Inertia supporting capacity allocation system of multi-source system

Abstract

The utility model relates to the technical field of electric power systems, in particular to an inertia supporting capacity allocation system of a multi-source system, which comprises a photovoltaic inertia calculator, a fan inertia calculator, a traditional unit inertia calculator, an energy storage inertia calculator and an inertia distributor. And the inertia distributor is used for distributing the inertia demand of the alternating current system according to the inertia supporting capacity of the photovoltaic power supply, the inertia supporting capacity of the fan power supply, the inertia supporting capacity of the traditional unit and the inertia supporting capacity of the energy storage power supply. According to the utility model, inertia supporting capabilities of a photovoltaic power supply, a fan power supply, a traditional unit and an energy storage power supply are respectively obtained through the photovoltaic inertia calculator, the fan inertia calculator, the traditional unit inertia calculator and the energy storage inertia calculator; the inertia demand of the alternating current system is distributed through the inertia distributor, and effective allocation of the inertia supporting capacity of the multi-source system is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electric power system, concretely relates to a kind of inertia support ability deployment system of multi-source system. BACKGROUND

[0002] With the proposal of double carbon target, the development of large-scale new energy base accelerates, and countries around the world are committed to developing new energy represented by wind and light. The output of wind turbine and photovoltaic unit is largely affected by weather, and the power generation output has large random fluctuations, which often causes phenomena such as "abandoned wind" and "abandoned light" on the power generation side. Therefore, in order to avoid the occurrence of this phenomenon, it is necessary to study it, so as to become a high-quality frequency modulation resource, relieve the frequency modulation pressure of traditional hydro and thermal power plants, and accelerate the dynamic response performance of system frequency modulation.

[0003] At present, the output power of each unit is allocated in proportion according to the adjustable capacity in the secondary frequency modulation engineering field, which is called proportional allocation, but this strategy cannot meet the optimal control demand of the system. In addition, most of the current research on the participation of wind and light new energy in frequency modulation mainly focuses on the design of controller and the control strategy of wind farm and photovoltaic power station itself, and less research on the cooperative control between wind and light new energy and other frequency modulation resources.

[0004] In recent years, in order to make the new energy system also have the characteristics of inertia and damping, scholars found that virtual synchronous machine control can simulate the advantages of inertia and damping of traditional power system. At the same time, it can realize frequency modulation, voltage regulation, power distribution and other functions, which greatly improves the stability of the system. At present, the microgrid system is generally connected in parallel with multiple units, but if the line impedance and equivalent output impedance values between each VSG are different, there will be circulating current and difficulty in dividing the reactive power, which reduces the stability of the system and damages the power electronic devices.

[0005] At present, how to effectively deploy the inertia support capacity of multi-source system is a research direction. Utility model content

[0006] (I) Utility model purpose

[0007] The utility model aims to provide a kind of inertia support capacity deployment system of multi-source system, which can effectively adjust the inertia support capacity of multi-source system.

[0008] (II) Technical scheme

[0009] In order to solve the above problems, the utility model provides a kind of inertia support ability deployment system of multi-source system, the multi-source system includes: photovoltaic power supply, fan power supply, traditional unit and energy storage power supply;Photovoltaic power supply, fan power supply, traditional unit and energy storage power supply are connected with alternating current system respectively;

[0010] The inertia support ability deployment system includes: photovoltaic inertia calculator, fan inertia calculator, traditional unit inertia calculator, energy storage inertia calculator and inertia distributor;

[0011] The inertia distributor is connected with the alternating current system, photovoltaic inertia calculator, fan inertia calculator, traditional unit inertia calculator and energy storage inertia calculator respectively;

[0012] The photovoltaic inertia calculator is connected with the photovoltaic power supply, and is used to calculate the inertia support ability of photovoltaic power supply;

[0013] The fan inertia calculator is connected with the fan power supply, and is used to calculate the inertia support ability of fan power supply;

[0014] The traditional unit inertia calculator is connected with the traditional unit, and is used to calculate the inertia support ability of traditional unit;

[0015] The energy storage inertia calculator is connected with the energy storage power supply, and is used to calculate the inertia support ability of energy storage power supply;

[0016] The inertia distributor is used to distribute the inertia demand of alternating current system according to the inertia support ability of photovoltaic power supply, the inertia support ability of fan power supply, the inertia support ability of traditional unit and the inertia support ability of energy storage power supply.

[0017] In another aspect of the utility model, preferably, the photovoltaic inertia calculator includes photovoltaic loss calculation unit;

[0018] The photovoltaic loss calculation unit is used to calculate the first loss to the alternating current system when photovoltaic power supply outputs maximum power.

[0019] In another aspect of the utility model, preferably, the fan inertia calculator includes fan loss calculation unit;

[0020] The fan loss calculation unit is used to calculate the second loss to the alternating current system when fan power supply outputs maximum power.

[0021] In another aspect of the utility model, preferably, the traditional unit inertia calculator includes traditional unit loss calculation unit;

[0022] The traditional unit loss calculation unit is used to calculate the third loss to the alternating current system when traditional unit outputs maximum power.

[0023] In another aspect of the utility model, preferably, the energy storage inertia calculator includes an energy storage loss calculation unit.

[0024] The energy storage loss calculation unit is used for calculating a fourth loss of the energy storage type power supply to the AC system when the energy storage type power supply outputs maximum power.

[0025] In another aspect of the utility model, preferably, the inertia distributor includes a sorting unit and a distribution unit.

[0026] The sorting unit sorts the first loss, the second loss, the third loss and the fourth loss according to the ascending order rule.

[0027] The distribution unit distributes the inertia of the photovoltaic type power supply, the fan type power supply, the traditional unit and the energy storage type power supply according to the sorting result of the sorting unit.

[0028] In another aspect of the utility model, preferably, the photovoltaic inertia calculator includes a photovoltaic direction selection unit; the photovoltaic direction selection unit determines the inertia direction of the photovoltaic type power supply according to the frequency change difference of the AC system.

[0029] In another aspect of the utility model, preferably, the fan inertia calculator includes a fan inertia selection unit.

[0030] The fan inertia selection unit determines the inertia of the fan type power supply according to the rotating speed of the fan type power supply.

[0031] In another aspect of the utility model, preferably, the traditional unit inertia calculator includes a traditional unit inertia selection unit; the traditional unit inertia selection unit determines the inertia of the traditional unit according to the rotating speed of the traditional unit.

[0032] In another aspect of the utility model, preferably, the energy storage inertia calculator includes an energy storage inertia selection unit.

[0033] The energy storage inertia selection unit determines the inertia of the energy storage type power supply according to the remaining power and the charging and discharging state of the energy storage type power supply.

[0034] (Three) beneficial effects

[0035] The above technical scheme of the utility model has the following beneficial technical effects:

[0036] The utility model obtains the inertia support ability of the photovoltaic type power supply, the fan type power supply, the traditional unit and the energy storage type power supply through the photovoltaic inertia calculator, the fan inertia calculator, the traditional unit inertia calculator and the energy storage inertia calculator respectively; the inertia demand of the AC system is distributed through the inertia distributor, and the effective distribution of the inertia support ability of the multi-source system is realized. DRAWINGS

[0037] Figure 1 is a whole structure schematic diagram of an embodiment of the present application;

[0038] Figure 2 is a typical configuration schematic diagram of prior art new energy station;

[0039] Figure 3 is a photovoltaic inertia calculator schematic diagram of an embodiment of the present application;

[0040] Figure 4 is a fan inertia calculator schematic diagram of an embodiment of the present application;

[0041] Figure 5 is a traditional unit inertia calculator schematic diagram of an embodiment of the present application;

[0042] Figure 6 is a energy storage inertia calculator schematic diagram of an embodiment of the present application;

[0043] Figure 7 is a sorting unit and distribution unit schematic diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below with specific embodiments and with reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0045] In the drawings, the structure schematic diagram according to the embodiment of the present application is shown. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and certain details can be omitted. The shape of various regions, layers and their relative size, position relationship shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and the skilled person in the art can additionally design regions / layers with different shapes, sizes, relative positions according to actual needs.

[0046] Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor fall within the scope of protection of the present application.

[0047] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0048] The utility model will be described in more detail below with reference to the drawings. In each drawing, the same elements are denoted by similar reference signs. For the sake of clarity, the various parts in the drawings are not drawn to scale.

[0049] Embodiment one

[0050] An inertia support capacity deployment system of a multi-source system, Figure 1 is the overall structure schematic diagram of one embodiment of the utility model; Figure 2 is the typical configuration schematic diagram of prior art new energy station; as Figure 1 and Figure 2 The new energy station includes an alternating current system, and the multi-source system includes photovoltaic power supply, fan power supply, traditional unit and energy storage power supply; the photovoltaic power supply, fan power supply, traditional unit and energy storage power supply are connected with the alternating current system respectively;

[0051] The inertia support capacity deployment system includes a photovoltaic inertia calculator, a fan inertia calculator, a traditional unit inertia calculator, an energy storage inertia calculator and an inertia distributor;

[0052] The inertia distributor is connected with the alternating current system, photovoltaic inertia calculator, fan inertia calculator, traditional unit inertia calculator and energy storage inertia calculator respectively;

[0053] The photovoltaic inertia calculator is connected with the photovoltaic power supply and is used for calculating the inertia support capacity of the photovoltaic power supply; the photovoltaic inertia calculator is directly connected with the photovoltaic power supply, and the output power, voltage, current and other key parameters of the photovoltaic power supply are collected in real time.Based on the collected data, the inertia support capacity of the photovoltaic power supply is calculated.

[0054] The fan inertia calculator is connected with the fan power supply and is used for calculating the inertia support capacity of the fan power supply; the fan inertia calculator is connected with the fan power supply, and the rotating speed, output power, wind speed and other parameters of the fan are acquired in real time.According to the physical characteristics and control strategy of the fan, the inertia support capacity of the fan under the grid disturbance is calculated.

[0055] The traditional unit inertia calculator is connected with the traditional unit and is used for calculating the inertia support capacity of the traditional unit; the traditional unit inertia calculator is connected with the traditional unit (such as coal-fired, gas or hydroelectric generating set), and the operating state, output power, rotating speed and other key information of the traditional unit are acquired.The mechanical inertia and control strategy of the traditional unit are utilized to calculate the inertia support capacity of the traditional unit under the grid disturbance.

[0056] The energy storage inertia calculator is connected with the energy storage power supply, and is used for calculating inertia support capability of the energy storage power supply; the energy storage inertia calculator is connected with the energy storage power supply (such as a battery energy storage system, a pumped storage power station and the like), and real-time parameters such as a charge-discharge state and a residual capacity of the energy storage system are obtained. According to a control strategy and a response speed of the energy storage system, the inertia support capability of the energy storage system under grid disturbance is calculated.

[0057] The inertia distributor is used for distributing inertia demand of the alternating current system according to the inertia support capability of the photovoltaic power supply, the inertia support capability of the fan power supply, the inertia support capability of the traditional unit and the inertia support capability of the energy storage power supply. The inertia distributor receives data from the inertia calculators, and integrates to form a complete inertia support capability atlas. According to the inertia demand of the alternating current system and the inertia support capability of each power supply, an optimal inertia distribution scheme is formulated. The distribution scheme is converted into specific control instructions, and is issued to each power supply for execution.

[0058] Further, in the embodiment, the photovoltaic inertia calculator comprises a photovoltaic loss calculation unit; the photovoltaic loss calculation unit is used for calculating first loss of the alternating current system when the photovoltaic power supply outputs maximum power. By real-time monitoring of output power, voltage, current and the like of the photovoltaic power supply, and combining physical characteristics of the photovoltaic module and environmental factors (such as temperature, light intensity and the like), the loss of the photovoltaic power supply to the alternating current system when outputting maximum power is accurately calculated. The loss includes energy conversion loss of the photovoltaic module, cable transmission loss, inverter conversion loss and the like. By calculating the loss, the actual available inertia support capability of the photovoltaic power supply can be more accurately evaluated, so that errors caused by excessive dependence on theoretical values are avoided.

[0059] The fan inertia calculator comprises a fan loss calculation unit; the fan loss calculation unit is used for calculating second loss of the alternating current system when the fan power supply outputs maximum power. The fan loss calculation unit has a function similar to the photovoltaic loss calculation unit, but is directed to the fan power supply. The unit calculates the loss of the fan to the alternating current system when outputting maximum power by real-time monitoring of parameters such as a rotating speed, output power and wind speed of the fan, and combining physical characteristics of the fan and a control strategy. The loss includes wind energy conversion loss, mechanical transmission loss, generator loss, cable transmission loss and the like. By accurately calculating the loss, the inertia support capability of the fan can be more accurately evaluated, and more reliable data support is provided for the inertia distribution.

[0060] The traditional unit inertia calculator includes a traditional unit loss calculation unit; the traditional unit loss calculation unit is used for calculating a third loss of the traditional unit to the AC system when the traditional unit outputs maximum power. For a traditional unit (such as a coal-fired, gas or hydroelectric generator unit), the loss calculation unit mainly focuses on mechanical loss, electrical loss, thermal loss and the like of the unit when the unit outputs maximum power. Precise calculation of these losses helps to more accurately evaluate the inertia support capability of the traditional unit, especially in the case of power grid disturbance, the traditional unit can often provide larger inertia support, and therefore, precise calculation of the loss is crucial for stable operation of the system.

[0061] The energy storage inertia calculator includes an energy storage loss calculation unit; the energy storage loss calculation unit is used for calculating a fourth loss of the energy storage power supply to the AC system when the energy storage power supply outputs maximum power. The energy storage loss calculation unit mainly targets an energy storage power supply (such as a battery energy storage system, a pumped storage power station and the like). The unit calculates the loss of the energy storage system to the AC system when the energy storage system outputs maximum power by real-time monitoring of parameters such as charging and discharging state, residual capacity, voltage, current and the like of the energy storage system, in combination with physical characteristics and control strategies of the energy storage system. These losses include battery charging and discharging loss, inverter conversion loss, transmission loss and the like. Through precise calculation of these losses, the inertia support capability of the energy storage system can be more accurately evaluated, thereby providing support for flexible dispatching and stable operation of the system.

[0062] The inertia allocator includes a sorting unit and an allocation unit; the sorting unit sorts the first loss, the second loss, the third loss and the fourth loss in ascending order; Figure 7 A sorting unit and an allocation unit of an embodiment of the utility model are shown in the schematic diagram, Figure 7 As shown in the schematic diagram, the allocation unit allocates inertia to the photovoltaic power supply, the fan power supply, the traditional unit and the energy storage power supply according to the sorting result of the sorting unit. The power supply type with smaller loss is preferentially started to output inertia, and the like is continued until the inertia demand of the AC system is met, and then all the selected inertia devices are put into operation.

[0063] Further, in the embodiment, Figure 3 A photovoltaic inertia calculator of an embodiment of the utility model is shown in the schematic diagram, Figure 3 As shown in the schematic diagram, the photovoltaic inertia calculator includes a photovoltaic direction selection unit; the photovoltaic direction selection unit determines the inertia direction of the photovoltaic power supply according to the frequency change difference of the AC system. For the photovoltaic inertia calculator, P0 is the output power of the photovoltaic power supply at this time, P vmax is the maximum power that can be output by the photovoltaic power supply, P loss is the loss of the photovoltaic power supply to the AC system when the photovoltaic power supply outputs maximum power; D f is the frequency change difference required by the AC system. The direction selection is determined according to D fThe power direction is selected according to the value of D, and the working mechanism is as follows:

[0064]

[0065] D f When D is less than 0, it indicates that the AC system is in a relatively unstable state, the output power is the maximum power that can be output by the photovoltaic power supply minus the output power of the photovoltaic power supply at this time, and the direction is negative. f When D is greater than 0, it indicates that the AC system is in a relatively stable state, the output power is the output power of the photovoltaic power supply at this time, and the direction is positive.

[0066] Figure 4 A fan inertia calculator according to an embodiment of the utility model is shown in the schematic diagram, as shown in the figure, Figure 4 The fan inertia calculator comprises a fan inertia selection unit; the fan inertia selection unit determines the inertia of the fan power supply according to the rotating speed of the fan power supply. For the fan inertia calculator, P0 is the output power of the fan power supply at this time, P wmax is the maximum power that can be output by the fan power supply, and P loss is the loss to the AC system when the fan power supply outputs the maximum power. f is the frequency change required by the AC system. w is the moment of inertia of the fan power supply itself, and n w is the rotating speed of the fan power supply. The working mechanism of the fan inertia selection unit is shown in the following formula:

[0067]

[0068] Wherein, n wmax is the maximum rotating speed allowed by the wind turbine, and n wmin is the minimum rotating speed allowed by the wind turbine. 0.9 and 1.1 are sufficient margins for the safety of equipment operation. When the rotating speed of the fan power supply is less than or equal to 0.9 times the maximum rotating speed allowed by the fan power supply or greater than or equal to 1.1 times the minimum rotating speed allowed by the fan power supply, it indicates that the fan power supply is running normally, and the moment of inertia of the fan power supply itself is selected as the output inertia; when the rotating speed of the fan power supply is greater than 0.9 times the maximum rotating speed allowed by the fan power supply or less than 1.1 times the minimum rotating speed allowed by the fan power supply, it indicates that the fan power supply is not running normally, and the output inertia is 0.

[0069] Figure 5 A traditional unit inertia calculator according to an embodiment of the utility model is shown in the schematic diagram, as shown in the figure, Figure 5 The traditional unit inertia calculator comprises a traditional unit inertia selection unit; the traditional unit inertia selection unit determines the inertia of the traditional unit according to the rotating speed of the traditional unit. For the traditional unit inertia calculator, J Tn T is the rotating speed of the conventional unit at this time. The working mechanism of the conventional unit inertia selection unit is shown in the following formula:

[0070]

[0071] n Tmax is the maximum rotating speed allowed by the conventional unit, n Tmin is the minimum rotating speed allowed by the conventional unit. 0.9 and 1.1 are sufficient margins for the safety of equipment operation. When the rotating speed of the conventional unit is less than or equal to 0.9 times the maximum rotating speed allowed by the conventional unit, or greater than or equal to 1.1 times the minimum rotating speed allowed by the conventional unit, it indicates that the conventional unit is running normally, and the rotating inertia of the conventional unit itself is selected as the output inertia; when the rotating speed of the conventional unit is greater than 0.9 times the maximum rotating speed allowed by the conventional unit or less than 1.1 times the minimum rotating speed allowed by the conventional unit, it indicates that the conventional unit is not running normally, and the output inertia is 0.

[0072] Figure 6 A schematic diagram of the energy storage inertia calculator in one embodiment of the utility model is shown, as Figure 6 shown, the energy storage inertia calculator comprises an energy storage inertia selection unit; the energy storage inertia selection unit determines the inertia of the energy storage power supply according to the residual power and the charging and discharging state of the energy storage. For the energy storage inertia calculator, P0 is the output power of the energy storage at this time, P smax is the maximum power that can be output by the energy storage, P loss is the loss of the energy storage plant to the AC system when the energy storage outputs the maximum power. D f is the frequency change required by the AC system. Table 1 shows the working mechanism of the energy storage inertia selection unit, and the working mechanism of the energy storage inertia selection unit is selected as shown in Table 1:

[0073] Table 1 Working mechanism of the energy storage inertia selection unit

[0074]

[0075] When the residual power of the energy storage power supply is less than or equal to 70%, it is in the charging state, and the output inertia is the inertia of the energy storage itself; when the residual power of the energy storage power supply is greater than 70%, it is in the discharging state, and the output inertia is 0.

[0076] The utility model obtains the inertia support capability of the photovoltaic power supply, the fan power supply, the conventional unit and the energy storage power supply through the photovoltaic inertia calculator, the fan inertia calculator, the conventional unit inertia calculator and the energy storage inertia calculator respectively; the inertia demand of the AC system is distributed through the inertia distributor, and the effective deployment of the inertia support capability of the multi-source system is realized.

[0077] It should be understood that the above detailed description of the specific embodiments of the present application is merely given for illustrative purposes and not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the appended claims of the present application are intended to cover all variations and modifications falling within the scope and boundary of the appended claims or the equivalent forms of such scope and boundary.

[0078] In the above description, the technical details such as the patterning, etching, etc. of each layer are not described in detail. However, those skilled in the art should understand that the layers, regions, etc. with the required shape can be formed by various means in the prior art. In addition, those skilled in the art can also design methods that are not exactly the same as the methods described above in order to form the same structure.

[0079] The present application has been described above with reference to the embodiments of the present application. However, these embodiments are only for illustrative purposes and not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications shall fall within the scope of the present application.

[0080] Although the embodiments of the present application have been described in detail, it should be understood that various changes, substitutions and modifications can be made to the embodiments of the present application without departing from the spirit and scope of the present application.

[0081] Obviously, the above-described embodiments are only examples for clear illustration and not a limitation on the embodiments. Based on the above description, other different forms of changes or modifications can be made by those skilled in the art. Here, it is not necessary or possible to exhaust all the embodiments. The obvious changes or modifications derived therefrom are still within the protection scope of the present application.

Claims

1. An inertia support capability allocation system for a multi-source system, characterized in that, The multi-source system comprises a photovoltaic power source, a fan power source, a traditional unit and an energy storage power source; The photovoltaic power source, the fan power source, the traditional unit and the energy storage power source are respectively connected with an alternating current system; The inertia support capability deployment system comprises a photovoltaic inertia calculator, a fan inertia calculator, a traditional unit inertia calculator, an energy storage inertia calculator and an inertia distributor; The inertia distributor is connected with the alternating current system, the photovoltaic inertia calculator, the fan inertia calculator, the traditional unit inertia calculator and the energy storage inertia calculator respectively; The photovoltaic inertia calculator is connected with the photovoltaic power source and is used for calculating the inertia support capability of the photovoltaic power source; The fan inertia calculator is connected with the fan power source and is used for calculating the inertia support capability of the fan power source; The traditional unit inertia calculator is connected with the traditional unit and is used for calculating the inertia support capability of the traditional unit; The energy storage inertia calculator is connected with the energy storage power source and is used for calculating the inertia support capability of the energy storage power source; The inertia distributor is used for distributing the inertia demand of the alternating current system according to the inertia support capability of the photovoltaic power source, the inertia support capability of the fan power source, the inertia support capability of the traditional unit and the inertia support capability of the energy storage power source.

2. The system of claim 1, wherein, The photovoltaic inertia calculator comprises a photovoltaic loss calculation unit; The photovoltaic loss calculation unit is used for calculating a first loss to the alternating current system when the photovoltaic power source outputs maximum power.

3. The system of claim 2, wherein, The fan inertia calculator comprises a fan loss calculation unit; The fan loss calculation unit is used for calculating a second loss to the alternating current system when the fan power source outputs maximum power.

4. The system of claim 3, wherein, The traditional unit inertia calculator comprises a traditional unit loss calculation unit; The traditional unit loss calculation unit is used for calculating a third loss to the alternating current system when the traditional unit outputs maximum power.

5. The system of claim 4, wherein, The energy storage inertia calculator comprises an energy storage loss calculation unit; The energy storage loss calculation unit is used for calculating a fourth loss to the alternating current system when the energy storage power source outputs maximum power.

6. The system of claim 5, wherein, The inertia distributor comprises a sorting unit and a distribution unit; The sorting unit sorts the first loss, the second loss, the third loss and the fourth loss in ascending order; The distribution unit distributes the inertia of the photovoltaic power source, the fan power source, the traditional unit and the energy storage power source according to the sorting result of the sorting unit.

7. The system of claim 1, wherein, The photovoltaic inertia calculator comprises a photovoltaic direction selection unit; The photovoltaic direction selection unit determines the inertia direction of the photovoltaic power source according to the frequency change difference of the alternating current system.

8. The system of claim 1, wherein, The fan inertia calculator comprises a fan inertia selection unit; The fan inertia selection unit determines the inertia of the fan power source according to the rotating speed of the fan power source.

9. The system of claim 1, wherein, The traditional unit inertia calculator comprises a traditional unit inertia selection unit; The traditional unit inertia selection unit determines the inertia of the traditional unit according to the rotating speed of the traditional unit.

10. The system of claim 1, wherein, The energy storage inertia calculator comprises an energy storage inertia selection unit; The energy storage inertia selection unit determines the inertia of the energy storage power source according to the remaining power and the charge and discharge state of the energy storage power source.

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