Unified monitoring method and system for broadband oscillation dynamic identification and tracing

Abstract

This invention belongs to the field of power system monitoring technology, specifically disclosing a unified monitoring method and system for dynamic identification and source tracing of broadband oscillations. The method includes: acquiring current and voltage data from power system monitoring nodes and separating harmonic current components; calculating dispersed and generated currents at harmonic frequencies, and merging the dispersed and generated currents into a deviation current; using an adaptive envelope deviation criterion for preliminary oscillation early warning; extracting a segment of deviation current data after the criterion response and performing spectral analysis to determine whether abnormal frequency components exist in the deviation current; if so, determining that the system is affected by oscillations; performing frequency domain decomposition on the voltage and deviation current of the monitoring nodes and calculating the deviation power spectral density in the frequency domain; and determining the oscillation frequency and locating the oscillation source based on the deviation power spectral density. This invention achieves accurate location based on measurement data, greatly reducing the dependence on the real-time performance of network-wide parameters.

Description

Technical Field

[0001] This invention relates to the field of power system monitoring technology, and in particular to a unified monitoring method and system for dynamic identification and source tracing of broadband oscillations. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the large-scale penetration of power electronics and renewable energy through converter interfaces, modern power systems are undergoing a profound transformation from high rotational inertia to low inertia and weak damping characteristics. This transformation significantly weakens the system's stability margin, leading to a sharp increase in the risk of cross-regional low-frequency oscillations and broadband oscillations. If oscillations are not identified and accurately located in a timely manner, the resulting chain reaction may jeopardize the safe operation of the entire synchronous grid and even cause large-scale power outages. Therefore, developing efficient and real-time oscillation source location tools has become a critical issue that urgently needs to be addressed in the field of power system operation and control.

[0004] The widespread deployment of synchronous phasor measurement units provides abundant data support for monitoring system dynamics. However, existing oscillation analyses largely rely on phasor representations, which have inherent limitations in capturing non-stationary processes and handling beat frequency phenomena caused by interharmonics. Most existing solutions often face bottlenecks in handling in-process analysis due to high model dependence or poor real-time computation.

[0005] Current methods for oscillation source localization are mainly divided into two categories: model-driven and data-driven. Modal analysis, represented by eigenvalue analysis, while theoretically mature, heavily relies on accurate linearized state equations. In IBR systems containing numerous black-box models, real-time acquisition of system parameters is extremely challenging, limiting its application to pre-assessment. Dissipative energy methods determine source location by monitoring energy flow direction, with clear physical meaning. However, this method is based on heuristic formulas and heavily relies on phasor power calculations from the PMU, making it susceptible to power spurious oscillations caused by phasor aliasing and interharmonics.

[0006] In recent years, data-driven methods such as dynamic mode decomposition have demonstrated strong modality recognition capabilities. However, due to their lack of deep mapping of physical mechanisms, they are unable to analyze the causal logic of energy exchange, and thus cannot support subsequent control and governance. Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes a unified monitoring method and system for dynamic identification and source tracing of broadband oscillations. This method extends steady-state power decomposition to real-time power decomposition in the time domain, and the power decomposition is applied only to harmonics. After determining the occurrence of oscillations through current decomposition, the specific oscillation source is identified by screening for obvious negative peaks in the power spectral density, and the location of the oscillation source is determined by the sign of the power spectral density and the relevant reference direction.

[0008] In some implementations, the following technical solutions are adopted: A unified monitoring method for dynamic identification and source tracing of broadband oscillations includes: Acquire current and voltage data from power system monitoring nodes and separate out harmonic current components; Calculate the dispersed current and the generated current at the harmonic frequency, and combine the dispersed current and the generated current into a deviation current; Based on the aforementioned deviation current, an initial oscillation warning is provided using an adaptive envelope deviation criterion. In response to the occurrence of the initial oscillation warning, a segment of deviation current data after the criterion response is extracted and subjected to spectrum analysis to determine whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation. The voltage and deviation current of the monitoring node are decomposed in the frequency domain to calculate the deviation power spectral density in the frequency domain; the extreme points in the deviation power spectral density where the amplitude exceeds the preset multiple of the background noise are determined, and their corresponding frequencies are extracted as the oscillation frequencies; the oscillation source is located according to the positive and negative values ​​of the deviation power spectral density.

[0009] As a further approach, the deviation between the harmonic impedance and the equivalent impedance at each harmonic frequency is defined as the dispersed current, the harmonic current at the power generation frequency is defined as the generating current, and the sum of the two is defined as the deviation current.

[0010] As a further approach, an adaptive envelope bias criterion is used for preliminary oscillation early warning, specifically: Calculate the real-time envelope and average envelope of the deviation current respectively. If the real-time envelope is greater than the tolerance range of the average envelope, the system is judged to have started to oscillate and an early warning is issued.

[0011] As a further approach, a segment of the deviation current data following the criterion response is extracted and subjected to spectrum analysis to determine whether there are abnormal frequency components in the deviation current. Specifically: After the criterion response, the deviation current data of the predetermined cycle is extracted and decomposed by FFT to determine the frequencies corresponding to multiple amplitude peaks. If the ratio of the frequency corresponding to at least one amplitude peak to the fundamental frequency is not an integer, that is, there is an abnormal frequency component, then the system is determined to have an oscillation fault.

[0012] As a further approach, the voltage and deviation current of the monitoring node are decomposed in the frequency domain, and the deviation power spectral density in the frequency domain is calculated, specifically: The complex deviation power spectrum is calculated based on the complex conjugate product of the frequency domain voltage and the frequency domain deviation current of the monitoring node. The real part of the complex deviation power spectrum is the deviation power spectral density.

[0013] As a further approach, the oscillation source is located based on the positive or negative value of the deviation power spectral density, specifically: If the deviation power spectral density value of the monitoring node is greater than zero, then the monitoring node is an energy-consuming node; if the deviation power spectral density value of the monitoring node is less than zero, then the monitoring node is an energy-generating node.

[0014] As a further approach, all nodes that trigger preliminary oscillation warnings are defined as affected monitoring nodes; the deviation power spectral density values ​​of all affected monitoring nodes are sorted, and these values ​​are used as feature weights to map onto the power grid spatial topology to construct a deviation power flow graph characterizing the direction of oscillation energy transmission; based on the path of energy propagation from diverging nodes to dissipating nodes in the deviation power flow graph, the energy divergence starting point is traced and locked as a wide-area oscillation source.

[0015] In other embodiments, the following technical solutions are adopted: A unified monitoring system for dynamic identification and source tracing of broadband oscillations includes: The data acquisition module is used to acquire current and voltage data of power system monitoring nodes and separate out harmonic current components; The transient power calculation module is used to calculate the dispersed current and generated current at each harmonic frequency, and to combine the dispersed current and generated current into a deviation current. The preliminary oscillation early warning module is used to perform preliminary oscillation early warning based on the deviation current and using an adaptive envelope deviation criterion. The oscillation identification module is used to respond to the occurrence of the initial oscillation warning by intercepting a segment of deviation current data after the criterion response, performing spectrum analysis, and determining whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation. The oscillation source location module is used to perform frequency domain decomposition on the voltage and deviation current of the monitoring node, calculate the deviation power spectral density in the frequency domain, determine the extreme point in the deviation power spectral density where the amplitude exceeds the preset multiple of the background noise, extract the corresponding frequency as the oscillation frequency, and locate the oscillation source according to the positive and negative values ​​of the deviation power spectral density.

[0016] In other embodiments, the following technical solutions are adopted: A terminal device includes a processor and a memory, the processor being used to implement instructions; the memory being used to store multiple instructions adapted to be loaded and executed by the processor for the aforementioned unified monitoring method for broadband oscillation dynamic identification and tracing.

[0017] In other embodiments, the following technical solutions are adopted: A computer-readable storage medium storing a plurality of instructions adapted to be loaded and executed by a processor of a terminal device, the aforementioned unified monitoring method for broadband oscillation dynamic identification and tracing.

[0018] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention constructs an instantaneous power decomposition framework, which orthogonally decomposes the complex time-domain current waveform into physical components that reflect the essential characteristics of the system, thus overcoming the frequency aliasing problem of the traditional phasor power analysis method under non-stationary oscillation conditions.

[0019] (2) By analyzing the coupling of deviation current, this invention separates the oscillation characteristics from the complex fundamental background and random interference, clarifies the physical nature of the interharmonic component as the cause of oscillation, and significantly improves the timeliness of identifying complex disturbances.

[0020] (3) The present invention introduces a time-domain early warning and a preliminary judgment mechanism combined with frequency domain confirmation. It performs lightweight preliminary identification through adaptive envelope deviation criteria and initiates complex spectrum analysis only when the early warning is triggered. This not only overcomes the problem of computing power redundancy caused by continuous high-frequency monitoring throughout the day, but also effectively filters out false alarms caused by normal transient impacts of the power grid, thus achieving a balance between high monitoring efficiency and high accuracy.

[0021] (4) Based on node voltage and deviation current, the present invention calculates deviation power spectral density, and then determines oscillation frequency and oscillation source location, realizing accurate positioning based on measurement data, which greatly reduces the dependence on the real-time performance of network parameters.

[0022] Other features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] Figure 1 This is a flowchart of a unified monitoring method for dynamic identification and source tracing of broadband oscillations in an embodiment of the present invention; Figure 2 This is a measured voltage waveform diagram of the PCC point provided in an embodiment of the present invention; Figure 3 This is a measured current waveform diagram of the PCC point provided in an embodiment of the present invention; Figure 4This is an instantaneous decomposition diagram of harmonic active current, reactive current, deviation current, and fundamental current obtained after S-transformation in an embodiment of the present invention. Figure 5 This is an adaptive envelope monitoring diagram based on deviation current in an embodiment of the present invention; Figure 6 This is a schematic diagram of abnormal frequency component identification based on spectral decomposition in an embodiment of the present invention; Figure 7 This is a schematic diagram of oscillation source localization based on deviation power spectral density in an embodiment of the present invention. Detailed Implementation

[0024] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Example 1 In one or more embodiments, a unified monitoring method for dynamic identification and source tracing of broadband oscillations is disclosed, combining... Figure 1 Specifically, it includes the following processes: S101: Acquire current and voltage data of power system monitoring nodes and separate harmonic current components; S102: Calculate the dispersed current and generated current at each harmonic frequency, and combine the dispersed current and generated current into the deviation current.

[0027] Since fundamental power is an important component in power system power analysis, this embodiment uses a bandpass filter to separate fundamental voltage and current from harmonic voltage and current, clarifying that power decomposition is only applied to harmonics.

[0028] At the fundamental frequency level, referring to traditional power decomposition, the fundamental current can be decomposed into the fundamental voltage, and further divided into active current and reactive current. At the harmonic level, the frequency components of energy consumption and energy generation are distinguished. Within the set of energy consumption frequencies, concepts such as equivalent harmonic impedance and harmonic active current are defined. The deviation between the harmonic impedance and the equivalent harmonic impedance at each harmonic frequency is defined as the dispersed current, and the harmonic current at the energy generation frequency is defined as the generating current. The calculation process for dispersed current and generating current is as follows: First, in order to quantify the energy interaction characteristics of the system in a specific frequency band, the active power needs to be calculated using real-time sampled data of node voltage and current. The integral calculation formula is as follows: ; in, Represents harmonic active power; and These represent the harmonic voltage and current data obtained from real-time sampling by the broadband measurement device, after processing by a digital filter. Based on this integral formula, combined with frequency domain decomposition, the active power within the energy-consuming harmonic set can be further calculated. .

[0029] Next, in order to evaluate the overall impedance deviation benchmark of the system at each harmonic frequency exhibiting energy dissipation characteristics, the equivalent harmonic conductance needs to be calculated, and the formula is as follows: ; in, Represents equivalent harmonic impedance; The effective value of the combined voltage corresponding to the above-mentioned energy-consuming harmonic set is obtained by calculating the root mean square of the voltage amplitude at the corresponding frequency.

[0030] Subsequently, based on the overall baseline obtained above, the harmonic active current corresponding to the system under ideal conditions is calculated, and its formula is: ; in, Represents harmonic active current; The time-domain waveform of the synthesized voltage corresponding to the set of energy-consuming harmonics is obtained by reconstructing the voltage components of the corresponding energy-consuming frequencies through inverse transformation. This step aims to establish a unified pure active power reference quantity.

[0031] Furthermore, in order to quantify the differential characteristics caused by the deviation of the actual conductance of each harmonic from the overall equivalent conductance in a real power grid, it is necessary to calculate the distributed current, the formula of which is: ; in, Represents dispersed current; This represents the set of energy-consuming frequencies where the active power is greater than zero. The actual harmonic impedance representing the h-th harmonic is obtained by dividing the voltage and current of that harmonic and taking the real part. This represents the instantaneous voltage of the h-th harmonic.

[0032] Finally, based on the orthogonal decomposition principle, the generated current actively injected into the grid by the nodes is accurately extracted from the total signal, and the formula is as follows: ; in, Represents the current generated; The value represents the harmonic reactive current, calculated according to the traditional orthogonal definition; the other parameters are obtained from the aforementioned steps.

[0033] The above is a power decomposition framework based on steady-state assumptions. However, transient conditions are more frequent in new power systems. To enable power analysis methods to better analyze power systems, a transient extension is made to the steady-state power decomposition. In this embodiment, the deviation current describing the deviation of harmonic admittance from equivalent admittance and the generating current describing active energy output are combined into a single deviation current. In actual operation, the deviation current is directly extracted.

[0034] The reason for merging the two currents in this embodiment to adapt to transient conditions is that, under non-stationary transient conditions, the frequency, amplitude, and phase of the signal exhibit rapidly changing time characteristics. If the distributed current and the generated current are calculated independently and decoupled, it not only requires a long data observation time window, but is also prone to introducing calculation errors or convergence delays due to the failure of the steady-state assumption. Merging the two currents eliminates the complex internal state stripping process, thereby significantly improving the algorithm's tracking speed and computational robustness under transient responses.

[0035] The combined deviation current characterizes the set of comprehensive abnormal disturbance components that cause the monitoring node to deviate from the ideal steady-state fundamental wave operating state.

[0036] S103: Based on the deviation current, an initial oscillation warning is performed using an adaptive envelope deviation criterion.

[0037] In this embodiment, during the process of broadband oscillation identification and source tracing based on instantaneous power decomposition, preliminary oscillation warning is first performed based on the adaptive envelope deviation criterion.

[0038] Specifically, definition To obtain the real-time envelope of the deviation current, calculate the average envelope of the deviation current over a past period. The adaptive envelope bias criterion is: ; in, This is the tolerance level, which can usually be set to 0.5-1.

[0039] If the above criteria are met, the system is determined to be unstable, and a preliminary oscillation warning is issued.

[0040] Deviation current is a high signal-to-noise ratio signal, and its anti-interference capability is far superior to that of traditional oscillation identification methods. In this embodiment, the envelope analysis of deviation current is used to perform preliminary oscillation early warning, reducing the waste of resources caused by unnecessary early warning.

[0041] S104: In response to the occurrence of the initial oscillation warning, a segment of deviation current data after the criterion response is extracted and subjected to spectrum analysis to determine whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation.

[0042] Consider a well-designed nonlinear load; its system must be asymptotically stable. According to the convergent system principle in nonlinear system theory, for a dissipative dynamic system under periodic external excitation... Under the influence of the action, its state trajectory Initial conditions will be ignored. It converges globally and asymptotically to a unique steady-state solution. Furthermore, the steady-state solution must inherit the periodicity of the excitation source.

[0043] This mechanistically proves that the response of a nonlinear load is forced to lock by the fundamental frequency of the power grid, and its output current... It must be strict Periodic function. This indicates that the energy storage element in a nonlinear load can only change the amplitude and phase of each integer multiple of the harmonics, but due to the periodic boundary conditions, it is impossible to create new frequency components that are not integer multiples.

[0044] System oscillations often occur in scenarios such as new energy converters with improperly configured parameters. Essentially, it indicates that the system has become unstable near a certain equilibrium point. At this point, the system's response is no longer determined by external excitation. The dominant factor is not the solution to its characteristic equation, but rather the oscillation frequency. It is entirely determined by the system's internal parameters.

[0045] This embodiment analyzes the frequency components of the deviation current based on the coupling relationship to determine whether the abnormal increase in deviation current is caused by oscillation.

[0046] Specifically, the analysis window is selected from 10 cycles of the adaptive envelope bias criterion response. FFT decomposition is then performed on this window to retrieve the frequencies corresponding to multiple amplitude peaks. Then, abnormal frequency determination is performed: ; in, Indicates the fundamental frequency. Represents an integer; As a criterion, if If the value is not an integer, it indicates that an abnormal frequency component has been detected in the deviation current, suggesting that the system is affected by oscillations, and the next step is to locate the oscillation source. If the value is an integer, it indicates that the deviation current contains frequency components that are integer multiples of the frequency, and thus can be analyzed in terms of harmonics.

[0047] S105: Perform frequency domain decomposition on the voltage and deviation current of the monitoring node, calculate the deviation power spectral density in the frequency domain; identify local extrema in the spectrum, and take the extrema points whose amplitude exceeds the preset multiple of the background noise as significant oscillation components, extract their corresponding frequencies as oscillation frequencies; locate the oscillation source according to the positive and negative values ​​of the deviation power spectral density.

[0048] To accurately quantify the flow of deviation energy in the frequency domain, this embodiment proposes a deviation power spectral density to characterize the power value at each frequency. The following section will mathematically define this physical quantity and derive its mechanism for determining the location of the oscillation source.

[0049] set up and These are the frequency domain expressions for the voltage and deviation current of the monitoring node, respectively.

[0050] According to signal processing theory, the time-domain integral of instantaneous power is equivalent to the cross-power spectrum integral in the frequency domain.

[0051] The complex deviation power spectrum is defined as follows: ; In the formula: yes .

[0052] Define the bias power spectral density Let be the real part of the bias power spectrum. Characterized at frequency At that point, the active power density carried by the deviation current.

[0053] This embodiment is based on the conventions of load models, and specifies that... In order to consume energy, To generate energy.

[0054] After the previous steps of screening, the time window in which the system is affected by oscillations was determined (i.e., the time window in which the oscillations occur was locked). At this point, frequency domain analysis is performed on the voltage and current data of all monitoring nodes to determine the properties of each node during oscillation: (1) Perform frequency domain decomposition on the voltage and deviation current of the monitoring node and calculate its deviation power spectral density; (2) Traverse the bias power spectral density, identify local extrema in the spectrum, and take the extrema points whose amplitude exceeds the preset multiple of the background noise as significant oscillation components, and extract their corresponding frequencies as oscillation frequencies. If multiple distinct values ​​exist, record the multiple frequencies. ; (3) If : Determine that the node is an energy-consuming node, i.e., the energy flow direction is towards this node; if The node is determined to be a power-generating node, meaning the energy flow direction is away from the node; thus, the oscillation source can be determined from the equipment side or the grid side based on the energy flow direction.

[0055] As a further implementation, all nodes that experience preliminary oscillation warnings are defined as affected monitoring nodes; the deviation power spectral density values ​​of all affected monitoring nodes are sorted, and the deviation power spectral density values ​​are used as feature weights to map onto the power grid spatial topology to construct a deviation power flow graph that characterizes the direction of oscillation energy transmission; based on the path of energy propagation from diverging nodes to dissipating nodes in the deviation power flow graph, the energy divergence starting point is traced and locked as a wide-area oscillation source.

[0056] As a further implementation plan, based on the aforementioned identified oscillation source and impedance information, the power system dispatch center can implement efficient mitigation strategies to eliminate broadband oscillations in a closed-loop manner. For example: At the emergency control level, the system can avoid the traditional one-size-fits-all approach of disconnecting the entire station, and only issue trip or rapid power reduction commands to the oscillation source, cutting off the injection path of unstable energy at the lowest load shedding cost; At the level of preventive and restorative control, the system can remotely reset the control parameters of the oscillation source based on the extracted impedance information, such as dynamically reducing the phase-locked loop bandwidth or introducing virtual impedance, to ensure the passivity of its ports from a physical source.

[0057] Using the model proposed in this embodiment, a grid-connected converter model is selected. The grid side is a three-phase 380V equivalent model, and the equipment side is a fully controlled converter model. The monitoring module is set as the PCC point, and a working condition in which a delay occurs due to the control of the current loop in the control loop is set.

[0058] Based on the aforementioned process, the specific verification results are as follows: The measured voltage and current waveforms at the PCC point are as follows: Figure 2 and 3 As shown; harmonic decomposition is performed on these voltages and currents, and the instantaneous decomposition diagrams of harmonic active current, reactive current, deviation current, and fundamental current obtained after S-transformation are shown in the figure. Figure 4 As shown; Figure 5 An adaptive envelope monitoring chart based on deviation current is presented. It can be seen that within the time range of 0.6s-0.7s, there are instances where the real-time envelope is larger than the average envelope, thus allowing for preliminary oscillation warning. Ten cycles following the adaptive envelope deviation criterion response are selected as the analysis window, and FFT decomposition is performed. The frequencies corresponding to multiple amplitude peaks are retrieved for anomaly detection. The results are as follows... Figure 6As shown, it can be seen that when the characteristic peak frequency is 426.9Hz, the criterion k is not an integer. Therefore, it can be determined that the system is affected by oscillations. Further frequency domain decomposition of the voltage and deviation current at the PCC point is performed, and the deviation power spectral density in the frequency domain is calculated, yielding significant oscillation components as shown below. Figure 7 As shown, by Figure 7 The oscillation frequency can be determined, and the oscillation source can be identified based on the sign of the deviation power spectral density. Finally, through verification using the method of this embodiment, it can be seen that the method of this embodiment can accurately detect an oscillation with a frequency of 426.9 Hz generated on the device side.

[0059] Example 2 In one or more embodiments, a unified monitoring system for broadband oscillation dynamic identification and source tracing is disclosed, specifically including: The data acquisition module is used to acquire current and voltage data of power system monitoring nodes and separate out harmonic current components; The transient power calculation module is used to calculate the dispersed current and the generated current at harmonic frequencies, and to combine the dispersed current and the generated current into a deviation current. The preliminary oscillation early warning module is used to perform preliminary oscillation early warning based on the deviation current and using an adaptive envelope deviation criterion. The oscillation identification module is used to respond to the occurrence of the initial oscillation warning by intercepting a segment of deviation current data after the criterion response, performing spectrum analysis, and determining whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation. The oscillation source localization module is used to perform frequency domain decomposition on the voltage and deviation current of the monitoring node, calculate the deviation power spectral density in the frequency domain, identify local extrema in the spectrum, and take the extrema points whose amplitude exceeds the preset multiple of the background noise as significant oscillation components, extract their corresponding frequencies as oscillation frequencies, and locate the oscillation source according to the positive and negative deviation power spectral density.

[0060] Furthermore, it also includes: a wide-area oscillation source localization module, which defines all nodes that have experienced preliminary oscillation warnings as affected monitoring nodes; sorts the deviation power spectral density values ​​of all affected monitoring nodes according to their magnitude, and maps the deviation power spectral density values ​​as feature weights to the power grid spatial topology to construct a deviation power flow graph characterizing the direction of oscillation energy transmission; and traces and locks the energy divergence starting point as the wide-area oscillation source based on the path of energy propagation from diverging nodes to dissipating nodes in the deviation power flow graph.

[0061] Example 3 In one or more embodiments, a terminal device is disclosed, comprising a processor and a memory, wherein the processor is used to implement instructions; and the memory is used to store multiple instructions adapted to be loaded by the processor and executed by the processor to perform the unified monitoring method for broadband oscillation dynamic identification and tracing described in Embodiment 1.

[0062] It should be understood that in this embodiment, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0063] Memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of memory may also include non-volatile random access memory. For example, memory may also store information about the device type.

[0064] In the implementation process, each step of the above method can be completed by the integrated logic circuits in the processor hardware or by software instructions.

[0065] Example 4 In one or more embodiments, a computer-readable storage medium is disclosed, wherein a plurality of instructions are stored, the instructions being adapted to be loaded by a processor of a terminal device and executed by the unified monitoring method for broadband oscillation dynamic identification and tracing described in Embodiment 1.

[0066] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A unified monitoring method for dynamic identification and source tracing of broadband oscillations, characterized in that, include: Acquire current and voltage data from power system monitoring nodes and separate out harmonic current components; Calculate the dispersed current and the generated current at the harmonic frequency, and combine the dispersed current and the generated current into a deviation current; Based on the aforementioned deviation current, an initial oscillation warning is provided using an adaptive envelope deviation criterion. In response to the occurrence of the initial oscillation warning, a segment of deviation current data after the criterion response is extracted and subjected to spectrum analysis to determine whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation. The voltage and deviation current of the monitoring node are decomposed in the frequency domain, and the deviation power spectral density in the frequency domain is calculated. Identify the extreme points in the deviation power spectral density where the amplitude exceeds a preset multiple of the background noise, and extract their corresponding frequencies as oscillation frequencies; locate the oscillation source based on the positive or negative deviation power spectral density.

2. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, The deviation between the harmonic impedance and the equivalent impedance at each harmonic frequency is defined as the dispersed current, the harmonic current at the generating frequency is defined as the generating current, and the sum of the two is defined as the deviation current.

3. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, Preliminary oscillation warning is performed using an adaptive envelope bias criterion, specifically as follows: Calculate the real-time envelope and average envelope of the deviation current respectively. If the real-time envelope is greater than the tolerance range of the average envelope, the system is judged to have started to oscillate and an early warning is issued.

4. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, A segment of deviation current data following the criterion response is extracted and subjected to spectrum analysis to determine whether abnormal frequency components exist in the deviation current. Specifically: After the criterion response, the deviation current data of the predetermined cycle is extracted and decomposed by FFT to determine the frequencies corresponding to multiple amplitude peaks. If the ratio of the frequency corresponding to at least one amplitude peak to the fundamental frequency is not an integer, that is, there is an abnormal frequency component, then the system is determined to have an oscillation fault.

5. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, The voltage and deviation current of the monitoring node are decomposed in the frequency domain, and the deviation power spectral density in the frequency domain is calculated, specifically as follows: The complex deviation power spectrum is calculated based on the complex conjugate product of the frequency domain voltage and the frequency domain deviation current of the monitoring node. The real part of the complex deviation power spectrum is the deviation power spectral density.

6. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, The oscillation source is located based on the positive and negative values ​​of the deviation power spectral density, specifically: If the deviation power spectral density value of the monitoring node is greater than zero, then the monitoring node is an energy-consuming node; if the deviation power spectral density value of the monitoring node is less than zero, then the monitoring node is an energy-generating node.

7. The unified monitoring method for dynamic identification and source tracing of broadband oscillations as described in claim 1, characterized in that, All nodes that trigger preliminary oscillation warnings are defined as affected monitoring nodes; the deviation power spectral density values ​​of all affected monitoring nodes are sorted, and the deviation power spectral density values ​​are used as feature weights to map onto the power grid spatial topology to construct a deviation power flow graph that characterizes the direction of oscillation energy transmission; based on the path of energy propagation from diverging nodes to dissipating nodes in the deviation power flow graph, the energy divergence starting point is traced and locked as a wide-area oscillation source.

8. A unified monitoring system for dynamic identification and source tracing of broadband oscillations, characterized in that, include: The data acquisition module is used to acquire current and voltage data of power system monitoring nodes and separate out harmonic current components; The transient power calculation module is used to calculate the dispersed current and generated current at each harmonic frequency, and to combine the dispersed current and generated current into a deviation current. The preliminary oscillation early warning module is used to perform preliminary oscillation early warning based on the deviation current and using an adaptive envelope deviation criterion. The oscillation identification module is used to respond to the occurrence of the initial oscillation warning by intercepting a segment of deviation current data after the criterion response, performing spectrum analysis, and determining whether there are abnormal frequency components in the deviation current; if so, it is determined that the system is affected by oscillation. The oscillation source location module is used to perform frequency domain decomposition on the voltage and deviation current of the monitoring node and calculate the deviation power spectral density in the frequency domain. Identify the extreme points in the deviation power spectral density where the amplitude exceeds a preset multiple of the background noise, and extract their corresponding frequencies as oscillation frequencies; locate the oscillation source based on the positive or negative deviation power spectral density.

9. A terminal device comprising a processor and a memory, the processor for implementing instructions; the memory for storing multiple instructions, characterized in that, The instructions are adapted to be loaded by a processor and executed by the unified monitoring method for dynamic identification and tracing of broadband oscillations as described in any one of claims 1-7.

10. A computer-readable storage medium storing a plurality of instructions, characterized in that, The instructions are adapted to be loaded by the processor of a terminal device and executed by the unified monitoring method for broadband oscillation dynamic identification and tracing as described in any one of claims 1-7.

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