A tower-type solar thermal and photovoltaic combined power generation system

Abstract

The present invention belongs to the technical field of solar power generation, and discloses a tower-type solar thermal and photovoltaic combined power generation system. The system includes: a transformer bank, the output side of the transformer bank is electrically connected to the power grid; a photovoltaic power generation station, the output side of the photovoltaic power generation station is electrically connected to the input side of the transformer bank; a solar thermal power generation station, the output side of the solar thermal power generation station is electrically connected to the input side of the transformer bank; a coordinated dispatching unit, which is communicatively connected to the photovoltaic power generation station and the solar thermal power generation station respectively, and is used for adjusting and distributing the load of the photovoltaic power generation station and the load of the solar thermal power generation station. By adjusting and distributing the load of the photovoltaic power generation station and the load of the solar thermal power generation station through the coordinated dispatching unit, the present invention enables the solar thermal and photovoltaic combined power generation system to have a deep peak shaving effect, optimizes the load distribution of the solar thermal and photovoltaic combined power generation system, promotes the balance of the power load, and improves the stability of the power grid operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar power generation, and particularly relates to a tower-type solar thermal and photovoltaic combined power generation system. Background Art

[0002] Solar thermal and photovoltaic are two renewable energy technologies that can both convert sunlight into electrical energy.

[0003] Among them, photovoltaic power generation is a technology that directly converts solar energy into electrical energy by using the photovoltaic effect of semiconductor materials (such as silicon). When sunlight shines on a photovoltaic cell, electrons in the cell are excited and generate an electric current, thus generating electrical energy. Photovoltaic cells can be made into panels or modules and are widely used in households, commercial buildings, and large power plants. Photovoltaic power generation has the advantages of flexible installation, simple maintenance, no noise, and zero emissions.

[0004] Solar thermal power generation is a technology that uses sunlight to transfer heat to a fluid (such as water), raises the temperature of the fluid, and then converts the thermal energy into electrical energy through a thermal cycle (such as the Rankine cycle). A solar thermal power generation system usually includes components such as a mirror field, a collector, a thermal energy storage system, and a generator set. Solar thermal power generation has the advantages of high energy conversion efficiency, large-scale development and utilization potential, and energy storage capabilities.

[0005] The amount of photovoltaic power generation is directly restricted by the solar radiation intensity, so it has obvious characteristics of generating electricity during the day and stopping at night and random uncertainty. Solar thermal power generation uses devices such as collectors to collect light resources and converts them into electrical energy through a generator, and it has good continuous adjustment capabilities. Photovoltaic and solar thermal power generation have complementary characteristics to a certain extent. Photovoltaic can only generate electricity during the day and has strong volatility, while solar thermal can suppress this characteristic and use the heat captured by its own thermal energy storage device to replace photovoltaic to continuously generate electricity at night. The two complement each other's advantages, cooperate, and perfectly solve the impact of the intermittent volatility of solar energy resources on the operation of the power grid.

[0006] During the coordinated operation of a photovoltaic and solar thermal complementary generator set and its connection to the power grid system, the power load balance degree is relatively low, and the operation stability of the power grid still needs to be improved. Summary of the Invention

[0007] The purpose of the present invention is to provide a tower-type solar thermal and photovoltaic combined power generation system to solve the problem that during the coordinated operation of an existing photovoltaic and solar thermal complementary generator set and its connection to the power grid system, the power load balance degree is relatively low, and the operation stability of the power grid still needs to be improved.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] The present invention provides a tower-type solar thermal and photovoltaic combined power generation system, and the system includes:

[0010] A transformer bank, the output side of which is electrically connected to the power grid;

[0011] A photovoltaic power station, the output side of which is electrically connected to the input side of the transformer bank;

[0012] A solar thermal power station, the output side of which is electrically connected to the input side of the transformer bank;

[0013] A coordinated dispatching unit, which is communicatively connected to the photovoltaic power station and the solar thermal power station respectively, and is used for adjusting and distributing the load of the photovoltaic power station and the load of the solar thermal power station.

[0014] Preferably, the system further includes: a common AC bus, and the output side of the photovoltaic power station, the output side of the solar thermal power station and the input side of the transformer bank are all electrically connected to the common AC bus.

[0015] Preferably, the photovoltaic power station includes: a plurality of photovoltaic arrays, a DC bus, an inverter bank and a photovoltaic transformer;

[0016] The output ends of each photovoltaic array are all electrically connected to the DC bus, the input end of the inverter bank is electrically connected to the DC bus, the output end of the inverter bank is electrically connected to the input end of the photovoltaic transformer, and the output end of the inverter is electrically connected to the common AC bus.

[0017] Preferably, the solar thermal power station includes:

[0018] A tower-type mirror field, which is used for focusing sunlight to convert solar radiant energy into heat energy;

[0019] A heat storage tank, which is used for storing the heat energy generated by the tower-type mirror field;

[0020] A steam turbine unit, which is used for converting the heat energy generated by the tower-type mirror field or the heat energy stored in the heat storage tank into mechanical energy;

[0021] A generator, which is connected to the steam turbine unit in a transmission manner, and is used for converting the mechanical energy output by the steam turbine unit into electrical energy;

[0022] A solar thermal transformer, the input end of which is electrically connected to the electrical energy output end of the generator, and the output end of which is electrically connected to the common AC bus.

[0023] Preferably, the coordinated dispatching unit includes:

[0024] A meteorological prediction module, which is used for predicting the meteorological data of the target area in the future time period, and the target area is the area where the photovoltaic power station and the solar thermal power station are located;

[0025] A power generation load prediction module, which is used to predict the power generation load prediction value based on the meteorological data of the target area in the future time period, and the power generation load prediction value includes: the load prediction value of the photovoltaic power station and the load prediction value of the solar thermal power station;

[0026] A load distribution module, which is used to distribute the power generation load prediction value to obtain the deep peak shaving results of the photovoltaic power station and the solar thermal power station.

[0027] Preferably, the power generation load prediction module is specifically used for:

[0028] Based on a preset correlation algorithm, select a historical time period similar to the meteorological data of the target area in the future time period;

[0029] Obtain the load historical data of the historical time period, and construct a sample set with the load historical data and meteorological data of the historical time period;

[0030] Train the load prediction model based on the sample set to obtain a trained load prediction model;

[0031] Input the meteorological data of the future time period into the trained load prediction model to obtain the power generation load prediction value.

[0032] Preferably, the load distribution module is specifically used for:

[0033] Construct decision variables based on the power generation load prediction value, and construct a deep peak shaving load distribution function for the photovoltaic power station and the solar thermal power station based on the decision variables;

[0034] Construct the constraint conditions of the decision variables;

[0035] Based on the optimization algorithm, use the constraint conditions as the constraint terms to iteratively optimize the deep peak shaving load distribution function to obtain the optimal power generation load distribution, and use the optimal power generation load distribution as the deep peak shaving results of the photovoltaic power station and the solar thermal power station.

[0036] Preferably, the system further includes: a reactive power compensation unit, and the reactive power compensation unit includes: a compensation module and a compensation control module, and the compensation module is communicatively connected to the compensation control module; the compensation module includes: a first reactive power compensation device and a second reactive power compensation device;

[0037] The first reactive power compensation device is used to distribute reactive power to the photovoltaic power station, and the second reactive power compensation device is used to distribute reactive power to the solar thermal power station;

[0038] The compensation control module is configured to: when the coordinated scheduling unit adjusts and distributes the loads of the photovoltaic power station and the solar thermal power station, collect the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment; determine the total reactive power compensation amount according to the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment; distribute the total reactive power compensation amount based on a preset algorithm to obtain the reactive power compensation amount of the photovoltaic power station and the reactive power compensation amount of the solar thermal power station; generate a photovoltaic reactive power compensation control command and a solar thermal reactive power compensation control command respectively based on the reactive power compensation amount of the photovoltaic power station and the reactive power compensation amount of the solar thermal power station; send the generated photovoltaic reactive power compensation control command and solar thermal reactive power compensation control command to the first reactive power compensation device and the second reactive power compensation device respectively; when the first reactive power compensation device executes the photovoltaic reactive power compensation control command, compensate the reactive power of the photovoltaic power station with the reactive power compensation amount of the photovoltaic power station; when the second reactive power compensation device executes the solar thermal reactive power compensation control command, compensate the reactive power of the solar thermal power station with the reactive power compensation amount of the solar thermal power station.

[0039] Preferably, the compensation module further includes: a third reactive power compensation device, which is configured to distribute reactive power to the AC bus;

[0040] The compensation control module is further configured to: determine whether the total reactive power compensation amount exceeds a preset compensation amount, where the preset compensation amount is determined according to the compensation upper limit value of the first reactive power compensation device and the compensation upper limit value of the second reactive power compensation device; when the total reactive power compensation amount exceeds the preset compensation amount, determine the compensation difference between the total reactive power compensation amount and the preset compensation amount, generate a bus reactive power compensation control command based on the compensation difference, and send the bus reactive power compensation control command to the third reactive power compensation device, and when the third reactive power compensation device executes the bus reactive power compensation control command, compensate the reactive power of the AC bus with the compensation difference.

[0041] Preferably, the preset algorithm is a genetic algorithm.

[0042] Beneficial effects:

[0043] In the present invention, the coordinated scheduling unit adjusts and distributes the loads of the photovoltaic power station and the solar thermal power station, so that the solar thermal and photovoltaic combined power generation system has a deep peak shaving effect, optimizes the load distribution of the solar thermal and photovoltaic combined power generation system, promotes the balance of the power load, and improves the stability of the power grid operation. Description of the Drawings

[0044] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0045] Figure 1 It is the overall framework block diagram of the tower - type solar thermal and photovoltaic combined power generation system provided by an embodiment of the present invention. Specific embodiments

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the accompanying drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the drawings is only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. It should be noted here that the description of these embodiment modes is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0047] Figure 1 It is the overall framework block diagram of the tower - type solar thermal and photovoltaic combined power generation system provided by an embodiment of the present invention. As Figure 1 shown, this embodiment provides a tower - type solar thermal and photovoltaic combined power generation system, and the system includes: a power grid, a transformer bank, a photovoltaic power generation station, a solar thermal power generation station, and a coordinated dispatching unit;

[0048] Among them, the output side of the transformer bank is electrically connected to the power grid, the output side of the photovoltaic power generation station is electrically connected to the input side of the transformer bank, the output side of the solar thermal power generation station is electrically connected to the input side of the transformer bank, and the coordinated dispatching unit is respectively communicatively connected to the photovoltaic power generation station and the solar thermal power generation station, and is used to adjust and distribute the loads of the photovoltaic power generation station and the solar thermal power generation station.

[0049] In this embodiment, by arranging a coordinated dispatching unit in the solar thermal and photovoltaic combined power generation system, the coordinated dispatching unit is used to adjust and distribute the loads of the photovoltaic power generation station and the solar thermal power generation station, so that the solar thermal and photovoltaic combined power generation system has a deep peak - shaving effect, optimizes the load distribution of the solar thermal and photovoltaic combined power generation system, promotes the balance of the power load, and improves the stability of the power grid operation.

[0050] As a further optimization of this embodiment, the system further includes: a common AC bus, and the output sides of the photovoltaic power generation station, the solar thermal power generation station, and the input side of the transformer bank are all electrically connected to the common AC bus.

[0051] In this embodiment, the photovoltaic power generation station includes: a plurality of photovoltaic arrays, a DC bus, an inverter group, and a photovoltaic transformer;

[0052] The output terminals of each photovoltaic array are electrically connected to the DC bus, the input terminals of the inverter group are electrically connected to the DC bus, the output terminals of the inverter group are electrically connected to the input terminals of the photovoltaic transformer, and the output terminals of the inverter are electrically connected to the common AC bus.

[0053] In this embodiment, each photovoltaic array converts solar energy into electrical energy. The DC power output by all photovoltaic arrays is transmitted to the inverter through the DC bus. The DC power is converted into AC power by the inverter, boosted by the photovoltaic transformer, and then incorporated into the AC bus.

[0054] In this embodiment, the solar thermal power station includes: a tower mirror field, a heat storage tank, a steam turbine unit, a generator, and a solar thermal transformer;

[0055] The tower mirror field is used to focus sunlight to convert solar radiant energy into heat energy, exchange heat with the heat exchanger of the steam turbine unit to generate steam, and use the steam to drive the steam turbine to work and drive the generator to generate electricity;

[0056] The heat storage tank is used to store the heat energy generated by the tower mirror field. When the solar radiation intensity is high, a part of the heat energy can be stored in the heat storage tank. When it is night, the heat energy in the heat storage tank is used to generate steam, and then power generation is realized;

[0057] The steam turbine unit is used to convert the heat energy generated by the tower mirror field or the heat energy stored in the heat storage tank into mechanical energy; the generator is connected to the steam turbine by transmission and is used to convert the mechanical energy output by the steam turbine unit into electrical energy;

[0058] The input terminal of the solar thermal transformer is electrically connected to the electrical energy output terminal of the generator, and the output terminal of the solar thermal transformer is electrically connected to the common AC bus.

[0059] In this embodiment, the electrical energy output by the generator is boosted by the solar thermal transformer so that the voltage output by the solar thermal transformer is kept consistent with the voltage output by the photovoltaic transformer, and then incorporated into the AC bus. Then, the transformer group performs secondary boosting on the voltage of the AC bus, and the AC power after secondary boosting is incorporated into the power grid.

[0060] As a further optimization of this embodiment, the collaborative scheduling unit includes: a meteorological prediction module, a power generation load prediction module, and a load distribution module;

[0061] The meteorological prediction module is used to predict the meteorological data in the target area in the future period. The target area is the area where the photovoltaic power station and the solar thermal power station are located. The meteorological prediction module can be a meteorological station arranged in the target area, and the meteorological station is used to predict the meteorological data in the future period. The meteorological data includes: temperature, air pressure, humidity, wind speed, wind direction, precipitation, sunshine hours, radiation amount, visibility, and surface temperature;

[0062] The power generation load prediction module is used to predict the power generation load prediction value based on the meteorological data of the target area in the future period. The power generation load prediction value includes: the load prediction value of the photovoltaic power station and the load prediction value of the solar thermal power station;

[0063] The load distribution module is used to distribute the power generation load prediction value to obtain the deep peak shaving results of the photovoltaic power station and the solar thermal power station.

[0064] Specifically, the power generation load prediction module is specifically used for: based on a preset correlation algorithm, selecting a historical period similar to the meteorological data of the future period of the target area; obtaining the load historical data of the historical period, and constructing a sample set with the load historical data and meteorological data of the historical period; training the load prediction model based on the sample set to obtain a trained load prediction model; inputting the meteorological data of the future period into the trained load prediction model to obtain the power generation load prediction value.

[0065] In this embodiment, the preset correlation algorithm can be the grey correlation analysis method. The grey correlation analysis method quantifies the correlation degree between various factors in the system by comparing the "grey correlation degree" between them; in this embodiment, taking a certain day in the future as an example, the grey correlation analysis method is used to find similar days with meteorological data similar to a certain day in the future from the past month (or several months), and each similar day is used as a historical period; then the load historical data of each hour of each day in the historical period (including the load data of the photovoltaic power station and the photovoltaic data of the solar thermal power station) is counted, and then a sample set is constructed with the load historical data and meteorological data of the historical period, and the sample set is used as the training set. The load prediction model in this embodiment can be a random forest model. After completing the training of the random forest model, the meteorological data of a certain day in the future is input into the random forest model, and the output result of the decision tree in the random forest model can be obtained, and the output result of the decision tree is used as the power generation load prediction value.

[0066] After the solar thermal and photovoltaic combined power generation system is connected to the grid for operation, since the photovoltaic power station only supports power generation during the day and depends on the solar thermal power station for continuous power generation at night, there is a large load peak-valley difference between the two. In order to improve the flexible operation degree of the power system; then after obtaining the power generation load prediction value, it is necessary to distribute it to obtain the best deep peak shaving result, thereby weakening the equivalent load peak-valley difference.

[0067] Specifically, the load distribution module is specifically used for: constructing decision variables based on the power generation load prediction value, constructing a deep peak shaving load distribution function for the photovoltaic power station and the solar thermal power station based on the decision variables; constructing the constraint conditions of the decision variables; based on the optimization algorithm, using the constraint conditions as the constraint terms, iteratively optimizing the deep peak shaving load distribution function to obtain the optimal power generation load distribution, and using the optimal power generation load distribution as the deep peak shaving result of the photovoltaic power station and the solar thermal power station.

[0068] In this embodiment, the expression of the deep peak shaving load distribution function is as follows:

[0069]

[0070] In the formula, F is the deep peak shaving load distribution function, T is the total number of time periods for the dispatching of the solar thermal and photovoltaic combined power generation system, i is the i-th time period. In this embodiment, one day is used as the peak shaving cycle, and each time period is one hour; is the grid power supply output at time t, is the average value of the grid power supply output in a day, G k is a decision variable.

[0071] Among them, the calculation expression of the average value of the grid power supply output in a day is:

[0072]

[0073] In this embodiment, the constraint conditions include: the output limit constraint of the photovoltaic power station, the output limit constraint of the solar thermal power station, the capacity constraint of the energy storage tank, and the heat storage and heat release power constraint of the energy storage tank, etc.; the optimization algorithm of this embodiment can be a particle swarm algorithm, a genetic algorithm, a grey wolf algorithm, etc. The deep peak shaving load distribution function of the photovoltaic power station and the solar thermal power station is solved by using the optimization algorithm, and the global optimal solution of the deep peak shaving load distribution function is the optimal peak shaving load distribution result.

[0074] In this embodiment, by constructing the deep peak shaving load distribution function of the photovoltaic power station and the solar thermal power station, and using the deep peak shaving load distribution function to distribute the load of the photovoltaic power station and the solar thermal power station, it has the effect of deep peak shaving, the peak shaving and valley filling effect is relatively significant, the load distribution is optimized, and the power load balance is promoted.

[0075] As a further optimization of this embodiment, the system further includes: a reactive power compensation unit, the reactive power compensation unit includes: a compensation module and a compensation control module, and the compensation module is communicatively connected to the compensation control module; the compensation module includes: a first reactive power compensation device and a second reactive power compensation device;

[0076] The first reactive power compensation device is used to distribute reactive power to the photovoltaic power station, and the second reactive power compensation device is used to distribute reactive power to the solar thermal power station.

[0077] In this embodiment, when the coordinated dispatching unit adjusts and distributes the load of the photovoltaic power station and the load of the solar thermal power station, it will indirectly cause voltage fluctuations in the power grid and affect the operation of the power grid; in order to reduce the impact on the power grid; this embodiment uses the reactive power compensation method to adjust the voltage output by the solar thermal and photovoltaic combined power generation system to ensure the stability of the power grid operation.

[0078] However, there are certain differences in the voltage stability levels between solar thermal power plants and photovoltaic power plants. Compensating reactive power separately for solar thermal power plants and photovoltaic power plants is inconsistent and complex, and it cannot guarantee the voltage regulation accuracy requirements of the entire system.

[0079] As a further optimization of this embodiment, the compensation control module is configured to: when the coordinated dispatching unit adjusts and distributes the loads of the photovoltaic power plant and the solar thermal power plant, collect the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment; determine the total reactive power compensation amount according to the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment; distribute the total reactive power compensation amount based on a preset algorithm to obtain the reactive power compensation amount of the photovoltaic power plant and the reactive power compensation amount of the solar thermal power plant; generate a photovoltaic reactive power compensation control command and a solar thermal reactive power compensation control command respectively based on the reactive power compensation amount of the photovoltaic power plant and the reactive power compensation amount of the solar thermal power plant; send the generated photovoltaic reactive power compensation control command and solar thermal reactive power compensation control command to the first reactive power compensation device and the second reactive power compensation device respectively; when the first reactive power compensation device executes the photovoltaic reactive power compensation control command, compensate the reactive power of the photovoltaic power plant with the reactive power compensation amount of the photovoltaic power plant; when the second reactive power compensation device executes the solar thermal reactive power compensation control command, compensate the reactive power of the solar thermal power plant with the reactive power compensation amount of the solar thermal power plant.

[0080] In this embodiment, by constructing an AC bus and monitoring the voltage change of the AC bus in real time, the total reactive power compensation amount can be calculated according to the voltage change of the AC bus. The calculation expression of the total reactive power compensation amount in this embodiment is:

[0081]

[0082] In the formula, Q ref is the total reactive power compensation amount, U0 is the reference voltage of the power grid, U2 is the AC bus voltage at the current moment, U1 is the AC bus voltage at the historical moment, Q2 is the reactive power of the AC bus at the current moment, and Q1 is the reactive power of the AC bus at the historical moment; in this embodiment, the AC bus voltage at the historical moment is determined according to the sampling period T s For example, if the T s moment is the current moment, then the historical moment is the T s-1 moment.

[0083] In this embodiment, the first reactive power compensation device can be an inverter of a photovoltaic power station or an independently added SVC (Static Var Compensator) reactive power regulator; the second reactive power compensation device can be a generator or an independently added SVC reactive power regulator; preferably, both the first reactive power compensation device and the second reactive power compensation device are independently added SVC reactive power regulators to reduce the impact on the entire system.

[0084] In this embodiment, the preset algorithm can be a genetic algorithm. When allocating the total reactive power compensation amount based on the preset algorithm, it is necessary to construct an allocation objective function for reactive power compensation. The expression of the allocation objective function for reactive power compensation in this embodiment is:

[0085] Y = αY1 + βY2;

[0086] In the formula, Y is the allocation objective function for reactive power compensation, Y1 is the objective function for stabilizing the reactive power compensation voltage, Y2 is the objective function for network loss, α is the weight coefficient of the objective function for stabilizing the reactive power compensation voltage, and β is the weight coefficient of the objective function for network loss.

[0087] Among them, the expression of the objective function for stabilizing the reactive power compensation voltage is:

[0088] Y1 = min(f1 + f2);

[0089] In the formula, f1 is the AC bus voltage function, and f2 is the DC bus voltage function.

[0090] Among them, f1 = (U1 - U ref ) 2 , f2 = (U pv - U ref ) 2 + (U csp - U ref ) 2 , U pv is the DC bus voltage, and U csp is the output voltage of the solar thermal power station.

[0091] Among them, the expression of the objective function for network loss is:

[0092] Y2 = minP k ;

[0093] In the formula, P k is the network loss of the solar thermal and photovoltaic combined power generation system.

[0094] In this embodiment, the constraint terms of the allocation objective function for reactive power compensation include: power flow equation constraint, DC bus voltage constraint, and AC bus voltage constraint.

[0095] In this embodiment, based on the genetic algorithm, by solving the constraint terms of the distribution objective function for reactive power compensation, the distribution objective function for reactive power compensation can be solved, and the optimal reactive power compensation amount of the photovoltaic power station and the reactive power compensation amount of the solar thermal power station can be obtained.

[0096] By performing reactive power compensation on the photovoltaic power station and the solar thermal power station through the above method, better control effects can be achieved, the network loss of the power generation system is relatively low, the voltage distribution within the station is improved, the safe operation of the equipment within the station is ensured, the impact on the power grid is reduced, and the operation stability of the power grid is improved.

[0097] As a further optimization of this embodiment, the compensation module further includes: a third reactive power compensation device, which is used to distribute reactive power to the AC bus.

[0098] The compensation control module is further used for: judging whether the total reactive power compensation amount exceeds a preset compensation amount, where the preset compensation amount is determined according to the compensation upper limit value of the first reactive power compensation device and the compensation upper limit value of the second reactive power compensation device; when the total reactive power compensation amount exceeds the preset compensation amount, determining the compensation difference between the total reactive power compensation amount and the preset compensation amount, generating a bus reactive power compensation control command based on the compensation difference, and sending the bus reactive power compensation control command to the third reactive power compensation device. When the third reactive power compensation device executes the bus reactive power compensation control command, it compensates the reactive power of the AC bus with the compensation difference.

[0099] In this embodiment, the third reactive power compensation device is an independently added SVC reactive power regulator. The preset compensation amount can be 80% of the sum of the compensation upper limit value of the first reactive power compensation device and the compensation upper limit value of the second reactive power compensation device. That is, after exceeding 80% of the sum of the compensation upper limit value of the first reactive power compensation device and the compensation upper limit value of the second reactive power compensation device, it indicates that through the adjustment within the station, the rapid response to the power grid fluctuation cannot be achieved. At this time, the third reactive power compensation device directly compensates the reactive power of the AC bus, which can quickly reduce the voltage fluctuation and reduce the impact on the power grid.

[0100] The above are only embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A tower-type solar thermal and photovoltaic combined power generation system, characterized in that: The system comprises: A transformer group, wherein the output side of the transformer group is electrically connected to the power grid; A photovoltaic power station, wherein the output side of the photovoltaic power station is electrically connected to the input side of the transformer group; A solar thermal power station, wherein the output side of the solar thermal power station is electrically connected to the input side of the transformer group; The coordinated dispatching unit is respectively connected to the photovoltaic power station and the solar thermal power station for adjusting and distributing the load of the photovoltaic power station and the load of the solar thermal power station; The system further comprises: an AC bus, to which the output side of the photovoltaic power station, the output side of the solar thermal power station and the input side of the transformer group are all electrically connected; The collaborative scheduling unit comprises: The weather forecast module is used to predict the weather data of the target area in the future period. The target area is the area where the photovoltaic power station and the solar thermal power station are located. The weather data includes: temperature, air pressure, humidity, wind speed, wind direction, precipitation, sunshine hours, radiation, visibility and surface temperature; The power generation load prediction module is used to predict the power generation load prediction value based on the meteorological data of the target area in the future period, and the power generation load prediction value includes: the load prediction value of the photovoltaic power station and the load prediction value of the solar thermal power station; the power generation load prediction module is specifically used to: based on the preset association algorithm, select the historical time period similar to the meteorological data of the future period of the target area; obtain the load history data of the historical time period, and construct a sample set with the load history data and meteorological data of the historical time period; train the load prediction model based on the sample set to obtain the trained load prediction model; input the meteorological data of the future period into the trained load prediction model to obtain the power generation load prediction value; wherein the preset association algorithm is the gray association analysis method, and the gray association analysis method is used to find similar days in the past month that are similar to the meteorological data of the future day, and each similar day is used as the historical period, and the load history data of each hour of each day in the historical period is counted, and the sample set is constructed with the load history data and meteorological data of the historical period; The load distribution module is used to distribute the predicted value of power generation load and obtain the deep peak regulation results of photovoltaic power stations and solar thermal power stations; The load distribution module is specifically used for: Decision variables are constructed based on the predicted value of power generation load, and the deep peak load allocation function of photovoltaic power station and solar thermal power station is constructed based on the decision variables; Construct constraints on decision variables; Based on the optimization algorithm, the deep peak load distribution function is iteratively optimized with the constraint conditions as the constraint items to obtain the optimal power generation load distribution, which is used as the deep peak load distribution result of the photovoltaic power station and the solar thermal power station. The expression of the deep peak load distribution function is: ； Where F is the deep peak load allocation function, T is the total number of time periods for the solar thermal and photovoltaic combined power generation system, i is the i-th time period, The power output of the power grid during period t, is the average power output of the power grid in a day. is the decision variable; Among them, the calculation expression of the average value of the power supply output of the power grid in a day is: ； Among them, the constraints include: photovoltaic power station output limit constraint, solar thermal power station output limit constraint, energy storage tank capacity constraint and energy storage tank heat storage and heat release power constraint; The system further comprises: a reactive power compensation unit, the reactive power compensation unit comprising: a compensation module and a compensation control module, the compensation module being communicatively connected with the compensation control module; the compensation module comprising: a first reactive power compensation device and a second reactive power compensation device; The first reactive power compensation device is used to allocate reactive power to the photovoltaic power station, and the second reactive power compensation device is used to allocate reactive power to the solar thermal power station; The compensation control module is used to: collect the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment when the coordinated dispatching unit adjusts and distributes the load of the photovoltaic power station and the load of the solar thermal power station; determine the total reactive power compensation amount according to the reference voltage of the power grid, the AC bus voltage at the current moment, and the AC bus voltage at the historical moment; distribute the total reactive power compensation amount based on a preset algorithm to obtain the reactive compensation amount of the photovoltaic power station and the reactive compensation amount of the solar thermal power station; and distribute the reactive power compensation amount based on the reactive compensation amount of the photovoltaic power station and the reactive compensation amount of the solar thermal power station. The reactive compensation amount of the power station generates photovoltaic reactive compensation control instructions and solar thermal reactive compensation control instructions respectively; the generated photovoltaic reactive compensation control instructions and solar thermal reactive compensation control instructions are sent to the first reactive compensation device and the second reactive compensation device respectively; when the first reactive compensation device executes the photovoltaic reactive compensation control instruction, it compensates the reactive power of the photovoltaic power station with the reactive compensation amount of the photovoltaic power station; when the second reactive compensation device executes the solar thermal reactive compensation control instruction, it compensates the reactive power of the solar thermal power station with the reactive compensation amount of the solar thermal power station; The compensation module further comprises: a third reactive power compensation device, the third reactive power compensation device being used to distribute reactive power to the AC bus; The compensation control module is also used to: determine whether the total reactive power compensation amount exceeds a preset compensation amount, the preset compensation amount is determined according to the compensation upper limit value of the first reactive compensation device and the compensation upper limit value of the second reactive compensation device; when the total reactive power compensation amount exceeds the preset compensation amount, determine the compensation difference between the total reactive power compensation amount and the preset compensation amount, generate a bus reactive compensation control instruction based on the compensation difference, send the bus reactive compensation control instruction to the third reactive compensation device, and the third reactive compensation device compensates the reactive power of the AC bus with the compensation difference when executing the bus reactive compensation control instruction; The third reactive power compensation device is a separately added SVC reactive power controller, and the preset compensation amount may be 80% of the sum of the compensation upper limit value of the first reactive power compensation device and the compensation upper limit value of the second reactive power compensation device.

2. The tower type solar thermal and photovoltaic combined power generation system according to claim 1 is characterized in that: The photovoltaic power station comprises: a plurality of photovoltaic arrays, a DC bus, an inverter group and a photovoltaic transformer; The output end of each photovoltaic array is electrically connected to the DC bus, the input end of the inverter group is electrically connected to the DC bus, the output end of the inverter group is electrically connected to the input end of the photovoltaic transformer, and the output end of the inverter is electrically connected to the AC bus.

3. The tower type solar thermal and photovoltaic combined power generation system according to claim 1, characterized in that: The solar thermal power station comprises: A tower field of mirrors used to focus sunlight to convert solar radiation into heat; Heat storage tank, used to store the heat energy generated by the tower mirror field; A steam turbine unit for converting the thermal energy generated by the tower mirror field or the thermal energy stored in the thermal storage tank into mechanical energy; The generator is connected to the steam turbine drive and is used to convert the mechanical energy output by the steam turbine unit into electrical energy; A photothermal transformer, wherein the input end of the photothermal transformer is electrically connected to the power output end of the generator, and the output end of the photothermal transformer is electrically connected to the AC bus.

4. The tower type solar thermal and photovoltaic combined power generation system according to claim 1, characterized in that: The preset algorithm is a genetic algorithm.

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