Subsynchronous oscillation monitoring system and method for wind power generation system

Abstract

The invention provides a subsynchronous oscillation monitoring system and method for a wind power generation system, and the system comprises a signal collection module which is used for obtaining an output current parameter and a power grid interface voltage parameter in a target wind power plant region, and generating a current and voltage monitoring value; the feature extraction module is used for extracting oscillation frequency parameters and oscillation feature parameter values based on the current and voltage monitoring values; the dynamic threshold module is used for acquiring a power grid load parameter and a wind speed parameter and generating a dynamic threshold parameter value through weighted calculation; the state judgment module is used for performing state logic judgment based on the oscillation frequency parameter and the dynamic threshold value to obtain an oscillation state judgment value; and the result output module is used for generating a monitoring alarm signal value based on the oscillation state judgment value. According to the method, dynamic environment response and accurate feature extraction can be combined, the monitoring sensitivity and reliability are enhanced, the misjudgment probability caused by external interference is reduced, the protection action accuracy is optimized, and stable operation of a power grid is guaranteed.

Description

Technical Field

[0001] This application belongs to the field of power system safety and stable operation technology, and particularly relates to the field of grid stability analysis and fault diagnosis after new energy power generation is connected to the grid. In particular, it relates to a subsynchronous oscillation monitoring system and method for wind power generation systems. Background Technology

[0002] The large-scale integration of renewable energy sources, such as wind power, into the power grid is a key aspect of renewable energy grid integration technology. The core of this technology lies in safely and reliably connecting renewable energy sources like wind power to the existing power grid while maintaining the overall stable operation of the power system. This process requires addressing numerous challenges arising from the intermittency and volatility of renewable energy sources, such as voltage fluctuations, frequency deviations, and power oscillations. Among these, SSO (Subsynchronous Oscillation), an abnormal oscillation phenomenon with a frequency lower than the system synchronization frequency, has become a critical technical challenge threatening the stable operation of wind farms and the power grid. Failure to effectively monitor and suppress it can lead to torsional vibration damage to generator shafts, malfunctions of protection devices, and even large-scale power outages.

[0003] Currently, wind power subsynchronous oscillation monitoring systems are the main technical means to address this problem. Their general technical solutions typically include: real-time acquisition of electrical data at the grid connection point using current and voltage sensors; feature extraction of the data using signal processing algorithms (such as Fourier transform and Prony analysis) to calculate key parameters such as the oscillation frequency and amplitude; and finally, comparison and analysis of the calculated oscillation parameters with preset safety thresholds to determine whether the system is in a dangerous oscillation state and whether to issue an early warning.

[0004] However, existing monitoring technologies still have significant shortcomings. Their reliability, accuracy, and adaptability are insufficient to meet the needs of complex and ever-changing real-world grid connection scenarios. Specific deficiencies are as follows:

[0005] (1) The threshold judgment mechanism is rigid and lacks dynamic adaptability: Existing systems generally rely on fixed preset thresholds to judge oscillation risks. Such static thresholds cannot effectively respond to real-time conditions such as drastic changes in wind speed, fluctuations in power grid load, and changes in system operation mode, resulting in monitoring results deviating from the actual risk level. Setting the threshold too low can easily generate false alarms, while setting it too high may miss the real risks. There is a lack of a dynamic threshold response mechanism that is linked to environmental parameters.

[0006] (2) The feature extraction method is crude, and local abnormal features are easily masked: Existing feature extraction algorithms mostly use data within a wide time window for overall calculation (e.g., calculating the average amplitude over a period of time). This method smooths out short but violent extreme fluctuations in the data and cannot effectively distinguish and capture local abnormal features within the key time window, resulting in a sluggish judgment of the oscillation initiation and deterioration process, and the processing method is too crude.

[0007] (3) Insufficient data acquisition synchronization leads to distorted analysis basis: In the data acquisition stage, the existing system does not have strict requirements for the synchronization of timestamps of current and voltage signals. The delay caused by path differences during signal transmission will cause data pairing deviation. This "data asynchrony" problem makes all subsequent feature extraction and calculation analysis based on distorted data, which seriously affects the accuracy of the final monitoring results.

[0008] In summary, existing subsynchronous oscillation monitoring systems, due to their static and singular operating mode, lack adaptability to the complex dynamic processes of the power grid under high-proportion renewable energy integration, resulting in limited monitoring accuracy. This not only increases the risk of malfunction or failure of protection devices but also poses a potential threat to the continuous power supply reliability of the entire power system.

[0009] Therefore, there is an urgent need for a high-precision subsynchronous oscillation monitoring solution that can adapt to real-time operating conditions, extract fine features, and ensure data synchronization. Summary of the Invention

[0010] The purpose of this application is to provide a subsynchronous oscillation monitoring system and method for wind power generation systems, which solves the technical problems of low monitoring accuracy, poor adaptability and high risk of protection malfunction caused by existing wind power subsynchronous oscillation monitoring systems relying on fixed thresholds, crude feature extraction methods and asynchronous data acquisition.

[0011] In a first aspect, this application provides a subsynchronous oscillation monitoring system for a wind power generation system. The system includes: a signal acquisition module, a feature extraction module, a dynamic threshold module, a state judgment module, and a result output module. The signal acquisition module is used to acquire output current parameters and grid interface voltage parameters within a target wind farm area, and integrate the output current parameters and grid interface voltage parameters to generate current and voltage monitoring values. The current and voltage monitoring values ​​include instantaneous current values ​​and instantaneous voltage values. The feature extraction module is connected to the signal acquisition module and is used to perform feature extraction based on the current and voltage monitoring values ​​to obtain oscillation frequency parameters and oscillation characteristic parameter values. The dynamic threshold module... The module is connected to the feature extraction module and is used to acquire grid load parameters and wind speed parameters. By weighting the grid load parameters and wind speed parameters, a dynamic threshold parameter value is generated. The state judgment module is connected to the dynamic threshold module and is used to determine whether the oscillation frequency parameter is greater than a zero threshold based on the oscillation frequency parameter and the dynamic threshold. Based on the judgment condition, a state logic judgment is performed to obtain an oscillation state judgment value. The result output module is connected to the state judgment module and is used to generate an indication signal based on the oscillation state judgment value. The indication signal is then transmitted to the protection device interface to generate a monitoring alarm signal value, thereby realizing the subsynchronous oscillation monitoring of the wind power generation system.

[0012] In one implementation of the first aspect, the signal acquisition module includes: a current acquisition submodule, a voltage acquisition submodule, and a data integration submodule; the current acquisition submodule is used to acquire the output current parameters of the wind farm, acquire instantaneous current values ​​in real time through a current sensor, record the sampling timestamp and the current value sequence, and generate current sampling values; the voltage acquisition submodule is used to acquire the grid interface voltage parameters, acquire instantaneous voltage values ​​in real time through a voltage monitoring device, record the sampling timestamp and the voltage value sequence, and generate voltage acquisition values; the data integration submodule is used to align the current value sequence and the voltage value sequence according to the same timestamp based on the current sampling values ​​and the voltage acquisition values, integrate them into a time-synchronized current and voltage data pair set, and generate current and voltage monitoring values.

[0013] In one implementation of the first aspect, the feature extraction module includes: a frequency extraction submodule, an amplitude extraction submodule, and a feature integration submodule; the frequency extraction submodule is used to extract a current parameter sequence based on the current and voltage monitoring values, calculate the algebraic difference between the current parameter sequence and the system synchronization frequency reference value, and generate oscillation frequency data; the amplitude extraction submodule is used to extract a voltage parameter sequence based on the current and voltage monitoring values, calculate the maximum absolute value of the voltage parameter sequence relative to the rated voltage within a preset time window, and generate oscillation amplitude data; the feature integration submodule is used to integrate the oscillation frequency data and the oscillation amplitude data into a parameter pair set, thereby obtaining oscillation feature parameter values.

[0014] In one implementation of the first aspect, the dynamic threshold module includes: a load parameter submodule, a wind speed change submodule, and a threshold synthesis submodule; the load parameter submodule is used to acquire power grid load parameters, detect load values ​​through power grid monitoring equipment, calculate a ratio result by algebraic division of the load value and a preset benchmark load value, and generate a load ratio value; the wind speed change submodule is used to acquire wind speed parameters, collect wind speed value sequences through meteorological sensors, calculate the difference between the wind speed value at the current sampling point and the wind speed value at the previous sampling point, and then generate a rate of change result based on the difference and a preset sampling time interval, and generate a wind speed rate of change value; the threshold synthesis submodule is used to perform linear multiplication of the load ratio value and the wind speed rate of change value according to a preset weighting coefficient, and then perform addition to generate a synthesized value, and generate a dynamic threshold parameter value.

[0015] In one implementation of the first aspect, the state determination module includes: a feature parameter extraction submodule, a comparison operation submodule, and a state determination submodule; the feature parameter extraction submodule is used to extract an oscillation frequency parameter and an oscillation amplitude parameter based on the oscillation feature parameter value, and integrate the oscillation frequency parameter and the oscillation amplitude parameter into a parameter pair set to generate a frequency amplitude pair value; the comparison operation submodule is used to extract the oscillation frequency parameter based on the frequency amplitude pair value, call a dynamic threshold parameter value, and simultaneously perform data calculation based on the oscillation frequency parameter and the dynamic threshold parameter value to obtain a difference result, thereby generating a frequency difference value; the state determination submodule is used to determine whether the frequency difference value is greater than a zero threshold based on the frequency difference value to generate a logical judgment result and generate an oscillation state determination value.

[0016] In one implementation of the first aspect, the result output module includes: a status generation submodule, a transmission execution submodule, and an alarm output submodule; the status generation submodule is used to obtain a logic signal value based on the oscillation status determination value, and to make a judgment based on the logic signal value to obtain a status signal value; the transmission execution submodule is used to transmit the status signal value to the protection device coordination interface through an optical fiber interface, generate a transmission confirmation flag after the signal transmission is completed, and obtain a transmission completion value; the alarm output submodule is used to obtain a monitoring alarm signal value based on the transmission completion value and generate a monitoring alarm signal value.

[0017] In one implementation of the first aspect, the signal is further configured to be set to a high level when the oscillation state determination value is true, and to be set to a high level when the oscillation state determination value is false.

[0018] In one implementation of the first aspect, the system further includes: triggering the protection device to perform circuit breaker tripping action based on the monitoring alarm signal value, simultaneously activating the data recording unit to store the full process parameters of the oscillation event, sending an alarm notification to the central monitoring system, and generating an event analysis report for operation and maintenance personnel to access.

[0019] Secondly, this application provides a method for monitoring subsynchronous oscillations in a wind power generation system. The method includes: acquiring output current parameters and grid interface voltage parameters of a target wind farm, as well as grid load parameters and wind speed parameters; performing data processing based on the output current parameters and grid interface voltage parameters to obtain current and voltage monitoring values; performing feature extraction based on the current and voltage monitoring values ​​to obtain oscillation feature parameter values; obtaining dynamic threshold parameter values ​​based on the grid load parameters and wind speed parameters; performing state judgment based on the oscillation frequency parameter in the oscillation feature parameter values ​​to obtain an oscillation state determination value; and obtaining a monitoring alarm signal value based on the oscillation state determination value.

[0020] In one implementation of the second aspect, the process of determining the oscillation state based on the oscillation frequency parameter in the oscillation characteristic parameter value to obtain the oscillation state determination value includes: extracting the oscillation frequency parameter based on the oscillation characteristic parameter value; integrating the oscillation frequency parameter to obtain a frequency amplitude pair value; extracting the oscillation frequency parameter based on the frequency amplitude pair value; calculating the difference between the dynamic threshold parameter value and the oscillation frequency parameter to obtain a frequency difference value; performing a logical judgment based on the frequency difference value, generating a logical judgment result, and obtaining the oscillation state determination value.

[0021] As described above, the subsynchronous oscillation monitoring system and control method for wind power generation systems described in this application have the following beneficial effects:

[0022] The subsynchronous oscillation monitoring system for wind power generation systems provided in this application can synchronously collect current and voltage data to form a time-aligned set, eliminate signal transmission delay errors, improve data integrity, calculate the real-time algebraic difference between the current sequence and the system frequency to directly reflect frequency offset characteristics, avoid feature ambiguity caused by traditional averaging, identify the maximum fluctuation amplitude of the voltage sequence relative to the rated value within a specific time window, focus on key anomalies, replace wide-range analysis, improve feature extraction accuracy, dynamically fuse load ratio and wind speed change rate, generate adaptive thresholds based on actual impact ratios, match changes in operating conditions in real time, perform direct algebraic comparisons between frequency parameters and dynamic thresholds, determine whether the deviation exceeds the zero reference, output clear logical status, and ensure a transparent and verifiable process. The overall processing logic combines dynamic environmental response and accurate feature extraction to enhance monitoring sensitivity and reliability, reduce the probability of misjudgment caused by external interference, optimize the accuracy of protection actions, and ensure stable operation of the power grid. Attached Figure Description

[0023] Figure 1 The diagram shown is a schematic representation of the overall structural framework of the subsynchronous oscillation monitoring system for wind power generation systems described in this application embodiment.

[0024] Figure 2 The diagram shown is a structural schematic of the subsynchronous oscillation monitoring system for wind power generation systems described in this application embodiment.

[0025] Figure 3 The diagram shown is a schematic representation of the main structure of the subsynchronous oscillation monitoring system for wind power generation systems described in this application embodiment.

[0026] Figure 4 The diagram shown is a schematic diagram of the state judgment module in one embodiment of the subsynchronous oscillation monitoring system for wind power generation systems described in this application.

[0027] Figure 5 The diagram shown is a schematic overall flow chart of the subsynchronous oscillation monitoring method for wind power generation systems described in this application embodiment.

[0028] Figure 6 The diagram shown is S2 of one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application.

[0029] Figure 7 The diagram shown is S3 of one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application.

[0030] Figure 8 The diagram shown is a schematic diagram of the S4 process in one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application.

[0031] Figure 9 The diagram shown is a schematic S5 flow chart of the subsynchronous oscillation monitoring method for wind power generation systems described in this application.

[0032] Figure 10 The diagram shown is a schematic diagram of S6 in one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application.

[0033] Component designation explanation

[0034] 1 Subsynchronous Oscillation Monitoring System for Wind Power Generation Systems

[0035] 11 Signal Acquisition Module

[0036] 111 Current Acquisition Submodule

[0037] 112 Voltage Acquisition Submodule

[0038] 113 Data Integration Submodule

[0039] 12 Feature Extraction Module

[0040] 121 Frequency Extraction Submodule

[0041] 122 Amplitude Extraction Submodule

[0042] 123 Feature Integration Submodule

[0043] 13 Dynamic Threshold Module

[0044] 131 Load Parameter Submodule

[0045] 132 Wind Speed ​​Change Submodule

[0046] 133 Threshold Synthesis Submodule

[0047] 14. Status Judgment Module

[0048] 141 Feature Parameter Extraction Submodule

[0049] 142 Comparison Operation Submodule

[0050] 143 State Determination Submodule

[0051] 15 Result Output Module

[0052] 151 State Generation Submodule

[0053] 152 Transmission Execution Submodule

[0054] 153 Alarm Output Submodule

[0055] 2 servers Detailed Implementation

[0056] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0057] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0058] The subsynchronous oscillation monitoring system for wind power generation systems provided in this application can respond to load fluctuations and wind speed changes in real time through a dynamic threshold mechanism, eliminating the problem of rigid fixed thresholds. Algebraic difference calculation avoids feature ambiguity, time window extreme value extraction improves feature recognition accuracy, and timestamp alignment eliminates data offset errors. This significantly reduces the probability of misjudgment under complex operating conditions, enhances monitoring sensitivity and protection accuracy, and ensures stable operation of the power grid.

[0059] The subsynchronous oscillation monitoring system for wind power generation systems provided in the following embodiments of this application solves the technical problems of low monitoring accuracy, poor adaptability, and high risk of protection malfunction caused by existing wind power subsynchronous oscillation monitoring systems, which rely on fixed thresholds, have coarse feature extraction methods, and have asynchronous data acquisition.

[0060] like Figure 1 As shown in the schematic diagram of the overall structural framework of the subsynchronous oscillation monitoring system for wind power generation systems described in this application embodiment, it specifically includes: a signal acquisition module 11, a feature extraction module 12, a dynamic threshold module 13, a state judgment module 14, and a result output module 15. The subsynchronous oscillation monitoring system 1 for wind power generation systems provided in the following embodiments of this application, through the coordinated operation of these five modules, can combine dynamic environmental response and accurate feature extraction to enhance monitoring sensitivity and reliability, reduce the probability of misjudgment caused by external interference, optimize the accuracy of protection actions, and ensure the stable operation of the power grid.

[0061] Please see Figures 2 to 4The diagrams shown are: a structural schematic diagram of the subsynchronous oscillation monitoring system for wind power generation system according to an embodiment of this application; a main structural schematic diagram of the subsynchronous oscillation monitoring system for wind power generation system according to an embodiment of this application; and a schematic diagram of the state judgment module of the subsynchronous oscillation monitoring system for wind power generation system according to an embodiment of this application.

[0062] In this embodiment, the signal acquisition module 11 is used to acquire the output current parameters and grid interface voltage parameters within the target wind farm area, and integrate the output current parameters and grid interface voltage parameters to generate current and voltage monitoring values. The current and voltage monitoring values ​​include instantaneous current values ​​and instantaneous voltage values.

[0063] Specifically, the signal acquisition module 11 acquires the output current parameters of the wind farm in real time through the current sensor and the voltage parameters of the grid interface in real time through the voltage monitoring device. The current parameters and voltage parameters are aligned according to the time series and integrated into a set of current and voltage data pairs with the same timestamp to generate current and voltage monitoring values.

[0064] The signal acquisition module 11 includes: a current acquisition submodule 111, a voltage acquisition submodule 112, and a data integration submodule 113. The current acquisition submodule 111 is used to acquire the output current parameters of the wind farm, collect instantaneous current values ​​in real time using a current sensor, record the sampling timestamp and current value sequence, and generate current sample values.

[0065] Specifically, the current acquisition submodule 111 is used to acquire the output current parameters of the wind farm, collect instantaneous current values ​​in real time through a current sensor, record the sampling timestamp and current value sequence, and generate current sampling values.

[0066] Specifically, the current acquisition submodule 111 acquires the output current parameters of the wind farm, using a 2000A range Hall current sensor to acquire instantaneous current values ​​at a sampling rate of 10kHz. For example, at a certain moment, the sensor outputs an analog signal, which is converted into a digital value of 1532.7 (corresponding to an actual current value of 1532.7A) by a 16-bit ADC. The sampling timestamp 20250731_142030_0150 (year, month, day, hour, minute, second, millisecond) and the current current value are recorded simultaneously. Continuous sampling forms a sequence [1532.7, 1531.8, 1533.5...], generating current sample values.

[0067] The voltage acquisition submodule 112 is used to acquire grid interface voltage parameters, collect instantaneous voltage values ​​in real time through a voltage monitoring device, record sampling timestamps and voltage value sequences, and generate voltage acquisition values.

[0068] For example, the voltage acquisition submodule acquires the grid interface voltage parameters and collects the instantaneous voltage value of the 220kV system through a 0.2-level precision voltage transformer. For example, the raw signal acquired at time t = 20250731_142030_0150 is filtered and converted into a digital quantity of 226.4 (unit: kV). The same timestamp and voltage value sequence [226.4, 226.1, 225.8...] are recorded. The voltage monitoring device collects the data every 1ms and generates the voltage acquisition value.

[0069] The data integration submodule 113 is used to align the current value sequence and the voltage value sequence with the same timestamp based on the current sampling value and the voltage acquisition value, integrate them into a time-synchronized current and voltage data pair set, and generate current and voltage monitoring values.

[0070] Specifically, the data integration submodule 113 calls the current sampling value sequence and the voltage acquisition value sequence, aligning the data based on the timestamp. For example, when the current sequence timestamp t1 = 20250731_142030_0150 corresponds to a value of 1532.7A, and the nearest neighbor timestamp of the voltage sequence t2 = 20250731_142030_0149 (difference 0.1ms) corresponds to a value of 225.8kV, linear interpolation is used. Calculate the voltage value at time t1: Vt1 = 225.8 + (226.4 - 225.8) × (0.1 / 1.0) = 225.86 kV. Generate the current and voltage data pair (1532.7 A, 225.86 kV). Iterate through all time points to form a set of synchronous data pairs {(1531.8 A, 226.12 kV), (1533.5 A, 225.94 kV)...}, and generate the current and voltage monitoring values.

[0071] In one embodiment, the feature extraction module 12 is connected to the signal acquisition module 11 and is used to extract features based on the current and voltage monitoring values ​​to obtain oscillation frequency parameters and oscillation feature parameter values.

[0072] The feature extraction module 12 extracts current parameters based on current and voltage monitoring values, then calculates the algebraic difference between the current parameters and the system synchronization frequency reference value to obtain the oscillation frequency parameter, extracts voltage parameters, and calculates the maximum absolute value of the voltage parameter's deviation from the rated voltage within a preset time window as the oscillation amplitude parameter, generating oscillation characteristic parameter values. These oscillation characteristic parameter values ​​include: frequency difference parameters and amplitude deviation parameters.

[0073] In this embodiment, the feature extraction module 12 includes: a frequency extraction submodule 121, an amplitude extraction submodule 122, and a feature integration submodule 123.

[0074] The frequency extraction submodule 121 is used to extract the current parameter sequence based on the current and voltage monitoring values, calculate the algebraic difference between the current parameter sequence and the system synchronization frequency reference value, and generate oscillation frequency data.

[0075] Specifically, the current and voltage monitoring values ​​are used to extract the current parameter sequence, calculate the algebraic difference between the current parameter sequence and the system synchronization frequency reference value, and generate the oscillation frequency value.

[0076] For example, the frequency extraction submodule 121 calls the current and voltage monitoring values ​​to extract the current parameter sequence such as [1532.7, 1531.8, 1530.5] (unit A). The system synchronization frequency reference value is fixed at 50Hz. The actual frequency is calculated by zero-crossing detection: the time difference Δt (unit seconds) between adjacent zero-crossing points of the current sequence is recorded. The actual frequency = 1 / (2×Δt). For example, when Δt = 0.0102 seconds, the actual frequency = 1 / (2×0.0102) ≈ 49.02Hz. The algebraic difference = actual frequency - reference frequency = 49.02 - 50 = -0.98Hz. All differences are calculated within a 200ms window to form a sequence [-0.98, -1.05, -0.92]Hz, generating the oscillation frequency value.

[0077] The amplitude extraction submodule 122 is used to extract the voltage parameter sequence based on the current and voltage monitoring values, calculate the absolute value of the maximum deviation of the voltage parameter sequence relative to the rated voltage within a preset time window, and generate oscillation amplitude data.

[0078] For example, the amplitude extraction submodule 122 extracts the voltage parameter sequence [226.4, 225.8, 226.0] (unit kV) by calling the current and voltage monitoring values. The rated voltage is 220kV. The absolute value of the deviation at each point is calculated: |226.4-220|=6.4, |225.8-220|=5.8, |226.0-220|=6.0. Within a 200ms window, the maximum value of the deviation sequence [6.4, 5.8, 6.0] kV is taken (through comparison: 6.4>5.8→keep 6.4, 6.4<6.0→keep 6.4) to generate oscillation amplitude data.

[0079] The feature integration submodule 123 is used to integrate the oscillation frequency data and oscillation amplitude data into a set of parameter pairs to obtain oscillation feature parameter values.

[0080] For example, the feature integration submodule 123 calls the oscillation frequency value sequence [-0.98, -1.05] Hz and the oscillation amplitude data sequence [6.4, 5.8] kV, and pairs them by timestamp: time t1 (-0.98 Hz, 6.4 kV), time t2 (-1.05 Hz, 5.8 kV), generating a parameter pair set {(-0.98, 6.4), (-1.05, 5.8)}, and generating oscillation feature parameter values.

[0081] In one embodiment, the dynamic threshold module 13 is connected to the feature extraction module 12 and is used to acquire power grid load parameters and wind speed parameters. A dynamic threshold parameter value is generated by weighting the power grid load parameters and wind speed parameters. The dynamic threshold parameter value includes a load ratio value and a wind speed change rate value.

[0082] Specifically, the dynamic threshold module 13 obtains real-time grid load parameters through grid monitoring equipment, obtains real-time wind speed parameters through meteorological sensors, calculates the ratio of grid load parameters to preset benchmark load parameters to obtain the load ratio, calculates the difference between the current wind speed parameter and the wind speed parameter at the previous sampling time and divides it by the sampling time interval to obtain the wind speed change rate, and linearly superimposes the load ratio and the wind speed change rate according to preset weight coefficients to generate dynamic threshold parameter values.

[0083] In this embodiment, the dynamic threshold module 13 includes: a load parameter submodule 131, a wind speed change submodule 132, and a threshold synthesis submodule 133.

[0084] The load parameter submodule 131 is used to acquire power grid load parameters, detect load values ​​through power grid monitoring equipment, calculate the ratio result by algebraic division of the load value and the preset benchmark load value, and generate a load ratio value.

[0085] Specifically, the power grid load parameters are obtained, the load values ​​are detected by power grid monitoring equipment, and the ratio result is generated by algebraic division between the load value and the preset benchmark load value, thus generating the load ratio value.

[0086] For example, the load parameter submodule 131 acquires the grid load parameters. The grid monitoring equipment collects load values ​​in real time, such as 180 megawatts (MW). The preset reference load value is set to 170MW based on the wind farm's rated capacity of 200MW and a power factor of 0.85 (calculation basis: 200×0.85=170). An algebraic division operation is performed: load ratio value = current load value / reference load value = 180 / 170≈1.0588. In the example, when the load fluctuates to 185MW, the ratio = 185 / 170≈1.0882, and the load ratio value is generated.

[0087] The wind speed change submodule 132 is used to acquire wind speed parameters, collect wind speed value sequences through meteorological sensors, calculate the difference between the wind speed value at the current sampling point and the wind speed value at the previous sampling point, and then generate a rate of change result based on the difference and a preset sampling time interval (that is, divide by the preset sampling time interval to generate a rate of change result) to generate a wind speed change rate value.

[0088] Specifically, the wind speed change submodule 132 acquires wind speed parameters. The meteorological sensor collects the wind speed sequence [8.1, 8.3, 8.0] (unit: m / s) at a sampling rate of 4Hz. The preset sampling time interval Δt = 0.25 seconds (according to IEC 61400-12 standard) is used to calculate the rate of change, which is the difference between the current point and the previous point divided by Δt. For example, the rate of change for the second point = (8.3-8.1) / 0.25 = 0.8 m / s 2 The rate of change at the third point = (8.0 - 8.3) / 0.25 = -1.2 m / s 2 The generated sequence is [0.8, -1.2] m / s. 2 In the example, the data [7.9, 8.2, 7.8] within 10 seconds generates a rate of change [(8.2-7.9) / 0.25=1.2, (7.8-8.2) / 0.25=-1.6], which generates the wind speed rate of change value.

[0089] The threshold synthesis submodule 133 is used to perform linear multiplication of the load ratio value and the wind speed change rate value according to a preset weighting coefficient, and then perform addition to generate a synthesized value, and generate a dynamic threshold parameter value.

[0090] For example, the threshold synthesis submodule 133 calls the load ratio value of 1.0588 and the wind speed change rate value of 0.8 m / s. 2 The preset weighting coefficients are set based on power grid stability studies: load weight = 0.7 (because load has a greater impact on the threshold), wind speed weight = 0.3, and linear calculation is performed.

[0091] Load item = Load ratio value × Load weight = 1.0588 × 0.7 ≈ 0.7412;

[0092] Wind speed term = wind speed change rate × wind speed weight = 0.8 × 0.3 = 0.24 (unit normalization required: m / s) 2 Convert to a scalar, since the benchmark for the rate of change of wind speed is 1 m / s. 2 Corresponding to a 0.1 scale, therefore 0.8 m / s 2 →0.08);

[0093] Composite value = Load term + Wind speed term = 0.7412 + 0.08 = 0.8212;

[0094] In this embodiment, the load ratio is 1.0882 and the wind speed change rate is -1.2 m / s. 2 When the scale is -0.12, the synthesized value is 1.0882×0.7+(-0.12)×0.3≈0.7617-0.036=0.7257, generating the dynamic threshold parameter value.

[0095] Please continue reading. Figures 2 to 4 .

[0096] In one embodiment, the state judgment module 14 is connected to the dynamic threshold module 13, and is used to determine whether the oscillation frequency parameter is greater than a zero threshold based on the oscillation frequency parameter and the dynamic threshold, and to perform state logic judgment according to the judgment conditions to obtain an oscillation state judgment value. Specifically, the oscillation state judgment value refers to an oscillation risk indicator.

[0097] Specifically, the state judgment module 14 extracts the oscillation frequency and amplitude parameters by calling the oscillation characteristic parameter values, calls the dynamic threshold parameter value, performs an algebraic subtraction operation between the oscillation frequency parameter value and the dynamic threshold parameter value to obtain the frequency deviation value, determines whether the frequency deviation value is greater than zero, and generates an oscillation state judgment value. This module focuses on the state judgment stage of the wind power subsynchronous oscillation monitoring system by directly calling the oscillation frequency parameter value and the dynamic threshold parameter value to perform an algebraic subtraction operation, performs binary logic judgment based on the zero reference point, and uses real-time acquired data as input to ensure a closed-loop process.

[0098] In this embodiment, the state determination module 14 includes: a feature parameter extraction submodule 141, a comparison operation submodule 142, and a state determination submodule 143.

[0099] The feature parameter extraction submodule 141 is used to extract the oscillation frequency parameter and the oscillation amplitude parameter based on the oscillation feature parameter value, integrate the oscillation frequency parameter and the oscillation amplitude parameter into a parameter pair set, and generate frequency amplitude pair values.

[0100] For example, calling the oscillation characteristic parameter values, which are parameter pairs such as {(-0.98, 6.4), (-1.05, 5.8)} (units Hz and kV), the oscillation frequency parameter is extracted by accessing the first element of each tuple in the set. For example, the first tuple takes -0.98Hz, the second tuple takes -1.05Hz, forming a frequency sequence [-0.98, -1.05]Hz. The oscillation amplitude parameter is extracted by accessing the second element of each tuple. For example, the first tuple takes 6.4kV, the second tuple takes 5.8kV, forming an amplitude sequence [6.4, 5.8]kV. The merging process pairs frequencies and amplitudes according to the same index position. The index is based on the timestamp order. For example, at time t1, (-0.98Hz, 6.4kV) is paired, and at time t2, (-1.05Hz, 5.8kV) is paired, generating a new set {(-0.98, 6.4), (-1.05, 5.8)}. In the example, when (-0.92, 6.0) is added to the input set, the output expands to {(-0.98, 6.4), (-1.05, 5.8), (-0.92, 6.0)}. There is no additional calculation or filtering; the parameter pair list is directly output, generating frequency and amplitude pairs.

[0101] The comparison operation submodule 142 is used to extract the oscillation frequency parameter based on the frequency amplitude pair value, call the dynamic threshold parameter value, and perform data calculation based on the oscillation frequency parameter and the dynamic threshold parameter value to obtain the difference result, thereby generating a frequency difference value.

[0102] Specifically, the data calculation in this module refers to the process of performing an algebraic subtraction operation by subtracting the dynamic threshold parameter from the oscillation frequency parameter to generate the difference result.

[0103] For example, the comparison operation submodule 142 calls frequency amplitude pairs such as {(-0.98, 6.4), (-1.05, 5.8)} to extract the oscillation frequency parameter by reading the frequency part of each tuple. For example, the first group takes -0.98Hz, and the second group takes -1.05Hz, forming a sequence [-0.98, -1.05]Hz. It calls the dynamic threshold parameter value such as 0.7257 (from the threshold synthesis module output) and performs an algebraic subtraction operation: subtracting the dynamic threshold parameter value from the current frequency value to generate the difference result. For example, the first group calculates -0.98 - 0.7257 = -1.7057, and the second group calculates -1.05 - 0.7257 = -1.7757, forming a sequence [-1.7057, -1.7757]Hz. In the example, when the dynamic threshold is updated to 0.8 and the frequency is -1.0Hz, the difference = -1.0 - 0.8 = -1.8Hz, generating a frequency difference value.

[0104] The state determination submodule 143 is used to determine whether the frequency difference value is greater than a zero threshold based on the frequency difference value, generate a logical judgment result, and generate an oscillation state determination value.

[0105] Specifically, the frequency difference value is called as a sequence [-1.7057, -1.7757] Hz, and the zero threshold is fixed at 0 (according to the IEC 60255-24 standard subsynchronous oscillation judgment benchmark). The judgment process is a point-by-point comparison: if the current difference value > 0, the logic true (1) is output, otherwise the logic false (0) is output. For example, the first point -1.7057 < 0 generates 0, the second point -1.7757 < 0 generates 0, forming the sequence [0,0]. In the example, when the difference value is 0.5 Hz (> 0), 1 is output, generating the oscillation state judgment value.

[0106] Please continue reading. Figure 2 and Figure 3 .

[0107] In one embodiment, the result output module 15 is connected to the state judgment module 14, and is used to generate an indication signal based on the oscillation state judgment value, and transmit the indication signal to the protection device interface to generate a monitoring alarm signal value, so as to realize the subsynchronous oscillation monitoring of the wind power generation system. Specifically, when the oscillation state judgment value is true, the signal is set to a high level; when the oscillation state judgment value is false, the signal is set to a high level.

[0108] Specifically, the oscillation state determination value is invoked. When the oscillation state determination value is true, an alarm signal is generated; when the oscillation state determination value is false, a normal signal is generated. The signal is then transmitted to the protection device coordination interface to generate a monitoring alarm signal value. This monitoring alarm signal value includes either an alarm signal state or a normal signal state.

[0109] In this embodiment, the result output module 15 includes: a status generation submodule 151, a transmission execution submodule 152, and an alarm output submodule 153.

[0110] The state generation submodule 151 is used to obtain a logic signal value based on the oscillation state determination value, and to make a judgment based on the logic signal value to obtain a state signal value.

[0111] Specifically, the oscillation state determination value is called, and a logic signal value is generated based on this value. When the oscillation state determination value is true, the signal is set to a high level, and when the oscillation state determination value is false, the signal is set to a low level, thus generating a state signal value.

[0112] For example, the oscillation state determination value is a logical sequence such as [1,0] (1 is true, 0 is false). The level setting rule is: true corresponds to 5V high level, false corresponds to 0V low level. According to the IEC 61131-2 standard digital signal specification, the signal conversion is performed: traverse the determination value sequence, output 5V when the value is 1, and output 0V when the value is 0. For example, the input sequence [1,0,1] is converted to [5,0,5]V. In the example, when the determination value is updated to [0,1], [0,5]V is output, generating the state signal value.

[0113] The transmission execution submodule 152 is used to transmit the status signal value to the protection device coordination interface through the optical fiber interface, generate a transmission confirmation flag after the signal transmission is completed, and obtain the transmission completion value.

[0114] For example, the transmission execution submodule 152 calls the status signal value, such as [5,0]V. The fiber optic interface uses a transmission rate of 100Mbps, and the protocol conforms to the IEC 61850-9-2 standard. The transmission process is as follows: the voltage value is encoded into a 16-bit binary number (5V→0000010100000000, 0V→00000000000000000), and sent through the fiber optic cable to the protection device coordination interface MAC address 00-1B-63-84-45-E6. The receiving end returns a CRC check code. After the sending end verifies that the check code matches, it generates a transmission confirmation flag (success = 1, failure = 0). In this example, when the transmission of [5,0]V passes the reception verification, the flag = 1, and a transmission completion value is generated.

[0115] The alarm output submodule 153 is used to obtain the monitoring alarm signal value based on the transmission completion value and generate the monitoring alarm signal value.

[0116] Specifically, the transmission completion value is invoked to generate a monitoring alarm signal value.

[0117] The alarm output submodule 153 calls the transmission completion value as a sequence [1,1]. The alarm generation rule is: when the transmission completion value is 1, the alarm signal value 1 (activated) is output, and when it is 0, the alarm signal value 0 (inactive) is output. There is no intermediate calculation process. In the example, when [1,0] is input, [1,0] is output, and the monitoring alarm signal value is generated.

[0118] The system also includes: after generating a monitoring alarm signal value, triggering the protection device to perform a circuit breaker tripping action, simultaneously starting the data recording unit to store the parameters of the entire oscillation event, sending an alarm notification to the central monitoring system, and generating an event analysis report for operation and maintenance personnel to access.

[0119] For example, after generating a monitoring alarm signal value, the circuit breaker is triggered to trip, and a 24V pulse signal is output to the circuit breaker control coil via hardwiring. The pulse width is set to 200ms (according to GB / T). According to the 1980 Circuit Breaker Response Standard, in this example, when the alarm signal value = 1, a pulse signal is output to drive the A-phase circuit breaker tripping mechanism. Simultaneously, the data recording unit is activated, calling up the full-process parameters of the oscillation event: the current and voltage monitoring value sequence within the time window (e.g., current [1532.7, 1531.8] A, voltage [226.4, 225.8] kV), the oscillation characteristic parameter value sequence (e.g., {(-0.98, 6.4), (-1.05, 5.8)}), and the dynamic threshold parameter value sequence (e.g., [0.7257, 0.7289]). These are stored in binary format in non-volatile memory at addresses 0x8000-0xFFFF, with a storage rate of 10 MB / s. In this example, the event duration is 1.2 seconds, and the stored data size is 12 MB. An alarm notification is sent to the central monitoring system via the IEC 60870-5-104 protocol, targeting IP. 192.168.1.100, Alarm Information Encoding: Event Type Code = 0x0A (Subsynchronous Oscillation), Timestamp = 20250731_142030, Severity Level = 1 (Emergency), Generate Event Analysis Report by calling stored parameter data. The report template includes an event summary table: Maximum Oscillation Frequency = -1.05Hz (Time 142030_0150), Maximum Oscillation Amplitude = 6.4kV (Time 142030_0149), Circuit Breaker Action Delay = 85ms (Time from issuance of tripping command to completion), Report Storage Path: / reports / 20250731_142030.pdf. In this example, when the oscillation lasts for 3 seconds, the report page count is 8 pages. Generate Event Analysis Report.

[0120] In summary, the subsynchronous oscillation monitoring system for wind power generation systems described in this application responds to load fluctuations and wind speed changes in real time through a dynamic threshold mechanism, eliminating the rigidity problem of fixed thresholds. Algebraic difference calculation avoids feature ambiguity, time window extreme value extraction improves feature recognition accuracy, and timestamp alignment eliminates data offset errors. This significantly reduces the probability of misjudgment under complex operating conditions, enhances monitoring sensitivity and protection accuracy, and ensures stable operation of the power grid.

[0121] It should be noted that the division of the various modules in the above system is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can be implemented entirely in software through processing element calls; they can be fully implemented in hardware; or some modules can be implemented by processing element calls to software, while others are implemented in hardware. For example, module x can be a separate processing element, or it can be integrated into a chip within the system. Alternatively, it can be stored as program code in the system's memory, and its function can be called and executed by a processing element. The implementation of other modules is similar. Moreover, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element mentioned here can be an integrated circuit with signal processing capabilities. During implementation, each step of the above method or each of the above modules can be completed through integrated logic circuits in the hardware of the processor element or through software instructions.

[0122] Please see Figure 5 The diagram shows a schematic overall flow chart of the subsynchronous oscillation monitoring method for wind power generation systems described in this application, as illustrated in one embodiment. Figure 5 As shown, this embodiment provides a method for monitoring subsynchronous oscillations in a wind power generation system. The method includes the following steps:

[0123] S1, obtain the output current parameters and grid interface voltage parameters of the target wind farm, as well as the grid load parameters and wind speed parameters.

[0124] Specifically, acquiring key parameters such as the output current of the target wind farm, grid interface voltage, grid load, and wind speed typically relies on a Supervisory Control and Data Acquisition (SCADA) system as the core technology. This system collects massive amounts of data in real time through intelligent sensors, power quality analyzers, and weather stations deployed at wind turbines, substations, and grid interfaces, and transmits the data to a central monitoring platform for centralized processing, display, and storage, providing data support for the intelligent control and efficient operation of the wind farm.

[0125] S2, based on the output current parameters and the grid interface voltage parameters, data processing is performed to obtain current and voltage monitoring values; wherein, the current and voltage monitoring values ​​of the signal acquisition module are specifically the instantaneous current value and the instantaneous voltage value.

[0126] Please see Figure 6 The diagrams shown are schematic S2 of one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application. Figure 6 As shown, step S2 includes the following steps:

[0127] S21, Obtain the output current parameters of the wind farm, collect the instantaneous current value in real time through the current sensor, record the sampling timestamp and current value sequence, and generate the current sampling value;

[0128] S22, acquire grid interface voltage parameters, collect instantaneous voltage values ​​in real time through voltage monitoring device, record sampling timestamps and voltage value sequences, and generate voltage acquisition values;

[0129] S23, based on the current sampling value and voltage acquisition value, align the current value sequence and voltage value sequence with the same timestamp, integrate them into a time-synchronized current and voltage data pair set, and generate current and voltage monitoring values.

[0130] Specifically, the output current parameters of the wind farm are collected in real time by a current sensor, and the voltage parameters of the grid interface are collected in real time by a voltage monitoring device. The current parameters and voltage parameters are aligned according to the time series and integrated into a set of current and voltage data pairs with the same timestamp to generate current and voltage monitoring values.

[0131] S3, based on the current and voltage monitoring values, feature extraction is performed to obtain oscillation feature parameter values; wherein, the oscillation feature parameter values ​​include frequency difference parameters and amplitude deviation parameters.

[0132] Please see Figure 7 The diagram shown is a schematic S3 diagram of the subsynchronous oscillation monitoring method for wind power generation systems described in this application embodiment. Figure 7 As shown, step S3 includes the following steps:

[0133] S31, extract the current parameter sequence based on the current and voltage monitoring values, calculate the algebraic difference between the current parameter sequence and the system synchronization frequency reference value, and generate the oscillation frequency value;

[0134] S32, Based on the current and voltage monitoring values, extract the voltage parameter sequence, calculate the maximum absolute value of the voltage parameter sequence relative to the rated voltage within a preset time window, and generate the oscillation amplitude value;

[0135] S33, based on the oscillation frequency value and the oscillation amplitude value, integrate the oscillation frequency value and the oscillation amplitude value into a set of parameter pairs to generate oscillation characteristic parameter values.

[0136] Specifically, based on the current and voltage monitoring values, current parameters are extracted, the algebraic difference between the current parameters and the system synchronization frequency reference value is calculated to obtain the oscillation frequency parameter, voltage parameters are extracted, and the maximum absolute value of the deviation of the voltage parameters from the rated voltage within a preset time window is calculated as the oscillation amplitude parameter, thereby generating oscillation characteristic parameter values.

[0137] S4. Obtain dynamic threshold parameter values ​​based on the power grid load parameters and wind speed parameters; wherein, the dynamic threshold parameter values ​​mainly include parameters such as load ratio value and wind speed change rate value.

[0138] Please see Figure 8 The diagram shows the S4 flow chart of the subsynchronous oscillation monitoring method for wind power generation systems described in this application embodiment. Figure 8 As shown, step S4 includes the following steps:

[0139] S41, Obtain power grid load parameters, detect load values ​​through power grid monitoring equipment, calculate the ratio result by algebraic division of the load value and the preset benchmark load value, and generate a load ratio value.

[0140] S42, acquire wind speed parameters, collect wind speed value sequence through meteorological sensors, calculate the difference between the wind speed value at the current sampling point and the wind speed value at the previous sampling point, and then divide it by the preset sampling time interval to generate the rate of change result, and generate the wind speed rate of change value.

[0141] S43, based on the load ratio value and the wind speed change rate value, perform a linear multiplication operation on the load ratio value and the wind speed change rate value according to a preset weighting coefficient, and then perform an addition operation to generate a composite value, thereby generating a dynamic threshold parameter value.

[0142] Specifically, real-time grid load parameters are obtained through grid monitoring equipment, real-time wind speed parameters are obtained through meteorological sensors, the load ratio is obtained by calculating the ratio of grid load parameters to preset benchmark load parameters, the wind speed change rate is obtained by calculating the difference between the current wind speed parameter and the wind speed parameter at the previous sampling time and dividing it by the sampling time interval, and the load ratio and wind speed change rate are linearly superimposed according to preset weighting coefficients to generate dynamic threshold parameter values.

[0143] S5, based on the oscillation frequency parameter in the oscillation characteristic parameter value, a state judgment is made to obtain an oscillation state judgment value; wherein, the oscillation state judgment value includes oscillation risk indicators, etc.

[0144] Please see Figure 9 The diagram shows a flowchart of step S5 in one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application. Figure 9 As shown, step S5 includes the following steps:

[0145] S51, based on the oscillation characteristic parameter values, extract the oscillation frequency parameter, extract the oscillation amplitude parameter, integrate the oscillation frequency parameter and the oscillation amplitude parameter into a parameter pair set, and generate frequency amplitude pair values;

[0146] S52, based on the frequency amplitude pair value, extract the oscillation frequency parameter, call the dynamic threshold parameter value, perform an algebraic subtraction operation between the oscillation frequency parameter and the dynamic threshold parameter value to generate a difference result, and generate a frequency difference value;

[0147] S53, based on the frequency difference value, determine whether the frequency difference value is greater than the zero threshold to generate a logical judgment result and generate an oscillation state judgment value.

[0148] Specifically, based on the oscillation characteristic parameter values, the oscillation frequency parameter and oscillation amplitude parameter are extracted. The dynamic threshold parameter value is called, and the oscillation frequency parameter and the dynamic threshold parameter value are subjected to algebraic subtraction to obtain the frequency deviation value. It is then determined whether the frequency deviation value is greater than zero, and an oscillation state judgment value is generated. This module is for the state judgment link of the wind power subsynchronous oscillation monitoring system. The key technical means is to directly call the oscillation frequency parameter and the dynamic threshold parameter value to perform algebraic subtraction, and perform binary logic judgment based on the zero reference point. The participating items are derived from real-time acquired data to ensure a closed-loop process.

[0149] S6, obtain the monitoring alarm signal value based on the oscillation state determination value. Specifically, the monitoring alarm signal value is either an alarm signal state or a normal signal state.

[0150] Please see Figure 10 The flowchart of S6 in one embodiment of the subsynchronous oscillation monitoring method for wind power generation systems described in this application is shown. Figure 10 As shown, step S6 includes the following steps:

[0151] S61, based on the oscillation state determination value, generate a logic signal value based on the value. When the oscillation state determination value is true, set the signal to a high level; when the oscillation state determination value is false, set the signal to a low level, and generate a state signal value.

[0152] S62, based on the status signal value, transmit the value to the protection device coordination interface through the optical fiber interface, confirm the completion of signal transmission, generate a transmission confirmation flag, and generate a transmission completion value;

[0153] S63, Based on the transmission completion value, generate a monitoring alarm signal value.

[0154] Specifically, based on the oscillation state determination value, an alarm signal is generated when the oscillation state determination value is true, and a normal signal is generated when the oscillation state determination value is false. The signal is then transmitted to the protection device coordination interface to generate a monitoring alarm signal value.

[0155] As described above, the subsynchronous oscillation monitoring method for wind power generation systems described in this application collects current and voltage data in real time with timestamp alignment to form monitoring values; generates oscillation frequency parameters based on algebraic differences; extracts the maximum deviation of the voltage sequence relative to the rated value to generate oscillation amplitude parameters; then integrates the load ratio and wind speed change rate to calculate a dynamic threshold; performs a direct algebraic comparison between the oscillation frequency and the dynamic threshold and determines whether the deviation value is greater than the zero threshold to generate a logic state; and outputs an alarm signal to the protection device.

[0156] In summary, the subsynchronous oscillation monitoring system and method for wind power generation systems provided in this application have the following beneficial effects:

[0157] The subsynchronous oscillation monitoring system for wind power generation systems provided in this application can synchronously collect current and voltage data to form a time-aligned set, eliminate signal transmission delay errors, improve data integrity, calculate the real-time algebraic difference between the current sequence and the system frequency to directly reflect frequency offset characteristics, avoid feature ambiguity caused by traditional averaging, identify the maximum fluctuation amplitude of the voltage sequence relative to the rated value within a specific time window, focus on key anomalies, replace wide-range analysis, improve feature extraction accuracy, dynamically fuse load ratio and wind speed change rate, generate adaptive thresholds based on actual impact ratios, match changes in operating conditions in real time, perform direct algebraic comparisons between frequency parameters and dynamic thresholds, determine whether the deviation exceeds the zero reference, output clear logical status, and ensure a transparent and verifiable process. The overall processing logic combines dynamic environmental response and accurate feature extraction to enhance monitoring sensitivity and reliability, reduce the probability of misjudgment caused by external interference, optimize the accuracy of protection actions, and ensure stable operation of the power grid.

[0158] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0159] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A subsynchronous oscillation monitoring system for wind power generation systems, characterized in that, The system includes: a signal acquisition module, a feature extraction module, a dynamic threshold module, a state judgment module, and a result output module; The signal acquisition module is used to acquire the output current parameters and grid interface voltage parameters within the target wind farm area, and integrate the output current parameters and grid interface voltage parameters to generate current and voltage monitoring values; the current and voltage monitoring values ​​include instantaneous current values ​​and instantaneous voltage values; The feature extraction module is connected to the signal acquisition module and is used to perform feature extraction based on the current and voltage monitoring values ​​to obtain oscillation frequency parameters and oscillation characteristic parameter values. The dynamic threshold module is connected to the feature extraction module and is used to obtain power grid load parameters and wind speed parameters. By performing weighted calculations on the power grid load parameters and wind speed parameters, dynamic threshold parameter values ​​are generated. The state judgment module is connected to the dynamic threshold module and is used to determine whether the oscillation frequency parameter is greater than the zero threshold based on the oscillation frequency parameter and the dynamic threshold, and to perform state logic judgment according to the judgment conditions to obtain the oscillation state judgment value. The result output module is connected to the state judgment module and is used to generate an indication signal based on the oscillation state judgment value, and transmit the indication signal to the protection device interface to generate a monitoring alarm signal value, so as to realize the subsynchronous oscillation monitoring of the wind power generation system.

2. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The signal acquisition module includes: a current acquisition submodule, a voltage acquisition submodule, and a data integration submodule; The current acquisition submodule is used to acquire the output current parameters of the wind farm, collect instantaneous current values ​​in real time through a current sensor, record the sampling timestamp and current value sequence, and generate current sampling values. The voltage acquisition submodule is used to acquire grid interface voltage parameters, collect instantaneous voltage values ​​in real time through a voltage monitoring device, record sampling timestamps and voltage value sequences, and generate voltage acquisition values. The data integration submodule is used to align the current value sequence and voltage value sequence with the same timestamp based on the current sampling value and voltage acquisition value, integrate them into a time-synchronized current and voltage data pair set, and generate current and voltage monitoring values.

3. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The feature extraction module includes: a frequency extraction submodule, an amplitude extraction submodule, and a feature integration submodule; The frequency extraction submodule is used to extract a current parameter sequence based on the current and voltage monitoring values, calculate the algebraic difference between the current parameter sequence and the system synchronization frequency reference value, and generate oscillation frequency data. The amplitude extraction submodule is used to extract a voltage parameter sequence based on the current and voltage monitoring values, calculate the absolute value of the maximum deviation of the voltage parameter sequence relative to the rated voltage within a preset time window, and generate oscillation amplitude data. The feature integration submodule is used to integrate the oscillation frequency data and oscillation amplitude data into a set of parameter pairs, thereby obtaining oscillation feature parameter values.

4. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The dynamic threshold module includes: a load parameter submodule, a wind speed change submodule, and a threshold synthesis submodule; The load parameter submodule is used to acquire power grid load parameters, detect load values ​​through power grid monitoring equipment, calculate the ratio result by algebraic division of the load value and the preset benchmark load value, and generate a load ratio value. The wind speed change submodule is used to acquire wind speed parameters, collect wind speed value sequences through meteorological sensors, calculate the difference between the wind speed value at the current sampling point and the wind speed value at the previous sampling point, and then generate a rate of change result based on the difference and a preset sampling time interval, thereby generating a wind speed change rate value. The threshold synthesis submodule is used to perform linear multiplication of the load ratio value and the wind speed change rate value according to a preset weighting coefficient, and then perform addition to generate a synthesized value, thereby generating a dynamic threshold parameter value.

5. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The state determination module includes: a feature parameter extraction submodule, a comparison operation submodule, and a state determination submodule; The feature parameter extraction submodule is used to extract the oscillation frequency parameter and the oscillation amplitude parameter based on the oscillation feature parameter value, and integrate the oscillation frequency parameter and the oscillation amplitude parameter into a parameter pair set to generate frequency amplitude pair values; The comparison operation submodule is used to extract the oscillation frequency parameter based on the frequency amplitude pair value, call the dynamic threshold parameter value, and perform data calculation based on the oscillation frequency parameter and the dynamic threshold parameter value to obtain the difference result, thereby generating a frequency difference value. The state determination submodule is used to determine whether the frequency difference value is greater than a zero threshold based on the frequency difference value, generate a logical judgment result, and generate an oscillation state determination value.

6. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The result output module includes: a status generation submodule, a transmission execution submodule, and an alarm output submodule; The state generation submodule is used to obtain a logic signal value based on the oscillation state determination value, and to make a judgment based on the logic signal value to obtain a state signal value. The transmission execution submodule is used to transmit the status signal value to the protection device coordination interface through the optical fiber interface, generate a transmission confirmation flag after the signal transmission is completed, and obtain the transmission completion value. The alarm output submodule is used to obtain the monitoring alarm signal value based on the transmission completion value and generate the monitoring alarm signal value.

7. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 6, characterized in that, Also includes: When the oscillation state determination value is true, the signal is set to a high level; when the oscillation state determination value is false, the signal is set to a high level.

8. The subsynchronous oscillation monitoring system for wind power generation systems according to claim 1, characterized in that, The system also includes: Based on the monitoring alarm signal value, the protection device is triggered to perform the circuit breaker tripping action, and the data recording unit is simultaneously started to store the parameters of the entire oscillation event, send alarm notification to the central monitoring system, and generate an event analysis report for operation and maintenance personnel to use.

9. A method for monitoring subsynchronous oscillations in a wind power generation system, characterized in that, The method includes: Obtain the output current parameters and grid interface voltage parameters of the target wind farm, as well as the grid load parameters and wind speed parameters; Data processing is performed based on the output current parameters and the grid interface voltage parameters to obtain current and voltage monitoring values; Based on the current and voltage monitoring values, feature extraction is performed to obtain oscillation characteristic parameter values; The dynamic threshold parameter value is obtained based on the power grid load parameter and wind speed parameter; Based on the oscillation frequency parameter in the oscillation characteristic parameter value, the state is determined to obtain the oscillation state determination value; The monitoring alarm signal value is obtained based on the oscillation state determination value.

10. The method for monitoring subsynchronous oscillations in a wind power generation system according to claim 9, characterized in that, Based on the oscillation frequency parameter among the oscillation characteristic parameter values, the oscillation state determination value is obtained, including: The oscillation frequency parameter is extracted based on the oscillation characteristic parameter value; The oscillation frequency parameters are integrated to obtain frequency amplitude values; The oscillation frequency parameter is extracted based on the frequency amplitude logarithm. The frequency difference value is obtained by calculating the difference between the dynamic threshold parameter value and the oscillation frequency parameter. Logical judgment is performed based on the frequency difference value, and a logical judgment result is generated to obtain the oscillation state determination value.

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