A solar photovoltaic and solar thermal complementary power generation system for isolated power grid

Abstract

The present application discloses a solar photovoltaic and photothermal complementary power generation system for an isolated power grid, comprising a photothermal power station, a photovoltaic power station, a photothermal and photovoltaic complementary power generation control system, and a transformer and boost device, wherein the photothermal power station comprises a heat storage system, and the installed capacity of the photothermal and photovoltaic station is: the maximum power load of the isolated power grid / (1-photothermal plant power consumption rate); the installed capacity of the photovoltaic power station is: (isolated grid power load at noon-photothermal minimum operating load online power) / system efficiency of the photovoltaic power station; the photothermal and photovoltaic complementary power generation control system comprises a meteorological forecast system, a photovoltaic power generation forecast system and a photothermal power generation control system; the transformer and boost device is shared by the photothermal and photovoltaic power stations.

Description

Technical Field

[0001] The present invention relates to the technical field of solar power generation, and more specifically, to a solar photovoltaic and photothermal complementary power generation system for an isolated power grid. Background Art

[0002] With the rapid development of social economy, energy demand is increasing day by day. Traditional energy produces a lot of pollution during use, and solar power generation technology has developed rapidly as a clean and efficient energy supply method.

[0003] In remote areas, the cost of setting up power grid lines is very high. Therefore, solar thermal power generation and photovoltaic power generation can be used to build an isolated power grid to provide power supply for surrounding residents and industrial sectors.

[0004] Photovoltaic power generation has the advantages of high photoelectric conversion efficiency and low cost. However, due to the change in the intensity of sunlight, the power of the photovoltaic power generation system fluctuates greatly, and there is a phenomenon of daytime power generation and nighttime stoppage, which makes it difficult for photovoltaic power stations to provide continuous and stable power supply. CSP power stations with heat storage can overcome the changes in sunlight and weather, provide stable power supply, and have good rapid load adjustment capabilities. However, when operating in an isolated grid, the CSP power station cannot obtain electricity from the external grid when it starts, and the cost is high. The photovoltaic power station in the isolated grid can provide electricity for the start-up of the CSP power station, which is also conducive to reducing the overall cost of complementary power generation.

[0005] Increasing the proportion of photovoltaic installed capacity is conducive to reducing costs, but it cannot provide stable power delivery and cannot generate electricity in rainy days and at night; increasing the proportion of solar thermal installed capacity is conducive to continuous and stable power delivery but the cost is higher than photovoltaics.

[0006] Therefore, how to configure the installed capacity ratio of photovoltaic and solar thermal complementary power generation, and how to achieve complementary power generation between the two have become issues that need to be urgently resolved. Summary of the invention

[0007] Aiming at the isolated power grid formed by solar thermal power station and photovoltaic power station, a solar photovoltaic and solar thermal complementary power generation system for the isolated power grid is proposed, which combines solar thermal power generation and photovoltaic power generation, complements each other's advantages, improves the load change absorption capacity of the isolated power grid, and improves the stability of the isolated power grid.

[0008] In a first aspect, a solar photovoltaic and photothermal complementary power generation system for an isolated power grid is provided, comprising: a photothermal power station, a photovoltaic power station, a photothermal and photovoltaic complementary power generation control system, and a transformer and boost device, wherein the photothermal power station comprises a heat storage system, and the installed capacity of the photothermal power station is: the maximum power load of the isolated power grid / (1-photothermal plant power consumption rate); the installed capacity of the photovoltaic power station is: (isolated grid power load at noon - photothermal minimum operating load online power) / system efficiency of the photovoltaic power station; the photothermal and photovoltaic complementary power generation control system comprises a meteorological forecast system, a photovoltaic power generation forecast system and a photothermal power generation control system; the transformer and boost device are shared by the photothermal power station and the photothermal power station.

[0009] In combination with the first aspect, in a first possible implementation of the first aspect, the meteorological forecasting system is used to collect and predict meteorological parameters, and transmit the meteorological parameters to the photovoltaic power generation forecasting system, wherein the meteorological parameters include at least one of the following: light resources, temperature, and wind speed; the photovoltaic power generation forecasting system is used to predict the photovoltaic power generation output parameters of the photovoltaic power station within a short period according to the current operating parameters of the photovoltaic power station and the meteorological parameters, wherein the short period is between 1 minute and 30 minutes; the photovoltaic power generation forecasting system is also used to send the photovoltaic power generation forecasting system to the solar thermal power generation control system; the solar thermal power generation control system is used to determine the output demand of the solar thermal unit of the solar thermal power station according to the current grid load demand and the photovoltaic power generation output parameters; the solar thermal power generation control system is also used to control the power generation output of the solar thermal unit; the solar thermal power generation control system is also used to monitor the output of the photovoltaic power station, and correct the photovoltaic power generation forecasting system according to the monitoring results; the solar thermal power generation control system is also used to monitor the output of the solar thermal power station, and correct the control of the power generation output of the solar thermal unit according to the monitoring results.

[0010] In combination with the first aspect and the above-mentioned implementation manner, in a second possible implementation manner of the first aspect, the solar thermal power station includes a solar mirror field or a collector field, a heat absorption or collection component, a heat storage component, a heat exchange flow regulating valve, a steam generating or heat exchange component, a steam turbine, a generator, and a condenser.

[0011] In combination with the first aspect and the above-mentioned implementation manner, in a third possible implementation manner of the first aspect, the heat storage capacity of the heat storage component is calculated according to the following calculation formula: the heat storage capacity is greater than the average load of the isolated grid at nighttime power demand*16 hours / the average thermal-to-electric conversion efficiency of the turbine at nighttime.

[0012] In combination with the first aspect and the above-mentioned implementation manners, in a fourth possible implementation manner of the first aspect, the heat storage medium of the solar thermal power station is one or more of nitrate, concrete and thermochemical medium.

[0013] In combination with the first aspect and the above-mentioned implementation manners, in a fifth possible implementation manner of the first aspect, the solar thermal power generation control system is used to adjust at least one of the following parameters: the flow rate of the heat storage medium and the water working fluid at the inlet of the steam generating or heat exchanging component, and the temperature of the water working fluid by adjusting the heat exchange flow regulating valve of the steam generating or heat exchanging component of the solar thermal power station.

[0014] In combination with the first aspect and the above-mentioned implementation manner, in a sixth possible implementation manner of the first aspect, the photovoltaic power station includes a photovoltaic cell assembly, a combiner box, and an inverter.

[0015] In combination with the first aspect and the above-mentioned implementation manners, in a seventh possible implementation manner of the first aspect, the source of the isolated power grid power includes at least the solar thermal power station and the photovoltaic power station.

[0016] In combination with the first aspect and the above-mentioned implementation manners, in an eighth possible implementation manner of the first aspect, the photovoltaic power station is configured with a battery, the capacity of the battery meets the power requirement of the black start of the solar thermal power station, and meets the power capacity requirement of adjusting the mirror field of the solar thermal power station to a safe position, and the battery is also used as a protective safety power supply for the solar thermal power station.

[0017] To sum up, the advantages of the present invention are: for the isolated power grid formed by solar thermal and photovoltaic power generation, the solar thermal and photovoltaic power generation complementary control system is adopted, which can not only overcome the changes in sunlight and weather, but also quickly respond to changes in grid load demand, provide continuous and stable power supply, and help reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a solar photovoltaic and solar thermal complementary power generation system for an isolated power grid.

[0019] Figure 2 This is a schematic diagram of the structure of a solar photovoltaic and solar thermal complementary power generation system for an isolated power grid. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of the present invention.

[0021] The present invention has developed a solar photovoltaic and photothermal complementary power generation system for an isolated power grid. The principle diagram of the system is as follows: Figure 1As shown, the structural diagram is as follows Figure 2 As shown, it includes a solar thermal power station 1 equipped with a heat storage system, a photovoltaic power station 2, and a solar thermal and photovoltaic power generation complementary control system 3.

[0022] The solar thermal power station equipped with a heat storage system focuses sunlight onto a heat absorbing or collecting component 12 through a solar mirror field or a heat collecting field 11. The heat storage medium absorbs heat in the heat absorbing or collecting component 12 and enters a hot salt tank 131 in the heat storage component 13. The heat storage medium flows out of the hot salt tank 131, and the heat exchange flow regulating valve 14 adjusts the flow of the heat storage medium entering the steam generating or heat exchanging component 15. The heat storage medium and the water working medium exchange heat in the steam generating or heat exchanging component 15. The heat storage medium after releasing heat returns to the cold salt tank 132 in the heat storage component 13. The heat storage medium enters the heat absorbing or collecting component 12 from the cold salt tank 132 to absorb heat, thereby completing the heat storage medium endothermic and heat release cycle. After the steam generating or heat exchanging component 15 absorbs heat, the water medium becomes high-temperature and high-pressure water vapor, which enters the steam turbine 16 to perform work. The steam turbine 16 drives the generator 17 to rotate. The generator 17 outputs AC power and is connected to the transformer and booster device 4. The high-temperature and high-pressure water vapor enters the condenser 18 after performing work in the steam turbine 16. After condensing in the condenser 18, it enters the steam generating or heat exchanging component 15 to continue absorbing heat, thereby completing the entire cycle.

[0023] The photovoltaic power station 2 converts solar energy into electrical energy through a number of photovoltaic cell modules 21. The current enters the combiner box 22 and passes through the inverter 23 to be connected to the transformer and booster device 4 shared with the solar thermal power station after reactive power compensation.

[0024] The solar-thermal-photovoltaic power generation complementary control system 3 includes a meteorological forecasting system 31, a photovoltaic power generation forecasting system 32 and a solar-thermal power generation control system 33. The light resources, temperature, wind speed and other parameters in the meteorological forecasting system 31 are input into the photovoltaic power generation forecasting system 32. According to the current operating status parameters of the photovoltaic power station, the photovoltaic power generation change from 1 minute to 30 minutes is predicted, and the previous prediction results are corrected. The photovoltaic power generation prediction results are input into the solar-thermal power generation control system 33. According to the load demand of the electric power isolated grid, the power generation of the solar-thermal unit is adjusted to achieve the matching of photovoltaic and solar-thermal power generation with the load demand.

[0025] When the sunlight is strong and the grid load is low, part of the output of the photovoltaic power station 2 and the solar thermal power station 2 can be used to provide electricity to the grid, and the heat storage component 13 of the solar thermal power station 1 can be used to store energy.

[0026] When meteorological conditions or grid load demand fluctuates, the meteorological forecasting system 31 predicts the light resources, temperature, and wind speed in 1 to 30 minutes, and then the photovoltaic power generation prediction system 32 predicts the changes in photovoltaic power generation in 1 to 30 minutes. According to the grid load demand, the solar thermal power generation control system 33 quickly adjusts the flow of heat storage medium and water working fluid at the inlet of the steam generating or heat exchange component 15 of the solar thermal power station, and then adjusts the work of the steam turbine 16 and the power generation of the generator 17, so as to quickly absorb the changes in meteorological conditions and fluctuations in grid load demand, and ensure that the power generation of the photovoltaic power station 2 and the solar thermal power station 1 meets the current isolated grid load demand.

[0027] When there is no sunlight at night, the photovoltaic power station 2 cannot provide electricity, and the solar thermal power station 1 can use the heat storage component 13 to continuously generate electricity and provide a stable power supply for the isolated grid.

[0028] When the solar thermal power station 1 in the isolated power grid is started, the photovoltaic power station 2 can be used to provide power for the startup of the solar thermal power station.

[0029] The solar photovoltaic and photothermal complementary power generation system for the power isolated grid in this example can quickly adjust the photothermal power generation according to the meteorological forecast results and the photovoltaic power generation forecast results, thereby ensuring that the power output by the photovoltaic and photothermal power stations can meet the fluctuation of the power load of the isolated grid, absorb the changes in meteorological conditions, and provide a stable and continuous power supply. A person of ordinary skill in the art can appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. 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.

[0030] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0031] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0032] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0033] 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.

[0034] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including 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 methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0035] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A solar photovoltaic and solar thermal complementary power generation system for isolated power grids. It is characterized in that include: Solar thermal power station, photovoltaic power station, solar thermal photovoltaic power generation complementary control system, voltage conversion and boosting device, among which, The CSP power station includes a heat storage system, and the installed capacity of the CSP power station is: the maximum power load of the isolated power grid / (1-power consumption rate of the CSP plant); The installed capacity of the photovoltaic power station is: (isolated grid power load at noon - solar thermal minimum operating load online power) / system efficiency of the photovoltaic power station; The solar-thermal-photovoltaic power generation complementary control system includes a meteorological forecasting system, a photovoltaic power generation forecasting system and a solar-thermal power generation control system; the meteorological forecasting system is used to collect and forecast meteorological parameters, and transmit the meteorological parameters to the photovoltaic power generation forecasting system; the photovoltaic power generation forecasting system is used to forecast the photovoltaic power generation output parameters of the photovoltaic power station in a short period of time according to the current operating parameters of the photovoltaic power station and the meteorological parameters; the photovoltaic power generation forecasting system is also used to send the photovoltaic power generation forecasting system to the solar-thermal power generation control system; the solar-thermal power generation control system is used to forecast the photovoltaic power generation output parameters of the photovoltaic power station in a short period of time according to the current operating parameters of the photovoltaic power station and the meteorological parameters; The photovoltaic power generation output parameter is used to determine the output demand of the photovoltaic unit of the photovoltaic power station; the photovoltaic power generation control system is also used to control the power generation output of the photovoltaic unit; the photovoltaic power generation control system is also used to monitor the photovoltaic power generation output, and to correct the photovoltaic power generation prediction system according to the monitoring results; the photovoltaic power generation control system is also used to monitor the power generation output of the photovoltaic unit, and to correct the control of the power generation output of the photovoltaic unit according to the monitoring results; the meteorological parameters include at least one of the following: light resources, temperature, wind speed; the short-term cycle duration is between 1 minute and 30 minutes; The voltage transformation and boosting device is shared by the solar thermal power station and the solar thermal power station; The photovoltaic power station comprises a photovoltaic cell assembly, a junction box and an inverter.

2. A solar photovoltaic and solar thermal complementary power generation system for an isolated power grid according to claim 1, It is characterized in that The solar thermal power station includes a solar mirror field or a heat collection field, a heat absorption or heat collection component, a heat storage component, a heat exchange flow regulating valve, a steam generation or heat exchange component, a steam turbine, a generator, and a condenser.

3. A solar photovoltaic and solar thermal complementary power generation system for an isolated power grid according to claim 2, It is characterized in that The heat storage capacity of the heat storage component is calculated according to the following calculation formula: the heat storage capacity is greater than the average load of the isolated grid at night power demand*16 hours / the average thermal-electric conversion efficiency of the steam turbine at night.

4. A solar photovoltaic and solar thermal complementary power generation system for an isolated power grid according to claim 2, It is characterized in that The heat storage medium of the solar thermal power station is one or more of nitrate, concrete and thermochemical medium.

5. A solar photovoltaic and photothermal complementary power generation system for an isolated power grid according to any one of claims 1 to 2, It is characterized in that The solar thermal power generation control system is used to adjust at least one of the following parameters: the flow rate of the heat storage medium and the water working medium at the inlet of the steam generation or heat exchange component, and the temperature of the water working medium by adjusting the heat exchange flow control valve of the steam generation or heat exchange component of the solar thermal power station.

6. A solar photovoltaic and solar thermal complementary power generation system for an isolated power grid according to claim 1, It is characterized in that The sources of the isolated power grid electricity include at least the solar thermal power station and the photovoltaic power station.

7. A solar photovoltaic and solar thermal complementary power generation system for an isolated power grid according to claim 1, It is characterized in that The photovoltaic power station is equipped with a battery, the capacity of which meets the power requirement of the dark start of the solar thermal power station and the power capacity requirement of adjusting the mirror field of the solar thermal power station to a safe position. The battery is also used as a protective safety power supply for the solar thermal power station.

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