Combined frequency modulation method and system for hybrid energy storage and thermal power generating unit

Abstract

The invention belongs to the technical field of power systems, and discloses a combined frequency modulation method and system for hybrid energy storage and thermal power generating units, and the method comprises the steps: carrying out the optimization calculation of a target power instruction of each energy storage converter through an SOC balanced distribution algorithm; determining a primary frequency modulation control strategy or an automatic power generation control strategy according to the frequency modulation control event and the priority; and based on the determined control strategy, controlling the hybrid energy storage system to quickly respond to a scheduling power instruction in combination with the corresponding target power instruction, and completing combined frequency modulation of the hybrid energy storage system and the thermal power generating unit. According to the method, the AGC adjusting performance index can reach the best, the main steam pressure fluctuation range is reduced, the unit economical efficiency is improved, different cooperation strategies of the super capacitor and the lithium battery can be designed, a thermal power unit locking scheme is designed to reduce unit abrasion, the AGC adjusting performance is further improved, and in addition, the method is suitable for popularization and application. A primary frequency modulation control strategy is further designed, and primary frequency modulation is divided into four stages.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a combined frequency regulation method and system for hybrid energy storage and thermal power generation units. Background Art

[0002] With the continuous development of new power systems with new energy as the main body, the power grid and power supply structure have undergone significant changes, and the power system's demand for frequency regulation resources has become more urgent. At present, the domestic frequency regulation power supply is mainly thermal power units, which generally have problems such as long response time, poor regulation accuracy, and reverse regulation during the frequency regulation process, making it difficult to meet the power grid frequency regulation needs. At the same time, the frequent increase and decrease of loads by thermal power units in the process of participating in frequency regulation will aggravate the fatigue and wear of the equipment. Both lithium batteries and supercapacitors have the advantages of fast response speed, strong short-term power throughput, and flexible regulation, and can achieve full power output in milliseconds. Using lithium batteries and supercapacitor energy storage systems to assist thermal power units in participating in frequency regulation can effectively improve the frequency regulation capability of the units, alleviate the pressure of power grid frequency regulation assessment, and reduce the fatigue and wear of the units themselves. In engineering applications, compared with supercapacitors, lithium batteries are low in price but short in life. Lithium batteries need to be replaced in three to five years for the frequency regulation project of thermal power units assisted by lithium batteries. Supercapacitors have a long life but high price and low energy density. The cycle life of supercapacitors is dozens of times that of lithium batteries. Taking into account the advantages and disadvantages of lithium batteries and supercapacitors, a combination of the two can take into account both economy and lifespan.

[0003] At present, there are relatively few engineering cases in China that use hybrid energy storage systems of lithium batteries and supercapacitors to assist thermal power units in frequency regulation. The existing thermal storage combined frequency regulation control strategy is to couple thermal power and energy storage only on the electrical side, with thermal power units regulating at a fixed rate, and energy storage compensating for the insufficient regulation, and thermal power and energy storage control not interfering with each other. This control strategy is easy to implement and is helpful in improving the regulation performance of thermal power units, but the control strategy is not designed for the regulation characteristics of thermal power units and combined energy storage, the regulation advantages of energy storage are not fully utilized to reduce thermal power wear, and the deep coupling between thermal power and energy storage is not achieved.

[0004] Therefore, how to provide a combined frequency regulation method and system for hybrid energy storage and thermal power units is a problem that needs to be solved urgently. Summary of the invention

[0005] The embodiment of the present invention provides a combined frequency regulation method and system of a hybrid energy storage and a thermal power unit to solve the above-mentioned technical problems in the prior art.

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended to be a general review, nor is it intended to identify key / important components or to delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0007] According to a first aspect of an embodiment of the present invention, a method for combined frequency regulation of a hybrid energy storage and a thermal power unit is provided.

[0008] In one embodiment, the combined frequency regulation method of hybrid energy storage and thermal power generation units includes:

[0009] Based on the hybrid energy storage system configured with supercapacitors and lithium batteries, the target power command of each energy storage converter is optimized and calculated through the SOC balanced distribution algorithm;

[0010] Set the priority of primary frequency regulation control and automatic generation control, and determine the primary frequency regulation control strategy or automatic generation control strategy according to the frequency regulation control events and priorities;

[0011] Based on the determined control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0012] In one embodiment, during discharge, the target power command is calculated as follows:

[0013]

[0014] When charging, the target power command is calculated as follows:

[0015]

[0016] In the formula, represents the active power instruction of the i-th energy storage converter;

[0017] represents the remaining power of the i-th energy storage converter;

[0018] n represents the number of energy storage converters;

[0019] P cmd Indicates the total active power command of all energy storage converters in the whole station.

[0020] In one embodiment, setting the priority of primary frequency regulation control and automatic power generation control, and determining the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority includes:

[0021] When the thermal power unit is in the automatic power generation control mode, the hybrid energy storage system executes the automatic power generation control strategy;

[0022] When the grid frequency changes or the thermal power unit receives a simulated disturbance signal from the provincial dispatcher, the hybrid energy storage system executes a frequency regulation control strategy;

[0023] When the primary frequency regulation control conflicts with the automatic generation control, the hybrid energy storage system is set to give priority to the primary frequency regulation control strategy.

[0024] In one embodiment, based on the automatic power generation control strategy, the hybrid energy storage system is controlled to quickly respond to the dispatching power command in combination with the corresponding target power command to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit, including:

[0025] Process automatic power generation control instructions based on rate limits to generate total target values ​​for thermal power unit load instructions and thermal-storage combined frequency regulation instructions;

[0026] According to the automatic power generation control evaluation index, the total target value of the thermal power generation combined frequency regulation command is divided into a response time period, a regulation rate period and a regulation accuracy period, and the thermal power unit locking command is triggered in the waiting area of ​​the regulation accuracy period;

[0027] Based on the deviation between the main steam pressure value controlled by the boiler and the main steam pressure set value, dynamically adjust the load command change rate of the thermal power unit;

[0028] Determine the coordination strategy between supercapacitors and lithium batteries according to the regulation requirements of the response time period, regulation rate section, and regulation accuracy section;

[0029] Combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, completing the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0030] In one embodiment, the automatic power generation control instruction is processed by rate limiting to generate the total target value of the thermal power unit load instruction and the thermal power generation combined frequency regulation instruction, including:

[0031] The automatic power generation control instruction is processed by using the speed limit based on the control of the thermal power unit to generate the load instruction of the thermal power unit;

[0032] The automatic power generation control command is processed by using the speed limit based on the hybrid energy storage system control to generate the total target value of the thermal-storage joint frequency regulation command;

[0033] Among them, within the response time period, the speed limit calculation formula based on the hybrid energy storage system control is:

[0034]

[0035] In the regulation rate section, the speed limit calculation formula based on the hybrid energy storage system control is:

[0036]

[0037] In the formula, v n Indicates the standard regulation rate.

[0038] In one embodiment, the automatic power generation control evaluation index includes a regulation rate index, a regulation accuracy index and a response time index.

[0039] In one embodiment, the coordination strategy between the supercapacitor and the lithium battery is determined according to the regulation requirements of the response time period, the regulation rate section, and the regulation accuracy section, including:

[0040] In the response time period, the supercapacitor takes priority. When the remaining power of the supercapacitor reaches the limit value, the lithium battery is used for supplementary adjustment.

[0041] In the adjustment speed section, the lithium battery takes priority. When the remaining power of the lithium battery reaches the limit value, the supercapacitor will make additional adjustments.

[0042] In the adjustment accuracy section, the lithium battery is used for adjustment first, and when it reaches the waiting area, the supercapacitor is used for adjustment, and the insufficient adjustment part is supplemented by the lithium battery.

[0043] In one embodiment, based on the primary frequency regulation control strategy, the hybrid energy storage system is controlled to quickly respond to the dispatching power command in combination with the corresponding target power command to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit, including:

[0044] In the first stage, when the grid frequency deviation exceeds the primary frequency regulation dead zone, the thermal energy storage combined frequency regulation system determines it as a primary frequency regulation action and records the current total actual power of the thermal energy storage and the actual power of the hybrid energy storage system. When the grid frequency deviation exceeds 0.1Hz, the hybrid energy storage system participates in the primary frequency regulation.

[0045] In the second stage, the hybrid energy storage system participates in the primary frequency regulation according to the energy storage power command, where the energy storage power command = the total actual active power of the thermal power plant at the start of the primary frequency regulation + the primary frequency regulation command - the actual power of the thermal power unit.

[0046] In the third stage, when the grid frequency deviation is less than 0.05Hz, the hybrid energy storage system exits the primary frequency regulation, and the energy storage power command remains unchanged;

[0047] In the fourth stage, when the grid frequency deviation is less than the dead zone of the primary frequency regulation action, the thermal-storage combined frequency regulation system determines that the primary frequency regulation action is completed, and the hybrid energy storage system exits the primary frequency regulation action.

[0048] According to a second aspect of an embodiment of the present invention, a combined frequency regulation system of a hybrid energy storage and a thermal power unit is provided.

[0049] In one embodiment, the combined frequency regulation system of the hybrid energy storage and thermal power generation unit includes:

[0050] The power command calculation module is used to configure a hybrid energy storage system based on supercapacitors and lithium batteries, and optimize the calculation of the target power command of each energy storage converter through the SOC balanced distribution algorithm;

[0051] A control strategy determination module is used to set the priority of primary frequency regulation control and automatic power generation control, and determine the primary frequency regulation control strategy or automatic power generation control strategy according to the frequency regulation control event and priority;

[0052] The joint frequency regulation module is used to control the hybrid energy storage system to quickly respond to the dispatching power command based on the determined control strategy and the corresponding target power command, so as to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0053] In one embodiment, during discharge, the target power command is calculated as follows:

[0054]

[0055] When charging, the target power command is calculated as follows:

[0056]

[0057] In the formula, represents the active power instruction of the i-th energy storage converter;

[0058] represents the remaining power of the i-th energy storage converter;

[0059] n represents the number of energy storage converters;

[0060] P cmd Indicates the total active power command of all energy storage converters in the whole station.

[0061] In one embodiment, the control strategy determination module sets the priority of primary frequency regulation control and automatic power generation control, and determines the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation event and the priority. When the thermal power unit is in the automatic power generation control mode, the hybrid energy storage system executes the automatic power generation control strategy; when the grid frequency changes or the thermal power unit receives a simulated disturbance signal issued by the provincial dispatcher, the hybrid energy storage system executes the primary frequency regulation control strategy; when the primary frequency regulation control conflicts with the automatic power generation control, the hybrid energy storage system is set to give priority to the primary frequency regulation control strategy.

[0062] In one embodiment, the joint frequency regulation module controls the hybrid energy storage system to quickly respond to the dispatching power instruction based on the automatic power generation control strategy and in combination with the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit. Based on the rate limit, the automatic power generation control instruction is processed to generate the load instruction of the thermal power unit and the total target value of the fire-storage joint frequency regulation instruction; the total target value of the fire-storage joint frequency regulation instruction is divided into a response time period, an adjustment rate section and an adjustment accuracy section according to the automatic power generation control evaluation index, and the thermal power unit locking instruction is triggered in the waiting area of ​​the adjustment accuracy section; based on the deviation between the main steam pressure value of the boiler control and the main steam pressure setting value, the load instruction change rate of the thermal power unit is dynamically adjusted; the coordination strategy between the supercapacitor and the lithium battery is determined according to the regulation requirements of the response time period, the adjustment rate section and the adjustment accuracy section; the hybrid energy storage system is controlled to quickly respond to the dispatching power instruction in combination with the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0063] In one embodiment, when the joint frequency regulation module processes the automatic power generation control instruction through rate limiting to generate the load instruction of the thermal power unit and the total target value of the thermal energy storage joint frequency regulation instruction, the automatic power generation control instruction is processed by the speed limit based on the control of the thermal power unit to generate the load instruction of the thermal power unit; the automatic power generation control instruction is processed by the speed limit based on the control of the hybrid energy storage system to generate the total target value of the thermal energy storage joint frequency regulation instruction;

[0064] Among them, within the response time period, the speed limit calculation formula based on the hybrid energy storage system control is:

[0065]

[0066] In the regulation rate section, the speed limit calculation formula based on the hybrid energy storage system control is:

[0067]

[0068] In the formula, v n Indicates the standard regulation rate.

[0069] In one embodiment, the automatic power generation control evaluation index includes a regulation rate index, a regulation accuracy index and a response time index.

[0070] In one embodiment, when the joint frequency modulation module determines the coordination strategy between the supercapacitor and the lithium battery according to the regulation requirements of the response time period, the regulation rate section, and the regulation accuracy section, in the response time period, the supercapacitor participates first, and when the remaining power of the supercapacitor reaches the limit value, the lithium battery supplements the regulation; in the regulation rate section, the lithium battery participates first, and when the remaining power of the lithium battery reaches the limit value, the supercapacitor supplements the regulation; in the regulation accuracy section, the lithium battery participates in the regulation first, and when it reaches the waiting area, the supercapacitor participates in the regulation, and the insufficient regulation is supplemented by the lithium battery.

[0071] In one embodiment, the joint frequency regulation module controls the hybrid energy storage system to quickly respond to the dispatching power instruction based on the primary frequency regulation control strategy and in combination with the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit. In the first stage, when the grid frequency deviation exceeds the primary frequency regulation action dead zone, the thermal storage joint frequency regulation system determines it as a primary frequency regulation action, and records the current total actual power of the thermal storage and the actual power of the hybrid energy storage system. When the grid frequency deviation exceeds 0.1Hz, the hybrid energy storage system participates in the primary frequency regulation; in the second stage, the hybrid energy storage system participates in the primary frequency regulation according to the energy storage power instruction, wherein the energy storage power instruction = the total actual active power of the thermal storage at the start of the primary frequency regulation + the primary frequency regulation instruction - the actual power of the thermal power unit. In the third stage, when the grid frequency deviation is less than 0.05Hz, the hybrid energy storage system exits the primary frequency regulation, and the energy storage power command remains unchanged; in the fourth stage, when the grid frequency deviation is less than the primary frequency regulation action dead zone, the thermal storage combined frequency regulation system determines that the primary frequency regulation action has ended, and the hybrid energy storage system exits the primary frequency regulation action.

[0072] According to a third aspect of an embodiment of the present invention, a computer device is provided.

[0073] In some embodiments, the computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0074] According to a fourth aspect of embodiments of the present invention, a computer-readable storage medium is provided.

[0075] In one embodiment, the computer-readable storage medium stores a computer program, and the computer program implements the steps of the above method when executed by a processor.

[0076] The technical solution provided by the embodiment of the present invention may have the following beneficial effects:

[0077] The present invention proposes a method for combined frequency regulation of a deeply coupled hybrid energy storage and a thermal power unit. The method comprehensively considers the differences in the regulation characteristics of supercapacitors, lithium batteries, and thermal power units, and specifically designs a combined frequency regulation strategy. The total target value of the combined frequency regulation of the thermal storage is divided into three sections according to the AGC evaluation index, so that the AGC regulation performance index reaches the best; the load instruction of the thermal power unit adopts a variable rate regulation method, and the load instruction change rate of the thermal power unit is dynamically adjusted according to the main steam pressure parameter, the main steam pressure fluctuation range is reduced, and the unit economy is improved; different supercapacitor and lithium battery matching strategies are designed according to the different regulation requirements between the response time period, the regulation rate section, and the regulation accuracy section; in the waiting area of ​​the regulation accuracy section, a thermal power unit locking scheme is designed to reduce unit wear and further improve the AGC regulation performance. In addition, the present invention also designs a primary frequency regulation control strategy, which divides the primary frequency regulation into four stages.

[0078] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0080] Figure 1 is a flow chart of a combined frequency regulation method of a hybrid energy storage and a thermal power unit according to an exemplary embodiment;

[0081] Figure 2 is a structural block diagram of a combined frequency regulation system of a hybrid energy storage and a thermal power unit according to an exemplary embodiment;

[0082] Figure 3 is a diagram of a fire-storage joint frequency regulation control architecture according to an exemplary embodiment;

[0083] Figure 4 is a control strategy execution flow chart according to an exemplary embodiment;

[0084] Figure 5 is a schematic diagram of a fire-storage combined frequency regulation control scheme according to an exemplary embodiment;

[0085] Figure 6 is a schematic diagram of a typical AGC adjustment process curve according to an exemplary embodiment;

[0086] Figure 7 The figure is a schematic diagram showing the structure of a computer device according to an exemplary embodiment. DETAILED DESCRIPTION

[0087] The following description and accompanying drawings fully illustrate the specific embodiments of this article so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this article includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0088] The terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. in this document indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this document and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of this document, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, it can also be the internal communication of two elements, it can be a direct connection, or it can be an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0089] As used herein, the term "plurality" means two or more than two, unless otherwise specified.

[0090] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0091] In this article, the term "and / or" is a description of the association relationship between objects, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B.

[0092] It should be understood that, although the various steps in the flow chart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0093] Each module in the device or system of the present application can be implemented in whole or in part by software, hardware, or a combination thereof. The above modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above modules.

[0094] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0095] Figure 1 An embodiment of a combined frequency regulation method of a hybrid energy storage and a thermal power unit of the present invention is shown.

[0096] In this optional embodiment, the combined frequency regulation method of the hybrid energy storage and thermal power unit includes:

[0097] Step S101: configuring a hybrid energy storage system based on supercapacitors and lithium batteries, and optimizing and calculating a target power command for each energy storage converter through an SOC balanced distribution algorithm;

[0098] Step S103, setting the priority of primary frequency regulation control and automatic power generation control, and determining the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority;

[0099] Step S105: Based on the determined control strategy and in combination with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatching power command, thereby completing the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0100] In this optional embodiment, during discharge, the target power command is calculated as follows:

[0101]

[0102] When charging, the target power command is calculated as follows:

[0103]

[0104] In the formula, represents the active power instruction of the i-th energy storage converter;

[0105] represents the remaining power of the i-th energy storage converter;

[0106] n represents the number of energy storage converters;

[0107] P cmd Indicates the total active power command of all energy storage converters in the whole station.

[0108] In this optional embodiment, the setting of the priority of the primary frequency regulation control and the automatic power generation control, and determining the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority includes:

[0109] When the thermal power unit is in the automatic power generation control mode, the hybrid energy storage system executes the automatic power generation control strategy;

[0110] When the grid frequency changes or the thermal power unit receives a simulated disturbance signal from the provincial dispatcher, the hybrid energy storage system executes a frequency regulation control strategy;

[0111] When the primary frequency regulation control conflicts with the automatic generation control, the hybrid energy storage system is set to give priority to the primary frequency regulation control strategy.

[0112] In this optional embodiment, based on the automatic power generation control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, and the joint frequency regulation of the hybrid energy storage system and the thermal power unit is completed, including:

[0113] Process automatic power generation control instructions based on rate limits to generate total target values ​​for thermal power unit load instructions and thermal-storage combined frequency regulation instructions;

[0114] According to the automatic power generation control evaluation index, the total target value of the thermal power generation combined frequency regulation command is divided into a response time period, a regulation rate period and a regulation accuracy period, and the thermal power unit locking command is triggered in the waiting area of ​​the regulation accuracy period;

[0115] Based on the deviation between the main steam pressure value controlled by the boiler and the main steam pressure set value, dynamically adjust the load command change rate of the thermal power unit;

[0116] Determine the coordination strategy between supercapacitors and lithium batteries according to the regulation requirements of the response time period, regulation rate section, and regulation accuracy section;

[0117] Combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, completing the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0118] In this optional embodiment, the automatic power generation control instruction is processed by rate limiting to generate the total target value of the thermal power unit load instruction and the thermal power generation combined frequency regulation instruction, including:

[0119] The automatic power generation control instruction is processed by using the speed limit based on the control of the thermal power unit to generate the load instruction of the thermal power unit;

[0120] The automatic power generation control command is processed by using the speed limit based on the hybrid energy storage system control to generate the total target value of the thermal-storage joint frequency regulation command;

[0121] Among them, within the response time period, the speed limit calculation formula based on the hybrid energy storage system control is:

[0122]

[0123] In the regulation rate section, the speed limit calculation formula based on the hybrid energy storage system control is:

[0124]

[0125] In the formula, v n Indicates the standard regulation rate.

[0126] In this optional embodiment, the automatic power generation control evaluation index includes a regulation rate index, a regulation accuracy index and a response time index.

[0127] In this optional embodiment, the coordination strategy between the supercapacitor and the lithium battery is determined according to the regulation requirements of the response time period, the regulation rate section, and the regulation accuracy section, including:

[0128] In the response time period, the supercapacitor takes priority. When the remaining power of the supercapacitor reaches the limit value, the lithium battery is used for supplementary adjustment.

[0129] In the adjustment speed section, the lithium battery takes priority. When the remaining power of the lithium battery reaches the limit value, the supercapacitor will make additional adjustments.

[0130] In the adjustment accuracy section, the lithium battery is used for adjustment first, and when it reaches the waiting area, the supercapacitor is used for adjustment, and the insufficient adjustment part is supplemented by the lithium battery.

[0131] In this optional embodiment, based on the primary frequency regulation control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, and the joint frequency regulation of the hybrid energy storage system and the thermal power unit is completed, including:

[0132] In the first stage, when the grid frequency deviation exceeds the primary frequency regulation dead zone, the thermal energy storage combined frequency regulation system determines it as a primary frequency regulation action and records the current total actual power of the thermal energy storage and the actual power of the hybrid energy storage system. When the grid frequency deviation exceeds 0.1Hz, the hybrid energy storage system participates in the primary frequency regulation.

[0133] In the second stage, the hybrid energy storage system participates in the primary frequency regulation according to the energy storage power command, where the energy storage power command = the total actual active power of the thermal power plant at the start of the primary frequency regulation + the primary frequency regulation command - the actual power of the thermal power unit.

[0134] In the third stage, when the grid frequency deviation is less than 0.05Hz, the hybrid energy storage system exits the primary frequency regulation, and the energy storage power command remains unchanged;

[0135] In the fourth stage, when the grid frequency deviation is less than the dead zone of the primary frequency regulation action, the thermal-storage combined frequency regulation system determines that the primary frequency regulation action is completed, and the hybrid energy storage system exits the primary frequency regulation action.

[0136] Figure 2 An embodiment of a combined frequency regulation system of a hybrid energy storage and thermal power generation unit of the present invention is shown.

[0137] In this optional embodiment, the combined frequency regulation system of the hybrid energy storage and thermal power generation unit includes:

[0138] A power command calculation module 201 is used to configure a hybrid energy storage system based on supercapacitors and lithium batteries, and optimize and calculate the target power command of each energy storage converter through an SOC balanced distribution algorithm;

[0139] The control strategy determination module 203 is used to set the priority of primary frequency regulation control and automatic power generation control, and determine the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority;

[0140] The joint frequency regulation module 205 is used to control the hybrid energy storage system to quickly respond to the dispatching power instruction based on the determined control strategy and the corresponding target power instruction, so as to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

[0141] In order to facilitate understanding of the above technical solutions of the present invention, the above technical solutions of the present invention are further described below from the perspective of architecture and principle, as follows:

[0142] In view of the problems existing in the existing combined frequency regulation of thermal energy storage, the present invention proposes a method and system for combined frequency regulation of deeply coupled hybrid energy storage and thermal power units. Taking into account the differences in the regulation characteristics of supercapacitors, lithium batteries, and thermal power units, a targeted combined frequency regulation strategy is designed. The total target value of the combined frequency regulation of thermal energy storage is divided into three sections according to the AGC evaluation index, so that the AGC regulation performance index reaches the best; the load command of the thermal power unit adopts a variable rate regulation method, and the load command change rate of the thermal power unit is dynamically adjusted according to the main steam pressure parameters to reduce the fluctuation range of the main steam pressure and improve the unit economy; different supercapacitor and lithium battery matching strategies are designed according to the different regulation requirements between the response time period, regulation rate section, and regulation accuracy section; in the waiting area of ​​the regulation accuracy section, a thermal power unit locking scheme is designed to reduce unit wear and further improve the AGC regulation performance. A primary frequency regulation control strategy is designed, and the primary frequency regulation is divided into four stages.

[0143] 1. Thermal energy storage joint frequency regulation control architecture

[0144] The following is an example of a 350MW thermal power unit equipped with a 5MW / 30S supercapacitor + 5MW / 5MWh lithium battery hybrid energy storage system to illustrate this patent. Other cases of units with different capacities equipped with energy storage systems of different capacities are also applicable to this patent. The hybrid energy storage system is connected to the 6KV bus side of the power plant, and the power of the hybrid energy storage system plus the power of the thermal power unit is sent to the dispatcher as a combined power, and the combined power is used as the basis for rewarding or punishing the power plant.

[0145] Control architecture such as Figure 3 As shown, the coordination controller is the control center of the thermal power generation and storage combined frequency regulation system. It communicates with the booster station monitoring, collects booster station information, and determines the units currently participating in the combined frequency regulation through the electrical main wiring topology. It collects the load instructions and real-time information of the units through the unit measurement and control device, and directly collects energy storage information. It calculates the energy storage instructions according to the combined frequency regulation control strategy, controls the rapid charging and discharging of the energy storage, achieves rapid response to the dispatching power instructions, and realizes the function of combined frequency regulation with thermal power. When the energy storage SOC (State of Charge) exceeds the limit, if the unit load is stable and the power reaches the dispatching target value, the energy storage SOC can be restored to the normal range by charging and discharging the energy storage.

[0146] The execution controller is an execution device for the thermal energy storage combined frequency regulation system to interact with the unit DCS (Distributed Control System) and unit measurement and control. It collects the actual power, speed and other information of the unit through the unit DCS, collects the unit AGC (Automatic Generation Control) instructions issued by the dispatcher through the unit measurement and control, and collects the line switch status at the same time, and sends it to the coordination controller. The coordination controller collects the unit frequency and speed in real time through the execution controller. When the primary frequency regulation function is put into use, if it is detected that the unit frequency or speed exceeds the limit, the purpose of rapid frequency response is achieved by controlling the energy storage output.

[0147] The engineer station is the human-machine interface of the combined frequency regulation system of thermal energy storage. Operation and maintenance personnel can use the engineer station to perform functions, set parameters, monitor data, and analyze historical data on the combined frequency regulation system of thermal energy storage.

[0148] In the thermal-storage combined frequency regulation system, Ethernet communication is used between the coordination controller and the telecontrol device and the energy storage PCS (Power Conversion System). Hard wiring is used for connection and interaction between the execution controller and the unit DCS.

[0149] 2. Control strategy

[0150] like Figure 4 The figure shows the control strategy execution flow chart. The combined thermal-storage frequency regulation is divided into primary frequency regulation control and AGC control. When the thermal power unit is in AGC mode, the hybrid energy storage system executes the AGC control strategy; when the grid frequency changes or the thermal power unit receives a simulated disturbance signal issued by the provincial dispatcher, the hybrid energy storage system executes the primary frequency regulation control strategy; when AGC and primary frequency regulation conflict, the hybrid energy storage system shall give priority to the primary frequency regulation control strategy to ensure that the primary frequency regulation has a higher priority than AGC.

[0151] 2.1) AGC control strategy

[0152] The AGC instructions sent by the dispatcher to the power plant are all step instructions. After arriving at the power plant, the AGC instructions need to be rate limited and become load instructions with a slope.

[0153] Depend on Figure 5 As shown, the AGC command generates the thermal power unit load command L after the rate limit vfire 火 , L 火 After the difference is made with the unit's generating power, the PID controller generates the unit's actuator command; the AGC command is rate-limited v to generate the total target value L of the combined frequency regulation command of fire and storage 总 , using the rapidity and high precision of the energy storage system, the energy storage system can bear L 总The difference between the power generation capacity of the thermal power unit and Figure 6 The shaded part in the figure. The total target value L 总 The regulating performance index of the unit can be optimized. The power generation power of the thermal power unit plus the charging (discharging) power of the energy storage system is equal to L 总 .

[0154] On the one hand, the rapidity and high precision of the energy storage system can improve the regulation performance of thermal power units; on the other hand, Figure 6 It can be seen that v 火 The larger the L 火 The greater the slope, the greater the regulation pressure of the thermal power unit. Equipping an energy storage system can reduce the regulation rate of the thermal power unit. The energy storage system takes on more regulation tasks, which can greatly reduce the regulation pressure of the thermal power unit, reduce equipment loss, and extend the life of the unit.

[0155] The thermal-storage combined frequency regulation strategy aims to optimize the AGC regulation performance of the unit. According to the Implementation Rules for Power Grid Connection Operation Management in XX Province, each time the AGC response regulation performance of the unit is adjusted, the regulation rate index K is used. 1 , Adjustment accuracy index K 2 , response time index K 3 The larger the three indicators are, the better the AGC regulation performance of the unit is. The auxiliary service income of the thermal power unit is related to the regulation performance index. The larger the regulation performance index value is, the more auxiliary service income the unit obtains. The joint frequency regulation control strategy proposed in this technology can make the regulation rate index K 1 , Adjustment accuracy index K 2 , response time index K 3 Achieve the best.

[0156] (1) AGC adjustment is divided into Figure 6 The three stages shown, t 1 ~t 2 is the response time period, t 2 ~t 3 is the adjustment rate section, t 3 ~t 5 To adjust the accuracy segment.

[0157] In t 1 ~t 2 During the response time period: to improve the unit response time index K 3 , so that the combined power of energy storage and generator sets jumps out of the dead zone within 2 seconds, that is, t 2 –t 1 <2s, in this section, the speed limit v is calculated using the following formula:

[0158] (Unit: MW / min)

[0159] For units with a rated capacity of less than 350MW, the dead zone is 1MW; for units with a rated capacity between 350MW and 500MW, the dead zone is 1.5MW; for units with a rated capacity greater than 500MW, the dead zone is 2MW;

[0160] In t 2 ~t 3 In the regulation speed range, the speed limit v is calculated using the following formula:

[0161] (Unit: MW / min)

[0162] v n is the standard regulation rate. Taking into account the differences in regulation characteristics of different types of thermal power units, the thermal power unit with a general direct-blowing pulverizing system and a drum boiler is 1.5% of the rated active power of the unit; the thermal power unit with a general intermediate storage silo pulverizing system is 2% of the rated active power of the unit; the thermal power unit with a circulating fluidized bed unit and burning special types of coal (such as inferior coal, high-moisture and low-calorific value lignite, etc.) is 1% of the rated active power of the unit; the supercritical constant-pressure operating DC furnace unit is 1.0% of the rated active power of the unit.

[0163] In t 3 ~t 5 Within the regulation accuracy range: Considering that the energy storage system can instantly respond to any value within the rated power of the energy storage system, the energy storage system must ensure that the combined power is within t 3 At the moment, the target value is reached from the lower dead zone, that is, Figure 6 P 2 Arrival P 3 , and always keep the combined power equal to P 3 , until the next AGC instruction is received.

[0164] (2) Thermal power units are usually controlled by a coordinated control method of boilers and steam turbines, that is, the steam turbine controls the power generation and the boiler controls the main steam pressure. However, the steam turbine and boiler do not match in terms of regulation speed. The boiler regulation speed is slower than that of the steam turbine. This causes the main steam pressure to fluctuate significantly and deviate from the main steam pressure set value when the unit participates in AGC regulation, thereby reducing the unit's operating efficiency and, in turn, the unit's economy.

[0165] This technology adopts the load instruction L 火 For variable rate regulation mode, v 火 The size of varies with the deviation between the main steam pressure and the main steam pressure setting value. The corresponding relationship is shown in Table 1.

[0166] Table 1 Main steam pressure deviation and v 火 The corresponding relationship between

[0167] Main steam pressure deviation(Mpa) <![CDATA[v 火 (MW / min)]]> 1Mpa<|Main steam pressure deviation| 1% rated load 0.8Mpa<|Main steam pressure deviation|≤1Mpa 1.2% rated load 0.6Mpa<|Main steam pressure deviation|≤0.8Mpa 1.3% rated load 0.4Mpa<|Main steam pressure deviation|≤0.6Mpa 1.4% rated load |Main steam pressure deviation|≤0.4Mpa 1.5% rated load

[0168] The faster the regulation rate of the thermal power unit, the greater the main steam pressure deviation. This technology sets a five-speed variable rate regulation. When the main steam pressure deviation becomes larger, the regulation rate of the thermal power unit is reduced, allowing the hybrid energy storage system to take on more regulation tasks, thereby preventing the main steam pressure deviation from continuing to increase and allowing the main steam pressure to fluctuate within a normal range.

[0169] (3) There are two types of AGC instructions in this technology. The first type is Figure 6 The first adjustment in the thermal power unit load instruction L 火 Arrival P 3 After a period of time, the next AGC command is issued; the second is Figure 6 The second regulation in the thermal power unit load instruction L 火 Not yet reached P 4 , the next AGC instruction has been issued.

[0170] When the first AGC instruction is issued, at t 4 ~t 5 During the time period, trigger Figure 5 The locking command in the lock command is triggered. Figure 5 The PID controller in the control stops adjusting and maintains the current output value unchanged until the next AGC instruction is received, and the locking instruction is released. This control strategy is adopted because in the accuracy maintenance stage t 4 ~t 5 The actual power generation of thermal power units will inevitably be around P 3 The actuators of the units passively and frequently participate in such useless adjustments due to small fluctuations up and down, which will increase the wear of the thermal power units. In addition, due to problems such as inaccurate data transmission and timing, the joint energy storage system and the thermal power units cannot achieve seamless connection on a time scale. There is a time difference between the actual power generated by the thermal power units and the charging (discharging) power of the energy storage system, which causes the joint power distortion and reduces the adjustment accuracy. After the locking command is triggered, the energy storage system is adjusted separately, which can not only reduce unnecessary losses of the unit, but also greatly improve the adjustment accuracy.

[0171] When the second AGC instruction is issued, it is not triggered Figure 5 The locking command in the control panel maintains normal regulation.

[0172] (4) Power distribution between supercapacitors and lithium batteries: Considering the advantages and disadvantages of supercapacitors with small capacity and long life and lithium batteries with large capacity and short life, the power distribution between supercapacitors and lithium batteries is: 1 ~t 2 In the response time period, the time is short, so the supercapacitor takes priority in the regulation. When the supercapacitor SOC reaches the limit value, the lithium battery will supplement the regulation. 2 ~t 3In the regulation rate range, the regulation time is long and the regulation range is large, so the lithium battery is preferentially regulated. When the lithium battery SOC reaches the limit value, the supercapacitor is supplemented with regulation. 3 ~t 5 Within the adjustment accuracy range, t 3 ~t 4 The lithium battery in the segment participates in the regulation. 4 ~t 5 The supercapacitor in the segment participates in the regulation, and the insufficient regulation is supplemented by the lithium battery.

[0173] 2.2) One-time frequency modulation strategy

[0174] Phase 1: When the grid frequency deviation exceeds the primary frequency regulation dead zone, the thermal energy storage combined frequency regulation system determines the primary frequency regulation action and records the total thermal energy storage and energy storage actual generation at this time. When the grid frequency deviation exceeds 0.1Hz, energy storage participates in the primary frequency regulation.

[0175] The second stage: The hybrid energy storage system participates in the primary frequency regulation according to the energy storage power command, where the energy storage power command = the total actual active power of the thermal power plant at the start of the primary frequency regulation + the primary frequency regulation command - the actual power of the thermal power unit.

[0176] Phase 3: When the grid frequency deviation is less than 0.05Hz, the energy storage will exit the primary frequency regulation. The energy storage active power command remains unchanged.

[0177] The fourth stage: When the grid frequency deviation is less than the dead zone of the primary frequency regulation action, the thermal-storage combined frequency regulation system determines that the primary frequency regulation action has been restored and exits the primary frequency regulation action.

[0178] 2.3) The battery and capacitor are allocated according to the SOC balancing strategy

[0179] The core idea of ​​the SOC balanced allocation algorithm is to optimize and calculate the target power command of each PCS based on the remaining power of each PCS, and ultimately achieve the optimization goal of equal SOC of PCS. The calculation formula is as follows:

[0180] When discharging (P cmd >0):

[0181]

[0182] When charging (P cmd <0):

[0183]

[0184] In the formula, represents the active power instruction of the i-th energy storage converter;

[0185] represents the remaining power of the i-th energy storage converter;

[0186] n represents the number of energy storage converters;

[0187] P cmd Indicates the total active power command of all energy storage converters in the whole station.

[0188] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 7 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store static information and dynamic information data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in the above method embodiment are implemented.

[0189] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0190] In addition, the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiment when executing the computer program.

[0191] In addition, the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are implemented.

[0192] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0193] The present invention is not limited to the structures which have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A combined frequency modulation method of hybrid energy storage and thermal power generation units, characterized in that: include: Based on the hybrid energy storage system configured with supercapacitors and lithium batteries, the target power command of each energy storage converter is optimized and calculated through the SOC balanced distribution algorithm; Set the priority of primary frequency regulation control and automatic generation control, and determine the primary frequency regulation control strategy or automatic generation control strategy according to the frequency regulation control events and priorities; Based on the determined control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

2. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 1 is characterized in that: During discharge, the target power command is calculated as follows: When charging, the target power command is calculated as follows: In the formula, represents the active power instruction of the i-th energy storage converter; represents the remaining power of the i-th energy storage converter; n represents the number of energy storage converters; P cmd It indicates the total active power command of all energy storage converters in the whole station.

3. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 1 is characterized in that: The setting of the priority of the primary frequency regulation control and the automatic power generation control, and determining the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority includes: When the thermal power unit is in the automatic power generation control mode, the hybrid energy storage system executes the automatic power generation control strategy; When the grid frequency changes or the thermal power unit receives a simulated disturbance signal from the provincial dispatcher, the hybrid energy storage system executes a frequency regulation control strategy; When the primary frequency regulation control conflicts with the automatic generation control, the hybrid energy storage system is set to give priority to the primary frequency regulation control strategy.

4. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 2 is characterized in that: Based on the automatic power generation control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit, including: Process automatic power generation control instructions based on rate limits to generate total target values ​​for thermal power unit load instructions and thermal-storage combined frequency regulation instructions; According to the automatic power generation control evaluation index, the total target value of the thermal power generation combined frequency regulation command is divided into a response time period, a regulation rate period and a regulation accuracy period, and the thermal power unit locking command is triggered in the waiting area of ​​the regulation accuracy period; Based on the deviation between the main steam pressure value controlled by the boiler and the main steam pressure set value, dynamically adjust the load command change rate of the thermal power unit; Determine the coordination strategy between supercapacitors and lithium batteries according to the regulation requirements of the response time period, regulation rate section, and regulation accuracy section; Combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, completing the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

5. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 4 is characterized in that: The automatic power generation control instruction is processed by rate limiting to generate the total target value of the thermal power unit load instruction and the thermal power storage combined frequency regulation instruction, including: The automatic generation control instruction is processed by utilizing the speed limit based on the control of the thermal power unit to generate the load instruction of the thermal power unit; The automatic power generation control command is processed by using the speed limit based on the hybrid energy storage system control to generate the total target value of the thermal-storage joint frequency regulation command; Among them, within the response time period, the speed limit calculation formula based on the hybrid energy storage system control is: In the regulation rate section, the speed limit calculation formula based on the hybrid energy storage system control is: In the formula, v n Indicates the standard regulation rate.

6. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 4 is characterized in that: The automatic power generation control evaluation index includes a regulation rate index, a regulation accuracy index and a response time index.

7. The combined frequency modulation method of hybrid energy storage and thermal power generation unit according to claim 4 is characterized in that: The method of determining the coordination strategy between the supercapacitor and the lithium battery according to the regulation requirements of the response time period, the regulation rate section, and the regulation accuracy section includes: In the response time period, the supercapacitor takes priority. When the remaining power of the supercapacitor reaches the limit value, the lithium battery is used for supplementary adjustment. In the adjustment speed section, the lithium battery takes priority. When the remaining power of the lithium battery reaches the limit value, the supercapacitor will make additional adjustments. In the adjustment accuracy section, the lithium battery is used for adjustment first, and when it reaches the waiting area, the supercapacitor is used for adjustment, and the insufficient adjustment part is supplemented by the lithium battery.

8. The combined frequency modulation method of hybrid energy storage and thermal power generation units according to claim 1 is characterized in that: Based on the primary frequency regulation control strategy, combined with the corresponding target power command, the hybrid energy storage system is controlled to quickly respond to the dispatch power command, and the joint frequency regulation of the hybrid energy storage system and the thermal power unit is completed, including: In the first stage, when the grid frequency deviation exceeds the primary frequency regulation dead zone, the thermal energy storage combined frequency regulation system determines it as a primary frequency regulation action and records the current total actual power of the thermal energy storage and the actual power of the hybrid energy storage system. When the grid frequency deviation exceeds 0.1Hz, the hybrid energy storage system participates in the primary frequency regulation. In the second stage, the hybrid energy storage system participates in the primary frequency regulation according to the energy storage power command, where the energy storage power command = the total actual active power of the thermal power plant at the start of the primary frequency regulation + the primary frequency regulation command - the actual power of the thermal power unit. In the third stage, when the grid frequency deviation is less than 0.05Hz, the hybrid energy storage system exits the primary frequency regulation, and the energy storage power command remains unchanged; In the fourth stage, when the grid frequency deviation is less than the dead zone of the primary frequency regulation action, the thermal-storage combined frequency regulation system determines that the primary frequency regulation action is completed, and the hybrid energy storage system exits the primary frequency regulation action.

9. A combined frequency modulation system of hybrid energy storage and thermal power generation units, characterized in that: include: The power command calculation module is used to configure a hybrid energy storage system based on supercapacitors and lithium batteries, and optimize the calculation of the target power command of each energy storage converter through the SOC balanced distribution algorithm; A control strategy determination module is used to set the priority of primary frequency regulation control and automatic power generation control, and determine the primary frequency regulation control strategy or automatic power generation control strategy according to the frequency regulation control event and priority; The joint frequency regulation module is used to control the hybrid energy storage system to quickly respond to the dispatching power command based on the determined control strategy and the corresponding target power command, so as to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

10. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: During discharge, the target power command is calculated as follows: When charging, the target power command is calculated as follows: In the formula, represents the active power instruction of the i-th energy storage converter; represents the remaining power of the i-th energy storage converter; n represents the number of energy storage converters; P cmd It indicates the total active power command of all energy storage converters in the whole station.

11. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: The control strategy determination module sets the priority of primary frequency regulation control and automatic power generation control, and determines the primary frequency regulation control strategy or the automatic power generation control strategy according to the frequency regulation control event and the priority. When the thermal power unit is in the automatic power generation control mode, the hybrid energy storage system executes the automatic power generation control strategy; when the grid frequency changes or the thermal power unit receives a simulated disturbance signal issued by the provincial dispatching station, the hybrid energy storage system executes the primary frequency regulation control strategy; when the primary frequency regulation control conflicts with the automatic power generation control, the hybrid energy storage system is set to give priority to the primary frequency regulation control strategy.

12. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: The joint frequency regulation module controls the hybrid energy storage system to quickly respond to the dispatching power instruction based on the automatic power generation control strategy and in combination with the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit. Based on the rate limit, the automatic power generation control instruction is processed to generate the load instruction of the thermal power unit and the total target value of the fire-storage joint frequency regulation instruction; the total target value of the fire-storage joint frequency regulation instruction is divided into a response time period, an adjustment rate section and an adjustment accuracy section according to the automatic power generation control evaluation index, and the thermal power unit locking instruction is triggered in the waiting area of ​​the adjustment accuracy section; based on the deviation between the main steam pressure value of the boiler control and the main steam pressure set value, the load instruction change rate of the thermal power unit is dynamically adjusted; the coordination strategy between the supercapacitor and the lithium battery is determined according to the regulation requirements of the response time period, the adjustment rate section and the adjustment accuracy section; the hybrid energy storage system is controlled to quickly respond to the dispatching power instruction in combination with the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit.

13. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: When the joint frequency regulation module processes the automatic power generation control instruction through rate limiting to generate the load instruction of the thermal power unit and the total target value of the thermal energy storage joint frequency regulation instruction, the automatic power generation control instruction is processed by the speed limit based on the control of the thermal power unit to generate the load instruction of the thermal power unit; the automatic power generation control instruction is processed by the speed limit based on the control of the hybrid energy storage system to generate the total target value of the thermal energy storage joint frequency regulation instruction; Among them, within the response time period, the speed limit calculation formula based on the hybrid energy storage system control is: In the regulation rate section, the speed limit calculation formula based on the hybrid energy storage system control is: In the formula, v n Indicates the standard regulation rate.

14. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: The automatic power generation control evaluation index includes a regulation rate index, a regulation accuracy index and a response time index.

15. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: When the joint frequency modulation module determines the coordination strategy between the supercapacitor and the lithium battery according to the regulation requirements of the response time period, the regulation rate section, and the regulation accuracy section, the supercapacitor participates first in the response time period, and when the remaining power of the supercapacitor reaches the limit value, the lithium battery performs supplementary regulation; in the regulation rate section, the lithium battery participates first in the regulation, and when the remaining power of the lithium battery reaches the limit value, the supercapacitor performs supplementary regulation; in the regulation accuracy section, the lithium battery participates in the regulation first, and when it reaches the waiting area, the supercapacitor participates in the regulation, and the insufficient regulation is supplemented by the lithium battery.

16. The combined frequency modulation system of hybrid energy storage and thermal power generation units according to claim 9 is characterized in that: The joint frequency regulation module controls the hybrid energy storage system to quickly respond to the dispatching power instruction based on the primary frequency regulation control strategy and the corresponding target power instruction to complete the joint frequency regulation of the hybrid energy storage system and the thermal power unit. In the first stage, when the grid frequency deviation exceeds the primary frequency regulation action dead zone, the thermal storage joint frequency regulation system determines it as a primary frequency regulation action and records the current total actual power of the thermal storage and the actual power of the hybrid energy storage system. When the grid frequency deviation exceeds 0.1Hz, the hybrid energy storage system participates in the primary frequency regulation. In the second stage, the hybrid energy storage system participates in the primary frequency regulation according to the energy storage power instruction, wherein the energy storage power instruction = the total actual active power of the thermal storage at the start of the primary frequency regulation + the primary frequency regulation instruction - the actual power of the thermal power unit. In the third stage, when the grid frequency deviation is less than 0.05Hz, the hybrid energy storage system exits the primary frequency regulation, and the energy storage power command remains unchanged; in the fourth stage, when the grid frequency deviation is less than the primary frequency regulation action dead zone, the thermal storage combined frequency regulation system determines that the primary frequency regulation action has ended, and the hybrid energy storage system exits the primary frequency regulation action.

Images