CN115986777A - Energy storage frequency modulation method and system by using overload capacity of transformer - Google Patents

Abstract

The invention provides an energy storage frequency modulation method and system by utilizing overload capacity of a transformer, wherein the method comprises the steps of obtaining historical AGC frequency modulation instructions received by a generator set so as to obtain the frequency of absolute values 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 to the target capacity; when the AGC frequency modulation instruction is not received, controlling the molten salt energy storage system to normally operate according to a set load rate; when an AGC frequency modulation instruction is received, the maximum load rate of the fused salt energy storage system is determined based on the overload capacity of the transformer of the fused salt energy storage system, target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is subjected to frequency modulation based on the target regulation power. According to the method disclosed by the invention, the power throughput during frequency modulation can be improved, and the cost is lower.

Description

Energy storage frequency modulation method and system by using overload capacity of transformer

Technical Field

The disclosure belongs to the technical field of power system automation, and particularly relates to an energy storage frequency modulation method and system utilizing overload capacity of a transformer.

Background

China clearly points out in the 'Cogeneration management method' (revised energy [2016 ]) 617), and encourages thermoelectric generator set to implement deep peak regulation by measures such as heat storage and energy storage, and provides peak regulation compensation. With the further deepening of the reform of the electric power system in China, electric heat storage peak regulation facilities are added in the thermal power plant, the peak regulation capacity is increased, and economic compensation can be obtained by assisting market trading through peak regulation.

Although the demand of the power grid on the energy storage participation peak shaving is large, the income is low for the energy storage investment and is not enough to balance the acquisition cost of the energy storage facility. However, the energy storage facilities participating in peak shaving can participate in providing frequency modulation auxiliary services at the same time, and in a plurality of auxiliary services such as frequency modulation, peak shaving, standby, rotational inertia, climbing, phase modulation, stable control of a generator, rapid load shedding and the like, the benefit of the frequency modulation auxiliary services is the highest, so that the energy storage facilities for peak shaving begin to transform to the provision of the frequency modulation services.

However, the energy storage facility for peak shaving has the characteristics of small power and large energy, and if the frequency modulation service is converted, more distribution transformers need to be configured to improve the power throughput, so that the investment cost needs to be increased. Therefore, for the existing energy storage facilities, a frequency modulation method for improving the power throughput with lower cost is lacked in the prior art.

Disclosure of Invention

The present disclosure is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the energy storage frequency modulation method and system utilizing the overload capacity of the transformer are provided, and the main purpose is to improve the power throughput during frequency modulation and lower the cost.

According to an embodiment of a first aspect of the present disclosure, there is provided an energy storage frequency modulation method using a transformer overload capability, including:

acquiring a historical AGC frequency modulation instruction received by a generator set to acquire the frequency of an absolute value of the AGC frequency modulation instruction;

obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system to the target capacity;

when the AGC frequency modulation instruction is not received, controlling the molten salt energy storage system to normally operate according to a set load rate;

when an AGC frequency modulation instruction is received, determining the maximum load rate of a fused salt energy storage system based on the overload capacity of a transformer of the fused salt energy storage system, obtaining target adjusting power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of an electric power system based on the target adjusting power.

In one embodiment of the present disclosure, the obtaining the target capacity based on the frequency includes: forming a frequency histogram based on the frequency; and calculating the target capacity based on the power of the frequency peak value of the frequency histogram.

In an embodiment of the present disclosure, the calculating the target capacity based on the power of the frequency peak of the frequency histogram includes: judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining the target capacity based on the power of a frequency peak value; and if the target capacity has the double-peak characteristic, selecting the maximum power in the power corresponding to the two frequency peak values, and obtaining the target capacity based on the maximum power.

In one embodiment of the present disclosure, the obtaining the target regulated power based on the maximum load rate, the set load rate, and the rated capacity includes: obtaining a maximum assumed power based on the maximum load rate and the rated capacity; obtaining a base operating power based on the set load factor and the rated capacity; a target regulated power is obtained based on the maximum assumed power and the base operating power.

In an embodiment of the present disclosure, if the frequency histogram has a unimodal characteristic, the frequency histogram is fitted through a normal distribution to obtain a power corresponding to a frequency peak.

In an embodiment of the present disclosure, if the frequency histogram has a bimodal feature, the frequency histogram is fitted by a gaussian mixture model to obtain powers corresponding to two frequency peaks.

According to a second aspect of the embodiment of the present disclosure, there is also provided an energy storage frequency modulation system using a transformer overload capability, including:

the acquisition module is used for acquiring historical AGC frequency modulation instructions received by the generator set so as to acquire the frequency of absolute values of the AGC frequency modulation instructions;

the calculation module is used for obtaining a target capacity based on the frequency and configuring the rated capacity of the molten salt energy storage system to the target capacity;

the control module is used for controlling the molten salt energy storage system to normally operate according to a set load rate when the AGC frequency modulation instruction is not received;

the frequency modulation module is used for determining the maximum load rate of the fused salt energy storage system based on the overload capacity of the transformer of the fused salt energy storage system when receiving an AGC frequency modulation instruction, obtaining target regulation power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of the power system based on the target regulation power.

In an embodiment of the present disclosure, the calculation module is specifically configured to: forming a frequency histogram based on the frequency; judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining the target capacity based on the power of a frequency peak value; and if the target capacity has the double-peak characteristic, selecting the maximum power in the power corresponding to the two frequency peaks, and obtaining the target capacity based on the maximum power.

In an embodiment of the present disclosure, the frequency modulation module is specifically configured to: obtaining a maximum assumed power based on the maximum load rate and the rated capacity; obtaining a base operating power based on the set load factor and the rated capacity; a target regulated power is obtained based on the maximum assumed power and the base operating power.

According to an embodiment of the third aspect of the present disclosure, there is also provided an energy storage frequency modulation device using a transformer overload capability, including: at least one processor; and a memory communicatively coupled 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 to enable the at least one processor to perform the method for frequency modulation of energy storage using transformer overload capability as set forth in the embodiments of the first aspect of the present disclosure.

In one or more embodiments of the present disclosure, a historical AGC frequency modulation instruction received by a generator set is obtained to obtain a frequency of an absolute value of the AGC frequency modulation instruction; obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system to the target capacity; when the AGC frequency modulation instruction is not received, controlling the molten salt energy storage system to normally operate according to a set load rate; when an AGC frequency modulation instruction is received, the maximum load rate of the fused salt energy storage system is determined based on the overload capacity of the transformer of the fused salt energy storage system, target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is subjected to frequency modulation based on the target regulation power. Under the condition, the characteristic that the high-power charging and discharging time of the AGC frequency modulation instruction is short is utilized, the AGC frequency modulation instruction is taken as the normal periodic load of the molten salt energy storage system, the target capacity is obtained based on the frequency of the AGC frequency modulation instruction and is taken 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 utilizing the overload capacity of a transformer of the molten salt energy storage system, and the target adjusting power is obtained based on the maximum load rate, the set load rate and the rated capacity so as to modulate the frequency of the power system, so that the power throughput during frequency modulation is improved.

Additional aspects and advantages of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure.

Drawings

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

fig. 1 is a schematic flow chart illustrating an energy storage frequency modulation method using transformer overload capability according to an embodiment of the present disclosure;

fig. 2 is a schematic flowchart illustrating a method for obtaining a target capacity according to an embodiment of the present disclosure;

fig. 3 illustrates a block diagram of an energy storage frequency modulation system utilizing transformer overload capability provided by an embodiment of the present disclosure;

fig. 4 is a block diagram of an energy storage frequency modulation device utilizing transformer overload capability to implement the energy storage frequency modulation method utilizing transformer overload capability of the embodiments of the present disclosure.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with embodiments of the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the disclosed embodiments, as detailed in the appended claims.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present disclosure, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. It should also be understood that the term "and/or" as used in this disclosure refers to and encompasses any and all possible combinations of one or more of the associated listed items.

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and intended to be illustrative of the present disclosure, and should not be construed as limiting the present disclosure.

The invention provides an energy storage frequency modulation method and system by utilizing overload capacity of a transformer, and mainly aims to improve power throughput during frequency modulation and lower cost. The energy storage frequency modulation method and system are suitable for a molten salt energy storage system for assisting the generator set to respond to an AGC frequency modulation instruction. The AGC frequency modulation instruction has the characteristic of short charging and discharging time with high power, so the response process to the AGC frequency modulation instruction can be regarded as the normal periodic load of the molten salt energy storage system, namely the temperature is higher at a certain period of time in the periodic load or exceeds the rated current, but can be compensated by the lower ambient temperature at other times or lower than the rated current. From the thermal aging point of view, the transformer is equivalent to the rated load applied under the environment temperature adopted by design, thereby ensuring the safe, stable and efficient operation of the transformer. According to the energy storage frequency modulation method and system, under the condition that the AGC frequency modulation instruction is regarded as the normal periodic load of the molten salt energy storage system, the normal overload capacity of the transformer is utilized to improve the adjustment capacity of the molten salt energy storage system, so that the molten salt energy storage system can modulate the frequency of the power system in a wider range (namely, higher power) under the condition that the transformer is not increased.

In a first embodiment, fig. 1 shows a schematic flowchart of an energy storage frequency modulation method using overload capability of a transformer according to an embodiment of the present disclosure. As shown in fig. 1, the method for modulating frequency of stored energy by using overload capability of transformer includes:

and S11, acquiring historical AGC frequency modulation instructions received by the generator set to acquire the frequency of absolute values of the AGC frequency modulation instructions.

In step S11, the historical AGC fm commands received by the generator set may be sent by the grid dispatching authority.

In step S11, the AGC frequency modulation command is divided into an AGC command for downward adjustment and an AGC command for downward adjustment. Therefore, the frequency of the absolute value of the AGC frequency modulation instruction is counted based on the historical AGC frequency modulation instruction.

And S12, acquiring target capacity based on frequency, and configuring the rated capacity of the molten salt energy storage system to the target capacity.

In step S12, the target capacity is obtained based on the frequency, including: 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. The target capacity is obtained by calculating the power of the frequency peak value based on the frequency histogram, and the method comprises the following steps: judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining target capacity based on the power of a frequency peak value; and if the double-peak characteristic exists, selecting the maximum power in the power corresponding to the two frequency peaks, and obtaining the target capacity based on the maximum power.

In this embodiment, if the frequency histogram has a unimodal feature (the frequency histogram is unimodal), the power corresponding to the frequency peak is obtained by fitting the frequency histogram through normal distribution in step S12. If the frequency histogram has a bimodal characteristic (the frequency histogram is bimodal), fitting the frequency histogram through a Gaussian mixture model to obtain the power corresponding to two frequency peaks.

If the frequency histogram is a single-peak type, the power of the frequency peak is represented by P1, and if the frequency histogram is a double-peak type, the two frequency peaks are respectively a first frequency peak and a second frequency peak, the first power of the first frequency peak is represented by P2, and the second power of the second frequency peak is represented by P3. When the frequency histogram is a single-peak type, calculating by S =2.4 × P1 × λ to obtain a target capacity S; wherein λ is the power factor, λ =1MVA/MW. When P3 > P2, the frequency histogram is a bimodal type, the target capacity S is calculated by S =1.2 × P3 × λ.

Fig. 2 is a schematic flowchart illustrating a method for acquiring a target capacity according to an embodiment of the present disclosure.

As shown in fig. 2, the method for acquiring the target capacity includes: forming a frequency histogram based on the frequency of the absolute value of the AGC frequency modulation instruction; judging whether the frequency histogram is a single-peak type or a double-peak type; if the power P1 of the frequency peak value is obtained in a single-peak mode, calculating output target capacity S through S =2.4 xP 1 xlambda; if the power is a double-peak type, acquiring a first power P2 of a first frequency peak value and a second power P3 of a second frequency peak value, and judging the sizes of the first power P2 and the second power P3; if P3 > P2, the output target capacity S is calculated by S =1.2 × P3 × λ, otherwise the output target capacity S is calculated by S =1.2 × P2 × λ.

In step S12, the rated capacity of the molten salt energy storage system is configured to the target capacity. The target capacity may be considered to be the sum of the capacities of all distribution transformers of the molten salt energy storage system.

And S13, controlling the molten salt energy storage system to normally operate according to the set load rate when the AGC frequency modulation instruction is not received.

In step S13, when the AGC frequency modulation instruction is not received, the molten salt energy storage system does not participate in the frequency modulation, and the molten salt energy storage system is controlled to normally operate according to the set load factor. The set load factor is, for example, 75%. Namely, during normal operation, the load factor of the distribution transformer of the molten salt energy storage system is 75%, and the sum of the loads of all transformers of the molten salt energy storage system is 0.75S.

In step S13, when the molten salt energy storage system normally operates according to the set load factor, the molten salt energy storage system transformer is further configured with overcurrent protection, and the operating current of the overcurrent protection is set to be 2 times of the rated current of the transformer. And detecting the actual current of the transformer of the fused salt energy storage system in real time, and alarming when the actual current exceeds the action current.

In step S13, when the molten salt energy storage system normally operates according to the set load factor, the molten salt energy storage system transformer is further provided with overheat protection, so as to ensure that the heat accumulated during overload operation can be balanced during low-load operation. When the heat is not balanced, an alarm is given.

And S14, 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 target regulation power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of the power system based on the target regulation power.

In step S14, when the AGC frequency modulation instruction is received, considering that the AGC frequency modulation instruction has a distribution characteristic of a large power and a short charging and discharging time, the AGC frequency modulation instruction may be regarded as a normal periodic load of the molten salt energy storage system, and at this time, the overload capability of the transformer of the molten salt energy storage system may be utilized to improve the power throughput without increasing the distribution transformer, i.e., without increasing the investment cost additionally. The explanation of the overload capability of the transformer is described in the existing power transformer operating regulation and distribution transformer operating regulation, which are newly released in 2021 years, and the overload capability of the transformer means that the transformer can operate at rated current all year around under rated service conditions, and a certain overload capability is allowed.

Specifically, in step S14, the maximum load rate of the molten salt energy storage system is determined based on the overload capability of the molten salt energy storage system transformer. The maximum load factor of the molten salt energy storage system is, for example, 150%. I.e. the transformer can bear a load of 1.5S at maximum.

In step S14, a target regulated power is obtained based on the maximum load factor, the set load factor, and the rated capacity, including: obtaining the maximum borne power based on the maximum load rate and the rated capacity; obtaining basic operation power based on the set load rate and the rated capacity; the target regulated power is obtained based on the maximum assumed power and the base operating power. Taking the maximum load rate as 150% and the set load rate as 75% as an example, the maximum bearable load (i.e. the load of 1.5S) of the transformer is obtained based on the maximum load rate and the rated capacity, so that the maximum bearable power is obtained; the normal operation borne load (namely the load of 0.75S) of the transformer is obtained based on the set load rate and the rated capacity, so that the basic operation power is obtained, the regulation load (namely the load of 0.75S) is obtained based on the difference value of the maximum bearable load and the normal operation borne load, and the target regulation power is obtained based on the difference value of the maximum borne power and the basic operation power. The molten salt energy storage system participates in frequency modulation according to target adjusting power, and the adjusting capacity of the molten salt energy storage system is load adjustment.

In step S14, since the AGC frequency modulation instruction is divided into an AGC instruction for downward adjustment and an AGC instruction for downward adjustment, the molten salt energy storage system is divided into 2 cases according to the target adjustment power participating in frequency modulation, which are:

when the generator set receives an AGC frequency modulation instruction which is adjusted downwards, the load of the transformer is increased by the fused salt energy storage system, the maximum load of the transformer can bear 1.5S according to the normal overload capacity of the transformer, the load of 0.75S borne by the transformer in normal operation is removed, the maximum response negative adjustment load of the fused salt energy storage system is 0.75S, and the fused salt energy storage system performs negative frequency modulation according to target adjustment power;

when the generator set receives an AGC instruction of upward adjustment, the load of the transformer is reduced by the molten salt energy storage system, the maximum load of the transformer can bear 1.5S, the load of 0.75S borne by the transformer in normal operation is removed, the maximum responsive forward adjustment load of the molten salt energy storage system is 0.75S, and the molten salt energy storage system performs forward frequency modulation according to target adjustment power;

in this embodiment, when receiving the AGC frequency modulation command to perform the frequency modulation response, the time for responding to the AGC frequency modulation command is inversely related to the ambient temperature, that is, the higher the ambient temperature is, the shorter the time for the transformer overload to respond to the frequency modulation command is. The time for responding to the AGC frequency modulation command is inversely related to the overload coefficient, namely the larger the overload coefficient is, the shorter the time for the transformer to overload and respond to the frequency modulation command is.

In the energy storage frequency modulation method utilizing the overload capacity of the transformer, a historical AGC frequency modulation instruction received by a generator set is obtained so as to obtain the frequency of the absolute value of the AGC frequency modulation instruction; obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system to the target capacity; when the AGC frequency modulation instruction is not received, controlling the molten salt energy storage system to normally operate according to a set load rate; when an AGC frequency modulation instruction is received, the maximum load rate of the fused salt energy storage system is determined based on the overload capacity of the transformer of the fused salt energy storage system, target regulation power is obtained based on the maximum load rate, the set load rate and the rated capacity, and the power system is subjected to frequency modulation based on the target regulation power. Under the condition, the characteristic that the high-power charging and discharging time of the AGC frequency modulation instruction is short is utilized, the AGC frequency modulation instruction is taken as the normal periodic load of the molten salt energy storage system, the target capacity is obtained based on the frequency of the AGC frequency modulation instruction and is taken 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 utilizing the overload capacity of a transformer of the molten salt energy storage system, and the target adjusting power is obtained based on the maximum load rate, the set load rate and the rated capacity so as to modulate the frequency of the power system, so that the power throughput during frequency modulation is improved. Specifically, taking the maximum load rate as 150% and the set load rate as 75% as an example, the method disclosed by the invention considers the AGC frequency modulation command as a normal periodic load of the molten salt energy storage system, and when the molten salt energy storage system operates normally, the load rate of a distribution transformer of the molten salt energy storage system is 75%, and when the AGC frequency modulation command is responded, the transformer can bear the load of 1.5S at most according to the normal overload capacity of the transformer, so that the adjustment range of ± 0.75S is realized, and meanwhile, the transformer overheating protection is configured, so that the heat accumulated during overload operation is balanced during low-load operation, and the adjustment range of the molten salt energy storage system is greatly improved, so that more frequency modulation auxiliary service benefits are obtained, and the method has a higher application value, and skillfully utilizes the distribution characteristics of the AGC command, namely the characteristic of short high-power charge and discharge time, to consider the AGC frequency modulation command as the normal periodic load of the molten salt energy storage system, and fully utilizes the overload capacity of the transformer, so as to realize the large-range adjustment of molten salt energy storage. Compared with the traditional control method, the method can solve the problems that the energy storage facility for peak shaving is low in power and is not suitable for frequency modulation auxiliary service under the condition that investment is not increased, greatly improves the adjusting range of the molten salt energy storage system, can respond to more AGC frequency modulation instructions, and ensures that more frequency modulation auxiliary benefits are obtained.

The following are embodiments of the disclosed system that may be used to perform embodiments of the disclosed method. For details not disclosed in the embodiments of the system of the present disclosure, refer to the embodiments of the method of the present disclosure.

Referring to fig. 3, fig. 3 is a block diagram illustrating an energy storage frequency modulation system using transformer overload capability according to an embodiment of the present disclosure. The energy storage frequency modulation system utilizing the overload capacity of the transformer can be realized into all or part of the system through software, hardware or a combination of the software and the hardware. The energy storage frequency modulation system 10 utilizing the overload capacity of the transformer comprises an acquisition module 11, a calculation module 12, a control module 13 and a frequency modulation module 14, wherein:

the acquisition module 11 is configured to acquire a historical AGC frequency modulation instruction received by the generator set to obtain a frequency of an absolute value of the AGC frequency modulation instruction;

the calculation module 12 is used for obtaining a target capacity based on the frequency and configuring the rated capacity of the molten salt energy storage system to the target capacity;

the control module 13 is used for controlling the molten salt energy storage system to normally operate according to a set load rate when the AGC frequency modulation instruction is not received;

and the frequency modulation module 14 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 capability of a transformer of the molten salt energy storage system, obtain a target adjustment power based on the maximum load rate, a set load rate, and a rated capacity, and modulate the frequency of the power system based on the target adjustment power.

Optionally, the calculating module 12 is specifically configured to: forming a frequency histogram based on the frequency; judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining target capacity based on the power of a frequency peak value; and if the double-peak characteristic exists, selecting the maximum power in the power corresponding to the two frequency peaks, and obtaining the target capacity based on the maximum power.

Optionally, if the frequency histogram has a unimodal characteristic, fitting the frequency histogram through normal distribution to obtain power corresponding to the frequency peak.

Optionally, if the frequency histogram has a bimodal feature, fitting the frequency histogram through a gaussian mixture model to obtain powers corresponding to two frequency peaks.

Optionally, the frequency modulation module 14 is specifically configured to: obtaining the maximum borne power based on the maximum load rate and the rated capacity; obtaining basic operation power based on the set load rate and the rated capacity; the target regulated power is obtained based on the maximum assumed power and the base operating power.

It should be noted that, when the energy storage frequency modulation system using the overload capability of the transformer provided in the above embodiment executes the energy storage frequency modulation method using the overload capability of the transformer, only the division of the above functional modules is exemplified, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the energy storage frequency modulation device using the overload capability of the transformer is divided into different functional modules, so as to complete all or part of the above described functions. In addition, the energy storage frequency modulation system using the overload capability of the transformer and the energy storage frequency modulation method using the overload capability of the transformer provided by the above embodiments belong to the same concept, and details of the implementation process are shown in the method embodiments, which are not described herein again.

The above-mentioned serial numbers of the embodiments of the present disclosure are merely for description and do not represent the merits of the embodiments.

In the energy storage frequency modulation system utilizing the overload capacity of the transformer, the acquisition module is used for acquiring historical AGC frequency modulation instructions received by the generator set so as to acquire the frequency of the absolute value of the AGC frequency modulation instructions; the calculation module is used for obtaining a target capacity based on the frequency and configuring the rated capacity of the molten salt energy storage system to the target capacity; the control module is used for controlling the molten salt energy storage system to normally operate according to a set load rate when the AGC frequency modulation instruction is not received; the frequency modulation module is used for determining the maximum load rate of the fused salt energy storage system based on the overload capacity of the transformer of the fused salt energy storage system when receiving an AGC frequency modulation instruction, obtaining target regulation power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of the power system based on the target regulation power. Under the condition, the characteristic that the high-power charging and discharging time of the AGC frequency modulation instruction is short is utilized, the AGC frequency modulation instruction is taken as the normal periodic load of the molten salt energy storage system, the target capacity is obtained based on the frequency of the AGC frequency modulation instruction and is taken 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 utilizing the overload capacity of a transformer of the molten salt energy storage system, and the target adjusting power is obtained based on the maximum load rate, the set load rate and the rated capacity so as to modulate the frequency of the power system, so that the power throughput during frequency modulation is improved. Specifically, taking the maximum load rate as 150% and the set load rate as 75% as an example, the system disclosed by the invention regards the AGC frequency modulation instruction as the normal periodic load of the molten salt energy storage system, when the system is in normal operation, the load rate of the distribution transformer of the molten salt energy storage system is 75%, and when the AGC frequency modulation instruction is responded, the transformer can bear the load of 1.5S to the maximum according to the normal overload capacity of the transformer, so that the adjustment range of ± 0.75S is realized, meanwhile, the transformer overheating protection is configured, the heat accumulated during overload operation is balanced during low-load operation, and the adjustment range of the molten salt energy storage system is greatly improved, so that more frequency modulation auxiliary service benefits are obtained, and the system has a larger application value, and skillfully utilizes the distribution characteristics of the AGC instruction, namely the characteristic of short high-power charge-discharge time, regards the AGC frequency modulation instruction as the normal periodic load of the molten salt energy storage system, fully utilizes the overload capacity of the transformer, and realizes the large-range adjustment of the molten salt energy storage. Compared with the traditional control system, the method can solve the problems that the energy storage facility for peak shaving is low in power and is not suitable for frequency modulation auxiliary service under the condition that investment is not increased, greatly improves the adjusting range of the molten salt energy storage system, can respond to more AGC frequency modulation instructions, and ensures that more frequency modulation auxiliary benefits are obtained.

According to embodiments of the present disclosure, there is also provided an energy storage frequency modulation device, a readable storage medium and a computer program product that utilize transformer overload capability.

Fig. 4 is a block diagram of an energy storage frequency modulation device utilizing transformer overload capability to implement the energy storage frequency modulation method utilizing transformer overload capability of the embodiments of the present disclosure. Energy storage frequency modulation devices that utilize transformer overload capabilities are intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The energy storage fm device utilizing transformer overload capabilities may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable electronics, and other similar computing devices. The components shown in the present disclosure, the connections and relationships of the components, and the functions of the components, are meant to be examples only, and are not meant to limit implementations of the present disclosure described and/or claimed in the present disclosure.

As shown in fig. 4, the energy storage frequency modulation device 20 utilizing the transformer overload capability includes a calculation unit 21 which 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. In the RAM 23, various programs and data required for the operation of the energy storage frequency modulation device 20 utilizing the overload capability of the transformer can also be stored. The calculation unit 21, the ROM22, and the RAM 23 are connected to each other via a bus 24. An input/output (I/O) interface 25 is also connected to bus 24.

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

The computing unit 21 may be a variety of general and/or special purpose processing components having 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 dedicated Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, and so forth. The calculation unit 21 performs the various methods and processes described above, for example performing an energy storage frequency modulation method that exploits the transformer overload capability. For example, in some embodiments, the energy storage frequency modulation method that takes advantage of the transformer overload capability may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as storage unit 28. In some embodiments, part or all of the computer program may be loaded and/or installed onto the energy storage frequency modulation device 20 utilizing the transformer overload capability via the ROM22 and/or the communication unit 29. When the computer program is loaded into the RAM 23 and executed by the computing unit 21, one or more steps of the above described method of energy storage frequency modulation using transformer overload capability may be performed. Alternatively, in other embodiments, the computing unit 21 may be configured to perform the energy storage frequency modulation method using the transformer overload capability in any other suitable manner (e.g., by means of firmware).

Various implementations of the systems and techniques described above in this disclosure may be implemented in digital electronic circuitry, integrated circuitry, field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), system on a chip (SOCs), load programmable logic electronic (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, receiving data and instructions from, and transmitting data and instructions to, a storage system, at least one input device, and at least one output device.

Program code for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the present disclosure, a machine-readable medium may be a tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or energy storage frequency modulation device that utilizes transformer overload capabilities. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an 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 would include an electrical connection based on one or more wires, a portable computer diskette, 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 compact disc read-only memory (CD-ROM), an optical storage electronic device, a magnetic storage electronic device, or any suitable combination of the foregoing.

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 a user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which a user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with a user; 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.

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: local Area Networks (LANs), wide Area Networks (WANs), the internet, and blockchain networks.

The computer system may include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The Server can be a cloud Server, also called a cloud computing Server or a cloud host, and is a host product in a cloud computing service system, so as to solve the defects of high management difficulty and weak service expansibility in the traditional physical host and VPS service ("Virtual Private Server", or simply "VPS"). The server may also be a server of a distributed system, or a server incorporating a blockchain.

It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present disclosure may be executed in parallel or sequentially or in different orders, and the present disclosure is not limited thereto as long as the desired results of the technical solutions of the present disclosure can be achieved.

The above detailed description should not be construed as limiting the scope of the disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims (10)

1. An energy storage frequency modulation method utilizing overload capacity of a transformer is characterized by comprising the following steps:

acquiring a historical AGC frequency modulation instruction received by a generator set to acquire the frequency of an absolute value of the AGC frequency modulation instruction;

obtaining a target capacity based on the frequency, and configuring the rated capacity of the molten salt energy storage system to the target capacity;

when the AGC frequency modulation instruction is not received, controlling the molten salt energy storage system to normally operate according to a set load factor;

when an AGC frequency modulation instruction is received, determining the maximum load rate of a fused salt energy storage system based on the overload capacity of a transformer of the fused salt energy storage system, obtaining target adjusting power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of an electric power system based on the target adjusting power.

2. The method for frequency modulation with energy storage according to claim 1, wherein said obtaining a target capacity based on said frequency comprises:

forming a frequency histogram based on the frequency;

and calculating the target capacity based on the power of the frequency peak value of the frequency histogram.

3. The method according to claim 2, wherein the calculating the target capacity based on the power of the frequency peak of the frequency histogram comprises:

judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining the target capacity based on the power of a frequency peak value; and if the target capacity has the double-peak characteristic, selecting the maximum power in the power corresponding to the two frequency peaks, and obtaining the target capacity based on the maximum power.

4. A method of frequency modulation according to claim 3 wherein said deriving a target regulated power based on said maximum load rate, said set load rate and said rated capacity comprises:

obtaining a maximum assumed power based on the maximum load rate and the rated capacity;

obtaining a base operating power based on the set load factor and the rated capacity;

a target regulated power is obtained based on the maximum assumed power and the base operating power.

5. The method according to claim 3, wherein if the frequency histogram has a unimodal characteristic, the power corresponding to the frequency peak is obtained by fitting the frequency histogram through normal distribution.

6. The method according to claim 3, wherein if the frequency histogram has a bimodal characteristic, the power corresponding to two frequency peaks is obtained by fitting the frequency histogram through a Gaussian mixture model.

7. An energy storage frequency modulation system using overload capacity of a transformer, comprising:

the acquisition module is used for acquiring historical AGC frequency modulation instructions received by the generator set so as to acquire the frequency of absolute values of the AGC frequency modulation instructions;

the calculation module is used for obtaining a target capacity based on the frequency and configuring the rated capacity of the molten salt energy storage system to the target capacity;

the control module is used for controlling the molten salt energy storage system to normally operate according to a set load rate when the AGC frequency modulation instruction is not received;

the frequency modulation module is used for determining the maximum load rate of the fused salt energy storage system based on the overload capacity of the transformer of the fused salt energy storage system when receiving an AGC frequency modulation instruction, obtaining target regulation power based on the maximum load rate, the set load rate and the rated capacity, and modulating the frequency of the power system based on the target regulation power.

8. The system according to claim 7, wherein the computing module is specifically configured to:

forming a frequency histogram based on the frequency; judging whether the frequency histogram has a unimodal characteristic or a bimodal characteristic, and if the frequency histogram has the unimodal characteristic, obtaining the target capacity based on the power of a frequency peak value; and if the target capacity has the double-peak characteristic, selecting the maximum power in the power corresponding to the two frequency peak values, and obtaining the target capacity based on the maximum power.

9. The system according to claim 8, wherein the frequency modulation module is specifically configured to:

obtaining a maximum assumed power based on the maximum load rate and the rated capacity; obtaining a basic operation power based on the set load factor and the rated capacity; a target regulated power is obtained based on the maximum assumed power and the base operating power.

10. An energy storage frequency modulation device utilizing transformer overload capability, comprising: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of energy storage frequency modulation using transformer overload capability of any one of claims 1 to 6.

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