Improved droop curve dynamic voltage regulation method and system with closed-loop verification

Abstract

The application discloses a kind of first monitoring and grid point voltage and station reactive power, reactive power output value is calculated by reactive power voltage regulating coefficient, and instruction is issued to power station reactive power equipment;Again, real-time voltage and station reactive power of re-monitoring grid point, real-time voltage is in voltage regulation dead zone, then dynamic voltage regulating reaches target value, no longer carries out voltage regulating;If grid point voltage is still outside grid point voltage regulation dead zone, then according to the real-time voltage and station reactive power of monitoring, correct reactive power voltage regulating coefficient, with corrected reactive power voltage regulating coefficient, carry out dynamic voltage regulating again by droop curve, until voltage regulation is in dead zone range.The improved droop regulation of closed loop verification retains the rapidity of open loop droop regulation, and also has the accuracy of closed loop regulation.In the process of voltage regulating, by controlling the number of closed loop feedback, the problem of adjustment oscillation can be effectively prevented to solve the problem of existing dynamic voltage regulating not in place.

Description

Technical Field

[0001] This invention relates to grid connection of new energy power generation, specifically to an improved dynamic voltage regulation method and system for closed-loop verification of droop curves. Background Technology

[0002] Currently, new energy power generation is developing rapidly and continuously, striving to build a clean, low-carbon, safe, and efficient energy system and a new power system based on new energy sources. As the penetration rate of new energy sources continues to increase, the power system will transform into a complex system dominated by new power electronic equipment.

[0003] However, the timeliness and volatility of new energy power generation (photovoltaic power generation, wind power generation, etc.) can affect the stability of power system operation, leading to a decline in power quality. One of the key factors affecting power quality is grid voltage fluctuation. Therefore, how to solve the problem of voltage fluctuation caused by large-scale grid connection of new energy sources has become an urgent problem to be solved.

[0004] To address the voltage fluctuation issues caused by large-scale grid connection of renewable energy sources, renewable energy power plants are required to have dynamic voltage regulation capabilities. However, current technologies for dynamic voltage regulation in renewable energy power plants mostly follow... Figure 1 The control mode shown in the traditional dynamic reactive power voltage regulation droop curve often suffers from inadequate voltage regulation. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned shortcomings, this invention provides an improved dynamic voltage regulation method and system for droop curves with fast and accurate closed-loop verification.

[0006] Technical solution: To solve the above problems, this invention adopts an improved dynamic voltage regulation method based on closed-loop verification of the droop curve, comprising the following steps:

[0007] Step 1: Obtain the real-time voltage at the grid connection point of the new energy power generation system and the reactive power of the new energy power generation system;

[0008] Step 2, after determining that the acquired real-time voltage is outside the target voltage range

[0009] At that time, the reactive power adjustment amount of the new energy power generation system is calculated based on the droop coefficient of reactive power regulation, and the reactive power output of the equipment in the new energy power generation system is adjusted according to the calculated adjustment amount.

[0010] Step 3: Obtain the voltage at the grid connection point after the reactive power output of the new energy power generation system has been regulated;

[0011] If the adjusted real-time voltage is within the target voltage range, the droop coefficient is corrected based on the adjusted real-time voltage and the reactive power of the new energy power generation system. The adjustment amount of the reactive power of the new energy power generation system is calculated based on the corrected droop coefficient, and the reactive power output of the equipment in the new energy power generation system is adjusted based on the calculated adjustment amount. Then, return to step 1.

[0012] Furthermore, in step 2, the target voltage range is (U N -△U)≤U≤(U N +△U), where U is the real-time voltage at the grid connection point, U N The voltage at the grid connection point is the rated voltage, and ΔU is the dead zone for voltage adjustment at the grid connection point. The dead zone for voltage adjustment at the grid connection point is within ±0.5% to ±2% of the rated voltage.

[0013] Furthermore, the formula for calculating the reactive power output Q of the equipment in the new energy power generation system in step 2 is as follows:

[0014]

[0015] Among them, Q A Q represents the upper limit of reactive power output from equipment in a new energy power generation system. B U is the lower limit of reactive power output from equipment in a new energy power generation system. low U is the lower limit of the grid connection point voltage regulation. high Q0 represents the upper limit of the grid connection point voltage regulation, Q0 represents the current output reactive power of the equipment in the new energy power generation system, and K represents the droop coefficient of reactive power regulation.

[0016] Furthermore, the correction formula for the droop coefficient in step 3 is as follows:

[0017]

[0018] Where Q′ represents the reactive power output of the regulated new energy power generation system equipment, and U′ represents the regulated grid connection point voltage. Initially, the droop coefficient K of the reactive power voltage regulation ranges from 2 to 15.

[0019] This invention also employs an improved dynamic voltage regulation system for droop curves with closed-loop verification, comprising a data acquisition module, a calculation module, and an adjustment module, wherein:

[0020] The data acquisition module is used to acquire the real-time voltage at the grid connection point of the new energy power generation system and the power distribution network, as well as the reactive power of the new energy power generation system.

[0021] The calculation module is used to calculate the adjustment amount of reactive power of the new energy power generation system based on the droop coefficient of reactive power voltage regulation when it is determined that the acquired real-time voltage is within the target voltage range; it is also used to correct the droop coefficient based on the real-time voltage after adjustment by the adjustment module and the reactive power of the new energy power generation system.

[0022] The adjustment module is used to adjust the reactive power output of the equipment in the new energy power generation system according to the calculated adjustment amount.

[0023] Beneficial effects: Compared with the prior art, the significant advantage of this invention is the use of an improved droop adjustment with closed-loop verification, which retains the speed of open-loop droop adjustment while also possessing the accuracy of closed-loop adjustment. During voltage regulation, by controlling the number of closed-loop feedback cycles, the problem of regulation oscillation can be effectively prevented, thus solving the problem of inadequate voltage regulation in existing dynamic voltage regulation. Attached Figure Description

[0024] Figure 1 The figure shows the dynamic reactive power voltage regulation droop curve in the prior art;

[0025] Figure 2 The flowchart shown is a dynamic voltage regulation method of the present invention;

[0026] Figure 3 The figure shows the dynamic reactive power voltage regulation droop curve in this invention;

[0027] Figure 4 The diagram shows a fast power control device deployed in series with the EMS in a wind farm station, applying the voltage regulation system of this invention.

[0028] Figure 5 The diagram shows a fast power control device deployed in parallel with the EMS in a wind farm, applying the voltage regulation system of this invention.

[0029] Figure 6 The diagram shows a fast power control device deployed in series with the EMS in a photovoltaic power plant, applying the voltage regulation system of this invention.

[0030] Figure 7 The diagram shows a fast power control device deployed in parallel with the EMS in a photovoltaic power plant, applying the voltage regulation system of this invention. Detailed Implementation

[0031] Example 1

[0032] like Figure 2 As shown in this embodiment, an improved dynamic voltage regulation method for closed-loop verification based on droop curves includes the following steps:

[0033] (1) Obtain the real-time voltage at the grid connection point of the new energy power generation system (wind farm or photovoltaic power generation station, etc.) and the reactive power of the new energy power generation system;

[0034] (2) Determine whether the real-time voltage obtained is within the target voltage range. If the real-time voltage is outside the target voltage range, proceed to step (3). If the real-time voltage is within the target voltage range, end the adjustment.

[0035] (3) Calculate the reactive power adjustment amount of the new energy power generation system based on the droop coefficient of reactive power regulation. When the real-time voltage at the grid connection point is less than the target voltage range and enters the operating zone, adjust the reactive power source equipment of the entire station to increase the reactive power output. The upper limit of reactive power output is Q. A When the real-time voltage at the grid connection point exceeds the target voltage range and enters the operating zone, the reactive power source equipment of the entire substation is adjusted to reduce reactive power output. The lower limit of reactive power output is Q. B The target voltage range is (U N -△U)≤U≤(U N +△U), where U is the real-time voltage at the grid connection point, U N ΔU is the rated voltage at the grid connection point, and ΔU is the dead zone for voltage regulation at the grid connection point.

[0036] The formula for calculating the reactive power output Q of equipment in a new energy power generation system is as follows:

[0037]

[0038] Among them, Q A Q represents the upper limit of reactive power output from equipment in a new energy power generation system. B U is the lower limit of reactive power output from equipment in a new energy power generation system. low U is the lower limit of the grid connection point voltage regulation. high Q0 represents the upper limit of the grid connection point voltage regulation, Q0 represents the current output reactive power of the equipment in the new energy power generation system, and K represents the droop coefficient of reactive power regulation.

[0039] The droop coefficient K of reactive power regulation should be set reasonably according to the capacity of the reactive power compensation device of the new energy power station and the actual situation of the local power grid. The general range is 2 to 15, and the typical value is 6.

[0040] Reactive voltage regulation should be set with a voltage dead zone for reactive voltage droop control according to the requirements of the local power grid. The dead zone range is generally set between ±0.5% and ±2% of the rated voltage.

[0041] Adjust the reactive power output of equipment in the new energy power generation system according to the calculated adjustment amount;

[0042] (4) Obtain the voltage at the grid connection point after the reactive power output regulation of the new energy power generation system;

[0043] (5) Determine whether the adjusted real-time voltage is within the target voltage range. If the real-time voltage is outside the target voltage range, proceed to step (6). If the real-time voltage is within the target voltage range, end the adjustment.

[0044] (6) Correct the droop coefficient based on the adjusted real-time voltage and the reactive power of the new energy power generation system. Calculate the adjustment amount of the reactive power of the new energy power generation system based on the corrected droop coefficient, and adjust the reactive power output of the equipment in the new energy power generation system according to the calculated adjustment amount. Return to step (2). The correction formula for the droop coefficient is:

[0045]

[0046] Where Q′ represents the reactive power output of the regulated new energy power generation system equipment, and U′ represents the regulated grid connection point voltage. This voltage regulation method retains the speed of open-loop droop regulation while also possessing the accuracy of closed-loop regulation. During the voltage regulation process, controlling the number of closed-loop feedback cycles effectively prevents regulation oscillations.

[0047] When performing dynamic reactive power voltage regulation at a power station, the grid connection point voltage U and the station's reactive power Q are monitored first. The reactive power output value is calculated from the theoretical grid connection point dynamic reactive power voltage regulation coefficient K, and the command is sent to the power station's reactive power source equipment. Then, the real-time grid connection point voltage U and the station's reactive power Q are monitored again, and compared with the grid connection point rated voltage U. N Compare. If (U) N -△U)≤U≤(U N If the voltage U is +ΔU, then the dynamic voltage regulation reaches the target value and no further voltage regulation is required. If the grid connection point voltage U is still outside the dead zone of the grid connection point voltage regulation, then the reactive power voltage regulation coefficient K is corrected based on the monitored real-time voltage U and the reactive power Q of the power station. The corrected reactive power voltage regulation coefficient is then used for dynamic voltage regulation using the droop curve until the voltage is regulated to the dead zone range. During the dynamic voltage regulation process, attention should be paid to the upper limit of the reactive power regulation Q of the power station. A and the lower limit of reactive power regulation Q B If the calculated reactive power command exceeds the upper limit Q A or below the lower limit Q B Then the output reactive power command should be Q. A Or Q B .

[0048] like Figure 3 As shown, the monitored grid connection point voltage is U′, and the current reactive power of the power station is Q0. First, the voltage is adjusted according to the theoretical grid connection point dynamic voltage regulation coefficient K, and the reactive power command to be issued to the power station is calculated to be Q′. When the reactive power of the power station is adjusted to Q′, the grid connection point voltage is remeasured to U″. Then, the reactive power voltage regulation coefficient K should be corrected to (Q′-Q0) / [U″-(U N-△U)], based on the corrected reactive power voltage regulation coefficient, dynamic voltage regulation is performed again, and the power station should issue a reactive power command of Q″.

[0049] Example 2

[0050] This embodiment presents an improved dynamic voltage regulation system for droop curves with closed-loop verification, comprising a data acquisition module, a judgment module, a calculation module, and an adjustment module, wherein:

[0051] The data acquisition module is used to acquire the real-time voltage at the grid connection point of the new energy power generation system and the reactive power of the new energy power generation system.

[0052] The judgment module is used to determine whether the acquired real-time voltage is within the target voltage range;

[0053] The calculation module is used to calculate the adjustment amount of reactive power of the new energy power generation system based on the droop coefficient of reactive power voltage regulation; it is also used to correct the droop coefficient based on the real-time voltage after adjustment by the adjustment module and the reactive power of the new energy power generation system.

[0054] The adjustment module is used to adjust the reactive power output of the equipment in the new energy power generation system according to the calculated adjustment amount.

[0055] The regulation system is installed on the fast power control device of the new energy power station and deployed in the secondary grid of the new energy power station. Its deployment method is generally divided into two types: serial and parallel.

[0056] 1. Wind farm

[0057] The wind farm's EMS (Energy Management System) is deployed at the station control layer. It receives dispatch instructions via remote starters, sends reactive power commands to the wind turbine energy management system, and then the wind turbine energy management system issues detailed commands to each wind turbine. For example... Figure 4 The fast power control device at the renewable energy power plant is deployed serially with the EMS (Energy Management System). Besides implementing dynamic reactive power voltage regulation, the device also needs to forward reactive power commands sent by the EMS. For example... Figure 5 The device and EMS are deployed in parallel. When the EMS sends a reactive power command to the wind turbine energy management system, the device receives the reactive power command and blocks the command. When the grid connection point voltage is detected to enter the dynamic reactive power voltage regulation range, the device sends a signal to block the EMS and sends a reactive power command to the wind turbine energy management system. When the dynamic reactive power voltage regulation ends, the device sends an unlock signal to the EMS, and the EMS continues to send reactive power commands to the wind turbine energy management system. At this time, the device blocks the commands it sends.

[0058] 2. Photovoltaic power station

[0059] The EMS (Electronic Management System) of a photovoltaic power plant is deployed at the station control layer. It receives dispatch instructions via remote starters and distributes them to various communication management units of the photovoltaic array. For example... Figure 6During dynamic reactive power regulation, the fast power control device at the renewable energy power plant issues reactive power commands to the EMS, which then forwards them to the photovoltaic communication management unit. For example... Figure 7 The device and EMS are deployed in parallel. When the grid connection point voltage is within the normal range, the EMS sends steady-state commands to both the photovoltaic communication management unit and the fast power control device, while the device blocks its own commands. When the grid connection point voltage enters the dynamic reactive power regulation range, the fast power control device sends a signal to the EMS to block its steady-state commands and simultaneously sends reactive power commands to the photovoltaic communication management unit. When the dynamic reactive power regulation ends, the device sends a signal to the EMS to release the steady-state command blocking and simultaneously blocks its own commands.

[0060] Based on the same inventive concept, in one embodiment of the present invention, a storage medium is also provided, specifically a computer-readable storage medium, which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for analyzing the impact of user-side energy management system access on the distribution network in the above embodiment.

[0061] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0062] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0063] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0064] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. An improved dynamic voltage adjustment method for droop curves in closed-loop verification, characterized in that, Includes the following steps: Step 1: Obtain the real-time voltage at the grid connection point of the new energy power generation system and the reactive power of the new energy power generation system; Step 2: When it is determined that the acquired real-time voltage is outside the target voltage range, calculate the adjustment amount of reactive power of the new energy power generation system according to the droop coefficient of reactive power regulation, and adjust the reactive power output of the equipment in the new energy power generation system according to the calculated adjustment amount. Step 3: Obtain the real-time voltage at the grid connection point after adjusting the reactive power output of the new energy power generation system; if the adjusted real-time voltage is outside the target voltage range, correct the droop coefficient based on the adjusted real-time voltage and the reactive power of the new energy power generation system, calculate the adjustment amount of the reactive power of the new energy power generation system based on the corrected droop coefficient, and adjust the reactive power output of the equipment in the new energy power generation system based on the calculated adjustment amount, then return to Step 1.

2. The voltage regulation method according to claim 1, characterized in that, In step 2, the target voltage range is (U N -△U) ≤ U ≤ (U N +△U), where U is the real-time voltage at the grid connection point, U N ΔU is the rated voltage at the grid connection point, and ΔU is the dead zone for voltage regulation at the grid connection point.

3. The voltage regulation method according to claim 2, characterized in that, The dead zone range of the grid connection point voltage adjustment is between ±0.5% and ±2% of the rated voltage.

4. The voltage regulation method according to claim 2, characterized in that, The formula for calculating the reactive power Q output by the equipment in the new energy power generation system in step 2 is as follows: Among them, Q A Q represents the upper limit of reactive power output from equipment in a new energy power generation system. B U is the lower limit of reactive power output from equipment in a new energy power generation system. low U is the lower limit of the grid connection point voltage regulation. high Q0 represents the upper limit of the grid connection point voltage regulation, Q0 represents the current output reactive power of the equipment in the new energy power generation system, and K represents the droop coefficient of reactive power regulation.

5. The voltage regulation method according to claim 4, characterized in that, The correction formula for the droop coefficient in step 3 is as follows: in, For the reactive power output of the adjusted new energy power generation system equipment, This refers to the adjusted grid connection point voltage.

6. The voltage regulation method according to claim 5, characterized in that, Initially, the droop coefficient K of the reactive power voltage regulation ranges from 2 to 15.

7. An improved droop curve dynamic voltage regulation system with closed-loop verification, characterized in that, It includes a data acquisition module, a calculation module, and an adjustment module, among which: The data acquisition module is used to acquire the real-time voltage at the grid connection point of the new energy power generation system and the reactive power of the new energy power generation system. The calculation module is used to calculate the adjustment amount of reactive power of the new energy power generation system based on the droop coefficient of reactive power voltage regulation when it is determined that the acquired real-time voltage is outside the target voltage range; it is also used to correct the droop coefficient based on the real-time voltage after adjustment by the adjustment module and the reactive power of the new energy power generation system. The adjustment module is used to adjust the reactive power output of the equipment in the new energy power generation system according to the calculated adjustment amount.

8. The voltage regulating system according to claim 7, characterized in that, The correction formula for the droop coefficient in the calculation module is as follows: in, For the reactive power output of the adjusted new energy power generation system equipment, The adjusted grid connection point voltage is given, Q0 represents the current reactive power output of the equipment in the new energy power generation system, and U... N ΔU is the rated voltage at the grid connection point, and ΔU is the dead zone for voltage regulation at the grid connection point.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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