A solar thermal and photovoltaic complementary and collaborative power generation system and operation method

Abstract

The present invention discloses a photovoltaic-thermal complementary and collaborative power generation system and an operation method thereof, which includes a photovoltaic power station, a solar thermal power station, an electric heating system, a busbar system, a control system and a power grid. The photovoltaic power station includes a photovoltaic array and an inverter, and the solar thermal power station includes a solar thermal collector system, a heat storage system and a power generation system. The output end of the photovoltaic array is connected to the power supply interface of the electric heating system and the busbar system through the inverter. The solar thermal collector system is connected to the heat storage system, the heat storage system is connected to the power generation system, the output end of the power generation system is connected to the busbar system, the control system is connected to the control end of the busbar system, and the output end of the busbar system is connected to the power grid. This system and operation method can achieve complementary and collaborative power generation of photovoltaic and solar thermal, and have strong self-regulation ability.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar power generation, and relates to a solar thermal and photovoltaic complementary and collaborative power generation system and an operation method thereof. Background Art

[0002] Solar power generation mainly includes two technical forms: photovoltaic and solar thermal power generation. Because the self-regulation ability of photovoltaic power generation is weak, there is often a certain proportion of light abandonment rate during power consumption. At present, some regions have introduced relevant supporting documents for photovoltaic with energy storage. A pure photovoltaic power station can achieve parity or lower than parity grid connection. However, due to the high cost of the battery energy storage system, the current pure photovoltaic energy storage mode is hardly economical. Since the solar thermal power station is equipped with a heat storage system, it has a strong regulation ability, and its regulation range is approximately from 0% to 100%. If the photovoltaic and solar thermal systems are combined, the regulation ability of solar thermal can be used to suppress the power fluctuation of photovoltaic on the system, or achieve peak-shifting power generation. Economically, the electric energy of a low-cost photovoltaic power station can be used to reduce the power generation cost of the solar thermal power station, or (partially) replace the self-use power of the solar thermal power station. By complementing and collaborating the photovoltaic and solar thermal systems for power generation, the regulation capabilities of both can be maximized to achieve maximum profit.

[0003] At present, many scholars and enterprises have conducted research on photovoltaic-thermal complementary power generation. The main relevant research results are as follows:

[0004] Chinese Patent CN203984349U proposes a quickly transformable photovoltaic-thermal integrated distributed system. Chinese Patent CN107702194A proposes a photovoltaic-thermal power generation and heating system and a control method. Chinese Patent CN205754215U proposes a photovoltaic-thermal integrated system. The above three patents all realize photovoltaic-thermal co-generation through concentrating photovoltaic technology, which is the combination of component-level photovoltaic-thermal power generation technology. The main technical route is still photovoltaic power generation, which is completely different from the solar thermal steam power generation system described in this patent.

[0005] Chinese Patent CN209692366U proposes a solar photovoltaic and thermal complementary power generation system for an isolated power grid, which realizes complementary power generation of a photovoltaic-thermal power station through a complementary control system. In this system, except for the meteorological prediction system, photovoltaic and solar thermal operate independently, which is different from the complementary and collaborative power generation system described in this patent.

[0006] Chinese Patent CN110429667A proposes a method for configuring the capacity of a thermal photovoltaic bundled power generation system based on cuckoo search, which can minimize the standard deviation of the output of the photovoltaic-thermal bundled power generation system. In this system, photovoltaic and solar thermal operate independently. Based on the output prediction of the two, with the minimum standard deviation of the output as the goal, the output configuration of the two is optimized. The optimization process does not consider the electricity price factor and does not optimize the maximum benefit of the power station, which is different from the complementary and collaborative power generation system and operation method described in this patent.

[0007] Chinese patent CN202872690U proposes a device that uses translucent photovoltaic cells combined with solar thermal power generation. It uses high-transmittance photovoltaic cells and concentrating equipment to achieve comprehensive utilization of photovoltaic and solar thermal power generation. This system is also a component-level innovation and does not mention the photovoltaic and solar thermal system. It is different from the complementary and synergistic power generation system described in this patent.

[0008] Chinese patent CN105007038A proposes a photovoltaic-assisted power generation system for a solar thermal power station, which realizes photovoltaic-assisted solar thermal power generation by installing photovoltaic panels above the Fresnel secondary reflector. In this system, photovoltaic and solar thermal systems operate independently, and there is no complementary and synergistic function in the system structure.

[0009] Chinese patent CN106330093A proposes an integrated photovoltaic and solar thermal power generation system. This system heats water through photovoltaic power generation, which is then fed into a solar thermal collector system to achieve hybrid power generation. However, the photovoltaic and solar thermal systems operate independently, and pumping water into the solar thermal collector system at temperatures exceeding 1000°C is not feasible in engineering. Large amounts of water with uneven temperatures can cause uneven heating of the solar thermal collector system, shortening the equipment's lifespan. Furthermore, when the photovoltaic and solar thermal power generation systems operate independently, their respective online power cannot be optimized based on grid dispatch requirements.

[0010] Chinese patent CN205051623U proposes an integrated photovoltaic and solar thermal power generation system, which installs photovoltaic modules and solar thermal modules on the same bracket to achieve integrated power generation. In this system, photovoltaic and solar thermal modules still operate independently in terms of energy. Only the heat collection modules are placed on the same bracket, which is actually still independent power generation. It does not have the function of comprehensively optimizing the respective online power according to the grid scheduling needs.

[0011] In summary, there are few studies on the complementary power generation of solar thermal and photovoltaic power generation, and the research is still mainly in the theoretical stage. The relevant results cannot meet the requirements of grid dispatch for system flexibility when absorbing solar power generation. It is necessary to design a set of complementary cooperative power generation systems and operation methods that fully utilize the respective characteristics of solar thermal and photovoltaic power generation and have high self-regulation capabilities. This has not yet been mentioned in the existing patent results. Summary of the Invention

[0012] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a solar-thermal-photovoltaic complementary synergistic power generation system and operation method, which can realize the complementary synergistic power generation of photovoltaic and solar-thermal, and has strong self-regulation ability.

[0013] To achieve the above object, the hybrid solar-thermal and photovoltaic power generation system of the present invention includes a photovoltaic power station, a solar-thermal power station, an electric heating system, a busbar system, a control system and a power grid. The photovoltaic power station includes a photovoltaic array and an inverter. The solar-thermal power station includes a solar-thermal collector system, a heat storage system and a power generation system;

[0014] The output end of the photovoltaic array is connected to the power supply interface of the electric heating system and the busbar system through the inverter. The solar-thermal collector system is connected to the heat storage system. The heat storage system is connected to the power generation system. The output end of the power generation system is connected to the busbar system. The control system is connected to the control end of the busbar system. The output end of the busbar system is connected to the power grid.

[0015] The heat storage system includes a high-temperature heat storage system and a low-temperature heat storage system. Among them, the outlet of the high-temperature heat storage system is connected to the inlet of the power generation system. The outlet of the power generation system is connected to the inlet of the low-temperature heat storage system. The outlet of the low-temperature heat storage system is connected to the inlet of the solar-thermal collector system. The outlet of the solar-thermal collector system is connected to the inlet of the high-temperature heat storage system. A heater is provided in the high-temperature heat storage system. The electric heating system is connected to the heater.

[0016] The power generation system includes a heat exchanger, a steam turbine and a generator. Among them, the heat release side of the heat exchanger is connected to the heat storage system. The inlet of the heat absorption side of the heat exchanger is connected to the outlet of the steam turbine. The outlet of the heat absorption side of the heat exchanger is connected to the inlet of the steam turbine. The output shaft of the steam turbine is connected to the drive shaft of the generator.

[0017] A photovoltaic electricity meter and a solar-thermal electricity meter are provided on the busbar system. The solar-thermal electricity meter is connected to the power generation system. The photovoltaic electricity meter is connected to the inverter.

[0018] An operation method of the hybrid solar-thermal and photovoltaic power generation system includes a busbar grid connection and coordinated operation mode and a solar-thermal, photovoltaic and heat storage coordinated operation mode;

[0019] The specific operation process in the busbar grid connection and coordinated operation mode is as follows:

[0020] 1a) The control system obtains the power dispatching instruction, detects the current solar-thermal power generation power of the solar-thermal power station and the photovoltaic power generation power of the photovoltaic power station, and at the same time predicts the power generation power of the solar-thermal power station and the photovoltaic power generation power of the photovoltaic power station within a preset future time period, ensuring that the overall grid-connected power of the power station meets the requirements of the power dispatching instruction, that is, the relative deviation of the overall grid-connected power of the power station is less than the allowable deviation δ of the power grid P , that is

[0021]

[0022] Among them, G plant is the overall grid-connected power of the power station, G csp is the grid-connected power of the solar-thermal power station, Gpv is the grid-connected power of the photovoltaic power station, G grid is the power dispatch instruction, δ P The relative deviation between the overall grid-connected power of the power station and the power dispatching instruction;

[0023] 2b) Based on historical power generation data and time-of-use electricity prices, an optimization algorithm is used to optimize the time-of-use grid-connected power of the CSP and PV power plants to maximize the overall daily revenue I of the power plants.

[0024]

[0025] Among them, n is the time period into which a day is divided, G csp·t and G pv·t are the solar thermal power and photovoltaic power in the tth time period of the day, P csp·t and P pv·t They are the solar thermal power price and photovoltaic power price in the tth time period of the day, and A is the P Failure to meet grid license deviation requirements and receiving assessment fees from the electricity market;

[0026] The specific operation process of the CSP-PV heat storage coordinated operation mode is as follows:

[0027] When the power generation of the photovoltaic power station is higher than the optimized photovoltaic grid-connected power required, the remaining electric energy is used to heat the energy storage medium in the thermal storage system through the electric heating system. When the power generation of the photovoltaic power station is less than or equal to the optimized photovoltaic grid-connected power required, the electric heating system is shut down. The specific process is as follows:

[0028] Heating power G of electric heating system h It is automatically adjusted according to the photovoltaic grid-connected power and photovoltaic power generation power.

[0029]

[0030] Among them, G h is the electric heating power, G i Export electric power to the photovoltaic power station inverter;

[0031] In the process of the electric heating system heating the heat storage medium in the heat storage system, the flow of the heat storage medium entering the heat storage system is adjusted in real time, and the temperature of the heat storage medium output from the solar thermal collection system to the heat storage system is adjusted at the same time, so that the temperature of the heat storage medium output from the solar thermal collection system to the heat storage system after being heated by the electric heating system is the preset temperature, that is,

[0032]

[0033] Where c is the specific heat of the heat storage medium, is the flow rate of the heat storage medium output by the solar thermal collector system, T set is the preset temperature, T out is the temperature of the heat storage medium output by the solar thermal collector system, and η is the comprehensive efficiency of the electric heating system and the heating process.

[0034] The present invention has the following beneficial effects:

[0035] When the solar thermal - photovoltaic complementary and collaborative power generation system and its operation method according to the present invention are specifically operated, the power station can optimize the solar thermal power and photovoltaic power according to the power dispatching instructions of the power grid, combined with the current solar thermal power generation power and photovoltaic power generation power of the power station and the prediction of the solar thermal power generation power and photovoltaic power generation power in the future time period, so that the overall grid - connected power of the power station meets the power dispatching requirements, avoiding the assessment caused by the large deviation between the power generation power and the dispatching, maximizing the profit of the power station. In addition, the excess electricity of the photovoltaic power station is stored in the heat storage system through the electric heating system, enabling the deep integration of the solar thermal power station and the photovoltaic power station, eliminating the energy storage system invested by the photovoltaic power station for stable operation, further improving the economy and flexibility of the overall power station, realizing the complementary and collaborative power generation of photovoltaic and solar thermal, and having a strong self - regulation ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the schematic diagram of the present invention;

[0037] Figure 2 is the structural schematic diagram of the present invention.

[0038] Among them, 1 is the solar thermal collector system, 2 is the heat storage system, 3 is the power generation system, 4 is the bus - bar system, 5 is the photovoltaic array, 6 is the inverter, 7 is the control system, 8 is the power grid, 9 is the electric heating system, 201 is the high - temperature heat storage system, 202 is the low - temperature heat storage system, 301 is the heat exchanger, 302 is the steam turbine, 303 is the generator, 401 is the solar thermal energy meter, and 402 is the photovoltaic energy meter. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following further describes the present invention in detail with reference to the drawings:

[0040] Refer to Figure 1 and Figure 2, the hybrid solar-thermal and photovoltaic power generation system of the present invention includes a photovoltaic power station, a solar-thermal power station, an electric heating system 9, a converging system 4, a control system 7 and a power grid 8. The photovoltaic power station includes a photovoltaic array 5 and an inverter 6. The solar-thermal power station includes a solar-thermal collector system 1, a heat storage system 2 and a power generation system 3. The output end of the photovoltaic array 5 is connected to the power supply interface of the electric heating system 9 and the converging system 4 through the inverter 6. The solar-thermal collector system 1 is connected to the heat storage system 2. The heat storage system 2 is connected to the power generation system 3. The output end of the power generation system 3 is connected to the converging system 4. The control system 7 is connected to the control end of the converging system 4. The output end of the converging system 4 is connected to the power grid 8.

[0041] The heat storage system 2 includes a high-temperature heat storage system 201 and a low-temperature heat storage system 202. Wherein, the outlet of the high-temperature heat storage system 201 is communicated with the inlet of the power generation system 3. The outlet of the power generation system 3 is communicated with the inlet of the low-temperature heat storage system 202. The outlet of the low-temperature heat storage system 202 is communicated with the inlet of the solar-thermal collector system 1. The outlet of the solar-thermal collector system 1 is communicated with the inlet of the high-temperature heat storage system 201. A heater is arranged in the high-temperature heat storage system 201. The electric heating system 9 is connected to the heater.

[0042] The power generation system 3 includes a heat exchanger 301, a steam turbine 302 and a generator 303. Wherein, the heat release side of the heat exchanger 301 is communicated with the heat storage system 2. The inlet of the heat absorption side of the heat exchanger 301 is communicated with the outlet of the steam turbine 302. The outlet of the heat absorption side of the heat exchanger 301 is communicated with the inlet of the steam turbine 302. The output shaft of the steam turbine 302 is connected to the drive shaft of the generator 303.

[0043] A photovoltaic electricity meter 402 and a solar-thermal electricity meter 401 are arranged on the converging system 4. The solar-thermal electricity meter 401 is connected to the power generation system 3. The photovoltaic electricity meter 402 is connected to the inverter 6.

[0044] The operation method of the hybrid solar-thermal and photovoltaic power generation system of the present invention includes a converging and grid-connection collaborative operation mode and a solar-thermal, photovoltaic and heat storage coordinated operation mode;

[0045] The specific operation process in the converging and grid-connection collaborative operation mode is as follows:

[0046] 1a) The control system 7 obtains a power dispatching instruction, detects the current solar-thermal power generation power of the solar-thermal power station and the photovoltaic power generation power of the photovoltaic power station, and simultaneously predicts the power generation power of the solar-thermal power station and the photovoltaic power generation power of the photovoltaic power station within a preset future time period, so as to ensure that the overall grid-connection power of the power station meets the requirements of the power dispatching instruction, that is, the relative deviation of the overall grid-connection power of the power station is less than the allowable deviation δ of the power grid 8 P , that is

[0047]

[0048] Among them, G plant is the overall grid-connected power of the power station, G csp is the grid-connected power of the CSP station, G pv is the grid-connected power of the photovoltaic power station, G grid is the power dispatch instruction, δ P The relative deviation between the overall grid-connected power of the power station and the power dispatching instruction;

[0049] 2b) Based on historical power generation data and time-of-use electricity prices, an optimization algorithm is used to optimize the time-of-use grid-connected power of the CSP and PV power plants to maximize the overall daily revenue I of the power plants.

[0050]

[0051] Among them, n is the time period into which a day is divided, G csp·t and G pv·t are the solar thermal power and photovoltaic power in the tth time period of the day, P csp·t and P pv·t They are the solar thermal power price and photovoltaic power price in the tth time period of the day, and A is the P Failure to meet the grid 8 permit deviation requirements and receiving assessment fees from the electricity market;

[0052] The specific operation process of the CSP-PV heat storage coordinated operation mode is as follows:

[0053] When the power generation of the photovoltaic power station is higher than the optimized photovoltaic grid-connected power required, the remaining electric energy is used to heat the energy storage medium in the heat storage system 2 by the electric heating system 9. When the power generation of the photovoltaic power station is less than or equal to the optimized photovoltaic grid-connected power required, the electric heating system 9 is shut down. The specific process is as follows:

[0054] Heating power G of electric heating system 9 h It is automatically adjusted according to the photovoltaic grid-connected power and photovoltaic power generation power.

[0055]

[0056] Among them, G h is the electric heating power, G i Exporting electric power to the photovoltaic power station inverter 6;

[0057] During the process of the electric heating system 9 heating the heat storage medium in the heat storage system 2, the flow rate of the heat storage medium entering the heat storage system 2 is adjusted in real time, and the temperature of the heat storage medium output from the solar thermal collection system 1 to the heat storage system 2 is adjusted at the same time, so that the temperature of the heat storage medium output from the solar thermal collection system 1 to the heat storage system 2 after being heated by the electric heating system 9 is the preset temperature, that is,

[0058]

[0059] Where c is the specific heat of the heat storage medium, is the heat storage medium flow rate output by the solar thermal collector system 1, T set is the preset temperature, T out is the temperature of the heat storage medium output by the solar thermal collection system 1, and η is the comprehensive efficiency of the electric heating system 9 and the heating process.

[0060] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for operating a hybrid solar-thermal and photovoltaic power generation system, characterized in that, The above-mentioned solar thermal and photovoltaic complementary and collaborative power generation system includes a photovoltaic power station, a solar thermal power station, an electric heating system (9), a busbar system (4), a control system (7) and a power grid (8). The photovoltaic power station includes a photovoltaic array (5) and an inverter (6). The solar thermal power station includes a solar thermal collector system (1), a heat storage system (2) and a power generation system (3); The output end of the photovoltaic array (5) is connected to the power supply interface of the electric heating system (9) and the busbar system (4) through the inverter (6). The solar thermal collector system (1) is connected to the heat storage system (2). The heat storage system (2) is connected to the power generation system (3). The output end of the power generation system (3) is connected to the busbar system (4). The control system (7) is connected to the control end of the busbar system (4). The output end of the busbar system (4) is connected to the power grid (8); The heat storage system (2) includes a high-temperature heat storage system (201) and a low-temperature heat storage system (202). Among them, the outlet of the high-temperature heat storage system (201) is connected to the inlet of the power generation system (3). The outlet of the power generation system (3) is connected to the inlet of the low-temperature heat storage system (202). The outlet of the low-temperature heat storage system (202) is connected to the inlet of the solar thermal collector system (1). The outlet of the solar thermal collector system (1) is connected to the inlet of the high-temperature heat storage system (201). A heater is arranged in the high-temperature heat storage system (201). The electric heating system (9) is connected to the heater; The power generation system (3) includes a heat exchanger (301), a steam turbine (302) and a generator (303). Among them, the heat release side of the heat exchanger (301) is connected to the heat storage system (2). The inlet of the heat absorption side of the heat exchanger (301) is connected to the outlet of the steam turbine (302). The outlet of the heat absorption side of the heat exchanger (301) is connected to the inlet of the steam turbine (302). The output shaft of the steam turbine (302) is connected to the drive shaft of the generator (303); It includes a busbar connection and grid connection collaborative operation mode and a solar thermal, photovoltaic and heat storage coordinated operation mode; The specific operation process in the busbar connection and grid connection collaborative operation mode is as follows: 1a) The control system (7) obtains the power dispatching instruction, detects the solar thermal power generation of the current solar thermal power plant and the photovoltaic power generation of the photovoltaic power plant, and simultaneously predicts the power generation of the solar thermal power plant and the photovoltaic power generation of the photovoltaic power plant within a preset future time period, ensuring that the overall grid-connected power of the power plant meets the requirements of the power dispatching instruction, that is, the relative deviation of the overall grid-connected power of the power plant is less than the allowable deviation δ of the power grid (8). P , that is Among them, G plant is the grid-connected power of the whole power station, G csp is the grid-connected power of the solar thermal power station, G pv is the grid-connected power of the photovoltaic power station, G grid is the power dispatching instruction, δ P is the relative deviation between the grid-connected power of the whole power station and the power dispatching instruction; 2a) Based on the historical data of the power generation power and the time-of-use electricity price, use an optimization algorithm to optimize the time-of-use grid connection power of the solar thermal power station and the photovoltaic power station, so as to maximize the overall daily income I of the power station; Among them, n divides a day into n time periods, G csp·t and G pv·t are respectively the solar-thermal grid-connected power and the photovoltaic grid-connected power in the t-th time period of a day, P csp·t and P pv·t are respectively the solar-thermal electricity price and the photovoltaic electricity price in the t-th time period of a day. A is the penalty fee received from the power market when δ P does not meet the allowable deviation requirements of the power grid (8). The specific operation process of the solar thermal, photovoltaic and heat storage coordinated operation mode is as follows: When the power generation power of the photovoltaic power station is higher than the optimized required photovoltaic grid connection power, the remaining electric energy is used to heat the energy storage medium in the heat storage system (2) by the electric heating system (9). When the power generation power of the photovoltaic power station is less than or equal to the optimized required photovoltaic grid connection power, the electric heating system (9) is shut down. The specific process is as follows: The heating power G of the electric heating system (9) h Automatically adjusted according to the photovoltaic grid-connected power and the photovoltaic power generation power, that is Among them, G h is the electric heating power, and G i is the electric power at the outlet of the photovoltaic power station inverter (6); During the process of the electric heating system (9) heating the energy storage medium in the heat storage system (2), the flow rate of the energy storage medium entering the heat storage system (2) is adjusted in real time, and at the same time, the temperature of the energy storage medium output from the solar thermal collector system (1) to the heat storage system (2) is adjusted, so that the temperature of the energy storage medium output from the solar thermal collector system (1) to the heat storage system (2) after being heated by the electric heating system (9) is the preset temperature, that is where c is the specific heat of the heat storage medium, is the flow rate of the heat storage medium output by the solar thermal collector system (1), T set is the preset temperature, T out is the temperature of the heat storage medium output by the solar thermal collector system (1), and η is the comprehensive efficiency of the electric heating system (9) and the heating process.

2. The operation method of the photovoltaic-thermal complementary and collaborative power generation system according to claim 1, characterized in that, A photovoltaic electricity meter (402) and a solar thermal electricity meter (401) are provided on the busbar system (4). The solar thermal electricity meter (401) is connected to the power generation system (3), and the photovoltaic electricity meter (402) is connected to the inverter (6).

Images