Group string type optical storage all-in-one machine system

Abstract

The invention discloses a string type optical storage all-in-one machine system which comprises a boosting transformer, a string type optical storage all-in-one machine, a switch and an optical storage controller. The plurality of string type optical storage all-in-one machines are arranged in parallel; the plurality of string type optical storage all-in-one machines are respectively connected with the boosting transformer and the optical storage controller; and the optical storage controller is connected with the switch. According to the string type light storage all-in-one machine system, abandoned light and limited power on the inverter side can be absorbed, the utilization hours of the whole photovoltaic station are increased, the power generation amount is increased, and the utilization rate of stored energy is increased; the equipment is high in integration level and convenient to transport, install and debug.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation, and in particular relates to a string-type integrated photovoltaic and storage system. Background Art

[0002] With the continuous advancement of technology, new energy has gradually become the main force in energy development. However, in the large-scale development of new energy, its output volatility, randomness, and the lack of inertia and damping characteristics of power electronic equipment have made it lack of active support capabilities, posing severe challenges to the stability and security of the power system and the balance of power and electricity, and becoming an important issue that needs to be addressed in the process of low-carbon transformation of the energy system. To this end, a series of measures need to be taken to strengthen the management and regulation of new energy grid connection to ensure the stability and reliability of the power system.

[0003] The topological structure of traditional photovoltaic power stations with energy storage can be roughly divided into two types. The first is a distributed energy storage arrangement. The photovoltaic strings are converted from direct current to alternating current through the inverter and connected to the low-voltage side of the sub-array step-up transformer. The energy storage is distributed near the transformer and connected to the low-voltage side of the step-up transformer to achieve low-voltage photovoltaic-storage AC coupling, and the electric energy is uniformly sent out by the step-up transformer. The second is centralized shared energy storage, that is, tens of megawatts or hundreds of megawatts of energy storage are concentrated in one place. After the electric energy is stepped up and collected, it is connected to the 35kV power grid to achieve medium-voltage photovoltaic-storage AC coupling.

[0004] The disadvantages of the above scheme are: for areas with good light resources, the inverter abandonment and power rationing rate remains high, and can even account for more than 30% of the annual power generation. The traditional low / medium voltage photovoltaic storage AC coupling cannot limit the power on the energy storage inverter side, causing a certain degree of power generation loss, weakening the purpose of configuring energy storage; and the traditional energy storage configuration can only achieve the effect of peak shaving and valley filling and smoothing the output curve, and cannot solve the current problem of photovoltaic lack of active support capacity, which has a greater impact on the grid side. Summary of the invention

[0005] In view of the above problems, the present invention discloses a string-type integrated photovoltaic storage system, comprising: a step-up transformer, a string-type integrated photovoltaic storage machine, a switch and a photovoltaic storage controller;

[0006] A plurality of the string-type integrated photovoltaic and storage devices are arranged in parallel;

[0007] A plurality of the string-type photovoltaic storage integrated devices are respectively connected to a step-up transformer and a photovoltaic storage controller;

[0008] The optical storage controller is connected to the switch.

[0009] Furthermore, the photovoltaic string-type integrated energy storage device comprises a photovoltaic energy storage converter, a photovoltaic string and an energy storage battery;

[0010] The photovoltaic storage converter is connected to a step-up transformer;

[0011] A plurality of groups of photovoltaic strings are respectively connected to the photovoltaic storage inverter;

[0012] A plurality of groups of energy storage batteries are respectively connected to the photovoltaic storage inverter.

[0013] Furthermore, the photovoltaic storage converter includes multiple groups of maximum power trackers and DC converters;

[0014] The maximum power tracker is connected to the photovoltaic string;

[0015] The DC converter is connected to the energy storage battery.

[0016] Furthermore, busbars are also included;

[0017] A plurality of the photovoltaic storage converters are respectively connected to the busbar;

[0018] The busbar is connected to the step-up transformer.

[0019] Furthermore, the photovoltaic storage inverter supports a voltage level of 1000-1500 Vdc.

[0020] Furthermore, the switch is a GOOSE network switch.

[0021] Furthermore, the output voltage of the photovoltaic storage inverter is 800V.

[0022] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0023] 1. It can absorb the abandoned light and power restriction on the inverter side, increase the utilization hours of the entire photovoltaic station, increase the power generation, and improve the utilization rate of energy storage;

[0024] 2. The equipment has high integration, which is convenient for transportation, installation and commissioning;

[0025] 3. Relying on photovoltaic storage inverters and energy storage batteries to build "virtual inertia" to provide active support for frequency and voltage, while realizing optimal power and voltage distribution within the station, so that the photovoltaic station as a whole presents synchronized and grid-friendly characteristics.

[0026] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of a string-type integrated photovoltaic and storage system according to an embodiment of the present invention is shown.

[0029] Figure numerals: 1. Step-up transformer; 2. String-type photovoltaic storage integrated machine; 3. Switch; 4. Photovoltaic storage controller; 5. Photovoltaic storage inverter; 6. Maximum power tracker; 7. Photovoltaic string; 8. Energy storage battery; 9. DC converter; 10. Bus. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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.

[0031] Figure 1 FIG. 1 is a schematic diagram of a string-type integrated photovoltaic storage system according to an embodiment of the present invention. Figure 1 As shown, a string-type photovoltaic storage integrated machine system proposed by the present invention comprises: a step-up transformer 1, a string-type photovoltaic storage integrated machine 2, a switch 3 and a photovoltaic storage controller 4;

[0032] A plurality of the string-type integrated optical storage devices 2 are arranged in parallel;

[0033] The plurality of said string-type photovoltaic storage integrated devices 2 are electrically connected to the step-up transformer 1 and the photovoltaic storage controller 4 respectively;

[0034] The optical storage controller 4 is electrically connected to the switch 3 .

[0035] A step-up transformer 1 is used to step up the low-voltage AC power to a high voltage so that the power can be integrated into the power grid;

[0036] The photovoltaic string storage integrated machine 2 is used to invert the direct current generated by the photovoltaic string 7 and the energy storage battery 8 into alternating current, and transmit the electric energy to the low-voltage side of the step-up transformer 1;

[0037] Switch 3, used for uploading and interacting information between the optical storage controller 4 and the cluster cooperative control device of the station control layer; illustratively, switch 3 adopts a dedicated GOOSE network switch;

[0038] The optical storage controller 4 is used to receive the upper end scheduling instruction and realize the control of the optical storage system in the subarray.

[0039] In some embodiments, the photovoltaic string storage integrated machine 2 includes a photovoltaic storage converter 5, a photovoltaic string 7 and an energy storage battery 8;

[0040] The photovoltaic storage converter 5 is electrically connected to the step-up transformer 1;

[0041] The plurality of photovoltaic strings 7 are electrically connected to the photovoltaic storage inverter 5 respectively;

[0042] The plurality of energy storage batteries 8 are electrically connected to the photovoltaic storage inverter 5 respectively.

[0043] The photovoltaic storage inverter 5 is used to connect to the photovoltaic string 7 and the energy storage system to achieve DC side coupling connection of the photovoltaic and energy storage systems, and at the same time invert the DC power connected to the photovoltaic string 7 and the energy storage system into AC power; illustratively, the photovoltaic storage inverter 5 is a bidirectional photovoltaic storage inverter with an output voltage of 800V.

[0044] Photovoltaic string 7, used to connect 18 to 24 photovoltaic modules in series according to different power levels of the modules to form a photovoltaic string 7, and connect to the photovoltaic storage inverter 5 under the premise of meeting the access voltage level;

[0045] The energy storage battery 8 is used for storing and releasing electric energy, and can be an electrochemical energy storage such as lithium iron phosphate.

[0046] Among them, the energy storage battery 8 can use different types of energy storage according to actual working conditions, such as: power type / energy type, electrochemical / electromagnetic / mechanical type, etc.

[0047] In some embodiments, the photovoltaic storage converter 5 includes multiple groups of maximum power trackers 6 and direct current converters 9 (DC / DC);

[0048] The maximum power tracker 6 is electrically connected to the photovoltaic string 7;

[0049] The DC converter 9 is electrically connected to the energy storage battery 8 .

[0050] Maximum power tracker 6, used to detect the power generation voltage of the solar panel in real time and track the maximum voltage and current value to maximize the power generation of the component;

[0051] The DC converter 9 is used to stabilize the voltage and control the voltage level.

[0052] In some embodiments, the string-type integrated photovoltaic and storage system further includes a bus bar 10;

[0053] The plurality of photovoltaic storage converters 5 are electrically connected to the busbar 10 respectively;

[0054] The busbar 10 is electrically connected to the step-up transformer 1 .

[0055] For a certain collection area of ​​a single photovoltaic sub-array, a bidirectional photovoltaic storage inverter 5 is configured. The photovoltaic storage inverter 5 has multiple maximum power trackers 6 (MPPT) for photovoltaic strings 7 or energy storage batteries 8 to access. It needs to support 1000-1500Vdc voltage levels and can support the access of various types of components such as 182 components and 210 components. At the same time, a high-safety and high-reliability energy storage system suitable for photovoltaic storage integration is selected to meet various weather conditions and different temperature conditions. It can be directly connected to the multi-function and performance requirements of DC, and the safety meets the latest safety regulations. The service life is adapted to the photovoltaic life of the battery system. The photovoltaic storage inverter 5 is adaptable to various voltage levels and various component types. It is highly versatile and can be applied to various working conditions of photovoltaic power stations. After the photovoltaic strings 7 and energy storage batteries 8 are connected to the photovoltaic storage inverter 5 for inversion, several photovoltaic storage inverters 5 are connected to the step-up transformer 1 with 800V AC power to realize the transmission of electric energy.

[0056] Communication control architecture:

[0057] On the photovoltaic sub-array side, a photovoltaic storage controller 4 is set up, and the photovoltaic storage converter 5 communicates with the photovoltaic storage controller 4 through the power carrier. The photovoltaic storage controller 4 can receive dispatching instructions to realize the control of the photovoltaic storage system in the photovoltaic sub-array, and realize the peak regulation, frequency regulation, and voltage regulation control of the photovoltaic storage converter level. At the same time, a GOOSE network switch 3 is set up, and the photovoltaic storage controller 4 sends information to the cluster cooperative control device set up at the station control layer through the GOOSE network switch 3. The transmission medium can be the spare core of the optical cable laid in the sub-array or the newly added optical cable transmission. The cluster cooperative control device communicates with the dispatching data network access equipment, AGC system, and AVC system, comprehensively judges, issues dispatching instructions, and performs lean control to the photovoltaic storage converter side, realizing the smooth output and active support functions of the photovoltaic storage power station.

[0058] The present invention proposes a string-type photovoltaic storage integrated system, which configures energy storage on the DC side, constructs a string-level photovoltaic storage DC coupled topology, and sets a photovoltaic storage converter 5 with high conversion efficiency and low response time to replace the traditional string inverter. The present invention can achieve smooth photovoltaic output on the DC side, realize lean control of scheduling, avoid the inverter side power curtailment and power restriction that often occurs in traditional photovoltaic power stations, and increase the utilization hours of the entire photovoltaic station. At the same time, relying on the photovoltaic storage converter 5 and the energy storage battery 8 to build a "virtual inertia" to provide active support for frequency and voltage, and at the same time realize the optimization of power and voltage distribution inside the station, so that the photovoltaic station as a whole presents a synchronized and friendly grid-connected characteristic.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0063] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 invention. In the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine different embodiments or examples described in the present invention and features of different embodiments or examples without contradiction.

[0064] 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 make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A string-type integrated photovoltaic storage system, It is characterized in that include: A step-up transformer (1), a string-type photovoltaic storage integrated machine (2), a switch (3) and a photovoltaic storage controller (4); A plurality of the string-type integrated photovoltaic and storage devices (2) are arranged in parallel; A plurality of the string-type photovoltaic storage integrated devices (2) are respectively connected to a step-up transformer (1) and a photovoltaic storage controller (4); The optical storage controller (4) is connected to the switch (3).

2. The string-type integrated photovoltaic storage system according to claim 1, It is characterized in that The photovoltaic string-type integrated energy storage device (2) comprises a photovoltaic energy storage converter (5), a photovoltaic string (7) and an energy storage battery (8); The photovoltaic storage converter (5) is connected to the step-up transformer (1); A plurality of groups of photovoltaic strings (7) are respectively connected to the photovoltaic storage inverter (5); A plurality of groups of energy storage batteries (8) are respectively connected to the photovoltaic storage inverter (5).

3. The string-type integrated photovoltaic storage system according to claim 2, It is characterized in that The photovoltaic storage converter (5) comprises a plurality of groups of maximum power trackers (6) and direct current converters (9); The maximum power tracker (6) is connected to the photovoltaic string (7); The DC converter (9) is connected to the energy storage battery (8).

4. The string-type integrated photovoltaic storage system according to claim 2, It is characterized in that Also includes a busbar (10); The plurality of photovoltaic storage converters (5) are respectively connected to a bus bar (10); The busbar (10) is connected to the step-up transformer (1).

5. The string-type integrated photovoltaic and storage system according to claim 2, It is characterized in that The photovoltaic storage converter (5) supports a voltage level of 1000 to 1500 Vdc.

6. The string-type integrated photovoltaic and storage system according to claim 1, It is characterized in that The switch (3) is a GOOSE network switch.

7. The string-type integrated photovoltaic and storage system according to claim 2, It is characterized in that The output voltage of the photovoltaic storage inverter (5) is 800V.

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