A method and system for improving comprehensive performance of energy storage auxiliary frequency modulation in a thermal power plant

Abstract

The application relates to the technical field of power system frequency modulation, in particular to a thermal power plant energy storage auxiliary frequency modulation comprehensive performance improvement method and system. The method comprises the following steps: judging whether the absolute value of the deviation between the actual output of a thermal power unit and an AGC frequency modulation instruction reaches a first threshold value; if not, controlling an energy storage system to perform first direction power regulation to increase the absolute value of the deviation, so that the absolute value of the deviation reaches the first threshold value; wherein the first direction is opposite to the regulation direction required for tracking the AGC frequency modulation instruction; after the absolute value of the deviation reaches the first threshold value, controlling the energy storage system to perform second direction power regulation and cooperating with the thermal power unit to track the AGC frequency modulation instruction; wherein the second direction is opposite to the first direction. According to the application, the energy storage system actively pre-regulates the deviation in the reverse direction to quickly trigger the energy storage positive cooperation, so that the frequency modulation response speed and the comprehensive performance index are improved.

Description

Technical Field

[0001] This application relates to the field of power system frequency regulation technology, specifically a method and system for improving the comprehensive performance of frequency regulation auxiliary energy storage in thermal power plants. Background Technology

[0002] Under the trend of energy transition, renewable energy has developed rapidly. However, due to the instability and volatility of its power generation, it is difficult to independently undertake the task of stable power supply. Thermal power generation, as the traditional pillar of the power system, provides stable power supply, but it has shortcomings in response speed and frequency regulation / peak shaving. Traditional primary frequency regulation relies on speed regulation systems, which are difficult to flexibly cope with complex load demands. Against this background, the thermal power-storage joint frequency regulation mode has emerged. This mode combines the stability of thermal power with the flexibility of energy storage systems. Thermal power units continuously support output, while energy storage systems quickly suppress high-frequency, short-term power fluctuations. The two work together to maintain frequency stability, becoming a research hotspot in the field of new power system frequency regulation.

[0003] Currently, in combined thermal power and energy storage frequency regulation projects, the comprehensive performance index (K-value) of the energy storage-assisted frequency regulation system is the key to evaluating its performance, directly affecting economic benefits and frequency regulation efficiency. However, existing technologies have many shortcomings, such as imperfect combined thermal power and energy storage control strategies and unreasonable battery charging and discharging modes, resulting in the energy storage system's frequency regulation potential not being fully explored, and the K-value failing to reach the ideal level.

[0004] Therefore, how to improve the comprehensive performance index K value and achieve a more flexible and reliable power supply is an urgent problem to be solved in the field of thermal power and energy storage joint frequency regulation. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for improving the overall performance of energy storage-assisted frequency regulation in thermal power plants in order to solve at least one of the above-mentioned technical problems.

[0006] This application achieves the above objectives through the following technical solutions: A method for improving the overall performance of frequency regulation auxiliary energy storage in thermal power plants, applied to energy storage systems, includes the following steps: Obtain the AGC frequency modulation command and determine the deviation between the actual output of the thermal power unit and the AGC frequency modulation command; Determine whether the absolute value of the deviation reaches a first threshold; If the target is not reached, the energy storage system is controlled to perform a first-direction power adjustment to increase the absolute value of the deviation so that the absolute value of the deviation reaches the first threshold; wherein, the first direction is opposite to the adjustment direction required to track the AGC frequency modulation command; When the absolute value of the deviation reaches the first threshold, the energy storage system is controlled to perform second-direction power regulation and work in coordination with the thermal power unit to track the AGC frequency regulation command; wherein the second direction is opposite to the first direction.

[0007] Furthermore, the method also includes: after the coordinated output reaches the target output required by the AGC frequency modulation command, controlling the output of the energy storage system to continuously decrease, while controlling the output of the thermal power unit to synchronously increase, until the output of the energy storage system exits, and the thermal power unit independently maintains the target output.

[0008] Furthermore, before the energy storage system performs the first directional power regulation, it also includes: The current state of charge of the energy storage system is obtained, and it is determined whether the current state of charge is within a preset safe range, and whether the predicted state of charge after the first directional power adjustment is still within the preset safe range. Determine whether there is an effective deviation between the AGC frequency modulation command and the actual output of the thermal power unit, and whether the AGC frequency modulation command is a sudden change command or a frequency disturbance trigger command; Determine whether the power value of the first direction power adjustment simultaneously meets the following conditions: not exceeding the rated power of energy storage, not exceeding the current maximum allowable adjustment power, and not exceeding the grid and unit safe ramp rate limits; Determine whether the thermal power unit is in AGC frequency regulation mode and is not in a fault, load limit or maintenance state, and whether the current output is not in the upper or lower load dead zone; Real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals to confirm that there are no abnormalities; Determine whether all the above conditions are met simultaneously; if yes, then allow the first direction power adjustment; if not, then prohibit its execution.

[0009] Furthermore, the preset safety range is defined as the lowest state of charge threshold ≤ state of charge ≤ highest state of charge threshold.

[0010] Furthermore, before the energy storage system performs the first directional power regulation, it also includes: Obtain the current frequency modulation response speed index; If the current frequency regulation response speed index is lower than the preset response threshold, or if the energy storage system determines that the response time needs to be shortened, the first direction power regulation will be triggered first.

[0011] Furthermore, when the absolute value of the deviation reaches the first threshold, the energy storage system continues to perform the second directional power adjustment for a duration of T1, where T1 > 60 seconds.

[0012] Furthermore, the duration T1 is 600 seconds.

[0013] Furthermore, the method also includes: Throughout the entire process of performing the first directional power regulation, the real-time state of charge of the energy storage system is monitored. When the real-time state of charge exceeds the preset safe range, the first directional power regulation is immediately terminated and the second directional power regulation is switched. When a fault, protection action, or emergency stop signal is detected, the first direction power regulation is immediately terminated, and a safety protection shutdown procedure is executed.

[0014] A comprehensive performance enhancement system for frequency regulation auxiliary in thermal power plants, applied to energy storage systems, the enhancement system comprising: The instruction acquisition module is used to acquire AGC frequency modulation instructions and determine the deviation between the actual output of the thermal power unit and the AGC frequency modulation instructions; A deviation judgment module is used to determine whether the absolute value of the deviation reaches a first threshold. An energy storage control module is configured to control the energy storage system to perform a first-direction power adjustment when the absolute value of the deviation does not reach the first threshold, so as to increase the absolute value of the deviation to reach the first threshold; wherein the first direction is opposite to the adjustment direction required to track the AGC frequency modulation command; The unit coordination module is used to control the energy storage system to perform second-direction power regulation and coordinate with the thermal power unit to output power in order to track the AGC frequency regulation command when the absolute value of the deviation reaches the first threshold; wherein, the second direction is opposite to the first direction, and the second direction is the adjustment direction required to track the AGC frequency regulation command.

[0015] Furthermore, the lifting system also includes: The safety monitoring module is used to determine whether all of the following constraints are met before the energy storage system performs the first directional power regulation: The current state of charge of the energy storage system is obtained, and it is determined whether the current state of charge is within a preset safe range, and whether the predicted state of charge after the first directional power adjustment is still within the preset safe range. Determine whether there is an effective deviation between the AGC frequency modulation command and the actual output of the thermal power unit, and whether the AGC frequency modulation command is a sudden change command or a frequency disturbance trigger command; Determine whether the power value of the first direction power adjustment simultaneously meets the following conditions: not exceeding the rated power of energy storage, not exceeding the current maximum allowable adjustment power, and not exceeding the grid and unit safe ramp rate limits; Determine whether the thermal power unit is in AGC frequency regulation mode and is not in a fault, load limit or maintenance state, and whether the current output is not in the upper or lower load dead zone; Real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals to confirm that there are no abnormalities; If all constraints are met, the first-direction power adjustment is allowed; otherwise, it is prohibited.

[0016] The beneficial effects of this application are as follows: This application increases the deviation through active reverse pre-adjustment to quickly trigger positive energy storage coordination, combines multi-dimensional safety constraints to ensure operational safety, and extends the positive output time of energy storage to achieve smooth power handover. At the same time, it dynamically optimizes the adjustment strategy according to the response speed index, effectively improving the frequency regulation response speed and comprehensive performance index, and solving the problems of response lag, power jump and safety risks in traditional methods. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for improving the overall performance of energy storage-assisted frequency regulation in thermal power plants according to one embodiment of this application; Figure 2 This is a schematic diagram of a method for improving the overall performance of energy storage-assisted frequency regulation in thermal power plants according to one embodiment of this application. Figure 3 This is a schematic diagram of the structure of a thermal power plant energy storage-assisted frequency regulation integrated performance improvement system according to one embodiment of this application; Figure 4 This is a schematic diagram of the power plant energy storage system structure in Example 3; Figure 5 This is a diagram of the power plant energy storage auxiliary frequency regulation topology for Example 3; Figure 6 This is a comparison chart of K values ​​before and after the strategy modification in Example 3. Detailed Implementation

[0018] The content of this application will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the content of this application, and are not intended to imply any limitation on the scope of this application.

[0019] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0020] As mentioned earlier, in a combined thermal power and energy storage frequency regulation system, thermal power units and energy storage systems form a complementary and synergistic architecture: thermal power units play a continuous supporting role, tracking power changes after commands are issued, replacing energy storage to maintain power balance, and charging and replenishing energy storage during load reduction periods; while energy storage systems play a role in instantaneous response, quickly suppressing high-frequency, short-term power fluctuations during periods of power shortage caused by sudden load changes. The synergistic effect of both combines the advantages of fast response speed, high regulation accuracy, good economy, and strong stability, avoiding the large frequency fluctuations caused by single thermal power generation and overcoming the shortcomings of single energy storage with limited capacity and poor sustainability, achieving a synergistic effect of 1+1>2.

[0021] However, the actual frequency regulation performance of this system needs to be evaluated and assessed using scientific quantitative indicators. The K-value (comprehensive performance index) is the core quantitative parameter for measuring the frequency regulation capability of a thermal power plant's energy storage auxiliary frequency regulation system. Its value directly determines the energy storage system's grid connection eligibility, the probability of winning frequency regulation bids, and its market profitability, serving as a crucial qualification for participating in grid auxiliary frequency regulation services. Therefore, improving the K-value is not only a goal of technical optimization but also a core path to enhancing the direct competitiveness of the energy storage system in the auxiliary frequency regulation market and maximizing its profitability.

[0022] The calculation of the K value follows the following weighting: K = 0.5K1 + 0.25K2 + 0.25K3 Wherein, K is the comprehensive performance index; K1 is the response speed, which reflects the dynamic tracking level of the power output when facing frequency changes; K2 is the adjustment rate, which reflects the dynamic tracking level of the power output when facing frequency changes; K3 is the adjustment accuracy, which reflects the system's ability to accurately track frequency modulation commands; the weights of the three are 0.5, 0.25, and 0.25, respectively.

[0023] Given the decisive role of the K-value in grid connection access, market competitiveness, and profitability, and considering that it is constrained by response speed, regulation rate, and regulation accuracy, this application proposes a comprehensive performance enhancement scheme for frequency regulation assisted by energy storage in thermal power plants. This scheme aims to improve the performance of each sub-indicator (K1, K2, and K3) through technological optimization and coordinated control strategies, thereby achieving an overall leap in the K-value and maximizing frequency regulation profitability.

[0024] Example 1 Figure 1 This is a flowchart illustrating a method for improving the overall performance of energy storage-assisted frequency regulation in thermal power plants, according to one embodiment of this application. Figure 2 This is a schematic diagram illustrating the principle of a method for improving the overall performance of frequency regulation auxiliary energy storage in thermal power plants, according to one embodiment of this application. Figure 1-2 As shown, according to one embodiment of this application, a method for improving the overall performance of energy storage-assisted frequency regulation in thermal power plants includes the following steps: Step S102: Obtain the AGC frequency regulation command and determine the deviation between the actual output of the thermal power unit and the AGC frequency regulation command; Step S104: Determine whether the absolute value of the deviation reaches the first threshold. Step S106: If the target is not reached, control the energy storage system to perform power regulation in the first direction to increase the absolute value of the deviation so that the absolute value of the deviation reaches the first threshold; wherein, the first direction is opposite to the regulation direction required to track the AGC frequency modulation command; Step S108: When the absolute value of the deviation reaches the first threshold, the energy storage system is controlled to perform power regulation in the second direction and work together with the thermal power unit to track the AGC frequency regulation command; wherein, the second direction is opposite to the first direction and the second direction is the regulation direction required to track the AGC frequency regulation command.

[0025] This embodiment proposes a method to improve the overall performance of energy storage-assisted frequency regulation in thermal power plants. By reconstructing the response timing logic of the energy storage system to AGC frequency regulation commands, the traditional passive waiting response mode is transformed into an active reverse pre-adjustment control mode. Specifically, before the absolute value of the deviation reaches the trigger condition for the energy storage system to start positive output, the energy storage system does not remain silent but actively outputs power in the opposite direction to the target adjustment. Utilizing the inherent advantage of rapid response of electrochemical energy storage, it amplifies the power deviation between the actual output of the thermal power unit and the AGC frequency regulation command, thereby compressing the time window required for the deviation to reach the trigger threshold and creating preconditions for subsequent positive coordinated output. When the absolute value of the deviation reaches the first threshold, the energy storage system switches to the second direction of power regulation, that is, coordinated output in the same direction as the thermal power unit to track the AGC frequency regulation command.

[0026] This application improves the overall performance index K value in terms of response speed by reconstructing the response timing logic of the energy storage system, actively reverse pre-adjusting to shorten the deviation trigger time, and then achieving seamless connection through forward collaborative output.

[0027] According to one embodiment of this application, the enhancement method further includes: In step S110, after the coordinated output reaches the target output required by the AGC frequency regulation command, the output of the energy storage system is controlled to continuously decrease, while the output of the thermal power unit is controlled to increase synchronously until the output of the energy storage system is withdrawn, and the thermal power unit independently maintains the target output.

[0028] In this embodiment, after the combined output of thermal power and energy storage reaches the target output required by the AGC frequency regulation command, the power handover logic during the energy storage system's exit phase is reconstructed, transforming the traditional rigid switching mode into a smooth transition mode. The energy storage system includes multiple energy storage units, each charging or discharging at maximum power. The energy storage system schedules a corresponding number of energy storage units based on actual demand.

[0029] The output of the energy storage system continues to decrease as the real-time difference between the AGC frequency regulation command and the actual output of the unit decreases synchronously. The output of the thermal power unit gradually increases on the original basis, gradually replacing the power deficit of the energy storage system in a gradual climbing manner, until the output of the energy storage system completely withdraws, and the thermal power unit independently maintains the target output.

[0030] The energy storage system in this application uses closed-loop feedback regulation based on the real-time deviation between the AGC frequency regulation command and the actual output of the unit to ensure that the sum of the combined output of thermal power and energy storage always approaches the target output value at any given moment.

[0031] According to one embodiment of this application, before the energy storage system performs the first directional power regulation in step S106, it is necessary to determine and confirm that the following constraints are met simultaneously: SOC constraints: The current state of charge (SOC) of the energy storage system must be within a preset safe range, and the predicted state of charge after the first direction power regulation must also be within a preset safe range. AGC frequency modulation command direction constraint: There must be an effective deviation between the AGC frequency modulation command and the actual output of the thermal power unit, and the AGC frequency modulation command must be a sudden change command or a frequency disturbance triggered command; Power limit constraints: The power value of the first direction power regulation must simultaneously meet the following requirements: not exceeding the rated power of energy storage, not exceeding the current maximum allowable regulation power, and not exceeding the grid and unit safe ramp rate limits; Unit operation constraints: The thermal power unit must be in AGC frequency regulation mode and not in a fault, load limit or maintenance state, and the current output must not be in the upper or lower load dead zone; Safety interlocking conditions: The real-time monitored battery temperature and energy storage converter status are normal, and no protection action signal or emergency shutdown signal is triggered.

[0032] If any constraint is not met, the first direction power regulation is prohibited.

[0033] The preset safe range is defined as the minimum state of charge threshold ≤ state of charge ≤ maximum state of charge threshold.

[0034] In this embodiment, upon receiving the AGC frequency regulation command, the energy storage system simultaneously performs multi-dimensional condition judgments: the SOC constraint ensures that the current SOC of the energy storage system is within the safe range of 10% to 90%, and the predicted SOC after reverse output will not exceed the boundary of this range, fundamentally avoiding the risks of overcharging and over-discharging; the AGC frequency regulation command direction constraint limits reverse output to only when there is an effective deviation between the command and the actual load of the unit, and the command is a sudden change command or a frequency disturbance triggered command, preventing malfunctions under steady-state no-command conditions; the power limit constraint ensures that the power output is always within the dual boundaries of the equipment's carrying capacity and the safe operation of the power grid; the unit operation constraint requires the unit to be in AGC frequency regulation mode and not in a fault, load-limited, or maintenance state, while the current output avoids the upper and lower load dead zones, ensuring the physical feasibility of coordinated regulation of thermal power and energy storage; the safety interlocking condition constraint constructs the last line of defense by real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals. When all of the above conditions are met simultaneously, the energy storage system can perform reverse output, actively increasing the difference between the unit load and the command.

[0035] This application ensures the safety and feasibility of reverse power output from the energy storage system by setting multi-dimensional constraints, including SOC, command direction, power limit, unit operation, and safety interlocking, before the energy storage system performs reverse power output, thus creating favorable conditions for subsequent coordinated frequency regulation of thermal power and energy storage.

[0036] According to one embodiment of this application, before the energy storage system performs the first directional power regulation in step S106, the method further includes: Obtain the current frequency modulation response speed index; If the current frequency regulation response speed index is lower than the preset response threshold, or if the energy storage system determines that the response time needs to be shortened, the first direction power regulation will be triggered first.

[0037] In this embodiment, the reverse output triggering strategy of the energy storage system introduces a dynamic priority determination mechanism, incorporating frequency regulation performance indicators as a precondition for decision-making into the response logic. The system acquires the current frequency regulation response speed indicator K1 in real time and dynamically compares it with a preset response threshold. This preset threshold can be set to 2.0 points or other suitable values ​​based on grid assessment standards or historical operating data. When K1 is lower than this threshold, it indicates that the current response speed has become a core bottleneck restricting the improvement of comprehensive performance indicators. The system prioritizes triggering the reverse output mechanism, actively amplifying the power deviation to compress the response trigger time and achieve targeted repair of the K1 indicator.

[0038] When the energy storage system determines that there is an objective need to shorten the response time under the current frequency regulation conditions, it prioritizes reverse output, enabling the rapid adjustment capability of the energy storage system to be released in advance in terms of timing, ensuring that it seizes the initiative in response during the critical frequency regulation window. For example, situations such as: sudden changes in command amplitude exceeding the preset gradient, frequency deviation rate exceeding the normal fluctuation range, or the grid dispatching side making explicit requirements on response timeliness.

[0039] This application ensures that reverse output is not triggered indiscriminately in all deviation scenarios, but rather focuses on specific working conditions where there is room for improvement in response speed or where timeliness is urgently required.

[0040] According to one embodiment of this application, the enhancement method further includes: when the absolute value of the deviation reaches a first threshold, the energy storage system continuously performs the second directional power adjustment for a duration of T1, and T1 > 60 seconds.

[0041] Preferably, the duration T1 is 600 seconds.

[0042] In this embodiment, the duration T1 of the positive collaborative output phase of the energy storage system is set to an extended window of more than 60 seconds, preferably 600 seconds, to solve the problem of power jump and secondary fluctuation of grid frequency caused by the sudden withdrawal of the energy storage system after 60 seconds of continuous output in the traditional strategy.

[0043] In the traditional model, energy storage maintains a fixed output for 60 seconds after reaching the target output before ceasing to respond. The generating unit must then independently undertake the subsequent ramp-up and replenishment tasks. This application significantly extends the energy storage's output time to 600 seconds and constructs a dynamic coordination mechanism within this extended window period, where the energy storage output decreases and the generating unit output increases. As the real-time difference between the AGC frequency regulation command and the actual generating unit output decreases synchronously, the thermal power unit gradually increases its output until it completely replaces the energy storage, forming a smooth power handover curve.

[0044] This application extends the positive collaborative output time of the energy storage system to achieve smooth power handover, effectively solving the problems of power jump and secondary fluctuations in grid frequency caused by the sudden withdrawal of energy storage in traditional strategies.

[0045] According to one embodiment of the present invention, the lifting method further includes: Throughout the entire process of performing the first-direction power regulation, the real-time state of charge of the energy storage system is monitored. When the real-time state of charge exceeds the preset safe range, the first direction power regulation is immediately terminated and the second direction power regulation is switched. When a fault, protection action, or emergency stop signal is detected, the first direction power regulation is immediately terminated, and a safety protection shutdown procedure is executed.

[0046] In this embodiment, safety monitoring is performed throughout the entire reverse power output process of the energy storage system, including: real-time closed-loop monitoring of the state of charge (SOC). When the real-time SOC of the energy storage system exceeds a preset safe range (e.g., below 10% or above 90%), reverse power output is terminated and forward power regulation is switched. The reverse correction effect of forward power on the SOC is used to bring it back to the safe range, avoiding irreversible damage to the battery body caused by overcharging and over-discharging. When high battery temperature, energy storage converter failure, protection action, or emergency shutdown signal is detected, the energy storage system terminates reverse power output and executes a safety protection shutdown procedure, cutting off the energy storage power output and reporting to the dispatching terminal to prevent reverse power injection under fault conditions from exacerbating grid disturbances.

[0047] This application effectively ensures the safe operation of the energy storage system and avoids damage to the battery and grid by real-time monitoring of the state of charge and fault signals throughout the entire reverse power output process of the energy storage system, timely terminating abnormal adjustments and switching or shutting down the system.

[0048] Example 2 Figure 3 This is a schematic diagram of the structure of a thermal power plant energy storage-assisted frequency regulation integrated performance improvement system according to one embodiment of this application. Figure 3 As shown, according to one embodiment of this application, a comprehensive performance enhancement system for auxiliary frequency regulation in thermal power plants using energy storage is applied to an energy storage system. The enhancement system includes: The instruction acquisition module is used to acquire AGC frequency regulation instructions and determine the deviation between the actual output of the thermal power unit and the AGC frequency regulation instructions; The deviation judgment module is used to determine whether the absolute value of the deviation reaches the first threshold. The energy storage control module is used to control the energy storage system to perform power regulation in a first direction when the absolute value of the deviation has not reached a first threshold, so as to accelerate the absolute value of the deviation to reach the first threshold; wherein, the first direction is opposite to the regulation direction required to track the AGC frequency modulation command; The unit coordination module is used to control the energy storage system to perform second-direction power regulation when the absolute value of the deviation reaches the first threshold, and to coordinate with the thermal power unit to output power to track the AGC frequency regulation command; wherein, the second direction is opposite to the first direction, and the second direction is the adjustment direction required to track the AGC frequency regulation command.

[0049] Preferably, the lifting system further includes: The safety monitoring module is used to determine whether all of the following constraints are met before the energy storage system performs first-direction power regulation: The current state of charge of the energy storage system is obtained, and it is determined whether the current state of charge is within a preset safe range, and whether the predicted state of charge after the first directional power regulation is still within the preset safe range. Determine whether there is an effective deviation between the AGC frequency regulation command and the actual output of the thermal power unit, and whether the AGC frequency regulation command is a sudden change command or a frequency disturbance trigger command; Determine whether the power value of the first direction power regulation simultaneously meets the following requirements: not exceeding the rated power of energy storage, not exceeding the current maximum allowable regulation power, and not exceeding the grid and unit safe ramp rate limits; Determine whether the thermal power unit is in AGC frequency regulation mode and is not in a fault, load limit or maintenance state, and whether the current output is not in the upper or lower load dead zone; Real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals to confirm that there are no abnormalities; If all constraints are met, the first direction power regulation is allowed; otherwise, it is prohibited.

[0050] This embodiment proposes a comprehensive performance enhancement system for frequency regulation assisted by energy storage in thermal power plants. The command acquisition module and deviation judgment module analyze AGC frequency regulation commands in real time and quantify the tracking deviation of the thermal power unit. The energy storage control module and the unit coordination module switch the energy storage output direction based on the deviation threshold judgment result. The safety monitoring module integrates multiple dimensions such as state of charge constraints, command feature recognition, power boundary verification, unit operating condition judgment, and equipment status monitoring, allowing reverse output only when all constraints are simultaneously met. The modules are interconnected via a data bus. The reverse output power value output by the energy storage control module and the coordinated output timing parameters output by the unit coordination module are fed back to the safety monitoring module for closed-loop verification, ensuring dynamic matching between control commands and constraints, and achieving synergistic optimization of frequency regulation performance improvement and operational safety management.

[0051] This application achieves synergistic optimization of frequency regulation performance improvement and operational safety management by real-time command analysis, deviation quantification, switching of energy storage output direction, and multi-dimensional integration of safety monitoring.

[0052] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the system described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0053] Example 3 Figure 4 This is a schematic diagram of the power plant energy storage system structure in Example 3. Figure 5 This is a topology diagram of power plant energy storage-assisted frequency regulation in Example 3. To verify the technical effect of this application, the comprehensive performance improvement scheme for thermal power plant energy storage-assisted frequency regulation in this application was applied to the 30MW / 30MWh energy storage system of Power Plant A. The energy storage system includes 12 walk-in battery compartments, 6 transformers, and is connected to a 6kV high-voltage plant service transformer, serving a 1000MW thermal power unit. The energy storage system selectively follows one of the two units according to the actual situation.

[0054] In the old frequency regulation strategy, after receiving the AGC frequency regulation command, the energy storage system did not respond. Instead, it waited until the difference between the existing load of the thermal power unit and the AGC command reached a preset value before starting positive power output, operating simultaneously with the thermal power unit. Once the preset target was reached, the energy storage system continued output for 60 seconds before ceasing to respond, after which the thermal power unit would independently ramp up to the command value. Under this strategy, the response speed... With a maximum score of 3 points, it can only get about 1.8 points, requiring adjustment precision. You can only get about 0.6 points out of a possible 1 point.

[0055] After adopting the technical solution of this application, upon receiving the AGC frequency regulation command, the energy storage system performs reverse output, increasing the difference between the unit's existing load and the AGC frequency regulation command, and reducing the time for the difference to reach the preset value. Subsequently, the energy storage system performs forward output simultaneously with the unit. This change will improve the response speed index. Increased to 2.8. After reaching the preset target, the energy storage system will continuously output power for 600 seconds. During this period, the output of the thermal power unit gradually increases, while the output of the energy storage system decreases synchronously with the difference between the AGC frequency regulation command value and the unit command value, eliminating the situation where the energy storage system momentarily stops outputting power. This change will improve the adjustment accuracy. Increased to 0.8.

[0056] Figure 6 This is a comparison chart of K values ​​before and after the strategy modification in Example 3. Figure 6 As shown, the comprehensive performance index K value of energy storage-assisted frequency regulation using the two strategies was monitored within the same time period. The comprehensive performance index K value of energy storage-assisted frequency regulation using the scheme of this application increased from about 1.3 to more than 1.8, which is a significant improvement.

[0057] The energy storage system using the technical solution of this application significantly reduces the trigger threshold time, giving the subsequent energy storage system a head start in positive output. After reaching the preset frequency regulation target, the energy storage system increases the continuous output time, avoiding power fluctuations caused by sudden energy storage withdrawal, improving regulation accuracy, and significantly improving the overall performance indicators of the energy storage system.

[0058] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0059] It should be understood that the sequence number of each step in the invention content and embodiments of this application does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A method for improving the overall performance of frequency regulation auxiliary energy storage in thermal power plants, applied to energy storage systems, characterized in that, Includes the following steps: Obtain the AGC frequency modulation command and determine the deviation between the actual output of the thermal power unit and the AGC frequency modulation command; Determine whether the absolute value of the deviation reaches a first threshold; If the target is not reached, the energy storage system is controlled to perform a first-direction power adjustment to increase the absolute value of the deviation so that the absolute value of the deviation reaches the first threshold; wherein, the first direction is opposite to the adjustment direction required to track the AGC frequency modulation command; When the absolute value of the deviation reaches the first threshold, the energy storage system is controlled to perform second-direction power regulation and work in coordination with the thermal power unit to track the AGC frequency regulation command; wherein the second direction is opposite to the first direction.

2. The method according to claim 1, characterized in that, The method further includes: after the coordinated output reaches the target output required by the AGC frequency modulation command, controlling the output of the energy storage system to continuously decrease, while controlling the output of the thermal power unit to synchronously increase, until the output of the energy storage system exits, and the thermal power unit independently maintains the target output.

3. The method according to claim 1, characterized in that, Before the energy storage system performs the first directional power regulation, it also includes: The current state of charge of the energy storage system is obtained, and it is determined whether the current state of charge is within a preset safe range, and whether the predicted state of charge after the first directional power adjustment is still within the preset safe range. Determine whether there is an effective deviation between the AGC frequency modulation command and the actual output of the thermal power unit, and whether the AGC frequency modulation command is a sudden change command or a frequency disturbance trigger command; Determine whether the power value of the first direction power adjustment simultaneously meets the following conditions: not exceeding the rated power of energy storage, not exceeding the current maximum allowable adjustment power, and not exceeding the grid and unit safe ramp rate limits; Determine whether the thermal power unit is in AGC frequency regulation mode and is not in a fault, load limit or maintenance state, and whether the current output is not in the upper or lower load dead zone; Real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals to confirm that there are no abnormalities; Determine whether all the above conditions are met simultaneously; if yes, then allow the first direction power adjustment; if not, then prohibit its execution.

4. The method according to claim 3, characterized in that, The preset safety range is defined as the lowest state of charge threshold ≤ state of charge ≤ highest state of charge threshold.

5. The method according to claim 3, characterized in that, Before the energy storage system performs the first directional power regulation, it also includes: Obtain the current frequency modulation response speed index; If the current frequency regulation response speed index is lower than the preset response threshold, or if the energy storage system determines that the response time needs to be shortened, the first direction power regulation will be triggered first.

6. The method according to claim 1, characterized in that, When the absolute value of the deviation reaches the first threshold, the energy storage system continues to perform the second directional power adjustment for a duration of T1, where T1 > 60 seconds.

7. The method according to claim 6, characterized in that, The duration T1 is 600 seconds.

8. The method according to claim 1, characterized in that, The method further includes: Throughout the entire process of performing the first directional power regulation, the real-time state of charge of the energy storage system is monitored. When the real-time state of charge exceeds the preset safe range, the first directional power regulation is immediately terminated and the second directional power regulation is switched. When a fault, protection action, or emergency stop signal is detected, the first direction power regulation is immediately terminated, and a safety protection shutdown procedure is executed.

9. A comprehensive performance enhancement system for frequency regulation auxiliary in thermal power plants, applied to energy storage systems, characterized in that, The lifting system includes: The instruction acquisition module is used to acquire AGC frequency modulation instructions and determine the deviation between the actual output of the thermal power unit and the AGC frequency modulation instructions; A deviation judgment module is used to determine whether the absolute value of the deviation reaches a first threshold. An energy storage control module is configured to control the energy storage system to perform a first-direction power adjustment when the absolute value of the deviation does not reach the first threshold, so as to increase the absolute value of the deviation to reach the first threshold; wherein the first direction is opposite to the adjustment direction required to track the AGC frequency modulation command; The unit coordination module is used to control the energy storage system to perform second-direction power regulation and coordinate with the thermal power unit to output power in order to track the AGC frequency regulation command when the absolute value of the deviation reaches the first threshold; wherein, the second direction is opposite to the first direction, and the second direction is the adjustment direction required to track the AGC frequency regulation command.

10. The lifting system according to claim 9, characterized in that, The lifting system also includes: The safety monitoring module is used to determine whether all of the following constraints are met before the energy storage system performs the first directional power regulation: The current state of charge of the energy storage system is obtained, and it is determined whether the current state of charge is within a preset safe range, and whether the predicted state of charge after the first directional power adjustment is still within the preset safe range. Determine whether there is an effective deviation between the AGC frequency modulation command and the actual output of the thermal power unit, and whether the AGC frequency modulation command is a sudden change command or a frequency disturbance trigger command; Determine whether the power value of the first direction power adjustment simultaneously meets the following conditions: not exceeding the rated power of energy storage, not exceeding the current maximum allowable adjustment power, and not exceeding the grid and unit safe ramp rate limits; Determine whether the thermal power unit is in AGC frequency regulation mode and is not in a fault, load limit or maintenance state, and whether the current output is not in the upper or lower load dead zone; Real-time monitoring of battery temperature, energy storage converter status, protection action signals, and emergency shutdown signals to confirm that there are no abnormalities; If all constraints are met, the first-direction power adjustment is allowed; otherwise, it is prohibited.

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