Inertia response method of wind storage coupling system, medium and system

Abstract

The invention discloses an inertia response method of a wind storage coupling system, a medium and a system, and the method comprises the steps: S1, obtaining a power grid frequency, and obtaining a power grid frequency change rate according to the power grid frequency; s2, comparing the power grid frequency change rate with a corresponding preset threshold value; when the power grid frequency change rate exceeds a preset threshold value, calculating power required by inertia response; s3, according to the real-time state of the energy storage system, dynamically distributing power required by inertia response to a fan end and an energy storage end for power response; and S4, after the inertia response exits, inputting the energy storage system to realize smooth transition of the active power of the outlet to the state before the inertia response. According to the invention, rapid and accurate response of inertia is realized, fluctuation of the power grid frequency is stabilized, and safety and stability of the power grid frequency are ensured. According to the invention, rapid and accurate response of inertia can be realized, fluctuation of the power grid frequency is stabilized, and safety and stability of the power grid frequency are ensured.

Description

Technical Field

[0001] The present invention mainly relates to the field of wind power technology, and in particular to an inertia response method, a medium and a system of a wind-storage coupling system. Background Art

[0002] Energy is the cornerstone of human survival and social development. With the development of social economy and the advancement of science and technology, the relationship between energy supply and demand has become increasingly tense, and the energy system dominated by non-renewable energy has gradually revealed its drawbacks. Wind power generation has emerged as a new force in the field of renewable energy with its mature technology and huge potential.

[0003] However, with the increasing penetration of wind power into the power grid, this has brought considerable challenges to the safe and stable operation of the power system. After wind power is connected to the grid, the inertial response time constant of the power system decreases, and the inertia of the entire power system is further reduced. At this time, the maximum frequency deviation may exceed the normal range, which will have a huge impact on the safety and stability of the entire power system.

[0004] In recent years, it has been proposed to use the kinetic energy released by the wind turbine rotor to respond to inertia in order to maintain the stability of the power system frequency. However, when the inertia demand is large, the impact on the load of the wind turbine generator set will be great. Moreover, the solution using rotor kinetic energy will cause secondary power fluctuations after the inertia is withdrawn, which will aggravate the fluctuation of the power grid frequency. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention provides an inertia response method, medium and system for a wind-storage coupling system that can achieve fast and accurate response of inertia, stabilize the fluctuation of grid frequency, and ensure the safety and stability of grid frequency.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] An inertia response method for a wind-storage coupling system comprises the following steps:

[0008] S1, obtaining the grid frequency, and changing the grid frequency according to the grid frequency;

[0009] S2. Compare the grid frequency change rate with the corresponding preset threshold; when the grid frequency change rate exceeds the preset threshold, calculate the power required for inertia response;

[0010] S3. According to the real-time status of the energy storage system, the power required for inertia response is dynamically allocated to the wind turbine end and the energy storage end for power response;

[0011] S4. After the inertia response exits, the energy storage system is put into use to achieve a smooth transition of the export active power to the state before the inertia response.

[0012] Preferably, the specific process in step S3 is:

[0013] Determine whether the power ΔP required for inertia response is greater than 0; if it is less than 0, it means that there is frequency disturbance, and all ΔP is allocated to the fan for response;

[0014] If the power required for inertia response is greater than 0, all ΔP is allocated to the energy storage system for response; during the response of the energy storage system, the energy storage system SCO is detected; when the SOC is lower than the warning threshold Lev1, ΔP is gradually transferred to the wind turbine end for response.

[0015] Preferably, during the process of gradually transitioning ΔP to the wind turbine end for response, the outlet active power is kept unchanged.

[0016] Preferably, after ΔP is gradually transferred to the wind turbine end for response, when the inertia is withdrawn, the energy storage system is put into use to stabilize the export active power at the state before the inertia response.

[0017] Preferably, after all ΔP is allocated to the wind turbine for response, when the inertia is withdrawn, the energy storage system is put into use to stabilize the export active power at the state before the inertia response.

[0018] Preferably, in step S2, the calculation formula of the inertia response required power ΔP is:

[0019]

[0020] Among them, T j is the inertia time constant, in seconds; f N is the rated frequency of the power grid, in Hz; is the frequency change rate of the grid connection point, in Hz / s; P n is the rated power of the fan.

[0021] Preferably, in step S1, the grid frequency is acquired and filtered to remove abnormal values.

[0022] The present invention also discloses a computer program product, comprising a computer program, wherein the computer program executes the steps of the method described above when executed by a processor.

[0023] The present invention further discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described above are executed.

[0024] The present invention also discloses an inertia response system of a wind-storage coupling system, comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, and when the computer program is run by the processor, the steps of the method described above are executed.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The present invention adds an energy storage system to the wind turbine generator set, determines the power required for the inertia response of the wind-storage coupling system when it is judged that the rate of change of the grid frequency exceeds the dead zone, and dynamically distributes the power required for the inertia response to the wind turbine and the energy storage system, so as to achieve a fast and accurate response of the inertia, stabilize the fluctuation of the grid frequency, and ensure the safety and stability of the grid frequency; and after the inertia is withdrawn, the energy storage system is put into use to achieve a smooth transition of the export active power to the state before the inertia response, effectively avoiding the secondary fluctuation of the grid caused by the withdrawal of the inertia response, thereby ensuring the safety and stability of the grid frequency.

[0027] The present invention dynamically switches commands during the inertia response period, does not require full-process energy storage response inertia, and requires a lower energy storage SOC, which can effectively reduce costs while meeting performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a topological diagram of the wind-storage coupling system in an embodiment of the present invention.

[0029] Figure 2 It is a flow chart of an inertia response method in an embodiment of the present invention.

[0030] Figure 3 It is a flow chart of the inertia response and exit process in the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] like Figure 1-Figure 2 As shown, the inertia response method of the wind-storage coupling system provided by the embodiment of the present invention includes the following steps:

[0033] S1. Detect the grid frequency through the converter, perform sliding window filtering on the grid frequency, filter out abnormal values, and calculate the grid frequency change rate within a period of time;

[0034] S2. Compare the grid frequency change rate with a preset threshold value (such as ±0.3 Hz / s); when the grid frequency change rate exceeds the preset threshold value, calculate the power required for inertia response;

[0035] S3. According to the real-time status of the energy storage system, the power required for inertia response is dynamically allocated to the wind turbine end and the energy storage end for power response;

[0036] S4: After the inertia exits, the energy storage system is put into use to achieve a smooth transition of the export active power to the initial state before the inertia response.

[0037] In step S2, the power ΔP required for inertia response is calculated:

[0038]

[0039] Among them, T j is the inertia time constant, in seconds; f N is the rated frequency of the power grid, in Hz; is the frequency change rate of the grid connection point, in Hz / s; P n is the rated power of the fan.

[0040] like Figure 3 As shown, the specific process of steps S3-S4 is:

[0041] Determine whether the power required for inertia response is greater than 0; if less than 0, it indicates frequency disturbance, and all ΔP is allocated to the wind turbine for response; when the inertia is removed, the energy storage system is put into operation to stabilize the export active power to the state before the inertia response;

[0042] If the power required for inertia response is greater than 0, check whether the SOC of the energy storage system is within the normal range; if the SOC of the energy storage system is within the normal range, allocate all ΔP to the energy storage system response; as the SCO of the energy storage system gradually decreases, when the SOC is lower than the warning threshold Lev1, gradually transfer ΔP to the wind turbine end for response. This process keeps the export active power unchanged, and only completes the switching of the internal instructions of the wind turbine and the energy storage system; the SOC warning threshold Lev1 is obtained after comprehensive evaluation of the wind turbine power level and the battery capacity of the energy storage system (for example, the rated power of the wind turbine is 5MW, the battery capacity of the energy storage system is 500kwh, and the SOC warning threshold Lev1 is set to 10%); when the inertia is exited, there will be a secondary fluctuation of power at the wind turbine end. At this time, the energy storage system is immediately put into use to stabilize the export active power at the state before the inertia response. The above scheme can ensure the stability of the export active power of the wind-storage coupling system during the entire inertia response process, and will not cause secondary fluctuations in the power grid.

[0043] The present invention adds an energy storage system to the wind turbine generator set, determines the power required for the inertia response of the wind-storage coupling system when it is judged that the rate of change of the grid frequency exceeds the dead zone, and dynamically distributes the power required for the inertia response to the wind turbine and the energy storage system, so as to achieve a fast and accurate response of the inertia, stabilize the fluctuation of the grid frequency, and ensure the safety and stability of the grid frequency; and after the inertia is withdrawn, the energy storage system is put into use to achieve a smooth transition of the export active power to the state before the inertia response, effectively avoiding the secondary fluctuation of the grid caused by the withdrawal of the inertia response, thereby ensuring the safety and stability of the grid frequency.

[0044] The present invention dynamically switches commands during the inertia response period, does not require full-process energy storage response inertia, and requires a lower energy storage SOC, which can effectively reduce costs while meeting performance requirements.

[0045] The present invention also discloses a computer program product, including a computer program, which executes the steps of the above method when executed by a processor. The present invention further discloses a computer-readable storage medium, which stores a computer program, which executes the steps of the above method when executed by a processor. The present invention also discloses an inertia response system of a wind-storage coupling system, including a memory and a processor connected to each other, the memory stores a computer program, and the computer program executes the steps of the above method when executed by the processor.

[0046] The product, medium and system of the present invention correspond to the above method and also have the advantages described in the above method.

[0047] The present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiment when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media include: any entity or device that can carry computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. The memory is used to store computer programs and / or modules, and the processor implements various functions by running or executing computer programs and / or modules stored in the memory, and calling data stored in the memory. The memory may include high-speed random access memory and may also include non-volatile memory, such as a hard disk, an internal memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0048] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. An inertia response method for a wind-storage coupling system, characterized in that: Includes steps: S1, obtaining the grid frequency, and changing the grid frequency according to the grid frequency; S2. Compare the grid frequency change rate with the corresponding preset threshold; when the grid frequency change rate exceeds the preset threshold, calculate the power required for inertia response; S3. According to the real-time status of the energy storage system, the power required for inertia response is dynamically allocated to the wind turbine end and the energy storage end for power response; S4. After the inertia response exits, the energy storage system is put into operation to realize a smooth transition of the export active power to the state before the inertia response.

2. The inertia response method of the wind-storage coupling system according to claim 1 is characterized in that: The specific process in step S3 is: Determine whether the power ΔP required for inertia response is greater than 0; if it is less than 0, it means that there is frequency disturbance, and all ΔP is allocated to the fan for response; If the power required for inertia response is greater than 0, all ΔP is allocated to the energy storage system for response; during the response of the energy storage system, the energy storage system SCO is detected; when the SOC is lower than the warning threshold Lev1, ΔP is gradually transferred to the wind turbine end for response.

3. The inertia response method of the wind-storage coupling system according to claim 2 is characterized in that: In the process of gradually transferring ΔP to the wind turbine end for response, the export active power remains unchanged.

4. The inertia response method of the wind-storage coupling system according to claim 3 is characterized in that: After gradually transferring ΔP to the wind turbine end for response, when the inertia exits, the energy storage system is put into use to stabilize the export active power at the state before the inertia response.

5. The inertia response method of the wind-storage coupling system according to claim 2 is characterized in that: After all ΔP is allocated to the wind turbine for response, when the inertia exits, the energy storage system is put into use to stabilize the export active power at the state before the inertia response.

6. The inertia response method of the wind-storage coupling system according to any one of claims 1 to 5, characterized in that: In step S2, the calculation formula of the inertia response required power ΔP is: Among them, T j is the inertia time constant, in seconds; f N is the rated frequency of the power grid, in Hz; It is the frequency change rate of the grid connection point, in Hz / s.

7. The inertia response method of the wind-storage coupling system according to any one of claims 1 to 5, characterized in that: In step S1, the grid frequency is acquired and filtered to remove abnormal values.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are performed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

10. An inertial response system of a wind-storage coupling system, comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

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