Energy storage frequency modulation method and system using transformer overload capacity

Abstract

The present disclosure provides a method and system for frequency modulation of energy storage using overload capacity of transformer, the method comprising obtaining historical AGC frequency modulation instructions received by a generator set to obtain the frequency of absolute value of the AGC frequency modulation instructions; obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system as the target capacity; when no AGC frequency modulation instruction is received, controlling the molten salt energy storage system to operate normally according to a set load rate; when an AGC frequency modulation instruction is received, determining the maximum load rate of the molten salt energy storage system based on the overload capacity of the transformer of the molten salt energy storage system, obtaining a target regulation power based on the maximum load rate, the set load rate and the rated capacity, and performing frequency modulation on the power system based on the target regulation power. The method according to the present disclosure can improve the power throughput during frequency modulation and is relatively low in cost.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of power system automation, and particularly relates to a method and system for frequency regulation of energy storage by using overload capacity of a transformer. BACKGROUND

[0002] In the "Cogeneration Management Measures" (Energy Development and Reform

[2016] 617), China clearly pointed out that it encourages thermal power units to be equipped with measures such as thermal storage and energy storage to implement deep peak shaving, and gives peak shaving compensation. With the further deepening of China's power system reform, the increase of electric thermal storage peak shaving facilities in thermal power plants and the increase of peak shaving capacity can obtain economic compensation through peak shaving auxiliary market transactions.

[0003] Although the power grid has a great demand for energy storage participating in peak shaving, the income for energy storage investment is relatively low, which is not enough to balance the purchase cost of energy storage facilities. However, energy storage facilities participating in peak shaving can also participate in providing frequency regulation auxiliary services, and among various auxiliary services such as frequency regulation, peak shaving, backup, rotational inertia, climbing, phase modulation, stable control machine cutting, and rapid load cutting, the income of frequency regulation auxiliary services is the highest, so the energy storage facilities for peak shaving begin to transform to provide frequency regulation services.

[0004] However, the energy storage facilities for peak shaving have the characteristics of small power and large energy, and if they are transformed to provide frequency regulation services, more distribution transformers need to be configured to improve power throughput, which requires a relatively large investment cost. Therefore, for existing energy storage facilities, the prior art lacks a frequency regulation method for improving power throughput at a relatively low cost. SUMMARY

[0005] The present disclosure aims to at least solve one of the technical problems in the related art. To this end, the present disclosure provides a method and system for frequency regulation of energy storage by using overload capacity of a transformer, mainly aiming to improve power throughput during frequency regulation at a relatively low cost.

[0006] According to a first aspect of the present disclosure, a method for frequency regulation of energy storage by using overload capacity of a transformer is provided, comprising:

[0007] obtaining historical AGC frequency regulation instructions received by a generator unit to obtain the frequency of absolute values of the AGC frequency regulation instructions;

[0008] obtaining a target capacity based on the frequency, and configuring a rated capacity of a molten salt energy storage system as the target capacity;

[0009] controlling the molten salt energy storage system to normally operate according to a set load rate when no AGC frequency regulation instruction is received;

[0010] Upon receiving the AGC frequency modulation instruction, a maximum load rate of the molten salt energy storage system is determined based on an overload capacity of a transformer of the molten salt energy storage system, a target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency modulated based on the target regulation power.

[0011] In one embodiment of the present disclosure, the target capacity is obtained based on the frequency, including: forming a frequency histogram based on the frequency; and obtaining the target capacity based on power of a frequency peak of the frequency histogram.

[0012] In one embodiment of the present disclosure, the target capacity is obtained based on the power of the frequency peak of the frequency histogram, including: judging whether the frequency histogram has a single-peak feature or a double-peak feature, if the frequency histogram has the single-peak feature, obtaining the target capacity based on power of a frequency peak; and if the frequency histogram has the double-peak feature, selecting a maximum power from powers corresponding to two frequency peaks, and obtaining the target capacity based on the maximum power.

[0013] In one embodiment of the present disclosure, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, including: obtaining a maximum bearing power based on the maximum load rate and the rated capacity; obtaining a basic operation power based on the set load rate and the rated capacity; and obtaining the target regulation power based on the maximum bearing power and the basic operation power.

[0014] In one embodiment of the present disclosure, if the frequency histogram has the single-peak feature, power corresponding to the frequency peak is obtained by fitting the frequency histogram with a normal distribution.

[0015] In one embodiment of the present disclosure, if the frequency histogram has the double-peak feature, power corresponding to two frequency peaks is obtained by fitting the frequency histogram with a Gaussian mixture model.

[0016] According to a second aspect of the present disclosure, a power storage frequency modulation system using an overload capacity of a transformer is also provided, including:

[0017] An obtaining module is configured to obtain historical AGC frequency modulation instructions received by a generator unit to obtain a frequency of absolute values of the AGC frequency modulation instructions;

[0018] A calculating module is configured to obtain a target capacity based on the frequency, and configure a rated capacity of the molten salt energy storage system as the target capacity.

[0019] A control module is configured to control the molten salt energy storage system to normally operate at a set load rate when no AGC frequency modulation instruction is received.

[0020] The frequency modulation module is configured to, when receiving an AGC frequency modulation instruction, determine a maximum load rate of the molten salt energy storage system based on an overload capacity of a transformer of the molten salt energy storage system, obtain a target regulation power based on the maximum load rate, the set load rate and the rated capacity, and perform frequency modulation on the power system based on the target regulation power.

[0021] In one embodiment of the present disclosure, the computing module is specifically configured to: form a frequency histogram based on the frequencies; determine whether the frequency histogram has a unimodal feature or a bimodal feature; if the frequency histogram has the unimodal feature, obtain the target capacity based on the power of the frequency peak; and if the frequency histogram has the bimodal feature, select a maximum power from the powers corresponding to the two frequency peaks, and obtain the target capacity based on the maximum power.

[0022] In one embodiment of the present disclosure, the frequency modulation module is specifically configured to: obtain a maximum bearing power based on the maximum load rate and the rated capacity; obtain a basic operation power based on the set load rate and the rated capacity; and obtain a target regulation power based on the maximum bearing power and the basic operation power.

[0023] According to a third aspect of the present disclosure, a storage energy frequency modulation device using transformer overload capacity is also provided, which comprises: at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the storage energy frequency modulation method using transformer overload capacity according to the first aspect of the present disclosure.

[0024] In one or more embodiments of the present disclosure, a historical AGC frequency modulation instruction received by a generator set is acquired to obtain a frequency of an absolute value of the AGC frequency modulation instruction; a target capacity is obtained based on the frequency, and a rated capacity of the molten salt energy storage system is configured as the target capacity; when no AGC frequency modulation instruction is received, the molten salt energy storage system is controlled to normally operate according to a set load rate; when an AGC frequency modulation instruction is received, a maximum load rate of the molten salt energy storage system is determined based on an overload capacity of a transformer of the molten salt energy storage system, a target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency modulated based on the target regulation power. In this case, the AGC frequency modulation instruction is regarded as a normal periodic load of the molten salt energy storage system by taking advantage of the short power charging and discharging time of the AGC frequency modulation instruction, the target capacity obtained based on the frequency of the AGC frequency modulation instruction is configured as the rated capacity of the molten salt energy storage system, the maximum load rate of the molten salt energy storage system is determined based on the overload capacity of the transformer of the molten salt energy storage system, and the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity to frequency modulate the power system, thereby improving the power throughput during frequency modulation. In addition, the method of the present disclosure utilizes the existing transformer and does not increase the cost to configure more transformers, so the cost is low.

[0025] Additional aspects and advantages of the present disclosure will be made apparent from the following description of embodiments of the present disclosure, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 FIG. 1 shows a flowchart of a method for energy storage frequency modulation using an overload capacity of a transformer according to an embodiment of the present disclosure;

[0028] Figure 2 FIG. 2 shows a flowchart of a method for obtaining a target capacity according to an embodiment of the present disclosure;

[0029] Figure 3 FIG. 3 shows a block diagram of an energy storage frequency modulation system using an overload capacity of a transformer according to an embodiment of the present disclosure;

[0030] Figure 4 FIG. 4 is a block diagram of an energy storage frequency modulation device using an overload capacity of a transformer for implementing the method for energy storage frequency modulation using an overload capacity of a transformer according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] Example embodiments will be described in detail below with reference to the attached drawings. The description of the example embodiments is intended to apply to any example embodiments, unless specifically stated otherwise, and it should be understood that not all of the example embodiments described below relate to each other. Rather, they merely represent examples of devices and methods consistent with the example embodiments of the present disclosure, as detailed in the appended claims.

[0032] In the description of the present disclosure, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present description, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present description and the features of the different embodiments or examples, without contradiction.

[0033] In addition, the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited. It should also be understood that the term "and / or" used in the present disclosure means and includes any or all possible combinations of one or more associated listed items.

[0034] The embodiments of the present disclosure are described in detail below, examples of which are shown in the attached drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present disclosure, and cannot be understood as a limitation of the present disclosure.

[0035] The present disclosure provides a method and system for frequency modulation of energy storage using transformer overload capacity, mainly aiming to improve the power throughput during frequency modulation and reduce the cost. The method and system for frequency modulation of energy storage of the present disclosure are suitable for a molten salt energy storage system assisting a generator set to respond to AGC frequency modulation instructions. The AGC frequency modulation instructions have the characteristics of high power and short charging and discharging time, so the response process of the AGC frequency modulation instructions can be regarded as the normal periodic load of the molten salt energy storage system, that is, the temperature is higher or exceeds the rated current in a certain period of time in the periodic load, but it can be compensated by the lower ambient temperature or below the rated current in other time. From the perspective of thermal aging, it is equivalent to applying the rated load under the design environment temperature, thereby ensuring the safe, stable and efficient operation of the transformer. The method and system for frequency modulation of energy storage of the present disclosure regard the AGC frequency modulation instructions as the normal periodic load of the molten salt energy storage system, and use the normal overload capacity of the transformer to improve the regulation capacity of the molten salt energy storage system, so that the molten salt energy storage system can regulate the power system in a larger range (i.e. larger power) without increasing the transformer.

[0036] In the first embodiment, Figure 1 A flowchart of a method for frequency modulation of energy storage using transformer overload capacity provided by an embodiment of the present disclosure is shown. As Figure 1 shown, the method for frequency modulation of energy storage using transformer overload capacity comprises:

[0037] Step S11, obtaining historical AGC frequency modulation instructions received by a generator set to obtain the frequency of absolute values of the AGC frequency modulation instructions.

[0038] In step S11, the historical AGC frequency modulation instructions received by the generator set can be sent by a grid dispatching mechanism.

[0039] In step S11, the AGC frequency modulation instructions are divided into downward adjustment AGC instructions and downward adjustment AGC instructions. Therefore, the frequency of absolute values of the AGC frequency modulation instructions is counted based on the historical AGC frequency modulation instructions.

[0040] Step S12, obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system as the target capacity.

[0041] In step S12, the target capacity is obtained based on the frequency, which includes: forming a frequency histogram based on the frequency; and calculating the target capacity based on the power of the frequency peak of the frequency histogram. Wherein the target capacity is calculated based on the power of the frequency peak of the frequency histogram, which includes: judging whether the frequency histogram has a single peak feature or a double peak feature, if it has a single peak feature, the target capacity is obtained based on the power of the frequency peak; if it has a double peak feature, the maximum power of the power corresponding to the two frequency peaks is selected, and the target capacity is obtained based on the maximum power.

[0042] In the embodiment, if the frequency histogram has a single peak characteristic (the frequency histogram is a single peak type) in step S12, the power corresponding to the frequency peak is obtained by fitting the frequency histogram with a normal distribution. If the frequency histogram has a double peak characteristic (the frequency histogram is a double peak type), the power corresponding to the two frequency peaks is obtained by fitting the frequency histogram with a Gaussian mixture model.

[0043] If the frequency histogram is a single peak type, the power of the frequency peak is denoted as P1. If the frequency histogram is a double peak type, the two frequency peaks are a first frequency peak and a second frequency peak, the first power of the first frequency peak is denoted as P2, and the second power of the second frequency peak is denoted as P3. When the frequency histogram is a single peak type, the target capacity S is calculated by S = 2.4 x P1 x λ. Wherein λ is a power factor, λ = 1 MVA / MW. When the frequency histogram is a double peak type, if P3 > P2, the target capacity S is calculated by S = 1.2 x P3 x λ.

[0044] Figure 2 A flowchart of the method for obtaining the target capacity provided by the embodiment of the present disclosure is shown.

[0045] As shown in Figure 2 The method for obtaining the target capacity includes: forming a frequency histogram based on the frequency of the absolute value of the AGC frequency modulation instruction; determining whether the frequency histogram is a single peak type or a double peak type; if it is a single peak type, obtaining the power P1 of the frequency peak, and calculating the output target capacity S by S = 2.4 x P1 x λ; if it is a double peak type, obtaining the first power P2 of the first frequency peak and the second power P3 of the second frequency peak, and determining the size of the first power P2 and the second power P3; if P3 > P2, calculating the output target capacity S by S = 1.2 x P3 x λ, otherwise calculating the output target capacity S by S = 1.2 x P2 x λ.

[0046] In step S12, the rated capacity of the molten salt energy storage system is configured as the target capacity. The target capacity can be considered as the sum of the capacities of all distribution transformers of the molten salt energy storage system.

[0047] In step S13, when no AGC frequency modulation instruction is received, the molten salt energy storage system is controlled to operate normally at a set load rate.

[0048] In step S13, when no AGC frequency modulation instruction is received, the molten salt energy storage system does not participate in frequency modulation, and the molten salt energy storage system is controlled to operate normally at a set load rate. The set load rate is, for example, 75%. That is, when operating normally, the load rate of the distribution transformer of the molten salt energy storage system is 75%, and at this time the sum of the loads of all transformers of the molten salt energy storage system is 0.75S.

[0049] In step S13, when the molten salt energy storage system is normally operated according to the set load rate, the molten salt energy storage system transformer is also configured with an overcurrent protection, and the action current of the overcurrent protection is set to be 2 times of the rated current of the transformer. The actual current of the molten salt energy storage system transformer is detected in real time, and an alarm is given when the actual current exceeds the action current.

[0050] In step S13, when the molten salt energy storage system is normally operated according to the set load rate, the molten salt energy storage system transformer is also configured with an overcurrent protection, and the action current of the overcurrent protection is set to be 2 times of the rated current of the transformer. The actual current of the molten salt energy storage system transformer is detected in real time, and an alarm is given when the actual current exceeds the action current.

[0051] In step S14, when the AGC frequency modulation instruction is received, the maximum load rate of the molten salt energy storage system is determined based on the overload capacity of the molten salt energy storage system transformer, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency modulated based on the target regulation power.

[0052] In step S14, when the AGC frequency modulation instruction is received, considering that the AGC frequency modulation instruction has the distribution characteristics of large power and short charging and discharging time, the AGC frequency modulation instruction can be regarded as a normal periodic load of the molten salt energy storage system, and at this time, the overload capacity of the molten salt energy storage system transformer can be used to improve the power throughput without increasing the distribution transformer, that is, without additional investment cost. The overload capacity of the transformer is recorded in the existing 2021 version of the “Power Transformer Operation Regulations” and the “Distribution Transformer Operation Regulations”, and the overload capacity of the transformer refers to that the transformer can be operated at rated current all year round under rated operating conditions, and a certain overload capacity is allowed.

[0053] Specifically, in step S14, the maximum load rate of the molten salt energy storage system is determined based on the overload capacity of the molten salt energy storage system transformer. The maximum load rate of the molten salt energy storage system is, for example, 150%. That is, the transformer can bear a load of 1.5S at most.

[0054] In step S14, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, including: obtaining the maximum bearable power based on the maximum load rate and the rated capacity; obtaining the basic operation power based on the set load rate and the rated capacity; obtaining the target regulation power based on the maximum bearable power and the basic operation power. Taking the maximum load rate as 150% and the set load rate as 75% as an example, the maximum bearable load of the transformer (i.e. 1.5S load) is obtained based on the maximum load rate and the rated capacity, so as to obtain the maximum bearable power; the normal operation bearable load of the transformer (i.e. 0.75S load) is obtained based on the set load rate and the rated capacity, so as to obtain the basic operation power, the regulation load (i.e. 0.75S load) is obtained based on the difference between the maximum bearable load and the normal operation bearable load, and the target regulation power is obtained based on the difference between the maximum bearable power and the basic operation power. The molten salt energy storage system participates in frequency regulation according to the target regulation power, and the regulation capacity is the regulation load.

[0055] In step S14, since the AGC frequency regulation instruction is divided into the downward regulation AGC instruction and the upward regulation AGC instruction, the molten salt energy storage system participating in frequency regulation according to the target regulation power is divided into two cases, which are respectively:

[0056] When the generator set receives the downward regulation AGC frequency regulation instruction, the molten salt energy storage system needs to increase the transformer load. According to the normal overload capacity of the transformer, the transformer can bear 1.5S load at most, and the normal operation bearable load is 0.75S. The maximum positive regulation load that the molten salt energy storage system can respond to is 0.75S, and the molten salt energy storage system performs positive frequency regulation according to the target regulation power.

[0057] When the generator set receives the upward regulation AGC instruction, the molten salt energy storage system needs to reduce the transformer load. The transformer can bear 1.5S load at most, and the normal operation bearable load is 0.75S. The maximum positive regulation load that the molten salt energy storage system can respond to is 0.75S, and the molten salt energy storage system performs positive frequency regulation according to the target regulation power.

[0058] In the embodiment, when the frequency regulation response is received, the time of responding to the AGC frequency regulation instruction is negatively related to the environmental temperature, that is, the higher the environmental temperature, the shorter the time of responding to the frequency regulation instruction of the transformer overload. The time of responding to the AGC frequency regulation instruction is negatively related to the overload coefficient, that is, the greater the overload coefficient, the shorter the time of responding to the frequency regulation instruction of the transformer overload.

[0059] In the energy storage frequency modulation method using transformer overload capacity in the embodiments of the present disclosure, historical AGC frequency modulation instructions received by the generator set are obtained to obtain the frequency of the absolute value of the AGC frequency modulation instructions; the target capacity is obtained based on the frequency, and the rated capacity of the molten salt energy storage system is configured as the target capacity; when no AGC frequency modulation instruction is received, the molten salt energy storage system is controlled to normally operate according to the set load rate; when the AGC frequency modulation instruction is received, the maximum load rate of the molten salt energy storage system is determined based on the overload capacity of the transformer of the molten salt energy storage system, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency modulated based on the target regulation power. In this case, the AGC frequency modulation instruction is regarded as a normal periodic load of the molten salt energy storage system by taking advantage of the characteristics that the large power charging and discharging time of the AGC frequency modulation instruction is short, the target capacity is obtained based on the frequency of the AGC frequency modulation instruction as the rated capacity of the molten salt energy storage system, the maximum load rate of the molten salt energy storage system is determined by using the overload capacity of the transformer of the molten salt energy storage system, and the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity to frequency modulate the power system, thereby improving the power throughput during frequency modulation. In addition, the method of the present disclosure uses the existing transformer and does not increase the cost to configure more transformers, so the cost is low. Specifically, taking the maximum load rate of 150% and the set load rate of 75% as an example, the method of the present disclosure regards the AGC frequency modulation instruction as a normal periodic load of the molten salt energy storage system, and when normally operating, the load rate of the distribution transformer of the molten salt energy storage system is 75%. When responding to the AGC frequency modulation instruction, the transformer can bear 1.5S load at most according to the normal overload capacity of the transformer, thereby realizing a regulation range of ±0.75S. At the same time, the transformer overheat protection is configured to balance the heat accumulated during overload operation during low load operation, greatly improving the regulation range of the molten salt energy storage system, thereby obtaining more frequency modulation auxiliary service benefits, and having great application value. The distribution characteristics of the AGC instruction, i.e. the characteristics that the large power charging and discharging time is short, are ingeniously used to regard the AGC frequency modulation instruction as a normal periodic load of the molten salt energy storage system, and the overload capacity of the transformer is fully utilized to realize large-range regulation of the molten salt energy storage. Compared with the traditional control method, the problem that the power of the energy storage facility used for peak regulation is small and not suitable for frequency modulation auxiliary service can be solved without increasing investment, the regulation range of the molten salt energy storage system is greatly improved, more AGC frequency modulation instructions can be responded to, and more frequency modulation auxiliary benefits can be obtained.

[0060] The following is an embodiment of the system of the present disclosure, which can be used to execute the method embodiments of the present disclosure. For details not disclosed in the system embodiments of the present disclosure, please refer to the method embodiments of the present disclosure.

[0061] Please refer to Figure 3 , Figure 3A block diagram of the energy storage frequency modulation system using overload capacity of a transformer is shown. The energy storage frequency modulation system using overload capacity of a transformer can be implemented by software, hardware or a combination of both to become all or part of the system. The energy storage frequency modulation system using overload capacity of a transformer 10 includes an acquisition module 11, a calculation module 12, a control module 13 and a frequency modulation module 14, wherein:

[0062] The acquisition module 11 is configured to acquire historical AGC frequency modulation instructions received by a generator set to obtain the frequency of the absolute value of the AGC frequency modulation instructions.

[0063] The calculation module 12 is configured to obtain a target capacity based on the frequency, and configure the rated capacity of the molten salt energy storage system as the target capacity.

[0064] The control module 13 is configured to control the molten salt energy storage system to normally operate according to a set load rate when no AGC frequency modulation instruction is received.

[0065] The frequency modulation module 14 is configured to determine a maximum load rate of the molten salt energy storage system based on the overload capacity of the transformer of the molten salt energy storage system when the AGC frequency modulation instruction is received, obtain a target regulation power based on the maximum load rate, the set load rate and the rated capacity, and modulate the power system based on the target regulation power.

[0066] Optionally, the calculation module 12 is specifically configured to form a frequency histogram based on the frequency, determine whether the frequency histogram has a unimodal feature or a bimodal feature, obtain the target capacity based on the power corresponding to the frequency peak value if the frequency histogram has the unimodal feature, and select the maximum power from the powers corresponding to the two frequency peak values and obtain the target capacity based on the maximum power if the frequency histogram has the bimodal feature.

[0067] Optionally, if the frequency histogram has the unimodal feature, the power corresponding to the frequency peak value is obtained by fitting the frequency histogram with a normal distribution.

[0068] Optionally, if the frequency histogram has the bimodal feature, the powers corresponding to the two frequency peak values are obtained by fitting the frequency histogram with a Gaussian mixture model.

[0069] Optionally, the frequency modulation module 14 is specifically configured to obtain a maximum bearing power based on the maximum load rate and the rated capacity, obtain a basic operation power based on the set load rate and the rated capacity, and obtain the target regulation power based on the maximum bearing power and the basic operation power.

[0070] It should be noted that the energy storage frequency modulation system utilizing transformer overload capacity provided in the above embodiment, when executing the energy storage frequency modulation method utilizing transformer overload capacity, is only illustrated by the division of the above functional modules. In actual applications, the above functions can be distributed to different functional modules as needed, that is, the internal structure of the energy storage frequency modulation device utilizing transformer overload capacity can be divided into different functional modules to complete all or part of the functions described above. In addition, the energy storage frequency modulation system utilizing transformer overload capacity provided in the above embodiment and the energy storage frequency modulation method utilizing transformer overload capacity are based on the same concept. The implementation process is detailed in the method embodiment and will not be repeated here.

[0071] The serial numbers of the above-mentioned embodiments of the present disclosure are for description only and do not represent the advantages or disadvantages of the embodiments.

[0072] In the energy storage frequency modulation system utilizing the overload capacity of the transformer in the embodiments of the present disclosure, the acquisition module is configured to acquire historical AGC frequency modulation instructions received by the generator set to obtain the frequency of the absolute value of the AGC frequency modulation instructions; the calculation module is configured to obtain a target capacity based on the frequency, and configure the rated capacity of the molten salt energy storage system as the target capacity; the control module is configured to control the molten salt energy storage system to normally operate at a set load rate when no AGC frequency modulation instruction is received; and the frequency modulation module is configured to determine the maximum load rate of the molten salt energy storage system based on the overload capacity of the transformer of the molten salt energy storage system when the AGC frequency modulation instruction is received, obtain a target regulation power based on the maximum load rate, the set load rate and the rated capacity, and perform frequency modulation on the power system based on the target regulation power. In this case, the AGC frequency modulation instruction is regarded as a normal periodic load of the molten salt energy storage system by taking advantage of the characteristics that the large-power charging and discharging time of the AGC frequency modulation instruction is short, the target capacity is obtained based on the frequency of the AGC frequency modulation instruction, the rated capacity of the molten salt energy storage system is configured as the target capacity, the maximum load rate of the molten salt energy storage system is determined by utilizing the overload capacity of the transformer of the molten salt energy storage system, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency-modulated, thereby improving the power throughput during frequency modulation. In addition, the system of the present disclosure utilizes the existing transformer and does not increase the cost to configure more transformers, and therefore the cost is low. Specifically, taking the maximum load rate of 150% and the set load rate of 75% as an example, the AGC frequency modulation instruction is regarded as a normal periodic load of the molten salt energy storage system by the system of the present disclosure, the load rate of the distribution transformer of the molten salt energy storage system is 75% during normal operation, the transformer can bear a load of 1.5S at most according to the normal overload capacity of the transformer when responding to the AGC frequency modulation instruction, thereby realizing a regulation range of ±0.75S, and meanwhile, the transformer overheat protection is configured to balance the heat accumulated during overload operation, greatly improving the regulation range of the molten salt energy storage system, thereby obtaining more frequency modulation auxiliary service benefits, and having great application value. The distribution characteristics of the AGC instruction, i.e., the characteristics that the large-power charging and discharging time is short, are ingeniously utilized, the AGC frequency modulation instruction is regarded as a normal periodic load of the molten salt energy storage system, and the overload capacity of the transformer is fully utilized to realize large-range regulation of the molten salt energy storage. Compared with the traditional control system, the problem that the power of the energy storage facility used for peak regulation is small and not suitable for frequency modulation auxiliary service can be solved without increasing investment, the regulation range of the molten salt energy storage system is greatly improved, more AGC frequency modulation instructions can be responded to, and more frequency modulation auxiliary benefits can be obtained.

[0073] According to the embodiments of the present disclosure, the present disclosure further provides an energy storage frequency modulation device utilizing the overload capacity of a transformer, a readable storage medium and a computer program product.

[0074] Figure 4is a block diagram of a transformer overload capacity utilizing energy storage frequency modulation device for implementing the transformer overload capacity utilizing energy storage frequency modulation method of embodiments of the present disclosure. The transformer overload capacity utilizing energy storage frequency modulation device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The transformer overload capacity utilizing energy storage frequency modulation device can also represent various forms of mobile devices such as personal digital processors, cellular telephones, smart phones, wearable electronic devices, and other similar computing devices. The components shown in the present disclosure, the connections and relationships between the components, and the functions of the components are merely for example and are not intended to limit implementation of the present disclosure described and / or claimed in the present disclosure.

[0075] As shown in Figure 4 The transformer overload capacity utilizing energy storage frequency modulation device 20 includes a computing unit 21 that can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 22 or a computer program loaded from a storage unit 28 into a random access memory (RAM) 23. Various programs and data required for operation of the transformer overload capacity utilizing energy storage frequency modulation device 20 can also be stored in the RAM 23. The computing unit 21, the ROM 22, and the RAM 23 are connected to each other through a bus 24. An input / output (I / O) interface 25 is also connected to the bus 24.

[0076] Various components in the transformer overload capacity utilizing energy storage frequency modulation device 20 are connected to the I / O interface 25, including an input unit 26, such as a keyboard, a mouse, and the like; an output unit 27, such as various types of displays, speakers, and the like; the storage unit 28, such as a magnetic disk, an optical disk, and the like, which is communicatively connected to the computing unit 21; and a communication unit 29, such as a network card, a modem, a wireless communication transceiver, and the like. The communication unit 29 allows the transformer overload capacity utilizing energy storage frequency modulation device 20 to exchange information / data with other transformer overload capacity utilizing energy storage frequency modulation devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0077] The computing unit 21 can be various general and / or special purpose processing components with processing and computing capabilities. Some examples of the computing unit 21 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The computing unit 21 performs various methods and processes described above, such as the energy storage frequency regulation method utilizing transformer overload capacity. For example, in some embodiments, the energy storage frequency regulation method utilizing transformer overload capacity can be implemented as a computer software program tangibly embodied in a machine-readable medium, such as the storage unit 28. In some embodiments, part or all of the computer program can be loaded and / or installed onto the energy storage frequency regulation device 20 via the ROM 22 and / or the communication unit 29. When the computer program is loaded onto the RAM 23 and executed by the computing unit 21, one or more steps of the energy storage frequency regulation method utilizing transformer overload capacity described above can be performed. Alternatively, in other embodiments, the computing unit 21 can be configured to perform the energy storage frequency regulation method utilizing transformer overload capacity by any other appropriate means, such as by means of firmware.

[0078] Various implementations of the systems and techniques described above in this disclosure can be realized in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a programmable logic electronic device (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0079] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, produces the functions / operations specified in the flowcharts and / or the block diagrams. The program code can be entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine or server, or entirely on a remote machine or server.

[0080] In this disclosure, a machine readable medium can be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or energy storage frequency modulation device utilizing transformer overload capacity, or that can be utilized by or in connection with an instruction execution system, apparatus, or energy storage frequency modulation device utilizing transformer overload capacity to perform a process. A machine readable medium can be a machine readable signal medium or a machine readable storage medium. A machine readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or electronic device, or any suitable combination of the foregoing. More specific examples of a machine readable storage medium can include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0081] To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0082] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), the Internet, and a blockchain network.

[0083] The computer system can include clients and servers. This relationship can be. The servers are typically remote from the clients with the interactions typically occurring over the network. The relationship between client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The servers can be cloud servers, also known as cloud computing servers or cloud hosts, which are a host product in the cloud computing service system to solve the defects of large management difficulty and weak business scalability in traditional physical hosts and VPS services ("Virtual Private Server", or simply "VPS"). The servers can also be servers of a distributed system, or servers combined with a blockchain.

[0084] It should be understood that the various forms of flow shown above can be reordered, steps added or removed. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved, and the present disclosure is not limited herein.

[0085] The above detailed description does not constitute a limitation on the protection scope of the present disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for frequency modulation by energy storage using transformer overload capacity, characterized in that: include: Obtain the historical AGC frequency regulation instructions received by the generator set to obtain the frequency of the absolute value of the AGC frequency regulation instructions; forming a frequency histogram based on the frequencies; Determine whether the frequency histogram has a unimodal feature or a bimodal feature. If it has a unimodal feature, obtain the target capacity based on the power of the frequency peak; if it has a bimodal feature, select the maximum power of the powers corresponding to the two frequency peaks and obtain the target capacity based on the maximum power; as well as configuring the rated capacity of the molten salt energy storage system to the target capacity; When no AGC frequency modulation instruction is received, controlling the molten salt energy storage system to operate normally according to the set load rate; When an AGC frequency modulation instruction is received, the maximum load rate of the molten salt energy storage system is determined based on the overload capacity of the molten salt energy storage system transformer, the target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is frequency modulated based on the target regulation power.

2. The energy storage frequency modulation method using transformer overload capacity according to claim 1, characterized in that: The obtaining of the target regulated power based on the maximum load rate, the set load rate, and the rated capacity includes: Obtaining a maximum borne power based on the maximum load rate and the rated capacity; obtaining a basic operating power based on the set load rate and the rated capacity; A target adjustment power is obtained based on the maximum assumed power and the basic operating power.

3. The energy storage frequency modulation method using transformer overload capacity according to claim 1, characterized in that: If the frequency histogram has a single peak feature, the frequency histogram is fitted by a normal distribution to obtain the power corresponding to the frequency peak.

4. The energy storage frequency modulation method using transformer overload capacity according to claim 1, characterized in that: If the frequency histogram has a bimodal feature, the power corresponding to the two frequency peaks is obtained by fitting the frequency histogram using a Gaussian mixture model.

5. An energy storage frequency modulation system utilizing the overload capacity of a transformer, characterized in that: include: An acquisition module is used to acquire historical AGC frequency regulation instructions received by the generator set to obtain the frequency of the absolute value of the AGC frequency regulation instruction; a calculation module, configured to form a frequency histogram based on the frequency; determine whether the frequency histogram has a unimodal feature or a bimodal feature, and if it has a unimodal feature, obtain the target capacity based on the power of the frequency peak; if it has a bimodal feature, select the maximum power corresponding to the two frequency peaks, and obtain the target capacity based on the maximum power; and configuring the rated capacity of the molten salt energy storage system to a target capacity; A control module, configured to control the molten salt energy storage system to operate normally according to a set load rate when no AGC frequency modulation instruction is received; The frequency modulation module is used to determine the maximum load rate of the molten salt energy storage system based on the overload capacity of the molten salt energy storage system transformer when receiving the AGC frequency modulation instruction, obtain the target regulation power based on the maximum load rate, the set load rate and the rated capacity, and regulate the frequency of the power system based on the target regulation power.

6. The energy storage frequency modulation system utilizing the overload capacity of the transformer as claimed in claim 5, characterized in that: The frequency modulation module is specifically used for: The maximum assumed power is obtained based on the maximum load rate and the rated capacity; the basic operating power is obtained based on the set load rate and the rated capacity; and the target regulated power is obtained based on the maximum assumed power and the basic operating power.

7. An energy storage frequency modulation device utilizing the overload capacity of a transformer, characterized in that: include: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the energy storage frequency regulation method utilizing the overload capacity of the transformer as described in any one of claims 1-4.

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