Energy storage device, control system and control method for improving AGC frequency modulation performance of power plant

Abstract

The present invention discloses an energy storage device, control system and control method for improving the AGC frequency modulation performance of a power plant. The energy storage device includes several energy storage subsystems, each of which includes a PCS container and a lithium iron phosphate battery system container; the PCS container includes a transformer connected to the high-voltage bus of the power grid and a bidirectional PCS connected to the transformer, and the lithium iron phosphate battery system container includes a battery system connected to the bidirectional PCS; the transformer is used to boost the three-phase AC output of the bidirectional PCS to the high-voltage bus voltage for the power plant when the energy storage subsystem is discharged, or to step down the high-voltage bus voltage of the power grid to the input voltage of the bidirectional PCS when the energy storage subsystem is charged; the battery system is used to store or discharge electric energy through the bidirectional PCS. The energy storage device and control system provided by the present invention can improve the AGC frequency modulation performance of the unit, and the energy storage device of the present invention can extend the life of the energy storage frequency modulation battery and improve the safety of the energy storage frequency modulation system.

Description

Technical Field

[0001] The present invention belongs to the technical field of AGC frequency modulation performance of power plants, and in particular relates to an energy storage device, a control system and a control method for improving the AGC frequency modulation performance of power plants. Background Art

[0002] The most important quality indicators in the power grid are: frequency and voltage. For the power grid, the frequency indicator is shared by the entire network. The stability of the frequency is achieved by the dynamic balance of power load and power generation. This is mainly achieved by the system dispatcher issuing dispatch instructions according to the changes in the power grid frequency at every moment, and constantly adjusting the power of the generators in the power grid. The change in system frequency directly reflects the balance of power supply and demand. When the power generation is greater than the load consumption, the system frequency increases, and when the load consumption is greater than the power generation, the frequency decreases. Therefore, the power grid dispatcher must constantly issue frequency regulation commands to the power plant to ensure that the frequency is within the qualified range. With the large number of new energy generators connected to the power grid and the increase in impact loads, in order to ensure the safe and economical operation of the power grid and improve the power quality of users, the power grid has higher and higher requirements for the frequency regulation of the units.

[0003] The production process and control process of thermal power units are complex. There are large delays in the energy generation and conversion process. In addition, the operating conditions and coal types often deviate from the design requirements, which greatly affects the response speed and control accuracy of the unit. Therefore, the problem that the unit's primary frequency regulation and AGC functions cannot meet the technical index requirements is more prominent.

[0004] Battery energy storage systems have the characteristics of fast response and precise tracking, making them more efficient than traditional frequency regulation methods. In recent years, the use of large-scale battery energy storage systems to replace power plants for frequency regulation has attracted attention from the industry. Compared with traditional power sources, energy storage has obvious technical advantages in providing frequency regulation for power grids, and its economic benefits will gradually emerge, which can effectively improve the operating efficiency of the power system.

[0005] During the operation of the existing AGC energy storage and frequency regulation project, a fire accident occurred in the energy storage battery. Due to improper control methods, the energy storage battery life was short (the battery was replaced in less than a year), and the actual frequency regulation effect was not ideal. Summary of the invention

[0006] The purpose of the present invention is to improve the AGC frequency regulation performance of a power plant, and to provide an energy storage device.

[0007] The present invention first provides an energy storage device for improving the AGC frequency modulation performance of a power plant, comprising a plurality of energy storage subsystems, each of which comprises a PCS container and a lithium iron phosphate battery system container; the PCS container comprises a transformer connected to a high-voltage busbar of a power grid and a bidirectional PCS connected to the transformer, and the lithium iron phosphate battery system container comprises a battery system connected to the bidirectional PCS; the transformer is used to boost the three-phase alternating current output by the bidirectional PCS to a high-voltage busbar voltage for a power plant when the energy storage subsystem is discharged, or to step down the high-voltage busbar voltage of the power grid to an input voltage of the bidirectional PCS when the energy storage subsystem is charged; and the battery system is used to store or discharge electric energy through the bidirectional PCS.

[0008] Preferably, the lithium iron phosphate battery system container also includes a BMS system, which is connected to the battery system and is used to monitor the battery system and issue an alarm when a failure occurs in the battery system.

[0009] Preferably, the lithium iron phosphate battery system container also includes an air conditioning system and a fire protection system; the air conditioning system is used to provide a good operating environment for the battery system, and the fire protection system includes a fire detection device and a gas fire extinguishing device. The fire detection device is used to automatically start the gas fire extinguishing device when a fire is detected in the lithium iron phosphate battery system container, and disconnect the external power supply of the container, and at the same time trigger the emergency stop disconnection of the energy storage subsystem and the high-voltage busbar of the power plant.

[0010] The present invention also provides a control system for improving the AGC frequency modulation performance of a power plant, comprising a power plant DCS system, a telecontrol device and a measurement and control device, and also comprising the energy storage device and an energy storage controller; the energy storage controller is connected to the energy storage subsystem of the energy storage device, the measurement and control device and the power plant DCS system, the measurement and control device is connected to the power plant DCS system, and the power plant DCS system is connected to the telecontrol device; the energy storage controller is used to process the received AGC command output and unit output to obtain the output value of the energy storage frequency modulation system and send the output value of the energy storage frequency modulation system to the bidirectional PCS and the measurement and control device; the bidirectional PCS is used to process the received energy storage frequency modulation system The output value is used to measure the energy storage output of the energy storage subsystem, and the energy storage controller is used to measure the energy storage output of the energy storage subsystem and send it to the measurement and control device; the measurement and control device is used to receive the energy storage output sent by the energy storage controller and merge it with the measured output of the thermal power unit as an output feedback signal and upload it to the power plant DCS system; the telecontrol device is used to collect data from the power plant DCS system and send the corresponding data to the power grid dispatching center through the remote channel after conversion and processing, and at the same time send the AGC command sent by the power grid dispatching center to the power plant DCS system; the power plant DCS system further feeds back the AGC command sent by the power grid dispatching center to the energy storage controller and the thermal power unit.

[0011] Preferably, the energy storage controller is a PLC controller.

[0012] Finally, the present invention provides a control method for the control system when the energy storage AGC outputs power, and the control method includes:

[0013] 1) Read the AGC status of the unit: The energy storage controller obtains the AGC frequency regulation status of the unit through the power plant DCS, and determines whether the thermal power unit is in the AGC state. If the thermal power unit is in the non-AGC state, it means that the power grid dispatching center does not need the unit to participate in the frequency regulation. At this time, the energy storage frequency regulation system charges and discharges the battery with 50% SOC as the target;

[0014] 2) Obtaining AGC output and unit output: If the unit is in the AGC frequency modulation state, the energy storage controller obtains the AGC command output value Pa and the unit current output value Pb through the power plant DCS, and calculates the energy storage output Pc = Pa-Pb;

[0015] 3) PLC determines charging and discharging: if Pc>0, the energy storage and frequency modulation system (i.e., the energy storage device) discharges; if Pc<0, the energy storage and frequency modulation system charges;

[0016] 4) Reading energy storage SOC: The energy storage controller reads the remaining capacity of the current battery system through the BMS system;

[0017] 5) Active discharge: When the remaining capacity of the battery is between 30% and 100%, the energy storage frequency modulation system outputs Pc. If Pc>9MW (maximum output power of the energy storage frequency modulation system), the output is 9MW;

[0018] 6) Conservative discharge: When the remaining battery capacity is between 20% and 30%, the energy storage frequency modulation system outputs Pc. If Pc>6MW, the output is 6MW.

[0019] 7) Passive discharge: When the remaining capacity of the battery is between 10% and 20%, the energy storage frequency modulation system outputs Pc. If Pc>4MW, it outputs 4MW.

[0020] 8) No discharge: When the remaining battery capacity is less than 10%, the energy storage frequency modulation system outputs Pc. If Pc>0.1MW, it outputs 0.1MW;

[0021] 9) Active charging: When the remaining battery capacity is between 0% and 70%, the energy storage frequency modulation system absorbs Pc. If Pc>9MW (maximum charging power of the energy storage frequency modulation system), it absorbs 9MW.

[0022] 10) Conservative charging: When the remaining battery capacity is between 70% and 85%, the energy storage frequency regulation system absorbs Pc. If Pc>6MW, it absorbs 6MW.

[0023] 11) Passive charging: When the remaining battery capacity is between 85% and 95%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, it absorbs 4MW.

[0024] 12) No charging: When the remaining battery capacity is greater than 95%, the energy storage frequency modulation system absorbs Pc. If Pc>0.1MW, it absorbs 0.1MW.

[0025] The present invention solves the problems of primary hardware design of energy storage AGC frequency modulation technology, secondary control system design, energy storage AGC output control method, and energy storage battery charging and discharging strategy.

[0026] The present invention is mainly applied to auxiliary services of power frequency regulation, and can significantly improve the AGC frequency regulation performance of power plants, including a stable and reliable hardware control system and an advanced and efficient control algorithm.

[0027] An energy storage device, control system and control method for improving the AGC frequency modulation performance of a power plant adopts a safer lithium iron phosphate battery as an energy storage frequency modulation battery, uses a highly stable PLC controller, and combines a BMS battery management system, a two-way PCS device, and auxiliary safety systems such as air conditioning and fire protection systems to form an energy storage frequency modulation control system. A control method with four levels of response, namely "active", "conservative", "passive" and "non-responsive", is used to solve the life problem of energy storage frequency modulation batteries while ensuring the benefits.

[0028] The technical solution adopted by the present invention is:

[0029] The primary hardware solution includes: lithium iron phosphate battery system container and PCS container.

[0030] The lithium iron phosphate battery system container includes a battery system, an air conditioning system, a fire protection system, and a BMS system. The BMS system is mainly responsible for monitoring the battery system, including single cell voltage, total current, battery temperature, insulation resistance, SOC, SOH, etc. When the battery has a single cell voltage that is too high, too low, overcurrent, overtemperature, etc., the BMS outputs an alarm signal. The air conditioning system is responsible for providing a good operating environment for the battery system to ensure the consistency of the battery cell life and state. The fire protection system protects the fire detection and gas fire extinguishing devices. When a fire occurs in the container, the fire extinguishing device will be automatically activated and the container will be disconnected from the external power supply. At the same time, the entire energy storage frequency modulation system will be triggered to stop and disconnect from the plant busbar to ensure that the overall safety of the system and the safety of the unit operation are not affected. The PCS container mainly includes a bidirectional PCS and a transformer. The bidirectional PCS is the core equipment in the energy storage subsystem. As the power interface device connecting the energy storage subsystem to the power grid, the bidirectional PCS is responsible for controlling the bidirectional flow of energy between the power grid and the energy storage unit, meeting the power control accuracy and the response speed requirements of fast charge and discharge conversion. When the energy storage system is discharged, the transformer boosts the three-phase AC power output by the PCS to the high-voltage bus voltage for plant use. When the energy storage subsystem is charged, the high-voltage bus voltage is reduced to the PCS input voltage.

[0031] Secondary control system: including energy storage controller, power plant measurement and control device, power plant DCS system, power plant telecontrol device. The energy storage controller uses PLC controller to replace the traditional industrial computer, and Siemens S7-1500-cpu-1513-1PN is selected. It has the advantages of long-term reliable operation, strong anti-interference, and convenient debugging. The telecontrol device is mainly used to collect real-time data from the operation site, and send it to the power grid dispatching center through the remote channel after corresponding data conversion and processing. At the same time, it accepts remote control and remote adjustment commands from the dispatching center to drive the on-site equipment to achieve the purpose of control and regulation. The unit distributed control system (DCS system) covers the monitoring and control functions of the primary and secondary equipment of the entire thermal power plant. The main function of the measurement and control device is to measure the output of the thermal power unit and the output of the energy storage system, and merge the outputs of the two and upload them to the power grid dispatching as an output feedback signal.

[0032] 1. The energy storage AGC output control method is as follows: Read the AGC status of the unit: The energy storage controller obtains the AGC frequency regulation status of the unit through the power plant DCS. The non-AGC status means that the power grid dispatching center does not need the unit to participate in frequency regulation. At this time, the energy storage frequency regulation system charges and discharges the battery with 50% SOC as the target.

[0033] 2. Obtain AGC output and unit output: If the unit is in the AGC frequency modulation state, the energy storage controller obtains the AGC command output value Pa and the unit current output value Pb through the power plant DCS, and calculates the energy storage output Pc = Pa-Pb.

[0034] 3.PLC determines charging and discharging: if Pc>0, the energy storage and frequency modulation system discharges; if Pc<0, the energy storage and frequency modulation system charges.

[0035] 4. Read the energy storage SOC: When the energy storage frequency modulation system is charging or discharging, the energy storage controller first reads the remaining capacity of the current battery system through the BMS system.

[0036] 5. Active discharge: When the remaining capacity of the battery is between 30% and 100%, the energy storage frequency modulation system outputs Pc. If Pc>9MW (maximum output power of the energy storage frequency modulation system), the output is 9MW.

[0037] 6. Conservative discharge: When the remaining capacity of the battery is between 20% and 30%, the energy storage frequency regulation system outputs Pc. If Pc>6MW, the output is 6MW.

[0038] 7. Passive discharge: When the remaining capacity of the battery is between 10% and 20%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, it outputs 4MW.

[0039] 8. No discharge: When the remaining battery capacity is less than 10%, the energy storage frequency modulation system outputs Pc. If Pc>0.1MW, it outputs 0.1MW.

[0040] 9. Active charging: When the remaining battery capacity is between 0% and 70%, the energy storage frequency modulation system absorbs Pc. If Pc>9MW (maximum charging power of the energy storage frequency modulation system), it absorbs 9MW.

[0041] 10. Conservative charging: When the remaining battery capacity is between 70% and 85%, the energy storage frequency regulation system absorbs Pc. If Pc>6MW, it absorbs 6MW.

[0042] 11. Passive charging: When the remaining capacity of the battery is between 85% and 95%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, it absorbs 4MW.

[0043] 12. No charging: When the remaining battery capacity is greater than 95%, the energy storage frequency modulation system absorbs Pc. If Pc>0.1MW, it absorbs 0.1MW.

[0044] Energy storage frequency regulation system regulation effect:

[0045] When the energy storage and frequency modulation system of the present invention is added to the frequency modulation, the regulation effect is as described in the following table: the second line in the following table shows the monthly average frequency modulation performance of the unit before the energy storage and frequency modulation system is added, and the third line shows the monthly average frequency modulation performance after the energy storage and frequency modulation system is added. It can be seen that the assessment indicators are significantly improved, and at the same time, the health status SOH of the energy storage and frequency modulation battery decays by less than 5% in a year.

[0046]

[0047] K1, K2, K3, and Kp are the main index parameters for the power grid to assess the AGC frequency regulation performance of the unit, among which K1 is the AGC regulation speed, K2 is the AGC regulation accuracy, K3 is the AGC response time, and Kp=K1*K2*K3 is the frequency regulation performance.

[0048] The core technical points of the present invention: the implementation method of energy storage frequency modulation and the system integration solution.

[0049] Energy storage AGC output control method; energy storage battery charging and discharging strategy.

[0050] Compared with the prior art, the beneficial effects of the present invention are: 1: The energy storage device and control system provided by the present invention can improve the AGC frequency modulation performance of the unit, and the energy storage device of the present invention can extend the life of the energy storage frequency modulation battery and improve the safety of the energy storage frequency modulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural schematic diagram of the control system of the present invention;

[0052] Figure 2 It is a flow chart of charging and discharging of the energy storage system of the present invention. DETAILED DESCRIPTION

[0053] An energy storage device for improving the AGC frequency modulation performance of a power plant includes two energy storage subsystems, each of which includes a PCS container 2 and a lithium iron phosphate battery system container 1 connected to the PCS container 2; the PCS container 2 includes a transformer 21 connected to the high-voltage bus of a thermal power unit and a bidirectional PCS 22 connected to the transformer 21. The lithium iron phosphate battery system container 1 includes a battery system 13 connected to the bidirectional PCS 22, and the lithium iron phosphate battery system container 1 also includes a BMS system 14, a fire protection system 11, and an air conditioning system 12. The transformer 21 is used to boost the three-phase AC output of the bidirectional PCS 22 to the high-voltage bus voltage for the power plant when the energy storage subsystem is discharged, or to step down the high-voltage bus voltage of the thermal power unit to the bidirectional PCS input voltage when the energy storage subsystem is charged; the battery system 13 is used to store or discharge electric energy through the bidirectional PCS 22. The BMS system 14 is connected to the battery system 13, and is used to monitor the battery system 13 and alarm when a fault occurs in the battery system.

[0054] The air conditioning system 12 is used to provide a good operating environment for the battery system 13. The fire protection system 11 includes a fire detection device and a gas fire extinguishing device. The fire detection device is used to automatically start the gas fire extinguishing device when a fire is detected in the lithium iron phosphate battery system container, and stop the container from supplying power to the outside.

[0055] The present invention also provides a control system for improving the AGC frequency modulation performance of a power plant, comprising a power plant DCS system 5, a telecontrol device 6, an energy storage controller 3 and a measurement and control device 4; the energy storage controller 3 is connected to the PCS container and the lithium iron phosphate battery system container of each energy storage subsystem, the energy storage controller 3 is also connected to the measurement and control device 4 and the power plant DCS system 5, and the power plant DCS system 5 is connected to the telecontrol device 6. The energy storage controller is used to receive the AGC command output and unit output sent by the power plant DCS system, and calculate the output value of the energy storage frequency modulation system according to the output of the two and the control algorithm, and send the output value of the energy storage frequency modulation system to the two-way PCS 22, and the two-way PCS 22 is used to perform energy storage output according to the received energy storage frequency modulation output value; at this time, the energy storage controller 3 measures the actual energy storage output of the energy storage subsystem and transmits the energy storage output to the measurement and control device 4, and the measurement and control device 4 is used to receive the energy storage output sent by the energy storage controller and merge it with the measured output of the thermal power unit and upload it to the power plant DCS system 5 as an output feedback signal, and the power plant DCS system 5 sends the output feedback signal to the telecontrol device; the telecontrol device collects the data of the power plant DCS and converts and processes the corresponding data and sends it to the power grid dispatching center through the remote channel, and at the same time sends the AGC command sent by the power grid dispatching center to the power plant DCS system; the power plant DCS system further sends and feeds back the AGC command sent by the power grid dispatching center to the energy storage controller and the thermal power unit. The energy storage controller uses a PLC controller. According to the above control system, the present invention also provides a control method of the control system;

[0056] like Figure 2 As shown;

[0057] Step 101: The energy storage controller reads the AGC status of the unit: The energy storage controller obtains the AGC frequency modulation status of the unit through the power plant DCS, and proceeds to step 102: determines whether the thermal power unit is in the AGC state;

[0058] Step 103: If the thermal power unit is in non-AGC state, it means that the power grid dispatching center does not need the unit to participate in frequency regulation. At this time, the energy storage frequency regulation system (ie, the energy storage device) charges and discharges the battery with 50% SOC as the target.

[0059] Step 104: If the thermal power unit is in the AGC state, obtain the AGC output and the unit output: the energy storage controller obtains the AGC command output value Pa and the unit current output value Pb through the power plant DCS, and calculates the energy storage output Pc=Pa-Pb.

[0060] Step 105: The energy storage controller determines charging and discharging: if Pc>0, the energy storage frequency modulation system discharges and proceeds to step 106; if Pc<0, the energy storage frequency modulation system charges and proceeds to step 107.

[0061] Step 106: When the energy storage frequency modulation system is discharged, the energy storage controller reads the remaining capacity of the current battery system through the BMS system;

[0062] Step 107: When the energy storage frequency modulation system is charging, the energy storage controller reads the remaining capacity of the current battery system through the BMS system;

[0063] Step 108: Active discharge: When the remaining capacity of the battery is between 30% and 100%, the energy storage frequency modulation system outputs Pc. If Pc>9MW (maximum output power of the energy storage frequency modulation system), the output is 9MW.

[0064] Step 109: Conservative discharge: When the remaining capacity of the battery is between 20% and 30%, the energy storage frequency regulation system outputs Pc. If Pc>6MW, the output is 6MW.

[0065] Step 110: Passive discharge: When the remaining capacity of the battery is between 10% and 20%, the energy storage frequency modulation system outputs Pc. If Pc>4MW, the output is 4MW.

[0066] Step 111: No discharge: When the remaining capacity of the battery is less than 10%, the energy storage frequency modulation system outputs Pc. If Pc>0.1MW, it outputs 0.1MW.

[0067] Step 112: Active charging: When the remaining capacity of the battery is between 0% and 70%, the energy storage frequency modulation system absorbs Pc. If Pc>9MW (maximum charging power of the energy storage frequency modulation system), 9MW is absorbed.

[0068] Step 113: Conservative charging: When the remaining capacity of the battery is between 70% and 85%, the energy storage frequency regulation system absorbs Pc. If Pc>6MW, 6MW is absorbed.

[0069] Step 114: Passive charging: When the remaining capacity of the battery is between 85% and 95%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, 4MW is absorbed.

[0070] Step 115: No charging: When the remaining battery capacity is greater than 95%, the energy storage frequency modulation system absorbs Pc. If Pc>0.1MW, it absorbs 0.1MW.

Claims

1. A control system for improving the AGC frequency modulation performance of a power plant, comprising a power plant DCS system, a telecontrol device and a measurement and control device, characterized in that: Also included is an energy storage device, an energy storage controller; The energy storage controller is connected to the energy storage subsystem, the measurement and control device and the power plant DCS system of the energy storage device, the measurement and control device is connected to the power plant DCS system, and the power plant DCS system is connected to the telecontrol device; the energy storage controller is used to process the received AGC command output and unit output to obtain the energy storage frequency modulation system output value and send the energy storage frequency modulation system output value to the two-way PCS; the two-way PCS is used to perform the energy storage output of the energy storage subsystem according to the received energy storage frequency modulation system output value, and the energy storage controller is used to measure the energy storage output of the energy storage subsystem and send it to the measurement and control device; the measurement and control device is used to receive the energy storage output sent by the energy storage controller and merge it with the measured thermal power unit output as an output feedback signal and upload it to the power plant DCS system; the telecontrol device is used to collect data from the power plant DCS system and send the corresponding data to the power grid dispatching center through the remote channel after conversion and processing, and at the same time send the AGC command sent by the power grid dispatching center to the power plant DCS system, and the power plant DCS system further feeds back the AGC command sent by the power grid dispatching center to the energy storage controller and the thermal power unit; The energy storage device includes a plurality of energy storage subsystems, each of which includes a PCS container and a lithium iron phosphate battery system container; the PCS container includes a transformer connected to the high-voltage bus of the power grid and a bidirectional PCS connected to the transformer, and the lithium iron phosphate battery system container includes a battery system connected to the bidirectional PCS; the transformer is used to boost the three-phase AC power output by the bidirectional PCS to the high-voltage bus voltage for the power plant when the energy storage subsystem is discharged, or to step down the high-voltage bus voltage of the power grid to the input voltage of the bidirectional PCS when the energy storage subsystem is charged; the battery system is used to store or discharge electric energy through the bidirectional PCS; The control method for improving the AGC frequency regulation performance of a power plant when the energy storage AGC is outputting power comprises the following steps: 1) Read the AGC status of the unit: The energy storage controller obtains the AGC frequency regulation status of the unit through the power plant DCS, and determines whether the thermal power unit is in the AGC state. If the thermal power unit is in the non-AGC state, it means that the power grid dispatching center does not need the unit to participate in the frequency regulation. At this time, the energy storage frequency regulation system charges and discharges the battery with 50% SOC as the target; 2) Obtaining AGC output and unit output: If the unit is in the AGC frequency modulation state, the energy storage controller obtains the AGC command output value Pa and the unit current output value Pb through the power plant DCS, and calculates the energy storage output Pc = Pa-Pb; 3) PLC determines charging and discharging: if Pc>0, the energy storage and frequency modulation system discharges; if Pc<0, the energy storage and frequency modulation system charges; 4) Reading energy storage SOC: The energy storage controller reads the remaining capacity of the current battery system through the BMS system; 5) Active discharge: When the remaining capacity of the battery is between 30% and 100%, the energy storage frequency regulation system outputs Pc. If Pc>9MW, it outputs 9MW.

2. The control system for improving the AGC frequency modulation performance of a power plant according to claim 1 is characterized in that: The energy storage controller is a PLC controller.

3. The control system for improving the AGC frequency modulation performance of a power plant according to claim 1 is characterized in that: The lithium iron phosphate battery system container also includes a BMS system, which is connected to the battery system and is used to monitor the battery system and issue an alarm when a failure occurs in the battery system.

4. The control system for improving the AGC frequency modulation performance of a power plant according to claim 3 is characterized in that: The lithium iron phosphate battery system container also includes an air conditioning system and a fire protection system; the air conditioning system is used to provide a good operating environment for the battery system, and the fire protection system includes a fire detection device and a gas fire extinguishing device. The fire detection device is used to automatically start the gas fire extinguishing device when a fire is detected in the lithium iron phosphate battery system container, and disconnect the external power supply of the container.

5. The control system for improving the AGC frequency modulation performance of a power plant according to claim 1, characterized in that: The control method of the control system when the energy storage AGC outputs power also includes the following specific steps: 6) Conservative discharge: When the remaining capacity of the battery is between 20% and 30%, the energy storage frequency modulation system outputs Pc. If Pc>6MW, the output is 6MW. 7) Passive discharge: When the remaining capacity of the battery is between 10% and 20%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, it outputs 4MW. 8) No discharge: When the remaining battery capacity is less than 10%, the energy storage frequency modulation system outputs Pc. If Pc>0.1MW, the output is 0.1MW. 9) Active charging: When the remaining battery capacity is between 0% and 70%, the energy storage frequency regulation system absorbs Pc. If Pc>9MW, it absorbs 9MW. 10) Conservative charging: When the remaining battery capacity is between 70% and 85%, the energy storage frequency regulation system absorbs Pc. If Pc>6MW, it absorbs 6MW. 11) Passive charging: When the remaining capacity of the battery is between 85% and 95%, the energy storage frequency regulation system outputs Pc. If Pc>4MW, it absorbs 4MW. 12) No charging: When the remaining capacity of the battery is greater than 95%, the energy storage frequency modulation system absorbs Pc. If Pc>0.1MW, it absorbs 0.1MW.

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