Coordination control system and method for gravity energy storage power station

Abstract

The invention discloses a coordination control system and method for a gravity energy storage power station, and the system comprises a data collection module which is used for collecting the parameters of a grid connection point of the gravity energy storage power station in real time; the calculation module is used for calculating a system regulation power grid frequency value according to the collected data, determining the number of grid-connected / off-grid gravity energy storage units, generating a corresponding energy storage or release instruction, and issuing a total output / input power value of the gravity energy storage system; the instruction generation and distribution module is used for generating a power increase and decrease instruction for each converter according to the output of the calculation module; the converter cooperation module is used for enabling each converter to adjust the output power according to the instruction after receiving the instruction; and the state monitoring and feedback module is used for monitoring the overall operation state of the gravity energy storage power station and the performance index of the power grid auxiliary service in real time so as to realize the dynamic optimization of the system. According to the scheme, the overall response consistency of the gravity energy storage power station is improved, and the time delay requirement of power grid auxiliary service can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of gravity energy storage, and in particular relates to a coordinated control system and method for a gravity energy storage power station. Background Art

[0002] Gravity energy storage is to form a heavy flow of discrete heavy objects to generate electricity continuously. The transportation efficiency of gravity energy storage elements per unit time is low and the power configuration is limited, which limits its energy storage capacity and makes it impossible to achieve large-scale and efficient energy storage. Therefore, multiple gravity energy storage modules need to be centralized and coordinated. In scenarios where a large number of gravity energy storage modules participate in grid auxiliary services, how to achieve fast and accurate synchronous control becomes a technical challenge. Traditional control methods are difficult to meet the time delay requirements of hundreds of milliseconds, resulting in inconsistent overall responses of energy storage modules and affecting the stable operation of the power grid. Therefore, an efficient coordinated control system is urgently needed to solve this problem. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a coordinated control system and method for a gravity energy storage power station, so as to solve the problem that the existing solutions are difficult to meet the time delay requirements of hundreds of milliseconds, realize fast and accurate synchronous control, and achieve consistency of the overall response of the gravity energy storage power station.

[0004] According to the technical solution of the present invention, the present invention provides a coordinated control system for a gravity energy storage power station, comprising:

[0005] Data acquisition module, which is used to collect parameters such as voltage and frequency of the grid connection point of the gravity energy storage power station in real time;

[0006] A calculation module is used to calculate the grid frequency value adjusted by the system according to the collected data, determine the number of grid-connected / off-grid gravity energy storage units, generate corresponding energy storage or release instructions, and issue the total output / input power value of the gravity energy storage system;

[0007] An instruction generation and distribution module, which is used to generate power increase and decrease instructions for each converter according to the output of the calculation module, and send the instructions to the converter cooperation module through a high-speed communication network;

[0008] A converter cooperation module, which is used to enable each converter to adjust the output power according to the instruction after receiving the instruction;

[0009] The status monitoring and feedback module is used to monitor the overall operating status of the gravity energy storage power station and the performance indicators of the grid auxiliary services in real time, make adaptive adjustments based on the monitoring results, and feed back to the instruction generation and allocation module to achieve dynamic optimization of the system.

[0010] The present invention also provides a coordinated control method for a gravity energy storage power station, which adopts the coordinated control system for a gravity energy storage power station of the present invention, and comprises the following steps:

[0011] Step S1, collecting parameters of the grid connection point of the gravity energy storage power station in real time through a data acquisition module;

[0012] Step S2, the calculation module calculates the required adjustment frequency of the power grid according to the objective function;

[0013] Step S3, the instruction generation and allocation module determines the calculated required adjustment frequency of the power grid. When it is determined that the required adjustment frequency of the power grid is a positive number, the gravity energy storage system grid-connected unit is established, and the instruction generation and allocation module generates corresponding energy storage or energy release instructions according to the control strategy, sends them to the converter cooperation module, and continues to execute step S4; when it is determined that the required adjustment frequency of the power grid is a non-positive number, the number of grid-connected units of the gravity energy storage system is reduced, and the process returns to start from step S2;

[0014] Step S4, the converter cooperation module sends instructions to each converter, so that the converter adjusts its output power according to the received instructions, so as to realize cooperative work between the converters through the converter cooperation module;

[0015] Step S5: The status monitoring and feedback module monitors the operating status and performance indicators of the system in real time, and performs adaptive adjustment and optimization according to the monitoring results.

[0016] Furthermore, in step S2, the calculation module uses renewable energy fluctuation suppression and power demand of the power grid as the objective function:

[0017] Assume that the time when gravity energy storage participates in smoothing the fluctuation of renewable energy is [t1, t2]; in order to characterize the suppression effect of gravity energy storage on the fluctuation of renewable energy power generation, the optimization objective function f1 is established by minimizing the sum of squares of the difference of renewable energy power change after adjustment:

[0018]

[0019] In the formula, the subscript i represents the i-th period, P dg,i is the power generated by renewable energy, P G,i is the output power of the gravity energy storage system, P DG,i-1 is the output power value of renewable energy without gravity energy storage compensation, P DG,i is the output power value of renewable energy after gravity energy storage compensation;

[0020] Assume that gravity energy storage participates in the load balancing of the power grid throughout the whole process; Assume that the adjustment time is [t3, t4]; Based on the principle of minimizing the square of the instantaneous power deviation between supply and demand and the average deviation, establish the power demand matching objective function f2 of the power grid:

[0021]

[0022] Where P L,i is the load power, P avg is the average value of the difference between supply and demand after energy storage is applied;

[0023] In summary, the mathematical model of the minimum regulation frequency of the gravity energy storage grid-connected system is obtained by optimization:

[0024]

[0025] The difference between the output power of the gravity energy storage and the total output power reference value of the gravity energy storage device system and the required frequency adjustment value of the power grid are used as the control input of the gravity energy storage system. The control process is expressed as follows:

[0026] P f =P ref +K g f t ,

[0027] Where P f is the overall compensation output power of the gravity energy storage system, P ref is the total output power reference value of the system, K g is the unit adjustment power of the gravity energy storage device, f t Adjust the frequency value required by the power grid.

[0028] Furthermore, in step S3, the instruction generation and distribution module uses a proportional control algorithm to set a proportional coefficient according to the overall requirements of the system and the status of each converter, and then calculates the power that each converter should increase or decrease according to the proportional coefficient; the calculation formula is as follows:

[0029] ΔP_i=K(P f -P c ),

[0030] Where ΔP_i is the power that the i-th converter should increase or decrease, K is the proportional coefficient, and P f is the overall compensation output power of the gravity energy storage system, P c is the total power of all current converters.

[0031] Furthermore, step S4 further comprises:

[0032] The converter collaboration module exchanges information through the communication network, adjusts the instructions to each converter, and implements collaborative decision-making to meet the needs and stability of the overall system; the converter collaboration module sends instructions to each converter;

[0033] Each converter receives one or more instructions via the communication interface, and then according to the received instructions, the converter adjusts its output power and / or frequency;

[0034] In the process of adjusting the power output, the converter has a feedback mechanism to further optimize according to the actual operating results.

[0035] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0036] The coordinated control system and method for a gravity energy storage power station of the present invention are particularly suitable for participating in grid auxiliary services, such as transient control processes such as primary frequency regulation and dynamic voltage regulation. The system generates corresponding power increase and decrease instructions by measuring the parameters of the grid connection point of the gravity energy storage power station, and distributes and notifies them in all converters to achieve collaborative work between converters. The system significantly improves the overall response consistency of the gravity energy storage power station and can meet the latency requirements of grid auxiliary services. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention provides a coordinated control system and method for a gravity energy storage power station, which solves the problem that the existing solution is difficult to meet the delay requirement of 100 milliseconds, realizes fast and accurate synchronous control, and realizes the consistency of the overall response of the gravity energy storage power station. This solution is particularly suitable for participating in grid auxiliary services, such as transient control processes such as primary frequency regulation and dynamic voltage regulation.

[0039] A coordinated control system for a gravity energy storage power station according to an embodiment of the present invention includes:

[0040] The data acquisition module is used to collect the voltage, frequency and other parameters of the gravity energy storage power station grid connection point in real time; the module adopts high-precision sensors and high-speed data acquisition technology to ensure the accuracy and real-time nature of the data.

[0041] The calculation module is used to adjust the grid frequency value, determine the number of grid-connected / off-grid gravity energy storage units according to the collected data calculation system, generate corresponding energy storage or release instructions, and issue the total output / input power value of the gravity energy storage system.

[0042] The instruction generation and distribution module is used to generate power increase and decrease instructions for each converter based on the output of the calculation module, and send the instructions to the converter cooperation module through the high-speed communication network. This module uses advanced control algorithms to ensure the accuracy and speed of the instructions.

[0043] The converter cooperation module is connected to each converter of the gravity energy storage power station. After receiving the instruction, each converter is used to adjust the output power according to the instruction, so as to ensure the coordinated work between the converters and improve the overall response consistency.

[0044] The status monitoring and feedback module is used to monitor the overall operating status of the gravity energy storage power station and the performance indicators of the grid auxiliary services in real time, make adaptive adjustments based on the monitoring results, and feed back to the instruction generation and allocation module to achieve dynamic optimization of the system.

[0045] See also Figure 1 Based on the coordinated control system for a gravity energy storage power station of the present invention, the present invention also provides a coordinated control method for a gravity energy storage power station, which, according to some embodiments, includes the following steps:

[0046] Step S1, collecting parameters of the grid connection point of the gravity energy storage power station in real time through a data acquisition module.

[0047] Step S2, the calculation module calculates the required adjustment frequency of the power grid according to the objective function, and determines whether a gravity energy storage power station is needed to provide support for the power grid. If necessary, continue to step S3.

[0048] Step S3, the instruction generation and allocation module determines the grid-connected / off-grid gravity energy storage equipment according to the calculation result and the instruction generated by the value of the grid-required regulation frequency; specifically: the instruction generation and allocation module determines the calculated grid-required regulation frequency, and when it is determined that the grid-required regulation frequency is a positive number, the gravity energy storage system grid-connected unit is established, the instruction generation and allocation module generates corresponding energy storage or release instructions according to the control strategy, sends them to the converter cooperation module, and continues to execute step S4; when it is determined that the grid-required regulation frequency is a non-positive number, the number of grid-connected units of the gravity energy storage system is reduced, and the process returns to continue from step S2.

[0049] Step S4, the converter cooperation module sends instructions to each converter, so that the converter adjusts its output power according to the received instructions, so as to realize the cooperative work between the converters through the converter cooperation module. Preferably, step S4 specifically includes the following steps:

[0050] When multiple converters need to work together, the converter collaboration module exchanges information with each converter and the power grid through the communication network, adjusts the instructions to each converter according to the situation (for example, the power grid or a converter fails and the power distribution needs to be adjusted), and realizes collaborative decision-making to meet the needs and stability of the overall system; then, the converter collaboration module sends instructions to each converter;

[0051] Each converter receives one or more instructions through the communication interface; these instructions may be commands for tasks such as power adjustment and frequency stabilization; then, according to the received instructions, each converter adjusts its output power and / or frequency respectively; this process usually involves adjusting the control algorithm of the converter, such as PID control, fuzzy control, etc.;

[0052] It further includes feedback and optimization: in the process of adjusting the power output, the converter has a feedback mechanism so that further optimization can be performed according to the actual operating results; for example, the converter is connected to the state monitoring and feedback module through a communication network, and each converter and the corresponding gravity energy storage unit can provide feedback to the state monitoring and feedback module.

[0053] In this solution, the role of the converter collaboration module is to jointly determine the voltage and frequency of the grid when multiple converters are connected to the grid at the same time. In the event of a grid failure or a sudden change in power demand, the converter needs to respond quickly. Through the converter collaboration module, all converters can respond quickly as a whole to ensure the stability and reliability of the grid. If each converter receives commands and operates independently, it may cause unstable voltage and frequency of the grid; there are also special cases. For example, when a converter fails, other converters can compensate for its output through the converter collaboration module to ensure continuous power supply to the grid and avoid paralysis of the entire system due to a single converter failure.

[0054] Step S5, the status monitoring and feedback module monitors the operating status and performance indicators of the system in real time, and performs adaptive adjustment and optimization according to the monitoring results; and feeds back to the instruction generation and allocation module to achieve dynamic optimization of the system.

[0055] In some specific implementations, in step S2, the calculation module may use renewable energy fluctuation suppression and power demand of the power grid as the objective function:

[0056] Assume that the time for gravity energy storage to participate in smoothing the fluctuation of renewable energy is [t1, t2]. Since the power generation of renewable energy changes rapidly, its adjustment period is in units of 1 minute. In order to characterize the suppression effect of gravity energy storage on the fluctuation of renewable energy power generation, the optimization objective function f1 is established by minimizing the sum of squares of the difference in renewable energy power change after adjustment:

[0057]

[0058] In the formula, the subscript i represents the i-th period, P dg,i is the power generated by renewable energy, P G,i is the output power of the gravity energy storage system, P DG,i-1 is the output power value of renewable energy without gravity energy storage compensation, P DG,iIt is the output power value of renewable energy after gravity energy storage compensation.

[0059] Assume that gravity energy storage participates in the load balancing of the power grid throughout the whole process. Assume that the adjustment time is [t3, t4] and the time interval is 5 minutes. Based on the principle of minimizing the square of the instantaneous power deviation between supply and demand and the average deviation, the power demand matching objective function f2 of the power grid is established:

[0060]

[0061] Where P L,i is the load power, P avg It is the average value of the difference between supply and demand after energy storage is used to smooth it out.

[0062] In summary, the mathematical model of the minimum regulation frequency of the gravity energy storage grid-connected system is obtained by optimization:

[0063]

[0064] The difference between the output power of the gravity energy storage and the total output power reference value of the gravity energy storage device system and the required adjustment frequency value of the power grid are used as the control input of the gravity energy storage system. The control process can be expressed as follows:

[0065] P f =P ref +K g f t ,

[0066] Where P f is the overall compensation output power of the gravity energy storage system, P ref is the total output power reference value of the system, K g is the unit adjustment power of the gravity energy storage device, f t Adjust the frequency value required by the power grid.

[0067] In step S3, the instruction generation and distribution module can use a proportional control algorithm to set a proportional coefficient according to the overall needs of the system and the status of each converter, and then calculate the power that each converter should increase or decrease according to the proportional coefficient. The calculation formula is as follows:

[0068] ΔPi=K(P f -P c ),

[0069] Where ΔP_i is the power that the i-th converter should increase or decrease, K is the proportional coefficient, and P f is the overall compensation output power of the gravity energy storage system, P c is the total power of all current converters.

[0070] The specific calculation formula of the instruction generation and distribution module should be determined according to the actual application scenario and requirements. In addition, in order to improve the control accuracy and response speed, a variety of control strategies and methods can be combined to finely adjust the output power of the converter.

[0071] The main concept of the present invention is as follows. Gravity energy storage is to form a heavy flow of discrete heavy objects to generate electricity continuously. The transportation efficiency of gravity energy storage elements per unit time is low, and the power configuration is limited, which limits its energy storage capacity and cannot achieve large-scale and efficient energy storage. Therefore, it is necessary to centralize and coordinate the control of multiple gravity energy storage modules to build a GW-level gravity energy storage system. Since the gravity energy storage power station participates in grid auxiliary services, it needs to meet certain time delay conditions, especially the transient control of primary frequency modulation, which needs to be completed within hundreds of milliseconds. If there is no coordinated control system, it is difficult to make a large number of gravity energy storage modules synchronously output the corresponding power within hundreds of milliseconds. The working process of primary frequency modulation is that the gravity energy storage power station measures the voltage of the grid connection point, calculates the grid frequency and compares it with the reference value, and controls the gravity energy storage power station to actively perform energy storage or release to maintain the stability of frequency / voltage. If hundreds or thousands of converters in a gravity energy storage system measure each other and autonomously perform energy storage or release based on the measurement results, the values ​​of power increase or decrease of each converter will be different due to the different measurement errors and action time points of each converter, and even some converters will increase power while others will decrease power, and the overall response consistency index of the gravity energy storage power station will become poor. Therefore, a storage coordination control device is needed to measure the parameters of the gravity energy storage power station grid connection point, generate power increase and decrease instructions based on the measurement results, and distribute and notify them in all converters to complete the collaboration between converters and achieve the consistency of the overall response of the gravity energy storage power station.

Claims

1. A coordinated control system for a gravity energy storage power station, characterized in that: Included are: A data acquisition module, which is used to collect parameters of the gravity energy storage power station grid connection point in real time; A calculation module is used to calculate the grid frequency value adjusted by the system according to the collected data, determine the number of grid-connected / off-grid gravity energy storage units, generate corresponding energy storage or release instructions, and issue the total output / input power value of the gravity energy storage system; An instruction generation and distribution module, which is used to generate power increase and decrease instructions for each converter according to the output of the calculation module, and send the instructions to the converter cooperation module through a high-speed communication network; A converter cooperation module, which is used to enable each converter to adjust the output power according to the instruction after receiving the instruction; The status monitoring and feedback module is used to monitor the overall operating status of the gravity energy storage power station and the performance indicators of the grid auxiliary services in real time, make adaptive adjustments based on the monitoring results, and feed back to the instruction generation and allocation module to achieve dynamic optimization of the system.

2. A coordinated control method for a gravity energy storage power station, characterized in that: It adopts the coordinated control system for a gravity energy storage power station according to claim 1, which comprises the following steps: Step S1, collecting parameters of the grid connection point of the gravity energy storage power station in real time through a data acquisition module; Step S2, the calculation module calculates the required adjustment frequency of the power grid according to the objective function; Step S3, the instruction generation and allocation module determines the calculated required adjustment frequency of the power grid. When it is determined that the required adjustment frequency of the power grid is a positive number, the gravity energy storage system grid-connected unit is established, and the instruction generation and allocation module generates corresponding energy storage or energy release instructions according to the control strategy, sends them to the converter cooperation module, and continues to execute step S4; when it is determined that the required adjustment frequency of the power grid is a non-positive number, the number of grid-connected units of the gravity energy storage system is reduced, and the process returns to start from step S2; Step S4, the converter cooperation module sends instructions to each converter, so that the converter adjusts its output power according to the received instructions, so as to realize cooperative work between the converters through the converter cooperation module; Step S5: The status monitoring and feedback module monitors the operating status and performance indicators of the system in real time, and performs adaptive adjustment and optimization according to the monitoring results.

3. The coordinated control method for a gravity energy storage power station according to claim 2, characterized in that: In step S2, the calculation module takes renewable energy fluctuation suppression and power demand of the power grid as the objective function: Assume that the time that gravity energy storage participates in smoothing the fluctuation of renewable energy is [t1, t2]; In order to characterize the suppression effect of gravity energy storage on the fluctuation of renewable energy power generation, the optimization objective function f1 is established by minimizing the sum of squares of the difference in renewable energy power after adjustment: In the formula, the subscript i represents the i-th period, P dg,i is the power generated by renewable energy, P G,i is the output power of the gravity energy storage system, P DG,i-1 is the output power value of renewable energy without gravity energy storage compensation, P DG ,i is the output power value of renewable energy after gravity energy storage compensation; Assume that gravity energy storage participates in the load balancing of the power grid throughout the whole process; Assume that the adjustment time is [t3, t4]; Based on the principle of minimizing the square of the instantaneous power deviation between supply and demand and the average deviation, establish the power demand matching objective function f2 of the power grid: Where P L,i is the load power, P avg is the average value of the difference between supply and demand after energy storage is applied; In summary, the mathematical model of the minimum regulation frequency of the gravity energy storage grid-connected system is obtained by optimization: The difference between the output power of the gravity energy storage and the total output power reference value of the gravity energy storage device system and the required frequency adjustment value of the power grid are used as the control input of the gravity energy storage system. The control process is expressed as follows: P f =P ref +K g f t , Where P f is the overall compensation output power of the gravity energy storage system, P ref is the total output power reference value of the system, K g is the unit adjustment power of the gravity energy storage device, f t Adjust the frequency value required by the power grid.

4. The coordinated control method for a gravity energy storage power station according to claim 2, characterized in that: In step S3, the instruction generation and distribution module uses a proportional control algorithm to set a proportional coefficient according to the overall requirements of the system and the status of each converter, and then calculates the power that each converter should increase or decrease according to the proportional coefficient; the calculation formula is as follows: ΔP_i=K(P f -P c ), Where ΔP_i is the power that the i-th converter should increase or decrease, K is the proportional coefficient, P f is the overall compensation output power of the gravity energy storage system, P c is the total power of all current converters.

5. The coordinated control method for a gravity energy storage power station according to claim 2, characterized in that: Step S4 further comprises: The converter collaboration module exchanges information through the communication network, adjusts the instructions to each converter, and implements collaborative decision-making to meet the needs and stability of the overall system; the converter collaboration module sends instructions to each converter; Each converter receives one or more instructions via the communication interface, and then according to the received instructions, the converter adjusts its output power and / or frequency; In the process of adjusting the power output, the converter has a feedback mechanism to further optimize according to the actual operating results.

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