Wide-area source tracing method, system, equipment and storage medium for broadband oscillations in power grids

Abstract

This invention belongs to the field of power system automation and discloses a method, system, equipment, and storage medium for wide-area oscillation tracing in power grids. The method includes: acquiring oscillation characteristic information of each substation node; identifying the oscillating substation node and its oscillating current flow direction based on the oscillation characteristic information; acquiring the oscillation amplitude of each oscillating substation node; and determining the oscillation propagation direction of each oscillating substation node based on the oscillation amplitude and oscillating current flow direction; and tracing the oscillation source based on its propagation direction to obtain the oscillation source. This enables accurate analysis of the oscillation propagation path and its impact range, achieving oscillation source tracing and accurate location, thereby providing strong support for power grid operation monitoring and targeted oscillation suppression, effectively supporting dispatching and operation monitoring operations, and ensuring power grid operation safety.

Description

Technical Field

[0001] This invention belongs to the field of power system automation and relates to a method, system, device and storage medium for wide-area tracing of power grid broadband oscillations. Background Technology

[0002] With the large-scale integration of new energy sources such as photovoltaics and wind power, and the application of high-voltage direct current (HVDC) and flexible direct current (DC) transmission technologies, power electronic devices are widely used in power systems. This injects a large number of low-frequency and high-frequency signals into the power grid, leading to an increasing content of subsynchronous / supersynchronous oscillation signals and a diversification of interharmonic content in various non-integer multiples of the power frequency. This results in broadband signal characteristics in the power grid, posing new challenges to current power grid monitoring. Meanwhile, new power systems based on new energy sources have become the future development direction. The large-scale grid connection of inverters in these new power systems significantly increases the proportion of power electronic devices in the power grid, gradually leading to a trend of power electronicization in the entire power system and exacerbating the occurrence of grid oscillation events.

[0003] Currently, oscillations in the power grid are gradually exhibiting two prominent characteristics: firstly, the oscillation frequency is shifting from low to medium-high frequencies, showing a trend towards a wide frequency range; secondly, the oscillations are evolving from traditional electromechanical transients to electromagnetic transients. These new electromagnetic transient oscillations are entirely caused by interactions between power electronic equipment and the power grid, and between different power electronic equipment, and do not involve traditional synchronous motors, such as thermal power units and hydropower units. These new broadband oscillations pose challenges to the safe and stable operation of the current power grid, urgently requiring accurate location of the oscillation source and timely suppression to further reduce the harmful effects of oscillations.

[0004] The large-scale integration of high-proportion renewable energy sources and the application of high-proportion power electronic equipment have triggered a series of novel broadband oscillation events. Although some power plants and substations have real-time monitoring capabilities for broadband oscillations, the dispatching master station still lacks the ability to monitor and trace the oscillations over a wide area. This makes it impossible to fully display the oscillation propagation path and impact range, or accurately locate the oscillation source, hindering the provision of precise oscillation suppression guidance for dispatching personnel and seriously affecting the operational safety of the power grid. Therefore, to effectively address the broadband oscillation problem, it is urgent to conduct research on broadband oscillation wide-area source tracing methods to provide strong support for oscillation source location. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, device and storage medium for wide-area tracing of power grid broadband oscillations.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for tracing the source of wide-range oscillations in power grids, comprising:

[0008] Obtain oscillation characteristic information of nodes in various power plants and stations within a wide area;

[0009] Based on the oscillation characteristic information of each plant node, the oscillating plant node in each plant node and the oscillation current flow direction of each oscillating plant node are obtained.

[0010] The oscillation amplitude of each oscillation power plant node is obtained. Based on the oscillation amplitude of each oscillation power plant node and the direction of oscillation current flow of each oscillation power plant node, the oscillation propagation direction of each oscillation power plant node is obtained.

[0011] The oscillation source is obtained by tracing the oscillation propagation direction of each oscillation station node.

[0012] Optionally, the oscillation characteristic information of each plant node is transmitted to the dispatch master station in real time by each plant node; the oscillation characteristic information includes: oscillation frequency and oscillation amplitude and oscillation phase of each oscillation frequency;

[0013] The oscillation amplitude includes the oscillation power amplitude, the oscillation voltage amplitude, and the oscillation current amplitude; the oscillation phase includes the oscillation voltage phase and the oscillation current phase.

[0014] Optionally, the step of obtaining the oscillating plant nodes among the plant nodes based on the oscillation characteristic information of each plant node includes:

[0015] The dominant oscillation frequency f is obtained through equation (1) or equation (2). main :

[0016]

[0017]

[0018] Where k is the plant node number, n is the total number of plant nodes, and P k Let f be the oscillation power amplitude at node k of the power plant. k I is the oscillation frequency of node k in the power plant; k U is the amplitude of the oscillating current at node k of the power plant. k U' is the voltage at node k of the power plant, and U' is the preset converted voltage.

[0019] Among all plant nodes, the plant node whose error between the oscillation frequency and the dominant oscillation frequency is less than a preset error threshold is designated as the oscillation plant node.

[0020] Optionally, the direction of oscillation current flow at each oscillation station node is obtained in the following manner:

[0021] Obtain each branch of each oscillation station node, as well as the oscillation current phase of each branch. When the oscillation current phase of the current branch is greater than 180 degrees, mark the current branch as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, mark the current branch as an inflow branch.

[0022] Obtain the inflow and outflow current of each oscillation station node. If the inflow and outflow current of the current oscillation station node are equal, then the identification of each branch of the current oscillation station node is correct; otherwise, obtain each inflow branch and each outflow branch of the current oscillation station node, and obtain the reference inflow branch in each inflow branch to perform the inflow branch adjustment step.

[0023] The inflow branch adjustment steps are as follows: For each inflow branch, in order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch. Each time an adjustment is made, it is determined whether the inflow current and outflow current of the current oscillation station node are equal. When the inflow current and outflow current of the current oscillation station node are equal, the inflow branch adjustment step ends. After traversing all inflow branches, the inflow branch adjustment step ends.

[0024] When the inflow branch adjustment step is completed, and the inflow current and outflow current of the current oscillating plant node are not equal, obtain the reference outflow branch in each outflow branch and perform the outflow branch adjustment step.

[0025] The outflow branch adjustment steps are as follows: For each outflow branch, in order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current outflow branch is adjusted to an outflow branch. Each time an adjustment is made, it is determined whether the outflow current and the current of the current oscillation station node are equal. When the outflow current and the current of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends.

[0026] Optionally, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude; obtaining the oscillation amplitude of each oscillation station node, and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node includes:

[0027] The propagation direction of the oscillation voltage amplitude of each oscillation station node from largest to smallest is determined as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

[0028] Optionally, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude and the oscillation current amplitude; obtaining the oscillation amplitude of each oscillation station node, and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node includes:

[0029] The oscillation power amplitude P of the branch at the oscillation power plant node is obtained by the following formula. f :

[0030] P f =U f I f cos(θ U -θ I )

[0031] Among them, U f I is the oscillation voltage amplitude of the current branch. f Let θ be the amplitude of the oscillating current in the current branch. U Let θ be the phase of the oscillating voltage of the current branch. I This represents the phase of the oscillating current in the current branch.

[0032] When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source through the current branch out of the oscillation power station node; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation power flow is determined as oscillation flowing into the oscillation power station node through the current branch; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

[0033] Optionally, the step of tracing the oscillation source based on the oscillation propagation direction of each oscillation station node to obtain the oscillation source includes:

[0034] Choose any oscillation station node and perform reverse and forward tracing according to the oscillation propagation direction of each oscillation station node, and record the tracing station node for reverse tracing and the tracing station node for forward tracing.

[0035] Remove the reverse tracing and forward tracing oscillation nodes from each oscillation station node to obtain the untraced oscillation station nodes;

[0036] When the number of untraceable oscillation plant nodes is zero, the last traced reverse tracing plant node in each reverse tracing is taken as the oscillation source.

[0037] When the number of untraceable oscillation power plant nodes is not zero, select any oscillation power plant node from the untraceable oscillation power plant nodes and repeat the above steps.

[0038] A second aspect of the present invention provides a wide-area source tracing system for broadband oscillations in power grids, comprising:

[0039] The data acquisition module is used to acquire oscillation characteristic information of each plant node;

[0040] The oscillating current flow direction analysis module is used to obtain the oscillating plant nodes and the oscillating current flow direction of each oscillating plant node based on the oscillating characteristic quantity information of each plant node.

[0041] The oscillation propagation direction analysis module is used to obtain the oscillation amplitude of each oscillation power plant node. Based on the oscillation amplitude of each oscillation power plant node and the oscillation current flow direction of each oscillation power plant node, the oscillation propagation direction of each oscillation power plant node is obtained.

[0042] The oscillation source tracing module is used to trace the oscillation source based on the oscillation propagation direction of each oscillation station node.

[0043] Optionally, the step of obtaining the oscillating plant nodes among the plant nodes based on the oscillation characteristic information of each plant node includes:

[0044] The dominant oscillation frequency f is obtained through equation (1) or equation (2). main :

[0045]

[0046]

[0047] Where k is the plant node number, n is the total number of plant nodes, and P k Let f be the oscillation power amplitude at node k of the power plant. k I is the oscillation frequency of node k in the power plant; k U is the amplitude of the oscillating current at node k of the power plant. k U' is the voltage at node k of the power plant, and U' is the preset converted voltage.

[0048] Among all plant nodes, the plant node whose error between the oscillation frequency and the dominant oscillation frequency is less than a preset error threshold is designated as the oscillation plant node.

[0049] Optionally, the direction of oscillation current flow at each oscillation station node is obtained in the following manner:

[0050] Obtain each branch of each oscillation station node, as well as the oscillation current phase of each branch. When the oscillation current phase of the current branch is greater than 180 degrees, mark the current branch as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, mark the current branch as an outflow branch.

[0051] Obtain the inflow and outflow current of each oscillation station node. If the inflow and outflow current of the current oscillation station node are equal, then the identification of each branch of the current oscillation station node is correct; otherwise, obtain each inflow branch and each outflow branch of the current oscillation station node, and obtain the reference inflow branch in each inflow branch to perform the inflow branch adjustment step.

[0052] The inflow branch adjustment steps are as follows: For each inflow branch, in order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch. Each time an adjustment is made, it is determined whether the inflow current and outflow current of the current oscillation station node are equal. When the inflow current and outflow current of the current oscillation station node are equal, the inflow branch adjustment step ends. After traversing all inflow branches, the inflow branch adjustment step ends.

[0053] When the inflow branch adjustment step is completed, and the inflow current and outflow current of the current oscillating plant node are not equal, obtain the reference outflow branch in each outflow branch and perform the outflow branch adjustment step.

[0054] The outflow branch adjustment steps are as follows: For each outflow branch, in order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current outflow branch is adjusted to an outflow branch. Each time an adjustment is made, it is determined whether the outflow current and the current of the current oscillation station node are equal. When the outflow current and the current of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends.

[0055] Optionally, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude;

[0056] The oscillation propagation direction analysis module is specifically used to: determine the propagation direction of the oscillation voltage amplitude of each oscillation station node from large to small as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

[0057] Optionally, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude and the oscillation current amplitude;

[0058] The oscillation propagation direction analysis module is specifically used for:

[0059] The oscillation power amplitude P of the branch at the oscillation power plant node is obtained by the following formula. f :

[0060] P f =U f I f cos(θ U -θ I )

[0061] Among them, U f I is the oscillation voltage amplitude of the current branch. f Let θ be the amplitude of the oscillating current in the current branch. U Let θ be the phase of the oscillating voltage of the current branch. I This represents the phase of the oscillating current in the current branch.

[0062] When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source through the current branch out of the oscillation power station node; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation propagation is determined as oscillation flowing from the oscillation source through the current branch into the oscillation power station node; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

[0063] Optionally, the oscillation tracing module is specifically used for:

[0064] Choose any oscillation station node and perform reverse and forward tracing according to the oscillation propagation direction of each oscillation station node, and record the tracing station node for reverse tracing and the tracing station node for forward tracing.

[0065] Remove the reverse tracing and forward tracing oscillation nodes from each oscillation station node to obtain the untraced oscillation station nodes;

[0066] When the number of untraceable oscillation plant nodes is zero, the last traced reverse tracing plant node in each reverse tracing is taken as the oscillation source.

[0067] When the number of untraceable oscillation power plant nodes is not zero, select any oscillation power plant node from the untraceable oscillation power plant nodes and repeat the above steps.

[0068] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the above-described wide-area tracing method for broadband oscillations in power grids.

[0069] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described wide-area tracing method for broadband oscillations in power grids.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] This invention provides a wide-area source tracing method for broadband oscillations in power grids. By analyzing the oscillation characteristic information of each power station node within a wide area, it obtains the oscillating power station node and the direction of oscillation current flow in each oscillating power station node. Then, based on the oscillation amplitude and the direction of oscillation current flow in each oscillating power station node, it obtains the oscillation propagation direction of each oscillating power station node. Based on the oscillation propagation direction of each oscillating power station node, it traces the oscillation source to obtain the oscillation source, achieving accurate analysis of the oscillation propagation path and its impact range. This enables the tracing and accurate location of the oscillation source, providing strong support for power grid operation monitoring and targeted oscillation suppression, effectively supporting dispatching and operation monitoring services, and ensuring the safe operation of the power grid. Attached Figure Description

[0072] Figure 1 This is a flowchart of the wide-area source tracing method for broadband oscillations in power grids according to an embodiment of the present invention.

[0073] Figure 2 This is a schematic diagram of a wide-area monitoring architecture for broadband oscillations in power grids, according to an embodiment of the present invention.

[0074] Figure 3 This is a schematic diagram of wide-area monitoring of power grid broadband oscillations according to an embodiment of the present invention.

[0075] Figure 4 This is a schematic diagram of oscillation propagation under a single branch connection of a power plant node according to an embodiment of the present invention.

[0076] Figure 5 This is a schematic diagram of oscillation propagation under multiple electrical branch connections at a plant node according to an embodiment of the present invention.

[0077] Figure 6 This is a schematic diagram illustrating the forward and reverse tracing of oscillations over a wide area according to an embodiment of the present invention.

[0078] Figure 7 This is a block diagram of the power grid broadband oscillation wide-area tracing system according to an embodiment of the present invention. Detailed Implementation

[0079] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0080] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0081] As introduced in the background section, novel broadband oscillations pose challenges to the safe and stable operation of the current power grid. There is an urgent need to accurately locate the oscillation source and suppress it promptly when it occurs, in order to further reduce the harm caused by oscillations. However, at present, there is considerable research both domestically and internationally on low-frequency oscillations caused by traditional thermal power units, and their oscillation mechanisms are relatively clear. There are also relatively many methods for locating low-frequency oscillation sources, including determining the oscillation source by the phase difference before and after the oscillation starts, and by using transient energy flow methods. These methods are all aimed at traditional electromechanical transient oscillations. However, research on the mechanisms of electromagnetic transient oscillations gradually emerging in the development and construction of new power systems is still in its early stages, and effective technical means for locating their sources are currently lacking.

[0082] In 2015, a large number of subsynchronous / supersynchronous frequency components, including 10Hz, 20Hz, 30Hz, 40Hz, 60Hz, 70Hz, 80Hz, 90Hz, and 110Hz, were detected in a large-scale wind / solar power grid area in a certain region. These components propagated within the renewable energy power plants and across five voltage levels of the power grid, including 35kV, 330kV, and 750kV. Ultimately, this caused three 660MW generators at the Tianzhong DC transmission terminal, more than 300 kilometers away, to trip due to subsynchronous torsional vibration of their shafts. The frequency of the entire Northwest power grid dropped to 49.91Hz, seriously threatening the safe operation of the system. Due to the lack of monitoring methods at the time, the mechanism, propagation path, and analysis and control methods of this event remain unclear. However, it can at least be seen that the new type of electromagnetic transient oscillation has the characteristic of widespread propagation. Therefore, it is necessary to quickly locate the oscillation source and take targeted suppression measures after the oscillation occurs in order to quickly suppress the oscillation.

[0083] Therefore, based on research into oscillation positioning technology within the industry, the following issues need to be addressed:

[0084] 1) Research has only been conducted in the industry on low-frequency oscillation location, and there is a lack of research on the location of sub / supersynchronous oscillation sources, as well as a lack of research on relevant location methods for medium and high frequency oscillation sources generated by the connection of a large number of power electronic devices.

[0085] 2) The dispatching and operation master station lacks wide-area monitoring and source tracing capabilities for broadband oscillations. Although broadband measurement technology has been proposed in the industry to achieve real-time monitoring of broadband oscillations, how to summarize and analyze the oscillation monitoring data from the perspective of dispatching and operation to achieve oscillation source tracing after the oscillation monitoring results are transmitted to the dispatching and operation master station has become an urgent problem to be solved.

[0086] 3) Lack of a wide-area oscillation source tracing method. Broadband oscillations have the characteristic of widespread propagation. Therefore, once an oscillation occurs and propagates, it will affect a series of plants and stations. There is currently no mature method to extract and summarize the oscillation propagation path and accurately trace the source based on the oscillation monitoring information of each plant and station.

[0087] Therefore, in order to effectively address the increasingly serious challenges posed by the development and construction of new power systems, it is urgent to conduct research on wide-area source tracing methods for wide-frequency oscillations, so as to provide strong support for oscillation source localization.

[0088] Based on this, the present invention addresses the above-mentioned problems and proposes an oscillation source tracing method that combines the magnitude of the interharmonic voltage and the direction of the interharmonic current (power) flow based on real-time monitoring data of broadband oscillations. This method can realize a panoramic display of the broadband oscillation propagation path and accurately locate the oscillation source, effectively supporting dispatching and operation monitoring services and ensuring the safety of power grid operation.

[0089] The present invention will now be described in further detail with reference to the accompanying drawings:

[0090] See Figure 1 In one embodiment of the present invention, a wide-area source tracing method for broadband oscillations in power grids is provided, which can effectively achieve accurate location of the oscillation source. Specifically, the broadband oscillation source tracing method for power grids includes the following steps:

[0091] S1: Obtain oscillation characteristic information of each plant node.

[0092] S2: Based on the oscillation characteristic information of each plant node, obtain the oscillating plant node in each plant node, and the direction of oscillation current flow in each oscillating plant node.

[0093] S3: Obtain the oscillation amplitude of each oscillation station node, and obtain the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node.

[0094] S4: Based on the oscillation propagation direction of each oscillation station node, the oscillation source is obtained by oscillation source tracing.

[0095] In summary, the wide-area source tracing method for broadband oscillations in power grids of this invention obtains the oscillating power plant nodes and the oscillating current flow direction of each oscillating power plant node by using the oscillation characteristic information of each power plant node within a wide area. Then, based on the oscillation amplitude and oscillating current flow direction of each oscillating power plant node, the oscillation propagation direction of each oscillating power plant node is obtained. Based on the oscillation propagation direction of each oscillating power plant node, the oscillation source is obtained through oscillation tracing. This enables accurate analysis of the oscillation propagation path and the scope of influence, and achieves the tracing and accurate location of the oscillation source. In turn, it provides strong support for power grid operation monitoring and targeted oscillation suppression, effectively supports dispatching operation monitoring services, and ensures the safe operation of the power grid.

[0096] In one possible implementation, the oscillation characteristic information includes: oscillation frequency and oscillation amplitude and oscillation phase for each oscillation frequency; wherein, the oscillation amplitude includes oscillation power amplitude, oscillation voltage amplitude and oscillation current amplitude; and the oscillation phase includes oscillation voltage phase and oscillation current phase.

[0097] Optional, see Figure 2 and Figure 3 During the synchronization of time among all power plant nodes within the wide area of ​​the power grid, each power plant transmits real-time monitored oscillation characteristic information to the dispatch master station. The oscillation characteristic information includes the oscillation frequency, oscillation amplitude, and oscillation phase information. Among them, the oscillation frequency can include one or more.

[0098] Specifically, for all power plants monitored within the wide area of ​​the dispatch master station, once an oscillation occurs at any power plant, the power plant immediately transmits oscillation characteristic information to the dispatch master station. This includes oscillation alarm information and oscillation characteristic monitoring information. The oscillation characteristic monitoring information mainly focuses on the oscillation frequency, oscillation amplitude, and oscillation phase, specifically divided into voltage and current categories. That is, the frequency, amplitude, and phase of the oscillation current and the frequency, amplitude, and phase of the oscillation voltage. Multiplying the oscillation current and oscillation voltage yields the amplitude of the single-phase oscillation power. Typically, once oscillation occurs, both the voltage and current will exhibit the same oscillation frequency.

[0099] The broadband measurement and processing unit deployed at the plant / station end summarizes the oscillation information from the broadband measurement devices and promptly transmits the oscillation characteristic monitoring information to the dispatch master station, along with oscillation alarm information. After receiving the oscillation alarm information from each plant / station, the dispatch master station identifies these plant / station nodes and can also display the oscillation characteristic monitoring information and oscillation alarm information from each plant / station.

[0100] In one possible implementation, obtaining the oscillating plant node among the plant nodes based on the oscillation characteristic information of each plant node includes: obtaining the dominant oscillation frequency f using equation (1) or equation (2). main :

[0101]

[0102]

[0103] Where k is the plant node number, n is the total number of plant nodes, and P k Let f be the oscillation power amplitude at node k of the power plant. k I is the oscillation frequency of node k in the power plant; k U is the amplitude of the oscillating current at node k of the power plant. k Let U' be the voltage at power plant node k, and U' be the preset converted voltage. Among all power plant nodes, those whose oscillation frequency is less than the preset error threshold are designated as oscillating power plant nodes.

[0104] Specifically, when multiple plants and stations in a wide area trigger oscillation alarm information, at the dispatch master station level, it is necessary to determine the scope and propagation direction of the oscillation from a wide-area perspective.

[0105] The first step is to determine the dominant frequency of the oscillation over a wide area. Since the broadband measurement devices of various power plants may come from different manufacturers and the measurement algorithms used may also differ, when the oscillation involves multiple power plant nodes, it is difficult for the oscillation frequencies measured by each power plant node to be exactly the same. Moreover, as the power grid operating parameters change dynamically, the oscillation frequency will also fluctuate and change. Therefore, it is necessary to be able to uniformly identify the power plant nodes that are actually affected by the oscillation, so as to lay the foundation for oscillation source tracing.

[0106] For each plant node that triggered the oscillation alarm, the oscillation frequencies uploaded by each plant are aggregated according to the whole second, and the dominant oscillation frequency f is determined. main For those satisfying the error threshold f Eror All power plants within the range are identified as oscillation nodes, where, for any oscillation frequency f, f main -f Error ≤f≤f main +f Error They were all considered to be at the same oscillation frequency, and the relevant plant nodes were all determined to be within the range affected by the oscillation propagation.

[0107] Among them, for the dominant oscillation frequency f main Specifically, it can be obtained by analyzing either the oscillation current or the oscillation power.

[0108] (1) Oscillation power mode. The oscillation frequency f transmitted from each plant / station... k With oscillation power P k Multiply the results by adding up the calculation results of all plants and stations to obtain the oscillation power and the dominant oscillation frequency, i.e., the above formula (1).

[0109] (2) Oscillating Current Mode. If multiple power plants have the same voltage level, the oscillation frequency f is directly set to the specified frequency. k With the corresponding oscillation current I k Multiply the results of all the substation calculations and divide by the sum of the oscillation currents to obtain the dominant oscillation frequency. For substations with different voltage levels, the oscillation current method can also be used. It is only necessary to convert the oscillation current under different voltage levels to the same voltage level. That is, multiply the oscillation current of the current voltage level by the current voltage level and then divide by the voltage level to be converted, i.e., the above formula (2). For example, 220kV substations and 110kV substations can be converted to either the high voltage level or the low voltage level. If converted to the high voltage level, the oscillation current of the 110kV substation is multiplied by 110 and then divided by 220. If converted from the high voltage level to the low voltage level, the oscillation current of the 220kV substation is multiplied by 220 and then divided by 110. In general, when converting the current from the high voltage level to the low voltage level, the current will increase. The multiple by which it increases is exactly the ratio of high voltage to low voltage, and vice versa.

[0110] In one possible implementation, the oscillation current flow direction of each oscillation station node is obtained as follows: Each branch of each oscillation station node and its oscillation current phase are acquired. When the oscillation current phase of the current branch is greater than 180 degrees, the current branch is marked as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, the current branch is marked as an inflow branch. The inflow and outflow currents of each oscillation station node are acquired. When the inflow and outflow currents of the current oscillation station node are equal, the identification of each branch of the current oscillation station node is correct; otherwise, each inflow branch and each outflow branch of the current oscillation station node are acquired, and a reference inflow branch is acquired for an inflow branch adjustment step. The inflow branch adjustment step involves: for each inflow branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch. For each branch, the inflow and outflow current of the current oscillation station node are checked for equality. If they are equal, the inflow branch adjustment step ends. After traversing all inflow branches, the inflow branch adjustment step ends. If the inflow branch adjustment step ends and the inflow and outflow currents of the current oscillation station node are not equal, a reference outflow branch is obtained from each outflow branch, and the outflow branch adjustment step is performed. The outflow branch adjustment step involves: for each outflow... For each branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current outflow branch is adjusted to become an outflow branch. Each time an adjustment is made, it is determined whether the outflow current and the reference outflow current of the current oscillation station node are equal. When the outflow current and the reference outflow current of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends.

[0111] Specifically, a preliminary assessment of the inflow and outflow of oscillation current at each oscillation power plant node over a wide area is conducted:

[0112] (1) The oscillation current phase of each oscillation station node is used for judgment. The oscillation current is initially divided according to whether the phase is greater than 180 degrees. The oscillation current less than 180 degrees is initially marked as inflow, and the oscillation current greater than 180 degrees is marked as outflow. The oscillation current initially judged as inflow may be determined as outflow in the final analysis, and vice versa. Therefore, the existing marking is only a preliminary judgment. That is, the oscillation station nodes are initially divided under the premise of following a common principle. The final determination will be made in the subsequent accurate judgment of the flow direction, but it does not affect the result of the whole judgment.

[0113] (2) When a certain oscillating power plant node is connected to multiple other oscillating power plant nodes, the inflow and outflow of the oscillating current of each oscillating power plant node are judged using Kirchhoff's Current Law (KCL). That is, the inflow current into multiple branches of the oscillating power plant node and the outflow current of multiple branches are equal. This relationship is a vector relationship, that is, considering the vector sum of the amplitude and phase of the inflow current of multiple branches of the oscillating power plant node and the vector sum of the amplitude and phase of the outflow current, the amplitudes of the two are the same, the vector directions are opposite and differ by 180 degrees.

[0114] Based on the above preliminary judgment, a secondary analysis and judgment of the inflow and outflow of oscillation current at each oscillation station node within a wide area is conducted:

[0115] (1) Secondary analysis and judgment of inflow branches. When it is found that the vector sum of the inflow and outflow currents of the initially judged oscillating substation node is not equal, it is necessary to re-judge the inflow and outflow directions of each branch, as follows: First, divide the inflow and outflow branches of the oscillating substation node, giving priority to branches of high voltage level, and then considering branches of low voltage level. For one or more branches of high voltage level, the branch with larger amplitude is selected as the reference branch. Then, based on its flow direction, judge the branches with the same flow direction in other prediction results. When the phase difference between the two is greater than 90 degrees, the flow direction of other branches should be adjusted. For example, if a 500kV voltage level branch has the largest amplitude among branches of the same voltage level, it is selected as the reference branch. If the predicted flow direction is inflow, the phase of the inflow current in other branches of other high voltage levels is compared with it. If the phase difference between the current phase of other branches and the current phase of this branch is less than 90 degrees, the original predicted flow direction of the branch is retained; if it is greater than 90 degrees, the flow direction of the branch is adjusted. If the previously predicted direction was inflow, it is adjusted to outflow, and vice versa.

[0116] After each adjustment of the branch current direction, Kirchhoff's Current Law (KCL) is checked again to see if the vector sums of the currents flowing into and out of the branch cancel each other out. That is, the vector sums of the currents flowing into and out of the branch should have equal magnitudes but opposite vector directions, differing by 180 degrees. If the vector sums of the inflow and outflow at the oscillating plant node are not equal after adjustment, the same type of branch is checked again. After checking all inflow branches, if the KCL law is still not satisfied, the outflow branch check is performed until the KCL law is satisfied.

[0117] (2) Secondary determination of outflow direction of node branches. In the outflow branches, a secondary division is first performed based on voltage level. Branches with higher voltage levels are prioritized for analysis and judgment, with the branch with the largest current amplitude among the higher voltage level branches serving as a reference. For example, if there are 5 outflow branches, 2 of which are 220kV and 3 are 110kV, then the 220kV branches form one group, and the 3 110kV branches form another. The 220kV branches are analyzed first, and the branch with the largest current amplitude is selected as the reference branch. The current phase of other branches is compared with the phase of this reference branch. If the phase difference is less than 90 degrees, the original flow direction remains unchanged; otherwise, an adjustment is made, changing the outflow node to an inflow node.

[0118] After each adjustment of the branch current direction, the vector sum of the newly identified inflow and outflow branches of the oscillating substation node is calculated to check if it satisfies KCL's law. If it does, the analysis stops. If not, the analysis continues to the next outflow branch. The analysis proceeds sequentially according to voltage level, and within the same voltage level, the analysis is based on the current amplitude.

[0119] Of course, the reason why the flow direction judgment of the electrical branches connected to the above-mentioned oscillating plant nodes may not satisfy the KCL law is mainly to take into account the phase of the oscillation voltage.

[0120] In one possible implementation, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude; obtaining the oscillation amplitude of each oscillation station node and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude and the oscillation current flow direction of each oscillation station node includes: determining the propagation direction of the oscillation voltage amplitude of each oscillation station node from large to small as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

[0121] Specifically, after the electrical branches connected to the nodes of the oscillating substation have completed the determination of the oscillation current inflow or outflow, it is necessary to analyze the oscillation propagation direction from a wide-area perspective. Although the inflow and outflow directions of the oscillation current at each node of the oscillating substation have been analyzed, it seems that the oscillation propagation direction can be determined by following the path of the oscillation current from the node to the node. However, this still has certain problems. Therefore, relying solely on the oscillation current for analysis and judgment will result in two situations: one is that the direction of the oscillation current inflow and outflow in the analysis is the same as the oscillation propagation direction, and the other is that the direction of the oscillation current inflow and outflow in the analysis is exactly opposite to the oscillation propagation direction. In this case, other criteria are needed for auxiliary judgment.

[0122] In this embodiment, the oscillation voltages at each oscillation station node are first sorted according to their amplitude, because the amplitude of the oscillation voltage at the same oscillation station node is basically the same regardless of its voltage level. Then, the approximate direction of oscillation propagation is determined based on the change in oscillation voltage amplitude, that is, the oscillation voltage propagates from the oscillation station node with a large amplitude to the oscillation station node with a small amplitude. This initial direction of oscillation propagation is then determined in conjunction with the direction of oscillation current inflow and outflow in each electrical branch of the oscillation station node. Specifically, two oscillation station nodes connected by the outflow direction of the oscillation current are selected, and the amplitude of the oscillation voltage at the two oscillation station nodes is judged. If the amplitude of the oscillation voltage decreases, it proves that the original propagation direction judgment is correct, and the judgment of the oscillation propagation direction continues along this path. If the amplitude of the oscillation voltage increases, it proves that the original analysis result is exactly the opposite, and the direction of oscillation current inflow and outflow in each electrical branch of each oscillation station node is adjusted accordingly.

[0123] Analyzing the propagation direction of oscillating voltage does not require analyzing all nodes in the oscillating power plant. It is sufficient to select key nodes for assessment, paying particular attention to those without power supply connections. These nodes are connected only to electrical branches and are not connected to power plants, photovoltaic power stations, or renewable energy plants, nor to series compensation devices such as SVG. This is because these factors can alter the amplitude and phase of individual directly connected nodes, affecting the determination of their propagation direction. Therefore, determining the propagation direction of oscillating voltage requires analyzing the overall trend.

[0124] Select the above-mentioned oscillating power plant nodes without power connection, and arbitrarily select one oscillating power plant node to analyze the trend of oscillation voltage amplitude variation. After completing the analysis of 2 to 3 or more oscillating power plant nodes, if the propagation direction is consistent, it can be used to basically correct the oscillation current flow direction of each oscillating power plant node.

[0125] In one possible implementation, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude and the oscillation current amplitude; obtaining the oscillation amplitude of each oscillation station node, and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node includes: obtaining the oscillation power amplitude P of the branch of the oscillation station node using the following formula. f :

[0126] P f =U f I f cos(θ U -θ I )

[0127] Among them, U f I is the oscillation voltage amplitude of the current branch. f Let θ be the amplitude of the oscillating current in the current branch. U Let θ be the phase of the oscillating voltage of the current branch. I This represents the phase of the oscillating current in the current branch.

[0128] When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source into the oscillation power station node through the current branch; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source out of the oscillation power station node through the current branch; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

[0129] Specifically, 1) Multiply the oscillation current and oscillation voltage of the electrical branches of each oscillation station node to calculate its oscillation power amplitude; 2) If the oscillation power of the branch is positive, it indicates that the oscillation is flowing into the oscillation source; if the oscillation power of the branch is negative, it indicates that the oscillation is flowing out of the oscillation source; 3) Determine the oscillation propagation direction of each oscillation station node by indicating the positive or negative sign of the oscillation power inflow and outflow, and in conjunction with the oscillation current flow direction of each oscillation station node.

[0130] See Figure 4 and Figure 5 The diagrams show the oscillation propagation paths under single-branch connections and multi-branch connections of oscillation plant nodes, respectively. The circles in the diagrams represent oscillation plant nodes.

[0131] In one possible implementation, the step of tracing the oscillation source according to the oscillation propagation direction of each oscillation station node to obtain the oscillation source includes: randomly selecting an oscillation station node, and performing reverse tracing and forward tracing according to the oscillation propagation direction of each oscillation station node, and recording the tracing station nodes traced in reverse tracing and forward tracing; removing the tracing station nodes traced in reverse tracing and forward tracing from each oscillation station node to obtain untraced oscillation station nodes; when the number of untraced oscillation station nodes is zero, taking the last traced reverse tracing station node in each reverse tracing as the oscillation source; when the number of untraced oscillation station nodes is not zero, randomly selecting an oscillation station node from the untraced oscillation station nodes and repeating the above steps.

[0132] Specifically, the oscillation propagation directions of each oscillating substation node within the wide area of ​​the power grid are summarized to form a wide-area oscillation propagation path. The oscillation source is determined by tracing back along this path, and the propagation range is determined by tracing forward, thus forming a complete propagation path. (See [link to documentation]). Figure 6 The circle represents the node of the oscillation power plant, and the specific steps include:

[0133] 1. Reverse tracing. (1) Arbitrarily select a node of an oscillating plant within the oscillation range, and trace back to the previous oscillating plant node one by one according to the direction of oscillation propagation. The previous oscillating plant node is the oscillating plant node from which the oscillating current flows. Continue tracing back in this way until there are no previous oscillating plant nodes. The oscillating plant node finally traced back is the oscillation source. (2) When tracing back to the previous oscillating plant node, if the oscillating plant involves multiple electrical branches, then the multiple electrical branches are traced back in parallel. Each electrical branch is traced back to the previous oscillating plant node until there are no previous oscillating plant nodes. Then, the multiple oscillating plant nodes found after the parallel reverse tracing of each electrical branch are all oscillating sources.

[0134] 2. Forward tracing. (1) After all reverse tracing of any selected oscillation station node has been completed and the oscillation source has been finally determined, the selected oscillation station node is then traced forward along the propagation direction. Forward tracing means tracing along the oscillation propagation direction of the oscillation station node to guide the determination of its propagation boundary. This step is necessary to clarify the complete path of oscillation propagation and its affected range, and to ensure that no omissions occur in the determination of oscillation source. (2) When an oscillation station node involves multiple electrical branch connections, each electrical branch is analyzed in parallel until the boundary of oscillation propagation is found.

[0135] 3. Oscillation Source Summary Analysis. After completing the reverse and forward oscillation tracing, all oscillation plant nodes involved in both analyses are summarized and statistically analyzed. These summaries are then compared with all oscillation plant nodes within the wide-area oscillation monitoring range. If the numbers are the same, the oscillation source analysis is complete. If the numbers are different, the oscillation plant nodes not involved in the forward and forward tracing processes are marked. One oscillation plant node is randomly selected, and forward and forward tracing are performed again to find the oscillation source, until all participating oscillation plant nodes are identical to all oscillation plant nodes within the wide-area oscillation monitoring range.

[0136] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not disclosed in the apparatus embodiments, please refer to the embodiments of the method of the present invention.

[0137] See Figure 7 In another embodiment of the present invention, a wide-area power grid oscillation tracing system is provided, which can be used to implement the above-mentioned wide-area power grid oscillation tracing method. Specifically, the wide-area power grid oscillation tracing system includes a data acquisition module, an oscillation current flow direction analysis module, an oscillation propagation direction analysis module, and an oscillation tracing module.

[0138] The data acquisition module is used to acquire the oscillation characteristic information of each plant node; the oscillation current flow direction analysis module is used to obtain the oscillating plant node and the oscillation current flow direction of each oscillating plant node based on the oscillation characteristic information of each plant node; the oscillation propagation direction analysis module is used to acquire the oscillation amplitude of each oscillating plant node, and obtain the oscillation propagation direction of each oscillating plant node based on the oscillation amplitude and the oscillation current flow direction of each oscillating plant node; the oscillation source tracing module is used to trace the oscillation source based on the oscillation propagation direction of each oscillating plant node.

[0139] In one possible implementation, the oscillation characteristic information includes: oscillation frequency and oscillation amplitude and oscillation phase for each oscillation frequency; wherein, the oscillation amplitude includes oscillation power amplitude, oscillation voltage amplitude and oscillation current amplitude; and the oscillation phase includes oscillation voltage phase and oscillation current phase.

[0140] In one possible implementation, obtaining the oscillating plant node among the plant nodes based on the oscillation characteristic information of each plant node includes: obtaining the dominant oscillation frequency f using equation (1) or equation (2). main :

[0141]

[0142]

[0143] Where k is the plant node number, n is the total number of plant nodes, and P k Let f be the oscillation power amplitude at node k of the power plant. k I is the oscillation frequency of node k in the power plant; k U is the amplitude of the oscillating current at node k of the power plant. k Let U' be the voltage at power plant node k, and U' be the preset converted voltage. Among all power plant nodes, those whose oscillation frequency is less than the preset error threshold are designated as oscillating power plant nodes.

[0144] In one possible implementation, the oscillation current flow direction of each oscillation station node is obtained as follows: Each branch of each oscillation station node and its oscillation current phase are acquired. When the oscillation current phase of the current branch is greater than 180 degrees, the current branch is marked as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, the current branch is marked as an outflow branch. The inflow and outflow currents of each oscillation station node are acquired. When the inflow and outflow currents of the current oscillation station node are equal, the identification of each branch of the current oscillation station node is correct; otherwise, each inflow branch and each outflow branch of the current oscillation station node are acquired, and a reference inflow branch is acquired for an inflow branch adjustment step. The inflow branch adjustment step involves: for each inflow branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch. For each branch, the inflow and outflow current of the current oscillation station node are checked for equality. If they are equal, the inflow branch adjustment step ends. After traversing all inflow branches, the inflow branch adjustment step ends. If the inflow branch adjustment step ends and the inflow and outflow currents of the current oscillation station node are not equal, a reference outflow branch is obtained from each outflow branch, and the outflow branch adjustment step is performed. The outflow branch adjustment step involves: for each outflow... For each branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current outflow branch is adjusted to become an outflow branch. Each time an adjustment is made, it is determined whether the outflow current and the reference outflow current of the current oscillation station node are equal. When the outflow current and the reference outflow current of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends.

[0145] In one possible implementation, the oscillation amplitude of each oscillation station node is the oscillation voltage amplitude; the oscillation propagation direction analysis module is specifically used to: determine the propagation direction of the oscillation voltage amplitude of each oscillation station node from large to small as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

[0146] In one possible implementation, the oscillation amplitude of each oscillation power plant node is the oscillation voltage amplitude and the oscillation current amplitude; the oscillation propagation direction analysis module is specifically used to: obtain the oscillation power amplitude P of the branch of the oscillation power plant node using the following formula. f :

[0147] P f =U f I f cos(θ U -θ I )

[0148] Among them, U f I is the oscillation voltage amplitude of the current branch. f Let θ be the amplitude of the oscillating current in the current branch. U Let θ be the phase of the oscillating voltage of the current branch. I This represents the phase of the oscillating current in the current branch.

[0149] When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source into the oscillation power station node through the current branch; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source out of the oscillation power station node through the current branch; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

[0150] In one possible implementation, the oscillation tracing module is specifically used for: selecting any oscillation station node, and performing reverse and forward tracing according to the oscillation propagation direction of each oscillation station node, and recording the reverse tracing station node and the forward tracing station node; removing the reverse tracing station node and the forward tracing station node from each oscillation station node to obtain untraced oscillation station nodes; when the number of untraced oscillation station nodes is zero, taking the last reverse tracing station node traced in each reverse tracing as the oscillation source; when the number of untraced oscillation station nodes is not zero, selecting any oscillation station node from the untraced oscillation station nodes and repeating the above steps.

[0151] All relevant content regarding the steps involved in the aforementioned embodiments of the wide-area oscillation tracing method for power grids can be referenced from the functional descriptions of the corresponding functional modules in the wide-area oscillation tracing system for power grids in the embodiments of this invention, and will not be repeated here. The module division in the embodiments of this invention is illustrative and is merely a logical functional division; in actual implementation, there may be other division methods. Furthermore, the functional modules in the various embodiments of this invention can be integrated into a processor, exist as separate physical entities, or have two or more modules integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0152] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or 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. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions from the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used for the operation of a wide-area source tracing method for power grid broadband oscillations.

[0153] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the wide-area tracing method for broadband oscillations in the above embodiments.

[0154] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0155] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0156] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0157] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for tracing the source of wide-range oscillations in power grids, characterized in that, include: Obtain oscillation characteristic information of nodes in various power plants and stations within a wide area; Based on the oscillation characteristic information of each plant node, the oscillating plant node in each plant node and the oscillation current flow direction of each oscillating plant node are obtained; including: obtaining the dominant oscillation frequency through equation (1) or equation (2). : （1） （2） in, k Number the plant / station nodes. n This represents the total number of plant nodes. For plant nodes k The amplitude of the oscillation power, For plant nodes k oscillation frequency; For plant nodes k The amplitude of the oscillating current, For plant nodes k voltage, The preset conversion voltage is used; the plant nodes in each plant where the error between the oscillation frequency and the dominant oscillation frequency is less than the preset error threshold are designated as oscillation plant nodes. The direction of oscillation current flow at each oscillation station node is obtained as follows: Each branch of each oscillation station node and its oscillation current phase are acquired. When the oscillation current phase of the current branch is greater than 180 degrees, the current branch is marked as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, the current branch is marked as an inflow branch. The inflow and outflow currents of each oscillation station node are acquired. When the inflow and outflow currents of the current oscillation station node are equal, the identification of each branch of the current oscillation station node is correct; otherwise, each inflow branch and each outflow branch of the current oscillation station node are acquired, and a reference inflow branch is obtained from each inflow branch for inflow branch adjustment. The inflow branch adjustment step is as follows: For each inflow branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch, and each adjustment... Each time, it is determined whether the inflow current and outflow current of the current oscillating power station node are equal. When the inflow current and outflow current of the current oscillating power station node are equal, the inflow branch adjustment step ends; after traversing all inflow branches, the inflow branch adjustment step ends; when the inflow branch adjustment step ends and the inflow current and outflow current of the current oscillating power station node are not equal, the reference outflow branch in each outflow branch is obtained and the outflow branch adjustment step is performed; wherein, the outflow branch adjustment step: for each outflow branch, according to the electrical... The flow direction is maintained when the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees; otherwise, the current outflow branch is adjusted to an inflow branch. Each time an adjustment is made, it is determined whether the inflow and outflow currents of the current oscillation station node are equal. When the inflow and outflow currents of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends. The oscillation amplitude of each oscillation power plant node is obtained. Based on the oscillation amplitude of each oscillation power plant node and the direction of oscillation current flow of each oscillation power plant node, the oscillation propagation direction of each oscillation power plant node is obtained. The oscillation source is obtained by tracing the oscillation propagation direction of each oscillation station node. This includes: selecting any oscillation station node and tracing it backwards and forwards according to the oscillation propagation direction of each oscillation station node, and recording the oscillation station nodes traced in the backward and forward tracing. The oscillation station nodes traced in the backward and forward tracing are removed from each oscillation station node to obtain the untraced oscillation station nodes. When the number of untraced oscillation station nodes is zero, the oscillation station node traced last in each backward tracing is taken as the oscillation source. When the number of untraced oscillation station nodes is not zero, an oscillation station node is selected from the untraced oscillation station nodes and the above steps are repeated.

2. The wide-area source tracing method for broadband oscillations in power grids according to claim 1, characterized in that, The oscillation characteristic information of each plant node is transmitted to the dispatch master station in real time by each plant node; The oscillation characteristic information includes: oscillation frequency, as well as the oscillation amplitude and oscillation phase at each oscillation frequency; The oscillation amplitude includes the oscillation power amplitude, the oscillation voltage amplitude, and the oscillation current amplitude; the oscillation phase includes the oscillation voltage phase and the oscillation current phase.

3. The wide-area source tracing method for broadband oscillations in power grids according to claim 1, characterized in that, The oscillation amplitude of each oscillation station node is the oscillation voltage amplitude; obtaining the oscillation amplitude of each oscillation station node, and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node includes: The propagation direction of the oscillation voltage amplitude of each oscillation station node from largest to smallest is determined as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

4. The wide-area source tracing method for broadband oscillations in power grids according to claim 1, characterized in that, The oscillation amplitude of each oscillation station node is the oscillation voltage amplitude and the oscillation current amplitude; obtaining the oscillation amplitude of each oscillation station node, and determining the oscillation propagation direction of each oscillation station node based on the oscillation amplitude of each oscillation station node and the oscillation current flow direction of each oscillation station node includes: The oscillation power amplitude of the branch at the oscillation power plant node is obtained by the following formula. : in, The amplitude of the oscillation voltage in the current branch. The amplitude of the oscillating current in the current branch. The current branch's oscillating voltage phase, This represents the phase of the oscillating current in the current branch. When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source through the current branch out of the oscillation power station node; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation power flow is determined as oscillation flowing into the oscillation power station node through the current branch; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

5. A wide-area power grid broadband oscillation source tracing system, characterized in that, include: The data acquisition module is used to acquire oscillation characteristic information of each plant node; The oscillation current flow direction analysis module is used to obtain the oscillating plant nodes and the oscillation current flow direction of each oscillating plant node based on the oscillation characteristic quantity information of each plant node; including: obtaining the dominant oscillation frequency through equation (1) or equation (2). : （1） （2） in, k Number the plant / station nodes. n This represents the total number of plant nodes. For plant nodes k The amplitude of the oscillation power, For plant nodes k oscillation frequency; For plant nodes k The amplitude of the oscillating current, For plant nodes k voltage, The preset conversion voltage is used; the plant nodes in each plant where the error between the oscillation frequency and the dominant oscillation frequency is less than the preset error threshold are designated as oscillation plant nodes. The direction of oscillation current flow at each oscillation station node is obtained as follows: Each branch of each oscillation station node and its oscillation current phase are acquired. When the oscillation current phase of the current branch is greater than 180 degrees, the current branch is marked as an outflow branch; when the oscillation current phase of the current branch is less than 180 degrees, the current branch is marked as an inflow branch. The inflow and outflow currents of each oscillation station node are acquired. When the inflow and outflow currents of the current oscillation station node are equal, the identification of each branch of the current oscillation station node is correct; otherwise, each inflow branch and each outflow branch of the current oscillation station node are acquired, and a reference inflow branch is acquired for inflow branch adjustment. The inflow branch adjustment step is as follows: For each inflow branch, following the order of voltage level from high to low and voltage amplitude from high to low at the same voltage level, if the current phase difference between the current inflow branch and the reference inflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current inflow branch is adjusted to an outflow branch, and this adjustment is repeated for each branch. Each time, it is determined whether the inflow current and outflow current of the current oscillating plant node are equal. When the inflow current and outflow current of the current oscillating plant node are equal, the inflow branch adjustment step ends; after traversing all inflow branches, the inflow branch adjustment step ends; when the inflow branch adjustment step ends and the inflow current and outflow current of the current oscillating plant node are not equal, the reference outflow branch in each outflow branch is obtained and the outflow branch adjustment step is performed; wherein, the outflow branch adjustment step: for each outflow branch, according to The order of voltage levels from high to low and voltage amplitudes from high to low at the same voltage level is followed. If the current phase difference between the current outflow branch and the reference outflow branch is less than 90 degrees, the flow direction is retained; otherwise, the current outflow branch is adjusted to an inflow branch. Each time an adjustment is made, it is determined whether the inflow and outflow currents of the current oscillation station node are equal. When the inflow and outflow currents of the current oscillation station node are equal, the outflow branch adjustment step ends. After traversing all outflow branches, the outflow branch adjustment step ends. The oscillation propagation direction analysis module is used to obtain the oscillation amplitude of each oscillation power plant node. Based on the oscillation amplitude of each oscillation power plant node and the oscillation current flow direction of each oscillation power plant node, the oscillation propagation direction of each oscillation power plant node is obtained. The oscillation tracing module is used to trace the oscillation source based on the oscillation propagation direction of each oscillation station node. Specifically, it is used to: randomly select an oscillation station node and perform reverse and forward tracing according to the oscillation propagation direction of each oscillation station node, and record the oscillation station nodes traced in reverse and forward tracing; remove the oscillation station nodes traced in reverse and forward tracing from each oscillation station node to obtain the untraced oscillation station nodes; when the number of untraced oscillation station nodes is zero, take the last traced reverse tracing station node in each reverse tracing as the oscillation source; when the number of untraced oscillation station nodes is not zero, randomly select an oscillation station node from the untraced oscillation station nodes and repeat the above steps.

6. The wide-area power grid oscillation source tracing system according to claim 5, characterized in that, The oscillation amplitude of each oscillation station node is the oscillation voltage amplitude; The oscillation propagation direction analysis module is specifically used to: determine the propagation direction of the oscillation voltage amplitude of each oscillation station node from large to small as the propagation direction from the oscillation source outward; and when the propagation direction from the oscillation source outward is the same as the oscillation current flow direction of each oscillation station node, the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node; otherwise, the opposite direction of the oscillation current flow direction of each oscillation station node is taken as the oscillation propagation direction of each oscillation station node.

7. The wide-area power grid wideband oscillation source tracing system according to claim 5, characterized in that, The oscillation amplitude of each oscillation station node is the oscillation voltage amplitude and the oscillation current amplitude; The oscillation propagation direction analysis module is specifically used for: The oscillation power amplitude of the branch at the oscillation power plant node is obtained by the following formula. : in, The amplitude of the oscillation voltage in the current branch. The amplitude of the oscillating current in the current branch. The current branch's oscillating voltage phase, This represents the phase of the oscillating current in the current branch. When the oscillation power of a branch of an oscillation power station node is positive, the direction of oscillation power flow is determined as oscillation flowing from the oscillation source through the current branch out of the oscillation power station node; when the oscillation power of a branch of an oscillation power station node is negative, the direction of oscillation propagation is determined as oscillation flowing from the oscillation source through the current branch into the oscillation power station node; when the direction of oscillation power flow of at least two oscillation power station nodes is the same as the direction of oscillation current flow, the direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node; otherwise, the opposite direction of oscillation current flow of each oscillation power station node is taken as the direction of oscillation propagation of each oscillation power station node.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the wide-area tracing method for wide-band oscillations of power grids as described in any one of claims 1 to 4.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the wide-area tracing method for broadband oscillations of the power grid as described in any one of claims 1 to 4.

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