Inertia support-based power control method and device for new energy plant station

Abstract

Embodiments of the present application relate to a kind of new energy plant station power control method and device based on inertia support, the method comprises: the current operating frequency and current power of alternating current system are detected;Based on the current operating frequency and current power, the total power P of new energy plant station for inertia support is calculated;The power parameter of each device of new energy plant station is acquired;Based on the total power P of new energy plant station and the power parameter of each device of new energy plant station, power direction discrimination is carried out;Based on the result of power direction discrimination, power distribution is carried out.The technical scheme provided by the embodiments of the present application determines the inertia output of each device under different inertia support conditions according to the capacity requirement of each device in new energy plant station and network topology, so as to ensure the accurate processing of each device and improve the inertia capacity of new energy plant station.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power system power control technology, and in particular to a power control method and device for new energy power plants based on inertia support. Background Technology

[0002] Currently, in the field of secondary frequency regulation engineering, the output power of each unit is often allocated proportionally based on the adjustable capacity. This method is called proportional allocation, but this strategy cannot meet the optimal control requirements of the system. In addition, most current research on wind and solar renewable energy participating in frequency regulation focuses on controller design and the control strategies of wind farms and photovoltaic power plants themselves, with less research on the coordinated control between wind and solar renewable energy and other frequency regulation resources.

[0003] In recent years, to enable new energy systems to possess the characteristics of inertia and damping, scholars have discovered that virtual synchronous machine (VSG) control can simulate the advantages of inertia and damping in traditional power systems. It can also achieve multiple functions such as frequency and voltage regulation and power distribution, greatly improving system stability. Currently, microgrid systems generally use multiple units connected in parallel. However, if the connection impedance and equivalent output impedance values ​​between each VSG are different, reactive power will circulate, and it will be difficult to distribute reactive power evenly, leading to reduced system stability and damage to power electronic devices. Summary of the Invention

[0004] Based on the above-mentioned situation of the prior art, the purpose of this invention is to provide a power control method and device for new energy power plants based on inertia support. According to the capacity requirements of each device in the new energy power plant and the network topology, the inertia output of each device under different inertia support conditions is determined, thereby ensuring the accurate output of each device and improving the inertia capability of the new energy power plant.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a power control method for new energy power plants based on inertia support is provided, wherein the new energy power plant is connected to an AC system, and the method includes the following steps:

[0006] Detect the current operating frequency and current power of the AC system;

[0007] Calculate the total power P of the new energy power plant used for inertia support based on the current operating frequency and current power.

[0008] Obtain the power parameters of each piece of equipment in the new energy power plant;

[0009] Power direction is determined based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant.

[0010] Power allocation is performed based on the results of power direction discrimination.

[0011] Furthermore, based on the current operating frequency and current power, the total power of the new energy power plant used for inertia support is calculated, including calculating the total power P of the new energy power plant used for inertia support according to the following formula:

[0012]

[0013] Where f0 represents the current operating frequency of the AC system, f ref This represents the preset frequency reference value, G. s P0 represents the inertia control transfer function, and P0 represents the current power of the AC system.

[0014] Furthermore, the new energy power plant includes new energy power generation equipment, energy storage equipment, and static var generator (SVG). The new energy power generation equipment includes at least one new energy inverter, and the energy storage equipment includes at least one energy storage inverter.

[0015] The power parameters of each piece of equipment in the new energy power plant include the maximum active power P output by the new energy inverter. nmax The maximum active power P of the energy storage inverter smax At times when inertia support is required, the active power P output by the operating new energy inverter... n0 The active power output capacity P of the energy storage system s0 The minimum operating active power P of the new energy inverter nmin The minimum active power P of the energy storage inverter smin .

[0016] Furthermore, power direction determination is performed based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant, including:

[0017] Based on the relationship between the total power P of the new energy power plant and the current power P0 of the AC system, and the relationship between the difference ΔP and the power parameters of each device in the new energy power plant, the power of the new energy power generation equipment and the energy storage equipment is allocated; wherein, the difference ΔP represents the difference between the total power P of the new energy power plant and the current power P0 of the AC system.

[0018] Furthermore, based on the relationship between the total power P of the new energy power plant and the current power P0 of the AC system, and the relationship between the difference ΔP and the power parameters of each device in the new energy power plant, the power of the new energy power generation equipment and the energy storage equipment is allocated, including determining the power of the new energy power generation equipment according to the following formula:

[0019] When P > P0

[0020]

[0021] When P≤P0

[0022]

[0023] Among them, P n This indicates the active power command value of the new energy inverter.

[0024] Furthermore, based on the relationship between the total power P of the new energy power plant and the current power P0 of the AC system, and the relationship between the difference ΔP and the power parameters of each device in the new energy power plant, the power of the new energy power generation equipment and the energy storage equipment is allocated, including determining the power of the energy storage equipment according to the following formula:

[0025] When P > P0

[0026]

[0027] When P≤P0

[0028]

[0029] Among them, P s This indicates the active power command value of the energy storage inverter.

[0030] Furthermore, power allocation is performed based on the power direction determination results, including:

[0031] Based on the determined power of the new energy power generation equipment, the active power command value of each new energy inverter is set according to the following formula:

[0032]

[0033] Among them, P nref Z represents the active power command value of a single renewable energy inverter. i The impedance of the new energy inverter to the PCC common connection point is represented by x, and x represents the number of new energy inverters in the plant.

[0034] Furthermore, power allocation is performed based on the power direction determination results, including:

[0035] Based on the determined power of the new energy power generation equipment, the active power command value of each energy storage inverter is set according to the following formula:

[0036]

[0037] Among them, P sref This represents the active power command value of a single energy storage inverter, and n represents the number of energy storage inverters in the plant.

[0038] Furthermore, power allocation based on the power direction determination results also includes controlling the reactive power output of the static var generator (SVG):

[0039] If Q0 max ,but

[0040] If Q0≥Q max Then Q ref =Q max ;

[0041] Among them, Q ref This represents the reactive power command value output by the Static Var Generator (SVG), where Q0 represents the current reactive power of the SVG. max U represents the maximum output reactive power of the static var generator (SVG). ref G represents the AC voltage reference value for the AC system. g This represents the voltage regulation coefficient.

[0042] According to another aspect of the present invention, a power control device for a new energy power plant based on inertia support is provided, wherein the new energy power plant is connected to an AC system, and the device comprises:

[0043] The operation detection module is used to detect the current operating frequency and current power of the AC system;

[0044] The total power acquisition module is used to calculate the total power P of the new energy power plant for inertia support based on the current operating frequency and the current power.

[0045] The equipment parameter acquisition module is used to acquire the power parameters of various equipment in new energy power plants;

[0046] The power direction determination module is used to determine the power direction based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant.

[0047] The power allocation module is used to allocate power based on the result of power direction determination.

[0048] ​In summary, this invention provides a power control method and apparatus for new energy power plants based on inertia support. The method includes the following steps: detecting the current operating frequency and current power of the AC system; calculating the total power P of the new energy power plant for inertia support based on the current operating frequency and current power; obtaining the power parameters of each device in the new energy power plant; determining the power direction based on the total power P and the power parameters of each device; and allocating power based on the result of the power direction determination. The technical solution provided by this invention, on the one hand, determines the output priority and capacity requirements of each device for inertia support by determining the reserve capacity of each device in the new energy power plant, comprehensively considering various factors, and determining the inertia output of each device under different inertia support conditions, thus fully utilizing the inertia capability of the new energy power plant; on the other hand, by determining the inertia capacity of each device in the new energy power plant, and based on the network topology of the new energy power plant, the output of each unit for inertia support is determined, thereby achieving accurate output of each unit module in each device. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the overall configuration of new energy power plants;

[0050] Figure 2 This is a flowchart of the power control method for new energy power plants based on inertia support provided in an embodiment of the present invention;

[0051] Figure 3 This is a control block diagram of the power control method for new energy power plants based on inertia support provided in an embodiment of the present invention;

[0052] Figure 4 This is a control block diagram for active power control in existing technology;

[0053] Figure 5 This is a control block diagram for reactive power control in existing technologies. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0055] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in one or more embodiments of the present invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0056] Currently, the inertia support capability of new energy power plants in the engineering field mainly considers the energy storage equipment configured within the power plants, but this cannot fully utilize the overall inertia support function of the new energy system, including the inertia regulation capability of new energy inverters and SVG inverters. Typically, inertial and damping elements are set up for active power, while a droop coefficient is considered for reactive power. By detecting changes in active and reactive power, the AC frequency and AC voltage are adjusted, and a certain inertial time constant is provided during the adjustment process to simulate the changing characteristics of a traditional generator. Figure 4 The diagram shows a control block diagram for active power control. Figure 5 The diagram shows a control block diagram for reactive power control.

[0057] The aforementioned virtual inertia control method can ensure the stable output of virtual inertia for a single new energy equipment system. However, in multi-parallel systems, it cannot accurately guarantee the virtual inertia output of each unit, and may even lead to oscillations and circulating currents between devices. Furthermore, current systems only consider the inertia support capability of energy storage devices, without comprehensively considering the overall effect of the inertia support capability of new energy power generation equipment and static var generators (SVG), thus failing to fully utilize the inertia support capability of new energy power plants. To address these technical problems, this invention provides a power control method and device for new energy power plants based on inertia support.

[0058] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings. An embodiment of the present invention provides a power control method for new energy power plants based on inertia support. Figure 1 The diagram shows the overall configuration of the new energy power plant. For example... Figure 1As shown, a renewable energy power plant includes renewable energy generation equipment, energy storage equipment, and a static var generator (SVG). The renewable energy generation equipment includes, for example, wind power generation equipment and photovoltaic power generation equipment, and each renewable energy generation device includes at least one renewable energy inverter. The energy storage equipment includes at least one energy storage inverter, used to smooth the voltage output from the renewable energy generation equipment to the AC system. The renewable energy power plant is interconnected with the AC system via busbars. The PCC point of the renewable energy power plant is the Point of Common Coupling, which typically refers to the load connection point of more than one user in the power system.

[0059] Figure 2 The flowchart of the power control method for new energy power plants based on inertia support according to an embodiment of the present invention is shown. Figure 3 The diagram shows a control block diagram of the power control method for new energy power plants based on inertia support according to an embodiment of the present invention. Figure 2 and Figure 3 As shown, the method includes the following steps:

[0060] S202. Detect the current operating frequency and power of the AC system. The current operating frequency and power of the AC system can be obtained by detecting parameters such as the operating voltage and operating current of the AC system.

[0061] S204. Calculate the total power P of the new energy power plant used for inertia support based on the current operating frequency and current power. According to the obtained current operating frequency and current power of the AC system,

[0062] f ref =f0-G s (P-P0)

[0063] Where f0 represents the current operating frequency of the AC system, f ref This represents the preset frequency reference value, G. s P0 represents the inertia control transfer function, and P0 represents the current power of the AC system.

[0064] From the above formula, the total power P of the new energy power plant used for inertia support can be obtained:

[0065]

[0066] S206. Obtain the power parameters of each device in the new energy power plant. The power parameters of each device in the new energy power plant include the maximum active power P output by the new energy inverter. nmax The maximum active power P of the energy storage inverter smax At times when inertia support is required, the active power P output by the operating new energy inverter... n0 The active power output capacity P of the energy storage system s0The minimum operating active power P of the new energy inverter nmin The minimum active power P of the energy storage inverter smin .

[0067] S208. Power direction determination is performed based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant. In this embodiment of the invention, the power of the new energy power generation equipment and the energy storage equipment is allocated based on the relationship between the total power P of the new energy power plant and the current power P0 of the AC system, and the relationship between the difference ΔP and the power parameters of each device in the new energy power plant; wherein, the difference ΔP represents the difference between the total power P of the new energy power plant and the current power P0 of the AC system. Specifically, the allocation can be performed according to the following formula:

[0068] When P > P0

[0069]

[0070] When P≤P0

[0071]

[0072]

[0073] Among them, P n P represents the active power command value of the new energy inverter. s This indicates the active power command value of the energy storage inverter.

[0074] In this embodiment of the invention, by determining the output priority and capacity requirements of inertia support for new energy equipment, energy storage equipment and SVG, and by comprehensively considering various factors, the inertia output of each device is determined under different inertia support conditions, so as to give full play to the inertia capacity of new energy power plants.

[0075] S210. Power allocation is performed based on the power direction determination results. Through the above calculations, the power ratio allocation between energy storage devices and new energy devices can be determined. Based on the ratio allocation results, the active power of each new energy inverter and energy storage inverter in the energy storage devices and new energy devices can be set.

[0076] The active power of the new energy inverter is set based on the determined power of the new energy equipment. Considering the distributed characteristics of the new energy equipment, the impact of the wiring impedance of the distributed new energy equipment on power distribution needs to be taken into account. The active power command value of each new energy inverter is set according to the following formula:

[0077]

[0078] Among them, P nrefZ represents the active power command value of a single renewable energy inverter. i The impedance of the new energy inverter to the PCC common connection point is represented by x, and x represents the number of new energy inverters in the plant.

[0079] The active power of the energy storage inverter is set based on the determined power of the energy storage device. Since energy storage devices are usually centrally configured, the power of each energy storage inverter can be allocated in a power-sharing manner. The active power command value of each energy storage inverter is set according to the following formula:

[0080]

[0081] Among them, P sref This represents the active power command value of a single energy storage inverter, and n represents the number of energy storage inverters in the plant.

[0082] By using the above-described allocation method provided in this embodiment of the invention to allocate power to each inverter of new energy equipment and energy storage equipment, the output supported by the inertia of each unit can be determined, thereby ensuring the accurate output of each inverter unit.

[0083] According to certain optional embodiments, power allocation based on the result of power direction determination also includes controlling the reactive power output of the static var generator (SVG):

[0084] If Q0 max ,but

[0085] If Q0≥Q max Then Q ref =Q max ;

[0086] Among them, Q ref This represents the reactive power command value output by the Static Var Generator (SVG), where Q0 represents the current reactive power of the SVG. max U represents the maximum output reactive power of the static var generator (SVG). ref G represents the AC voltage reference value for the AC system. g This represents the voltage regulation coefficient.

[0087] An embodiment of the present invention also provides a power control device for a new energy power plant based on inertia support, wherein the new energy power plant is connected to an AC system, and the device includes:

[0088] The operation detection module is used to detect the current operating frequency and current power of the AC system;

[0089] ​The total power acquisition module is used to calculate the total power P of the new energy power plant for inertia support based on the current operating frequency and the current power.

[0090] The equipment parameter acquisition module is used to acquire the power parameters of various equipment in new energy power plants;

[0091] The power direction determination module is used to determine the power direction based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant.

[0092] The power allocation module is used to allocate power based on the result of power direction determination.

[0093] The specific process by which each module in the power control device for new energy power plants based on inertia support realizes its function is the same as the steps of the power control method for new energy power plants based on inertia support involved in the above embodiments of the present invention, and its repeated description will be omitted here.

[0094] In summary, the embodiments of the present invention relate to a power control method and apparatus for new energy power plants based on inertia support. The method includes the following steps: detecting the current operating frequency and current power of the AC system; calculating the total power P of the new energy power plant for inertia support based on the current operating frequency and current power; obtaining the power parameters of each device in the new energy power plant; determining the power direction based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant; and allocating power based on the result of the power direction determination. The technical solution provided by the embodiments of the present invention, on the one hand, determines the output priority and capacity requirements of each device for inertia support by determining the reserve capacity of each device in the new energy power plant, comprehensively considering various factors, and determining the inertia output of each device under different inertia support conditions, thereby fully utilizing the inertia capability of the new energy power plant; on the other hand, by determining the inertia capacity of each device in the new energy power plant, and based on the network topology of the new energy power plant, determining the output of each unit for inertia support, thereby realizing the accurate output of each unit module in each device.

[0095] It should be understood that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of this invention, technical features of the above embodiments or different embodiments can also be combined, steps can be implemented in any order, and many other variations exist regarding different aspects of one or more embodiments of the invention as described above, which are not provided in the details for the sake of brevity. The specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A power control method for new energy power plants based on inertia support, characterized in that, The method for connecting the new energy power plant to the AC system includes the following steps: Detect the current operating frequency and current power of the AC system; Calculate the total power P of the new energy power plant used for inertia support based on the current operating frequency and current power. Obtain the power parameters of each device in the new energy power plant; the power parameters of each device in the new energy power plant include the maximum active power P output by the new energy inverter. nmax The maximum active power P of the energy storage inverter smax At times when inertia support is required, the active power P output by the operating new energy inverter... n0 The active power P of the energy storage system s0 The minimum operating active power P of the new energy inverter nmin The minimum active power P of the energy storage inverter smin ; Power direction determination is performed based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant, including: allocating power between the new energy power generation equipment and the energy storage equipment based on the relationship between the total power P of the new energy power plant and the current power P0 of the AC system, and the relationship between the difference ΔP and the power parameters of each device in the new energy power plant; including determining the power of the new energy power generation equipment according to the following formula: When P > P0 When P≤P0 Wherein, the difference ΔP represents the difference between the total power P of the new energy power plant and the current power P0 of the AC system, P n P represents the active power command value of the new energy inverter. s This indicates the active power command value of the energy storage inverter; it also includes determining the power of the energy storage device according to the following formula: When P > P0 When P≤P0 Among them, P s This indicates the active power command value of the energy storage inverter; Power allocation is performed based on the results of power direction discrimination.

2. The method according to claim 1, characterized in that, The total power of new energy power plants used for inertia support is calculated based on the current operating frequency and current power, including calculating the total power P of new energy power plants used for inertia support according to the following formula: Where f0 represents the current operating frequency of the AC system, f ref This represents the preset frequency reference value, G. s P0 represents the inertia control transfer function, and P0 represents the current power of the AC system.

3. The method according to claim 1, characterized in that, The new energy power plant includes new energy power generation equipment, energy storage equipment and static var generator (SVG). The new energy power generation equipment includes at least one new energy inverter, and the energy storage equipment includes at least one energy storage inverter.

4. The method according to claim 3, characterized in that, Power allocation is performed based on the results of power direction determination, including: Based on the determined power of the new energy power generation equipment, the active power command value of each new energy inverter is set according to the following formula: Among them, P nref Z represents the active power command value of a single renewable energy inverter. i This represents the impedance from the new energy inverter to the point of common coupling (PCC), and x represents the number of new energy inverters in the plant.

5. The method according to claim 4, characterized in that, Power allocation is performed based on the results of power direction determination, including: Based on the determined power of the new energy power generation equipment, the active power command value of each energy storage inverter is set according to the following formula: Among them, P sref This represents the active power command value of a single energy storage inverter, and n represents the number of energy storage inverters in the plant.

6. The method according to claim 4 or 5, characterized in that, Power allocation based on power direction determination results also includes controlling the reactive power output of the static var generator (SVG): If Q0 max ,but ​ If Q0≥Q max Then Q ref =Q max ; Among them, Q ref This represents the reactive power command value output by the Static Var Generator (SVG), where Q0 represents the current reactive power of the SVG. max U represents the maximum output reactive power of the static var generator (SVG). ref G represents the AC voltage reference value for the AC system. g This represents the voltage regulation coefficient.

7. A power control device for new energy power plants based on inertia support, characterized in that, The control device is controlled by the method described in any one of claims 1-6, the new energy power plant is connected to an AC system, and the device includes: The operation detection module is used to detect the current operating frequency and current power of the AC system; The total power acquisition module is used to calculate the total power P of the new energy power plant for inertia support based on the current operating frequency and the current power. The equipment parameter acquisition module is used to acquire the power parameters of various equipment in new energy power plants; The power direction determination module is used to determine the power direction based on the total power P of the new energy power plant and the power parameters of each device in the new energy power plant. The power allocation module is used to allocate power based on the result of power direction determination.

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