Wide-band oscillation wide-area monitoring system and wide-band oscillation source localization method

Abstract

A wide-band oscillation wide-area monitoring system and a wide-band oscillation source localization method, which relate to the technical field of power system stability. The wide-band oscillation wide-area monitoring system comprises: a plurality of signal sensing modules, configured to acquire electrical signals from measured points; a plurality of wide-band measurement devices connected to the signal sensing modules, each wide-band measurement device being configured to perform spectrum analysis on the basis of electrical signals acquired by each signal sensing module, and generate oscillation alarm information on the basis of the spectrum analysis result, and the wide-band measurement devices being further configured to: in response to a waveform recording instruction, start to carry out waveform recording to generate waveform recording files for a same time section, and upload the waveform recording files and the spectrum analysis results; and a wide-band measurement master station in communication connection with each wide-band measurement device, the wide-band measurement master station being configured to: on the basis of the oscillation alarm information uploaded by each wide-band measurement device, determine whether a wide-band oscillation risk is present for a power system, and if so, send the waveform recording instruction to all of the wide-band measurement devices, and on the basis of the spectrum analysis result fed back by each wide-band measurement device, perform oscillation source localization.

Description

Broadband oscillation wide-area monitoring system and broadband oscillation source positioning method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 24, 2023, with application number 202311377961.X and invention name “Wideband Oscillation Wide Area Monitoring System and Wideband Oscillation Source Positioning Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of power system stability, and in particular to a broadband oscillation wide-area monitoring system and a broadband oscillation source positioning method. Background Art

[0003] Traditional power systems are equipped with Supervisory Control and Data Acquisition (SCA / DA) and Wide Area Measurement System (WAMS), which mainly focus on the measurement of power frequency phasors. Signals in other frequency bands are mostly filtered out by bandpass filters. However, with the development of power systems, especially the development of new energy technologies, more and more new energy units and new transmission technologies will be connected to the power system.

[0004] Taking offshore wind turbines as an example, Flexible High Voltage Direct Current (VSC-HVDC) transmission is becoming the mainstream choice for long-distance offshore wind power transmission. However, the interaction between the offshore wind turbine's power electronic converter and the VSC-HVDC can cause broadband oscillations with frequencies ranging from a few Hz to several thousand Hz. As the scale of offshore wind farms continues to expand, the problem of broadband oscillations has become increasingly prominent, seriously affecting the safety and stability of the power system and becoming a major factor restricting the effective absorption of renewable energy such as offshore wind power.

[0005] Therefore, the wide-area measurement system configured in the traditional power system cannot meet the measurement frequency band requirements of broadband measurement. There is an urgent need for wide-area monitoring technology that supports monitoring of broadband oscillation events to maintain the stability of the power system.

[0006] Summary of the Invention

[0007] The purpose of this application is to solve at least one of the above technical deficiencies, particularly the problem that the wide area monitoring system in the prior art does not support broadband oscillation monitoring.

[0008] In a first aspect, the present application provides a broadband oscillation wide-area monitoring system, comprising:

[0009] Multiple signal sensing modules, the signal sensing modules are used to collect electrical signals from the measured points;

[0010] Multiple broadband measurement devices are connected to the signal sensing modules and are used to perform spectrum analysis based on the electrical signals collected by each signal sensing module and generate oscillation alarm information based on the spectrum analysis results. They are also used to respond to recording instructions, start recording, generate recording files for the same time section, and upload the recording files and spectrum analysis results;

[0011] The broadband measurement master station is connected to each broadband measurement device for determining whether there is a broadband oscillation risk in the power system based on the oscillation alarm information uploaded by each broadband measurement device. When it is determined that there is a broadband oscillation risk, it sends a recording instruction to all broadband measurement devices and locates the oscillation source based on the spectrum analysis results fed back by each broadband measurement device.

[0012] In one embodiment, the broadband measurement device is used to determine the content of each harmonic in the electrical signal based on the spectrum analysis result, and generate oscillation alarm information when the content exceeds the corresponding content threshold, and send it to the broadband measurement master station.

[0013] In one embodiment, the broadband measurement master station is used to send the content threshold to each broadband measurement device.

[0014] In one embodiment, the broadband measurement device is further configured to sample the electrical signal to obtain a waveform sequence corresponding to the electrical signal, and upload the waveform sequence to the broadband measurement master station.

[0015] In one embodiment, the broadband measurement master station is connected to each broadband measurement device via a 5G network communication connection, the spectrum analysis results, waveform sequence and recording instructions are transmitted via the uRLLC protocol, and the recording files and content thresholds are transmitted via the eMBB protocol.

[0016] In a second aspect, an embodiment of the present application provides a method for locating a broadband oscillation source, which is applied to a broadband measurement master station in a broadband oscillation wide-area monitoring system in any of the above embodiments. The method for locating a broadband oscillation source includes:

[0017] Based on the oscillation alarm information uploaded by each broadband measurement device, determine whether there is a broadband oscillation risk in the power system;

[0018] When a broadband oscillation risk is determined, a recording instruction is sent to all broadband measurement devices. The recording instruction is used to instruct the broadband measurement devices to start recording to generate recording files of the same time section, and upload the recording files and spectrum analysis results to the broadband measurement master station.

[0019] The oscillation source is located based on the spectrum analysis results fed back by each broadband measurement device.

[0020] In one embodiment, judging whether there is a risk of broadband oscillation in the power system based on the oscillation alarm information uploaded by each broadband measurement device includes:

[0021] When the number of received oscillation warning information is greater than the determination threshold, it is determined that there is a broadband oscillation risk in the power system.

[0022] In one embodiment, locating the oscillation source based on the spectrum analysis results fed back by each broadband measurement device includes:

[0023] The spectrum analysis results fed back by each broadband measurement device are spliced ​​together to obtain a wide-area broadband spectrum information set;

[0024] Oscillation source location is performed based on wide-area broadband spectrum information set.

[0025] In one embodiment, spectrum analysis results fed back by each broadband measurement device are spliced ​​together to obtain a wide-area broadband spectrum information set, including:

[0026] According to the topological connection relationship between the measured points corresponding to each broadband measurement device, the spectrum analysis results fed back by each broadband measurement device are spliced ​​to obtain a wide-area broadband spectrum information set.

[0027] In one embodiment, locating an oscillation source based on a wide-area broadband spectrum information set includes:

[0028] Traversing each harmonic in the target frequency band, and determining the traversed harmonic as the target harmonic;

[0029] For the current target harmonic, any node in the power system is selected as the target node;

[0030] Based on the target node, the power system is subjected to Norton equivalence;

[0031] Determine, based on the equivalent model, a first equivalent impedance of the target node on the first side and a second equivalent impedance on the second side;

[0032] Taking the current component of the target harmonic at the first side of the target node as the first current and the current component of the target harmonic at the second side as the second current, the first current and the second current are determined according to the wide-area broadband spectrum information set;

[0033] Determining, based on the first current, the first equivalent impedance, the second current, and the second equivalent impedance, that the inflow side of the oscillation power of the target harmonic is the first side or the second side;

[0034] Determine whether the inflow side corresponding to the current target node and the inflow side corresponding to the previous target node have changed;

[0035] If not, the node connected to the current target node on the inflow side is determined as the new target node, and the step of performing Norton equivalence on the power system based on the target node is returned to continue execution;

[0036] If so, it is determined that the oscillation source of the target harmonic is located between the current target node and the previous target node.

[0037] In one embodiment, determining the inflow side of the oscillation power of the target harmonic as the first side or the second side according to the first current, the first equivalent impedance, the second current, and the second equivalent impedance includes:

[0038] determining a product of the first current and the first equivalent impedance as a first product;

[0039] determining the product of the second current and the second equivalent impedance as a second product;

[0040] If the absolute value of the first product is greater than the absolute value of the second product, the inflow side is determined to be the first side;

[0041] If the absolute value of the first product is smaller than the absolute value of the second product, it is determined that the inflow side is the second side.

[0042] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0043] Based on any of the above embodiments, the broadband oscillation wide-area monitoring function is realized through the signal sensing, broadband measurement, and management master station functional modules. Among them, the broadband measurement device can timely detect the harmonic oscillation risk at the measured point by spectrum analysis of the electrical signal, and report it to the broadband measurement master station in time. The broadband measurement master station can thus judge the harmonic oscillation situation of the entire power system based on the oscillation alarm information, and when it is determined that there is a broadband oscillation risk, it instructs all broadband measurement devices to start recording synchronously, so as to facilitate the subsequent further analysis of the status of the power system when the broadband vibration risk occurs based on the recording file, and can also locate the oscillation source based on the spectrum analysis results. The system has a clear structure, distinct levels, and strong feasibility in engineering applications. It is particularly suitable for broadband oscillation wide-area monitoring in offshore wind power grid-connected scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0045] FIG1 is a schematic structural diagram of a broadband oscillation wide-area monitoring system provided by one embodiment of the present application;

[0046] FIG2 is a schematic diagram of the communication structure of a broadband oscillation wide-area monitoring system provided by one embodiment of the present application;

[0047] FIG3 is a schematic diagram of a flow chart of a method for locating a broadband oscillator source according to an embodiment of the present application;

[0048] FIG4 is a schematic diagram showing the principle of performing Norton equivalence based on a target node in one embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] Please refer to FIG. 1 . The present application provides a broadband oscillation wide-area monitoring system, which includes a plurality of signal sensing modules 10 , a plurality of broadband measurement devices 20 and a broadband measurement master station 30 .

[0051] The signal sensing module 10 is used to collect electrical signals from the measured points. It will be understood that the electrical signals referred to here include current and voltage signals. The signal sensing module 10 may include a current sensor and a voltage sensor. After collecting the electrical signals, the signal sensing module 10 outputs them to the corresponding broadband measurement device 20. The selection of measured points can be based on the needs of wide-area monitoring and relevant power system regulations. Generally, each node in the power system and the lines on both sides of the nodes can be selected as measured points.

[0052] The broadband measurement device 20 is connected to the signal sensing module 10 and is configured to perform spectrum analysis on the electrical signals collected by each signal sensing module 10 and generate oscillation warning information based on the spectrum analysis results. It can be understood that spectrum analysis refers to extracting harmonic components from the electrical signal using a preset algorithm to obtain phasor information, such as the amplitude and phase of each harmonic contained in the electrical signal. Specifically, the broadband measurement device 20 can be configured with an A / D sampling module and a spectrum analysis module. The A / D sampling module samples the analog electrical signal output by the signal sensing module 10 and converts it into a corresponding waveform sequence. The A / D sampling module then outputs the waveform sequence to the spectrum analysis module. The spectrum analysis module performs spectrum analysis based on the waveform sequence and a preset algorithm to obtain expressions for each harmonic component in the current and voltage signals, thereby extracting the amplitude, phase, and other information of each harmonic. In some embodiments, the preset algorithm can be a fast Fourier transform, a wavelet transform and its improved algorithms, a Hilbert-Huang transform, or the like, as long as it can accurately extract harmonics within the target frequency band.

[0053] Since spectrum analysis includes phasor information for each harmonic of an electrical signal within the target frequency band, harmonics other than the fundamental wave can potentially impact system stability in a power system. Therefore, based on the spectrum analysis results, the broadband measurement device 20 can detect in real time whether harmonic oscillation is occurring at the point it monitors, and promptly send an oscillation warning message to the broadband measurement master station 30 if such oscillation occurs. The broadband measurement master station 30 is in communication with each broadband measurement device 20. Based on the oscillation warning information uploaded by each broadband measurement device 20, it determines whether the power system is at risk of broadband oscillation. If a broadband oscillation risk is determined, it sends a recording instruction to all broadband measurement devices 20, instructing them to simultaneously begin recording, recording the waveforms and data of certain fault-related characteristic quantities in the power system when an oscillation fault occurs. Generally speaking, in addition to the waveforms of current and voltage signals, the recording file also records data such as the operation sequence of protection and safety automatic devices, system frequency, active power, reactive power, negative-sequence current, zero-sequence current, negative-sequence voltage, and zero-sequence voltage. This data can be used to analyze the harmonic oscillation process, its impact, and the operation of protective devices. The broadband measurement device 20 shown in Figure 1 also includes a data storage module for storing collected data or processing results required for operation and as needed. The broadband measurement device 20 also communicates with the broadband measurement master station 30 via a communication module.

[0054] The broadband measurement master station 30 will locate the oscillation source based on the spectrum analysis results fed back by each broadband measurement device 20. If the harmonic component detected by the broadband measurement device 20 and having a harmonic oscillation problem is used as the target harmonic, the oscillation source location is used to find the source of the target harmonic from the power system. For example, when it is found that the third harmonic has a harmonic oscillation problem, the third harmonic is used as the target harmonic, and the oscillation source location is used to find the location of the source of the third harmonic from the power system. In some embodiments, in order to conduct a comprehensive analysis of the harmonic situation of the power system, all harmonics of all orders within the target frequency band that the broadband oscillation wide-area monitoring system is responsible for monitoring can also be selected as target harmonics.

[0055] Specifically, the broadband measurement master station 30 is equipped with a broadband oscillation identification module, an oscillation source location module, a constant value setting module, and a data management module. The broadband oscillation identification module is used to determine whether there is a broadband oscillation risk in the power system based on the oscillation alarm information uploaded by each broadband measurement device 20, and when it is determined that there is a broadband oscillation risk, it sends a recording instruction to all broadband measurement devices 20. The oscillation source location module is used to locate the oscillation source based on the spectrum analysis results fed back by each broadband measurement device 20. The constant value setting module is used to issue the constant values ​​required for certain judgment conditions to each broadband measurement device 20, as well as the constant values ​​required for certain judgment conditions required for its own operation. The data management module is used to uniformly manage the data generated by the broadband measurement master station 30 itself and the data reported by each broadband measurement device 20.

[0056] To facilitate operations, observation, monitoring, and control at the broadband measurement master station 30, a human-computer interaction platform 40 is deployed. Through the human-computer interaction platform 40, workers can perform data visualization, query, data analysis, and remote control operations at the broadband measurement master station 30.

[0057] Based on the broadband oscillation wide-area monitoring system in this embodiment, the broadband oscillation wide-area monitoring function is realized through several major functional modules such as signal sensing, broadband measurement, and management master station. Among them, the broadband measurement device 20 can timely detect the harmonic oscillation risk at the measured point by analyzing the spectrum of the electrical signal, and report it to the broadband measurement master station 30 in a timely manner. The broadband measurement master station 30 can thus judge the harmonic oscillation situation of the entire power system based on the oscillation alarm information, and when it is determined that there is a broadband oscillation risk, it instructs all broadband measurement devices 20 to start recording synchronously, so as to facilitate the subsequent further analysis of the status of the power system when the broadband vibration risk occurs based on the recording file, and can also locate the oscillation source based on the spectrum analysis results. The system has a clear structure, distinct levels, and strong feasibility in engineering applications. It is particularly suitable for broadband oscillation wide-area monitoring in offshore wind power grid-connected scenarios.

[0058] In one embodiment, the broadband measurement device 20 is configured to determine the harmonic content of each subharmonic in the electrical signal based on spectrum analysis results. When the content exceeds a corresponding content threshold, it generates an oscillation alarm message and transmits it to the broadband measurement master station 30. It is understood that when the broadband measurement device 20 detects that the harmonic content at the measured point exceeds the standard, the entire system may be experiencing broadband oscillation. Therefore, when the broadband measurement device 20 detects that the harmonic content exceeds the standard based on the spectrum analysis results and the corresponding content thresholds of each subharmonic, it transmits an oscillation alarm message to the broadband measurement master station 30. In some embodiments, the broadband measurement master station 30 is configured to transmit the content threshold to each broadband measurement device 20. Specifically, the broadband measurement master station 30 can set the harmonic content determination threshold for each broadband measurement device 20 as needed, thereby enabling the broadband measurement master station 30 to manage and lead the entire system.

[0059] In one embodiment, the broadband measurement device 20 is further configured to sample electrical signals, obtain waveform sequences corresponding to the electrical signals, and upload the waveform sequences to the broadband measurement master station 30. Specifically, the broadband measurement master station 30 can choose to subscribe to required data from each broadband measurement device 20, with one of the subscribed topics being the waveform data of the electrical signals. The electrical signals output by the signal sensing module 10 to the broadband measurement device 20 are analog, which is not conducive to remote transmission of the broadband measurement device 20 to the broadband measurement master station 30. Therefore, the broadband measurement device 20 can use its internal A / D sampling module to sample the electrical signals and generate waveform sequences corresponding to the current signal and voltage signal, respectively. These waveform sequences are digital, enabling transmission with higher communication quality and lower communication latency. Furthermore, long-term sampling imposes a significant workload on the broadband measurement device 20. Therefore, the broadband measurement device 20 can choose to periodically transmit the waveform sequences corresponding to the electrical signals to the broadband measurement master station 30, or it can transmit the waveform sequences corresponding to the electrical signals at the direction of the broadband measurement master station 30.

[0060] In one embodiment, the broadband measurement master station 30 is connected to each broadband measurement device 20 via 5G network communication. Due to the scarcity of communication resources in many subdivided scenarios of the power system, and the high construction cost and difficult operation and maintenance of communication networks such as optical fibers and cables, it is particularly necessary to perform broadband oscillation wide-area monitoring in offshore wind power scenarios. Therefore, this embodiment designs a special communication architecture to address this problem. As shown in Figure 2, the uRLLC (Ultra-Reliable Low-Latency Communication) protocol and the eMBB (Enhanced Mobile Broadband) protocol are two different protocols for 5G application scenarios. The uRLLC protocol is characterized by high reliability, low latency, and extremely high availability. In this embodiment, the spectrum analysis results, waveform sequences, and recording instructions generally need to be transmitted between the broadband measurement master station 30 and the broadband measurement device 20 only when there is a risk of broadband oscillation in the system. There are high requirements for latency, so the characteristic-matching uRLLC protocol is selected for transmission. The eMBB protocol is characterized by high speed, high capacity, and high density. The volume of the recorded files is large, but the content threshold has low requirements for latency, so it is chosen to be transmitted through the eMBB protocol.

[0061] An embodiment of the present application provides a method for locating a broadband oscillation source, which is applied to a broadband measurement master station in a broadband oscillation wide-area monitoring system in any of the above embodiments. Referring to FIG. 3 , the method for locating a broadband oscillation source includes steps S302 to S306 .

[0062] S302 : Determine whether there is a broadband oscillation risk in the power system based on the oscillation alarm information uploaded by each broadband measurement device.

[0063] It can be understood that when the broadband measurement master station receives an oscillation alarm message, it means that there is a harmonic oscillation at a certain measured point. However, from the perspective of the entire power system, only when multiple measured points are reporting alarms can it be determined that the power system is at risk of broadband oscillation. Specifically, the discrimination ratio can be set in the constant value setting module. The broadband measurement master station determines the discrimination threshold based on the number of broadband measurement devices currently online and the discrimination ratio. When the number of oscillation alarm messages received exceeds the discrimination threshold, the broadband measurement master station determines that the power system is at risk of broadband oscillation. For example, when there are 5 broadband measurement devices online and the discrimination ratio is 40%, it can be determined that the power system is at risk of broadband oscillation when more than three oscillation alarm messages are received.

[0064] S304: If a broadband oscillation risk is determined, a recording instruction is sent to all broadband measurement devices. This recording instruction instructs the broadband measurement devices to record the electrical signals output by the connected signal sensor modules, generate recording files for the same time section, and upload the recording files and spectrum analysis results to the broadband measurement master station.

[0065] It can be understood that the recording file can record the waveforms and data of certain fault-related characteristic quantities in the power system when an oscillation fault occurs. Generally speaking, in addition to the waveforms of current signals and voltage signals, the recording file also records data such as the action sequence of relevant protection and safety automatic devices, system frequency, active power, reactive power, negative sequence current, zero sequence current, negative sequence voltage, and zero sequence voltage. These data can be used to analyze the process and impact of harmonic oscillations and the action of protection devices. The spectrum analysis results are the input of the tracing algorithm set up in the broadband measurement master station. Therefore, when determining that there is a risk of broadband oscillation in the power system, it is necessary to obtain the spectrum analysis results from the broadband measurement device and store the recording file to facilitate subsequent fault analysis.

[0066] S306: locating the oscillation source based on the spectrum analysis results fed back by each broadband measurement device.

[0067] In one embodiment, locating the oscillation source based on the spectrum analysis results fed back by each broadband measurement device includes:

[0068] (1) The spectrum analysis results fed back by each broadband measurement device are spliced ​​to obtain a wide-area broadband spectrum information set.

[0069] Specifically, the spectrum analysis results fed back by each broadband measurement device are combined into a data set. Based on the topological connection relationship between the measured points corresponding to each broadband measurement device, the spectrum analysis results fed back by each broadband measurement device can be spliced ​​together to obtain a wide-area broadband spectrum information set. Specifically, in a database, the spectrum analysis results fed back by different broadband measurement devices can be annotated based on the connection relationship between the measured points corresponding to each broadband measurement device. This allows operations such as data query and index creation to be better integrated with the grid structure.

[0070] (2) Locate the oscillation source based on the wide-area broadband spectrum information set.

[0071] In one embodiment, locating an oscillation source based on a wide-area broadband spectrum information set includes:

[0072] (1) Traverse the target harmonics in the target frequency band.

[0073] The target frequency band is the frequency band required for wide-area broadband oscillation monitoring. The target frequency band can be any frequency band within 2500 Hz. The target harmonic is a specific harmonic order related to the harmonic oscillation within the target frequency band. There can be more than one target harmonic within the target frequency band, and the oscillation source locations of harmonics of different orders may vary. Therefore, it is necessary to traverse the target harmonics within the target frequency band.

[0074] (2) For the current target harmonic, any node in the power system is selected as the target node.

[0075] The current target harmonic refers to the target harmonic traversed in this round. A topological diagram, abstracted from the actual structure of a power system, generally consists of nodes and lines. A node in a power system is typically a current collection point or branch collection point in power grid calculations and analysis. This typically corresponds to a busbar, for example. To trace a source within a power system, first select an arbitrary node as the starting point and begin tracing from that node.

[0076] (3) Based on the target node, the power system is subjected to Norton equivalence.

[0077] It can be understood that, with the target node and the ground as the endpoints, the systems on the first and second sides of the target node are equivalent to a current source and an impedance in parallel. t Represents the voltage of the target node at the target harmonic frequency, I t Represents the current of the target node at the target harmonic frequency. I M Represents the current of the Norton equivalent current source on the first side of the target node at the target harmonic frequency, Z M Represents the impedance of the Norton equivalent current source on the first side of the target node at the target harmonic frequency. I P Represents the current of the Norton equivalent current source on the second side of the target node at the target harmonic frequency, Z P Represents the impedance of the Norton equivalent current source on the second side of the target node at the target harmonic frequency.

[0078] (4) Based on the equivalent model, determine a first equivalent impedance of the target node on the first side and a second equivalent impedance on the second side.

[0079] It is understood that, since the grid structure of the power system is known, the equivalent impedances on both sides of the target node can be analyzed separately, thereby determining the first and second equivalent impedances. Furthermore, it is worth noting that, since this embodiment analyzes target harmonics of a specific order, when deriving the expressions for the first and second equivalent impedances, the specific values ​​of the first and second equivalent impedances should be calculated based on the frequency of the target harmonic, as the capacitive and inductive reactances in the impedances are frequency-dependent.

[0080] (5) The current component of the target harmonic on the first side of the target node is taken as the first current, and the current component of the target harmonic on the second side is taken as the second current, and the first current and the second current are determined according to the wide-area broadband spectrum information set.

[0081] It can be understood that the measured points in the power system include both sides of each node in the power system. The wide-area broadband spectrum information set includes the current components corresponding to each harmonic at the measured point within the target frequency band. The current of the Norton equivalent current source on the first side of the target node is equal to the first current, and the current of the Norton equivalent current source on the second side of the target node is equal to the second current. The first current and the second current can be extracted from the wide-area broadband spectrum information set.

[0082] (6) Determine, based on the first current, the first equivalent impedance, the second current, and the second equivalent impedance, whether the inflow side of the oscillation power of the target harmonic is the first side or the second side.

[0083] It can be understood that the active power flow method adopted in this application has a clear physical meaning, simple calculation, good effect, and is suitable for online identification of broadband oscillation sources. Specifically, at the frequency of the target harmonic, by judging whether the active power flows into or out of the target node, it can be determined whether the oscillation source at the target harmonic frequency is located on the first side or the second side. The active power P of the target node at the target harmonic frequency is t It can be expressed as:

[0084] From this formula, we can get that when P t When P is greater than 0, the oscillation active power flows into the target node from the second side, that is, the oscillation source is located on the second side. t When it is less than 0, the oscillating active power flows into the target node from the first side, meaning the oscillation source is located on the first side. Based on this, the product of the first current and the first equivalent impedance is determined as the first product, and the product of the second current and the second equivalent impedance is determined as the second product. If the absolute value of the first product is greater than the absolute value of the second product, the inflow side is determined to be the first side; if the absolute value of the first product is less than the absolute value of the second product, the inflow side is determined to be the second side.

[0085] (7) Determine whether the inflow side corresponding to the current target node and the inflow side corresponding to the previous target node have changed.

[0086] (8) If not, the node connected to the current target node on the inflow side is determined as the new target node, and the step of performing Norton equivalence on the power system based on the target node is returned to continue execution.

[0087] (9) If so, it is determined that the oscillation source of the target harmonic is located between the current target node and the previous target node.

[0088] It can be understood that in this embodiment, the oscillation source is approached step by step against the flow direction of active power, and the oscillation source is finally located. If the inflow side corresponding to the current target node and the inflow side corresponding to the previous target node do not change, it means that the active power is transmitted from the same side of the current target node and the previous target node, which means that the oscillation source has not been passed during the tracing process. It is necessary to continue to search again against the flow direction of active power, that is, to determine the node connected to the current target node on the inflow side as the new target node, and return to step (3) to continue tracing. When it is found that the inflow side has changed, it can be determined that the oscillation source has been crossed, so it can be determined that the oscillation source is between the current target node and the previous target node, and the oscillation source can be located.

[0089] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referenced to each other.

[0090] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A broadband oscillation wide-area monitoring system, characterized in that: include: A plurality of signal sensing modules, wherein the signal sensing modules are used to collect electrical signals of the measured points; A plurality of broadband measuring devices are connected to the signal sensing modules, and are used to perform spectrum analysis on the electrical signals collected by the signal sensing modules, and to generate oscillation alarm information based on the spectrum analysis results, and are also used to respond to a wave recording instruction, start wave recording, so as to generate a wave recording file of the same time section, and upload the wave recording file and the spectrum analysis results; The broadband measurement master station is communicatively connected with each of the broadband measurement devices, and is used to determine whether there is a broadband oscillation risk in the power system based on the oscillation alarm information uploaded by each of the broadband measurement devices, and when it is determined that there is a broadband oscillation risk, send the recording instruction to all the broadband measurement devices, and locate the oscillation source based on the spectrum analysis results fed back by each of the broadband measurement devices.

2. The broadband oscillation wide-area monitoring system according to claim 1, characterized in that: The broadband measurement device is used to determine the content of each harmonic in the electrical signal according to the spectrum analysis result, and to generate the oscillation alarm information when the content exceeds the corresponding content threshold, and send it to the broadband measurement master station.

3. The broadband oscillation wide-area monitoring system according to claim 2, characterized in that: The broadband measurement master station is used to send the content threshold to each of the broadband measurement devices.

4. The broadband oscillation wide-area monitoring system according to claim 3, characterized in that: The broadband measurement device is also used to sample the electrical signal to obtain a waveform sequence corresponding to the electrical signal, and upload the waveform sequence to the broadband measurement main station.

5. The broadband oscillation wide-area monitoring system according to claim 4, characterized in that: The broadband measurement master station is connected to each of the broadband measurement devices via a 5G network communication, the spectrum analysis results, the waveform sequence and the recording instructions are transmitted via the uRLLC protocol, and the recording file and the content threshold are transmitted via the eMBB protocol.

6. A method for locating a broadband oscillation source, characterized in that: The broadband measurement master station used in the broadband oscillation wide-area monitoring system according to any one of claims 1 to 5, wherein the broadband oscillation source positioning method comprises: According to the oscillation alarm information uploaded by each broadband measurement device, determining whether there is a broadband oscillation risk in the power system; When it is determined that there is the risk of broadband oscillation, a wave recording instruction is sent to all the broadband measurement devices; the wave recording instruction is used to instruct the broadband measurement devices to record waves to generate wave recording files of the same time section, and upload the wave recording files and spectrum analysis results to the broadband measurement master station; The oscillation source is located based on the spectrum analysis results fed back by each of the broadband measurement devices.

7. The broadband oscillation source positioning method according to claim 6, characterized in that: The determining whether there is a broadband oscillation risk in the power system according to the oscillation alarm information uploaded by each broadband measurement device includes: When the number of the received oscillation warning information is greater than the determination threshold, it is determined that the power system has the broadband oscillation risk.

8. The broadband oscillation source positioning method according to claim 6, characterized in that: The oscillation source positioning based on the spectrum analysis results fed back by each of the broadband measurement devices includes: Performing data splicing on the spectrum analysis results fed back by each of the broadband measurement devices to obtain a wide-area broadband spectrum information set; The oscillation source is located according to the wide-area broadband spectrum information set.

9. The broadband oscillation source positioning method according to claim 8, characterized in that: The data splicing of the spectrum analysis results fed back by each of the broadband measurement devices to obtain a wide-area broadband spectrum information set includes: According to the topological connection relationship between the measured points corresponding to each of the broadband measurement devices, the spectrum analysis results fed back by each of the broadband measurement devices are data spliced ​​to obtain a wide-area broadband spectrum information set.

10. The broadband oscillation source positioning method according to claim 8, characterized in that: The oscillation source positioning according to the wide-area broadband spectrum information set includes: Traversing each target harmonic in the target frequency band; For the current target harmonic, select any one node from among the nodes of the power system as a target node; Based on the target node, performing Norton equivalence on the power system; Based on the equivalent model, determining a first equivalent impedance of the target node on the first side and a second equivalent impedance on the second side; Taking the current component of the target harmonic of the target node on the first side as the first current and the current component of the target harmonic of the target node on the second side as the second current, determining the first current and the second current according to the wide-area broadband spectrum information set; Determining, according to the first current, the first equivalent impedance, the second current, and the second equivalent impedance, that an inflow side of the oscillation power of the target harmonic is the first side or the second side; Determine whether the inflow side corresponding to the current target node is changed from the inflow side corresponding to the previous target node; If not, determine the node connected to the current target node on the inflow side as the new target node, and return to the step of performing Norton equivalence on the power system based on the target node to continue executing; If so, it is determined that the oscillation source of the target harmonic is located between the current target node and the previous target node.

11. The broadband oscillation source positioning method according to claim 10, characterized in that: The step of determining, according to the first current, the first equivalent impedance, the second current, and the second equivalent impedance, that the inflow side of the oscillation power of the target harmonic is the first side or the second side includes: determining a product of the first current and the first equivalent impedance as a first product; determining the product of the second current and the second equivalent impedance as a second product; If the absolute value of the first product is greater than the absolute value of the second product, determining that the inflow side is the first side; If the absolute value of the first product is smaller than the absolute value of the second product, it is determined that the inflow side is the second side.

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