Control method for frequency modulation of thermal power generating unit assisted by compressed air energy storage compressor

Abstract

The invention discloses a control method for frequency modulation of a thermal power generating unit assisted by a compressed air energy storage compressor, which relates to the technical field of power systems and comprises the following steps of: acquiring a real-time frequency signal of a power grid, and calculating a frequency difference and a frequency change rate according to a control strategy for active control of the compressed air energy storage compressor and the thermal power generating unit; according to a frequency change rate threshold value calculated by the frequency response adjustment deviation threshold value, a frequency change interval where the frequency change rate is located is judged; and based on the frequency change interval of the frequency change rate, the control system controls the compressed air energy storage compressor to be matched with the thermal power generating unit to jointly adjust the power grid frequency. According to the method, through a control strategy of active control of the compressed air energy storage compressor and the thermal power generating unit, the compressed air energy storage compressor can assist the thermal power generating unit in quickly responding to frequency adjustment of the power system in the energy storage stage, so that a relatively large frequency difference possibly occurring in the system can be effectively eliminated in advance; and the influence of power disturbance is prevented from being further increased.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a control method for frequency modulation of a compressed air energy storage compressor assisted thermal power generation unit. Background Art

[0002] With the continuous increase in the proportion of new energy installed capacity, a "new power system" with new energy as its main feature is gradually taking shape. However, the high proportion of new energy connected to the grid has reduced the inertia level and frequency support capacity of the power system, and has strong intermittent and volatile power generation. The frequency stability problem has become one of the core issues of the current power grid security and stability and the efficient absorption of new energy. The traditional thermal power units have a slow frequency regulation response speed and it is difficult to meet the power system's demand for rapid frequency regulation after the access of new energy. In order to improve the solution to the problem of grid frequency stability and increase the technical means and methods to solve the frequency stability problem, the requirements for various grid-connected entities to participate in power auxiliary services are getting higher and higher. Compressed air energy storage technology with high capacity, flexible start and stop, long operating life and high safety has also made rapid progress and development. However, domestic compressed air energy storage research still focuses on the improvement of single-machine capacity, and there is still a blank in the field of auxiliary services. Mastering the performance of compressed air energy storage power generation systems in participating in auxiliary services is the only way to achieve flexible and effective regulation.

[0003] Compressed air energy storage technology, as a large-scale energy storage technology, has received extensive attention and development in recent years. It has the advantages of large capacity, long life, safety and reliability, and has broad application prospects in power systems. The existing research on the performance of compressed air energy storage participating in the primary frequency regulation on the load side is just in its infancy and there are still many shortcomings. The existing technology mainly focuses on the power control means and methods of the system compressor, and is basically in the theoretical and simulation research stage. The load-side frequency regulation response control means are missing and technical research is insufficient. At the same time, its response rate and accuracy to the grid frequency, frequency regulation response control strategy technology and other aspects still need to be studied urgently. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] The technical problem solved by the present invention is that the existing technology has few research results on the frequency response control method of compressed air energy storage compressor (load side) and has solved the problem of how to intervene in the frequency difference response in advance before a large frequency difference occurs in the power grid to ensure rapid recovery of system fluctuations.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a control method for a compressed air energy storage compressor to assist in frequency modulation of a thermal power unit, comprising collecting real-time frequency signals of a power grid, calculating a frequency difference and a frequency change rate according to a control strategy for active power control of the compressed air energy storage compressor and the thermal power unit; adjusting a frequency change rate threshold calculated according to a frequency response deviation threshold, and discerning a frequency change interval in which the frequency change rate is located; based on the frequency change interval in which the frequency change rate is located, a control system controls the power consumption of the compressed air energy storage compressor to coordinate with the power output of the thermal power unit, and jointly adjusts the power grid frequency.

[0007] As a preferred solution of the control method for frequency modulation of a compressed air energy storage compressor assisted thermal power unit according to the present invention, wherein: the calculation of the frequency difference and the frequency change rate includes obtaining the real-time frequency of the power grid, sending the frequency signal to the frequency difference and frequency change rate calculation module, calculating the frequency difference Δf and the frequency change rate The relationship between the frequency difference and the frequency change rate is expressed as:

[0008]

[0009] Where δ(t) is the function of the frequency change rate over time.

[0010] As a preferred solution of the control method for frequency modulation of a compressed air energy storage compressor assisted thermal power unit according to the present invention, the frequency response adjustment deviation threshold includes taking 0.2 Hz as the frequency response adjustment deviation threshold β, setting 2 intervals, expressed as:

[0011] 0≤|Δf|≤β

[0012] β≤|Δf|

[0013] According to the different intervals of the frequency difference, the active power output of the units within the regional power grid is adjusted, and the compressed air energy storage compressor is controlled to adjust the active power.

[0014] As a preferred solution of the control method of the compressed air energy storage compressor assisting the frequency modulation of the thermal power unit described in the present invention, the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit includes considering the change range and amplitude of the frequency change rate under different frequency difference ranges, taking the amplitude of the frequency change rate as a constraint limit, and quickly responding to the load adjustment demand; considering the frequency response method of the thermal power unit in the traditional mode, the simplified characteristics of the thermal power unit responding to the frequency modulation alone are expressed as:

[0015]

[0016] Where ΔP g is the power of the thermal power unit in response to frequency modulation, T G1is the time constant of the primary frequency regulation response of the thermal power unit, R is the unit adjustment coefficient, and Δf is the frequency deviation; after adding the compressed air energy storage compressor load regulation, the rapidity of the compressed air energy storage device is used as the load to undertake the frequency regulation task in the initial stage, the response time constant of the thermal power unit is reduced, the system steady-state power balance is guaranteed to remain unchanged, the combined system adjustment coefficient remains unchanged, and the primary frequency regulation characteristic equation of the combined system is expressed as:

[0017]

[0018] Among them, T G2 is the primary frequency modulation response time constant of the combined system, ΔP u is the total active power output of the combined system; the total active power output of the combined system is calculated as:

[0019] ΔP u =ΔP g -ΔP c

[0020] Where ΔP g is the change in active output of the thermal power unit; calculate the change in active power of the compressed air energy storage compressor, expressed as:

[0021]

[0022] Where ΔP c is the change in active power consumed by the energy storage compressor.

[0023] As a preferred solution of the control method of the compressed air energy storage compressor assisting the frequency modulation of the thermal power unit described in the present invention, wherein: the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit also includes introducing the differential coefficient R of the compressed air energy storage compressor to participate in the primary frequency modulation c , calculate the active power change of the compressed air energy storage compressor, expressed as:

[0024]

[0025] Among them, R c is the differential coefficient of the compressed air energy storage compressor participating in the primary frequency modulation; calculate M 1 , expressed as:

[0026]

[0027] Among them, M 1 It is the primary frequency modulation control coefficient of the energy storage side response of the compressed air energy storage system.

[0028] As a preferred solution of the control method of the compressed air energy storage compressor assisting the frequency modulation of the thermal power unit described in the present invention, wherein: the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit also includes when the system has an external power disturbance deviation ΔP L , when the frequency difference Δf appears, the control branch With another control branch conduct The active power change ΔP consumed by the energy storage compressor is calculated together c , ΔP c The transfer function G of the thermal power unit g (s) The response power ΔP of the thermal power unit when responding to frequency modulation g ΔP g -ΔP comparison to obtain the overall active output ΔP of the combined system u , ΔP u With ΔP L For comparison, if ΔP u =ΔP L , then the combined system frequency modulation ends, if |ΔP u |<|ΔP L |, then the remaining ΔP L Gain Then continue to repeat the frequency modulation until ΔP u With ΔP L The frequency modulation ends by canceling each other out;

[0029] The transfer function of the control calculation thermal power unit is expressed as:

[0030]

[0031] Among them, G g (s) is the transfer function of the thermal power unit, T g is the speed regulator time constant, T r is the reheat time constant, T t is the turbine time constant, K h is the power ratio of the high pressure cylinder, and s is the variable s in the Laplace transform.

[0032] As a preferred solution of the control method of the compressed air energy storage compressor assisting the frequency modulation of the thermal power unit described in the present invention, wherein: the threshold value of the frequency change rate includes considering the external load disturbance deviation, and the system dynamic response equation is expressed as:

[0033]

[0034] Where H is the generator moment of inertia, D is the load damping coefficient; ΔP c The fast response expression is expressed as:

[0035]

[0036] At the beginning of the disturbance, due to the influence of inertia, the change of Δf is small, and the adjustment range of the thermal power unit is not large, but the frequency change rate will have a large response. Therefore, it is approximately considered that Δf = 0. As a fast response of primary frequency modulation, the approximate response expression of the compressed air energy storage compressor is obtained, which is expressed as:

[0037]

[0038] The initial rapid response of the compressed air energy storage compressor is an expression of the frequency change rate and the external power disturbance; the system is at t 1 When the disturbance comes, the system has inertia Δf=0, t 2 When the frequency difference reaches the stable value Δf st ,δ(t)=0| t＝t2 , in the adjustment process, the frequency change rate is expressed by interval division to limit the adjustment amplitude of the compressed air energy storage compressor when the frequency change rate falls in different intervals when the disturbance amplitude is different;

[0039] t 1 The system response at time is expressed as:

[0040]

[0041] t 2 The system response at time is expressed as:

[0042]

[0043] t 2 At this moment, calculate ΔP c , expressed as:

[0044]

[0045] Replace Δf with the steady-state frequency deviation threshold β st The inverse order of magnitude of the system load damping coefficient, the energy storage compressor adjustment coefficient, and the thermal power unit adjustment coefficient has a large deviation, t 2 The system response at time is expressed as:

[0046]

[0047] Since the disturbance exists after it arrives, ΔP L | t＝t1 =ΔP L | t＝t2 , at t 1 At this moment, disturbance comes, ΔP c No response, indicated by:

[0048]

[0049] Among them, δ(t 1 ) is the threshold value of the frequency change rate δ 1 ; The frequency change rate interval includes interval I and interval II, which can be expressed as:

[0050] Interval I: 0≤∣δ∣≤∣δ 1 ∣

[0051] Interval II: |δ 1 ∣≤∣δ∣

[0052] When the system fluctuation causes the frequency change rate to fall within interval I and the change amplitude is small, the frequency difference changes little. The energy storage compressor takes the lead in action according to the frequency change rate and adjusts its own operation to respond to load fluctuations. When the frequency change rate falls within interval II, after the energy storage compressor responds, a large frequency difference will appear in the system. The thermal power units respond to active power fluctuations according to the frequency difference and jointly adjust the system disturbance.

[0053] Another object of the present invention is to provide a control system for frequency regulation of thermal power units assisted by compressed air energy storage compressors, which can assist thermal power units in regional power grids to quickly respond to power system frequency adjustments during the energy storage stage through compressed air energy storage compressors, thereby making up for the lack of load-side frequency regulation response control means and insufficient technical research.

[0054] As a preferred solution of the control system for the compressed air energy storage compressor assisting the frequency modulation of the thermal power unit described in the present invention, it includes: a calculation module, a judgment module, and an adjustment module; the calculation module is used to collect the real-time frequency signal of the power grid, and calculate the frequency difference and the frequency change rate according to the control strategy of the active power control of the compressed air energy storage compressor and the thermal power unit; the judgment module is used to adjust the frequency response The frequency change rate threshold calculated by the deviation threshold is used to determine the frequency change interval where the frequency change rate is located; the adjustment module is used to control the power consumption of the compressed air energy storage compressor based on the frequency change interval where the frequency change rate is located, and coordinate the power output of the thermal power unit to jointly adjust the power grid frequency.

[0055] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of a control method for a compressed air energy storage compressor to assist in frequency modulation of a thermal power unit.

[0056] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a control method for a compressed air energy storage compressor to assist in frequency modulation of a thermal power unit.

[0057] Beneficial effects of the present invention: The control method for the compressed air energy storage compressor to assist the thermal power unit in frequency modulation provided by the present invention can enable the compressed air energy storage compressor to assist the thermal power unit in quickly responding to the frequency adjustment of the power system during the energy storage stage through the control strategy of the active power control of the compressed air energy storage compressor and the thermal power unit, thereby providing a method on the load side that can effectively eliminate the large frequency difference that may occur in the system in advance and quickly prevent the impact of power disturbances from further increasing. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0059] Figure 1 An overall flow chart of a control method for frequency modulation of a thermal power unit assisted by a compressed air energy storage compressor provided in the first embodiment of the present invention.

[0060] Figure 2 A control strategy diagram of the active power control of a compressed air energy storage compressor and a thermal power unit in a control method for frequency modulation of a compressed air energy storage compressor assisted by a thermal power unit provided in the first embodiment of the present invention.

[0061] Figure 3 An overall flow chart of a control system for a compressed air energy storage compressor to assist in frequency regulation of a thermal power unit provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0063] Example 1, reference Figure 1-Figure 2 , which is an embodiment of the present invention, provides a control method for frequency modulation of a compressed air energy storage compressor assisted thermal power unit, comprising:

[0064] S1: Collect the real-time frequency signal of the power grid, and calculate the frequency difference and frequency change rate according to the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit.

[0065] Furthermore, the calculation of the frequency difference and the frequency change rate includes obtaining the real-time frequency of the power grid, sending the frequency signal to the frequency difference and frequency change rate calculation module, and calculating the frequency difference Δf and the frequency change rate The relationship between the frequency difference and the frequency change rate is expressed as:

[0066]

[0067] Where δ(t) is the function of the frequency change rate over time.

[0068] It should be noted that by calculating the real-time frequency of the power grid, it is possible to determine whether the power grid frequency deviates from the normal range. The results of calculating the frequency difference and the frequency change rate will be used as input for subsequent control strategies. For example, the power output adjustment of the compressed air energy storage compressor and the thermal power unit can be guided by determining the frequency change rate interval in which the frequency change rate is located.

[0069] S2: adjusting the frequency change rate threshold calculated by the deviation threshold according to the frequency response to determine the frequency change interval in which the frequency change rate is located;

[0070] Furthermore, the frequency response adjustment deviation threshold includes taking 0.2 Hz as the frequency response adjustment deviation threshold β and setting two intervals, which are expressed as:

[0071] 0≤|Δf|≤β

[0072] β≤|Δf|

[0073] According to the different intervals of the frequency difference, the active power output of the units within the regional power grid is adjusted, and the compressed air energy storage compressor is controlled to adjust the active power.

[0074] It should be noted that the control strategy for the active power control of the compressed air energy storage compressor and the thermal power unit includes considering the change range and amplitude of the frequency change rate under different frequency difference ranges, taking the amplitude of the frequency change rate as a constraint limit, and quickly responding to the load adjustment demand; considering the frequency response method of integrated thermal energy storage, the simplified characteristics of the thermal power unit responding to the primary frequency modulation alone in the traditional mode are expressed as:

[0075]

[0076] Where ΔP g is the power of the thermal power unit in response to frequency modulation, T G1 is the time constant of the primary frequency regulation response of the thermal power unit, R is the unit adjustment coefficient, and Δf is the frequency deviation; after adding the compressed air energy storage compressor load regulation, the rapidity of the compressed air energy storage device is used as the load to undertake the frequency regulation task in the initial stage, the response time constant of the thermal power unit is reduced, the system steady-state power balance is guaranteed to remain unchanged, the combined system adjustment coefficient remains unchanged, and the primary frequency regulation characteristic equation of the combined system is expressed as:

[0077]

[0078] Among them, T G2 is the primary frequency modulation response time constant of the combined system, ΔP u is the total active power output of the combined system; the total active power output of the combined system is calculated as:

[0079] ΔP u =ΔP g -ΔP c

[0080] Where ΔP g is the change in active output of the thermal power unit; calculate the change in active power of the compressed air energy storage compressor, expressed as:

[0081]

[0082] Where ΔP c is the change in active power consumed by the energy storage compressor.

[0083] It should also be noted that the control strategy for the active power control of the compressed air energy storage compressor and the thermal power unit also includes the introduction of the differential coefficient R of the compressed air energy storage compressor to participate in the primary frequency regulation. c , calculate the active power change of the compressed air energy storage compressor, expressed as:

[0084]

[0085] Among them, R c is the differential coefficient of the compressed air energy storage compressor participating in the primary frequency modulation; calculate M 1 , expressed as:

[0086]

[0087] Among them, M 1 It is the primary frequency modulation control coefficient of the energy storage side response of the compressed air energy storage system.

[0088] It should also be noted that the control strategy for the active power control of the compressed air energy storage compressor and the thermal power unit also includes the control of the system when an external power disturbance deviation ΔP L , when the frequency difference Δf appears, the control branch With another control branch conduct The active power change ΔP consumed by the energy storage compressor is calculated together c , ΔP c The transfer function G of the thermal power unit g (s) The response power ΔP of the thermal power unit when responding to frequency modulation gΔP g -ΔP comparison to obtain the overall active output ΔP of the combined system u , ΔP u With ΔP L For comparison, if ΔP u =ΔP L , then the combined system frequency modulation ends, if |ΔP u |<|ΔP L |, then the remaining ΔP L Gain Then continue to repeat the frequency modulation until ΔP u With ΔP L The frequency modulation ends after mutual cancellation; the transfer function of the thermal power unit is calculated and expressed as:

[0089]

[0090] Among them, Gg(s) is the transfer function of the thermal power unit, T g is the speed regulator time constant, T r is the reheat time constant, T t is the turbine time constant, K h is the power ratio of the high pressure cylinder, and s is the variable s in the Laplace transform.

[0091] It should also be noted that the reason for choosing 0.2Hz as the frequency response adjustment deviation threshold β is based on the requirements in GB / T15945-2008: Under normal operating conditions of the power system, the absolute value of the frequency deviation should be within 0.2Hz, and it can be relaxed to 0.5Hz when the system capacity is small.

[0092] S3: Based on the frequency change interval in which the frequency change rate is located, the control system controls the power consumption of the compressed air energy storage compressor to coordinate with the power output of the thermal power unit to jointly adjust the grid frequency.

[0093] Furthermore, the threshold of the frequency change rate includes consideration of the external load disturbance deviation, and the system dynamic response equation is expressed as:

[0094]

[0095] Where H is the generator moment of inertia, D is the load damping coefficient; ΔP c The fast response expression is expressed as:

[0096]

[0097] At the beginning of the disturbance, due to the influence of inertia, the change of Δf is small, and the adjustment range of the thermal power unit is not large, but the frequency change rate will have a large response. Therefore, it is approximately considered that Δf = 0. As a fast response of primary frequency modulation, the approximate response expression of the compressed air energy storage compressor is obtained, which is expressed as:

[0098]

[0099] The initial rapid response of the compressed air energy storage compressor is an expression of the frequency change rate and the external power disturbance; the system is at t 1 When the disturbance comes, the system has inertia Δf=0, t 2 When the frequency difference reaches the stable value Δf st ,δ(t)=0| t＝t2 , in the adjustment process, the frequency change rate is expressed by interval division to limit the adjustment amplitude of the compressed air energy storage compressor when the frequency change rate falls in different intervals when the disturbance amplitude is different;

[0100] t 1 The system response at time is expressed as:

[0101]

[0102] t 2 The system response at time is expressed as:

[0103]

[0104] t 2 At this moment, calculate ΔP c , expressed as:

[0105]

[0106] Replace Δf with the steady-state frequency deviation threshold β st The inverse order of magnitude of the system load damping coefficient, the energy storage compressor adjustment coefficient, and the thermal power unit adjustment coefficient has a large deviation, t 2 The system response at time is expressed as:

[0107]

[0108] Since the disturbance exists after it arrives, ΔP L | t＝t1 =ΔP L | t＝t2 , at t 1 At this moment, disturbance comes, ΔP c No response, indicated by:

[0109]

[0110] Among them, δ(t 1 ) is the threshold value of the frequency change rate δ 1 ; The frequency change rate interval includes interval I and interval II, which can be expressed as:

[0111] Interval I: 0≤∣δ∣≤∣δ 1 ∣

[0112] Interval II: |δ 1 ∣≤∣δ∣

[0113] When the system fluctuation causes the frequency change rate to fall within interval I and the change amplitude is small, the frequency difference changes little. The energy storage compressor takes the lead in action according to the frequency change rate and adjusts its own operation to respond to load fluctuations. When the frequency change rate falls within interval II, after the energy storage compressor responds, a large frequency difference will appear in the system. The thermal power units respond to active power fluctuations according to the frequency difference and jointly adjust the system disturbance.

[0114] It should be noted that β is the preset frequency response adjustment deviation threshold, and Δfst is the actual deviation when the frequency difference reaches a stable value. β is used instead of Δfst because Δfst changes over time, and using it as a threshold will lead to frequent adjustments of the control system. β is a preset value, which can reduce the number of adjustments and improve the response speed of the control system.

[0115] Embodiment 2, an embodiment of the present invention provides a method for controlling the frequency regulation of a compressed air energy storage compressor assisted thermal power unit, comprising: designing an energy storage-thermal power unit for combined operation, wherein the regulation coefficient when the energy storage corresponds to the system frequency change is R c The corresponding adjustment coefficient of the thermal power unit is R, and the primary frequency regulation response time constant of the thermal power unit is T G1 , the combined system operates, and the time for responding to a frequency modulation is T G2 , the generator moment of inertia is H, calculate the threshold value of the frequency change rate δ 1 , and then get the frequency change rate interval. The system calculates and determines the frequency difference and frequency change rate through a fixed time Δt, and uses this as a basis to determine whether the frequency modulation module needs to be started to balance the system disturbance.

[0116] When the system has power ΔP L When there is a disturbance, a frequency difference Δf appears 1 , the frequency change rate δ is obtained by calculation.

[0117] When δ is in interval I: 0≤|δ|≤|δ 1 ∣, the frequency change rate fluctuates slightly, and the frequency difference is within the dead zone of the primary frequency regulation of the thermal power unit. At this time, the primary frequency regulation of the thermal power unit does not work, and the system is controlled as follows:

[0118]

[0119] The active power consumed by the compressor is adjusted to respond to system disturbances and eliminate frequency differences.

[0120] When δ is in interval I: 0≤|δ|≤|δ 1 ∣, the frequency difference is outside the dead zone of the primary frequency regulation of the thermal power unit, and the primary frequency regulation of the thermal power unit starts to act. Due to the early action of the energy storage response, after the action, the system frequency difference is Δf 2 , and |Δf 2 ∣<∣Δf 1 ∣, the system is controlled as follows:

[0121]

[0122] Where the active power consumption of energy storage is insufficient, the thermal power primary frequency modulation responds, and the response frequency difference is Δf 2 .

[0123] When δ is in interval II: |δ 1 When ∣≤∣δ∣, the frequency change rate is very large, the frequency difference changes very quickly, and the probability of a large frequency difference is very high, which will soon exceed the primary frequency regulation dead zone of the thermal power unit. Let the frequency difference at this time be Δf 3 , the frequency difference has the risk of exceeding safety. At this time, the system responds to the energy storage compressor and the thermal power unit at the same time, and the system is controlled as follows:

[0124]

[0125] Where ΔP c Control as follows:

[0126]

[0127] In combination with the above, this embodiment describes in detail how to control the power output of the compressor and the thermal power unit respectively according to the interval in which the frequency change rate is located when a power disturbance occurs in the system, so as to jointly adjust the grid frequency and eliminate the frequency difference. Through the embodiments of the various situations in which the frequency difference falls in interval I and the frequency difference falls in interval II, it can be clearly seen that the present invention provides a method for a compressed air energy storage compressor to assist the thermal power unit in the regional power grid to quickly respond to the frequency adjustment of the power system during the energy storage stage. This method not only makes up for the lack of load-side frequency regulation response control means and insufficient technical research in the power system, but also enables the compressor to be adjusted first and the thermal power unit to perform power adjustment subsequently, so as to eliminate the frequency difference more quickly and prevent the frequency from exceeding the safety range.

[0128] Example 3, reference Figure 3, which is an embodiment of the present invention, provides a control system for frequency regulation of a thermal power unit assisted by a compressed air energy storage compressor, including a calculation module, a judgment module, and an adjustment module.

[0129] The calculation module is used to collect real-time frequency signals of the power grid, and calculate the frequency difference and frequency change rate according to the control strategy of the active power control of the compressed air energy storage compressor and the thermal power unit; the judgment module is used to adjust the frequency change rate threshold calculated according to the frequency response deviation threshold, and identify the frequency change interval where the frequency change rate is located; the adjustment module is used to control the power consumption of the compressed air energy storage compressor and the power output of the thermal power unit based on the frequency change interval where the frequency change rate is located, so as to jointly adjust the power grid frequency.

[0130] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0131] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0132] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0133] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0134] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for controlling the frequency modulation of a compressed air energy storage compressor assisted thermal power unit, characterized in that: include: Collect the real-time frequency signal of the power grid, and calculate the frequency difference and frequency change rate according to the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit; The frequency change rate threshold calculated by adjusting the deviation threshold according to the frequency response is used to determine the frequency change interval in which the frequency change rate is located; Based on the frequency change range in which the frequency change rate is located, the control system controls the power consumption of the compressed air energy storage compressor to coordinate with the power output of the thermal power unit to jointly adjust the grid frequency.

2. The method for controlling the frequency modulation of a compressed air energy storage compressor assisted thermal power unit according to claim 1, characterized in that: The calculation of the frequency difference and the frequency change rate includes obtaining the real-time frequency of the power grid, sending the frequency signal to the frequency difference and frequency change rate calculation module, and calculating the frequency difference Δf and the frequency change rate. The relationship between the frequency difference and the frequency change rate is expressed as: Where δ(t) is the function of the frequency change rate over time.

3. The control method for frequency modulation of a compressed air energy storage compressor assisted thermal power unit according to claim 2, characterized in that: The frequency response adjustment deviation threshold includes taking 0.2 Hz as the frequency response adjustment deviation threshold β and setting two intervals, which are expressed as: 0≤|Δf|≤β β≤|Δf| According to the different intervals of the frequency difference, the active power output of the units within the regional power grid is adjusted, and the compressed air energy storage compressor is controlled to adjust the active power.

4. The method for controlling the frequency modulation of a thermal power unit assisted by a compressed air energy storage compressor as claimed in claim 3, characterized in that: The control strategy for active control of the compressed air energy storage compressor and the thermal power unit includes considering the change range and amplitude of the frequency change rate under different frequency difference ranges, taking the amplitude of the frequency change rate as a constraint limit, and quickly responding to load adjustment requirements; Considering the frequency response method of thermal power generation and storage integration, the simplified characteristics of the thermal power unit responding to the primary frequency modulation in the traditional mode are expressed as: Among them, ΔP g is the power of the thermal power unit in response to frequency modulation, T G1 is the time constant of the primary frequency regulation response of the thermal power unit, R is the unit regulation coefficient, and Δf is the frequency deviation; After adding the compressed air energy storage compressor load regulation, the compressed air energy storage device is used as a load to undertake the frequency regulation task in the initial stage by taking advantage of the rapidity of its action. The response time constant of the thermal power unit is reduced, the system steady-state power balance is guaranteed to remain unchanged, and the combined system adjustment coefficient remains unchanged. The primary frequency regulation characteristic equation of the combined system is expressed as: Among them, T G2 is the primary frequency modulation response time constant of the combined system, ΔP u is the total active output of the combined system; Calculate the overall active output of the combined system, expressed as: ΔP u =ΔP g -ΔP c Among them, ΔP g is the change in active output of thermal power units; Calculate the active power change of the compressed air energy storage compressor, expressed as: Among them, ΔP c is the change in active power consumed by the energy storage compressor.

5. The method for controlling the frequency modulation of a thermal power unit assisted by a compressed air energy storage compressor as claimed in claim 4, characterized in that: The control strategy for the active power control of the compressed air energy storage compressor and the thermal power unit also includes introducing a differential coefficient R of the compressed air energy storage compressor to participate in the primary frequency modulation. c , calculate the active power change of the compressed air energy storage compressor, expressed as: Among them, R c The differential coefficient of the compressed air energy storage compressor participating in primary frequency modulation; Calculate M1, expressed as: Among them, M1 is the primary frequency modulation control coefficient of the energy storage side response of the compressed air energy storage system.

6. The method for controlling the frequency modulation of a thermal power unit assisted by a compressed air energy storage compressor as claimed in claim 5, characterized in that: The control strategy for the active power control of the compressed air energy storage compressor and the thermal power unit also includes when the system has an external power disturbance deviation ΔP L , when the frequency difference Δf appears, the control branch With another control branch conduct The active power change ΔP consumed by the energy storage compressor is calculated together c , ΔP c The transfer function G of the thermal power unit g (s) The response power ΔP of the thermal power unit when responding to frequency modulation g ΔP g -ΔP comparison to obtain the overall active output ΔP of the combined system u , ΔP u With ΔP L For comparison, if ΔP u =ΔP L , then the combined system frequency modulation ends, if |ΔP u |<|ΔP L |, then the remaining ΔP L Gain Then continue to repeat the frequency modulation until ΔP u With ΔP L The frequency modulation ends by canceling each other out; The transfer function of the control calculation thermal power unit is expressed as: Among them, G g (s) is the transfer function of the thermal power unit, T g is the time constant of the thermal power unit speed regulator, T r is the reheat time constant, T t is the turbine time constant, K h is the power ratio of the high pressure cylinder, and s is the variable s in the Laplace transform.

7. The method for controlling the frequency modulation of a thermal power unit assisted by a compressed air energy storage compressor as claimed in claim 6, characterized in that: The threshold of the frequency change rate includes considering the external load disturbance deviation and the system dynamic response equation, which is expressed as: Among them, H is the generator moment of inertia, D is the load damping coefficient; ΔP c The fast response expression is expressed as: At the beginning of the disturbance, due to the influence of inertia, the change of Δf is small, and the adjustment range of the thermal power unit is not large, but the frequency change rate will have a large response. Therefore, it is approximately considered that Δf = 0. As a fast response of primary frequency modulation, the approximate response expression of the compressed air energy storage compressor is obtained, which is expressed as: The initial rapid response of the compressed air energy storage compressor is an expression of the frequency change rate and the external power disturbance; The system is disturbed at time t1. Due to the inertia of the system Δf=0, the frequency difference reaches the stable value Δf at time t2. st ,δ(t)=0│ t＝t2 , in the adjustment process, the frequency change rate is expressed by interval division to limit the adjustment amplitude of the compressed air energy storage compressor when the frequency change rate falls in different intervals when the disturbance amplitude is different; The system response at time t1 is expressed as: The system response at time t2 is expressed as: At time t2, calculate ΔP c , expressed as: Replace Δf with the steady-state frequency deviation threshold β st , the reciprocal order of magnitude of the system load damping coefficient, the energy storage compressor adjustment coefficient, and the thermal power unit adjustment coefficient have large deviations. The system response at time t2 is expressed as: Since the disturbance exists after it arrives, ΔP L │ t＝t1 =ΔP L │ t＝t2 At time t1, the disturbance comes, ΔP c No response, indicated by: Among them, δ(t1) is the threshold value δ1 of the frequency change rate; The frequency change rate interval includes interval I and interval II, which can be expressed as: Interval I: 0≤|δ|≤|δ1| Interval II: |δ1|≤|δ| When the system fluctuation causes the frequency change rate to fall within interval I and the change amplitude is small, the frequency difference changes little. The energy storage compressor takes the lead in action according to the frequency change rate and adjusts its own operation to respond to load fluctuations. When the frequency change rate falls within interval II, after the energy storage compressor responds, a large frequency difference will appear in the system. The thermal power units respond to active power fluctuations according to the frequency difference and jointly adjust the system disturbance.

8. A system using the control method of any one of claims 1 to 7 for assisting the frequency modulation of a thermal power unit with a compressed air energy storage compressor, characterized in that: Including calculation module, judgment module and adjustment module; The calculation module is used to collect real-time frequency signals of the power grid and calculate the frequency difference and frequency change rate according to the control strategy of the compressed air energy storage compressor and the active power control of the thermal power unit; The judging module is used to judge the frequency change interval where the frequency change rate is located according to the frequency change rate threshold calculated by the frequency response adjustment deviation threshold; The adjustment module is used to control the power consumption of the compressed air energy storage compressor and the power output of the thermal power unit based on the frequency change interval where the frequency change rate is located, and jointly adjust the grid frequency.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the control method for the compressed air energy storage compressor to assist the frequency regulation of a thermal power unit as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the control method of the compressed air energy storage compressor assisting the frequency regulation of a thermal power unit according to any one of claims 1 to 7 are implemented.

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