Research on optimal dispatching strategy of solar thermal-photovoltaic-wind combined power generation system

New energy photovoltaic generation of electricity and wind power have developed rapidly, and the installed capacity has been increasing, but their volatility and randomness have also caused a certain impact on the power grid. Considering that solar thermal power generation and photovoltaic power generation have natural complementary advantages, and solar thermal power generation and power output of wind power can complement each other in time., this paper proposes an optimal scheduling strategy for solar thermal-photovoltaic-wind alliance power generation system, which uses thermal storage device of the heat power station of solar energy to cope with the problem of wind and light abandonment of new energy power generation and promote the consumption level of renewable energy. The economic and stability deviations of the system before and in the launch the solar thermal power station are compared in depth and the simulation is verified in the IEEE30 node system. The results show that after the introduction of solar thermal power (CSP) station in the combined power generation system, the economy of the scientific is remarkable improvement, the wind turbine is also reduced, which realizes the full absorption of new energy.


Introduction
With the world climate shift becoming more and more serious, at the same time, the growing energy demand, we are now paying more and more attention to new energy.A variety of renewable energy such as solar thermal, photovoltaic, and wind power have broad market prospects and application potential.However, these energy sources are insufficient in some cases, such as photovoltaic night power failure, wind and wind speed instability, etc. Solar thermal energy uses the heat radiated by the solar energy and converts it into heat energy through collectors, it is used to heat water or generate steam to drive generators.In contrast, photovoltaic energy uses semiconductor materials to absorb photon energy and convert it into electricity.Although the efficiency and technological maturity of solar thermal, photovoltaic and wind power have been significantly improved, they still have some limitations under certain conditions.For the above question, this paper put forward an innovative photothermalphotovoltaic-wind hybrid power generation system.The system combines solar thermal, photovoltaic and wind power, leveraging their complementary features to enhance energy conversion efficiency and stability.Specifically, photothermal energy can convert excess thermal energy into heat storage through heat storage systems for use at night or when there is not enough light.At the same time, photovoltaic and wind energy can continuously power the system at night or when there is not enough light.This cogeneration system maximizes the use of solar and wind resources by optimizing energy distribution and allocation, while maintaining a stable supply of energy.
In recent years, domestic and foreign research on photothermal-photovoltaic-wind combined power generation has been extensive.The Electric power setup building of our country is gradually moving towards intellectualization and strong adaptability.Meanwhile, the supplementary preponderances of solar-thermal and wind power resources are steadily acknowledged, yet a number of researchers began to pay attention to the mutually furnish of various renewable energy sources.Under this background, photothermal-photovoltaic-wind compound produce electricity has grow into a study focus.A multienergy system economic dispatch model on account of a genetic algorithm is proposed, with the goal of maximizing system benefits, while considering the complementarity between solar thermal energy, photovoltaic and wind power, to achieve efficient energy utilization [1].Rui et al. [2] used a multiobjective optimization algorithm for joint scheduling of photovoltaic, wind and CSP resources with constraints to minimize the total cost and emissions, and obtained the optimal solution for economy and environmental protection.In the integration of photovoltaic, wind and thermal energy storage systems, the DPSO is used to optimize the scheduling strategy, and factors such as electricity price fluctuation and load change are taken into account to maximize the system benefit [3].Kueh K and Nathan G [4] combined wind, pump energy storage and CSP systems, on the basis of multi-objective optimization methods, comprehensively considering power generation costs, water supply quality and energy utilization efficiency, to achieve coordinated operation and optimal configuration of the system.Internationally, Chen et al. [5] proposed a collaborative optimization framework for photovoltaic, wind power and energy storage in the context of integrated energy systems.By establishing an optimization model with multiple constraints, the collaborative operation and optimal scheduling between multiple energy sources are realized.Jing et al. [6] combined wind, photovoltaic and solar thermal energy to propose a unified scheduling method based on supply and demand matching.By establishing the matching relationship between energy supply and demand, the system scheduling strategy is optimized to maximize energy utilization efficiency.Based on the combined power generation system of wind power, photovoltaic and solar thermal energy, a comprehensive optimal dispatching strategy is proposed [7].By determining the best system capacity and power distribution, system economy and reliability are achieved.By considering the changing characteristics of wind, photovoltaic and solar thermal energy, combined with a multi-objective fire-water complementary dispatching strategy, the energy optimization and benefit maximization of the hybrid-power-generation system are realized [8].
In summary, domestic and foreign studies have realized the importance of optimal scheduling strategies on solar-heat-photovoltaic-wind [9] combined power generation systems, and explored and optimized them through different methods and technologies.Such studies typically focus on aspects such as energy economics, reliability and environmental benefits, with the aim of maximizing synergies and energy efficiency between multiple energy sources.Although some achievements have been made, there are still challenges in practical application and system complexity, which require further in-depth research and improvement.Future research can focus on the scheduling methods, energy storage technology and intelligent control of CSP-photovoltaic-wind interconnected power systems to promote the development and application of this field.

Photothermal-photovoltaic-wind combined power generation system
The structure of the CSP-PV-wind energy combined power generation system is composed of a CSP electronic system, a photovoltaic electronic system and a wind power electronic system, which cooperate with each other to realize the complementary utilization of a variety of energy sources.Figure 1 below shows the basic structure of the system: Photothermal electronic system: the optothermal sub-system is constituted of three parts: heat store system (TES), light field (SF), with thermoelectric conversion module (PB).Collectors are used to focus, absorb and convert solar radiant heat into high-temperature thermal energy.Heat conduction media conducts and stores heat by conduction.Heat storage systems are used to store and dispatch heat energy, and can include equipment such as hot and cold tanks, heat accumulators, etc.Power generation systems [10] use stored heat energy to heat water into steam and drive turbines from steam to generate electricity.
Photovoltaic electronic system: The photovoltaic electronic system uses photovoltaic panels to convert the light energy radiated by the sun into DC electricity.The system consists of photovoltaic modules, inverters, battery packs and electronic control systems.
Wind power subsystem: The generator converts mechanical energy into electrical energy and outputs it to the grid through an electronic control system.
In a combined photothermal-photovoltaic-wind power generation system, these subsystems can cooperate and complement each other.For example, if a photothermal subsystem produces more heat than needed during a clear day, the excess thermal energy can be used to heat water or steam and convert it into electricity.Similarly, if photovoltaic and wind subsystems produce more energy than demand, the excess energy can be used for heat storage or other purposes in the photothermal subsystem.This cogeneration system enables the efficient use of multiple energy sources and increases the flexibility and sustainability of energy production.

Combined power generation system goal function
The optimized objective of the CSP-PV-Wind unite energy system [11] is to minimize the minimize cost, yet this premise of setting up the objective function is to consider the wind power curtailment penalty, solar thermal generator set operating cost, PV power station operating cost and thermal power unit operating cost.The hybrid power generation system's objective function is as follows: ( ) where C represents the total operating cost of the combined generation system, and 1 E is the cost of curtailment penalties, as follows: where T represents the optimized operating time of the system, w a is the wind power curtailment penalty coefficient, and wloss,t P is the curtailment force of wind power call into being to t moment.

2
E act for operation and maintenance cost of the photovoltaic plant as follows: where T stands this optimized mobile time in this method, PV a is the cost factor of solar photovoltaic energy generation, , PV t P is output rating of the photovoltaic genset at time t.
3 E is the power generation cost of thermal power units, as follows: where T represents the system optimization running time, N is the number of system units, i a is the output cost paramenter in the ith conventional unit, and , i t P is rated output to this ith traditional unit at t.

4
E express the operation and maintenance cost of the CSP station, and the operation and maintenance cost of solar thermal and the output power can also be regarded as linear, as follows: ( )

Restraints
This restraints of the CSP-PV-Wind hybrid motor system basically take into account the correlation limitation of solar thermal power plants, photovoltaic power generation, wind power reduction restrictions, operation constraints of traditional units, as well as ascending limitations.
(1) Restrictive factors are connected with solar thermal power plants Running limit and climbing constraints of solar thermal units:

Arithmetic analysis
This article uses the IEEE-30 points structure as this emulation institution to analyze the operating characteristics of the CSP-PV-Wind hybrid power system and the operation peculiarity of the power grid after the solar thermal power station is combined with the grid.Figure 2 below shows the IEEE-30 node system diagram, replacing the original units 2, 3 and 4 with photovoltaic power stations, solar thermal power stations and wind turbines.The simulation study will be divided into two scenarios: photothermal power station are not introduced into the system (Scenario 1), the system introduces a solar collector (scenario 2).The planned load profile for the region is shown in Figure 3, and Figure 4 shows the combination of solar radiation strength, estimated photovoltaic output and wind turbine force,among which the data of photothermal power plant and solar irradiance strength originated from SAM software.The purpose of this study is to optimize the model by calling the optimization model software CPLEX with the Yalmip toolbox in Matlab.After the optimization of the system, the yield of No. 1, 5 and 6 the figure below shows the thermal unit power in the IEEE-30 node .As we can see from the diagram, before and after the leading-in the solar thermal power plants, the output of the conventional power unit changes: since the bring in the solar thermal energy station, No. 1 unit no more joins in peak shaving during the peak period of electricity consumption, the output of No. 5 unit is slowed down during the illuminance and the output period of the heliacal thermal power station, and the output of No. 6 unit is also slower during the work period of the solar heat power station with the amplitude of change is reduced.The phenomenon indicates which after the indraught of the CSP power station, mean yield of the thermal power unit lessens and the amplitude decreases, which indicates that the CSP power station can relieve the stress of the conventional power unit participating in peak shaving to a certain extent.It can be concluded from figure 7 that, since the intervention of solar thermal power plant (CSP), this details of wind turbine curtailment at dawn and night wind speed periods are improved, the curtailment  To sum up, based on the study of Table 1 and Figures 5, 6 and 7, after leading-in CSP energy plant, the total cost of the method and the reduction of air volume have been reduced, as well as the evenness power generation of thermal power sets has also decreased, reduce the scheduling pressure of traditional generator sets..The electromagnetic hotting equipment (EH) in the photothermal powerhouse heats the remaining wind power output, converts it into thermal properties and stores it in a hot backup system with a secure dispatching capacity, thus reducing the number of curtailments, increasing consumption of wind power.

Conclusion
This paper takes advantage of thermal storage system (TES) for solar thermal power plants, which can be used as energy storage equipment in principle, explores the economic problems the level of alternative energy absorption under different circumstances, and establishes a combined CSP-PV-Wind power generation system.Through the simulation system verification comparison of the IEEE-30 node, the whole operating cost of the system is reduced by 54.8%, and the curtailment air volume of the system is also reduced from the initial 3.23014 megawatts to 0.7313 MW, which improves consumptive level.So the research of this paper and the application of solar thermal power plants can promote effective implementation of the dual carbon goal development.

Figure 1 .
Figure 1.Composition of CSP-photovoltaic-wind power hybrid power generation system.

,max i PR
are the minimum and maximum output power of the thermal power unit; , show the ceiling amount down ascending velocity and up climbing velocity of the thermal power unit.

Figure. 4
Figure.4 explains the solar radiation intensity, PV forecast output and wind power output forecast in this area.The intensity of sunlight directly influences the output of solar thermal produce electricity and photovoltaic generate electricity.This figure also reflects from the side that CSP electricity generation and PV power generation have natural complementarity, et CSP power generation and wind generation are complementary advantages in time.

Figure 5 .
Figure 5.The output of thermal power stations without CSP.

Figure 6 .
Figure 6.The output of thermal power stations with CSP.
.1088/1742-6596/2728/1/012023 7 volume in other periods is also reduced to 0, the total reduction decreased from the initial 3.23014 MW to 0.73182 MW.

Table 1 .
Joint System Output Conditions.