A reactive power coordinated control method and device for a wind-solar-storage combined power station

Abstract

The application discloses a kind of reactive power coordinated control method and device of wind and light storage combined power station, and the method comprises: obtaining reactive power regulation total instruction and the first reactive power adjustable margin of SVG;According to regulation total instruction and the first reactive power adjustable margin, when regulation total amount is less than or equal to the first reactive power adjustable margin, regulation total amount is all distributed to SVG;Otherwise, regulation total amount is preferentially distributed to SVG so that the first reactive power adjustable margin is zero, execute next step;According to the reactive power adjustable margin of energy storage, wind and light, the distribution priority between wind and light and energy storage, the first reactive power remaining regulation amount is distributed, and the reactive power regulation amount of wind and light, energy storage is obtained respectively, if wind and light reactive power regulation amount is greater than zero, execute next step;According to the distribution strategy between wind power and photovoltaic, the reactive power adjustable margin of wind power and photovoltaic, wind and light reactive power regulation amount is distributed, and the reactive power regulation amount of wind power and photovoltaic is obtained respectively.The application flexibly coordinates and controls reactive power according to actual operation.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a reactive power coordination control method and device for a wind-solar-storage combined power station. Background Technology

[0002] In recent years, new energy power generation such as wind and solar power has been developed vigorously. However, wind and solar power generation are characterized by randomness, intermittency and volatility. Coupled with technical bottlenecks in forecasting, scheduling and control, the independent power generation characteristics and source-grid coordination characteristics of these two new energy sources are still quite different from those of conventional power sources. The large-scale integration of new energy power plants has had a great impact on the safe and stable operation of the power system. Among them, reactive power coordination control is one of the more common problems in actual operation.

[0003] With the development of large-scale renewable energy power plants, combined wind-solar-storage power stations are a future hot trend. Furthermore, these combined wind-solar-storage power stations are typically equipped with dynamic var compensators (SVG). For combined wind-solar-storage power stations, due to the presence of multiple reactive power control devices, coordinated reactive power control of various power generation equipment is crucial.

[0004] When performing reactive power coordination control, existing technologies typically assume that wind power, photovoltaic power, and energy storage have equal priority. This approach fails to flexibly coordinate reactive power control based on the actual operating conditions of the power system, which negatively impacts the stability, reliability, and economy of the power system's grid-connected operation. Summary of the Invention

[0005] The purpose of this invention is to provide a reactive power coordination control method and device for a wind-solar-storage combined power station, so as to solve the technical problem that the existing technology cannot flexibly carry out reactive power coordination control according to the actual operation of the power system.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A reactive power coordination control method for a wind-solar-storage combined power station includes:

[0008] S1: Obtain the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total reactive power adjustment amount and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction.

[0009] S2: Perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, allocate the entire total reactive power adjustment to the dynamic reactive power compensation device according to the adjustment direction; otherwise, allocate the total reactive power adjustment to the dynamic reactive power compensation device first to make the first reactive power adjustable margin zero, and then execute S3.

[0010] S3: Based on the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system, and the adjustment direction, the first reactive power surplus adjustment amount is allocated between the wind and solar system and energy storage in a second reactive power distribution, respectively obtaining the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage. If the first reactive power adjustment amount is greater than zero, proceed to S4; the first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin.

[0011] S4: Based on the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power, and the adjustment direction, the first reactive power adjustment amount is allocated between wind power and photovoltaic power in a third reactive power distribution, thereby obtaining the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power.

[0012] Optionally, the allocation strategy between wind power and photovoltaic power in the wind-solar system is as follows:

[0013] Allocation strategy based on proportion or allocation strategy based on priority.

[0014] Optionally, the proportional allocation strategy includes:

[0015] When the adjustment direction is upward, the reactive power between wind power and photovoltaic power is allocated according to the ratio of the maximum reactive power between wind power and photovoltaic power.

[0016] Optionally, the proportional allocation strategy includes:

[0017] When the adjustment direction is downward, the reactive power between wind power and photovoltaic power is allocated according to the minimum reactive power ratio between wind power and photovoltaic power.

[0018] Optionally, when the reactive power adjustment direction is upward, the reactive power adjustment margin of the dynamic reactive power compensation device is the first reactive power upward adjustment margin; otherwise, the reactive power adjustment margin of the dynamic reactive power compensation device is the first reactive power downward adjustment margin.

[0019] Optionally, when the reactive power adjustment direction is upward, the second reactive power adjustable margin of the energy storage is the second reactive power upward adjustment margin; otherwise, the second reactive power adjustable margin of the energy storage is the second reactive power downward adjustment margin.

[0020] Optionally, the method further includes the following steps before step S2:

[0021] When the adjustment direction is upward, the current reactive power output and maximum reactive power of energy storage, wind power, and photovoltaic power are obtained respectively.

[0022] When the adjustment direction is downward, the current reactive power output and minimum reactive power of energy storage, wind power, and photovoltaic power are obtained respectively.

[0023] Optionally, when the reactive power adjustment direction is upward, the fourth reactive power adjustable margin of the wind power is the difference between the maximum reactive power of the wind power and the current reactive power output.

[0024] Otherwise, the fourth reactive power adjustable margin of the wind power is the difference between the current reactive power output of the wind power and the minimum reactive power.

[0025] Optionally, when the reactive power adjustment direction is upward, the fifth reactive power adjustable margin of the photovoltaic is the difference between the maximum reactive power of the photovoltaic and the current reactive power output.

[0026] Otherwise, the fifth reactive power adjustable margin of the photovoltaic system is the difference between the current reactive power output of the photovoltaic system and the minimum reactive power.

[0027] The present invention also provides a reactive power coordination control device for a wind-solar-storage combined power station, comprising:

[0028] The initial data acquisition module is used to acquire the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total reactive power adjustment amount and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction.

[0029] The first reactive power allocation module is used to perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, the total reactive power adjustment is allocated to the dynamic reactive power compensation device according to the adjustment direction; otherwise, the total reactive power adjustment is preferentially allocated to the dynamic reactive power compensation device to make the first reactive power adjustable margin zero, and then the second reactive power allocation module is executed.

[0030] The second reactive power allocation module is used to perform a second reactive power allocation between the wind and solar system and energy storage based on the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system, and the adjustment direction. This results in the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage. If the first reactive power adjustment amount is greater than zero, the third reactive power allocation module is executed. The first reactive power remaining adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin.

[0031] The third reactive power allocation module is used to perform a third reactive power allocation between wind power and photovoltaic power according to the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power and the adjustment direction, so as to obtain the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power respectively.

[0032] This invention provides a reactive power coordination control method and apparatus for a wind-solar-storage combined power station, wherein the method includes: S1: obtaining a total reactive power regulation command and a first reactive power adjustable margin of a dynamic reactive power compensation device, wherein the total reactive power regulation command includes the total amount of reactive power to be regulated and the reactive power regulation direction, wherein the reactive power regulation direction includes an upward adjustment direction and a downward adjustment direction; S2: performing a first reactive power allocation according to the total reactive power regulation command and the first reactive power adjustable margin, wherein when the total reactive power regulation is less than or equal to the first reactive power adjustable margin, allocating the total reactive power regulation to the dynamic reactive power compensation device according to the regulation direction; otherwise, prioritizing the allocation of the total reactive power regulation to the dynamic reactive power compensation device to make the first reactive power adjustable margin zero, and then executing S3; S3: based on... According to the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system, and the adjustment direction, the first reactive power surplus adjustment amount is allocated between the wind and solar system and energy storage in the second reactive power allocation, to obtain the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage respectively. If the first reactive power adjustment amount is greater than zero, S4 is executed; the first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin; S4: According to the allocation strategy between wind power and photovoltaic in the wind and solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic and the adjustment direction, the first reactive power adjustment amount is allocated between wind power and photovoltaic in the third reactive power allocation, to obtain the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic respectively.

[0033] Based on the above technical solution, the beneficial effects of this invention are:

[0034] This invention, by acquiring the total reactive power regulation amount and direction, assumes that the SVG device has a higher priority than the wind-solar-storage system. First, based on the adjustable margin of the SVG device, the total reactive power regulation amount is preferentially allocated to the SVG device, with the remaining reactive power allocated to the wind-solar-storage system. Then, based on the priority between the wind-solar system and energy storage, the remaining reactive power is distributed between the wind-solar system or energy storage. If the wind-solar reactive power regulation amount allocated to the wind-solar system is greater than zero, it is further distributed between wind power and photovoltaic power, ultimately obtaining the reactive power regulation amounts for wind power, photovoltaic power, and energy storage respectively. In reactive power coordination control, this invention fully considers the different priorities of SVG devices, energy storage, wind power, and photovoltaic power within a combined wind-solar-storage power station. Since the priorities between the wind-solar system and energy storage, and between wind power and photovoltaic power, are determined based on the actual operating conditions of the power system, this invention can flexibly perform reactive power coordination control based on the actual operating status of various devices such as wind power, photovoltaic power, energy storage, and SVG within a combined wind-solar-storage power station, which is beneficial to the stability, reliability, and economy of the power system's grid-connected operation. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating an embodiment of the method of the present invention;

[0036] Figure 2 This is a flowchart illustrating another embodiment of the method of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0038] This invention provides a reactive power coordination control method and device for a wind-solar-storage combined power station, to solve the technical problem in the prior art that reactive power coordination control cannot be flexibly performed according to the actual operating conditions of the power system.

[0039] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] Wind and solar energy, as representatives of new energy sources, will be widely used with the construction of new power systems based on new energy sources. However, both wind and solar power generation are characterized by randomness and intermittency. Coupled with technical bottlenecks in forecasting, scheduling, and control, the independent power generation characteristics and grid-source coordination characteristics of these two new energy sources still differ significantly from conventional power sources. Chemical energy storage devices can effectively solve this problem. Therefore, the complementarity between wind, solar, and energy storage can be utilized to construct combined wind-solar-energy storage power plants, improving their grid-connected operation stability and economic efficiency. Furthermore, combined wind-solar-energy storage power plants are typically equipped with dynamic var compensators (SVG). Since combined wind-solar-energy storage power plants contain multiple reactive power control devices, a key issue to consider is the coordinated reactive power control of various power generation devices.

[0042] Please see Figure 1 An embodiment of a reactive power coordination control method for a wind-solar-storage combined power station provided by the present invention includes:

[0043] S100: Obtain the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total reactive power adjustment amount and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction.

[0044] S200: Perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, allocate the entire total reactive power adjustment to the dynamic reactive power compensation device according to the adjustment direction; otherwise, allocate the total reactive power adjustment to the dynamic reactive power compensation device first to make the first reactive power adjustable margin zero, and then execute S300.

[0045] S300: Based on the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system, and the adjustment direction, the first reactive power surplus adjustment amount is allocated between the wind and solar system and energy storage in a second reactive power distribution, respectively obtaining the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage. If the first reactive power adjustment amount is greater than zero, execute S400; the first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin.

[0046] S400: Based on the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power, and the adjustment direction, the first reactive power adjustment amount is allocated between wind power and photovoltaic power in a third reactive power distribution, thereby obtaining the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power.

[0047] In step S100, the wind-solar-storage combined power station first obtains the total reactive power regulation command and the first reactive power adjustable margin of the dynamic reactive power compensation device; wherein, the total reactive power regulation command includes the total amount of reactive power to be adjusted and the reactive power adjustment direction, and the reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction.

[0048] It is understandable that when the reactive power adjustment direction is upward, the first reactive power adjustable margin of the dynamic reactive power compensation device is the first reactive power upward adjustment margin; otherwise, the first reactive power adjustable margin of the dynamic reactive power compensation device is the first reactive power downward adjustment margin.

[0049] In step S100, the process of obtaining the first reactive power adjustable margin of the dynamic reactive power compensation device is as follows: when the adjustment direction is upward, the maximum reactive power and the current reactive power output of the dynamic reactive power compensation device need to be collected, and the first reactive power adjustable margin is the difference between the maximum reactive power and the current reactive power output; when the adjustment direction is downward, the minimum reactive power and the current reactive power output of the dynamic reactive power compensation device need to be collected, and the first reactive power adjustable margin is the difference between the current reactive power output and the minimum reactive power.

[0050] Before executing step S200, when the adjustment direction is upward, the current maximum reactive power output and reactive power of energy storage, wind power, and photovoltaic power are obtained respectively; when the adjustment direction is downward, the current minimum reactive power output and reactive power of energy storage, wind power, and photovoltaic power are obtained respectively. This is to calculate the reactive power upward adjustment margin of energy storage.

[0051] Before executing step S200, the reactive power adjustable margins for energy storage, wind power, and photovoltaic are calculated separately. Specifically, when the adjustment direction is upward, the reactive power upward adjustment margins for energy storage, wind power, and photovoltaic are obtained respectively; when the adjustment direction is downward, the reactive power downward adjustment margins for energy storage, wind power, and photovoltaic are obtained respectively. For example, when the adjustment direction is upward, only the fourth reactive power upward adjustment margin for wind power needs to be obtained, by collecting the maximum reactive power value and the current reactive power output of wind power. The fourth reactive power upward adjustment margin for wind power is the difference between the maximum reactive power value and the current reactive power output of wind power. When the adjustment direction is downward, only the fourth reactive power downward adjustment margin for wind power needs to be obtained, by collecting the minimum reactive power value and the current reactive power output of wind power. The fourth reactive power downward adjustment margin for wind power is the difference between the current reactive power output and the minimum reactive power value of wind power. The calculation methods for the second reactive power adjustable margin of energy storage and the fifth reactive power adjustable margin of photovoltaics are similar to those for wind power, and will not be repeated here.

[0052] In step S200, a first reactive power allocation is performed according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, the total reactive power adjustment is allocated to the dynamic reactive power compensation device. Otherwise, the total reactive power adjustment is preferentially allocated to the dynamic reactive power compensation device so that the first reactive power adjustable margin is zero, and then step S300 is executed.

[0053] In this embodiment, reactive power is allocated based on the first reactive power adjustable margin of the dynamic reactive power compensation device (SVG device). When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin of the SVG device, only the SVG reactive power adjustment command is issued to the SVG device, and the total reactive power adjustment is allocated to the SVG device. That is, at this time, reactive power is allocated only to the SVG device, and there is no need to allocate reactive power to the wind, solar and energy storage system. The reactive power allocation ends here.

[0054] When the total reactive power regulation exceeds the first reactive power adjustable margin of the SVG device, a full-load command is first issued to the SVG device, prioritizing the allocation of the total reactive power regulation to the dynamic reactive power compensation device to reduce the first reactive power adjustable margin to zero. Then, subsequent steps are executed to distribute the remaining portion, i.e., the first residual reactive power regulation, among the wind, solar, and energy storage systems. It can be understood that the first residual reactive power regulation is the difference between the total reactive power regulation and the first reactive power adjustable margin.

[0055] It should be noted that when the total reactive power regulation exceeds the first reactive power adjustment margin of the SVG device, a full-load command is issued to the SVG device. This means that an amount of reactive power equivalent to the first reactive power adjustment margin is taken from the total reactive power regulation and allocated to the SVG device, making the first reactive power adjustment margin of the SVG device zero after the first allocation. When the reactive power regulation direction is upward, the reactive power of the SVG device reaches its maximum reactive power value after the first allocation; when the reactive power regulation direction is downward, the reactive power of the SVG device reaches its minimum reactive power value after the first allocation.

[0056] It should be noted that the adjustability margin of a wind-solar-storage system is the sum of the adjustability margins of energy storage, wind power, and photovoltaics.

[0057] In step S300, the first reactive power surplus adjustment amount is allocated between the wind and solar system and energy storage according to the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system and the adjustment direction, so as to obtain the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of energy storage respectively. If the first reactive power adjustment amount is greater than zero, S4 is executed; wherein, the first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin.

[0058] In this embodiment, the second reactive power adjustable margin of energy storage is either the second reactive power upward adjustment margin (when adjusted upward) or the second reactive power downward adjustment margin (when adjusted downward), and the third reactive power adjustable margin of the wind and solar system is either the third reactive power upward adjustment margin (when adjusted upward) or the third reactive power downward adjustment margin (when adjusted downward). Specifically, the second reactive power upward adjustment margin is the difference between the maximum reactive power of the energy storage and the current reactive power output, and the second reactive power downward adjustment margin is the difference between the current reactive power output of the energy storage and the minimum reactive power value. The third reactive power upward adjustment margin is the difference between the maximum reactive power of the wind and solar system and the current reactive power output, and the third reactive power downward adjustment margin is the difference between the current reactive power output of the wind and solar system and the minimum reactive power value.

[0059] In the second reactive power allocation, the wind-solar-storage combined power station generates power control commands for the wind-solar system and power control commands for the energy storage device based on the allocation strategy of wind, solar and energy storage, and obtains the first reactive power regulation of the wind-solar system and the second reactive power regulation of the energy storage device respectively.

[0060] The reactive power allocation strategy of the wind-solar-storage combined power station is determined according to the priority between the wind-solar system and the energy storage: when energy storage is prioritized, only the reactive power output of the energy storage is adjusted if there is a reactive power adjustment margin, and the reactive power output of the wind-solar system is adjusted if there is no reactive power adjustment margin; when the wind-solar system is prioritized, only the reactive power output of the wind-solar system is adjusted if there is a reactive power adjustment margin, and the reactive power output of the energy storage is adjusted if there is no reactive power adjustment margin.

[0061] When the first allocation priority between the wind and solar system and energy storage is energy storage priority, and the adjustment direction is upward, the second reactive power adjustable margin is the second reactive power upward adjustment margin. The first remaining reactive power adjustment amount is compared with the second reactive power upward adjustment margin. If the first remaining reactive power adjustment amount is less than or equal to the second reactive power upward adjustment margin, it indicates that the reactive power upward adjustment margin of energy storage is sufficient. Therefore, only the reactive power output of energy storage needs to be adjusted, and the reactive power output of the wind and solar system does not need to be adjusted. In this case, the second reactive power adjustment amount of energy storage equals the first remaining reactive power adjustment amount, and the first reactive power adjustment amount of the wind and solar system is zero. Otherwise, it indicates that energy storage does not have sufficient reactive power upward adjustment margin. The first remaining reactive power adjustment amount is preferentially allocated to energy storage so that the second reactive power upward adjustment margin is zero. Then, the reactive power output of the wind and solar system is adjusted. In this case, the second reactive power adjustment amount of energy storage equals the second reactive power upward adjustment margin, and the first reactive power adjustment amount of the wind and solar system is the difference between the first remaining reactive power adjustment amount and the second reactive power upward adjustment margin.

[0062] If energy storage is prioritized and the adjustment direction is downward, the second reactive power adjustable margin is the second reactive power downward adjustment margin. The first remaining reactive power adjustment amount is compared with the second reactive power downward adjustment margin. If the first remaining reactive power adjustment amount is less than or equal to the second reactive power downward adjustment margin, it indicates that the reactive power downward adjustment margin of energy storage is sufficient. Therefore, only the reactive power output of energy storage needs to be adjusted, and the reactive power output of the wind and solar systems does not need to be adjusted. In this case, the second reactive power adjustment amount of energy storage equals the first remaining reactive power adjustment amount, and the first reactive power adjustment amount of the wind and solar systems is zero. Otherwise, it indicates that energy storage does not have sufficient reactive power downward adjustment margin. The first remaining reactive power adjustment amount is prioritized and allocated to energy storage to make the second reactive power downward adjustment margin zero. Then, the reactive power output of the wind and solar systems is adjusted. In this case, the second reactive power adjustment amount of energy storage equals the second reactive power downward adjustment margin, and the first reactive power adjustment amount of the wind and solar systems is the difference between the first remaining reactive power adjustment amount and the second reactive power downward adjustment margin.

[0063] When the first allocation priority between wind and solar systems and energy storage is wind and solar systems first, the reactive power allocation is similar to that of energy storage first, and will not be elaborated here.

[0064] In step S400, the first reactive power adjustment amount is distributed between wind power and photovoltaic power according to the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustment margin of wind power, the fifth reactive power adjustment margin of photovoltaic power and the adjustment direction, so as to obtain the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power respectively.

[0065] The power allocation strategy between wind and solar power in a wind-solar system is either a proportional allocation strategy or a priority allocation strategy. The proportional allocation strategy includes allocating reactive power between wind and solar power based on the ratio of their maximum or minimum reactive power values. The proportional allocation can be set according to site requirements. If the wind and solar outputs are comparable, the allocation is based on the ratio of their upper and lower limits. For example, if the maximum (upper limit) reactive power of a wind turbine is 60 MVar and the minimum (lower limit) is 20 Mvar, and the maximum (upper limit) reactive power of solar power is 40 MVar and the minimum (lower limit) is 10 Mvar, then when reactive power needs to be increased, the maximum reactive power ratio allocated between wind and solar power is 60:40; when reactive power needs to be decreased, the minimum reactive power ratio allocated between wind and solar power is 20:10.

[0066] The priority allocation strategy is divided into two types: wind power priority and solar power priority. When wind power is prioritized, only the reactive power output of wind power is adjusted if there is an adjustable margin, and the reactive power output of solar power is adjusted only if there is no adjustable margin. When solar power is prioritized, only the reactive power output of solar power is adjusted if there is an adjustable margin, and the reactive power output of wind power is adjusted only if there is no adjustable margin.

[0067] It should be noted that hybrid wind-solar-storage power stations can choose one of two allocation strategies (proportional allocation or priority allocation) based on application needs. When the region where the hybrid wind-solar-storage power station (new energy power station) is located has abundant wind and solar power resources, a proportional allocation strategy can be chosen based on the actual situation. When one of the wind or solar power resources has a greater advantage, a priority allocation strategy can be chosen. For example, when there is sufficient sunlight and low wind speed during the day, solar power can be prioritized; when it is cloudy during the day and the wind speed is high, wind power can be prioritized; when there is very weak sunlight and only wind at night, wind power can be prioritized.

[0068] In the third reactive power allocation, the wind-solar-storage combined power station generates power control commands for wind turbines and photovoltaic units based on the reactive power allocation strategy between wind power and photovoltaics. In other words, it ultimately generates reactive power control commands (including reactive power adjustment amount and adjustment direction) for the three devices of wind power, photovoltaics and energy storage.

[0069] The reactive power coordination control method for a combined wind-solar-storage power station provided in this invention obtains the total reactive power regulation amount and direction. It assumes that the SVG device has a higher priority than the wind-solar-storage system. First, based on the adjustable margin of the SVG device, the total reactive power regulation amount is preferentially allocated to the SVG device, and the remaining reactive power is allocated to the wind-solar-storage system. Then, based on the priority between the wind-solar system and energy storage, the remaining reactive power is allocated between the wind-solar system and energy storage. If the wind-solar reactive power regulation amount allocated to the wind-solar system is greater than zero, the wind-solar reactive power regulation amount is further allocated between wind power and photovoltaic power, ultimately obtaining the reactive power regulation amounts for wind power, photovoltaic power, and energy storage respectively. When performing reactive power coordination control, this invention fully considers the different priorities of SVG devices, energy storage, wind power, and photovoltaics within a wind-solar-storage combined power station. Since the priorities between wind and solar systems and energy storage, as well as between wind power and photovoltaics, are determined based on the actual operating conditions of the power system, this invention can flexibly perform reactive power coordination control based on the actual operating status of various devices such as wind power, photovoltaics, energy storage, and SVG within the wind-solar-storage combined power station, which is beneficial to the stability, reliability, and economy of the power system's grid-connected operation.

[0070] Please see Figure 2 The present invention also provides another embodiment of a reactive power coordination control method for a wind-solar-storage combined power station, comprising:

[0071] 1) The combined wind, solar and energy storage power station obtains the general command for reactive power regulation (including the total amount of reactive power regulation and the direction of reactive power regulation), collects the current reactive power output, maximum or minimum reactive power of the SVG device, wind, solar and energy storage in the power station, and calculates the reactive power upward or downward adjustment margin of the SVG device, wind, solar and energy storage respectively.

[0072] It should be noted that when the reactive power adjustment direction is upward, the reactive power upward adjustment margin of the corresponding device can be obtained by simply collecting the current reactive power output and maximum reactive power of the SVG device, wind, solar, and energy storage; when the reactive power adjustment direction is downward, the reactive power downward adjustment margin of the corresponding device can be obtained by simply collecting the current reactive power output and minimum reactive power of the SVG device, wind, solar, and energy storage.

[0073] Reactive power allocation is prioritized based on the reactive power adjustment margin of the SVG device. Specifically, when the reactive power adjustment command is less than the SVG device's adjustment margin, reactive power is allocated only to the SVG device; when the reactive power adjustment command is greater than the SVG device's adjustment margin, the SVG device is allowed to operate at full capacity, and the remaining portion is then allocated among wind, solar, and energy storage, with subsequent strategies executed. This ultimately yields the SVG reactive power control command and the wind-solar-energy storage reactive power control command.

[0074] 2) The wind-solar-storage combined power station selects the allocation strategy of wind, solar and energy storage according to the reactive power adjustment command of wind, solar and energy storage: when energy storage is prioritized, only the reactive power output of energy storage is adjusted when there is an adjustable margin for energy storage, and the reactive power output of wind and solar is adjusted when there is no adjustable margin for energy storage; when wind and solar are prioritized, only the reactive power output of wind and solar is adjusted when there is an adjustable margin for wind and solar, and the reactive power output of energy storage is adjusted when there is no adjustable margin for wind and solar.

[0075] 3) Based on the allocation strategy of wind, solar and energy storage, the combined wind, solar and energy storage power station generates power control commands for energy storage devices and power control commands for wind and solar systems.

[0076] 4) The wind-solar-storage combined power station calculates the power control command of the wind and solar system according to the previous steps, and at the same time collects the actual power generation, maximum reactive power and minimum reactive power of the wind and solar systems in the power station (already in step 1, can be deleted).

[0077] 5) For wind-solar-storage hybrid power plants, one of two allocation strategies (proportional allocation or priority allocation) can be selected based on application needs.

[0078] 6) For the proportional allocation strategy, the allocation is based on the upper and lower limits (maximum and minimum values) of wind and solar reactive power.

[0079] 7) The priority allocation strategy is divided into two types: wind priority and solar priority. When wind priority is applied, only the wind reactive power output is adjusted when there is an adjustable margin for wind, and the solar reactive power output is adjusted when there is no adjustable margin for wind. When solar priority is applied, only the solar reactive power output is adjusted when there is an adjustable margin for solar, and the wind reactive power output is adjusted when there is no adjustable margin for solar.

[0080] 8) Based on the wind and solar power distribution strategy, the combined wind, solar and energy storage power station generates reactive power control commands for wind turbines and photovoltaic units, which ultimately form reactive power control commands for the three devices: wind power, photovoltaics and energy storage.

[0081] Please see Figure 3The present invention also provides an embodiment of a reactive power coordination control device for a wind-solar-storage combined power station, comprising:

[0082] The initial data acquisition module 11 is used to acquire the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total amount of reactive power adjustment to be adjusted and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction.

[0083] The first reactive power allocation module 22 is used to perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, the total reactive power adjustment is allocated to the dynamic reactive power compensation device according to the adjustment direction; otherwise, the total reactive power adjustment is preferentially allocated to the dynamic reactive power compensation device to make the first reactive power adjustable margin zero, and then the second reactive power allocation module is executed.

[0084] The second reactive power allocation module 33 is used to perform a second reactive power allocation between the wind and solar system and the energy storage system based on the first allocation priority between the wind and solar system and the energy storage system, the second reactive power adjustable margin of the energy storage system, the third reactive power adjustable margin of the wind and solar system and the adjustment direction, so as to obtain the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage system respectively. If the first reactive power adjustment amount is greater than zero, the third reactive power allocation module is executed. The first reactive power remaining adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin.

[0085] The third reactive power allocation module 44 is used to perform a third reactive power allocation between wind power and photovoltaic power according to the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power, and the adjustment direction, so as to obtain the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power respectively.

[0086] This embodiment first allocates reactive power based on SVG, wind-solar-storage, and reactive power (RSS). Then, it adjusts the reactive power output of wind-solar-storage based on wind and solar power, and finally, it adjusts the reactive power output of wind-solar pairs based on wind priority and solar priority. This invention can flexibly coordinate and control the reactive power of various devices such as wind power, photovoltaics, energy storage, and SVG within a combined wind-solar-storage power station.

[0087] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0088] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or electrical connection shown or discussed between each other can be through some interfaces; the indirect coupling or electrical connection between devices or units can be electrical, mechanical, or other forms.

[0089] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0090] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0091] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0092] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reactive power coordination control method for a wind-solar-storage combined power station, characterized in that, include: S1: Obtain the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total reactive power adjustment amount and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction. S2: Perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, allocate the entire total reactive power adjustment to the dynamic reactive power compensation device according to the adjustment direction; otherwise, allocate the total reactive power adjustment to the dynamic reactive power compensation device first to make the first reactive power adjustable margin zero, and then execute S3. S3: Based on the first allocation priority between the wind and solar system and energy storage, the second reactive power adjustable margin of energy storage, the third reactive power adjustable margin of the wind and solar system, and the adjustment direction, the first reactive power surplus adjustment amount is allocated between the wind and solar system and energy storage in a second reactive power distribution, respectively obtaining the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage. If the first reactive power adjustment amount is greater than zero, proceed to S4; the first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin. S4: Based on the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power, and the adjustment direction, the first reactive power adjustment amount is allocated between wind power and photovoltaic power in a third reactive power distribution, thereby obtaining the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power.

2. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, The allocation strategy between wind power and photovoltaic power in the wind-solar system is as follows: Allocation strategy based on proportion or allocation strategy based on priority.

3. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 2, characterized in that, The proportional allocation strategy includes: When the adjustment direction is upward, the reactive power between wind power and photovoltaic power is allocated according to the ratio of the maximum reactive power between wind power and photovoltaic power.

4. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 2, characterized in that, The proportional allocation strategy includes: When the adjustment direction is downward, the reactive power between wind power and photovoltaic power is allocated according to the minimum reactive power ratio between wind power and photovoltaic power.

5. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, When the reactive power adjustment direction is upward, the reactive power adjustable margin of the dynamic reactive power compensation device is the first reactive power upward adjustment margin; otherwise, the reactive power adjustable margin of the dynamic reactive power compensation device is the first reactive power downward adjustment margin.

6. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, When the reactive power adjustment direction is upward, the second reactive power adjustable margin of the energy storage is the second reactive power upward adjustment margin; otherwise, the second reactive power adjustable margin of the energy storage is the second reactive power downward adjustment margin.

7. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, The steps preceding step S2 also include: When the adjustment direction is upward, the current reactive power output and maximum reactive power of energy storage, wind power, and photovoltaic power are obtained respectively. When the adjustment direction is downward, the current reactive power output and minimum reactive power of energy storage, wind power, and photovoltaic power are obtained respectively.

8. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, When the reactive power adjustment direction is upward, the fourth reactive power adjustable margin of the wind power is the difference between the maximum reactive power of the wind power and the current reactive power output. Otherwise, the fourth reactive power adjustable margin of the wind power is the difference between the current reactive power output of the wind power and the minimum reactive power.

9. The reactive power coordination control method for a wind-solar-storage combined power station according to claim 1, characterized in that, When the reactive power adjustment direction is upward, the fifth reactive power adjustable margin of the photovoltaic is the difference between the maximum reactive power of the photovoltaic and the current reactive power output. Otherwise, the fifth reactive power adjustable margin of the photovoltaic system is the difference between the current reactive power output of the photovoltaic system and the minimum reactive power.

10. A reactive power coordination control device for a wind-solar-storage combined power station, characterized in that, include: The initial data acquisition module is used to acquire the total reactive power adjustment command and the first reactive power adjustable margin of the dynamic reactive power compensation device. The total reactive power adjustment command includes the total reactive power adjustment amount and the reactive power adjustment direction. The reactive power adjustment direction includes the upward adjustment direction and the downward adjustment direction. The first reactive power allocation module is used to perform a first reactive power allocation according to the total reactive power adjustment command and the first reactive power adjustable margin. When the total reactive power adjustment is less than or equal to the first reactive power adjustable margin, the total reactive power adjustment is allocated to the dynamic reactive power compensation device according to the adjustment direction; otherwise, the total reactive power adjustment is preferentially allocated to the dynamic reactive power compensation device to make the first reactive power adjustable margin zero, and then the second reactive power allocation module is executed. The second reactive power allocation module is used to perform a second reactive power allocation between the wind and solar system and the energy storage based on the first allocation priority between the wind and solar system and the energy storage, the second reactive power adjustable margin of the energy storage, the third reactive power adjustable margin of the wind and solar system and the adjustment direction, so as to obtain the first reactive power adjustment amount of the wind and solar system and the second reactive power adjustment amount of the energy storage respectively. If the first reactive power adjustment amount is greater than zero, the third reactive power allocation module is executed. The first reactive power surplus adjustment amount is the difference between the total reactive power adjustment amount and the first reactive power adjustable margin; The third reactive power allocation module is used to perform a third reactive power allocation between wind power and photovoltaic power according to the allocation strategy between wind power and photovoltaic power in the wind-solar system, the fourth reactive power adjustable margin of wind power, the fifth reactive power adjustable margin of photovoltaic power and the adjustment direction, so as to obtain the third reactive power adjustment amount of wind power and the fourth reactive power adjustment amount of photovoltaic power respectively.

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