A method and system for analyzing three-phase voltage imbalance of a substation bus
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- STATE GRID JIANGXI ELECTRIC POWER CO LTD RES INST
- Filing Date
- 2026-05-29
- Publication Date
- 2026-06-30
Smart Images
Figure CN122307204A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of substation bus voltage analysis technology, and particularly relates to a method and system for analyzing three-phase voltage imbalance of substation bus. Background Technology
[0002] With the large-scale integration of new energy sources and the increasing complexity of power load structures, the three-phase balance of substation bus voltage has become a key indicator for measuring power quality and system safety. Three-phase voltage imbalance not only leads to increased heating and shortened lifespan of power equipment such as transformers and motors, but also causes a series of problems including malfunctions of relay protection devices, increased energy metering errors, and increased line losses, potentially triggering large-scale power outages in severe cases. Therefore, accurate and timely detection and identification of three-phase voltage imbalance is of great significance for ensuring the safe and stable operation of the power system.
[0003] Currently, the main method for detecting three-phase voltage imbalance is based on the symmetrical component method. This method quantifies the imbalance by calculating the ratio of negative-sequence voltage to positive-sequence voltage and sets a fixed threshold (such as 2% as stipulated in the national standard) for judgment. Although this method is simple and intuitive and widely used in engineering practice, it has the following technical drawbacks: First, the symmetrical component method can only output a single overall imbalance value and cannot identify the physical cause of the imbalance. When the system detects an imbalance, maintenance personnel cannot determine whether it is caused by load-side factors (such as single-phase heavy load switching), line parameter factors (such as conductor breakage or insulation aging leading to parameter asymmetry), or system-side factors (such as fault disturbances or harmonic interference). This "knowing what but not why" detection method results in a lack of targeted subsequent remedial measures, often requiring manual on-site investigation, which is time-consuming and labor-intensive.
[0004] Second, traditional methods lack adaptability in threshold setting. Fixed thresholds are difficult to adapt to dynamic changes in system operation and voltage fluctuation ranges under different load conditions. Setting the threshold too high can easily lead to the missed detection of minor imbalances, while setting it too low can easily misjudge normal fluctuations as faults. Especially against the backdrop of high penetration of new energy sources, voltage fluctuations are more frequent and severe, making the limitations of fixed thresholds increasingly apparent.
[0005] Third, traditional methods only utilize voltage amplitude information for imbalance calculation, failing to fully leverage voltage phase angle information. In actual operation, changes in phase angle often reflect early signs of imbalance; for example, in the initial stages of load asymmetry, phase angle shifts may appear before amplitude differences. Ignoring phase angle information results in insufficient sensitivity of traditional methods to early imbalance states, making early warning difficult.
[0006] Fourth, traditional methods struggle to effectively distinguish between transient disturbances and persistent imbalances. Transient events such as lightning strikes and switching operations can cause brief distortions in the voltage waveform, manifested as a short-term increase in the negative sequence component. However, these disturbances typically recover spontaneously within a few cycles and are considered normal system operation phenomena. Traditional methods lack effective discrimination mechanisms, easily misjudging transient disturbances as persistent imbalances, leading to unnecessary alarms and on-site interventions.
[0007] Therefore, how to provide a three-phase voltage imbalance analysis method that can integrate voltage amplitude and phase angle information, has adaptive detection capability, can effectively distinguish between instantaneous disturbances and continuous imbalances, and can accurately identify the physical causes of imbalances has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0008] This invention provides a method and system for analyzing three-phase voltage imbalance in substation busbars to solve the aforementioned technical problems.
[0009] In a first aspect, the present invention provides a method for analyzing three-phase voltage imbalance on a substation busbar, comprising: Acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes the A-phase voltage waveform, the B-phase voltage waveform, and the C-phase voltage waveform; According to the preset data mapping rules, the three-phase voltage waveform data is mapped to a three-dimensional phase space to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. A topology analysis is performed on the voltage phasor trajectory curve to extract the topology feature parameters of the voltage phasor trajectory curve. The topology feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. Based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters, it is determined whether there is a three-phase voltage imbalance state in the bus. If a three-phase voltage imbalance exists, the physical causes of the three-phase voltage imbalance are identified based on the characteristic combination pattern of the topology characteristic parameters. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
[0010] Secondly, the present invention provides a three-phase voltage imbalance analysis system for a substation busbar, comprising: The acquisition module is configured to acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes phase A voltage waveform, phase B voltage waveform and phase C voltage waveform; The mapping module is configured to map the three-phase voltage waveform data to a three-dimensional phase space according to a preset data mapping rule, thereby constructing a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. The extraction module is configured to perform topological structure analysis on the voltage phasor trajectory curve and extract the topological feature parameters of the voltage phasor trajectory curve. The topological feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. The judgment module is configured to determine whether there is a three-phase voltage imbalance state in the bus based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters. The identification module is configured to identify the physical causes of the three-phase voltage imbalance based on the characteristic combination pattern of the topology characteristic parameters if a three-phase voltage imbalance exists. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
[0011] Thirdly, an electronic device is provided, comprising: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the substation bus voltage three-phase imbalance analysis method according to any embodiment of the present invention.
[0012] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the steps of the substation bus voltage three-phase imbalance analysis method according to any embodiment of the present invention.
[0013] The voltage three-phase imbalance analysis method and system for substation busbars disclosed in this application fuses and maps the three-phase voltage amplitude and phase angle information to a three-dimensional phase space to construct voltage phasor trajectory curves. This transforms the voltage imbalance problem into a spatial curve morphology problem, achieving a unified representation of amplitude and phase angle information. Furthermore, topological analysis is performed on the trajectory curves to extract topological characteristic parameters such as the number of connected components, loops, and branch points. These parameters correspond to different imbalance manifestations—connectivity anomalies reflect amplitude deviation, circulation anomalies reflect phase shift, and bifurcation anomalies reflect transient disturbances. Then, by comparing the differences with standard equilibrium state topological characteristic parameters, dynamic and adaptive detection of the imbalance state is achieved, effectively overcoming the limitations of fixed thresholds. Finally, based on the combination patterns of anomaly types, the physical causes of the imbalance are accurately identified—load asymmetry manifests as connectivity anomalies, line parameter asymmetry manifests as a combination of circulation anomalies and bifurcation anomalies, and system-side disturbances manifest as bifurcation anomalies. This method breaks through the limitation of the traditional symmetric component method, which can only calculate the numerical value of the imbalance. It realizes the accurate tracing of the physical causes of imbalance and differentiated management, providing a reliable basis for operation and maintenance personnel to formulate targeted management measures. Attached Figure Description
[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0015] Figure 1 A flowchart of a method for analyzing three-phase voltage imbalance on a substation busbar, provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of a three-phase voltage imbalance analysis system for a substation busbar, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Please see Figure 1The diagram shows a flowchart of a three-phase voltage imbalance analysis method for a substation busbar according to this application.
[0018] like Figure 1 As shown, the method for analyzing the three-phase voltage imbalance of a substation busbar specifically includes the following steps: Step S101: Obtain the three-phase voltage waveform data of the substation bus within a continuous time window. The three-phase voltage waveform data includes the A-phase voltage waveform, the B-phase voltage waveform, and the C-phase voltage waveform.
[0019] Step S102: According to the preset data mapping rules, the three-phase voltage waveform data is mapped to a three-dimensional phase space to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively.
[0020] In this step, the voltage amplitudes of phase A, phase B, and phase C at the same time point are treated as a three-dimensional spatial point, and the three-dimensional spatial points at each time point are connected in chronological order to form the initial voltage phasor trajectory curve. Obtain the voltage phase angle information corresponding to the three-phase voltage waveform data. For each sampling time, convert the voltage phase angle at the sampling time into a phase weighting factor, wherein the phase weighting factor is proportional to the sine or cosine value of the phase angle. The phase weighting factors are superimposed onto the voltage amplitudes of phase A, phase B, and phase C at the corresponding sampling times to obtain the corrected three-dimensional spatial point coordinates. By connecting the corrected three-dimensional spatial points at each time point in chronological order, a voltage phasor trajectory curve that preserves the coupling relationship between voltage amplitude and phase is obtained.
[0021] In one specific embodiment, the three-phase voltage waveform data is converted from a time-domain representation to a geometric representation in a three-dimensional phase space, so that the voltage amplitude information and phase angle information are fused into spatial location information, laying the foundation for subsequent topology analysis.
[0022] First, the voltage amplitudes of phase A, phase B, and phase C at the same time point are considered as a three-dimensional spatial point with coordinates as follows: Connecting the three-dimensional spatial points at each time point in chronological order forms the initial voltage phasor trajectory curve. This initial trajectory curve only reflects the relationship between the three-phase voltage amplitudes and does not yet include phase angle information.
[0023] To incorporate phase angle information into the trajectory curve, the voltage phase angle information corresponding to the three-phase voltage waveform data is obtained. For each sampling moment, the voltage phase angle at that moment is extracted using Hilbert transform or Fourier analysis. The phase angle is converted into a phase weighting factor, which is proportional to the sine or cosine of the phase angle. Specifically, the phase weighting factor can be chosen as... or Alternatively, a weighted combination of the two can be used.
[0024] The phase weighting factors are superimposed onto the voltage amplitudes of phase A, phase B, and phase C at the corresponding sampling times to obtain the corrected three-dimensional spatial point coordinates. The correction rules are as follows: , , , in, This is a preset scaling factor used to control the contribution of phase angle information to spatial position. The value of can be determined according to the voltage level and sampling accuracy, and is generally taken as 1% to 5% of the rated voltage. Through this superposition method, the sampling point with a larger phase shift is further away from the original position in three-dimensional space, thus expressing the coupling relationship between voltage amplitude and phase angle in the form of spatial position change.
[0025] In a specific application scenario, under normal operating conditions, the three-phase voltage amplitude of a 110kV substation busbar is 110kV, with phase angles of 0°, -120°, and 120°, respectively. When load asymmetry occurs, the voltage of phase A drops to 108kV, and the phase angle of phase A shifts to -5°. Calculate the phase weighting factor. Take the proportionality coefficient Then the coordinates of phase A after correction are =108 + 1 × (−0.087) = 107.913 kV. Since the phase angles of phases B and C did not change significantly, their coordinates remained essentially unchanged after correction. Therefore, the position of phase A voltage in three-dimensional space shifted towards the negative direction of the coordinate axes, translating the change in phase angle into a spatial position shift.
[0026] Connecting the corrected three-dimensional spatial points at each time point in chronological order yields a voltage phasor trajectory curve that preserves the coupling relationship between voltage amplitude and phase. The shape of this trajectory curve in three-dimensional space comprehensively reflects the amplitude and phase relationships of the three-phase voltages: when the three-phase voltages are perfectly balanced, the trajectory curve is a straight line passing through the origin; when there is load asymmetry, the trajectory curve deviates towards a certain phase coordinate axis; when there is line parameter asymmetry, the trajectory curve exhibits distortion and bending; when there is system-side disturbance, the trajectory curve exhibits local jitter and branching.
[0027] This step converts the phase angle into a spatial offset and superimposes it onto the amplitude coordinates, so that the position of the three-dimensional spatial point simultaneously reflects the amplitude and phase changes, thus achieving a complete representation of voltage information.
[0028] Step S103: Perform topological analysis on the voltage phasor trajectory curve and extract the topological feature parameters of the voltage phasor trajectory curve. The topological feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve.
[0029] In this step, the voltage phasor trajectory curve is discretized into a point set consisting of multiple trajectory points, and the trajectory points at adjacent time nodes are connected by edges according to the temporal adjacency of the trajectory points to construct a one-dimensional skeleton structure of the trajectory curve. The one-dimensional skeleton structure is traversed using a depth-first traversal algorithm. During the traversal, the visit status of each trajectory point is marked. When a visited trajectory point that is not the predecessor of the current path can be reached from the current trajectory point, it is determined that there is a closed loop. The trajectory point sequence of the closed loop is recorded. The closed loop is removed from the skeleton structure and the traversal continues. The number of all closed loops is counted as the number of loops. After removing all closed loops from the one-dimensional skeleton structure, a depth-first traversal is performed again on the remaining skeleton structure, and the number of connected segments formed during the traversal is counted as the number of connected components. During the traversal, the number of trajectory points connecting three or more edges is counted as the number of branch points.
[0030] In one specific embodiment, the voltage phasor trajectory curve in three-dimensional space is transformed into a one-dimensional skeleton structure in graph theory. A depth-first traversal algorithm is used to extract topological feature parameters reflecting the shape of the trajectory curve, including the number of connected components, loops, and branches. These topological feature parameters characterize the morphological features of the voltage phasor trajectory curve from different dimensions and have a clear correspondence with the physical causes of three-phase voltage imbalance.
[0031] First, the voltage phasor trajectory curve is discretized into a set of points consisting of multiple trajectory points. Each trajectory point corresponds to a three-dimensional spatial coordinate at a sampling time. Since the sampling frequency is fixed and the time intervals between trajectory points are equal, trajectory points at adjacent time nodes are temporally adjacent. Based on the temporal adjacency of the trajectory points, the trajectory points at adjacent time nodes are connected by edges to construct a one-dimensional skeleton structure of the trajectory curve. This one-dimensional skeleton structure is an undirected graph, where nodes are trajectory points and edges represent the temporal connections between trajectory points.
[0032] Next, a depth-first search algorithm is used to traverse the one-dimensional skeleton structure and extract the number of cycles. The specific process of the depth-first search is as follows: Initialize the visit status of all trajectory points to "unvisited". Starting from any unvisited trajectory point, mark it as "currently being visited" and recursively traverse adjacent trajectory points along the edges connected to that point. During the traversal, maintain a stack of the current traversal path, recording all trajectory points on the path from the starting point to the current point.
[0033] When starting from the current trajectory point and moving along an edge to another trajectory point, check the visit status of that target trajectory point: If the target trajectory point is "unvisited", mark it as "being visited", push it onto the path stack, and continue the recursive traversal.
[0034] If the target trajectory point is "being visited" and it is not the direct predecessor of the current trajectory point (i.e., a node before the current trajectory point in the path stack), then a closed loop is found. Record the sequence of trajectory points contained in the closed loop (the path from the target trajectory point to the current trajectory point), and remove the closed loop from the one-dimensional skeleton structure (i.e., mark all edges and nodes on the loop as processed).
[0035] After traversing all points, repeat the process starting from the next unvisited point until all points have been visited. Count the number of all discovered closed loops as the loop count.
[0036] In a specific application scenario, when the voltage phasor trajectory curve exhibits distortion and bending, closed loops will appear in the one-dimensional skeleton structure. For example, asymmetric line parameters can cause phase shifts in the voltage waveform, resulting in a loop-like structure in the trajectory curve in three-dimensional space. This closed loop can be detected through depth-first traversal, and the loop number is recorded as 1 or 2.
[0037] After counting the number of loops, the one-dimensional skeleton structure is simplified. After removing the identified closed loops from the skeleton structure, the remaining skeleton structure no longer contains closed loops and consists only of several connected tree-like structures.
[0038] Next, count the number of connected components. Then, perform a depth-first traversal on the remaining skeleton structure again. The specific process is as follows: Initialize the visit status of all remaining trajectory points to "unvisited". Starting from any unvisited trajectory point, perform a depth-first traversal, marking all trajectory points visited during this traversal; these trajectory points form a connected segment. Increment the count of the connected segments formed in this traversal by 1. Continue the above process starting from the next unvisited trajectory point until all remaining trajectory points have been visited. Count the total number of connected segments as the number of connected components.
[0039] When load asymmetry occurs, the voltage phasor trajectory curve deviates from a straight line in space, forming a spatial curve offset towards a certain phase coordinate axis. Its one-dimensional skeleton structure may split into multiple independent connected segments. For example, when the voltage of phase A drops significantly, the trajectory curve may split into three connected segments: one corresponding to the region where the voltage of phase A is low, and the other two corresponding to the regions where the voltages of phases B and C are normal. At this time, the number of connected components increases from 1 in the standard equilibrium state to 3.
[0040] Finally, count the number of branch points. During the depth-first traversal, simultaneously count the degree of each trajectory point, i.e., the number of edges connected to that trajectory point. When the degree of a trajectory point is greater than or equal to 3, that trajectory point is marked as a branch point. Count the total number of branch points as the branch point count.
[0041] When a system-side disturbance occurs, a transient disturbance appears in the voltage waveform, causing local jitter and bifurcation in the voltage phasor trajectory curve. Near the jitter point, the trajectory curve will develop a branching structure, meaning that a trajectory point connects to three or more edges, forming a branch point. At this time, the number of branch points increases from 0 in the standard equilibrium state to 1 or 2.
[0042] In summary, when the three-phase voltages are perfectly balanced, the trajectory curve is a single straight line without branches or loops, with 1 connected component, 0 loops, and 0 branch points. When load asymmetry occurs, the trajectory curve splits into multiple connected segments, increasing the number of connected components. When line parameter asymmetry occurs, the trajectory curve becomes distorted and bent, forming closed loops and branch points, increasing the number of loops and branch points. When system-side disturbances occur, the trajectory curve exhibits localized jitter, forming isolated branch points, increasing the number of branch points. This mapping relationship makes the identification of the physical causes of imbalance readily interpretable.
[0043] Step S104: Based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters, determine whether there is a three-phase voltage imbalance state in the bus.
[0044] In this step, historical three-phase voltage waveform data of the bus under historical normal operating conditions are obtained, and standard equilibrium state topology characteristic parameters corresponding to the historical three-phase voltage waveform data are extracted. The standard equilibrium state topology characteristic parameters include the number of standard connected components, the number of standard loops, and the number of standard branch points. Calculate the difference between the number of connected components and the standard number of connected components. If the difference is greater than a preset first difference threshold, it is determined that there is a connectivity anomaly. Calculate the difference between the number of loops and the standard number of loops. If the difference is greater than the preset second difference threshold, it is determined that there is an abnormality in circulation. Calculate the difference between the number of branch points and the standard number of branch points. If the difference is greater than the preset third difference threshold, it is determined that there is a bifurcation anomaly. When at least one of the following is determined to be present: connectivity anomaly, circulation anomaly, or bifurcation anomaly, the busbar is determined to have a three-phase voltage imbalance.
[0045] In one specific embodiment, the currently extracted topology feature parameters are compared with the standard balanced state topology feature parameters of the bus under historical normal operation. The difference is used to determine whether there is an anomaly, and the anomaly type is used to comprehensively determine whether there is a three-phase voltage imbalance.
[0046] First, historical three-phase voltage waveform data of the busbar under normal operating conditions were obtained. The selection of historical data followed these principles: at least 30 consecutive normal operating days were selected, and multiple stable operating periods were selected for each operating day (such as the early morning low load period, the midday stable period, etc.), with each period lasting 10 power frequency cycles. The three-phase voltage waveform data of these normal operating periods were used as the historical sample library.
[0047] For each historical sample, the number of connected components, loops, and branches are extracted according to the methods described in steps S101 to S103. Since the bus voltage is in a balanced state during normal operation, the topological characteristic parameters of these samples should exhibit a stable statistical distribution. The median of the number of connected components for all historical samples is calculated as the standard number of connected components, the median of the number of loops is calculated as the standard number of loops, and the median of the number of branches is calculated as the standard number of branches. In a typical normal bus operation scenario, the standard number of connected components is 1, the standard number of loops is 0, and the standard number of branches is 0.
[0048] Next, calculate the difference ΔC = C between the current number of connected components and the standard number of connected components. current -C standard If ΔC > 0, it indicates that the current trajectory curve has split, with multiple separate connected segments. The preset first difference threshold is 0, meaning that as long as the number of connected components increases, a connectivity anomaly is determined. This is because under normal operating conditions, the voltage phasor trajectory curve is a continuous spatial curve with a constant number of connected components (1). Once an amplitude deviation occurs, the trajectory curve splits into multiple connected segments, increasing the number of connected components. Therefore, a connectivity anomaly reflects a sustained amplitude deviation in one or two phases of the three-phase voltage.
[0049] Calculate the difference between the current number of loops and the standard number of loops, ΔL = L. current -L standardIf ΔL > 0, it indicates that a closed loop has appeared in the current trajectory curve. The preset second difference threshold is 0, meaning that as long as the number of loops increases, a circulating current anomaly is determined to exist. This is because under normal operating conditions, the voltage phasor trajectory curve is a simple curve without loops; once phase shift or waveform distortion occurs, the trajectory curve will be twisted and bent, forming a closed loop. Therefore, a circulating current anomaly reflects that there is a phase shift or waveform distortion between the three-phase voltages.
[0050] Calculate the difference between the current number of branch points and the standard number of branch points, ΔB = B. current -B standard If ΔB > 0, it indicates that a branching structure has appeared in the current trajectory curve. The preset third difference threshold is 0, meaning that as long as the number of branch points increases, a bifurcation anomaly is determined to exist. This is because under normal operating conditions, the voltage phasor trajectory curve is a smooth curve without branch points; once transient disturbances or harmonic interference occur, the trajectory curve will produce local jitter, forming a branching structure. Therefore, a bifurcation anomaly reflects the presence of transient disturbances or harmonic interference in the voltage waveform.
[0051] A three-phase voltage imbalance is determined to exist on the busbar if at least one of the following anomalies is identified: connectivity anomaly, circulation anomaly, or bifurcation anomaly. If none of the three anomalies are present, the busbar voltage is determined to be in a balanced state.
[0052] In a specific application scenario, under normal operating conditions, the standard number of connected components is 1, the standard number of loops is 0, and the standard number of branch points is 0. The currently extracted topology feature parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 0. The differences between the three parameters are all 0, and none of them exceed the preset threshold. Therefore, it is determined that there is no three-phase voltage imbalance on the bus.
[0053] In another specific application scenario, the load on phase A of the substation bus suddenly increased. The currently extracted topological feature parameters are: number of connected components = 3, number of loops = 0, and number of branch points = 0. The calculated differences are: ΔC = 2 > 0, indicating a connectivity anomaly; ΔL = 0, indicating no circulation anomaly; ΔB = 0, indicating no branching anomaly. Due to the connectivity anomaly, it is determined that the bus has a three-phase voltage imbalance, initially identified as being caused by load asymmetry.
[0054] In another specific application scenario, a line parameter asymmetry fault occurred on the substation bus. The currently extracted topology feature parameters are: number of connected components = 1, number of loops = 1, and number of branch points = 2. The calculated differences are: ΔC = 0, no connectivity anomaly; ΔL = 1 > 0, indicating a circulating current anomaly; ΔB = 2 > 0, indicating a bifurcation anomaly. Due to the presence of both circulating current and bifurcation anomalies, it is determined that the bus has a three-phase voltage imbalance, initially identified as being caused by line parameter asymmetry.
[0055] In another specific application scenario, the substation busbar was subjected to lightning strike disturbance. The currently extracted topological feature parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 1. The calculated differences are: ΔC = 0, indicating no connectivity anomaly; ΔL = 0, indicating no circulating current anomaly; ΔB = 1 > 0, indicating a bifurcation anomaly. Due to the presence of the bifurcation anomaly, it is determined that the busbar has a three-phase voltage imbalance, initially identified as being caused by system-side disturbance.
[0056] Step S105: If a three-phase voltage imbalance exists, the physical causes of the three-phase voltage imbalance are identified based on the characteristic combination pattern of the topology characteristic parameters. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
[0057] In this step, if only connectivity anomalies exist, the physical cause is identified as load asymmetry; If both circulation anomalies and bifurcation anomalies exist simultaneously, the physical cause is identified as asymmetry in line parameters. If only bifurcation anomalies exist, the physical cause is identified as a system-side disturbance; If both connectivity anomalies and circulation anomalies exist simultaneously, the ratio of the severity of the connectivity anomaly to the severity of the circulation anomaly is calculated. If the ratio is greater than a preset ratio threshold, it is identified as load asymmetry dominating; otherwise, it is identified as line parameter asymmetry dominating.
[0058] In one specific embodiment, based on the detection results of connectivity anomalies, circulation anomalies, and bifurcation anomalies determined in step S104, a feature combination pattern recognition method is used to accurately locate the physical cause of the three-phase voltage imbalance. Different anomaly combination patterns correspond to different physical causes, and this correspondence has clear physical interpretability.
[0059] First, obtain the results of the anomaly type determined in step S104, including whether connectivity anomaly exists, whether circulation anomaly exists, and whether bifurcation anomaly exists.
[0060] The first scenario: If only connectivity anomalies exist, while circulation anomalies and bifurcation anomalies do not exist. In this case, the extracted topological feature parameters are as follows: the number of connected components is greater than the standard value (usually the standard value is 1), the number of loops is equal to the standard value (usually 0), and the number of branch points is equal to the standard value (usually 0). This indicates that the voltage phasor trajectory curve has split, forming multiple mutually separated connected segments, but the trajectory curve itself does not show any twisting, bending, or branching structures.
[0061] The physical cause was identified as load asymmetry. This is because load asymmetry mainly manifests as excessive load on one or two phases, leading to a sustained decrease in the voltage amplitude of that phase. In three-dimensional phase space, the coordinate axis direction corresponding to the phase with decreased amplitude will shift, causing the originally continuous spatial curve to split into multiple independent connected segments. For example, when phase A is overloaded, the voltage amplitude of phase A decreases, and the portion of the trajectory curve corresponding to the lower voltage of phase A separates from the portions corresponding to the normal voltage of phases B and C, forming three connected segments.
[0062] Furthermore, based on the position coordinates of each connected segment in three-dimensional space, the phase containing the unbalanced load can be located. The centroid coordinates of each connected segment are calculated; the coordinate axis closer to the centroid indicates the voltage state of the phase primarily corresponding to that segment. The phase corresponding to the connected segment with the largest centroid coordinate offset is determined to be the phase containing the unbalanced load.
[0063] In a specific application scenario, the extracted topological feature parameters of a 110kV substation busbar are: number of connected components = 3, number of loops = 0, and number of branch points = 0. The standard equilibrium parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 0. It was determined that only connectivity anomalies exist. Analysis of the centroid coordinates of each connected segment revealed that the centroid of one segment is close to the A-phase coordinate axis and far from the origin, while the centroids of the other two segments are close to the B-phase and C-phase coordinate axes and close to the origin. Based on this, the physical cause was identified as asymmetrical load on phase A, generating a remedial recommendation: "Phase A load is too heavy; inter-phase load adjustment is recommended."
[0064] The second scenario: If both circulation anomalies and bifurcation anomalies exist simultaneously, while connectivity anomalies are absent. In this case, the extracted topological feature parameters are as follows: the number of loops is greater than the standard value (usually 0), the number of branch points is greater than the standard value (usually 0), and the number of connected components is equal to the standard value (usually 1). This indicates that closed loops and branch points have appeared in the voltage phasor trajectory curve, but the trajectory curve as a whole still remains a connected segment and has not split.
[0065] The physical cause is identified as asymmetric line parameters. This is because asymmetric line parameters (such as broken conductors, aging insulation, loose joints, etc.) can cause a shift in the phase relationship between the three-phase voltages, and may also cause waveform distortion. In three-dimensional phase space, phase shift manifests as twisting and bending of the trajectory curve, forming a closed loop; waveform distortion manifests as local jitter of the trajectory curve, forming branch points. The simultaneous occurrence of loops and branch points is a typical characteristic of asymmetric line parameters.
[0066] Furthermore, based on the distribution of closed loops in three-dimensional space, the phases with parameter asymmetry can be located. The projection direction of each closed loop in three-dimensional space is calculated. When the projection direction is parallel to a certain coordinate axis plane, it indicates that the loop is mainly caused by parameter asymmetry between corresponding phases. For example, if the loops are mainly distributed near the AB phase plane, it is determined that there is parameter asymmetry between the AB phases.
[0067] In a specific application scenario, the extracted topological feature parameters of a substation busbar are: number of connected components = 1, number of loops = 1, and number of branch points = 2. The standard equilibrium parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 0. It is determined that both circulation anomalies and bifurcation anomalies exist simultaneously. Based on the spatial distribution analysis of the closed loops, it was found that the loops are mainly distributed near the AB phase plane. Therefore, the physical cause is identified as an asymmetry in the line parameters between the AB phases, generating a remediation suggestion of "abnormal line parameters between the AB phases, line maintenance recommended."
[0068] The third scenario: If only bifurcation anomalies exist, while connectivity and circulation anomalies are absent. In this case, the extracted topological feature parameters are as follows: the number of branch points is greater than the standard value (usually 0), the number of connected components is equal to the standard value (usually 1), and the number of loops is equal to the standard value (usually 0). This indicates that isolated branch points have appeared in the voltage phasor trajectory curve, but the trajectory curve as a whole remains continuous and has no closed loops.
[0069] The physical cause was identified as a system-side disturbance. This is because system-side disturbances (such as lightning strikes, switching operations, faults, etc.) cause transient interference in the voltage waveform. In three-dimensional phase space, transient interference manifests as local jitter and bifurcation of the trajectory curve, forming isolated branch points. Since the disturbance is instantaneous, it does not cause sustained amplitude deviation or phase shift; therefore, the number of connected components and the number of loops remain unchanged.
[0070] Furthermore, the intensity level of the disturbance can be determined based on the distribution density and range of the branch points. A dense distribution and wide range of branch points indicates a strong disturbance; a sparse distribution and narrow range indicate a weak disturbance. Simultaneously, the direction of the disturbance source can be located based on the clustering areas of the branch points in three-dimensional space.
[0071] In a specific application scenario, a substation busbar is struck by lightning. The currently extracted topology feature parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 3. The standard equilibrium parameters are: number of connected components = 1, number of loops = 0, and number of branch points = 0. It is determined that only a bifurcation anomaly exists. Based on the distribution analysis of the branch points, the three branch points are clustered in a certain area of three-dimensional space with a high distribution density. Therefore, the physical cause is identified as a system-side disturbance, judged to be of moderate intensity, and an alarm signal of "System-side disturbance detected; it is recommended to check the protection operation" is generated.
[0072] The fourth scenario: If both connectivity anomalies and circulation anomalies exist simultaneously. In this case, the extracted topological feature parameters show that the number of connected components and the number of loops are both greater than the standard values. This indicates that the voltage phasor trajectory curve exhibits both splitting and twisting, possibly caused by a combination of factors. Further calculation of the severity ratio is needed to determine the dominant cause.
[0073] Calculate the severity of connectivity anomalies: Sc = ΔC = C current -C standard This refers to the increase in the number of connected components.
[0074] Calculate the severity of the circulation anomaly: Sl = ΔL = L current -L standard That is, the increase in the number of loops.
[0075] Calculate the severity ratio R = Sc / Sl.
[0076] Preset ratio threshold R th It is usually taken as 2. When R > R th When R ≤ R, it indicates that connectivity anomalies are dominant, which is identified as load asymmetry dominating; th When this occurs, it indicates that the circulation anomaly is dominant, which is identified as being dominated by line parameter asymmetry.
[0077] In a specific application scenario, the currently extracted topology feature parameters of a substation bus are: number of connected components = 3, number of loops = 1, and number of branches = 0. The standard equilibrium parameters are: number of connected components = 1, number of loops = 0, and number of branches = 0. Calculate Sc = 2, Sl = 1, and the ratio R = 2. If the preset proportional threshold Rth = 2, then R = Rth, indicating that line parameter asymmetry is dominant. If the preset proportional threshold Rth = 1.5, then R > Rth, indicating that load asymmetry is dominant. The preset proportional threshold can be adjusted according to the actual application scenario and operation and maintenance experience.
[0078] In summary, the steps of this embodiment establish an explicit mapping relationship between combinations of topological characteristic parameters and physical causes. Connectivity anomalies alone correspond to load asymmetry, combinations of circulation anomalies and bifurcation anomalies correspond to line parameter asymmetry, and bifurcation anomalies alone correspond to system-side disturbances. This mapping relationship makes the physical cause identification process highly interpretable, avoids the uncertainties of black-box models, and allows maintenance personnel to directly understand the judgment criteria.
[0079] When multiple anomaly types coexist, the dominant cause can be determined by calculating the severity ratio of connectivity anomalies to circulation anomalies, avoiding misjudgments that may result from simple determinations. This mechanism is particularly important in complex scenarios where multiple faults overlap in real-world power grids.
[0080] For load asymmetry, the phases of unbalanced loads are located by the centroid coordinates of connected segments; for line parameter asymmetry, the phases of lines with asymmetrical parameters are located by the spatial distribution of closed loops; for system-side disturbances, the intensity and direction of disturbances are determined by the distribution density and clustering areas of branch points. This refined location information provides a direct basis for maintenance personnel to formulate targeted mitigation measures.
[0081] Load asymmetry generates load adjustment suggestions, line parameter asymmetry generates line maintenance suggestions, and system-side disturbances generate alarm signals and coordination and mitigation suggestions. This closed-loop process of "identification-location-management" significantly improves operation and maintenance efficiency and the targeted nature of fault handling.
[0082] In summary, the method of this application acquires three-phase voltage waveform data of the bus; maps the three-phase voltage waveform data to a three-dimensional phase space to construct voltage phasor trajectory curves; performs topological structure analysis on the voltage phasor trajectory curves to extract the number of connected components, loops, and branch points; determines whether there is a three-phase voltage imbalance state on the bus based on the difference between the extracted topological characteristic parameters and the standard equilibrium state topological characteristic parameters; if an imbalance state exists, the physical causes are identified based on the characteristic combination patterns of the topological characteristic parameters, including load asymmetry, line parameter asymmetry, and system-side disturbances; by transforming the voltage imbalance problem into topological structure analysis of spatial trajectory curves, accurate identification of the physical causes of the imbalance is achieved, improving the interpretability of the analysis results and providing a reliable basis for targeted remediation.
[0083] Please see Figure 2 The diagram shows a structural block diagram of a three-phase voltage imbalance analysis system for a substation bus according to this application.
[0084] like Figure 2 As shown, the three-phase voltage imbalance analysis system 200 includes an acquisition module 210, a mapping module 220, an extraction module 230, a judgment module 240, and an identification module 250.
[0085] The acquisition module 210 is configured to acquire three-phase voltage waveform data of the substation bus within a continuous time window, the three-phase voltage waveform data including phase A voltage waveform, phase B voltage waveform, and phase C voltage waveform; the mapping module 220 is configured to map the three-phase voltage waveform data to a three-dimensional phase space according to a preset data mapping rule to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the phase A voltage amplitude, phase B voltage amplitude, and phase C voltage amplitude, respectively; the extraction module 230 is configured to perform topological analysis on the voltage phasor trajectory curve to extract the voltage phasor waveform data. The topological characteristic parameters of the voltage phasor trajectory curve include at least the number of connected components, the number of loops, and the number of branch points of the trajectory curve; the judgment module 240 is configured to determine whether there is a three-phase voltage imbalance state on the bus based on the difference between the topological characteristic parameters and the preset standard equilibrium state topological characteristic parameters; the identification module 250 is configured to identify the physical cause of the three-phase voltage imbalance based on the characteristic combination pattern of the topological characteristic parameters if a three-phase voltage imbalance state exists, the physical cause including load asymmetry, line parameter asymmetry, and system-side disturbance.
[0086] It should be understood that Figure 2 The modules and references described in the document Figure 1 The steps described in the text correspond to those in the method described above. Therefore, the operations, features, and corresponding technical effects described above also apply to the method described in the text. Figure 2 The various modules in the document will not be described in detail here.
[0087] In other embodiments, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the three-phase voltage imbalance analysis method for substation busbars in any of the above method embodiments. In one embodiment, the computer-readable storage medium of the present invention stores computer-executable instructions, which are configured as follows: Acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes the A-phase voltage waveform, the B-phase voltage waveform, and the C-phase voltage waveform; According to the preset data mapping rules, the three-phase voltage waveform data is mapped to a three-dimensional phase space to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. A topology analysis is performed on the voltage phasor trajectory curve to extract the topology feature parameters of the voltage phasor trajectory curve. The topology feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. Based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters, it is determined whether there is a three-phase voltage imbalance state in the bus. If a three-phase voltage imbalance exists, the physical causes of the three-phase voltage imbalance are identified based on the characteristic combination pattern of the topology characteristic parameters. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
[0088] Computer-readable storage media may include a stored program area and a stored data area, wherein the stored program area may store an operating system and an application program required for at least one function; the stored data area may store data created based on the use of the substation bus voltage three-phase imbalance analysis system, etc. Furthermore, the computer-readable storage medium may include high-speed random access memory, and may also include memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the computer-readable storage medium may optionally include memory remotely disposed relative to a processor, which can be connected to the substation bus voltage three-phase imbalance analysis system via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.
[0089] Figure 3 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present invention, such as... Figure 3 As shown, the device includes a processor 310 and a memory 320. The electronic device may also include an input device 330 and an output device 340. The processor 310, memory 320, input device 330, and output device 340 can be connected via a bus or other means. Figure 3 Taking a bus connection as an example, the memory 320 is the computer-readable storage medium described above. The processor 310 executes various server functions and data processing by running non-volatile software programs, instructions, and modules stored in the memory 320, thereby implementing the three-phase voltage imbalance analysis method for substation busbars described in the above method embodiment. The input device 330 can receive input digital or character information and generate key signal inputs related to user settings and function control of the substation busbar voltage imbalance analysis system. The output device 340 may include a display screen or other display device.
[0090] The aforementioned electronic device can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.
[0091] In one implementation, the above-described electronic device is applied to a three-phase voltage imbalance analysis system for a substation busbar, serving as a client, and includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to: Acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes the A-phase voltage waveform, the B-phase voltage waveform, and the C-phase voltage waveform; According to the preset data mapping rules, the three-phase voltage waveform data is mapped to a three-dimensional phase space to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. A topology analysis is performed on the voltage phasor trajectory curve to extract the topology feature parameters of the voltage phasor trajectory curve. The topology feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. Based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters, it is determined whether there is a three-phase voltage imbalance state in the bus. If a three-phase voltage imbalance exists, the physical causes of the three-phase voltage imbalance are identified based on the characteristic combination pattern of the topology characteristic parameters. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
[0092] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.
[0093] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for analyzing three-phase voltage imbalance on a substation busbar, characterized in that, include: Acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes the A-phase voltage waveform, the B-phase voltage waveform, and the C-phase voltage waveform; According to the preset data mapping rules, the three-phase voltage waveform data is mapped to a three-dimensional phase space to construct a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. A topology analysis is performed on the voltage phasor trajectory curve to extract the topology feature parameters of the voltage phasor trajectory curve. The topology feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. Based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters, it is determined whether there is a three-phase voltage imbalance state in the bus. If a three-phase voltage imbalance exists, the physical causes of the three-phase voltage imbalance are identified based on the characteristic combination pattern of the topology characteristic parameters. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
2. The method for analyzing three-phase voltage imbalance on a substation busbar according to claim 1, characterized in that, The step of mapping the three-phase voltage waveform data to a three-dimensional phase space according to a preset data mapping rule to construct the voltage phasor trajectory curve includes: The voltage amplitudes of phase A, phase B, and phase C at the same time point are taken as a three-dimensional spatial point, and the three-dimensional spatial points at each time point are connected in chronological order to form the initial voltage phasor trajectory curve. Obtain the voltage phase angle information corresponding to the three-phase voltage waveform data. For each sampling time, convert the voltage phase angle at the sampling time into a phase weighting factor, wherein the phase weighting factor is proportional to the sine or cosine value of the phase angle. The phase weighting factors are superimposed onto the voltage amplitudes of phase A, phase B, and phase C at the corresponding sampling times to obtain the corrected three-dimensional spatial point coordinates. By connecting the corrected three-dimensional spatial points at each time point in chronological order, a voltage phasor trajectory curve that preserves the coupling relationship between voltage amplitude and phase is obtained.
3. The method for analyzing three-phase voltage imbalance on a substation busbar according to claim 1, characterized in that, The topological analysis of the voltage phasor trajectory curve and the extraction of its topological feature parameters include: The voltage phasor trajectory curve is discretized into a set of points consisting of multiple trajectory points, and the trajectory points at adjacent time nodes are connected by edges according to the temporal adjacency of the trajectory points to construct a one-dimensional skeleton structure of the trajectory curve. The one-dimensional skeleton structure is traversed using a depth-first traversal algorithm. During the traversal, the visit status of each trajectory point is marked. When a visited trajectory point that is not the predecessor of the current path can be reached from the current trajectory point, it is determined that there is a closed loop. The trajectory point sequence of the closed loop is recorded. The closed loop is removed from the skeleton structure and the traversal continues. The number of all closed loops is counted as the number of loops. After removing all closed loops from the one-dimensional skeleton structure, a depth-first traversal is performed again on the remaining skeleton structure, and the number of connected segments formed during the traversal is counted as the number of connected components. During the traversal, the number of trajectory points connecting three or more edges is counted as the number of branch points.
4. The method for analyzing three-phase voltage imbalance on a substation busbar according to claim 1, characterized in that, The step of determining whether there is a three-phase voltage imbalance state in the bus based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters includes: Acquire historical three-phase voltage waveform data of the bus under historical normal operating conditions, and extract standard equilibrium state topology characteristic parameters corresponding to the historical three-phase voltage waveform data. The standard equilibrium state topology characteristic parameters include the number of standard connected components, the number of standard loops, and the number of standard branch points. Calculate the difference between the number of connected components and the standard number of connected components. If the difference is greater than a preset first difference threshold, it is determined that there is a connectivity anomaly. Calculate the difference between the number of loops and the standard number of loops. If the difference is greater than the preset second difference threshold, it is determined that there is an abnormality in circulation. Calculate the difference between the number of branch points and the standard number of branch points. If the difference is greater than the preset third difference threshold, it is determined that there is a bifurcation anomaly. When at least one of the following is determined to be present: connectivity anomaly, circulation anomaly, or bifurcation anomaly, the busbar is determined to have a three-phase voltage imbalance.
5. The method for analyzing three-phase voltage imbalance on a substation busbar according to claim 4, characterized in that, The step of identifying the physical causes of three-phase voltage imbalance based on the characteristic combination patterns of the topological characteristic parameters includes: If only connectivity anomalies exist, the physical cause is identified as load asymmetry; If both circulation anomalies and bifurcation anomalies exist simultaneously, the physical cause is identified as asymmetry in line parameters. If only bifurcation anomalies exist, the physical cause is identified as a system-side disturbance; If both connectivity anomalies and circulation anomalies exist simultaneously, the ratio of the severity of the connectivity anomaly to the severity of the circulation anomaly is calculated. If the ratio is greater than a preset ratio threshold, it is identified as load asymmetry dominating; otherwise, it is identified as line parameter asymmetry dominating.
6. A three-phase voltage imbalance analysis system for a substation busbar, characterized in that, include: The acquisition module is configured to acquire three-phase voltage waveform data of the substation bus within a continuous time window, wherein the three-phase voltage waveform data includes phase A voltage waveform, phase B voltage waveform and phase C voltage waveform; The mapping module is configured to map the three-phase voltage waveform data to a three-dimensional phase space according to a preset data mapping rule, thereby constructing a voltage phasor trajectory curve, wherein the three coordinate axes of the three-dimensional phase space correspond to the voltage amplitude of phase A, phase B, and phase C, respectively. The extraction module is configured to perform topological structure analysis on the voltage phasor trajectory curve and extract the topological feature parameters of the voltage phasor trajectory curve. The topological feature parameters include at least the number of connected components of the trajectory curve, the number of loops of the trajectory curve, and the number of branch points of the trajectory curve. The judgment module is configured to determine whether there is a three-phase voltage imbalance state in the bus based on the difference between the topology characteristic parameters and the preset standard equilibrium state topology characteristic parameters. The identification module is configured to identify the physical causes of the three-phase voltage imbalance based on the characteristic combination pattern of the topology characteristic parameters if a three-phase voltage imbalance exists. The physical causes include load asymmetry, line parameter asymmetry, and system-side disturbances.
7. An electronic device, characterized in that, include: At least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 6.
8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the method described in any one of claims 1 to 6.