Method and device for determining operation mode of new energy station

Abstract

The invention provides a new energy station operation mode determination method and device, and relates to the technical field of new energy power system monitoring, and the method comprises the steps: carrying out the reactive power disturbance of a new energy station, and obtaining a power disturbance response result, which comprises an amplitude achievement rate and a response achievement duration; and determining the operation mode of the new energy station according to the amplitude achievement rate and the response achievement duration. According to the invention, the operation mode of the new energy station can be accurately and rapidly determined.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy power system monitoring, and particularly to a method and device for determining the operation mode of a new energy power station. Background Art

[0002] The proportion of installed capacity of new energy sources such as wind power and photovoltaic power continues to rise. Flexible DC transmission (Voltage SourceConverter based High Voltage Direct Current Transmission, VSC-HVDC) has become the core technology for large-scale external transmission of new energy due to its flexible reactive power regulation ability and network-forming characteristics.

[0003] According to the report of the International Energy Agency, 45% of the new energy power stations globally have adopted the combined transmission scheme of "flexible DC + AC line". While such hybrid systems improve the transmission capacity and flexibility, they also bring challenges in identifying the operation mode: the power transmission path (pure DC, parallel AC-DC) and the grid-connected and off-grid states of the new energy power station directly affect the system stability control strategy. Therefore, an effective solution is urgently needed to solve the above problems. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method and device for determining the operation mode of a new energy power station.

[0005] The present invention provides a method for determining the operation mode of a new energy power station, including: Performing reactive power disturbance on the new energy power station to obtain a power disturbance response result, where the power disturbance response result includes an amplitude achievement rate and a response achievement duration; Determining the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

[0006] According to the method for determining the operation mode of a new energy power station provided by the present invention, the performing reactive power disturbance on the new energy power station to obtain a power disturbance response result includes: Adopting a ramp injection method to inject disturbance reactive power at a set slope on the reference reactive power in the voltage control link of the flexible DC converter transformer and lasting for a first disturbance duration; Monitoring the actual value of the reactive power corresponding to the flexible DC converter transformer; Determining the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual value of the reactive power, and the disturbance reactive power.

[0007] A method for determining the operation mode of a new energy power station according to the present invention. Determining the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual reactive power value, and the disturbance reactive power includes: Calculating the sum of the reference reactive power and the disturbance reactive power to obtain the superimposed reactive power; Determining the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate; Obtaining the first time when the disturbance reactive power is injected, and determining the second time when the actual reactive power value reaches the superimposed reactive power from the steady-state reactive power; Determining the time interval between the first time and the second time as the response achievement duration.

[0008] A method for determining the operation mode of a new energy power station according to the present invention. Determining the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration includes: Judging whether the first condition corresponding to the pure DC operation mode is satisfied, where the first condition is that the amplitude achievement rate is greater than the achievement rate threshold and the response achievement duration is less than the achievement duration threshold; If not, determining the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, performing a voltage disturbance on the new energy power station to obtain a voltage disturbance response result, where the voltage disturbance response result includes a voltage overshoot and a voltage steady-state error; determining the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error.

[0009] A method for determining the operation mode of a new energy power station according to the present invention. Performing a voltage disturbance on the new energy power station to obtain a voltage disturbance response result includes: Injecting a disturbance voltage on the reference voltage in the voltage control link of the flexible DC converter transformer and lasting for a second disturbance duration; Monitoring the actual voltage value corresponding to the flexible DC converter transformer; Determining the voltage overshoot and the voltage steady-state error according to the reference voltage, the disturbance voltage, and the actual voltage value.

[0010] A method for determining the operation mode of a new energy power station according to the present invention. Determining the voltage overshoot and the voltage steady-state error according to the reference voltage, the disturbance voltage, and the actual voltage value includes: Calculating the sum of the reference voltage and the disturbance voltage to obtain the superimposed voltage; Determining the ratio of the actual voltage value exceeding the superimposed voltage as the voltage overshoot; Determine the deviation between the reference voltage and the superimposed voltage as the voltage steady-state error.

[0011] According to a method for determining an operation mode of a new energy power station provided by the present invention, determining the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error includes: Judge whether the second condition corresponding to the pure DC operation mode is satisfied, where the second condition is that the voltage overshoot is less than the overshoot threshold and the voltage steady-state error is less than the steady-state error threshold; If not, determine the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, perform a frequency disturbance on the new energy power station to obtain a frequency disturbance response result, where the frequency disturbance response result includes a frequency oscillation rate and a frequency tracking accuracy; determine the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy.

[0012] According to a method for determining an operation mode of a new energy power station provided by the present invention, performing a frequency disturbance on the new energy power station to obtain a frequency disturbance response result includes: Inject a disturbance frequency at the reference frequency in the frequency control link of the flexible DC converter transformer; Monitor the frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance stabilizes; Determine the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the disturbance frequency.

[0013] According to a method for determining an operation mode of a new energy power station provided by the present invention, determining the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the disturbance frequency includes: Calculate the sum of the reference frequency and the disturbance frequency to obtain a superimposed frequency; Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy; Extract the oscillation amplitude in a set frequency band through the fast Fourier transform algorithm to determine the frequency oscillation rate.

[0014] According to a method for determining an operation mode of a new energy power station provided by the present invention, determining the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy includes: Judge whether the third condition corresponding to the pure DC operation mode is satisfied, where the third condition is that the frequency oscillation rate is less than the oscillation rate threshold and the frequency tracking accuracy is less than the accuracy threshold; If not, determine that the operation mode of the new energy power station is the AC-DC hybrid operation mode; If so, determine that the operation mode of the new energy power station is the pure DC operation mode.

[0015] According to a method for determining the operation mode of a new energy power station provided by the present invention, before performing reactive power disturbance on the new energy power station to obtain a power disturbance response result, it further includes: Obtain grid dispatching information, where the grid dispatching information includes at least one of a new energy operation mode instruction, an AC switch state, and protection action behavior information; Based on the grid dispatching information, determine the operation mode of the new energy power station; If the determination fails, execute the steps before performing reactive power disturbance on the new energy power station to obtain a power disturbance response result.

[0016] The present invention also provides a device for determining the operation mode of a new energy power station, including: A disturbance module configured to perform reactive power disturbance on the new energy power station to obtain a power disturbance response result, where the power disturbance response result includes an amplitude achievement rate and a response achievement duration; A determination module configured to determine the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

[0017] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where when the processor executes the computer program, it implements the method for determining the operation mode of a new energy power station as described in any one of the above.

[0018] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the method for determining the operation mode of a new energy power station as described in any one of the above.

[0019] The present invention also provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the method for determining the operation mode of a new energy power station as described in any one of the above.

[0020] The method and device for determining the operation mode of a new energy station provided by the present invention perform reactive power disturbance on the new energy station to obtain a power disturbance response result, wherein the power disturbance response result includes an amplitude achievement rate and a response achievement time; and the operation mode of the new energy station is determined according to the amplitude achievement rate and the response achievement time. Through active on-grid and off-grid monitoring of the new energy station, the operation mode of the new energy station can be determined accurately and quickly, solving the problem that the speed and accuracy of model simulation calculation cannot be taken into account when the new energy station has AC fault external characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the power grid topology of the scenario of AC / DC combined transmission of new energy stations provided by the present invention.

[0023] Figure 2 It is a flow chart of the method for determining the operation mode of a new energy station provided by the present invention.

[0024] Figure 3 It is a schematic diagram of disturbance injection into the flexible DC converter transformer provided by the present invention.

[0025] Figure 4 It is a reactive power response waveform diagram of the new energy station grid connection point under pure DC operation mode provided by the present invention.

[0026] Figure 5 It is a reactive power response waveform diagram of the new energy station grid connection point under the AC / DC hybrid operation mode provided by the present invention.

[0027] Figure 6 It is a voltage response waveform diagram of the new energy station grid connection point provided by the present invention under a pure DC operation mode.

[0028] Figure 7 It is a voltage response waveform diagram of the new energy station grid connection point provided by the present invention in an AC / DC hybrid operation mode.

[0029] Figure 8 It is a waveform diagram of the frequency response and power response of the new energy station grid connection point provided by the present invention in a pure DC operation mode.

[0030] Figure 9It is a waveform diagram of the frequency response and power response of the grid connection point of the new energy power station provided by the present invention under the AC-DC hybrid operation mode.

[0031] Figure 10 It is a schematic structural diagram of the device for determining the operation mode of the new energy power station provided by the present invention.

[0032] Figure 11 It is a schematic structural diagram of the electronic device provided by the present invention. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] The following combines Figures 1 - 11 to describe the method and device for determining the operation mode of the new energy power station of the present invention.

[0035] First, a brief description is made on the relevant content involved in the present invention.

[0036] Existing research shows that the dynamic characteristics of AC-DC hybrid systems present significant differences: pure DC transmission scenario: the flexible DC converter station is the only voltage source, and its reactive power regulation response is fast and the overshoot is small. In the AC-DC combined transmission scenario, when the AC line is in parallel with the flexible DC, the system inertia increases, resulting in a delay in the reactive power response and obvious oscillations. In the off-grid island scenario, the system's frequency self-regulation ability is weak, and small-frequency disturbances will cause continuous deviation. The flexible DC system with the ability to form a grid can independently establish voltage and frequency without the support of a synchronous power source and is suitable for weak grid or island scenarios. The limitations of AC lines, affected by the cable capacitance effect, long-distance AC power transmission has a problem of reactive power surplus and poor fault ride-through ability. The necessity of hybrid transmission, the flexible DC undertakes the base load transmission, and the AC line serves as a backup path or a local power adjustment channel, but the dynamic coupling between the two leads to the prominent problem of unobservability of the power transmission path. The reactive power reverse regulation effect of the AC line will offset the reactive power disturbance response of the flexible DC and cover up the true power transmission path information. However, the existing technology fails to effectively integrate multi-dimensional dynamic characteristics such as reactive power, voltage, and frequency, resulting in a single judgment basis or difficulty in obtaining operation mode information.

[0037] The flexible DC has the ability to form a grid, and its control instructions can actively inject tiny additional instructions, which can not only stimulate the system's dynamic response but also avoid impacting the stable operation of the new energy power station.

[0038] The method for determining the operation mode of a new energy power station provided in the embodiments of the present invention is applied to the following scenario of the new energy power station transmitting power through AC-DC hybrid transmission.

[0039] Refer to Figure 1 , Figure 1 which is a schematic diagram of the power grid topology of the scenario of the new energy power station transmitting power through AC-DC hybrid transmission provided by the present invention: The new energy power station includes multiple photovoltaic power generation units, multiple wind power generation units, and an AC transformer corresponding to each power generation unit (photovoltaic power generation unit and wind power generation unit). The new energy power station transmits power through a flexible DC converter transformer (VSC, Voltage Source Converter) and an AC system (Grid_1). The photovoltaic power generation units and wind power generation units raise the voltage to 330 kV through two-stage AC transformers (primary AC transformer and secondary AC transformer), and are connected to the ±400 kV (kV) VSC through circuit breakers K1 and K2, electrical quantity measurement points, and transformers. The AC system Grid_1 is connected to the new energy power station through circuit breaker K0 and a transformer. Among them, the rated capacity of the new energy power station is 200 megawatts (MW), and the rated capacity of the VSC is 500 MW.

[0040] Figure 2 which is a schematic flowchart of the method for determining the operation mode of the new energy power station provided by the present invention. As Figure 2 shown, the method includes the following: Step 201: Perform reactive power perturbation on the new energy power station to obtain a power perturbation response result, where the power perturbation response result includes an amplitude achievement rate and a response achievement duration.

[0041] Specifically, the amplitude achievement rate refers to the ratio of the steady-state reactive power (reference reactive power Q ref ) to the total reactive power. The response achievement duration refers to the time from injecting the reactive power perturbation to the stabilization of the reactive power.

[0042] In practical applications, reactive power perturbation injection can be performed on the new energy power station: Inject a set amplitude of perturbation reactive power ΔQ ref to the new energy power station side, observe the actual value of the reactive power at the connection point of the flexible DC converter transformer, and calculate the amplitude achievement rate η Q and the response achievement duration T Q .

[0043] Step 202: Determine the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

[0044] In practical applications, when performing reactive power perturbation injection on the new energy power station to obtain the amplitude achievement rate η Q and the response achievement duration T QAfter that, the response analysis is performed, that is, the amplitude achievement rate η Q and response time T Q Analyze and get the operation mode of new energy stations.

[0045] The method for determining the operation mode of a new energy station provided by the present invention performs reactive power disturbance on the new energy station to obtain a power disturbance response result, wherein the power disturbance response result includes an amplitude achievement rate and a response achievement time; and the operation mode of the new energy station is determined according to the amplitude achievement rate and the response achievement time. By actively monitoring the connection and disconnection of the new energy station, the operation mode of the new energy station can be accurately and quickly determined, solving the problem that the speed and accuracy of model simulation calculation cannot be taken into account when the AC fault external characteristics of the new energy station are present.

[0046] Optionally, performing reactive power disturbance on the new energy station to obtain a power disturbance response result includes: A ramp injection method is adopted to inject disturbance reactive power into the reference reactive power of the voltage control link of the flexible DC converter transformer according to a set slope, and the disturbance reactive power is injected for a first disturbance duration; Monitoring the actual value of reactive power corresponding to the flexible DC converter transformer; The amplitude achievement rate and the response achievement time are determined according to the reference reactive power, the actual reactive power value and the disturbance reactive power.

[0047] In practical applications, the disturbance reactive power ΔQ injected into the renewable energy station side is set through the flexible DC converter station controller. ref , using the ramp injection method and determining the duration T1 of the injected disturbance reactive power, that is, the first disturbance duration T1, the disturbance duration disturbance reactive power ΔQ ref The reference reactive power Q superimposed on the voltage control link ref superior.

[0048] Among them, the disturbance reactive power ΔQ ref The amplitude should avoid causing large power fluctuations and triggering new energy grid-off protection, and the sign should include positive and negative directions; the ramp injection method should avoid voltage flicker caused by step disturbances; the first disturbance duration should cover the AC system reverse response cycle.

[0049] Amplitude of disturbance reactive power: Set ΔQ ref To disturb the reactive capacity, ensure that the disturbance power fluctuation rate is less than the grid allowable value to avoid triggering the protection of renewable energy off-grid. Disturbance timing: adopt the ramp injection method, select the slope k, and avoid voltage flicker caused by step disturbance. Observation window: the duration T1 of the injected disturbance reactive power covers the reverse regulation response cycle of the AC system.

[0050] Further, monitor the disturbance reactive power ΔQ ref After injection, the actual reactive power value Q of the flexible DC converter transformer. And based on the reference reactive power Q ref , the actual reactive power value Q, and the disturbance reactive power ΔQ ref , calculate the amplitude achievement rate η Q and the response achievement duration T Q .

[0051] In this way, the accuracy and reliability of the reactive power disturbance can be ensured.

[0052] Optionally, determining the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual reactive power value, and the disturbance reactive power includes: Calculate the sum of the reference reactive power and the disturbance reactive power to obtain the superimposed reactive power; Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate; Obtain the first time when the disturbance reactive power is injected, and determine the second time when the actual reactive power value reaches the superimposed reactive power from the steady-state reactive power; Determine the time interval between the first time and the second time as the response achievement duration.

[0053] In practical applications, add the reference reactive power Q ref and the disturbance reactive power ΔQ ref to obtain the superimposed reactive power (total reactive power) Q ref +ΔQ ref . Further, calculate the ratio of the reference reactive power Q ref to the superimposed reactive power Q ref +ΔQ ref to obtain the amplitude achievement rate η Q ; and determine the time interval from the start of the reactive power disturbance to when the actual reactive power value Q reaches the added reactive power Q ref from the reference reactive power Q ref +ΔQ ref as the response achievement duration T Q .

[0054] Specifically, the time when the reactive power disturbance starts is the first time, that is, the time when the disturbance reactive power is injected; the time when the actual reactive power value Q reaches the added reactive power Q ref from the reference reactive power Q ref +ΔQ ref is the second time, and calculate the difference between the second time and the first time to obtain the response achievement duration.

[0055] In this way, the accuracy and reliability of the amplitude achievement rate and the response achievement duration can be ensured, and further, the accuracy of determining the operation mode based on the amplitude achievement rate and the response achievement duration can be provided.

[0056] Optionally, determining the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration includes: Judging whether the first condition corresponding to the pure DC operation mode is satisfied, where the first condition is that the amplitude achievement rate is greater than the achievement rate threshold and the response achievement duration is less than the achievement duration threshold; If not, determine that the operation mode of the new energy power station is the AC / DC hybrid operation mode; If so, perform a voltage disturbance on the new energy power station to obtain a voltage disturbance response result, where the voltage disturbance response result includes a voltage overshoot and a voltage steady-state error; determine the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error.

[0057] Specifically, the achievement rate threshold can be 95%. The duration threshold is the reference time considering the reverse regulation effect of the AC system and can be 1 second (s). The voltage steady-state error ε V represents the deviation between the steady-state voltage (reference voltage V ref ) and the total voltage; the voltage overshoot σ V refers to the ratio of the actual voltage value exceeding the total voltage.

[0058] In practical applications, judge whether the amplitude achievement rate η Q and the response achievement duration T Q meet the first condition corresponding to the pure DC operation mode (OM_DC), that is, the amplitude achievement rate η Q is greater than the achievement rate threshold and the response achievement duration T Q is less than the achievement duration threshold.

[0059] If not, it means that the operation mode of the new energy power station is the AC / DC hybrid operation mode (OM_AC / DC); if satisfied, it initially indicates that the operation mode of the new energy power station may be OM_DC, but further verification is still required, that is, a voltage disturbance test is performed.

[0060] Performing a voltage disturbance test means AC voltage regulation and observation: adjusting the AC voltage reference value of the grid-forming control, and recording the overshoot and steady-state error of the grid-connected AC voltage, that is, the voltage overshoot and the voltage steady-state error. Specifically, inject a disturbance voltage ΔV ref with a set amplitude into the new energy power station side, and record the voltage overshoot σ V and the voltage steady-state error ε V of the grid connection point.

[0061] Further, according to the response to the injected voltage perturbation, i.e., the voltage overshoot σ V and the voltage steady-state error ε V , and combining the voltage damping characteristics under OM_AC / DC and OM_DC, determine the operation mode of the new energy power station.

[0062] In this way, through the secondary verification of the injected voltage perturbation, the accuracy of the determined operation mode of the new energy power station can be guaranteed.

[0063] Optionally, the voltage perturbation is applied to the new energy power station to obtain a voltage perturbation response result, including: Inject a perturbation voltage on the reference voltage in the voltage control link of the flexible DC converter transformer and continue for the second perturbation duration; Monitor the actual voltage value corresponding to the flexible DC converter transformer; According to the reference voltage, the perturbation voltage, and the actual voltage value, determine the voltage overshoot and the voltage steady-state error.

[0064] Specifically, the perturbation voltage can be a step perturbation voltage.

[0065] In practical applications, on the reference voltage V ref , superimpose a perturbation voltage ΔV ref with a specific amplitude and a specific duration (the second perturbation duration T2), that is, the perturbation mode is to superimpose ΔV ref on the reference voltage V ref as a step perturbation for the second perturbation duration T2. Among them, the amplitude and duration of the perturbation voltage should avoid causing voltage deviation to lead to protection action and at the same time block the voltage regulation of the new energy power station.

[0066] Further, after tracking the injection of the perturbation voltage ΔV ref and when the system is stable, the actual voltage value V corresponding to the flexible DC converter transformer is obtained, and based on the actual voltage value V, the reference voltage V ref and the perturbation voltage ΔV ref , calculate the voltage overshoot σ V and the voltage steady-state error ε V .

[0067] In this way, the accuracy and reliability of the voltage perturbation can be guaranteed.

[0068] Optionally, the determining of the voltage overshoot and the voltage steady-state error according to the reference voltage, the perturbation voltage, and the actual voltage value includes: Calculate the sum of the reference voltage and the perturbation voltage to obtain a superimposed voltage; Determine the ratio of the actual voltage value exceeding the superimposed voltage as the voltage overshoot; Determine the deviation between the reference voltage and the superimposed voltage as the voltage steady-state error.

[0069] In practical applications, add the reference voltage V ref and the disturbance voltage ΔV ref to obtain the superimposed voltage (total voltage) V ref +ΔV ref . Further, calculate the first difference between the actual voltage value V and the superimposed voltage V ref +ΔV ref , then calculate the ratio of the first difference to the superimposed voltage V ref +ΔV ref to obtain the voltage overshoot σ V ; and take the second difference between the superimposed voltage V ref +ΔV ref and the reference voltage V ref , that is, the disturbance voltage ΔV re , f and the ratio of the superimposed voltage V ref +ΔV ref as the voltage steady-state error ε V .

[0070] In this way, the accuracy and reliability of the voltage overshoot and the voltage steady-state error can be guaranteed, and further, the accuracy of determining the operation mode based on the voltage overshoot and the voltage steady-state error can be provided.

[0071] Optionally, determining the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error includes: Judging whether the second condition corresponding to the pure DC operation mode is satisfied, where the second condition is that the voltage overshoot is less than the overshoot threshold and the voltage steady-state error is less than the steady-state error threshold; If not, determine the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, perform a frequency disturbance on the new energy power station to obtain a frequency disturbance response result, where the frequency disturbance response result includes a frequency oscillation rate and a frequency tracking accuracy; determine the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy.

[0072] Specifically, the overshoot threshold can be 1%. The steady-state error threshold can be 0.5%. The frequency tracking accuracy characterizes the root mean square error between the frequency measurement value and the total frequency.

[0073] In practical applications, judge whether the voltage overshoot σ V and the voltage steady-state error ε V meet the second condition corresponding to OM_DC, that is, the voltage overshoot σ VLess than the overshoot threshold and the voltage steady-state error ε V Less than the steady-state error threshold.

[0074] If not satisfied, it indicates that the operation mode of the new energy power station is OM_AC / DC; if satisfied, it preliminarily indicates that the operation mode of the new energy power station may be OM_DC, but further verification is still required, that is, setting a frequency perturbation test.

[0075] Set a frequency perturbation test, that is, perform a frequency perturbation on the new energy power station, observe and analyze the frequency dynamic behavior of the system, that is, the frequency oscillation rate A osc And the frequency tracking accuracy δ f , and then based on the frequency oscillation rate A osc And the frequency tracking accuracy δ f Finally determine the operation mode of the new energy power station.

[0076] In this way, through three verifications of injecting frequency perturbations, the accuracy of the determined operation mode of the new energy power station can be guaranteed.

[0077] Optionally, performing a frequency perturbation on the new energy power station to obtain a frequency perturbation response result includes: Injecting a perturbation frequency at the reference frequency of the frequency control link of the flexible DC converter transformer; Monitoring the frequency steady-state amplitude corresponding to the flexible DC converter transformer after the perturbation stabilizes; Determining the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the perturbation frequency.

[0078] Specifically, the perturbation frequency can be a step perturbation frequency. The frequency steady-state amplitude represents the stable amplitude of the frequency after the perturbation.

[0079] In practical applications, a perturbation frequency Δf with a specific amplitude and duration (the third perturbation duration T3) is superimposed on the reference frequency ω of the frequency control link ref . Among them, the amplitude and duration of the perturbation frequency should avoid triggering power oscillations and enable the virtual inertia control of the flexible DC.

[0080] Furthermore, after injecting and the system stabilizes while tracking the perturbation frequency Δf ref , the frequency steady-state amplitude f corresponding to the flexible DC converter transformer, and based on the frequency steady-state amplitude f, the reference frequency ω, and the perturbation frequency Δf ref , calculate the frequency oscillation rate A osc And the frequency tracking accuracy δ f .

[0081] In this way, the accuracy and reliability of performing the frequency perturbation can be guaranteed.

[0082] Optionally, determining the frequency oscillation rate and the frequency tracking accuracy according to the steady-state amplitude of the frequency, the reference frequency, and the disturbance frequency includes: Calculating the sum of the reference frequency and the disturbance frequency to obtain a superimposed frequency; Determining the root mean square error between the steady-state amplitude of the frequency and the superimposed frequency as the frequency tracking accuracy; Extracting the oscillation amplitude in a set frequency band through a fast Fourier transform algorithm to determine the frequency oscillation rate.

[0083] In practical applications, adding the reference frequency ω and the disturbance frequency Δf ref to obtain a superimposed frequency (total frequency) ω + Δf ref . Further, calculating the root mean square error between the steady-state amplitude of the frequency f and the superimposed frequency ω + Δf ref to obtain the frequency tracking accuracy δ f ; and extracting the oscillation amplitude in a set frequency band through a fast Fourier transform (FFT) algorithm to obtain the frequency oscillation rate A osc .

[0084] In this way, the accuracy and reliability of the frequency oscillation rate and the frequency tracking accuracy can be ensured, and further, the accuracy of determining the operation mode based on the frequency oscillation rate and the frequency tracking accuracy can be provided.

[0085] Optionally, determining the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy includes: Judging whether the third condition corresponding to the pure DC operation mode is satisfied, where the third condition is that the frequency oscillation rate is less than the oscillation rate threshold and the frequency tracking accuracy is less than the accuracy threshold; If not, determining the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, determining the operation mode of the new energy power station as the pure DC operation mode.

[0086] In practical applications, if the frequency oscillation rate A osc and the frequency tracking accuracy δ f meet the set thresholds and there is no power oscillation phenomenon, it is considered that the new energy power station operates as OM_DC: Judging whether the frequency oscillation rate A osc and the frequency tracking accuracy δ f meet the third condition corresponding to OM_DC, that is, the frequency oscillation rate A osc is less than the oscillation rate threshold and the frequency tracking accuracy δ f is less than the accuracy threshold.

[0087] If not satisfied, it indicates that the operation mode of the new energy power station is OM_AC / DC; if satisfied, it indicates that the operation mode of the new energy power station may be OM_DC.

[0088] In this way, through triple verification, the accuracy of the determined operation mode of the new energy power station is guaranteed.

[0089] Optionally, before performing reactive power perturbation on the new energy power station to obtain the power perturbation response result, it further includes: Obtaining grid dispatching information, where the grid dispatching information includes at least one of a new energy operation mode instruction, an AC switch status, and a protection action behavior information; Based on the grid dispatching information, determining the operation mode of the new energy power station; If the determination fails, then execute the steps before performing reactive power perturbation on the new energy power station to obtain the power perturbation response result.

[0090] In practical applications, the operation mode of the new energy power station can be determined by identifying at least one of the new energy operation mode instruction, AC switch status, and protection action behavior information issued by the grid dispatching. In this way, the efficiency of determining the operation mode of the new energy power station can be improved.

[0091] Exemplarily, for the scenario of a newly constructed new energy power station connected to the grid through AC-DC hybrid transmission, the new energy operation mode instruction and / or the protection action behavior information contain the identifier of the operation mode corresponding to the new energy power station. Therefore, the new energy operation mode instruction and / or the protection action behavior information can be obtained, the identifier of the operation mode can be extracted from the new energy operation mode instruction and / or the protection action behavior information, and then the operation mode of the new energy power station can be determined based on this identifier.

[0092] Exemplarily, for the scenario of a new energy power station connected to the grid through AC-DC hybrid transmission, as Figure 1 shown, if the circuit breaker K1 is disconnected (AC switch status), then the operation mode of the new energy power station is OM_DC; if the circuit breaker K1 is closed (AC switch status), then the operation mode of the new energy power station is OM_AC / DC.

[0093] If the operation mode of the new energy power station cannot be determined based on the grid dispatching information, then reactive power perturbation can be performed on the new energy power station to determine the operation mode of the new energy power station.

[0094] Next, a further description of the method for determining the operation mode of the new energy power station provided by the present invention will be given in conjunction with Figures 3 - 9 See

[0095] See Figure 3 , Figure 3 is a schematic diagram of injecting perturbation into a flexible DC converter transformer provided by the present invention: where, Pe and P ref are respectively the output active power and the active reference value of the flexible DC VSC; KDp is the damping coefficient; J is the inertia coefficient; s is the Laplace factor, ω0 is the angular frequency (i.e., the disturbance frequency Δf ref ), θ is the angle, e is the electromotive force; u o D is the port voltage of the flexible DC VSC (i.e., the disturbance voltage ΔV ref ); Q e and Q ref are respectively the output reactive power and the reactive reference value (base reactive power) of the flexible DC VSC; K q s is the integral factor; Dq is the superimposed voltage of u o D and the base voltage V ref ; abc represents the three-phase coordinate system, i.e., the abc three-phase coordinate system, and dq represents the coordinate system composed of the quadrature axis and the direct axis. After being processed by the voltage regulation link and the frequency regulation link, it enters the current inner loop control link, and then is processed by the voltage-controlled VSG, i.e., processed by PWM (Pulse Width Modulation) and triodes.

[0096] Among them, the disturbance reactive power ΔQ ref is superimposed on the base reactive power Q ref in the voltage regulation control link (voltage regulation link), and the disturbance voltage ΔV ref is superimposed on the base voltage V ref in the voltage regulation control link (voltage regulation link), and the disturbance frequency Δf ref is superimposed on the base frequency ω in the frequency regulation control link (frequency regulation link).

[0097] First, obtain the operation mode of the new energy power station through the power grid dispatching information.

[0098] If the operation mode of the new energy power station cannot be directly obtained through the power grid dispatching information, then enter the "three-step disturbance injection - multi-dimensional response analysis" active detection process, where the three-step disturbance injection - multi-dimensional response analysis means respectively performing reactive power disturbance, voltage disturbance and frequency disturbance, and analyzing the response results of each disturbance.

[0099] Then, perform the VSC additional reactive power disturbance detection process, that is, perform reactive power disturbance.

[0100] On the base reactive power Q ref in the VSC voltage control link, superimpose the disturbance reactive power ΔQ ref =±5%Q n , where Q n is the rated reactive power. Adopt the ramp injection method, and select the slope k = 0.5%Q n / millisecond (ms), the disturbance duration (the first disturbance duration) T1 = 2 s.

[0101] Set η Q > 95% and T Q < 1 s, that is, the achievement rate threshold is 95% and the achievement duration threshold is 1 s. The operation mode of the new energy power station is OM_DC, otherwise OM_AC / DC.

[0102] See Figure 4 and Figure 5 , Figure 4 is the reactive power response waveform diagram of the connection point of the new energy power station provided by the present invention under the pure DC operation mode, Figure 5 is the reactive power response waveform diagram of the connection point of the new energy power station provided by the present invention under the AC-DC hybrid operation mode: injecting the disturbance reactive power ΔQ ref After that, η Q = 100%, T Q = 100 ms. Therefore, it is preliminarily judged that the new energy power station operates as OM_DC. After injecting the disturbance reactive power ΔQ ref After that, the volatility of the reactive power is less than the grid allowable value ≤ 3%, and the new energy disconnection protection and voltage flicker are not triggered. Figure 4 and Figure 5 In, the dotted line represents the response waveform corresponding to Q ref , the solid line represents the response waveform corresponding to Q, Q = ΔQ ref + Q ref .

[0103] Next, perform the VSC additional voltage disturbance detection process, that is, perform voltage disturbance.

[0104] On the reference voltage V ref of the VSC voltage control link, superimpose the disturbance voltage ΔV ref = ± 5% Vn, where V n is the rated voltage, and the disturbance duration (the second disturbance duration) T2 = 5 s.

[0105] Set that due to the reverse regulation effect during hybrid transmission (the new energy power station operates as OM_AC / DC), σ V > 3%, and when pure DC transmission (the new energy power station operates as OM_DC), σ V < 1%; set that due to the integral link of the grid-forming control to eliminate the steady-state error, when pure DC transmission, ε V < 0.5%, and due to the difference in AC line impedance during hybrid transmission, ε V > 1%. That is, the overshoot threshold is 1% and the steady-state error threshold is 0.5%.

[0106] See Figure 6 and Figure 7 ,Figure 6 It is the voltage response waveform diagram of the grid connection point of the new energy power station provided by the present invention under the pure DC operation mode. Figure 7 It is the voltage response waveform diagram of the grid connection point of the new energy power station provided by the present invention under the AC-DC hybrid operation mode: injecting a disturbance voltage ΔV ref After that, calculate the voltage overshoot σ V < 1% and the voltage steady-state error ε V < 0.2%. The disturbance amplitude is limited by the power quality requirements (voltage deviation ≤ ±5%). It can be seen that the voltage overshoot σ V < 1% and the voltage steady-state error ε V are less than the reference values considering the voltage reverse regulation effect of the AC system, then it is preliminarily judged that the operation mode of the new energy power station is OM_DC. Figure 6 and Figure 7 In, the dotted line represents the response waveform corresponding to V ref The solid line represents the response waveform corresponding to V, V = ΔV ref + V ref .

[0107] Finally, perform VSC frequency disturbance detection, that is, perform frequency disturbance.

[0108] If it is judged that the operation mode of the new energy power station is OM_DC based on both the power disturbance response result and the voltage disturbance response result, then set the frequency perturbation test.

[0109] On the reference frequency ω (f ref ) of the VSC frequency control link, superimpose a step disturbance frequency Δf with a specific amplitude and duration (the third disturbance duration) ref = ±0.05 Hertz (Hz); the amplitude and duration of Δf ref should avoid triggering power oscillation and enable the virtual inertia control of the flexible DC. Enable the virtual inertia control of the flexible DC during the disturbance, and the inertia time constant H = 3s.

[0110] Extract the oscillation amplitude in the 0.01 - 2 Hz frequency band through FFT to obtain the frequency oscillation rate A osc . Set A osc > 2% when mixed sending out (the new energy power station operates in OM_AC / DC), and A osc < 0.5% when pure DC sending out (the new energy power station operates in OM_DC). Set δ f > 0.02 Hz when mixed sending out, and δ f < 0.005 per unit value (Pu) when pure DC sending out. That is, the oscillation rate threshold is 0.5%, and the accuracy threshold is 0.005 Pu.

[0111] See Figure 8 and Figure 9 ,Figure 8 It is the waveform diagram of the frequency response and power response of the grid connection point of the new energy power station provided by the present invention under the pure DC operation mode. Figure 9 It is the waveform diagram of the frequency response and power response of the grid connection point of the new energy power station provided by the present invention under the AC-DC hybrid operation mode: frequency oscillation rate A osc <0.3%, frequency tracking accuracy δ f <0.003Pu, that is, when the frequency oscillation rate and frequency tracking accuracy meet the set threshold and there is no power oscillation phenomenon, the operation mode of the new energy power station is considered as OM_DC. Figure 8 and Figure 9 In, the upper figures are all waveform diagrams of frequency response, the lower figures are all waveform diagrams of power response, and the dotted lines in the upper figures represent the response waveforms corresponding to f ref The corresponding response waveforms, the solid lines represent the response waveforms corresponding to f, f = Δf ref + f ref .

[0112] In the embodiment of the present invention, hierarchical disturbance injection is implemented through a flexible DC control system (flexible DC converter transformer): firstly, disturbance reactive power is injected into the new energy power station side, and the amplitude achievement rate and response achievement duration of the grid connection point are monitored in real time; a step disturbance voltage is applied synchronously, and the voltage overshoot and voltage steady-state error are extracted; a primary judgment is made based on the voltage damping ratio differences (achievement rate threshold, achievement duration threshold, overshoot threshold, and steady-state error threshold) between the pure DC operation mode and the AC-DC hybrid operation mode. If it is determined to be the pure DC operation mode, the disturbance frequency is injected, and re-verification is achieved through the frequency oscillation rate and frequency tracking accuracy. On the premise of ensuring the steady operation of the system, the operation mode of the new energy power station is actively detected through non-intrusive disturbance, significantly improving the control stability and oscillation suppression ability of the flexible DC converter transformer.

[0113] Next, the device for determining the operation mode of the new energy power station provided by the present invention will be described. The device for determining the operation mode of the new energy power station described below can be mutually referred to the method for determining the operation mode of the new energy power station described above.

[0114] See Figure 10 , Figure 10 It is the structural schematic diagram of the device for determining the operation mode of the new energy power station provided by the present invention. As Figure 10 shown, the device includes the following: The disturbance module 1001 is configured to perform reactive power disturbance on the new energy power station to obtain a power disturbance response result, and the power disturbance response result includes an amplitude achievement rate and a response achievement duration; The determination module 1002 is configured to determine the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

[0115] Optionally, the perturbation module 1001 is specifically configured to: Adopt a ramp injection method to inject perturbation reactive power at a set slope on the reference reactive power in the voltage control link of the flexible DC converter transformer, and continue for the first perturbation duration; Monitor the actual value of the reactive power corresponding to the flexible DC converter transformer; Determine the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual value of the reactive power, and the perturbation reactive power.

[0116] Optionally, the perturbation module 1001 is specifically configured to: Calculate the sum of the reference reactive power and the perturbation reactive power to obtain the superimposed reactive power; Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate; Obtain the first time when the perturbation reactive power is injected, and determine the second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power; Determine the time interval between the first time and the second time as the response achievement duration.

[0117] Optionally, the determination module 1002 is specifically configured to: Judge whether the first condition corresponding to the pure DC operation mode is satisfied, where the first condition is that the amplitude achievement rate is greater than the achievement rate threshold and the response achievement duration is less than the achievement duration threshold; If not, determine that the operation mode of the new energy power station is the AC-DC hybrid operation mode; If so, perform voltage perturbation on the new energy power station to obtain a voltage perturbation response result, where the voltage perturbation response result includes a voltage overshoot and a voltage steady-state error; determine the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error.

[0118] Optionally, the determination module 1002 is specifically configured to: Inject a perturbation voltage on the reference voltage in the voltage control link of the flexible DC converter transformer, and continue for the second perturbation duration; Monitor the actual value of the voltage corresponding to the flexible DC converter transformer; Determine the voltage overshoot and the voltage steady-state error according to the reference voltage, the perturbation voltage, and the actual value of the voltage.

[0119] Optionally, the determination module 1002 is specifically configured to: Calculate the sum of the reference voltage and the perturbation voltage to obtain the superimposed voltage; Determine the ratio of the actual voltage value exceeding the superimposed voltage as the voltage overshoot; Determine the deviation between the reference voltage and the superimposed voltage as the voltage steady-state error.

[0120] Optionally, the determination module 1002 is specifically configured to: Judge whether the second condition corresponding to the pure DC operation mode is satisfied, where the second condition is that the voltage overshoot is less than the overshoot threshold and the voltage steady-state error is less than the steady-state error threshold; If not, determine the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, perform a frequency perturbation on the new energy power station to obtain a frequency perturbation response result, where the frequency perturbation response result includes a frequency oscillation rate and a frequency tracking accuracy; determine the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy.

[0121] Optionally, the determination module 1002 is specifically configured to: Inject a perturbation frequency at the reference frequency of the flexible DC converter transformer frequency control link; Monitor the frequency steady-state amplitude corresponding to the flexible DC converter transformer after the perturbation stabilizes; Determine the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the perturbation frequency.

[0122] Optionally, the determination module 1002 is specifically configured to: Calculate the sum of the reference frequency and the perturbation frequency to obtain a superimposed frequency; Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy; Determine the deviation between the reference voltage and the superimposed voltage as the voltage steady-state error.

[0123] Extract the oscillation amplitude of the set frequency band through the fast Fourier transform algorithm to determine the frequency oscillation rate.

[0124] Optionally, the determination module 1002 is specifically configured to: Judge whether the third condition corresponding to the pure DC operation mode is satisfied, where the third condition is that the frequency oscillation rate is less than the oscillation rate threshold and the frequency tracking accuracy is less than the accuracy threshold; If not, determine the operation mode of the new energy power station as the AC-DC hybrid operation mode; If so, determine the operation mode of the new energy power station as the pure DC operation mode.

[0125] Optionally, the device further includes an acquisition module configured to: acquire grid dispatching information, where the grid dispatching information includes at least one of a new energy operation mode instruction, an AC switch state, and a protection action behavior information; determine the operation mode of the new energy power station based on the grid dispatching information; if the determination fails, execute the steps before performing the reactive power disturbance on the new energy power station to obtain a power disturbance response result.

[0126] Figure 11 is a schematic structural diagram of an electronic device provided by the present invention. As Figure 11 shown, the electronic device may include: a processor 1110, a communication interface 1120, a memory 1130, and a communication bus 1140. Among them, the processor 1110, the communication interface 1120, and the memory 1130 complete mutual communication through the communication bus 1140. The processor 1110 may call logic instructions in the memory 1130 to execute the method for determining the operation mode of the new energy power station.

[0127] In addition, when the logic instructions in the above-mentioned memory 1130 are implemented in the form of a software functional unit and sold or used as an independent product, they may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc that can store program codes.

[0128] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method for determining the operation mode of the new energy power station provided by the above-mentioned various methods.

[0129] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is configured to execute the method for determining the operation mode of a new energy power station provided by each of the above methods.

[0130] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

[0131] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, these modifications or replacements 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 method for determining the operation mode of a new energy power station, characterized in that Including: Performing reactive power disturbance on a new energy power station to obtain a power disturbance response result, where the power disturbance response result includes an amplitude achievement rate and a response achievement duration; Determining the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

2. The method for determining the operation mode of the new energy power station according to claim 1, characterized in that The performing reactive power disturbance on the new energy power station to obtain a power disturbance response result includes: Adopting a ramp injection method to inject disturbance reactive power at a set slope on the reference reactive power in the voltage control link of the flexible DC converter transformer and lasting for a first disturbance duration; Monitoring the actual reactive power value corresponding to the flexible DC converter transformer; Determining the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual reactive power value, and the disturbance reactive power.

3. The method for determining the operation mode of a new energy power station according to claim 2, wherein The determining the amplitude achievement rate and the response achievement duration according to the reference reactive power, the actual reactive power value, and the disturbance reactive power includes: Calculating the sum of the reference reactive power and the disturbance reactive power to obtain a superimposed reactive power; Determining the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate; Obtaining the first time when the disturbance reactive power is injected and determining the second time when the actual reactive power value reaches the superimposed reactive power from the steady-state reactive power; Determining the time interval between the first time and the second time as the response achievement duration.

4. The method for determining the operation mode of the new energy power station according to claim 1, characterized in that The determining the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration includes: Judging whether the first condition corresponding to the pure DC operation mode is satisfied, where the first condition is that the amplitude achievement rate is greater than an achievement rate threshold and the response achievement duration is less than a response duration threshold; If not, determining the operation mode of the new energy power station as an AC-DC hybrid operation mode; If so, performing voltage disturbance on the new energy power station to obtain a voltage disturbance response result, where the voltage disturbance response result includes a voltage overshoot and a voltage steady-state error; determining the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error.

5. The method for determining the operation mode of the new energy power station according to claim 4, wherein The performing voltage disturbance on the new energy power station to obtain a voltage disturbance response result includes: Injecting a disturbance voltage on the reference voltage in the voltage control link of the flexible DC converter transformer and lasting for a second disturbance duration; Monitoring the actual voltage value corresponding to the flexible DC converter transformer; Determining the voltage overshoot and the voltage steady-state error according to the reference voltage, the disturbance voltage, and the actual voltage value; The determining the voltage overshoot and the voltage steady-state error according to the reference voltage, the disturbance voltage, and the actual voltage value includes: Calculating the sum of the reference voltage and the disturbance voltage to obtain a superimposed voltage; Determining the ratio of the actual voltage value exceeding the superimposed voltage as the voltage overshoot; Determining the deviation between the reference voltage and the superimposed voltage as the voltage steady-state error.

6. The method for determining the operation mode of the new energy power station according to claim 4, wherein The determining the operation mode of the new energy power station according to the voltage overshoot and the voltage steady-state error includes: Determine whether the second condition corresponding to the pure DC operation mode is satisfied, where the second condition is that the voltage overshoot is less than the overshoot threshold and the voltage steady-state error is less than the steady-state error threshold; If not, determine that the operation mode of the new energy power station is the AC-DC hybrid operation mode; If so, perform a frequency disturbance on the new energy power station to obtain a frequency disturbance response result, where the frequency disturbance response result includes a frequency oscillation rate and a frequency tracking accuracy; determine the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy.

7. The method for determining the operation mode of the new energy power station according to claim 6, wherein The performing a frequency disturbance on the new energy power station to obtain a frequency disturbance response result includes: Inject a disturbance frequency at the reference frequency in the frequency control link of the flexible DC converter transformer; Monitor the frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance stabilizes; Determine the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the disturbance frequency; The determining the frequency oscillation rate and the frequency tracking accuracy according to the frequency steady-state amplitude, the reference frequency, and the disturbance frequency includes: Calculate the sum of the reference frequency and the disturbance frequency to obtain a superimposed frequency; Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy; Extract the oscillation amplitude in a set frequency band through the fast Fourier transform algorithm to determine the frequency oscillation rate.

8. The method for determining the operation mode of a new energy power station according to claim 6, characterized in that The determining the operation mode of the new energy power station according to the frequency oscillation rate and the frequency tracking accuracy includes: Determine whether the third condition corresponding to the pure DC operation mode is satisfied, where the third condition is that the frequency oscillation rate is less than the oscillation rate threshold and the frequency tracking accuracy is less than the accuracy threshold; If not, determine that the operation mode of the new energy power station is the AC-DC hybrid operation mode; If so, determine that the operation mode of the new energy power station is the pure DC operation mode.

9. The method for determining the operation mode of a new energy power station according to any one of claims 1-8, characterized in that Before performing a reactive power disturbance on the new energy power station to obtain a power disturbance response result, it further includes: Obtain grid dispatching information, where the grid dispatching information includes at least one of a new energy operation mode instruction, an AC switch state, and protection action behavior information; Based on the grid dispatching information, determine the operation mode of the new energy power station; If the determination fails, execute the steps before performing a reactive power disturbance on the new energy power station to obtain a power disturbance response result.

10. A device for determining the operation mode of a new energy power station, characterized in that, It includes: A disturbance module configured to perform a reactive power disturbance on the new energy power station to obtain a power disturbance response result, where the power disturbance response result includes an amplitude achievement rate and a response achievement duration; A determination module configured to determine the operation mode of the new energy power station according to the amplitude achievement rate and the response achievement duration.

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