Method and device for determining operation mode of new energy station

Abstract

The present invention provides a method and device for determining the operating mode of a new energy station, relating to the technical field of monitoring new energy power systems. The method comprises: performing a 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 determining the operating mode of the new energy station based on the amplitude achievement rate and the response achievement time. The present invention can accurately and quickly determine the operating mode of the new energy station.

Description

Technical Field

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

[0002] The installed share of renewable energy sources such as wind power and photovoltaics continues to rise. Voltage Source Converter-based High Voltage Direct Current Transmission (VSC-HVDC), due to its flexible reactive power regulation capabilities and grid-connected characteristics, has become a core technology for the large-scale transmission of renewable energy.

[0003] According to an International Energy Agency report, 45% of renewable energy stations worldwide already utilize a combined "flexible DC + AC" transmission solution. While this hybrid system improves transmission capacity and flexibility, it also presents challenges in identifying its operating mode. The transmission path (pure DC, AC / DC parallel) and on-grid and off-grid status of the renewable energy station directly impact the system's stability control strategy. Therefore, an effective solution is urgently needed to address these issues. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a method and device for determining the operating mode of a new energy station.

[0005] The present invention provides a method for determining an operating mode of a new energy station, comprising:

[0006] Performing 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;

[0007] An operation mode of the new energy station is determined according to the amplitude achievement rate and the response achievement time.

[0008] According to a method for determining an operating mode of a new energy station provided by the present invention, performing reactive power disturbance on the new energy station to obtain a power disturbance response result includes:

[0009] Adopting the ramp injection method, the disturbance reactive power is injected into the reference reactive power of the voltage control link of the flexible DC converter transformer according to the set slope and lasts for the first disturbance duration;

[0010] Monitoring the actual value of reactive power corresponding to the flexible DC converter transformer;

[0011] 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.

[0012] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the amplitude achievement rate and the response achievement time based on the reference reactive power, the actual reactive power value, and the disturbance reactive power includes:

[0013] Calculating the sum of the reference reactive power and the disturbance reactive power to obtain superimposed reactive power;

[0014] Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate;

[0015] Obtaining a first time of injecting the disturbance reactive power, and determining a second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power;

[0016] The time interval between the first time and the second time is determined as the response achievement duration.

[0017] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the operating mode of the new energy station according to the amplitude achievement rate and the response achievement time includes:

[0018] Determining whether a first condition corresponding to a pure DC operation mode is met, the first condition being that the amplitude achievement rate is greater than an achievement rate threshold, and the response achievement time is less than an achievement time threshold;

[0019] If not, determining that the operation mode of the new energy station is an AC / DC hybrid operation mode;

[0020] If so, a voltage disturbance is performed on the new energy station to obtain a voltage disturbance response result, which includes a voltage overshoot and a voltage steady-state error; and an operating mode of the new energy station is determined based on the voltage overshoot and the voltage steady-state error.

[0021] According to a method for determining an operating mode of a new energy station provided by the present invention, performing a voltage disturbance on the new energy station to obtain a voltage disturbance response result includes:

[0022] Injecting a disturbance voltage into the reference voltage of the voltage control link of the flexible DC converter transformer for a second disturbance duration;

[0023] Monitoring the actual voltage value corresponding to the flexible DC converter transformer;

[0024] The voltage overshoot and the voltage steady-state error are determined according to the reference voltage, the disturbance voltage, and the actual voltage value.

[0025] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the voltage overshoot and the voltage steady-state error based on the reference voltage, the disturbance voltage, and the actual voltage value includes:

[0026] Calculating the sum of the reference voltage and the disturbance voltage to obtain a superimposed voltage;

[0027] The ratio by which the actual voltage value exceeds the superimposed voltage is determined as the voltage overshoot;

[0028] The deviation between the reference voltage and the superimposed voltage is determined as a voltage steady-state error.

[0029] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the operating mode of the new energy station according to the voltage overshoot and the voltage steady-state error includes:

[0030] determining whether a second condition corresponding to the pure DC operation mode is satisfied, the second condition being that the voltage overshoot is less than an overshoot threshold and the voltage steady-state error is less than a steady-state error threshold;

[0031] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0032] If so, the frequency disturbance is performed on the new energy station to obtain a frequency disturbance response result, which includes a frequency oscillation rate and a frequency tracking accuracy; and the operation mode of the new energy station is determined according to the frequency oscillation rate and the frequency tracking accuracy.

[0033] According to a method for determining an operating mode of a new energy station provided by the present invention, performing frequency disturbance on the new energy station to obtain a frequency disturbance response result includes:

[0034] Injecting a disturbance frequency into the reference frequency of the frequency control link of the flexible DC converter transformer;

[0035] monitoring a frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance is stabilized;

[0036] The frequency oscillation rate and the frequency tracking accuracy are determined according to the frequency steady-state amplitude, the reference frequency and the disturbance frequency.

[0037] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the frequency oscillation rate and the frequency tracking accuracy based on the frequency steady-state amplitude, the reference frequency, and the disturbance frequency includes:

[0038] Calculating the sum of the reference frequency and the disturbance frequency to obtain a superposition frequency;

[0039] Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy;

[0040] The oscillation amplitude of the set frequency band is extracted by a fast Fourier transform algorithm to determine the frequency oscillation rate.

[0041] According to a method for determining an operating mode of a new energy station provided by the present invention, determining the operating mode of the new energy station according to the frequency oscillation rate and the frequency tracking accuracy includes:

[0042] determining whether a third condition corresponding to the pure DC operation mode is satisfied, wherein the third condition is that the frequency oscillation rate is less than an oscillation rate threshold, and the frequency tracking accuracy is less than an accuracy threshold;

[0043] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0044] If so, it is determined that the operation mode of the new energy station is the pure DC operation mode.

[0045] According to a method for determining an operating mode of a new energy station provided by the present invention, before performing reactive power disturbance on the new energy station and obtaining a power disturbance response result, the method further includes:

[0046] Acquiring grid dispatch information, where the grid dispatch information includes at least one of a new energy operation mode instruction, an AC switch status, and protection action behavior information;

[0047] Determining an operating mode of the new energy station based on the grid dispatch information;

[0048] If it is determined to be a failure, the steps before performing reactive power disturbance on the new energy station and obtaining the power disturbance response result are executed.

[0049] The present invention also provides a device for determining an operating mode of a new energy station, comprising:

[0050] A disturbance module is configured to perform reactive power disturbance on the new energy station and obtain a power disturbance response result, wherein the power disturbance response result includes an amplitude achievement rate and a response achievement time;

[0051] The determination module is configured to determine the operation mode of the new energy station according to the amplitude achievement rate and the response achievement time.

[0052] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for determining the operating mode of a new energy station as described above is implemented.

[0053] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for determining the operating mode of a new energy station as described in any one of the above is implemented.

[0054] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method for determining the operating mode of a new energy station as described above.

[0055] The present invention provides a method and device for determining the operating mode of a new energy station. By subjecting the new energy station to a reactive power disturbance, a power disturbance response result is obtained, including an amplitude achievement rate and a response achievement duration. The operating mode of the new energy station is determined based on the amplitude achievement rate and the response achievement duration. Active on-grid and off-grid monitoring of the new energy station allows for accurate and rapid determination of its operating mode, resolving the issue of balancing model simulation speed and accuracy when considering AC fault characteristics of the new energy station. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to 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 any creative work.

[0057] Figure 1 This is a schematic diagram of the power grid topology for the AC / DC combined transmission scenario of the new energy station provided by the present invention.

[0058] 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.

[0059] Figure 3 It is a schematic diagram of the disturbance injection into the flexible DC converter transformer provided by the present invention.

[0060] Figure 4 This is a reactive power response waveform diagram of the new energy station grid connection point provided by the present invention under pure DC operation mode.

[0061] Figure 5 This is a reactive power response waveform diagram of the new energy station grid connection point provided by the present invention under the AC / DC hybrid operation mode.

[0062] Figure 6 This is a voltage response waveform diagram of the new energy station grid connection point provided by the present invention under pure DC operation mode.

[0063] Figure 7 This is a voltage response waveform diagram of the new energy station grid connection point provided by the present invention under AC / DC hybrid operation mode.

[0064] 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.

[0065] Figure 9 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 the AC / DC hybrid operation mode.

[0066] Figure 10 It is a structural diagram of the device for determining the operating mode of a new energy station provided by the present invention.

[0067] Figure 11 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0068] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0069] The following combination Figures 1-11 The present invention describes a method and device for determining the operation mode of a new energy station.

[0070] First, the relevant contents of the present invention are briefly described.

[0071] Existing research shows that the dynamic characteristics of hybrid AC / DC systems exhibit significant differences. In pure DC transmission scenarios, the flexible DC converter station serves as the sole voltage source, resulting in fast reactive power regulation and minimal overshoot. In combined AC / DC transmission scenarios, the parallel connection of AC lines and flexible DC increases system inertia, leading to delayed reactive power response and significant oscillations. In isolated, off-grid scenarios, the system's frequency self-regulation capability is weak, and even small frequency disturbances can trigger sustained frequency deviations. Flexible DC systems with grid-forming capabilities can autonomously establish voltage and frequency without the support of synchronous power sources, making them suitable for weak grids or isolated island scenarios. The limitations of AC lines, affected by cable capacitance, lead to excess reactive power over long distances and poor fault ride-through capability. Hybrid transmission is essential, with flexible DC providing baseload transmission and AC lines serving as backup or local power regulation channels. However, the dynamic coupling between the two leads to significant transmission path unobservability. The reactive power reverse regulation of the AC lines can offset the reactive power disturbance response of the flexible DC system, obscuring information about the actual transmission path. However, existing technologies fail to effectively integrate multi-dimensional dynamic characteristics such as reactive power, voltage, and frequency, resulting in judgments based on a single basis or difficulty in obtaining information on the operating mode.

[0072] Flexible direct current has the ability to build a network, 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 new energy stations.

[0073] The method for determining the operating mode of a new energy station provided in an embodiment of the present invention is applied to the following scenario in which a new energy station transmits power via a combined AC and DC power supply.

[0074] See also Figure 1 , Figure 1 This is a schematic diagram of the grid topology for a combined AC / DC transmission scenario at a new energy station, as provided by the present invention. The new energy station includes multiple photovoltaic (PV) and wind turbine units, along with corresponding AC transformers for each unit (PV and wind). Power is transmitted from the station via a flexible DC converter transformer (VSC) and an AC system (Grid_1). The PV and wind turbine units are boosted to 330 kV via two-stage AC transformers (a primary and a secondary). The voltage is then connected to the ±400 kilovolt (kV) VSC via circuit breakers K1 and K2, electrical measurement points, and a transformer. The AC system Grid_1 is connected to the new energy station via circuit breaker K0 and a transformer. The rated capacity of the new energy station is 200 megawatts (MW), and the rated capacity of the VSC is 500 MW.

[0075] Figure 2 This is a flow chart of the method for determining the operation mode of a new energy station provided by the present invention, such as Figure 2 As shown, the method includes the following:

[0076] Step 201: 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.

[0077] Specifically, the amplitude achievement rate refers to the steady-state reactive power (reference reactive power Q ref ) to the total reactive power. Response time refers to the time it takes from the injection of a reactive power disturbance to the stabilization of the reactive power.

[0078] In practical applications, reactive power disturbance injection can be performed on the new energy station: a disturbance reactive power ΔQ of set amplitude is injected into the new energy station side. ref , observe the actual value of reactive power at the grid connection point of the flexible DC converter transformer, and calculate the amplitude achievement rate η Q and response time T Q .

[0079] Step 202: Determine the operation mode of the new energy station according to the amplitude achievement rate and the response achievement time.

[0080] In practical applications, when injecting reactive power disturbance into new energy stations, the amplitude achievement rate η is obtained. Q and response time T Q After that, the response analysis is performed, that is, the amplitude achievement rate η Q and response time T Q Conduct analysis to obtain the operation mode of new energy stations.

[0081] The method for determining the operating mode of a new energy station provided by the present invention performs a reactive power disturbance on the new energy station to obtain a power disturbance response result, which includes an amplitude achievement rate and a response achievement time. The operating mode of the new energy station is determined based on the amplitude achievement rate and the response achievement time. Active on-grid and off-grid monitoring of the new energy station allows for accurate and rapid determination of the station's operating mode, resolving the issue of balancing model simulation speed and accuracy when considering AC fault characteristics of the new energy station.

[0082] Optionally, performing reactive power disturbance on the new energy station to obtain a power disturbance response result includes:

[0083] Adopting the ramp injection method, the disturbance reactive power is injected into the reference reactive power of the voltage control link of the flexible DC converter transformer according to the set slope and lasts for the first disturbance duration;

[0084] Monitoring the actual value of reactive power corresponding to the flexible DC converter transformer;

[0085] 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.

[0086] 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 , adopt the ramp injection method and determine the duration T1 of the injected disturbance reactive power, that is, the first disturbance duration T1, and convert the disturbance duration to disturbance reactive power ΔQ ref The reference reactive power Q superimposed on the voltage control link ref superior.

[0087] Among them, the disturbance reactive power ΔQ ref Its amplitude should avoid causing large power fluctuations and triggering new energy grid disconnection protection, and the sign should include positive and negative bidirectionality; the ramp injection method should avoid voltage flicker caused by step disturbances; the first disturbance duration should cover the AC system reverse regulation response cycle.

[0088] The amplitude of the disturbance reactive power: set ΔQ ref To disturb reactive power capacity, ensure that the disturbance power fluctuation rate is less than the grid's allowable value to avoid triggering renewable energy disconnection protection. Disturbance timing: Use a ramp injection method with a selected slope k to avoid voltage flicker caused by step disturbances. Observation window: The duration T1 of the injected disturbance reactive power should cover the AC system's reverse regulation response period.

[0089] Furthermore, the disturbance reactive power ΔQ is monitored ref After injection, the actual value of reactive power corresponding to the flexible DC converter transformer is Q. And based on the reference reactive power Q ref , reactive power actual value Q. and disturbance reactive power ΔQ ref , calculate the amplitude achievement rate η Q and response time T Q .

[0090] In this way, the accuracy and reliability of reactive power disturbance can be guaranteed.

[0091] Optionally, determining the amplitude achievement rate and the response achievement time according to the reference reactive power, the actual reactive power value, and the disturbance reactive power includes:

[0092] Calculating the sum of the reference reactive power and the disturbance reactive power to obtain superimposed reactive power;

[0093] Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate;

[0094] Obtaining a first time of injecting the disturbance reactive power, and determining a second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power;

[0095] The time interval between the first time and the second time is determined as the response achievement duration.

[0096] In practical applications, the reference reactive power Q ref and disturbance reactive power ΔQ ref Add together to get the superimposed reactive power (total reactive power) Q ref +ΔQ ref . Further, calculate the reference reactive power Q ref and superimposed reactive power Q ref +ΔQ ref The ratio of the amplitude to achieve the rate η Q ; and the reactive power disturbance starts from the actual value of reactive power Q from the reference reactive power Q ref Reaching reactive power Q ref +ΔQ ref The time interval is determined as the response reaching time T Q .

[0097] 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 actual value of reactive power Q changes from the reference reactive power Q ref Reaching reactive power Q ref +ΔQ ref The time is the second time, and the difference between the second time and the first time is calculated to obtain the response reaching time.

[0098] In this way, the accuracy and reliability of the amplitude achievement rate and the response achievement time can be guaranteed, and the accuracy of determining the operation mode based on the amplitude achievement rate and the response achievement time can be improved.

[0099] Optionally, determining the operation mode of the new energy station according to the amplitude achievement rate and the response achievement time includes:

[0100] Determining whether a first condition corresponding to a pure DC operation mode is met, the first condition being that the amplitude achievement rate is greater than an achievement rate threshold, and the response achievement time is less than an achievement time threshold;

[0101] If not, determining that the operation mode of the new energy station is an AC / DC hybrid operation mode;

[0102] If so, a voltage disturbance is performed on the new energy station to obtain a voltage disturbance response result, which includes a voltage overshoot and a voltage steady-state error; and an operating mode of the new energy station is determined based on the voltage overshoot and the voltage steady-state error.

[0103] Specifically, the achievement rate threshold can be 95%. The duration threshold is a reference time after considering the reverse regulation effect of the AC system, which can be 1 second (s). Voltage steady-state error ε V Characterizes the steady-state voltage (reference voltage V ref ) and the total voltage deviation; voltage overshoot σ V It refers to the ratio of the actual voltage value to the total voltage.

[0104] In practical applications, the amplitude achievement rate η is determined Q and response time T Q Whether the first condition corresponding to the pure DC operation mode (OM_DC) is met, namely the amplitude achievement rate η Q Greater than the achievement rate threshold and the response achievement time T Q Less than the duration threshold.

[0105] If it is not satisfied, it means that the operation mode of the new energy station is AC / DC hybrid operation mode (OM_AC / DC); if it is satisfied, it preliminarily indicates that the operation mode of the new energy station may be OM_DC, but further verification is still needed, that is, voltage disturbance test.

[0106] Voltage disturbance test refers to AC voltage regulation and observation: adjusting the AC voltage reference value of the grid control, recording the overshoot and steady-state error of the AC voltage at the grid connection point, that is, the voltage overshoot and voltage steady-state error. Specifically, voltage disturbance injection is performed on the new energy station: a disturbance voltage ΔV of a set amplitude is injected into the new energy station side. ref , record the voltage overshoot σ at the grid connection point V and voltage steady-state error ε V .

[0107] Furthermore, according to the response to the injected voltage disturbance, the voltage overshoot σ V and voltage steady-state error ε V , and combined with the voltage damping characteristics under OM_AC / DC and OM_DC, the operation mode of the new energy station is determined.

[0108] In this way, the accuracy of the determined operation mode of the new energy station can be guaranteed through secondary verification of injected voltage disturbance.

[0109] Optionally, performing voltage disturbance on the new energy station to obtain a voltage disturbance response result includes:

[0110] Injecting a disturbance voltage into the reference voltage of the voltage control link of the flexible DC converter transformer for a second disturbance duration;

[0111] Monitoring the actual voltage value corresponding to the flexible DC converter transformer;

[0112] The voltage overshoot and the voltage steady-state error are determined according to the reference voltage, the disturbance voltage, and the actual voltage value.

[0113] Specifically, the disturbance voltage may be a step disturbance voltage.

[0114] In practical applications, the reference voltage V ref A disturbance voltage ΔV with a specific amplitude and a specific duration (second disturbance duration T2) is superimposed on the ref , that is, the disturbance mode is at the reference voltage V ref Superimposed ΔV ref Step disturbance, second disturbance duration T2. ​​The amplitude and duration of the disturbance voltage should be such that they do not cause voltage deviations that could trigger protection actions and block voltage regulation at the renewable energy station.

[0115] Furthermore, the disturbance voltage ΔV is tracked ref After the injection and system stability, the actual voltage value V corresponding to the flexible DC converter transformer is calculated based on the actual voltage value V and the reference voltage V. ref and disturbance voltage ΔV ref , calculate the voltage overshoot σ V and voltage steady-state error ε V .

[0116] In this way, the accuracy and reliability of voltage disturbance can be guaranteed.

[0117] Optionally, determining the voltage overshoot and the voltage steady-state error according to the reference voltage, the disturbance voltage, and the actual voltage value includes:

[0118] Calculating the sum of the reference voltage and the disturbance voltage to obtain a superimposed voltage;

[0119] The ratio by which the actual voltage value exceeds the superimposed voltage is determined as the voltage overshoot;

[0120] The deviation between the reference voltage and the superimposed voltage is determined as a voltage steady-state error.

[0121] In practical applications, the reference voltage V ref and disturbance voltage ΔV ref Add together to get the superimposed voltage (total voltage) V ref +ΔV ref . Further, calculate the actual voltage value V and the superimposed voltage Vref +ΔV ref The first difference is then calculated and the superimposed voltage V ref +ΔV ref The ratio of the voltage overshoot σ is obtained. V ; and superimpose the voltage V ref +ΔV ref With the reference voltage V ref The second difference, namely the disturbance voltage ΔV re , f With the superimposed voltage V ref +ΔV ref The ratio of the voltage steady-state error ε is determined as V .

[0122] In this way, the accuracy and reliability of the voltage overshoot and the voltage steady-state error can be guaranteed, and thus the accuracy of determining the operating mode based on the voltage overshoot and the voltage steady-state error can be improved.

[0123] Optionally, determining the operation mode of the new energy station according to the voltage overshoot and the voltage steady-state error includes:

[0124] determining whether a second condition corresponding to the pure DC operation mode is satisfied, the second condition being that the voltage overshoot is less than an overshoot threshold and the voltage steady-state error is less than a steady-state error threshold;

[0125] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0126] If so, the frequency disturbance is performed on the new energy station to obtain a frequency disturbance response result, which includes a frequency oscillation rate and a frequency tracking accuracy; and the operation mode of the new energy station is determined according to the frequency oscillation rate and the frequency tracking accuracy.

[0127] Specifically, the overshoot threshold can be 1%, the steady-state error threshold can be 0.5%, and the frequency tracking accuracy represents the root mean square error between the frequency measurement value and the total frequency.

[0128] In practical applications, the voltage overshoot σ is determined V and voltage steady-state error ε V Whether the second condition corresponding to OM_DC is met, that is, the voltage overshoot σ V Less than the overshoot threshold and the voltage steady-state error ε V Less than the steady-state error threshold.

[0129] If not, it means that the operation mode of the new energy station is OM_AC / DC; if satisfied, it preliminarily indicates that the operation mode of the new energy station may be OM_DC, but further verification is still needed, that is, setting up a frequency perturbation test.

[0130] Set up a frequency perturbation test, that is, perform frequency perturbations on the new energy station, observe and analyze the frequency dynamic behavior of the system, that is, the frequency oscillation rate A osc and frequency tracking accuracy δ f , and then according to the frequency oscillation rate A osc and frequency tracking accuracy δ f Finally determine the operation mode of new energy stations.

[0131] In this way, the accuracy of the determined operating mode of the new energy station can be guaranteed through three verifications of injected frequency disturbances.

[0132] Optionally, performing frequency disturbance on the new energy station to obtain a frequency disturbance response result includes:

[0133] Injecting a disturbance frequency into the reference frequency of the frequency control link of the flexible DC converter transformer;

[0134] monitoring a frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance is stabilized;

[0135] The frequency oscillation rate and the frequency tracking accuracy are determined according to the frequency steady-state amplitude, the reference frequency and the disturbance frequency.

[0136] Specifically, the disturbance frequency may be a step disturbance frequency. The frequency steady-state amplitude represents the stable amplitude of the frequency after the disturbance.

[0137] In practical applications, a disturbance frequency Δf with a specific amplitude and duration (third disturbance duration T3) is superimposed on the reference frequency ω of the frequency control link. ref The amplitude and duration of the disturbance frequency should be such as to avoid power oscillation and enable virtual inertia control of flexible DC.

[0138] Furthermore, the disturbance frequency Δf is tracked ref After the injection and system stabilization, the frequency steady-state amplitude f corresponding to the flexible DC converter transformer is calculated based on the frequency steady-state amplitude f, the reference frequency ω and the disturbance frequency Δf ref , calculate the frequency oscillation rate A osc and frequency tracking accuracy δ f .

[0139] In this way, the accuracy and reliability of frequency perturbation can be guaranteed.

[0140] Optionally, 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:

[0141] Calculating the sum of the reference frequency and the disturbance frequency to obtain a superposition frequency;

[0142] Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy;

[0143] The oscillation amplitude of the set frequency band is extracted by a fast Fourier transform algorithm to determine the frequency oscillation rate.

[0144] In practical applications, the reference frequency ω and the disturbance frequency Δf ref Add together to get the superimposed frequency (total frequency) ω+Δf ref . Further, calculate the frequency steady-state amplitude f and the superimposed frequency ω+Δf ref The root mean square error of the frequency tracking accuracy δ f ; and extract the oscillation amplitude of the set frequency band through the Fast Fourier Transform (FFT) algorithm to obtain the frequency oscillation rate A osc .

[0145] In this way, the accuracy and reliability of the frequency oscillation rate and the frequency tracking accuracy can be guaranteed, and thus the accuracy of determining the operating mode based on the frequency oscillation rate and the frequency tracking accuracy can be improved.

[0146] Optionally, determining the operation mode of the new energy station according to the frequency oscillation rate and the frequency tracking accuracy includes:

[0147] determining whether a third condition corresponding to the pure DC operation mode is satisfied, wherein the third condition is that the frequency oscillation rate is less than an oscillation rate threshold, and the frequency tracking accuracy is less than an accuracy threshold;

[0148] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0149] If so, it is determined that the operation mode of the new energy station is the pure DC operation mode.

[0150] In practical applications, if the frequency oscillation rate A osc and frequency tracking accuracy δ f If the set threshold is met and no power oscillation occurs, the new energy station is considered to be operating as OM_DC: Determine the frequency oscillation rate A osc and frequency tracking accuracy δ f Whether the third condition corresponding to OM_DC is met, that is, the frequency oscillation rate A oscLess than the oscillation rate threshold and the frequency tracking accuracy δ f Less than the accuracy threshold.

[0151] If it is not satisfied, it means that the operation mode of the new energy station is OM_AC / DC; if it is satisfied, it means that the operation mode of the new energy station may be OM_DC.

[0152] In this way, through triple verification, the accuracy of the determined operating mode of the new energy station is guaranteed.

[0153] Optionally, before performing reactive power disturbance on the new energy station and obtaining a power disturbance response result, the method further includes:

[0154] Acquiring grid dispatch information, where the grid dispatch information includes at least one of a new energy operation mode instruction, an AC switch status, and protection action behavior information;

[0155] Determining an operating mode of the new energy station based on the grid dispatch information;

[0156] If it is determined to be a failure, the steps before performing reactive power disturbance on the new energy station and obtaining the power disturbance response result are executed.

[0157] In practical applications, the operating mode of a renewable energy station can be determined by identifying at least one of the renewable energy operating mode instructions, AC switch status, and protection action information issued by the grid dispatcher. This can improve the efficiency of determining the operating mode of a renewable energy station.

[0158] For example, for a newly constructed new energy station in a scenario of combined AC and DC transmission, the new energy operation mode instruction and / or protection action behavior information includes an identification of the operation mode corresponding to the new energy station. Therefore, the new energy operation mode instruction and / or protection action behavior information can be obtained, and the identification of the operation mode can be extracted from the new energy operation mode instruction and / or protection action behavior information, and then the operation mode of the new energy station can be determined based on the identification.

[0159] For example, for the scenario where new energy stations transmit electricity through AC and DC, Figure 1 As shown, if the circuit breaker K1 is disconnected (AC switch state), the operation mode of the new energy station is OM_DC; if the circuit breaker K1 is closed (AC switch state), the operation mode of the new energy station is OM_AC / DC.

[0160] If the operation mode of the new energy station cannot be determined based on the grid dispatch information, the operation mode of the new energy station can be determined by performing reactive power disturbance on the new energy station.

[0161] The following combination Figure 3-Figure 9The method for determining the operating mode of the new energy station provided by the present invention is further explained.

[0162] See also Figure 3 , Figure 3 Schematic diagram of the flexible DC converter transformer injection disturbance provided by the present invention: wherein, P e and P ref are the output active power and active reference value of the flexible DC VSC respectively; KDp is the damping coefficient; J is the inertia coefficient; s is the pull 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 terminal voltage of the flexible DC VSC (i.e., the disturbance voltage ΔV ref );Q e and Q ref are the output reactive power and reactive reference value (benchmark reactive power) of the flexible DC VSC respectively; K q s is the integration factor; Dq is u o D and reference voltage V ref The superimposed voltage; abc represents the three-phase coordinate system, and dq represents the coordinate system consisting of the quadrature and direct axes. After processing through the voltage and frequency modulation stages, it enters the inner current control loop and is then processed by the voltage-controlled VSG, which uses PWM (Pulse Width Modulation) and transistors.

[0163] Among them, the disturbance reactive power ΔQ ref The reference reactive power Q superimposed on the voltage regulation control link (voltage regulation link) ref On the disturbance voltage ΔV ref The reference voltage V superimposed on the voltage regulation control link (voltage regulation link) ref On the perturbation frequency Δf ref Superimposed on the reference frequency ω of the frequency modulation control link (frequency modulation link).

[0164] First, the operation mode of new energy stations is obtained through power grid dispatch information.

[0165] If the operating mode of the new energy station cannot be directly obtained through the grid dispatch information, the "three-step disturbance injection-multi-dimensional response analysis" active detection process will be entered. The three-step disturbance injection-multi-dimensional response analysis means that reactive power disturbance, voltage disturbance and frequency disturbance are performed respectively, and the response results of each disturbance are analyzed.

[0166] Then, the VSC additional reactive power disturbance detection process is performed, that is, reactive power disturbance is performed.

[0167] The reference reactive power Q in the VSC voltage control linkref On the top, superimposed disturbance reactive power ΔQ ref =±5%Q n , where Q n Is the rated reactive power. Using the ramp injection method, the slope k=0.5%Q n / millisecond (ms), disturbance duration (first disturbance duration) T1=2s.

[0168] Setting η Q >95% and T Q Under the working condition of <1s, that is, the achievement rate threshold is 95% and the achievement time threshold is 1s, the operation mode of the new energy station is OM_DC, otherwise it is OM_AC / DC.

[0169] See also Figure 4 and Figure 5 , Figure 4 This is the reactive power response waveform of the new energy station grid connection point provided by the present invention in pure DC operation mode. Figure 5 This is the reactive power response waveform of the new energy station grid connection point provided by the present invention in the AC / DC hybrid operation mode: the injected disturbance reactive power ΔQ ref After that, η Q =100%, T Q =100ms. Therefore, it is preliminarily determined that the operation of the new energy station is OM_DC. The injected disturbance reactive power ΔQ ref After that, the fluctuation rate of reactive power is less than the grid allowable value ≤3%, and the new energy grid disconnection protection and voltage flicker are not triggered. Figure 4 and Figure 5 In the middle, the dotted line represents Q ref The corresponding response waveform, the solid line represents the response waveform corresponding to Q, Q=ΔQ ref +Q ref .

[0170] Next, the VSC additional voltage disturbance detection process is performed, that is, voltage disturbance is performed.

[0171] The reference voltage V in the VSC voltage control link ref On the superimposed disturbance voltage ΔV ref = ±5% Vn, where V n is the rated voltage, and the disturbance duration (second disturbance duration) T2=5s.

[0172] When hybrid transmission is set (new energy station operates as OM_AC / DC), due to the reverse regulation effect, σ V >3%, pure DC transmission (new energy station operates as OM_DC) V <1%; the integral link of the network control is set to eliminate the steady-state error, and the pure DC output is ε V<0.5%, but due to the difference in AC line impedance, ε V >1%. That is, the overshoot threshold is 1% and the steady-state error threshold is 0.5%.

[0173] See also Figure 6 and Figure 7 , Figure 6 This is the voltage response waveform diagram of the new energy station grid connection point provided by the present invention in pure DC operation mode. Figure 7 This is the voltage response waveform of the new energy station grid connection point provided by the present invention in the AC / DC hybrid operation mode: the injected disturbance voltage ΔV ref Then, calculate the voltage overshoot σ V <1% and 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 voltage steady-state error ε V If it is smaller than the reference value after considering the influence of voltage reverse regulation of the AC system, it is preliminarily judged that the operation mode of the new energy station is OM_DC. Figure 6 and Figure 7 In the figure, the dotted line represents V ref The corresponding response waveform, the solid line represents the response waveform corresponding to V, V = ΔV ref +V ref .

[0174] Finally, VSC frequency disturbance detection is performed, that is, frequency disturbance is performed.

[0175] If the operation mode of the new energy station is determined to be OM_DC based on the power disturbance response results and the voltage disturbance response results, a frequency perturbation test is set.

[0176] In the VSC frequency control link, the reference frequency ω (f ref ), a step disturbance frequency Δf with a specific amplitude and duration (third disturbance duration) is superimposed on ref = ±0.05 Hz; Δf ref The amplitude and duration of the disturbance should be adjusted to avoid power oscillation and enable the virtual inertia control of the flexible DC. The virtual inertia control of the flexible DC is enabled during the disturbance, and the inertia time constant H=3s.

[0177] The oscillation amplitude of the 0.01-2 Hz frequency band is extracted by FFT to obtain the frequency oscillation rate A osc When setting hybrid transmission (new energy station operation is OM_AC / DC) osc >2%, pure DC transmission (new energy station operates as OM_DC) A osc <0.5%. When setting mixed delivery f>0.02Hz, when pure DC is sent out f <0.005 per unit (Pu). That is, the oscillation rate threshold is 0.5% and the accuracy threshold is 0.005Pu.

[0178] See also Figure 8 and Figure 9 , Figure 8 This 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. Figure 9 This is the waveform diagram of the frequency response and power response of the new energy station grid connection point provided by the present invention in the AC / DC hybrid operation mode: frequency oscillation rate A osc <0.3%, frequency tracking accuracy δ f <0.003Pu, that is, the frequency oscillation rate and frequency tracking accuracy meet the set threshold, and no power oscillation occurs, then the operation mode of the new energy station is considered to be OM_DC. Figure 8 and Figure 9 In the figure, the upper figure is the frequency response waveform, the lower figure is the power response waveform, and the dotted line in the upper figure represents f ref The corresponding response waveform, the solid line represents the response waveform corresponding to f, f=Δf ref +f ref .

[0179] This embodiment of the present invention implements hierarchical disturbance injection through a flexible DC control system (flexible DC converter transformer): First, disturbance reactive power is injected into the renewable energy station side, and the amplitude achievement rate and response achievement time at the grid connection point are monitored in real time. A step disturbance voltage is simultaneously injected to extract voltage overshoot and voltage steady-state error. An initial judgment is made based on the differences in voltage damping ratios (achievement rate threshold, achievement time threshold, overshoot threshold, and steady-state error threshold) between pure DC operation and AC / DC hybrid operation. If pure DC operation is determined, a disturbance frequency is injected, and re-verification is achieved through frequency oscillation rate and frequency tracking accuracy. While ensuring steady-state system operation, the operating mode of the renewable energy station is actively detected through non-intrusive disturbances, significantly improving the control stability and oscillation suppression capabilities of the flexible DC converter transformer.

[0180] The following describes the device for determining the operating mode of a new energy station provided by the present invention. The device for determining the operating mode of a new energy station described below and the method for determining the operating mode of a new energy station described above can refer to each other.

[0181] See also Figure 10 , Figure 10 This is a schematic diagram of the structure of the device for determining the operation mode of the new energy station provided by the present invention. Figure 10 As shown, the device includes the following:

[0182] The disturbance module 1001 is configured to perform reactive power disturbance on the new energy station and obtain a power disturbance response result, wherein the power disturbance response result includes an amplitude achievement rate and a response achievement time;

[0183] The determination module 1002 is configured to determine the operation mode of the new energy station according to the amplitude achievement rate and the response achievement time.

[0184] Optionally, the disturbance module 1001 is specifically configured to:

[0185] Adopting the ramp injection method, the disturbance reactive power is injected into the reference reactive power of the voltage control link of the flexible DC converter transformer according to the set slope and lasts for the first disturbance duration;

[0186] Monitoring the actual value of reactive power corresponding to the flexible DC converter transformer;

[0187] 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.

[0188] Optionally, the disturbance module 1001 is specifically configured to:

[0189] Calculating the sum of the reference reactive power and the disturbance reactive power to obtain superimposed reactive power;

[0190] Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate;

[0191] Obtaining a first time of injecting the disturbance reactive power, and determining a second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power;

[0192] The time interval between the first time and the second time is determined as the response achievement duration.

[0193] Optionally, the determining module 1002 is specifically configured to:

[0194] Determining whether a first condition corresponding to a pure DC operation mode is met, the first condition being that the amplitude achievement rate is greater than an achievement rate threshold, and the response achievement time is less than an achievement time threshold;

[0195] If not, determining that the operation mode of the new energy station is an AC / DC hybrid operation mode;

[0196] If so, a voltage disturbance is performed on the new energy station to obtain a voltage disturbance response result, which includes a voltage overshoot and a voltage steady-state error; and an operating mode of the new energy station is determined based on the voltage overshoot and the voltage steady-state error.

[0197] Optionally, the determining module 1002 is specifically configured to:

[0198] Injecting a disturbance voltage into the reference voltage of the voltage control link of the flexible DC converter transformer for a second disturbance duration;

[0199] Monitoring the actual voltage value corresponding to the flexible DC converter transformer;

[0200] The voltage overshoot and the voltage steady-state error are determined according to the reference voltage, the disturbance voltage, and the actual voltage value.

[0201] Optionally, the determining module 1002 is specifically configured to:

[0202] Calculating the sum of the reference voltage and the disturbance voltage to obtain a superimposed voltage;

[0203] The ratio by which the actual voltage value exceeds the superimposed voltage is determined as the voltage overshoot;

[0204] The deviation between the reference voltage and the superimposed voltage is determined as a voltage steady-state error.

[0205] Optionally, the determining module 1002 is specifically configured to:

[0206] determining whether a second condition corresponding to the pure DC operation mode is satisfied, the second condition being that the voltage overshoot is less than an overshoot threshold and the voltage steady-state error is less than a steady-state error threshold;

[0207] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0208] If so, the frequency disturbance is performed on the new energy station to obtain a frequency disturbance response result, which includes a frequency oscillation rate and a frequency tracking accuracy; and the operation mode of the new energy station is determined according to the frequency oscillation rate and the frequency tracking accuracy.

[0209] Optionally, the determining module 1002 is specifically configured to:

[0210] Injecting a disturbance frequency into the reference frequency of the frequency control link of the flexible DC converter transformer;

[0211] monitoring a frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance is stabilized;

[0212] The frequency oscillation rate and the frequency tracking accuracy are determined according to the frequency steady-state amplitude, the reference frequency and the disturbance frequency.

[0213] Optionally, the determining module 1002 is specifically configured to:

[0214] Calculating the sum of the reference frequency and the disturbance frequency to obtain a superposition frequency;

[0215] Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy;

[0216] The deviation between the reference voltage and the superimposed voltage is determined as a voltage steady-state error.

[0217] The oscillation amplitude of the set frequency band is extracted by a fast Fourier transform algorithm to determine the frequency oscillation rate.

[0218] Optionally, the determining module 1002 is specifically configured to:

[0219] determining whether a third condition corresponding to the pure DC operation mode is satisfied, wherein the third condition is that the frequency oscillation rate is less than an oscillation rate threshold, and the frequency tracking accuracy is less than an accuracy threshold;

[0220] If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode;

[0221] If so, it is determined that the operation mode of the new energy station is the pure DC operation mode.

[0222] Optionally, the device further includes an acquisition module configured to:

[0223] Acquiring grid dispatch information, where the grid dispatch information includes at least one of a new energy operation mode instruction, an AC switch status, and protection action behavior information;

[0224] Determining an operating mode of the new energy station based on the grid dispatch information;

[0225] If it is determined to be a failure, the steps before performing reactive power disturbance on the new energy station and obtaining the power disturbance response result are executed.

[0226] Figure 11 Schematic diagram of the structure of the electronic device provided by the present invention. Figure 11 As shown, the electronic device may include: a processor 1110, a communication interface 1120, a memory 1130, and a communication bus 1140, wherein the processor 1110, the communication interface 1120, and the memory 1130 communicate with each other via the communication bus 1140. The processor 1110 may call the logic instructions in the memory 1130 to execute the method for determining the operating mode of the new energy station.

[0227] Furthermore, the logic instructions in the aforementioned memory 1130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0228] On the other hand, the present invention also provides a computer program product, which 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 operating mode of the new energy station provided by the above methods.

[0229] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for determining the operating mode of a new energy station provided by the above methods.

[0230] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0231] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0232] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for determining the operation mode of a new energy station, characterized in that: include: Performing 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; determining an operation mode of the new energy station according to the amplitude achievement rate and the response achievement time; The performing of reactive power disturbance on the new energy station to obtain a power disturbance response result includes: Adopting the ramp injection method, the disturbance reactive power is injected into the reference reactive power of the voltage control link of the flexible DC converter transformer according to the set slope and lasts for the first disturbance duration; Monitoring the actual value of reactive power corresponding to the flexible DC converter transformer; Calculating the sum of the reference reactive power and the disturbance reactive power to obtain superimposed reactive power; Determine the ratio of the reference reactive power to the superimposed reactive power as the amplitude achievement rate; Obtaining a first time of injecting the disturbance reactive power, and determining a second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power; The time interval between the first time and the second time is determined as the response achievement duration.

2. The method for determining the operation mode of a new energy station according to claim 1, characterized in that: The determining of the operation mode of the new energy station according to the amplitude achievement rate and the response achievement time includes: Determining whether a first condition corresponding to a pure DC operation mode is met, the first condition being that the amplitude achievement rate is greater than an achievement rate threshold, and the response achievement time is less than an achievement time threshold; If not, determining that the operation mode of the new energy station is an AC / DC hybrid operation mode; If so, a voltage disturbance is performed on the new energy station to obtain a voltage disturbance response result, which includes a voltage overshoot and a voltage steady-state error; and an operating mode of the new energy station is determined based on the voltage overshoot and the voltage steady-state error.

3. The method for determining the operation mode of a new energy station according to claim 2, characterized in that: The performing voltage disturbance on the new energy station to obtain a voltage disturbance response result includes: Injecting a disturbance voltage into the reference voltage of the voltage control link of the flexible DC converter transformer 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; The ratio by which the actual voltage value exceeds the superimposed voltage is determined as the voltage overshoot; The deviation between the reference voltage and the superimposed voltage is determined as a voltage steady-state error.

4. The method for determining the operation mode of a new energy station according to claim 2, characterized in that: The determining the operation mode of the new energy station according to the voltage overshoot and the voltage steady-state error includes: determining whether a second condition corresponding to the pure DC operation mode is satisfied, the second condition being that the voltage overshoot is less than an overshoot threshold and the voltage steady-state error is less than a steady-state error threshold; If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode; If so, the frequency disturbance is performed on the new energy station to obtain a frequency disturbance response result, which includes a frequency oscillation rate and a frequency tracking accuracy; and the operation mode of the new energy station is determined according to the frequency oscillation rate and the frequency tracking accuracy.

5. The method for determining the operation mode of a new energy station according to claim 4, characterized in that: The performing frequency disturbance on the new energy station to obtain a frequency disturbance response result includes: Injecting a disturbance frequency into the reference frequency of the frequency control link of the flexible DC converter transformer; monitoring a frequency steady-state amplitude corresponding to the flexible DC converter transformer after the disturbance is stabilized; Determining 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: Calculating the sum of the reference frequency and the disturbance frequency to obtain a superposition frequency; Determine the root mean square error between the frequency steady-state amplitude and the superimposed frequency as the frequency tracking accuracy; The oscillation amplitude of the set frequency band is extracted by a fast Fourier transform algorithm to determine the frequency oscillation rate.

6. The method for determining the operation mode of a new energy station according to claim 4, characterized in that: The determining the operation mode of the new energy station according to the frequency oscillation rate and the frequency tracking accuracy includes: determining whether a third condition corresponding to the pure DC operation mode is satisfied, wherein the third condition is that the frequency oscillation rate is less than an oscillation rate threshold, and the frequency tracking accuracy is less than an accuracy threshold; If not, determining that the operation mode of the new energy station is the AC / DC hybrid operation mode; If so, it is determined that the operation mode of the new energy station is the pure DC operation mode.

7. The method for determining the operation mode of a new energy station according to any one of claims 1 to 6, characterized in that: Before performing reactive power disturbance on the new energy station and obtaining the power disturbance response result, the method further includes: Acquiring grid dispatch information, where the grid dispatch information includes at least one of a new energy operation mode instruction, an AC switch status, and protection action behavior information; Determining an operating mode of the new energy station based on the grid dispatch information; If it is determined to be a failure, the steps before performing reactive power disturbance on the new energy station and obtaining the power disturbance response result are executed.

8. A device for determining the operation mode of a new energy station, characterized in that: include: A disturbance module is configured to perform reactive power disturbance on the new energy station and obtain a power disturbance response result, wherein the power disturbance response result includes an amplitude achievement rate and a response achievement time; a determination module configured to determine an operation mode of the new energy station according to the amplitude achievement rate and the response achievement time; The disturbance module is specifically configured to adopt a ramp injection method to inject disturbance reactive power according to a set slope on the reference reactive power of the voltage control link of the flexible DC converter transformer, and continue for a first disturbance duration; monitor the actual value of the reactive power corresponding to the flexible DC converter transformer; 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 of injecting the disturbance reactive power, and determine the second time when the actual value of the reactive power reaches the superimposed reactive power from the steady-state reactive power; and determine the time interval between the first time and the second time as the response achievement duration.

Images