the plurality of loads include an A-line load, a B-line load, and a C-line load, wherein at least two of the A-line load, the B-line load, and the C-line load have different maximum single powers, and the power supply system includes:

[0031] A power grid system, providing a first alternating current;

[0032] An energy storage system provides a second alternating current;

[0033] The power grid system and the energy storage system both include a common connection point A-phase common terminal, a B-phase common terminal and a C-phase common terminal connected one by one to multiple loads;

[0034] The first AC power provided by the power grid system supplies power to the energy storage system and the multiple loads, and the second AC power provided by the energy storage system supplies power to the multiple loads, and at least two of the multiple loads have different maximum power consumptions. It can be understood that the first AC power provided by the power grid system supplies the energy storage system while supplying the multiple loads, and the second AC power provided by the energy storage system only supplies the multiple loads.

[0035] The three-phase AC power supply system is the most widely used power system at present, providing industrial, commercial and residential electricity. This power supply system provides three phases (i.e., phase A, phase B, and phase C) of AC power, and the phase difference between the three phases is 120°. Load is the general term for electrical equipment in the power system. The three-phase AC power supply system can be connected to single-phase loads or three-phase loads according to actual needs. Single-phase loads refer to loads or equipment powered by single-phase power supply. Relatively speaking, three-phase loads refer to loads or electrical equipment powered by three-phase power supply. The maximum power of the load refers to the rated power of the load, which represents the maximum power level at which the equipment can maintain normal operation. It is a parameter determined during the design or manufacture of the equipment. The rated power of different loads can be the same or different. A three-phase transformer refers to a transformer used to transform the voltage of a three-phase power supply from one voltage level to another. It usually has three independent coils or windings, each of which is connected to one phase of the power supply. The primary side refers to the input side of the transformer, and the secondary side refers to the output side of the transformer. When the power supply system is a three-phase four-wire system, the transformer can lead out the three-phase terminal through a star connection, that is, one terminal of the three secondary windings is connected together to form a common connection point, and the other three terminals correspond to the three phases respectively; when the power supply system has no neutral line, the three-phase terminal can be led out through a triangle connection. The power supply network is used to provide 10kV high-voltage three-phase alternating current, and the power supply network can be a municipal power grid. The three-phase transformer converts the 10kV high-voltage three-phase alternating current provided by the power supply network into a first alternating voltage, which can be a 0.4kV three-phase alternating current to meet the power demand of the load. The energy storage unit can be an energy storage battery, such as a lithium-ion battery, a lead-acid battery, a sodium-sulfur battery, or a lithium-sulfur battery. Different types of energy storage units can determine when to start charging or discharging under the control of the energy management unit. The discharge power of the energy storage unit is determined by the rated power of the battery or other energy storage device used in the energy storage unit. When charging, the energy storage unit converts the electric energy received from the power grid into an energy storage form corresponding to the energy storage unit through different energy storage methods, such as electrochemical energy storage or mechanical energy storage. The converter is an electronic device used in the energy storage system. Its function is to convert electric energy into AC or DC in a controllable manner, and output it for power supply or interact with the power grid when needed. It can control the conversion and flow of electric energy. When the power grid fails, the energy storage unit can be quickly switched to the power supply mode to ensure the power supply of critical loads. Electric energy can be received from a power source (such as a power grid) for storage, or the stored electric energy can be converted into a second AC voltage and output to the load, which is conducive to balancing the peak-to-valley difference of the power grid. Corresponding to the form of the power supply system, when the power supply system is a three-phase four-wire power supply, the converter can have a converter A phase connection terminal, a converter B phase connection terminal, a converter C phase connection terminal, and a converter neutral line connection terminal.The power value of the load with the smallest power among the single-phase loads is greater than or equal to one third of the discharge power of the energy storage unit. The composition of the energy storage unit can be determined according to the power of different loads, or appropriate loads can be connected to each phase line according to the composition of the energy storage unit so that the power of the load and the energy storage unit can meet the above relationship. Take the total power P of the distribution transformer. 总 =480kW, the power of the load on the A phase side P A =80kW, the power of the load on the B phase side P B =100kW, power P of the load on phase C C =120kW, the discharge power of the energy storage system P 放 =240kW and charging power P 充 =120KW as an example, when the municipal power grid is powered off, the energy storage system enters the discharge mode. The energy storage system converts the power into three-phase power after the bidirectional converter PCS to supply power to the load. The power provided by A1, B1, and C1 of the bidirectional converter PCS to the load is P 放 / 3=80kW, at this time, A1 phase: 80kW=P A , that is, 80kW = 80kW, the discharge power of phase A1 of the energy storage system is equal to the power required by the load on the phase A side, and no power from phase A1 will be fed back to the municipal power grid; phase B1: 80kW <P B , that is, 80kW<100kW, and no electric energy will be fed back to the municipal power grid; C1 phase: 80kW <P C , that is, 80kW<120kW, and no electric energy will be fed back to the municipal power grid. The above power supply system can meet the certain power demand of each phase load while avoiding the situation that when the power supply grid is cut off and the energy storage unit is used for power supply, the electric energy of the energy storage unit will not flow back to the power supply grid, causing equipment failure in the power grid or affecting the voltage stability during its recovery process.

[0036] The above-mentioned power supply system is used to supply power to the load, the load includes a single-phase load, the single-phase load includes an A-phase load, a B-phase load and a C-phase load, the maximum power of the A-phase load, the B-phase load and the C-phase load is different, and the power supply system includes: a three-phase transformer, the primary side of the three-phase transformer is connected to the power supply network, and the secondary side is connected to the A-phase load, the B-phase load and the C-phase load through the transformer A-phase connection terminal, the transformer B-phase connection terminal and the transformer C-phase connection terminal respectively; used to provide a first AC voltage; an energy storage unit, used to store energy and provide a second AC voltage; the power supply network provides basic power support, and the energy storage unit can adjust the power balance of the entire power supply system; the first end of the converter is connected to the energy storage unit, and the second The ends are connected to the A-phase load, the B-phase load and the C-phase load respectively through the A-phase connection terminal of the converter, the B-phase connection terminal of the converter and the C-phase connection terminal of the converter; they are used to control the charging and discharging of the energy storage unit; the converter controls the charging and discharging process of the energy storage unit, which helps to balance the power difference between the power supply network and the load; wherein the power value of the load with the smallest power among each single-phase load is greater than or equal to one third of the discharge power of the energy storage unit, so that the power supply system can meet the certain power demand of each phase load while avoiding the situation that when the power supply network is cut off and the energy storage unit is used for power supply, the electric energy of the energy storage unit flows back to the power supply network, causing equipment failure in the power grid or affecting the voltage stability during its recovery process.

[0037] In one embodiment, the power grid system includes a power supply network and a three-phase transformer; the primary side of the three-phase transformer is connected to the power supply network, and the secondary side is connected to the A-phase common terminal, the B-phase common terminal, and the C-phase common terminal through the transformer A-phase connection terminal, the transformer B-phase connection terminal, and the transformer C-phase connection terminal. Connecting the common phase terminals can ensure that the phase terminals of the transformer and the converter are consistent in potential, thereby maintaining phase consistency and improving anti-interference capabilities. It can also simplify the wiring structure of the system, reduce the complexity of installation and maintenance, and enable the power supply system to more flexibly adapt to different load types and requirements.

[0038] In one embodiment, the energy storage system includes an energy storage unit and an inverter; the first end of the inverter is connected to the energy storage unit, and the second end is connected to the common terminal of phase A, the common terminal of phase B and the common terminal of phase C respectively through the inverter A phase connection terminal, the inverter B phase connection terminal and the inverter C phase connection terminal; wherein the power value of the load with the smallest power consumption among the multiple loads is greater than or equal to one third of the discharge power of the energy storage unit. In this way, when the energy storage unit supplies power to multiple loads, the loads of each phase can be evenly distributed, ensuring that the discharge power of the energy storage system is not too large, reducing the pressure of the power supply system, and improving the reliability and life of the energy storage system, so that the electric energy of the energy storage unit can be more effectively utilized.

[0039] In one embodiment, the converter is a bidirectional converter, which is used to convert the first AC power provided by the power grid system into DC power to supply the energy storage unit or convert the DC power stored in the energy storage unit into the second AC power to supply multiple loads. The bidirectional converter can be used as an inverter to convert the DC power provided by the energy storage unit into AC power, and can also be used as a frequency converter to convert AC power into DC power, so that the energy storage unit can be charged, the charging and discharging process of the energy storage system can be adjusted, and the flexible scheduling of electric energy can be achieved. It can smooth the power fluctuations in the power supply system, provide backup power when the power grid is out of power, and improve the overall reliability and stability of the power supply system.

[0040] In one embodiment, a charging relay is provided between the converter and the power grid system. The charging relay may include a charging relay which generally includes an electromagnetic relay, a current sensor, a voltage sensor, and a related control circuit. Among them, the current sensor and the voltage sensor are used to monitor the changes in the system current and voltage, and the electromagnetic relay is used to perform protection and control operations, which are used to prevent the energy storage unit from being damaged due to current shock during charging and to keep the charging current within a safe range. When an overcurrent occurs, the charging relay can trigger a protection operation to avoid damage to the energy storage unit.

[0041] In one embodiment, a discharge relay is provided between the converter and the multi-channel loads. The structure principle of the discharge relay is similar to that of the discharge relay, and its function is to control the current level during the discharge process of the energy storage unit to prevent over-discharge and other phenomena from damaging the energy storage unit.

[0042] In one of the embodiments, the power supply system further includes: an energy management unit, which is communicatively connected to the power grid system and the energy storage system, respectively, and is used to control the power grid system to supply power to multiple loads and the energy storage system, or to control the energy storage system to supply power to multiple loads. The energy management unit is a subsystem in the power supply system used to monitor, control and optimize energy usage. It adjusts the operating parameters of the energy system by real-time processing and analyzing information such as power load, energy flow, temperature, humidity, etc., and coordinates and schedules the work of various energy equipment. As shown in Figure 1, the energy management unit can be communicatively connected to the online / offline meter on the input side of the transformer, so that different data on the energy storage unit side, the user side and the power supply side can be obtained, so as to manage the power supply process more comprehensively.

[0043] In one embodiment, the power grid system and the energy storage system both include an energy meter, which is connected to the energy management unit, and the energy meter transmits the electricity usage information to the energy management unit. As shown in FIG1 , the first end of the meter can be connected to the charging relay and the discharging relay, and the other end is connected between the converter and the energy management unit. The same meter can be used to measure various electrical parameters of the charging and discharging process, or two or more meters can be used to measure different electrical parameters of the charging and discharging process respectively. In this way, the amount of electricity input to the converter and the amount of electricity output by the converter can be accurately measured, and the metering data obtained can be used to analyze the performance of the energy storage unit and the converter, which is beneficial to improving the utilization efficiency of electric energy.

[0044] In one embodiment, the converter and the A-phase load, the B-phase load and the C-phase load are all connected to the neutral line of the secondary side of the three-phase transformer. Figure 2 As shown, the neutral terminal of the converter can be connected to the neutral common connection terminal of the neutral terminal of the three-phase transformer to achieve connection with the neutral line. In this way, the converter and each phase load can share the neutral point, so that each phase line can independently supply power to the single-phase load, and by adjusting the current of each phase, it is beneficial to improve the three-phase imbalance phenomenon and enhance the stability of the power supply system.

[0045] It is understood that the specific connection mode of the above components can also adopt other forms, not limited to the forms mentioned in the above embodiments, as long as they can complete the corresponding functions. The voltages on the power supply side and the user side are also not limited to 10kV and 0.4kV, and can also be other values.

[0046] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0047] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A power supply system, characterized in that: Used to supply power to multiple loads, the multiple loads include A-phase load, B-phase load and C-phase load, the power supply system includes: A power grid system, providing a first alternating current; An energy storage system provides a second alternating current; The power grid system and the energy storage system both include a common connection point A-phase common terminal, a B-phase common terminal and a C-phase common terminal connected one by one to the multiple loads; The first alternating current provided by the power grid system supplies power to the energy storage system and the multiple loads, the second alternating current provided by the energy storage system supplies power to the multiple loads, and at least two of the multiple loads have different maximum power consumptions.

2. The power supply system according to claim 1, characterized in that: The power grid system includes a power supply network and a three-phase transformer; The primary side of the three-phase transformer is connected to the power supply network, and the secondary side is connected to the A-phase common terminal, the B-phase common terminal and the C-phase common terminal respectively through the transformer A-phase connection terminal, the transformer B-phase connection terminal and the transformer C-phase connection terminal.

3. The power supply system according to claim 2, characterized in that: The energy storage system comprises an energy storage unit and a converter; The first end of the converter is connected to the energy storage unit, and the second end is connected to the A-phase common terminal, the B-phase common terminal and the C-phase common terminal respectively through the converter A-phase connecting terminal, the converter B-phase connecting terminal and the converter C-phase connecting terminal; Among them, the power value of the load with the smallest power consumption among the multiple loads is greater than or equal to one third of the discharge power of the energy storage unit.

4. The power supply system according to claim 2, characterized in that: Protection units are respectively arranged between the transformer A phase connection terminal, the transformer B phase connection terminal, the transformer C phase connection terminal and the A phase common terminal, the B phase common terminal and the C phase common terminal.

5. The power supply system according to claim 3, characterized in that: The converter is a bidirectional converter; the bidirectional converter is used to convert the first AC power provided by the power grid system into DC power to supply the energy storage unit or convert the DC power stored in the energy storage unit into the second AC power to supply multiple loads.

6. The power supply system according to claim 5, characterized in that: A charging relay is provided between the converter and the power grid system.

7. The power supply system according to claim 5, characterized in that: A discharge relay is provided between the converter and the multiple loads.

8. The power supply system according to claim 1, characterized in that: The power supply system further comprises: An energy management unit is respectively connected to the power grid system and the energy storage system for controlling the power grid system to supply power to the multiple loads and the energy storage system or for controlling the energy storage system to supply power to the multiple loads.

9. The power supply system according to claim 8, characterized in that: The power grid system and the energy storage system both include an electric energy meter, which is connected to the energy management unit and transmits electricity usage information to the energy management unit.

10. The power supply system according to claim 3, characterized in that: The converter and the A-phase load, the B-phase load and the C-phase load are all connected to the neutral line of the secondary side of the three-phase transformer.

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