Thermal Power Unit-Energy Storage Coupled Frequency Regulation System for Improving Power Grid Frequency Stability

Abstract

The present invention relates to the technical field of power system frequency, and discloses a thermal power unit - energy storage coupled frequency modulation system for improving the frequency stability of the power grid. The system includes a thermal power unit module, an energy storage system module, an energy management and distribution control module, and a communication and monitoring module. The thermal power unit provides a frequency stability basis through inertial response and power regulation, and the energy storage system compensates for frequency deviations in a fast response manner. The energy management module dynamically adjusts the power distribution ratio between the thermal power unit and the energy storage system based on an optimized objective function to achieve efficient coordinated frequency modulation. The output power and state of charge of the energy storage system are controlled by constraint conditions. The communication and monitoring module collects real-time data on grid frequency, load fluctuations, and energy storage status, and generates frequency modulation control signals to be sent to each module. By combining the stability of the thermal power unit and the fast response characteristics of the energy storage system, the present invention significantly improves the response speed and regulation accuracy of grid frequency regulation, while reducing the frequency modulation cost.

Description

Technical Field

[0001] The present invention relates to the technical field of power system frequency modulation, and particularly to a thermal power unit - energy storage coupled frequency modulation system for improving the frequency stability of the power grid. Background Art

[0002] With the large - scale access of renewable energy, especially the rapid development of intermittent energy sources such as wind energy and solar energy, the problem of frequency stability of the power grid has become increasingly prominent. The traditional power system is based on large - scale thermal power units, which have a large rotational inertia and stable output power. Therefore, for a long time in the past, the frequency regulation of the power grid mainly relied on thermal power units. However, with the continuous increase in the proportion of new energy power generation, the following problems and deficiencies have gradually emerged in this traditional frequency modulation mode:

[0003] The main frequency modulation means of thermal power units are primary frequency modulation and secondary frequency modulation. On the one hand, primary frequency modulation depends on the rotational inertia of the unit, and its frequency regulation response has a certain time lag, usually unable to quickly meet the sudden fluctuation requirements of the power grid frequency. On the other hand, secondary frequency modulation is mainly achieved by adjusting the output power of thermal power units, and the regulation speed is limited by the ramp rate of the unit (usually at the MW / s level), unable to cope with the rapid load changes brought about by new energy fluctuations. Therefore, thermal power units have obvious deficiencies in rapid frequency regulation.

[0004] New energy power generation (such as wind energy and photovoltaic) has strong volatility and intermittency because its output power is significantly affected by meteorological conditions. When the proportion of new energy access is relatively high, the dynamic change range of the power grid load increases, and the occurrence frequency and amplitude of frequency deviation both increase significantly. Moreover, new energy itself lacks inertia support and cannot directly participate in the inertial response and primary frequency modulation of the power grid, further exacerbating the challenge of power grid frequency stability.

[0005] Energy storage systems (such as lithium - ion batteries, flywheel energy storage, etc.) can effectively make up for the deficiencies of thermal power units in rapid frequency modulation due to their fast response characteristics. However, the initial investment cost of energy storage systems is relatively high, and they are easily affected by the impact of frequent power changes on their lifespan during long - term operation. In addition, the energy capacity and power output of energy storage systems are limited, making it difficult to balance high - power and long - time regulation requirements when used alone. Therefore, relying solely on energy storage systems is not an economically feasible solution.

[0006] Although the cooperative frequency modulation scheme of thermal power units and energy storage systems has gradually attracted attention, the existing technologies still have deficiencies in the following aspects:

[0007] Optimization problem of power distribution strategy: How to reasonably distribute power between thermal power units and energy storage systems to balance the response speed, frequency modulation accuracy, and operating cost is a difficult point in current technologies.

[0008] Dynamic response characteristic matching: The response speed of thermal power units is relatively slow, while energy storage systems can respond quickly. There are significant differences in their dynamic characteristics, and there is still a lack of mature solutions for how to achieve efficient dynamic coordinated control.

[0009] Long-term operation economy and stability: During the coordinated frequency regulation process, how to reduce the frequent start-stop of energy storage systems to extend their service life, and at the same time avoid the efficiency reduction and wear problems caused by the frequent regulation of thermal power units, is still a challenge to be solved.

[0010] The coordinated frequency regulation system needs to collect and process various data such as grid frequency, thermal power unit output power, and energy storage status in real time, and transmit control signals through the communication module. However, the existing communication and monitoring systems may be insufficient in terms of real-time performance and accuracy. Especially when sudden fluctuations occur in the power grid, delays and errors may lead to impaired frequency regulation effects.

[0011] In summary, the existing frequency regulation technologies have many deficiencies in terms of rapid response ability, economy, and coordinated control strategies, and cannot fully meet the frequency stability requirements for the high-proportion access of new energy to the power grid. Therefore, there is an urgent need for an innovative technology for the coordinated frequency regulation of thermal power units and energy storage systems to give full play to the stability of thermal power units and the rapid response characteristics of energy storage systems, solve the prominent problems in the current technology, and achieve more efficient, economical, and stable frequency regulation.

[0012] Therefore, we urgently need to design a thermal power unit - energy storage coupled frequency regulation system to improve the power grid frequency stability to solve the above problems. Summary of the Invention

[0013] The purpose of the present invention is to solve the existing technical problems mentioned in the above background technology and provide a thermal power unit - energy storage coupled frequency regulation system for improving the power grid frequency stability.

[0014] The above object of the present invention is achieved as follows:

[0015] The solution of the present invention provides a thermal power unit - energy storage coupled frequency regulation system for improving the power grid frequency stability, including the following modules:

[0016] Thermal power unit frequency regulation module: It provides the basic frequency regulation ability through the thermal power unit, and its output power satisfies the following dynamic equation:

[0017] ;

[0018] Wherein, is the output power of the thermal power unit at time moment, with the unit of MW;

[0019] is the initial output power of the thermal power unit, with the unit of MW;

[0020] is the maximum power climbing rate of the thermal power unit, with the unit of MW / s;

[0021] is the control signal of the thermal power unit, with the range of [0, 1];

[0022] Energy storage system module: includes battery energy storage or flywheel energy storage system, and its output power and state of charge satisfy the following dynamic equations and constraint conditions:

[0023] ;

[0024] ;

[0025] , ;

[0026] wherein, is the output power of the energy storage system at time moment, with the unit of MW;

[0027] is the control signal of the energy storage system, with the range of [0, 1];

[0028] is the state of charge of the energy storage system, with the unit of MWh;

[0029] is the initial state of charge;

[0030] , are the minimum and maximum state of charge limits of the energy storage system respectively;

[0031] is the maximum power output of the energy storage system, with the unit of MW;

[0032] Energy management and distribution control module: Dynamically adjusts the output powers of the thermal power unit and the energy storage system according to the grid frequency deviation to satisfy the following power balance equation:

[0033] ;

[0034] wherein, is the deviation between the grid load power and the generation power, with the unit of MW;

[0035] is the grid frequency deviation, with the unit of Hz;

[0036] Communication and monitoring module: used to monitor the power grid frequency fluctuation, energy storage state and operating state of thermal power units, and transmit control signals 、 。

[0037] On the other hand, the energy management and distribution control module controls the power distribution of thermal power units and energy storage systems based on the optimization objective function The objective function is as follows:

[0038] ;

[0039] Wherein, is the total system operation cost, with the unit of MW 2 ·s;

[0040] is the time period for optimizing frequency modulation, with the unit of s;

[0041] and are the power penalty coefficients of thermal power units and energy storage systems, both of which are dimensionless;

[0042] is the power grid frequency deviation, with the unit of Hz.

[0043] On the other hand, the output power of the thermal power unit at time satisfies the following dynamic constraint conditions:

[0044] ;

[0045] Wherein, is the maximum power climbing rate of the thermal power unit, with the unit of MW / s;

[0046] is the power change rate of the thermal power unit, with the unit of MW / s.

[0047] On the other hand, the output power of the energy storage system at the time satisfies the following dynamic constraint conditions:

[0048] ;

[0049] Wherein, is the maximum power output of the energy storage system, with the unit of MW.

[0050] On the other hand, the state of charge of the energy storage system satisfies the following constraints:

[0051] ;

[0052] Wherein, is the state of charge of the energy storage system at time , with the unit of MWh;

[0053] is the minimum state of charge of the energy storage system, with the unit of MWh;

[0054] is the maximum state of charge of the energy storage system, with the unit of MWh.

[0055] On the other hand, the power distribution ratio between the thermal power unit and the energy storage system is determined by the optimization variable and satisfies the following power distribution equation:

[0056] ;

[0057] where is the output power of the thermal power unit at time , with the unit of MW;

[0058] is the output power of the energy storage system at time , with the unit of MW;

[0059] is the deviation between the grid load power and the generation power, with the unit of MW;

[0060] is the power distribution ratio coefficient, ranging from [0, 1], dimensionless, representing the proportion of the thermal power unit in the power distribution.

[0061] On the other hand, the optimization variable satisfies the following iterative formula:

[0062] ;

[0063] where is the power distribution ratio coefficient at the next moment, ranging from [0, 1], dimensionless; is the power distribution ratio coefficient at the current moment, ranging from [0, 1], dimensionless;

[0064] is the learning rate, representing the step size of iterative optimization, with the unit of dimensionless;

[0065] is the objective function with respect to , with the unit of MW 2 ;

[0066] It is the objective function for system optimization, representing the comprehensive index of frequency deviation and power cost, with the unit of MW 2 ·s

[0067] On the other hand, the grid frequency deviation satisfies the following dynamic change equation:

[0068] ;

[0069] where is the frequency deviation of the power grid at time , with the unit of Hz;

[0070] is the time derivative of the frequency deviation, with the unit of Hz / s;

[0071] is the grid time constant, representing the time characteristics of frequency regulation response, with the unit of s;

[0072] is the grid inertia constant, representing the inertial anti-disturbance ability of the power grid to frequency changes, with the unit of MW·S 2 / Hz;

[0073] is the deviation between the grid load power and the generation power, with the unit of MW.

[0074] On the other hand, the final response of the frequency deviation satisfies the following closed-loop control formula:

[0075] ;

[0076] where is the frequency deviation of the power grid at time , with the unit of Hz;

[0077] is the frequency deviation at the initial moment of the power grid, with the unit of Hz;

[0078] is the grid time constant, representing the time characteristics of frequency regulation response, with the unit of s;

[0079] is the grid inertia constant, representing the inertial anti-disturbance ability of the power grid to frequency changes, with the unit of MW·S 2 / Hz;

[0080] is the current moment, with the unit of s;

[0081] is the integration variable, representing the intermediate variable of time integration, with the unit of s;

[0082] is the load power deviation at a certain time, with the unit of MW; At a certain moment, the load power deviation, unit MW;

[0083] On the other hand, the energy management and distribution control module adopts a model predictive control algorithm, and according to the dynamic characteristics of thermal power units , the state of charge of the energy storage system and the frequency deviation optimize the power distribution.

[0084] The present invention also provides a thermal power unit - energy storage coupled frequency modulation method for improving the frequency stability of the power grid. The specific steps include:

[0085] Real - time monitor the frequency deviation of the power grid and the power deviation , that is: ;

[0086] Optimize and calculate the power distribution of thermal power units and the output of the energy storage system ;

[0087] Generate a control signal and send it to the thermal power unit and the energy storage system;

[0088] Feedback closed - loop control, adjust the power output until the frequency deviation converges to the target range.

[0089] Compared with the prior art, the present invention has the following beneficial effects:

[0090] 1. Through the collaborative frequency modulation of thermal power units and energy storage systems, the technical solution of the present invention combines the stable inertial response of thermal power units with the fast dynamic regulation ability of energy storage systems; when frequency fluctuations occur, the energy storage system can quickly respond to achieve timely compensation for frequency deviation; at the same time, the thermal power unit gradually takes over the regulation task to provide continuous power support; this collaborative mechanism significantly improves the response speed and regulation accuracy of power grid frequency regulation, and effectively addresses the frequency disturbance problems caused by new energy fluctuations;

[0091] 2. Through the optimized energy management strategy, the technology of the present invention reasonably distributes the power output tasks between thermal power units and energy storage systems, which not only reduces the impact of frequent start - stop of the energy storage system on its lifespan, but also avoids the problems of reduced efficiency and wear caused by excessive regulation of thermal power units; the dynamic adjustment of power distribution takes into account both fast response and operation economy, enabling the system to significantly reduce the frequency modulation cost while meeting the frequency stability requirements;

[0092] 3. The technology of the present invention solves the problem that the traditional frequency modulation method cannot cope with the volatility of new energy, and realizes the organic combination of grid frequency stability and flexibility through coordinated frequency modulation; especially in the scenario of large-scale access of new energy, this technology can effectively absorb the volatility characteristics of new energy, ensure the stable operation of the grid frequency, and at the same time provide technical support for building a green and intelligent grid with a high proportion of renewable energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0094] Figure 1 It is a system block diagram of a thermal power unit - energy storage coupled frequency modulation system for improving the grid frequency stability of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0095] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0096] The following will Figure 1 in conjunction with the drawings

[0097] The solution of the embodiment of the present invention is a thermal power unit - energy storage coupled frequency modulation system for improving the grid frequency stability, including the following modules:

[0098] 1. Thermal power unit module: The thermal power unit dynamically adjusts the output power according to the frequency deviation and the load deviation , and the control signal is , satisfying the following dynamic formula:

[0099] ;

[0100] Wherein, is the output power of the thermal power unit at time , with the unit of MW; is the initial power output of the thermal power unit, with the unit of MW;

[0101] is the maximum power climbing rate of the thermal power unit, with the unit of MW / s; is the control signal of the thermal power unit, with the range [0, 1] and dimensionless; is the time variable, with the unit of s.

[0102] 2. Energy storage system module: The energy storage system quickly responds to the grid frequency fluctuation, and its output power is regulated by the control signal to satisfy:

[0103] ;

[0104] where, is the output power of the energy storage system at time with the unit of MW; is the control signal of the energy storage system, with the range [0, 1] and dimensionless; is the maximum output power of the energy storage system, with the unit of MW.

[0105] The state of charge of the energy storage system has the dynamic change formula as:

[0106] ;

[0107] where, is the state of charge of the energy storage system at time with the unit of MWh;

[0108] is the output power of the energy storage system at time with the unit of MW; is the time variable, with the unit of s;

[0109] . The power and state of charge of the energy storage system need to satisfy the following constraints:

[0110] , ;

[0111] where, , are the minimum and maximum state of charge limits of the energy storage system, respectively, with the unit of MWh.

[0112] 3. Energy management and distribution control module: The energy management module determines the power distribution ratio of the thermal power unit and the energy storage system based on the optimization objective function , then:

[0113] ;

[0114] where, is the system optimization target value, unit: MW 2 ·s; is the frequency deviation of the power grid at time in Hz;

[0115] 、 are the output powers of the thermal power unit and the energy storage system at time in MW; 、 are the power penalty coefficients of the thermal power unit and the energy storage system, dimensionless;

[0116] is the time period of the frequency modulation optimization, unit: s.

[0117] Power distribution formula: , ;

[0118] where is the power distribution ratio of the thermal power unit, in the range [0, 1], dimensionless; is the load power deviation of the power grid at time in MW.

[0119] Distribution ratio Dynamic update formula:

[0120] ;

[0121] where 、 are the power distribution ratios at time and time respectively, dimensionless; is the learning rate, controlling the iteration step, dimensionless; is the partial derivative of the objective function with respect to the distribution ratio, unit: MW 2 .

[0122] 4. Communication and monitoring module: The communication and monitoring module monitors the frequency deviation of the power grid 、the load power deviation 、the energy storage state in real time, and generates control signals and which are sent to the thermal power unit and the energy storage system respectively.

[0123] The following is a specific description in combination with several embodiments:

[0124] Embodiment 1: The initial value of the power grid frequency , the target frequency . The frequency deviation , the thermal power unit and the energy storage system work together to regulate the frequency.

[0125] Calculate the load power deviation using the formula:

[0126] ;

[0127] where, is the grid load power deviation, unit MW; , then the conversion coefficient between frequency and power deviation is:

[0128] ;

[0129] Calculate to get:

[0130] ;

[0131] Power distribution optimization:

[0132] Initial power distribution ratio , then:

[0133] ;

[0134] ;

[0135] Generate control signals: Thermal power unit control signal:

[0136] , ;

[0137] Calculate to get:

[0138] ;

[0139] Energy storage system control signal:

[0140] , ;

[0141] Calculate to get:

[0142] ;

[0143] Frequency restoration: The thermal power unit and the energy storage system work together to restore the frequency to 49.95 Hz within 10 seconds.

[0144] Example 2: The new energy fluctuation causes the grid frequency to drop to , the target frequency ; The frequency deviation ; The energy storage system responds preferentially.

[0145] Calculate the load power deviation: ;

[0146] Parameter: , ;

[0147] Calculated as: ;

[0148] Energy storage dominant power distribution: Initial distribution ratio , then

[0149] ;

[0150] ;

[0151] Generate control signal: Control signal of thermal power unit:

[0152] , ;

[0153] ;

[0154] Control signal of energy storage system:

[0155] , ;

[0156] ;

[0157] Energy storage state of charge update: Initial state , then:

[0158] ;

[0159] Frequency recovery: The energy storage system acts quickly and restores the frequency to 49.85 Hz within 5 seconds.

[0160] Example 3: The grid inertia is high (M = 10 MW\cdops 2 / Hz), and the frequency fluctuation is slow. Target frequency , initial frequency , deviation .

[0161] Calculate the load power deviation:

[0162] ;

[0163] Parameter: , .

[0164] Calculated as:

[0165] ;

[0166] Thermal power dominant power distribution:

[0167] Initial allocation ratio , then:

[0168] , ;

[0169] Generate control signals:

[0170] Control signals for thermal power units:

[0171] , ;

[0172] ;

[0173] Control signals for energy storage systems:

[0174] , ;

[0175] ;

[0176] Frequency restoration: Within 15 seconds, the frequency is restored to 49.98 Hz.

[0177] Example 4: During the long-term frequency regulation process, the state of charge of the energy storage needs to be maintained within a reasonable range to avoid over-discharge or over-charging. Assume the state of charge range of the energy storage system is .

[0178] The current frequency deviation is , and the target frequency is .

[0179] Calculation of load power deviation:

[0180] ;

[0181] Among them, is the load power deviation, in MW; is the frequency regulation coefficient, , in units of MW / Hz; ;

[0182] Calculated:

[0183] ;

[0184] Optimization of power distribution: The initial allocation ratio is set to , then:

[0185] ;

[0186] ;

[0187] Dynamic update of energy storage state of charge:

[0188] Using the formula: ;

[0189] Wherein, is the state of charge of the energy storage system at time , in units of MWh; is the output power of the energy storage system, in units of MW; is the time step, in units of s; initial state ;

[0190] Update calculation:

[0191] ;

[0192] Long-term optimal scheduling: Assuming that the frequency deviation decreases gradually every second, then:

[0193] Second second: , ;

[0194] Power allocation: , ;

[0195] State of charge update: ;

[0196] Third second: , the frequency returns to normal, and the energy storage system stops outputting power:

[0197] ;

[0198] Result analysis: Through reasonable power allocation and dynamic state of charge regulation, the energy storage system maintains a stable state of charge during long-term operation, avoids overcharging and discharging, and at the same time completes the rapid restoration of the grid frequency.

[0199] Initial state: ; Final state: .

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A thermal power unit - energy storage coupled frequency regulation system for improving the frequency stability of the power grid, characterized in that, It includes the following modules: Thermal power unit frequency modulation module: It provides the basic frequency regulation ability through the thermal power unit, and its output power P g (t) satisfies the following dynamic equation: Among them, P g (t) is the output power of the thermal power unit at time t, with the unit of MW; P g (0) is the initial output power of the thermal power unit, with the unit of MW; R g is the maximum power climbing rate of the thermal power unit, with the unit of MW / s; u g (t) is the control signal of the thermal power unit, and its range is [0, 1]; Energy storage system module: including battery energy storage or flywheel energy storage system, with its output power P s (t) and state of charge E s (t) satisfying the following dynamic equations and constraint conditions: Among them, P s (t) is the output power of the energy storage system at time t, with the unit of MW; u s (t) is the control signal of the energy storage system, and its range is [0, 1]; E s (t) is the state of charge of the energy storage system, in MWh; E s (0) is the initial charged state; E min and E max are the minimum and maximum state of charge limits of the energy storage system, respectively; The maximum power output of the energy storage system, in MW; Energy management and distribution control module: Dynamically adjusts the output power of thermal power units and energy storage systems according to the grid frequency deviation Δf(t) to satisfy the following power balance equation: P g (t) + P s (t) = ΔP(t); Where, ΔP(t) is the deviation between the grid load power and the generation power, with the unit of MW; Δf(t) is the grid frequency deviation, with the unit of Hz; Communication and monitoring module: used to monitor the power grid frequency fluctuations, energy storage status and the operating status of thermal power units, and transmit control signals u g (t), u s (t); The energy management and distribution control module controls the power distribution of thermal power units and energy storage systems based on the optimization objective function J. The objective function is: Among them, J is the total operating cost of the system, with the unit of MW 2 ·s; T is the time period of optimized frequency modulation, with the unit of s; λ1 and λ2 are the power penalty coefficients of thermal power units and energy storage systems, both dimensionless; Δf(t) is the grid frequency deviation, with the unit of Hz; The output power P of the thermal power unit at time t g (t) satisfies the following dynamic constraint conditions: Among them, R g is the maximum power ramp rate of the thermal power unit, with the unit of MW / s; is the power change rate of the thermal power unit, with the unit of MW / s; the power distribution ratio between the thermal power unit and the energy storage system is determined by the optimization variable α(t), satisfying the following power distribution equation: P g I(t) = α(t)ΔP(t); Among them, P g (t) is the output power of the thermal power unit at time t, with the unit of MW; P s (t) is the output power of the energy storage system at time t, with the unit of MW; ΔP(t) is the deviation between the grid load power and the generation power, with the unit of MW; α(t) is the power distribution ratio coefficient, with the range of [0, 1], dimensionless, representing the proportion of thermal power units in power distribution; The optimization variable α(t) satisfies the following iterative formula: Where, α(t + 1) is the power distribution ratio coefficient at the next moment, with the range of [0, 1], dimensionless; α(t) is the power distribution ratio coefficient at the current moment, with the range of [0, 1], dimensionless; η is the learning rate, representing the step size of iterative optimization, dimensionless; is the partial derivative of the objective function J with respect to α(t), with the unit of MW 2 ; $J$ is the objective function for system optimization, representing the comprehensive index of frequency deviation and power cost, with the unit of MW 2 ·s; the grid frequency deviation $\Delta f(t)$ satisfies the following dynamic change equation: Where, Δf(t) is the frequency deviation of the grid at time t, with the unit of Hz; is the time derivative of the frequency deviation, with the unit of Hz / s; τ is the grid time constant, representing the time characteristics of frequency regulation response, with the unit of s; M is the grid inertia constant, representing the inertial anti-disturbance ability of the grid to frequency changes, with the unit of MW·S 2 / Hz; ΔP(t) is the deviation between the grid load power and the generation power, with the unit of MW; The final response of the frequency deviation satisfies the following closed-loop control formula: Where, Δf(t) is the frequency deviation of the grid at time t, with the unit of Hz; Δf0 is the frequency deviation at the initial moment of the grid, with the unit of Hz; τ is the grid time constant, representing the time characteristics of frequency regulation response, with the unit of s; $M$ is the grid inertia constant, representing the inertial anti-disturbance ability of the grid to frequency changes, with the unit of MW·S 2 / Hz; t is the current moment, with the unit of s; u is the integration variable, representing the intermediate variable of time integration, with the unit of s; ΔP(u) is the load power deviation at time u, with the unit of MW; The energy management and distribution control module adopts a model predictive control algorithm to optimize power distribution according to the dynamic characteristics R of the thermal power unit g , the state of charge E s (t) of the energy storage system, and the frequency deviation Δf(t).

2. The thermal power unit - energy storage coupled frequency modulation system for improving the frequency stability of the power grid according to claim 1, characterized in that The output power P of the energy storage system at time t s satisfies the following dynamic constraint conditions: Among them, is the maximum power output of the energy storage system, with the unit of MW.

3. The thermal power unit - energy storage coupled frequency modulation system for improving the frequency stability of the power grid according to claim 1, characterized in that, The state of charge E s (t) of the energy storage system satisfies the following constraints: E min ≤E s (t)≤E max ; Among them, E s (t) is the state of charge of the energy storage system at time t, in MWh; E min is the minimum state of charge of the energy storage system, in MWh; E max is the maximum state of charge of the energy storage system, in MWh.

4. The frequency regulation method of the thermal power unit-energy storage coupled frequency regulation system according to any one of claims 1 to 3, characterized in that, The specific steps include: Real-time monitor the grid frequency deviation Δf(t) and power deviation ΔP(t); Optimize the calculation of the power distribution P g (t) of the thermal power unit and the output P s (t); Generate the control signal u g (t) and u s (t) and send them to the thermal power unit and the energy storage system; Feedback closed-loop control, adjust the power output until the frequency deviation Δf(t) converges to the target range.

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