Frequency modulation method and system for deep peak regulation of coal power unit

Abstract

The invention relates to the technical field of coal electricity decoupling of an electrode boiler and electrochemical energy storage in cogeneration of a coal power unit, in particular to a frequency modulation method and system for deep peak regulation of the coal power unit. The method comprises the following steps: instruction receiving: when a coal power unit is in a peak regulation state, acquiring a power grid frequency modulation instruction, the frequency modulation instruction comprising an AGC power instruction, and the AGC power instruction comprising total power P; determining an electrode boiler regulation power set value and a coal power set value by load response, respectively sending the values to corresponding execution systems, and determining energy storage output frequency modulation power according to the actual execution power of the execution systems; operating parameters of each execution system are monitored in real time through state optimization, when the energy storage SOC is smaller than 30% or larger than 90%, the power of a coal power unit is adjusted, and final actual power is calculated through PMU collection and fed back to a power grid to complete adjustment of a closed loop. The problems that an existing electrode boiler and electrochemical energy storage cannot be cooperatively controlled, and the operation efficiency of a thermoelectric cogeneration coal generator set in a thermoelectric coupling state is low are solved.

Description

A frequency regulation method and system for deep peak shaving in coal-fired power units Technical Field

[0001] This invention relates to the field of coal-fired power decoupling technology for electrode boilers and electrochemical energy storage in coal-fired power units, and particularly to a frequency regulation method and system for deep peak shaving in coal-fired power units. Background Technology

[0003] In existing technologies, electrode boilers, with their high efficiency (conversion efficiency ≥99%), rapid response (0-100% power switching within 20 minutes), and stepless power regulation (0-100% load range), have been applied to the decoupling retrofit of coal-fired power units. By directly converting electrical energy into heat energy and connecting it to the industrial steam supply mains, the peak-shaving capacity of the unit's power generation load is released, allowing the minimum technical output of the unit to be reduced to below 30% of the rated load. On the other hand, electrochemical energy storage systems have advantages such as fast response speed (millisecond level) and high regulation accuracy.

[0004] However, existing technologies typically implement deep peak shaving and rapid frequency regulation as two independent functions. When the unit reduces to a deep peak shaving state (e.g., 30% of rated load) through a combined electrode boiler, its own power generation load regulation margin is small, making it difficult to meet the rapid load response requirements of frequency regulation. If energy storage frequency regulation is used alone, the long-term high-load operation of coal-fired power units is not economically viable due to factors such as boiler combustion stability and the need to supply industrial steam. Existing technologies have not yet achieved coordinated control of electrode boilers and electrochemical energy storage, resulting in coal-fired power units being unable to stably and efficiently participate in frequency regulation ancillary services under deep peak shaving conditions, thus restricting the unit's market competitiveness and overall profitability. Summary of the Invention

[0005] This invention provides a frequency regulation method and system for deep peak shaving of coal-fired power units, in order to solve the problem that existing electrode boilers and electrochemical energy storage cannot be controlled in a coordinated manner, and to overcome the problem of low operating efficiency of cogeneration coal-fired power units under thermoelectric coupling.

[0006] This invention is achieved through the following technical solution, providing a frequency regulation method for deep peak shaving of coal-fired power units, comprising the following steps: Instruction reception: when the coal-fired power unit is in peak shaving state, a frequency regulation instruction from the power grid is obtained, the instruction including an AGC power instruction, which includes a total power P; Load response: the setpoint for the electrode boiler regulation power and the setpoint for the coal-fired power unit are determined and sent to the corresponding execution systems, and the energy storage output frequency regulation power is determined based on the actual execution power of the execution systems; State optimization: the operating parameters of each execution system are monitored in real time, and when the energy storage SOC is less than 30% or greater than 90%, the power of the coal-fired power unit is adjusted, the final actual power is calculated through the PMU and fed back to the power grid, completing the regulation closed loop.

[0007] Specifically, the load response steps are as follows: The electrode boiler regulating power setpoint P is set according to the AGC power command. e When 105MW≦P≦125MW, P e The capacity is 60MW; when 125MW < P < 130MW, P e The capacity is 50MW; when 130MW≦P≦150MW, P e The capacity is 40MW; when 150MW < P < 155MW, P e The capacity is 30MW; when 155MW≦P≦175MW, P e The capacity is 20MW; when 175MW < P < 180MW, P e The value is 10MW; when 180MW≤P≤185MW, P e The value is 0MW; the determined P e The value is sent to the electrode boiler control system, the coal-fired power unit DCS, and the energy storage EMS; the coal-fired power unit DCS receives the grid AGC command and adds the total power P to P. e The power setpoint of the coal-fired power unit is then generated, driving the coal-fired power unit to output the actual power P. unit ;Based on P by energy storage EMS unit P e In conjunction with the AGC command, calculate the energy storage frequency regulation action amount ΔP, and use ΔP as the energy storage output frequency regulation power P. fm △P is calculated using the following formula: △P = P - (P unit - P e When ΔP is positive, energy storage discharge occurs; when ΔP is negative, energy storage charging occurs.

[0008] Specifically, the final actual power of the PMU is P actual P is calculated using the following formula. actual = P unit - P e +P fm ;where P unit To drive the coal-fired power unit to output actual power, P fm For energy storage output frequency modulation power, P e The power setting value for the electrode boiler.

[0009] Specifically, the power setpoint of the coal-fired power unit is maintained in the range of 105MW-195MW, only accepting slow power changes with a change rate of ≤2% / min; the power setpoint of the electrode boiler is dynamically adjusted according to the total power P, accepting medium-speed power changes with a change rate of ≤5% / min, and the adjustment range is 0MW-60MW; the frequency regulation power output of the energy storage unit responds to high-frequency, small-amplitude power fluctuations with a response time of ≤50ms, and the adjustment range is -9MW to +9MW, ensuring that the frequency regulation command tracking accuracy reaches ±2MW.

[0010] Specifically, before receiving the grid frequency regulation command, the system is started up to put the electrode boiler into hot standby mode, the energy storage SOC is adjusted to 50%-70%, and then a communication self-test is performed.

[0011] Specifically, in the state optimization step, the specific steps for adjusting the power of the coal-fired power unit are as follows: when the energy storage SOC is less than 30% or greater than 90%, gradually reduce the energy storage output frequency regulation power P. fm Until it drops to 0; synchronously adjust the power setpoint of the coal-fired power unit, increasing the amount by P. fm The reduction amount; continuous monitoring of SOC, when SOC recovers to the range of 30%-70%, gradually restore the energy storage frequency regulation function; after state optimization, the system is shut down, after the grid command ends, the electrode boiler is reduced to the minimum power to maintain hot standby, the energy storage SOC recovers to 50%-70%, and the coal-fired power unit load recovers to the base value.

[0012] The present invention also relates to a frequency regulation system for deep peak shaving of coal-fired power units, comprising: a coal-fired power unit equipped with a coal-fired power unit DCS for regulating its own power and monitoring its operating status; an electrode boiler subsystem for converting electrical energy into thermal energy, comprising an electrode boiler and an electrode boiler control system; an electrochemical energy storage subsystem comprising an energy storage converter and an energy storage EMS; and a collaborative control subsystem communicatively connected to the coal-fired power unit DCS, the electrode boiler control system, and the energy storage EMS for data exchange and unified control.

[0013] Specifically, the collaborative control subsystem includes: a data acquisition module for acquiring real-time operating status data of the coal-fired power unit, the electrode boiler subsystem, and the electrochemical energy storage subsystem, and receiving grid dispatch instructions; a load allocation module for generating power allocation instructions for each subsystem based on the grid dispatch instructions and the operating status of each subsystem; an instruction execution module for distributing the power allocation instructions to the coal-fired power unit, the electrochemical energy storage subsystem, and the electrode boiler subsystem; and a status monitoring module for monitoring the overall operational safety of the system.

[0014] Specifically, the status monitoring module is configured to monitor the power status of the electrochemical energy storage subsystem, and when the power status exceeds a preset range, trigger the load distribution module to adjust the power command of the electrode boiler subsystem, so as to indirectly manage the state of charge of the electrochemical energy storage subsystem.

[0015] Specifically, the power generation output end of the coal-fired power unit is connected to the power grid, and the heating end is connected to the industrial steam supply main pipe. The electrode boiler subsystem also includes a transformer that supplies power to the electrode boiler. The power input end of the electrode boiler subsystem is connected to the plant power system of the coal-fired power unit, and the heat output end of the electrode boiler subsystem is connected to the industrial steam supply main pipe to convert electrical energy into heat energy.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses DCS as the core of coal-fired power unit load regulation, superimposed electrode boiler power to realize the joint response of "unit + electrode boiler", uses EMS as the core of energy storage scheduling, realizes the coordinated regulation of "energy storage and the former two" through data difference calculation, uses PMU as the core of data collection and feedback, ensures that the grid side obtains accurate actual power data, completes the closed-loop control of AGC mode, and solves the problem that energy storage frequency regulation and electrode boiler independent systems cannot directly participate in AGC mode through DCS+EMS+PMU linkage, realizes the joint regulation of coal-fired power unit, energy storage frequency regulation and electrode boiler, and ensures that the actual power accurately responds to the grid command; (2) Using the method and system of the present invention, the present invention innovatively uses electrode boiler to convert electrical energy into thermal energy so that coal-fired power unit can continuously meet the grid frequency regulation requirements under deep peak shaving conditions, and utilizes electrochemical The energy storage subsystem and the collaborative control subsystem, under the constraints of the thermoelectric coupling contradiction of the cogeneration unit, can meet the grid frequency regulation auxiliary service requirements under the deep peak shaving condition of the coal-fired power unit; (3) For different power change characteristics, the peak shaving and frequency regulation power is decomposed into the coal-fired power unit bearing slow power change, the electrode boiler bearing medium-speed power change and the energy storage responding to high-frequency and small-amplitude power fluctuations. Through the hierarchical allocation of time scale and power range, the response speed and regulation accuracy are taken into account, and the frequency regulation tracking accuracy reaches ±2MW; (4) The power of the electrode boiler is dynamically adjusted to make room for energy storage charging and discharging, avoiding frequency regulation interruption caused by the battery's state of charge exceeding the limit, extending the cycle life of the energy storage battery, and reducing operating costs. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the load response and state optimization process of a frequency regulation method for deep peak shaving of coal-fired power units according to the present invention; Figure 2 is a communication topology diagram of a frequency regulation system for deep peak shaving of coal-fired power units according to the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this application, unless otherwise stated, "multiple" means two or more.

[0020] Example 1: This invention provides a frequency regulation method for deep peak shaving of coal-fired power units. When the coal-fired power unit is in a deep peak shaving state (105MW≤power generation≤185MW) and receives a frequency regulation command, a layered response strategy of "coarse adjustment of electrode boiler + fine adjustment of energy storage" is adopted, including the following steps: system startup, putting the electrode boiler into hot standby state, which can be started within 20 minutes, adjusting the energy storage SOC (State of Charge, battery state of charge) to 50%-70%, and then performing a communication self-test of the system.

[0021] Command reception: When the unit is in peak shaving mode, obtain the grid frequency regulation command. The frequency regulation command includes the AGC (Automatic Generation Control) power command, which includes the total power P.

[0022] Load response determines the setpoint for the regulating power of the electrode boiler and the setpoint for the power of the coal-fired power unit, and sends them to the corresponding execution systems. The energy storage output frequency regulation power is determined based on the actual execution power of the execution systems.

[0023] As shown in Figure 1, the specific steps of the load response are as follows: setting the electrode boiler regulating power setpoint P. e The load response process involves sending the load to the electrode boiler control system, the coal-fired power unit's DCS (distributed control system), and the energy storage EMS (energy management system). Specifically, the load response steps involve setting the electrode boiler's regulating power setpoint P according to the AGC power command. e When 105MW≦P≦125MW, P e The capacity is 60MW; when 125MW < P < 130MW, P e The capacity is 50MW; when 130MW≦P≦150MW, P e The capacity is 40MW; when 150MW < P < 155MW, P e The capacity is 30MW; when 155MW≦P≦175MW, P e The capacity is 20MW; when 175MW < P < 180MW, P e The value is 10MW; when 180MW≤P≤185MW, P eThe value is 0MW; the determined P e The value is sent to the electrode boiler control system, the coal-fired power unit DCS, and the energy storage EMS; the coal-fired power unit DCS receives the grid AGC command and adds the total power P to P. e The power setpoint of the coal-fired power unit is then generated, driving the coal-fired power unit to output the actual power P. unit ;Based on P by energy storage EMS unit P e In conjunction with the AGC command, calculate the energy storage frequency regulation action amount ΔP, and use ΔP as the energy storage output frequency regulation power P. fm △P is calculated using the following formula: △P = P - (P unit - P e When ΔP is positive, energy storage discharge occurs; when ΔP is negative, energy storage charging occurs.

[0024] The power setpoint of the coal-fired power unit is maintained in the range of 105MW-195MW, only handling slow power changes with a change rate of ≤2% / min; the power setpoint of the electrode boiler is dynamically adjusted according to the total power P, handling medium-speed power changes with a change rate of ≤5% / min, and the adjustment range is 0MW-60MW; the frequency regulation power output of the energy storage unit responds to high-frequency, small-amplitude power fluctuations with a response time of ≤50ms, and the adjustment range is -9MW to +9MW, ensuring that the frequency regulation command tracking accuracy reaches ±2MW.

[0025] State optimization involves real-time monitoring of the operating parameters of each execution system. When the energy storage SOC is less than 30% or greater than 90%, the power of the coal-fired power unit is adjusted. The final actual power is collected and calculated through the PMU (Power Management Unit) and fed back to the grid to complete the regulation closed loop.

[0026] Specifically, the final actual power of the PMU is P actual P is calculated using the following formula. actual = P unit - P e +P fm ;where P unit To drive the coal-fired power unit to output actual power, P fm For energy storage output frequency modulation power, P e The power setting value for the electrode boiler.

[0027] Specifically, in this embodiment, the steps for adjusting the power of the coal-fired power unit are as follows: when the energy storage SOC is less than 30% or greater than 90%, gradually reduce the energy storage output frequency regulation power P. fm Until it drops to 0; synchronously adjust the power setpoint of the coal-fired power unit, increasing the amount by P. fmThe reduction in energy consumption; continuous monitoring of SOC, and gradual restoration of energy storage frequency regulation function when SOC recovers to the range of 30%-70%.

[0028] When the system shuts down and the grid command ends, the electrode boilers reduce to minimum power to maintain thermal standby, the energy storage SOC recovers to 50%-70%, and the coal-fired power unit load returns to the baseline value.

[0029] This method uses DCS as the core of coal-fired power unit load regulation, superimposed with electrode boiler power to achieve joint response of "unit + electrode boiler", uses EMS as the core of energy storage dispatch, and achieves coordinated regulation of "energy storage and the former two" through data difference calculation. PMU is the core of data aggregation and feedback to ensure that the grid side obtains accurate actual power data and completes closed-loop control of AGC mode. Through the linkage of DCS+EMS+PMU, it solves the problem that independent systems of energy storage frequency regulation and electrode boiler cannot directly participate in AGC mode, realizes joint regulation of coal-fired power units, energy storage frequency regulation, and electrode boiler, and ensures that the actual power accurately responds to grid commands.

[0030] In an optional embodiment, the coal-fired power unit is connected to 280 t / h of industrial steam supply. The minimum load without the combined electrode boiler is 185 MW, and the minimum load with the combined electrode boiler is 105 MW (165 MW coal-fired power unit / 60 MW electrode boiler). The electrode boiler power setpoint P is set. e When ensuring industrial steam supply, priority should be given to reducing the load of coal-fired power units, with electrode boilers serving as a supplement, and following dispatch instructions. The advantage of frequency-regulating units in temporarily limiting the load of coal-fired power units should be fully utilized, and frequency regulation instructions from the power grid should be promptly restricted when adjusting the load of electrode boilers or starting and stopping them. Electrode boilers should be shut down promptly when the electricity price is higher than the equilibrium point, and the lower limit of coal-fired power unit load should be limited when the given power cannot meet the industrial steam supply. Electrode boilers should be kept running continuously during negative electricity prices, with load distribution as shown in the table below. During low electricity prices, the output of coal-fired power units should not exceed 200MW as much as possible.

[0031] Table 1. Load Ratio After Electrode Boiler Start-up AGC Power (MW) Coal-fired Power Unit Load (MW) Electrode Boiler (MW) 185 1850 180 1800 175 195 20 170 190 20 165 185 20 160 180 20 155 175 20 150 190 40 145 185 40 140 180 40 135 175 40 130 170 40 125 185 60 120 180 60 115 175 60 110 170 60 105 165 60 The table in Table 1 sets three load variation points for the electrode boiler: 20, 40, and 60, to minimize frequent load adjustments and avoid impacting frequency regulation performance. Adjustments and allocations are made dynamically based on load fluctuations. Using this method, the electrode boiler power is dynamically adjusted to create space for energy storage charging and discharging, preventing frequency regulation interruptions caused by battery over-charge limits, extending the cycle life of the energy storage battery, and reducing operating costs.

[0032] This invention also provides a frequency regulation system for deep peak shaving of coal-fired power units, including a coal-fired power unit, an electrode boiler subsystem, an electrochemical energy storage subsystem, and a collaborative control subsystem. By using the electrode boiler to convert electrical energy into thermal energy, the coal-fired power unit can continuously meet the frequency regulation requirements of the power grid under deep peak shaving conditions. Furthermore, by utilizing the electrochemical energy storage subsystem and the collaborative control subsystem, the system can meet the auxiliary frequency regulation service requirements of the power grid under deep peak shaving conditions of cogeneration units, even under the constraints of thermoelectric coupling contradictions.

[0033] In this embodiment, the coal-fired power unit adopts a 350MW supercritical cogeneration unit. Its power generation output end is connected to the power grid, and its heating end is connected to the industrial steam supply header. The coal-fired power unit is equipped with a coal-fired power unit DCS (Distributed Control System) for its own load regulation and operation status monitoring.

[0034] The power input terminal of the electrode boiler subsystem is connected to the plant power system of the coal-fired power unit, and the heat output terminal of the electrode boiler subsystem is connected to the industrial steam supply main pipe to convert electrical energy into heat energy. The electrode boiler subsystem is equipped with an electrode boiler control system. Specifically, the electrode boiler subsystem is used to convert electrical energy into industrial steam for external supply, realize the decoupling of heat and electricity, release the peak-shaving capacity of the coal-fired power unit, and, in conjunction with the electrode boiler, further realize the deep peak-shaving or even zero output of the coal-fired power unit.

[0035] Specifically, the electrode boiler subsystem adopts a 66MW electrode boiler (60MW electrode boiler + 6MW superheater), a 160MVA split on-load tap changer transformer and thermal pipelines. The power supply is taken from the 220kV step-up substation bus of the coal-fired power unit and stepped down to 10kV by the transformer. The 220℃, 1.6MPa steam generated by the thermal system is directly connected to the industrial steam supply bus, realizing thermoelectric decoupling and converting electrical energy into thermal energy. The collaborative control subsystem controls the stepless power regulation by adjusting the liquid level in the inner cylinder.

[0036] In other embodiments, a thermal storage electrode boiler of the same power can be used instead, with thermal energy buffering achieved through a thermal storage tank. Although the response speed is slightly slower, completing the 0-100% power switching within 30 minutes, it can further reduce the energy storage charging and discharging frequency, making it suitable for scenarios with slightly lower requirements for peak shaving response speed.

[0037] An electrochemical energy storage subsystem is provided, which includes an energy storage converter and an energy storage EMS (energy storage control system). The electrochemical energy storage subsystem is connected to the plant power system of the coal-fired power unit through the energy storage converter. Specifically, a 9MW / 4.5MWh lithium battery energy storage system is adopted. The DC side is connected to the 10kV distribution bus through the energy storage converter, and the AC side shares the 10kV power supply network with the electrode boiler subsystem. It has millisecond-level charge and discharge response capability and a rated charge and discharge power of 9MW.

[0038] In one embodiment, as shown in Figure 2, the electrochemical energy storage subsystem is mainly controlled by the EMS (Energy Management System), and communicates with the upstream RTU (Remote Terminal Unit) and DCS respectively. It adopts a communication link configuration of "optical cable + switch + network cable", Ethernet communication, uses the 104 protocol, and the interface is a network port. It communicates with the downstream BMS (Battery Management System) and energy storage converter using Modbus, and the interface is a network port.

[0039] In other embodiments, flywheel energy storage systems can be used instead of lithium battery energy storage, which have a faster response speed (≤10ms) and a longer cycle life, but have a higher cost per unit capacity. They are suitable for power grid scenarios with extremely high requirements for frequency regulation response speed.

[0040] The collaborative control subsystem communicates with the DCS of the coal-fired power unit, the control system of the electrode boiler, and the energy storage EMS to exchange data and achieve unified control.

[0041] The coordinated control subsystem also includes a data acquisition module, a load allocation module, an instruction execution module, and a status monitoring module. The data acquisition module is used to acquire real-time operating status data of the coal-fired power unit, electrode boiler subsystem, and electrochemical energy storage subsystem, and to receive grid dispatch instructions. The load allocation module is used to generate power allocation instructions for each subsystem based on the grid dispatch instructions and the operating status of each subsystem. Specifically, the load allocation module can introduce AI algorithms (such as LSTM neural networks) to train the model through historical operating data, thereby achieving predictive allocation of power instructions and further improving regulation accuracy and economy.

[0042] The instruction execution module is used to send the power allocation instructions to the coal-fired power unit, the electrochemical energy storage subsystem, and the electrode boiler subsystem respectively, so as to realize the coordinated response of the three. The status monitoring module is used to monitor the overall operational safety of the system. The status monitoring module is configured to monitor the state of charge of the electrochemical energy storage subsystem, and when the state of charge exceeds the preset range, trigger the load allocation module to adjust the power instructions of the electrode boiler subsystem, so as to indirectly manage the state of charge of the electrochemical energy storage subsystem.

[0043] Example 2 differs from Example 1 in that a frequency regulation system for deep peak shaving of coal-fired power units is applied in deep peak shaving mode. When the power grid issues a deep peak shaving command, the power of the electrode boiler is adjusted first. This is implemented through the following steps: the current power generation, heating power, electrode boiler power, and energy storage SOC of the coal-fired power unit are acquired in real time through the data acquisition module; the load allocation module calculates the amount of power generation load that the coal-fired power unit needs to reduce and prioritizes the allocation of the power generation load to the electrode boiler, controlling its power to increase from the base value to P1, where P1≤60MW; if the electrode boiler has reached its maximum power and still cannot meet the peak shaving demand, the power generation load of the coal-fired power unit is further reduced to 30% of the rated load, where the rated load is 105MW, to ensure that peak shaving is achieved. At this time, the electrochemical energy storage subsystem is in hot standby mode, and the SOC is maintained at 50%-70%.

[0044] Example 3: This example uses a 300MW cogeneration coal-fired power unit equipped with a 60MW electrode boiler and a 9MW energy storage system to perform grid frequency regulation under deep peak shaving conditions.

[0045] Prepare for system startup. The electrode boiler maintains a 20MW thermal standby power. The energy storage system is charged to SOC=60%. After the communication system passes the self-test, it receives the frequency modulation command.

[0046] Receive and parse the frequency modulation command to obtain the power grid AGC command: P=135MW; determine the electrode boiler power P. e When P = 135MW, which falls within the interval 130 ≤ P ≤ 150, determine P. e =40MW, P e =40MW is transmitted to electrode boilers, coal-fired power unit DCS and energy storage EMS.

[0047] Calculate the setpoint of the coal-fired power unit: Setpoint of coal-fired power unit = P + P e = 135 + 40 = 175MW; The DCS sets the power of the coal-fired power unit to 175MW, and the coal-fired power unit is adjusted at a rate of ≤2% / min.

[0048] Calculate energy storage demand, actual output P of coal-fired power units unit =173MW, with a deviation of -2MW: ΔP = P - (P unit - Pe) = 135 - (173 - 40) = 2MW; ΔP = 2MW > 0, energy storage discharge is required, EMS sets energy storage output P fm =2MW, energy storage responds within 30ms and begins discharging.

[0049] Calculate the actual grid power P actual = P unit- P e + P fm = 173 - 40 + 2 = 135MW. The actual grid-connected power is equal to the grid demand power. The PMU feeds back the 135MW actual grid-connected power to the grid.

[0050] Status optimization and continuous monitoring: Energy storage SOC=58%, electrode boiler power=40MW, coal-fired power unit power=173MW; all parameters are normal, maintain the current control strategy.

[0051] Two hours later, the energy storage SOC dropped to 28%, triggering over-limit protection and gradually adjusting: current P fm =3MW, P fm The linear reduction from 3MW to 0.5MW was simultaneously increased by 2.5MW for the coal-fired power unit. After adjustment, P... fm =0.5MW, the set value of coal-fired power units increased from 175MW to 177.5MW, while the actual grid-connected power remained at 135MW.

[0052] After the system shuts down and the grid frequency regulation command ends, the electrode boiler power drops to 20MW to maintain hot standby, the energy storage system is charged to SOC=60%, and the coal-fired power unit load recovers to the base value of 150MW.

[0053] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. This application is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of this application is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of this application should be considered to fall within the protection scope of this application.

Claims

1. A frequency regulation method for deep peak shaving in coal-fired power units, characterized in that, The process includes the following steps: Command reception: When the coal-fired power unit is in peak-shaving mode, obtain the grid frequency regulation command, which includes the AGC power command, and the AGC power command includes the total power P; Load response: Determine the setpoint for the electrode boiler regulation power and the setpoint for the coal-fired power unit, and send them to the corresponding execution systems respectively. Determine the energy storage output frequency regulation power based on the actual execution power of the execution systems; State optimization: Monitor the operating parameters of each execution system in real time. When the energy storage SOC is less than 30% or greater than 90%, adjust the power of the coal-fired power unit. The final actual power is calculated by the PMU and fed back to the grid, completing the regulation closed loop.

2. The frequency regulation method for deep peak shaving of coal-fired power units according to claim 1, characterized in that, The specific steps of load response are as follows: setting the electrode boiler regulating power setpoint P according to the AGC power command. e When 105MW≦P≦125MW, P e The capacity is 60MW; when 125MW < P < 130MW, P e The capacity is 50MW; when 130MW≦P≦150MW, P e The capacity is 40MW; when 150MW < P < 155MW, P e The capacity is 30MW; when 155MW≦P≦175MW, P e The capacity is 20MW; when 175MW < P < 180MW, P e The value is 10MW; when 180MW≤P≤185MW, P e The value is 0MW; the determined P e The value is sent to the electrode boiler control system, the coal-fired power unit DCS, and the energy storage EMS; the coal-fired power unit DCS receives the grid AGC command and adds the total power P to P. e The power setpoint of the coal-fired power unit is then generated, driving the coal-fired power unit to output the actual power P. unit ;Based on P by energy storage EMS unit P e In conjunction with the AGC command, calculate the energy storage frequency regulation action amount ΔP, and use ΔP as the energy storage output frequency regulation power P. fm △P is calculated using the following formula: △P = P - (P unit - P e When ΔP is positive, energy storage discharge occurs; when ΔP is negative, energy storage charging occurs.

3. The frequency regulation method for deep peak shaving of coal-fired power units according to claim 2, characterized in that, The final actual power of the PMU is P actual P is calculated using the following formula. actual = P unit - P e +P fm ;where P unit To drive the coal-fired power unit to output actual power, P fm For energy storage output frequency modulation power, P e The power setting value for the electrode boiler.

4. The frequency regulation method for deep peak shaving of coal-fired power units according to claim 1, characterized in that, The power setpoint of the coal-fired power unit is maintained in the range of 105MW-195MW, only handling slow power changes with a change rate of ≤2% / min; the power setpoint of the electrode boiler is dynamically adjusted according to the total power P, handling medium-speed power changes with a change rate of ≤5% / min, and the adjustment range is 0MW-60MW; the frequency regulation power output of the energy storage unit responds to high-frequency, small-amplitude power fluctuations with a response time of ≤50ms, and the adjustment range is -9MW to +9MW, ensuring that the frequency regulation command tracking accuracy reaches ±2MW.

5. The frequency regulation method for deep peak shaving of coal-fired power units according to claim 1, characterized in that, Before receiving the grid frequency regulation command, the system is started up to put the electrode boiler into hot standby mode, the energy storage SOC is adjusted to 50%-70%, and then a communication self-test is performed.

6. The frequency regulation method for deep peak shaving of coal-fired power units according to claim 1, characterized in that, In the state optimization step, the specific steps for adjusting the power of the coal-fired power unit are as follows: when the energy storage SOC is less than 30% or greater than 90%, gradually reduce the energy storage output frequency regulation power P. fm Until it drops to 0; synchronously adjust the power setpoint of the coal-fired power unit, increasing the amount by P. fm The reduction amount; continuous monitoring of SOC, when SOC recovers to the range of 30%-70%, gradually restore the energy storage frequency regulation function; after state optimization, the system is shut down, after the grid command ends, the electrode boiler is reduced to the minimum power to maintain hot standby, the energy storage SOC recovers to 50%-70%, and the coal-fired power unit load recovers to the base value.

7. A frequency regulation system for deep peak shaving in coal-fired power units, characterized in that, This includes coal-fired power units, which are equipped with a coal-fired power unit DCS for regulating their own power and monitoring their operating status. The system includes an electrode boiler subsystem, which is configured to convert electrical energy into thermal energy, and includes an electrode boiler and an electrode boiler control system; an electrochemical energy storage subsystem, which includes an energy storage converter and an energy storage EMS; and a collaborative control subsystem, which is communicatively connected to the coal-fired power unit DCS, the electrode boiler control system, and the energy storage EMS for data exchange and unified control.

8. The frequency regulation system for deep peak shaving of coal-fired power units according to claim 7, characterized in that, The collaborative control subsystem includes a data acquisition module, which is used to acquire real-time operating status data of the coal-fired power unit, electrode boiler subsystem and electrochemical energy storage subsystem, and receive grid dispatch instructions. The load allocation module is used to generate power allocation instructions for each subsystem based on the power grid dispatch instructions and the operating status of each subsystem. The instruction execution module is used to send the power allocation instructions to the coal-fired power unit, the electrochemical energy storage subsystem, and the electrode boiler subsystem, respectively; the status monitoring module is used to monitor the overall operational safety of the system.

9. The frequency regulation system for deep peak shaving of coal-fired power units according to claim 8, characterized in that, The status monitoring module is configured to monitor the power status of the electrochemical energy storage subsystem and, when the power status exceeds a preset range, trigger the load distribution module to adjust the power command of the electrode boiler subsystem in order to indirectly manage the state of charge of the electrochemical energy storage subsystem.

10. The frequency regulation system for deep peak shaving of coal-fired power units according to claim 7, characterized in that, The power generation output terminal of the coal-fired power unit is connected to the power grid, and the heating terminal is connected to the industrial steam supply main pipe. The electrode boiler subsystem also includes a transformer that supplies power to the electrode boiler. The power input terminal of the electrode boiler subsystem is connected to the plant power system of the coal-fired power unit, and the heat output terminal of the electrode boiler subsystem is connected to the industrial steam supply main pipe to convert electrical energy into heat energy.

Images