Method and device for optimizing combined operation of hydropower and pumped storage power station

Abstract

The invention discloses a combined operation optimization method and device comprising a hydropower station and a pumped storage power station. The method comprises the following steps: constructing a combined operation system comprising a reversible hydropower station, a cascade hydropower station, the pumped storage power station, a wind power plant, a photovoltaic power station and a load; constructing a cascade hydropower station water flow model, a reversible hydropower station water flow model, a water flow and water flow time delay relation model and a water flow and generated output relation model; the operation optimization model of the combined operation system is constructed by taking the minimum comprehensive cost including the power generation cost, the start-stop cost and the wind and light abandoning cost as the target and taking the power balance constraint, the reversible hydropower station constraint, the cascade hydropower station constraint and the pumped storage power station constraint as the constraint conditions. And solving the operation optimization model of the joint operation system to obtain an optimal operation scheme. The overall power generation capacity of the combined operation system can be improved, the operation flexibility of the system can be improved while peak clipping and valley filling are achieved, and the wind abandoning amount, the light abandoning amount and the water abandoning amount of the system are reduced.

Description

Technical Field

[0001] The present invention relates to the field of energy power system optimization and dispatching, and in particular to a combined operation optimization method and device including hydropower and pumped storage power stations. Background Art

[0002] In the context of building a power system dominated by renewable energy, renewable energy represented by wind power and photovoltaic power will be connected to the power system on a large scale to achieve clean power production and consumption. The access of a high proportion of renewable energy has brought uncertainty and vulnerability to the system. The strong volatility and uncertainty of wind power generation and photovoltaic power generation have greatly increased the operation and maintenance costs of the power system to maintain instantaneous balance, and the peak period of user electricity consumption is often inconsistent and incompletely matched with the peak period of renewable energy generation in terms of time scale and spatial dimension. As a traditional peak-shaving and backup power source, hydropower has regained the attention of countries around the world. Pumped storage and conventional hydropower units with regulation performance play an irreplaceable role in all aspects of the source, grid, load and storage of the new power system. By adding pumped storage units and pump turbines, conventional hydropower stations can be equipped with the ability of pumped storage regulation to achieve the purpose of peak shaving and valley filling. Based on the reversible transformation of existing hydropower stations, its development cost is much lower than that of directly building new pumped storage power stations, and the transformation potential is huge. However, at the current stage, there is still a gap in the research on the joint operation mode of hydropower. How to reduce the fluctuation amplitude of the net load output curve through the coordinated and complementary operation of "source, grid, load and storage" to ensure the stable operation of the power system; how to achieve "time shift" of electricity to promote the grid connection of new energy and the recycling of water energy, and extend the continuous operation time of pumped storage and hydropower stations. There is currently a lack of in-depth and systematic research on these issues. Therefore, it is particularly necessary to study the flexible operation technology of pumped storage at multiple time and space scales under the coordination of source, grid, load and storage.

[0003] In recent years, many scholars have conducted relevant research on the operation and development of hydropower stations. Existing literature points out that the hydropower development model has gradually changed from the early large-scale cascade development to the direction of inter-basin water diversion, transformation of old (small) hydropower stations and pumped storage power stations; existing literature proposes a comprehensive energy system that includes new energy and small pumped storage; existing literature introduces pumped storage in conventional hydropower plants, using the abandoned new energy to power the pumping station and pump water from the adjacent downstream reservoir; the results of the above literature all show that the coordinated operation of conventional hydropower stations and pumped storage can make up for the randomness and unevenness of new energy such as wind energy and photovoltaic energy in the power grid, improve the power generation structure and reduce revenue losses. How to coordinate the operation of pumped storage units and conventional hydropower under the premise of meeting the tasks of peak load regulation and valley filling of the power grid and improve the common benefits is the main problem that needs to be solved in the current dispatching, including peak load regulation benefit model, output allocation of pumped storage units and conventional hydropower units, etc.; at the same time, the operation plan involves the upstream and downstream reservoirs of the cascade hydropower station group, and the pumping flow is closely related to the pumping time and the head difference between the upper and lower reservoirs, and its flow determination is a dynamic change process. In the above-mentioned research on the joint operation of pumped storage power stations and hydropower, the main consideration is to combine new energy to achieve clean production of electricity, but issues such as the coupled operation mode between pumped storage units and conventional hydropower units need further study.

[0004] Current research shows that the joint operation of pumped storage with thermal power, new energy and other power generation entities can jointly improve the benefits of both parties; hydropower has extremely strong coupling characteristics with pumped storage in terms of operating conditions and output characteristics. The coupled operation between the two can synergize and complement each other to achieve efficient utilization of water resources. The joint operation of pumped storage power stations and hydropower is a key step in the construction of new power systems. Existing literature points out that the addition of pumped storage units has enhanced the complementary space between water, wind and light in the basin, and optimized the power output and improved the grid's ability to absorb intermittent renewable energy by utilizing the high-quality regulation capacity of hydropower and the advantages of load regulation, frequency regulation and standby of pumped storage; existing literature proposes a complementary power generation system tracking and scheduling plan strategy based on coordinated control of cascade hydropower and pumped storage, and the output power of cascade hydropower and pumped storage is coordinated and allocated in the scheduling plan; existing literature aims to minimize scheduling costs and establishes a day-ahead-real-time double-layer model of cascade hydro-photovoltaic storage power generation system, which can improve the system's power generation income while ensuring photovoltaic absorption; and some scholars have conducted research on the planning association model of hydropower and pumped storage, coordinated optimization control technology, and power sharing mode. The above research has laid a good foundation for the research content of this invention, and also provided reference value for the flexible operation mode of hydropower and pumped storage. At present, scholars have made certain achievements in the study of the operating characteristics and modes of pumped storage power stations, and have carried out analysis on the coupling mode of pumped storage and hydropower, but there is relatively little research on how to couple the operating modes of pumped storage and hydropower to achieve coordinated complementarity between source, grid, load and storage. Therefore, it is urgent to analyze the operating characteristics of pumped storage and hydropower, and explore the space for improving the flexible operation of the coupling between the two, so as to achieve the coordinated, complementary and flexible operation of pumped storage and hydropower. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects and problems existing in the prior art, and to provide a joint optimization method and device including hydropower and pumped storage power stations, which can not only improve the overall power generation capacity of the joint operation system, but also achieve peak shaving and valley filling while also improving the operating flexibility of the joint operation system and reducing the amount of wind, solar and water abandonment in the system.

[0006] To achieve the above objectives, the technical solution of the present invention is: a combined operation optimization method of a hydropower and pumped storage power station, comprising:

[0007] Construct a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads;

[0008] Construct water flow models for cascade hydropower stations, water flow models for reversible hydropower stations, models for the relationship between water flow and water flow time lag, and models for the relationship between water flow and power generation output;

[0009] With the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and energy abandonment cost, and with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped-storage power station constraints as constraints, an operation optimization model of the joint operation system is constructed, and the operation optimization model of the joint operation system is solved to obtain the optimal operation plan.

[0010] The water flow model of the cascade hydropower station includes a water flow relationship model of the upstream cascade hydropower station and a water flow relationship model of the downstream cascade hydropower station;

[0011] The water flow relationship model of the upstream cascade hydropower station is:

[0012] Q s-1，t =Q s-，t-1 +N s-1,t -G s-1,t -W s-1，t ;

[0013] In the formula, Q s-1，t , Q s-1，t-1 are the storage capacities of the upstream cascade hydropower station s-1 at time t and t-1 respectively; N s-1,t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t;

[0014] The water flow relationship model of the downstream cascade hydropower station is:

[0015]

[0016] In the formula, Q s,t , Q s,t-1 is the storage capacity of the downstream cascade hydropower station S at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station s at time t; τ h is the hysteresis time of water flow; is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the power generation and discharge flow of the downstream cascade hydropower station s at time t; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station s at time t.

[0017] The reversible hydropower station water flow model includes an upstream cascade hydropower station water flow relationship model and a downstream cascade hydropower station water flow relationship model;

[0018] The water flow relationship model of the upstream cascade hydropower station is:

[0019]

[0020] In the formula, is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station s-1 at time t; Q s-1，t , Q s-1，t N -1 is the storage capacity of the upstream cascade hydropower station s-1 at time t and t-1 respectively; s-1，t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t;

[0021] The water flow relationship model of the downstream cascade hydropower station is:

[0022]

[0023] In the formula, Q s，t , Q s，t-1 is the storage capacity of the downstream cascade hydropower station s at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station s at time t; τ h is the hysteresis time of water flow; is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the power generation and discharge flow of the downstream cascade hydropower station s at time t; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station s at time t; It is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station s-1 at time t.

[0024] The water flow and water flow time lag relationship model is:

[0025]

[0026] In the formula, τ h is the hysteresis time of water flow; d 0 d 1 d 2 is the conversion factor; is the outflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the discharge flow of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t.

[0027] The water flow and power generation output relationship model includes a water-to-electricity conversion relationship model and a water head-storage capacity relationship model;

[0028] The hydropower conversion relationship model is:

[0029] P = 9.81ρηqh;

[0030] In the formula, P is the power output of the hydropower station; ρ is the density of water; η is the conversion efficiency of water energy to electrical energy; q is the power flow; h is the water head height;

[0031] The head-storage capacity relationship model is:

[0032] h=f 0 +f 1 ·V+f 2 ·V 2 +…+f n ·V n ;

[0033] Where V is the reservoir capacity of the hydropower station; f 0 、f 1 、f 2 、f n are the polynomial coefficients.

[0034] The objective function of the joint operation system operation optimization model is:

[0035] F cost =min(f 1 +f 2 +f 3 );

[0036]

[0037] In the formula, F cost is the comprehensive cost of the joint operation system; 1 、f 2 and f 3 They are the power generation cost, start-up and shutdown cost, and energy abandonment cost of the combined operation system; is the electricity price at time t; is the pumping state variable of the pumped storage power station at time t; is the pumping power of the pumped storage power station at time t; is the pumping state variable of the reversible hydropower station at time t; is the pumping power of the reversible hydropower station at time t; c on The start-up costs of pumped storage power plants; is the power generation state variable of the pumped storage power station at time t; c offShutdown costs for pumped storage power plants; is the power generation state variable of the reversible hydropower station at time t; c cur is the energy abandonment cost coefficient; is the wind power abandoned at time t; is the amount of abandoned light in the photovoltaic power station at time t; is the amount of water abandoned by the hydropower station at time t.

[0038] The power balance constraint is:

[0039]

[0040] Where P W，t and P PV，t are the power generation of the wind farm and photovoltaic power station at time t respectively; and P CH，t are the power generation capacities of pumped storage power station, reversible hydropower station and cascade hydropower station at time t respectively; and are the pumping power of the pumped storage power station and the reversible hydropower station respectively; L t is the load value at time t;

[0041] The pumped storage power station constraints include output constraints, state constraints and storage capacity constraints;

[0042] The output constraints are:

[0043]

[0044] In the formula, are the lower and upper limits of the power generation of the pumped storage power station at time t respectively; are the lower and upper limits of the pumping power of the pumped storage power station at time t respectively; and are the generating power and pumping power of the pumped storage power station at time t respectively; and are the power generation state variable and pumping state variable of the pumped storage power station at time t respectively;

[0045] The state constraints are:

[0046]

[0047] The inventory capacity constraint is:

[0048]

[0049]

[0050] In the formula, and are the real-time capacity, upper and lower limits of the pumped storage power station respectively; η C and η D are the power generation efficiency and pumping efficiency of the pumped storage power station respectively; and They are the initial storage capacity and final storage capacity of the pumped storage power station respectively; are the storage capacities of the pumped-storage power station at time t-1 and time t respectively.

[0051] A combined operation optimization device for a hydropower and pumped storage power station, which is applied to the above-mentioned method, comprises:

[0052] Joint operation system building module, used to build a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads;

[0053] Model building module, used to build the water flow model of cascade hydropower stations, the water flow model of reversible hydropower stations, the relationship model between water flow and water flow time lag, and the relationship model between water flow and power generation output;

[0054] The optimal operation plan solving module is used to build an operation optimization model of the joint operation system with the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and energy abandonment cost, and to solve the operation optimization model of the joint operation system to obtain the optimal operation plan with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped storage power station constraints as constraints.

[0055] A device for optimizing the combined operation of a hydropower and pumped storage power plant, including a memory and a processor;

[0056] The memory is used to store computer program code and transmit the computer program code to the processor;

[0057] The processor is used to execute the method according to the instructions in the computer program code.

[0058] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] In the joint operation optimization method and device of the present invention including hydropower and pumped storage power station, the proposed joint operation optimization mode can play an important role in the four sides of source, network, load and storage. Pumped storage power station, reversible hydropower station and cascade hydropower station can generate electricity and have the characteristics of power supply side; pumped storage power station and reversible hydropower station can provide auxiliary services such as peak regulation, frequency regulation and standby, and can play a role in ensuring the safety and stability of the system on the power grid side; pumped storage power station and reversible hydropower station have pumping mode, which can both play the role of load, thereby increasing the load level in the valley period and reducing the peak-to-valley difference of the system load; in addition, pumped storage power station and reversible hydropower station are also the main bodies of the energy storage side, and the new energy electricity is converted into water potential energy through the pump turbine and stored in the reservoir, and then converted into electric energy and output to the system during the peak load period. Therefore, the present invention can not only improve the overall power generation capacity of the joint operation system, but also improve the operation flexibility of the joint operation system while realizing peak shaving and valley filling, and reduce the wind abandonment, solar abandonment and water abandonment of the joint operation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a flow chart of a combined operation optimization method including hydropower and pumped storage power stations of the present invention.

[0062] Figure 2 It is the joint operation system framework mentioned in the embodiments of the present invention.

[0063] Figure 3 It is a schematic diagram of the relationship of water flow in the cascade hydropower station mentioned in the embodiment of the present invention.

[0064] Figure 4 It is a schematic diagram of the water flow relationship of the reversible hydropower station mentioned in the embodiment of the present invention.

[0065] Figure 5 It is a structural block diagram of a combined operation optimization device including a hydropower and pumped storage power station according to the present invention.

[0066] Figure 6 It is a structural block diagram of a joint operation optimization device including a hydropower and pumped storage power station according to the present invention. DETAILED DESCRIPTION

[0067] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0068] See also Figure 1 , a combined operation optimization method for a hydropower and pumped storage power station, comprising:

[0069] S1. Construct a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads.

[0070] The present invention equips a reversible hydropower station and a cascade hydropower station near a pumped storage power station. The reversible hydropower station, cascade hydropower and pumped storage power station are operated in a joint framework as follows: Figure 2 As shown. The joint operation system mainly includes wind farms, photovoltaic power stations, cascade hydropower stations, reversible hydropower stations, pumped storage power stations and loads. Among them, wind farms, photovoltaic power stations, cascade hydropower stations and reversible hydropower stations are the main energy equipment to ensure the power supply load demand. Pumped storage power stations have the advantages of fast start-up, flexible operation, and rapid conversion of power generation and pumping conditions. They can achieve rapid power regulation, energy transfer, peak shaving and valley filling. The combination of reversible hydropower stations, cascade hydropower and pumped storage power stations can improve the overall power generation capacity and maintain the power balance of the system.

[0071] S2. Construct a water flow model for cascade hydropower stations, a water flow model for a reversible hydropower station, a model for the relationship between water flow and water flow time lag, and a model for the relationship between water flow and power generation output.

[0072] S3. With the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and energy abandonment cost, and with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped storage power station constraints as constraints, a joint operation system operation optimization model is constructed, and the joint operation system operation optimization model is solved to obtain the optimal operation plan.

[0073] When the joint operation system runs the optimization model, the nonlinear terms in the model are converted into linear terms through the piecewise linear approximation method, and the CPLEX mathematical solver is called in MATLAB to solve the mixed integer linear programming model.

[0074] The advantages of the joint operation system are mainly reflected in the following aspects: (1) In the joint operation mode, when the power supply to the grid is limited, wind farms, photovoltaic power stations and cascade hydropower stations can use the abandoned wind, abandoned solar and abandoned water to supply the generated electricity to pumped storage power stations or reversible hydropower stations, thereby pumping water from the lower reservoir to the upper reservoir, increasing the power generation capacity of the pumped storage power station and the reversible hydropower station. In this process, the hydropower station improves the utilization efficiency of water resources and enhances the overall power generation capacity of the joint operation system by raising the water level of the upper reservoir. (2) During the power off-peak period, the joint operation system can use the reversible hydropower station and the pumped storage power station to operate in pumping conditions, convert the excess electric energy in the power system into the potential energy of water and store it in the upper reservoir, and then generate electricity during the peak power demand period for peak-valley arbitrage, thereby achieving peak shaving and valley filling, and improving the system's operating flexibility and reducing the amount of wind, solar and abandoned water in the system.

[0075] Furthermore, there are close hydraulic and electrical connections between the cascade power stations. The power generation efficiency of hydropower stations at all levels is greatly affected by the upstream and downstream hydropower stations. The water inflow of the downstream hydropower station is directly restricted by the upstream hydropower station. At the same time, the return water of the downstream hydropower station may also cause the water head to the upstream power station. If the cascade hydropower stations are operated separately, it is easy to cause an increase in the water consumption rate of power generation and useless water abandonment in the reservoir, resulting in a decrease in the overall water energy utilization rate of the cascade. The implementation of joint operation of cascade hydropower station groups is based on the perspective of maximizing the overall water energy utilization rate of the river basin. It can not only give full play to the regulation performance of the leading reservoir, but also utilize the non-synchronous inflow of each hydropower plant and the different regulation capabilities of the reservoir. The cascade reservoirs can reasonably determine the water storage and supply order of the cascade reservoirs through storage capacity compensation regulation, runoff compensation regulation, and power compensation regulation, improve the guaranteed output and guaranteed electricity of the cascade hydropower station group, increase the working reliability of the hydropower station group, and increase the necessary capacity and installed capacity of the hydropower station, reduce water abandonment, and make full use of the flow, head and storage capacity of each power station, improve the comprehensive utilization efficiency of river water resources, thereby realizing the optimized economic operation of the cascade hydropower station group in the basin and creating more social and economic benefits.

[0076] The relationship between water flow of cascade hydropower stations is as follows Figure 3 As shown in the figure, it can be seen that the water flow of the upstream cascade power station in the basin comes from natural water, which is greatly affected by natural conditions such as environment, climate, and season; while the water flow of the downstream cascade power station is composed of the regional water flow between the two cascade power stations and the upstream discharge. Moreover, the upstream discharge is generally the main source of water flow for the downstream cascade power station. Therefore, the water storage and power generation of the downstream cascade hydropower station are greatly affected by the upstream cascade power station, and there is a close hydraulic coupling relationship between the two.

[0077] The water flow model of the cascade hydropower station includes a water flow relationship model of the upstream cascade hydropower station and a water flow relationship model of the downstream cascade hydropower station;

[0078] The water flow relationship model of the upstream cascade hydropower station is:

[0079] Q s-1，t =Q s-1，t-1 +N s-1，t G s-1，t -W s-1，t ;

[0080] In the formula, Q s-1，t , Q s-1，t-1 are the storage capacities of the upstream cascade hydropower station s-1 at time t and t-1 respectively; N s-1，t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，tis the amount of water abandoned by the upstream cascade hydropower station s-1 at time t;

[0081] The water flow relationship model of the downstream cascade hydropower station is:

[0082]

[0083] In the formula, Q s，t , Q s,t-1 is the storage capacity of the downstream cascade hydropower station S at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station s at time t; τ h It is the hysteresis time of water flow. The reason is that there is a certain distance between the upstream and downstream of the cascade hydropower station. Due to the insufficient water flow speed, part of the water volume did not reach the reservoir of the downstream power station during this period. is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the power generation and discharge flow of the downstream cascade hydropower station s at time t; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station s at time t.

[0084] Furthermore, unlike conventional cascade hydropower stations, reversible hydropower stations can use reversible water pumps to pump water from the downstream to the upper reservoir, changing the direction of water flow. Therefore, the water flow relationship of the reversible hydropower station changes. Based on the above conventional cascade hydropower station water flow relationship, the water flow relationship inside the cascade hydropower station is further analyzed after the reversible water pump is connected. The water flow relationship of the reversible hydropower station is as follows: Figure 4 shown.

[0085] Since the reversible water pump can pump the downstream water to the upstream cascade hydropower station, the water flow of the upstream cascade hydropower station should include this part of the water, and the reversible hydropower station water flow model includes the upstream cascade hydropower station water flow relationship model and the downstream cascade hydropower station water flow relationship model;

[0086] The water flow relationship model of the upstream cascade hydropower station is:

[0087]

[0088] In the formula, is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station s-1 at time t; Q s-1，t , Q s-1，t-1 are the storage capacities of the upstream cascade hydropower station s-1 at time t and t-1 respectively; N s-1，t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，tis the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t;

[0089] The water flow relationship model of the downstream cascade hydropower station is:

[0090]

[0091] In the formula, Q s，t , Q s，t-1 is the storage capacity of the downstream cascade hydropower station s at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station s at time t; τ h It is the hysteresis time of water flow. The reason is that there is a certain distance between the upstream and downstream of the cascade hydropower station. Due to the insufficient water flow speed, part of the water volume did not reach the reservoir of the downstream power station during this period. is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the power generation and discharge flow of the downstream cascade hydropower station s at time t; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station s at time t; It is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station s-1 at time t.

[0092] Furthermore, when scheduling cascade hydropower, the length of the propagation time of water flow between cascade power stations has different effects on joint optimization. If the water flow time lag is less than the scheduling period, the effect on optimization is small and this factor can be ignored in the optimization process; if the water flow time lag is greater than the scheduling period and less than the scheduling period, the water flow time lag problem needs to be considered in the water balance equation of the cascade hydropower station; if the water flow time lag is greater than the scheduling period, the hydraulic connection during the scheduling period is weakened. Therefore, it is necessary to process the water flow time lag between cascade hydropower stations to accurately model cascade hydropower. At present, the methods for processing water flow time lag mainly include hydrology and hydraulics, both of which require detailed data as a basis, and the calculation is extremely complex and difficult to use in actual production. In engineering, conventional processing methods consider that the water flow time lag between hydropower stations is affected by many factors, and due to technical limitations, the water flow time lag is often used as a constant output, which is obtained from the historical average value. With the research of intelligent algorithms and the improvement of hardware conditions in recent years, the traditional water flow time lag processing methods can be optimized. Historical data show that the water flow time lag has a significant correlation with the outflow of the upstream reservoir. The water flow time lag is modeled using a polynomial, and its mathematical form is as follows:

[0093]

[0094] In the formula, τ h is the hysteresis time of water flow; d 0 d 1 d 2 is the conversion coefficient, obtained by fitting the historical outflow-water flow time lag relationship curve; is the outflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the discharge flow of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t.

[0095] Furthermore, the water flow and power generation output relationship model includes a water-to-electricity conversion relationship model and a water head-storage capacity relationship model;

[0096] The hydropower conversion relationship model is:

[0097] P = 9.81ρηqh;

[0098] Where P is the power output of the hydropower station; ρ is the density of water, which is 1×10 3 kg / m 3 ; η is the conversion efficiency of water energy to electrical energy, which includes the turbine efficiency coefficient and the generator efficiency coefficient, and is obtained by fitting the historical power generation data; q is the power generation flow; h is the water head height;

[0099] The water head of a hydropower station will affect the power generation, and the water inflow and discharge of the reservoir will affect the water head, thereby affecting the power generation. In a hydropower station, the relationship between the water head and the reservoir capacity is often more complicated. The present invention uses a polynomial to fit it, that is, the water head-reservoir capacity relationship model is:

[0100] h=f 0 +f 1 ·V+f 2 ·V 2 +…+f n ·V n ;

[0101] Where V is the reservoir capacity of the hydropower station; f 0 、f 1 、f 2 、f n are the polynomial coefficients.

[0102] Furthermore, the objective function of the joint operation system operation optimization model is:

[0103] F cost =min(f 1 +f 2 +f 3 );

[0104]

[0105] In the formula, F cost is the comprehensive cost of the joint operation system; 1 、f 2 and f 3 They are the power generation cost, start-up and shutdown cost, and energy abandonment cost of the combined operation system; is the electricity price at time t; is the pumping state variable of the pumped storage power station at time t, 1 indicates pumping, and 0 indicates other states; is the pumping power of the pumped storage power station at time t; is the pumping state variable of the reversible hydropower station at time t, 1 indicates pumping, and 0 indicates other states; is the pumping power of the reversible hydropower station at time t; c on The start-up costs of pumped storage power plants; is the power generation state variable of the pumped storage power station at time t, 1 indicates power generation, and 0 indicates other states; c off Shutdown costs for pumped storage power plants; is the power generation state variable of the reversible hydropower station at time t, 1 indicates power generation, and 0 indicates other states; c cur is the energy abandonment cost coefficient; is the wind power abandoned at time t; is the amount of abandoned light in the photovoltaic power station at time t; is the amount of water abandoned by the hydropower station at time t.

[0106] Furthermore, the power balance constraint is:

[0107]

[0108] Where P W，t and P PV，t are the power generation of the wind farm and photovoltaic power station at time t respectively; and P CH，t are the power generation capacities of pumped storage power station, reversible hydropower station and cascade hydropower station at time t respectively; and are the pumping power of the pumped storage power station and the reversible hydropower station respectively; L t is the load value at time t.

[0109] The constraints of reversible hydropower stations include water flow balance constraints, outflow constraints, reservoir capacity constraints and hydropower station output constraints;

[0110] The water flow balance constraint is:

[0111]

[0112] The outbound flow constraints are:

[0113]

[0114] In the formula, They are the upper and lower limits of the pumping flow rate of a reversible hydropower station, respectively; are the upper and lower limits of the power generation flow of the reversible hydropower station respectively; q pw ,q ge are the pumping flow and power generation flow of the reversible hydropower station respectively;

[0115] The storage capacity constraint is:

[0116] V s-1,min ≤V s-1，t ≤V s-1,max ;

[0117] V s,min ≤V s,t ≤V s,max ;

[0118] Where V s-1，max 、V s-1，min are the upper and lower limits of the reservoir capacity of the upstream cascade hydropower station s-1; V s，max 、V s，min are the upper and lower limits of the reservoir capacity of the downstream cascade hydropower station s; V s-1，t 、V s，t are the storage capacities of the upstream cascade hydropower station s-1 and the downstream cascade hydropower station S at time t respectively;

[0119] The output constraints of the hydropower station are:

[0120] P s,min ≤P s，t ≤P s，max ;

[0121] P s-1,min ≤P s-1，t ≤P s-1,max ;

[0122] Where P s-1，max , P s-1，min are the upper and lower limits of the output of the upstream cascade hydropower station s-1; P s，max , P s，min are the upper and lower limits of the output of the downstream cascade hydropower station s, respectively. The maximum output is generally the installed capacity or expected output; P s-1，t , P s，t are the outputs of the upstream cascade hydropower station s-1 and the downstream cascade hydropower station s at time t respectively;

[0123] The constraints of cascade hydropower stations include water flow balance constraints, outflow constraints, reservoir capacity constraints and hydropower station output constraints;

[0124] The water flow balance constraint is:

[0125] Q s-1，t =Q s-1，t-1 +N s-1，t -G s-1，t -W s-1，t ;

[0126]

[0127] The outbound flow constraints are:

[0128] q min ≤q≤q max ;

[0129] In the formula, q min ,q max They are the minimum and maximum discharge capacities of cascade hydropower stations respectively.

[0130] The reservoir capacity constraint and the hydropower station output constraint are the same as those in the reversible hydropower station constraint.

[0131] Pumped storage power station constraints include output constraints, state constraints, and storage capacity constraints;

[0132] The output of a pumped storage power station should not exceed the power output limit in each period, so the output constraint is:

[0133]

[0134] In the formula, are the lower and upper limits of the power generation of the pumped storage power station at time t respectively; are the lower and upper limits of the pumping power of the pumped storage power station at time t respectively; and are the generating power and pumping power of the pumped storage power station at time t respectively; and are the power generation state variable and pumping state variable of the pumped storage power station at time t, 1 indicates power generation / pumping, and 0 indicates other states;

[0135] A pumped storage power station can only operate in power generation or pumping mode at the same time, so the state constraint is:

[0136]

[0137] The actual operating output of a pumped storage power station is also constrained by storage capacity:

[0138]

[0139] In the formula, and are the real-time capacity, upper and lower limits of the pumped storage power station respectively; η C and η D are the power generation efficiency and pumping efficiency of the pumped storage power station respectively; and They are the initial storage capacity and final storage capacity of the pumped storage power station respectively; are the storage capacities of the pumped-storage power station at time t-1 and time t respectively.

[0140] See also Figure 5 The present invention also provides a combined operation optimization device including hydropower and pumped storage power stations, which is applied to the combined operation optimization method including hydropower and pumped storage power stations described above, and the device comprises:

[0141] Joint operation system building module, used to build a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads;

[0142] Model building module, used to build the water flow model of cascade hydropower stations, the water flow model of reversible hydropower stations, the relationship model between water flow and water flow time lag, and the relationship model between water flow and power generation output;

[0143] The optimal operation plan solving module is used to build an operation optimization model of the joint operation system with the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and wind and solar power abandonment cost, and to solve the operation optimization model of the joint operation system to obtain the optimal operation plan with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped storage power station constraints as constraints.

[0144] See also Figure 6 , the present invention also provides a combined operation optimization device including a hydropower and pumped storage power station, including a memory and a processor;

[0145] The memory is used to store computer program code and transmit the computer program code to the processor;

[0146] The processor is used to execute the above-mentioned combined operation optimization method involving hydropower and pumped storage power stations according to the instructions in the computer program code.

[0147] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the above-mentioned method for optimizing the combined operation of a hydropower and pumped-storage power station is implemented.

[0148] Generally speaking, the computer instructions for implementing the method of the present invention may be carried in any combination of one or more computer-readable storage media. Non-transitory computer-readable storage media may include any computer-readable media, except for the signal itself that is temporarily propagating.

[0149] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EKROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0150] Computer program code for performing the operation of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages, in particular, Python suitable for neural network computing and platform frameworks based on TensorFlow, PyTorch, etc. can be used. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer or to an external computer (for example, using an Internet service provider to connect via the Internet) through any type of network, including a local area network (LAN) or a wide area network (WAN).

[0151] The above-mentioned device and non-temporary computer-readable storage medium can be found in the specific description of a combined operation optimization method including hydropower and pumped storage power stations and its beneficial effects, which will not be repeated here.

[0152] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for optimizing the combined operation of a hydropower and pumped storage power station, characterized in that: include: Construct a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads; Construct water flow models for cascade hydropower stations, water flow models for reversible hydropower stations, models for the relationship between water flow and water flow time lag, and models for the relationship between water flow and power generation output; With the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and energy abandonment cost, and with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped-storage power station constraints as constraints, an operation optimization model of the joint operation system is constructed, and the operation optimization model of the joint operation system is solved to obtain the optimal operation plan.

2. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The water flow model of the cascade hydropower station includes a water flow relationship model of the upstream cascade hydropower station and a water flow relationship model of the downstream cascade hydropower station; The water flow relationship model of the upstream cascade hydropower station is: Q s-1，t =Q s-1，t-1 +N s-1，t -G s-1，t -W s-1，t ; In the formula, Q s-1，t , Q s-1，t-1 are the storage capacities of the upstream cascade hydropower station s-1 at time t and t-1 respectively; N s-1，t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t; The water flow relationship model of the downstream cascade hydropower station is: In the formula, Q s，t Q s，t-1 is the storage capacity of the downstream cascade hydropower station S at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station S at time t; τ h is the hysteresis time of water flow; is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the power generation and discharge flow of the downstream cascade hydropower station s at time t; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station s at time t.

3. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The reversible hydropower station water flow model includes an upstream cascade hydropower station water flow relationship model and a downstream cascade hydropower station water flow relationship model; The water flow relationship model of the upstream cascade hydropower station is: In the formula, is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station s-1 at time t; Q s-1，t , Q s-1，t-1 are the storage capacities of the upstream cascade hydropower station s-1 at time t and t-1 respectively; N s-1，t is the natural water inflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the water discharge of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t; The water flow relationship model of the downstream cascade hydropower station is: In the formula, Q s，t , Q s，t-1 is the storage capacity of the downstream cascade hydropower station s at time t and t-1; N s，t is the natural water inflow of the downstream cascade hydropower station S at time t; τ h is the hysteresis time of water flow; is the upstream cascade hydropower station s-1 at t-τ h The power discharge flow at the moment; G s，t is the discharge flow of the downstream cascade hydropower station s at time ; is the upstream cascade hydropower station s-1 at t-τ h The amount of water discarded at the time; W s，t is the amount of water abandoned by the downstream cascade hydropower station S at time t; It is the water flow rate pumped by the reversible water pump to the upstream cascade hydropower station S-1 at time t.

4. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The water flow and water flow time lag relationship model is: In the formula, τ h is the hysteresis time of water flow; d0, d1, d2 are conversion coefficients; is the outflow of the upstream cascade hydropower station s-1 at time t; G s-1，t is the discharge flow of the upstream cascade hydropower station s-1 at time t; W s-1，t is the amount of water abandoned by the upstream cascade hydropower station s-1 at time t.

5. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The water flow and power generation output relationship model includes a water-to-electricity conversion relationship model and a water head-storage capacity relationship model; The hydropower conversion relationship model is: P = 9.81ρηqh; In the formula, P is the power output of the hydropower station; ρ is the density of water; η is the conversion efficiency of water energy to electrical energy; q is the power flow; h is the water head height; The head-storage capacity relationship model is: h=f0+f1·V+f2·V 2 +…+f n ·In n ; Where V is the reservoir capacity of the hydropower station; f0, f1, f2, f n are the polynomial coefficients.

6. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The objective function of the joint operation system operation optimization model is: <h2 style=";text-align:left;direction:ltr">F<h2 style=";text-align:left;direction:ltr"> cost <h2 style=";text-align:left;direction:ltr"> (min(f1+f2+f3)) In the formula, F cost is the comprehensive cost of the joint operation system; f1, f2 and f3 are the power generation cost, start-up and shutdown cost, and energy abandonment cost of the joint operation system respectively; is the electricity price at the time; is the pumping state variable of the pumped storage power station at time t; is the pumping power of the pumped storage power station at time t; is the pumping state variable of the reversible hydropower station at time t; is the pumping power of the reversible hydropower station at time t; c on The start-up costs of pumped storage power plants; is the power generation state variable of the pumped storage power station at time t; c off Shutdown costs for pumped storage power plants; is the power generation state variable of the reversible hydropower station at time t; c cur is the energy abandonment cost coefficient; is the wind power abandoned at time t; is the amount of abandoned light in the photovoltaic power station at time t; is the amount of water abandoned by the hydropower station at time t.

7. A combined operation optimization method for a hydropower and pumped storage power station according to claim 1, characterized in that: The power balance constraint is: Where P W，t and P PV，t are the power generation of the wind farm and photovoltaic power station at time t respectively; and P CH，t are the power generation capacities of pumped storage power station, reversible hydropower station and cascade hydropower station at time t respectively; and are the pumping power of the pumped storage power station and the reversible hydropower station respectively; L t is the load value at time t; The pumped storage power station constraints include output constraints, state constraints and storage capacity constraints; The output constraints are: In the formula, are the lower and upper limits of the power generation of the pumped storage power station at time t respectively; are the lower and upper limits of the pumping power of the pumped storage power station at time t; P t ge and P t pw are the generating power and pumping power of the pumped storage power station at time t respectively; and are the power generation state variable and pumping state variable of the pumped storage power station at time t respectively; The state constraints are: The inventory capacity constraint is: In the formula, and are the real-time capacity, upper and lower limits of the pumped storage power station respectively; η C and η D are the power generation efficiency and pumping efficiency of the pumped storage power station respectively; and They are the initial storage capacity and final storage capacity of the pumped storage power station respectively; are the storage capacities of the pumped-storage power station at time t-1 and time t respectively.

8. A combined operation optimization device for a hydropower and pumped storage power station, characterized in that: The device is applied to the method described in any one of claims 1 to 7, and the device comprises: Joint operation system building module, used to build a joint operation system including reversible hydropower stations, cascade hydropower stations, pumped storage power stations, wind farms, photovoltaic power stations and loads; Model building module, used to build the water flow model of cascade hydropower stations, the water flow model of reversible hydropower stations, the relationship model between water flow and water flow time lag, and the relationship model between water flow and power generation output; The optimal operation plan solving module is used to build an operation optimization model of the joint operation system with the goal of minimizing the comprehensive cost including power generation cost, start-up and shutdown cost, and energy abandonment cost, and to solve the operation optimization model of the joint operation system to obtain the optimal operation plan with power balance constraints, reversible hydropower station constraints, cascade hydropower station constraints, and pumped storage power station constraints as constraints.

9. A combined operation optimization device comprising a hydropower and pumped storage power station, characterized in that: including memory and processor; The memory is used to store computer program code and transmit the computer program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 7 according to instructions in the computer program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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