Power distribution cabinet harmonic suppression method based on multi-source data fusion

Abstract

The invention relates to the technical field of power distribution cabinet internal harmonic control, in particular to a power distribution cabinet harmonic suppression method based on multi-source data fusion. By extracting amplitude and phase information at each harmonic frequency point, branch equivalent admittance is calculated, and an admittance distribution state is formed; judging an abnormal branch with admittance deviation at each frequency point, and establishing a corresponding relation between the adjustable electrical parameters and the admittance deviation; in the operation process of the power distribution cabinet, the admittance distribution state and the abnormal branch set are periodically updated, the equivalent admittance of the target branch is dynamically adjusted according to the corresponding relation, and the distribution of the harmonic current among the branches is changed; through the method, the harmonic peak value and the multi-node superposition effect in the power distribution cabinet can be actively reduced, online operation under the condition of multi-frequency and multi-node load fluctuation is adapted, harmonic flow direction reconstruction is achieved on the premise that complex filtering or hardware devices are not added, and the electric energy quality and the system stability of the power distribution cabinet are improved.

Description

A Harmonic Suppression Method for Distribution Cabinets Based on Multi-Source Data Fusion Technical Field

[0001] This invention relates to the field of harmonic control technology inside distribution cabinets, and more specifically to a method for harmonic suppression in distribution cabinets based on multi-source data fusion. Background Technology

[0002] With the widespread integration of nonlinear loads and distributed power sources into power distribution systems, harmonic problems at the distribution cabinet side are becoming increasingly prominent. To control this issue, existing harmonic suppression methods for distribution cabinets mainly combine filtering devices with control strategies to compensate for and suppress harmonic currents or voltages in the power distribution system. Related technologies typically establish mathematical models based on the power distribution system topology, extract harmonic components of specific frequencies or orders using harmonic detection algorithms, and inject compensation signals into the system using inverters, filters, and other devices to reduce harmonic content. For example, CN119154298A proposes constructing a topology and mathematical model of a distributed power source interface inverter, and combining current control mode and voltage control mode to form a hybrid control strategy to separately control harmonics in different frequency domains, thereby achieving harmonic suppression in the power distribution network. CN117154729A discloses a harmonic suppression method based on a hybrid filter, which, through harmonic detection and frequency division extraction, allocates harmonics of different orders to corresponding filtering units for suppression. CN120474015A compensates for harmonic currents in the grid-connected system by using grid voltage feedforward and an improved integrator structure. In actual operation, the significant time-varying and uncertain nature of the grid structure and load status on the distribution cabinet side, frequent switching of nonlinear loads, changes in the operating status of distributed power sources, and parallel connection of multiple levels of equipment all cause dynamic changes in the equivalent impedance of the distribution system across different frequency bands.

[0003] In this situation, harmonic suppression control strategies based on predetermined models or fixed parameters struggle to reflect the impact of system impedance changes on harmonic propagation characteristics in a timely and accurate manner, leading to discrepancies between the calculated harmonic compensation and the actual required compensation. This discrepancy accumulates further during multi-harmonic frequency band or multi-suppression device operation, easily causing unstable harmonic suppression effects and even a decrease in compensation effectiveness in some frequency bands. Since this problem stems from the dynamic mismatch between the power distribution system's impedance characteristics and the control model, and its formation mechanism is systematic and coupled, it is currently difficult to offset its effects solely through control parameter tuning or limited testing. A harmonic suppression method for distribution cabinets under complex operating environments is lacking. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a harmonic suppression method for power distribution cabinets based on multi-source data fusion. The aim is to proactively reduce the peak harmonic values ​​and multi-node superposition effects within the power distribution cabinet, adapt to online operation under multi-frequency and multi-node load fluctuation conditions, and reconstruct the harmonic flow direction without adding complex filtering or hardware devices, thereby improving the power quality and system stability of the power distribution cabinet.

[0005] To achieve the above technical effects, the present invention adopts the following technical solution: a method for harmonic suppression of a distribution cabinet based on multi-source data fusion, comprising the following steps: Step 1: synchronously acquiring the operating signals of multiple parallel branches in the distribution cabinet, extracting multi-frequency harmonic components from the acquired voltage and current signals of each branch, and obtaining the corresponding branch voltage amplitude and branch current amplitude at each preset harmonic frequency point; Step 2: calculating the equivalent admittance parameters of each branch based on the voltage and current amplitudes of the corresponding branches at each harmonic frequency point, and normalizing the equivalent admittance parameters of different branches at the same harmonic frequency point to form admittance distribution state data of the distribution cabinet at that harmonic frequency point; Step 3: based on the admittance distribution state data, at each harmonic frequency point... Step 4: Compare and determine the equivalent admittance parameters of each branch at the harmonic frequency point to identify abnormal branches whose equivalent admittance deviates from the preset admittance distribution range; Step 5: Determine the configurable electrical units involved in harmonic current conduction in each abnormal branch, and determine the electrical parameter adjustment amount corresponding to the configurable electrical units based on the deviation of the equivalent admittance parameters of each abnormal branch at the corresponding harmonic frequency point; Step 6: Adjust the frequency-related electrical parameters of the configurable electrical units in the abnormal branches according to the parameter configuration instructions to change the equivalent admittance parameters of the abnormal branches at the corresponding harmonic frequency points.

[0006] Preferably, in step 2, the admittance distribution state data of the distribution cabinet at the harmonic frequency point is obtained by constructing the relative structural relationship of the equivalent admittance of the branches. The construction process includes: at the target harmonic frequency point, calculating the equivalent admittance amplitude parameters of each branch based on the voltage harmonic components and current harmonic components of the corresponding branch; arranging the equivalent admittance amplitude parameters of each branch according to a preset sorting rule to form an admittance sequence reflecting the relative magnitude relationship of the branch admittances; calculating the difference parameters between the admittance amplitudes of adjacent branches according to the admittance sequence, and using the difference parameters as the structural characterization quantity of the branch admittance distribution at the target harmonic frequency point; associating the structural characterization quantity with the corresponding harmonic frequency point and branch identifier to form admittance distribution state data describing the relative structural characteristics of the branch admittance of the distribution cabinet at the target harmonic frequency point.

[0007] Preferably, in step 3, the identification of abnormal branches is based on the degree of influence of the branch's equivalent admittance on the stability of the admittance distribution structure at the same harmonic frequency point. The identification process includes: at the target harmonic frequency point, based on the admittance distribution state data formed in step 2, extracting the admittance structure characterization quantity corresponding to each branch to form an admittance structure state set at that harmonic frequency point; for any branch to be determined, without changing the admittance structure characterization quantity of other branches, introducing a pre-set amplitude structural disturbance quantity into the admittance structure characterization quantity of the branch to obtain the corresponding disturbed admittance structure state; based on the admittance structure state before and after the disturbance, calculating the structural influence parameter of the branch to be determined; the structural influence parameter The calculation formula is: in, The target harmonic frequency point; , represents the admittance structure state vector composed of the admittance structure characterization quantities of each branch at the harmonic frequency point; Indicates only for the first The perturbation admittance structure state vector formed after introducing a preset structural perturbation amount into a branch is used to simulate the variable range of the branch admittance under harmonic action. The preset structural perturbation amount does not exceed a preset proportion range of the characteristic quantity of the branch admittance structure. The weighted norm is used to reflect the relative influence weights of different branches in the admittance structure. This parameter is used to represent the disturbance intensity of the target branch admittance change on the overall admittance distribution structure. When the structural influence parameter exceeds the preset admittance structure stability range, the branch to be judged is identified as an abnormal branch that has a dominant influence on the harmonic current distribution at the target harmonic frequency point.

[0008] Preferably, in step 3, when multiple harmonic frequency points exist simultaneously, the identification of abnormal branches is based on the consistency of the admittance structure influence of the branch at different harmonic frequency points. The process includes: for the same branch, obtaining the corresponding structural influence parameters at multiple harmonic frequency points, and combining the structural influence parameters at each harmonic frequency point according to the frequency dimension to form a cross-frequency structural influence feature set for the branch; if the structural influence parameters corresponding to each harmonic frequency point in the cross-frequency structural influence feature set all exceed the admittance structure stability range of the corresponding frequency point, and the variation amplitude of the structural influence parameters in the frequency dimension is within a preset consistency range, then the branch is determined to be a multi-frequency abnormal branch that has a continuous dominant influence on the admittance distribution structure at multiple harmonic frequency points; if only some harmonic frequency points in the cross-frequency structural influence feature set have structural influence parameters that exceed the corresponding admittance structure stability range, or the variation amplitude of the structural influence parameters in the frequency dimension exceeds the consistency range, then the branch is not included in the multi-frequency abnormal branch set.

[0009] Preferably, in step 4, the process of determining the configurable electrical units and corresponding electrical parameter adjustment amounts for abnormal branches includes: within the identified abnormal branches, obtaining the branch connection topology information and electrical parameter information of each electrical unit at the target harmonic frequency point, wherein the electrical parameter information includes at least the nominal reactance value, damping parameter, control interface type, and adjustable parameter range of each electrical unit; based on the branch connection topology information and electrical parameter information, constructing an analytical expression for the equivalent admittance of the abnormal branch at the target harmonic frequency point, and expressing the equivalent admittance of the abnormal branch as a functional combination of the parameters of each electrical unit; in the analytical expression for equivalent admittance, applying a small parameter disturbance of a preset amplitude to each adjustable electrical parameter of each electrical unit within the abnormal branch, and calculating the change in equivalent admittance of the abnormal branch caused by the corresponding parameter disturbance; and comparing the change in equivalent admittance with the target harmonic frequency point. The admittance measurement uncertainty threshold and the admittance modeling error threshold at the target harmonic frequency point are compared. If the equivalent admittance change is greater than both the admittance measurement uncertainty threshold and the admittance modeling error threshold, the corresponding electrical unit is determined as a configurable electrical unit with adjustable equivalent admittance for the abnormal branch at the target harmonic frequency point, and a set of configurable electrical units for the abnormal branch is constructed. In the set of configurable electrical units, based on the ratio of the equivalent admittance change corresponding to each configurable electrical unit to the equivalent admittance deviation of the abnormal branch, the admittance allocation coefficient of each configurable electrical unit is calculated. Based on the admittance allocation coefficient and the equivalent admittance deviation of the abnormal branch at the target harmonic frequency point, the target admittance correction amount corresponding to each configurable electrical unit is determined. Based on the correspondence between the target admittance correction amount and the electrical parameters and admittance of each configurable electrical unit, the electrical parameter adjustment amount of each configurable electrical unit is calculated.

[0010] Preferably, in step 4, when calculating the electrical parameter adjustment amount, cross-frequency constraint processing is performed on the admittance correction requirements of the same abnormal branch at multiple harmonic frequency points. The process includes: for the same abnormal branch, obtaining the target admittance correction amount corresponding to each configurable electrical unit at multiple harmonic frequency points, and arranging the target admittance correction amounts according to the harmonic frequency points to form a multi-frequency admittance correction sequence for the configurable electrical unit; performing sign consistency and amplitude deviation analysis on the multi-frequency admittance correction sequence; if the target admittance correction amounts corresponding to different harmonic frequency points are inconsistent in the sign direction, or their amplitude differences exceed the preset cross-frequency deviation threshold, then the configurable electrical unit is... Electrical units are configured and marked as having cross-frequency admittance correction conflicts. For electrical units marked as having cross-frequency admittance correction conflicts, cross-frequency constraint reshaping is performed on the multi-frequency admittance correction sequence under the condition that the overall equivalent admittance deviation of the constrained abnormal branch does not increase. The cross-frequency constraint reshaping is completed by increasing the constraint priority of the admittance correction amount corresponding to the harmonic frequency point with a high contribution to the admittance deviation of the abnormal branch, and simultaneously compressing the adjustment range of the admittance correction amount corresponding to the other harmonic frequency points. After the cross-frequency constraint reshaping is completed, the effective admittance correction amount of each configurable electrical unit at each harmonic frequency point is output as the constraint input for the calculation process of electrical parameter adjustment amount.

[0011] Preferably, in step 4, during the process of constraining the electrical parameter adjustment amount based on the effective admittance correction amount, continuity and boundary constraints are applied to the admittance change trajectory during the electrical parameter adjustment process to limit the adjustment path. The process includes: obtaining the admittance change trajectory corresponding to the change from the current electrical parameter state to the target electrical parameter state of each configurable electrical unit at each harmonic frequency point, and representing the admittance change trajectory as a discrete admittance sequence that progresses with the parameter change step size; calculating the change amplitude between adjacent admittance states in the discrete admittance sequence segment by segment; if the change amplitude between adjacent admittance states exceeds the preset admittance change upper limit threshold at the corresponding harmonic frequency point, it is determined that the electrical parameter adjustment path has a risk of admittance abrupt change; for the electrical parameter adjustment path determined to have a risk of admittance abrupt change, the parameter change step size is segmented and reconstructed, by reducing the single parameter change amplitude and increasing the number of parameter change segments, so that the change amplitude between adjacent admittance states is limited to the admittance change upper limit threshold; after completing the segmented reconstruction process, a constrained parameter adjustment trajectory is generated based on the reconstructed parameter change step size sequence, and the constrained parameter adjustment trajectory is used as the path constraint for performing electrical parameter adjustment.

[0012] Preferably, in step 5, during the operation of the distribution cabinet, periodic admittance state change triggering conditions are set for steps one to three. The triggering conditions include at least a change in the abnormal branch set or a change in the equivalent admittance parameter of any abnormal branch at the target harmonic frequency point relative to the previous operating cycle exceeding a preset admittance change threshold. Only when the triggering conditions are met is a parameter configuration instruction for the configurable electrical unit generated based on the updated abnormal branch and the corresponding electrical parameter adjustment amount.

[0013] Preferably, in step 6, during parameter adjustment, the parameter adjustment of the same configurable electrical unit at different harmonic frequency points is differentiated by constructing a frequency-related parameter mapping relationship. The process includes: obtaining the equivalent admittance correction requirement of the configurable electrical unit in each abnormal branch at each target harmonic frequency point, and representing the equivalent admittance correction requirement as an admittance target set indexed by harmonic frequency; based on the admittance target set, establishing a frequency-related parameter mapping model for the configurable electrical unit, mapping the admittance target at different harmonic frequency points to the corresponding frequency-related electrical parameter components inside the electrical unit, wherein each parameter component is independent of each other in electrical structure and is not coupled to each other during adjustment; during the parameter configuration instruction execution stage, adjusting each frequency-related electrical parameter component of the configurable electrical unit according to the frequency-related parameter mapping model, so that the electrical unit presents the corresponding equivalent admittance state at each target harmonic frequency point.

[0014] Preferably, in step 6, during the adjustment of frequency-related electrical parameters of the configurable electrical units in the abnormal branch, frequency-layered adjustment timing constraints are used to expand the parameter configuration command. The process includes: prioritizing the frequency-related electrical parameter components based on the equivalent admittance deviation corresponding to each target harmonic frequency point to form a parameter adjustment sequence divided by harmonic frequency level, wherein the parameter component with the lower harmonic frequency has a higher adjustment priority in the parameter adjustment sequence; when executing the parameter adjustment sequence, an independent adjustment step size upper limit and an intermediate stability judgment interval are set for the parameter components of each frequency level; after the adjustment of the parameter components of the current frequency level is completed, it is detected whether the equivalent admittance change of the corresponding abnormal branch at the harmonic frequency point enters the preset stability interval; if the detection result meets the stability interval constraint, the parameter component adjustment of the next frequency level continues; if the stability interval constraint is not met, the parameter components of the current frequency level are backtracked and corrected, and the adjustment process of the frequency level is re-entered after the backtracking correction is completed.

[0015] Based on the above technical solution, the positive and beneficial effects of this invention are as follows: 1. This invention identifies abnormal branches and main harmonic propagation paths by real-time calculation and distribution determination of the equivalent admittance of each branch in the distribution cabinet at different harmonic frequencies, and reconstructs the admittance of abnormal branches through adjustable electrical parameters, thereby realizing the active distribution of harmonic current in the distribution cabinet. This method overcomes the limitations of existing technologies that rely solely on compensation or filter control, and can actively change the flow direction and distribution structure of harmonics before they are amplified or superimposed, fundamentally reducing local harmonic peak values ​​and multi-node superposition effects, and improving power quality.

[0016] 2. This invention introduces a frequency-dependent equivalent admittance adjustment mechanism for abnormal branches, which decomposes the adjustment requirements of the same configurable electrical unit at different harmonic frequency points into mutually independent frequency-dependent electrical parameter components. This breaks through the inherent limitation of existing technologies where a single electrical parameter cannot simultaneously adapt to multiple harmonic frequency points. As a result, in the operating environment of a distribution cabinet where multiple harmonics coexist, harmonic suppression no longer depends on frequency point superposition or multiple device stacking, but rather on the frequency differentiation of the parameter structure within the unit to achieve multi-frequency coordinated control.

[0017] 3. This invention directly acts on the adjustable electrical parameters of existing distribution cabinet branches in terms of control logic, adjusting harmonic currents by changing the equivalent admittance distribution, without the need for complex filtering devices or high-precision modeling systems. Since the operating object is the adjustable parameters of the branch, it can be implemented in existing distribution cabinet structures, offering advantages such as simple implementation, high reliability, and strong scalability, while also considering system robustness and harmonic suppression efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them: Figure 1 is a schematic diagram of the steps of the present invention; Figure 2 is a schematic diagram of the working principle of step 3 of the present invention; Figure 3 is a flowchart of the identification and admittance contribution allocation of the abnormal branch configurable electrical unit of the present invention; Figure 4 is a logic diagram of the multi-frequency constraint and admittance adjustment path generation of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] In a possible implementation, we will use a distribution cabinet in an industrial park's power distribution system as an example. This distribution cabinet serves as a centralized power supply node for various loads within the park. Downstream, it connects to frequency converters, rectifiers, nonlinear electrical equipment, and some new energy interface devices. During long-term operation, it exhibits significant multiple harmonic superposition characteristics. The common problem with this type of distribution cabinet in actual operation is not simply exceeding the amplitude limit of a single harmonic, but rather the dynamic distribution and amplification of harmonic currents across different branches. This leads to severe current distortion in some branches and abnormal heating of components within the cabinet, and this phenomenon changes frequently with variations in load combinations.

[0021] For the above application environment, the power distribution cabinet harmonic suppression method based on multi-source data fusion described in this embodiment does not design the suppression object as the branch electrical structure inside the power distribution cabinet as the overall control object.

[0022] In terms of main hardware structure, this distribution cabinet is similar to existing ones, including a cabinet body, a main incoming line unit, several parallel branch units, and a control and regulation unit located inside the cabinet. Each branch unit corresponds to a different load circuit, and each branch unit is equipped with a circuit breaker, a measuring transformer, and at least one configurable electrical unit in sequence. In specific implementations, the configurable electrical unit can be one or more of a variable reactance module, a variable damping module, or a power injection module with frequency response characteristics. Its structural form can be selected and configured according to engineering conditions, but all have the ability to change their equivalent electrical parameters under the action of control signals.

[0023] Inside the distribution cabinet, measuring transformers are arranged after each branch circuit breaker to collect voltage and current signals for the corresponding branch. All measuring transformers are connected to a data acquisition unit located in the cabinet's control area via shielded signal cables. The data acquisition unit can be an industrial-grade acquisition module, equipped with a synchronous sampling circuit to sample the voltage and current of each branch under a unified time reference.

[0024] The data acquisition unit converts the acquired raw analog signals into digital signals and transmits them to the control processing unit in the power distribution cabinet via an internal bus. This control processing unit can be an industrial controller or an embedded processing module, and it runs software programs internally for executing the method of this invention. Logically, the control processing unit forms a closed-loop connection with the data acquisition unit and each configurable electrical unit, and its output is connected to the configurable electrical units of each branch via a control interface.

[0025] During system operation, the control processing unit first triggers the data acquisition unit to perform synchronous sampling according to a preset sampling period. The sampling period can be set according to the load change rate of the distribution cabinet; for example, a shorter period is used in scenarios with frequent load fluctuations, and a longer period is used in scenarios with relatively stable loads. In this embodiment, the sampling period is not a critical limitation, but only exists as an operating parameter.

[0026] The collected voltage and current data for each branch are first used for harmonic spectrum analysis within the control processing unit. The control processing unit performs frequency domain conversion on the voltage and current signals of each branch, extracting amplitude and phase information at multiple target harmonic frequency points. The target harmonic frequency points can be selected based on power grid standards and field experience, for example, including common harmonic frequencies such as the third, fifth, and seventh harmonics.

[0027] After completing frequency domain analysis, the control processing unit does not directly superimpose or compare harmonic currents, but instead proceeds to the admittance modeling stage. For the same harmonic frequency point, the control processing unit reads the voltage and current amplitudes of each branch at that frequency point, and calculates the equivalent admittance parameter of the corresponding branch through the ratio between the two. This equivalent admittance parameter reflects the conduction characteristics of the branch to the harmonic current at that harmonic frequency point and is the basis for all subsequent judgments and adjustments.

[0028] To eliminate the impact of differences in rated capacity and line length between different branches on the admittance values, the control processing unit normalizes the equivalent admittance parameters of each branch at the same harmonic frequency. The normalization process does not change the relative admittance relationship between branches, but rather maps the admittance parameters to a unified comparison scale, making the admittance distribution of different branches comparable at that frequency. Through this processing, the control processing unit generates a set of admittance distribution data reflecting the admittance structure inside the distribution cabinet at each harmonic frequency.

[0029] In this embodiment, the aforementioned admittance distribution state data is not used merely as an instantaneous result, but rather as a fundamental state variable describing the harmonic propagation structure inside the distribution cabinet, participating in subsequent processing. In subsequent steps, the control processing unit uses this admittance distribution state data to identify abnormal branches, calculate parameter adjustments, and generate configuration instructions.

[0030] After generating admittance distribution data at each harmonic frequency point, the control processing unit identifies abnormal branches. It should be noted that in traditional power distribution systems, harmonic anomalies are typically determined by monitoring whether the harmonic current amplitude exceeds limits. This method assumes that harmonic problems directly correspond to a specific branch or device. However, in distribution cabinets with multiple loads, the actual distribution of harmonic currents is often influenced by the combined admittance characteristics of multiple branches. Simply relying on the magnitude of the harmonic current makes it difficult to accurately identify the branch that dominates the harmonic distribution; this has long been a common technical bias in engineering practice.

[0031] In this embodiment, the control processing unit does not sort or threshold the absolute values ​​of harmonic currents. Instead, it performs a horizontal comparison of the normalized equivalent admittance parameters of each branch at each target harmonic frequency point. Specifically, at the same harmonic frequency point, the control processing unit arranges the normalized admittance parameters of all branches into an admittance distribution sequence and determines an admittance distribution interval based on this sequence. This admittance distribution interval is not a fixed threshold, but a dynamic interval determined by the admittance status of each branch within the current distribution cabinet, and its range can be automatically adjusted according to changes in load combination.

[0032] After the admittance distribution range is determined, the control processing unit checks the normalized admittance parameters of each branch at that harmonic frequency point. When the admittance parameter of a branch deviates from the admittance distribution range and the deviation exceeds the preset structural deviation judgment condition, the control processing unit marks the branch as an abnormal branch at that harmonic frequency point. It is important to emphasize that the determination of an abnormal branch is not based on the maximum or minimum value, but on the degree of its abnormality relative to the overall admittance structure. This degree of abnormality reflects the possibility that the branch will have a nonlinear effect on the harmonic current distribution at the current harmonic frequency point.

[0033] Since multiple target harmonic frequency points typically exist simultaneously in a distribution cabinet, after the control processing unit completes the identification of an abnormal branch at a single frequency point, it will repeat the aforementioned admittance distribution comparison process for other harmonic frequency points. Therefore, each branch may exhibit different states at different harmonic frequency points; a particular branch may only be identified as abnormal at a specific harmonic frequency point, while remaining normal at other frequency points.

[0034] The control processing unit summarizes the abnormal branch results identified at each harmonic frequency point, forming an abnormal branch status set. This set not only records the identification information of the abnormal branch, but also includes the corresponding harmonic frequency point and the admittance deviation information at that frequency point. The admittance deviation describes the degree of deviation of the abnormal branch from the admittance distribution range at that frequency point, and is an important input for subsequent parameter adjustment calculations.

[0035] By adopting the above approach, we can avoid the traditional practice of simply attributing harmonic problems to a certain fixed equipment or a certain fixed branch. Instead, we can establish the identification of abnormal branches on the basis of the overall admittance structure analysis of the distribution cabinet, so that the identification of harmonic propagation paths and dominant branches has a repeatable and verifiable engineering basis.

[0036] After identifying the abnormal branches, the control processing unit analyzes the adjustment targets for each abnormal branch. For each branch marked as abnormal, the control processing unit does not directly apply uniform adjustments to the entire branch, but further analyzes the configurable electrical units within that branch that participate in harmonic conduction. Specifically, the control processing unit first reads the structural configuration parameters of the abnormal branch, including the type, quantity, and connection position of the configurable electrical units within the branch. These structural configuration parameters can be entered by engineers during system deployment or pre-configured through structural mapping from the distribution cabinet design drawings.

[0037] After acquiring the branch structure information, the control processing unit, considering the deviation of the equivalent admittance of the branch at the corresponding harmonic frequency, analyzes each configurable electrical unit along the branch's electrical topology. Specifically, while keeping other unit parameters constant, the sensitivity of each configurable electrical unit's parameter changes to the branch's equivalent admittance is evaluated. This sensitivity reflects the adjustable contribution of the electrical unit to the branch's admittance at the harmonic frequency. The control processing unit then selects configurable electrical units within the branch that significantly contribute to the change in equivalent admittance at the target harmonic frequency and uses these as candidates for subsequent adjustment. This selection process avoids indiscriminate adjustment of all electrical units within the branch, reducing uncertainty during adjustment and minimizing interference with the original power distribution structure.

[0038] For each abnormal branch, the control processing unit reads the equivalent admittance deviation of that branch at the corresponding harmonic frequency point. This admittance deviation reflects the degree of deviation of the current admittance state of the abnormal branch relative to the overall admittance distribution state of the distribution cabinet, and its sign and amplitude correspond to the admittance deviation direction and magnitude, respectively. Based on this admittance deviation, the control processing unit determines the target admittance correction direction and correction amplitude range for the abnormal branch at that harmonic frequency point.

[0039] Based on this, the control processing unit decomposes the target admittance correction requirement into the aforementioned set of configurable electrical units. Specifically, the control processing unit allocates the admittance correction requirement based on the admittance sensitivity characteristics of each configurable electrical unit at the harmonic frequency, allowing different electrical units to undertake different degrees of admittance adjustment tasks. This allocation process is not an equal distribution, but rather a weighted processing based on the response characteristics of each electrical unit to admittance changes, thereby avoiding any single electrical unit bearing excessive parameter changes.

[0040] When multiple harmonic frequencies coexist, a single configurable electrical unit often needs to regulate multiple harmonic frequencies simultaneously. To address this engineering challenge, this embodiment introduces a frequency-related parameter mapping mechanism. The control processing unit does not treat the configurable electrical unit as an object with only a single parameter, but rather abstracts its internal parameter structure into multiple frequency-related parameter components. Each parameter component corresponds to a target harmonic frequency, and each parameter component is logically independent. In implementation, the control processing unit establishes a frequency-related parameter mapping relationship based on the physical characteristics of the configurable electrical unit. For example, for a variable reactance electrical unit, its equivalent reactance change at different frequencies can be frequency-selectively adjusted through an internal control structure; for an electrical unit with damping characteristics, the effect of its damping parameter at different frequencies can also be distinguished through control parameter mapping. This embodiment is not limited to a specific implementation form, as long as the electrical unit can exhibit frequency-related equivalent electrical parameters under the action of the control signal.

[0041] In one possible implementation, configurable electrical units are installed on the incoming side or branch nodes of each parallel branch in the distribution cabinet. These units include at least one set of series adjustable reactor units and one set of parallel damping adjustment units. The series adjustable reactor units are composed of controllable reactors or equivalent adjustable inductance branches made of power electronic devices. Their equivalent inductance value changes under control commands, thereby altering the inductive reactance of the branch at the target harmonic frequency. When the system determines that the equivalent admittance of a branch at the target harmonic frequency is too large, the equivalent inductance value of the series adjustable reactor unit is increased, causing the branch to exhibit a larger inductive reactance at the harmonic frequency, thereby reducing the proportion of harmonic current distribution in the branch. Meanwhile, the parallel damping adjustment unit consists of a damping branch formed by a series resistor and a switching device. The participation level of the damping branch is adjusted by the conduction state of the switching device. When the damping branch is connected, the equivalent resistance component of the branch at the target harmonic frequency is increased, thereby enhancing the energy dissipation characteristics of the harmonic current in the branch. By controlling the combination of the series adjustable reactor unit and the parallel damping adjustment unit, the amplitude and phase characteristics of the equivalent impedance of the target branch at the target harmonic frequency change, thereby breaking the original distribution balance of the harmonic current between the target branch and other branches, causing the harmonic current to naturally shift to other parallel branches with lower equivalent impedance or different damping characteristics. During the adjustment process, the system limits the adjustment range of the adjustable reactor unit and the damping branch to a range that does not affect the fundamental operating parameters, and dynamically maintains or removes the adjustment state of the damping branch and the reactor based on the real-time monitored changes in the harmonic current.

[0042] After completing the frequency-related parameter mapping, the control processing unit converts the target admittance correction requirements at each harmonic frequency point into corresponding parameter component adjustment values, forming a parameter configuration instruction. This parameter configuration instruction logically contains multiple frequency levels, each level corresponding to a harmonic frequency point and its corresponding parameter component adjustment information.

[0043] When executing parameter configuration commands, the control processing unit does not adjust the parameter components of all frequency levels simultaneously, but instead introduces a hierarchical adjustment timing mechanism. Specifically, the control processing unit unfolds the adjustment process according to the preset harmonic frequency level order, prioritizing the adjustment of the parameter components corresponding to low-frequency harmonics. After completing the parameter adjustment of that level, it detects the change in equivalent admittance of abnormal branches at that frequency point.

[0044] If the detection results indicate that the admittance state of the abnormal branch at the harmonic frequency has entered the preset stable range, the control processing unit continues to execute parameter adjustment at the next frequency level; if it has not entered the stable range, the parameter adjustment process at the current level is corrected or rolled back until the stable condition is met before proceeding to the next level. In this way, the parameter adjustment process at different frequencies is decoupled and unfolded, avoiding abrupt changes in admittance structure caused by simultaneous changes in multiple frequency parameters.

[0045] It is particularly important to note that these adjustments are gradual and reversible. First, they adjust the performance at specific harmonic frequencies, not to disrupt the fundamental frequency operating conditions. Second, all adjustments have boundary limitations and are only performed within the equipment's permissible operating range. Finally, the system is continuously monitored; if an adjustment causes other indicators to become abnormal, it will automatically correct in the next cycle. Therefore, this invention does not require limitations on how to establish relationships or how to adjust them; essentially, continuous micro-perturbations are sufficient to find the mapping parameters in subsequent cycles.

[0046] Through the aforementioned frequency-related parameter mapping and hierarchical adjustment mechanism, this invention overcomes the existing technology's view that a single electrical unit cannot handle multi-frequency regulation under conditions of multiple harmonics coexisting, and that stable suppression can only be achieved by increasing the number of hardware devices or adopting complex filtering structures. During continuous system operation, the control processing unit repeatedly executes data acquisition, admittance modeling, abnormal branch identification, and parameter adjustment processes according to a preset cycle. When the load combination of the distribution cabinet changes or the harmonic distribution state changes, the system can automatically update the abnormal branch set and parameter configuration instructions, enabling the admittance structure inside the distribution cabinet to dynamically evolve with the operating state, rather than maintaining a static compensation state.

[0047] During the long-term operation of the distribution cabinet, the system described in this embodiment does not rely on one-time parameter configuration or manual tuning. Instead, it forms a continuous closed-loop operation mechanism by periodically executing a complete data acquisition, admittance modeling, abnormal branch identification, and parameter adjustment process. This closed loop is not a traditional fast control closed loop, but a structural closed loop that adjusts the internal electrical structure of the distribution cabinet. Its operating cycle can be set according to the on-site operating conditions, for example, executing a complete process once every second or minute.

[0048] Under normal operating conditions, when the load combination inside the distribution cabinet remains relatively stable, the admittance distribution of each branch at each harmonic frequency point changes little. The control processing unit only updates the admittance distribution during periodic detection without triggering significant parameter adjustments. At this time, the configurable electrical units maintain their current parameter states, and the system operates in a low-intervention mode, without additional impact on the original electrical behavior of the distribution cabinet. When the load combination changes, such as the addition or removal of a high-power nonlinear load, the harmonic distribution state inside the distribution cabinet changes accordingly. The control processing unit reconstructs the admittance distribution data at each harmonic frequency point within the new sampling period and identifies new abnormal branches or updates the admittance deviation of existing abnormal branches during horizontal comparison. In this case, the system does not assume the abnormal branches are persistent but treats them as dynamic results under operating conditions, thus avoiding long-term over-adjustment of fixed branches.

[0049] During the adjustment and execution phase, parameter configuration commands are sent to the corresponding configurable electrical units via the control interface. Since the parameter configuration commands have already undergone frequency-related decomposition and hierarchical sorting in logic, each configurable electrical unit only receives parameter component adjustment information relevant to itself during execution, without needing complex decision-making capabilities, thus reducing the requirements for the intelligence level of the unit hardware. This design allows the method described in this embodiment to be deployed on the basis of existing distribution cabinet structures by adding limited control and adjustment modules, without requiring large-scale modifications to the original main circuit.

[0050] During long-term operation, when the system detects that a certain abnormal branch no longer exhibits admittance deviation characteristics over multiple consecutive cycles, the control processing unit will gradually reduce the adjustment amplitude of the corresponding electrical unit of that branch until it returns to its basic parameter state. This process is not a simple reset, but is completed through multi-cycle gradual adjustment, thereby avoiding the impact of parameter abrupt changes on the operational stability of the distribution cabinet.

[0051] For a long time, the relevant technical field has held that the harmonic behavior inside distribution cabinets is highly random and strongly coupled, and its distribution is mainly determined by load characteristics, making it difficult to achieve stable control through adjusting the structural parameters of the distribution cabinet itself. Influenced by this bias, existing solutions mostly focus on adding filtering devices outside the distribution cabinet or suppressing single harmonic sources, while ignoring the decisive role of the branch admittance structure inside the distribution cabinet on the harmonic propagation path. This embodiment, by introducing admittance distribution state modeling, abnormal branch identification, and frequency-related parameter adjustment mechanisms, transforms the originally uncontrollable harmonic distribution problem into a quantifiable, comparable, and adjustable structural problem. By intervening at the branch level rather than the harmonic source level, the distribution relationship of harmonic currents is reconstructed inside the distribution cabinet, overcoming the aforementioned technical bias from an engineering implementation perspective.

[0052] Furthermore, this embodiment does not rely on complex external algorithms or computationally expensive models. Instead, it constructs adjustment logic based on the physical relationships between electrical parameters, ensuring the system's feasibility even in industrial environments with limited computing resources. This design makes the method described in this embodiment applicable not only to newly built power distribution systems but also feasible for retrofitting existing distribution cabinets.

[0053] To facilitate a deeper understanding of the technology in this invention, a detailed description of a harmonic suppression method for power distribution cabinets based on multi-source data fusion, as disclosed in the embodiments of this application, is provided below. Please refer to Figure 1 for a schematic diagram of the invention steps. The method includes the following steps: Step 1: Synchronously acquiring the operating signals of multiple parallel branches within the power distribution cabinet; extracting multi-frequency harmonic components from the acquired voltage and current signals of each branch; and obtaining the corresponding branch voltage amplitude and branch current amplitude at each preset harmonic frequency point. Specifically, multiple parallel-operating branches are typically set up inside the power distribution cabinet. Each branch may connect to different types of load units, and their operating states have a certain correlation in the time dimension. To avoid distortion of the phase relationship between branches due to sampling time offset, this embodiment uses a synchronous acquisition method to acquire the operating signals of multiple parallel branches. The synchronous acquisition mentioned here does not simply mean that the sampling actions are triggered at the same time, but rather that the voltage and current signals of each branch are time-aligned and sampled under a unified time reference, so that the signal data corresponding to different branches at the same sampling time can reflect the true operating state of the power distribution cabinet at that instant.

[0054] After synchronous acquisition is completed, multi-frequency harmonic component extraction is performed on the voltage and current signals obtained from each branch. It should be noted that this multi-frequency harmonic component extraction is not limited to a specific mathematical transformation form. Its purpose is to decompose the original time-domain signal into several frequency components corresponding to preset harmonic frequency points, so as to characterize the harmonic characteristics of each branch at the frequency domain level.

[0055] As one possible implementation, the acquired voltage and current signals can be analyzed using discrete Fourier transform, short-time Fourier transform, or equivalent frequency domain analysis methods to extract the frequency components corresponding to each preset harmonic frequency point. The preset harmonic frequency points can be set based on the fundamental frequency of the power distribution system, for example, by determining them based on integer multiples of the fundamental frequency. However, this application does not limit this to a single setting, and the specific settings can be adjusted according to the actual operating environment of the power distribution cabinet and the target harmonic suppression type.

[0056] At each preset harmonic frequency point, calculate the voltage amplitude and current amplitude of the corresponding branch. Here, the voltage amplitude and current amplitude refer to the effective amplitude or equivalent amplitude of the extracted frequency component at that harmonic frequency point, and their calculation method should be consistent between the voltage signal and current signal of the same branch.

[0057] It should be noted that the voltage signal and the current signal do not play equivalent roles in step one in this application. The voltage signal is mainly used to characterize the potential conditions borne by the branch at the corresponding harmonic frequency point, while the current signal reflects the harmonic current response characteristics of the branch at that frequency point. In addition, the meaning of multi-source data in this application includes not only spatial multi-source data from different branches, but also frequency multi-source data formed by the same branch at different harmonic frequency points, as well as type multi-source data composed of the two physical quantities of voltage and current.

[0058] Step 2: At each harmonic frequency point, calculate the equivalent admittance parameters of each branch based on the voltage and current amplitudes of the corresponding branches, and normalize the equivalent admittance parameters of different branches at the same harmonic frequency point to form the admittance distribution data of the distribution cabinet at that harmonic frequency point. The core of this step is to perform admittance calculation, structured sorting and differential processing on each branch at each preset harmonic frequency point, thereby forming a structural characterization quantity that can directly reflect the relative admittance characteristics of the branch.

[0059] Specifically, firstly, at the target harmonic frequency point, for each branch, the voltage amplitude is collected... With current amplitude Calculate the equivalent admittance magnitude parameter ,in, Indicates the branch number, Indicates the target harmonic frequency point. This indicates that the amplitude is taken as an absolute value. It should be noted that in this application, the admittance amplitude parameter only considers the amplitude and does not directly use the phase angle information. This is because in a multi-branch parallel system, the amplitude difference plays a major role in the identification of abnormal branches, while the phase difference can be introduced in subsequent higher-order analyses to ensure the stability and comparability of the basic data.

[0060] Subsequently, the admittance amplitude parameters of each branch were... Arranged according to a preset sorting rule to form an admittance sequence. This describes the relative magnitude of branch admittances at the same frequency. The sorting rule can be from largest to smallest or from smallest to largest, and weights can be adjusted according to engineering needs, such as weighting specific load branches to highlight their relative contribution to harmonic propagation.

[0061] Then, the admittance amplitudes of adjacent branches are calculated differentially to obtain the structural characterization quantity. This is used to reflect the gradient of admittance changes between adjacent branches at a given harmonic frequency, and can quantify the degree of unevenness or anomalous contribution of branch admittance distribution. In implementation, this can be achieved by constructing a two-dimensional matrix. The system stores all branch differential parameters, where rows represent branch numbers, columns represent adjacent admittance differences, and matrix elements are structural characterization quantities. This matrix-based data structure can be directly input into subsequent calculation modules for branch anomaly detection and electrical unit adjustment calculations.

[0062] It should be noted that the "admittance distribution state data" in this application not only includes the aforementioned structural characterization quantities, but also includes the identification information of each branch and the corresponding harmonic frequency point information, forming a ternary dataset. This dataset reflects both the relative admittance distribution of branches at a single frequency and allows for horizontal comparison of admittance characteristics at different harmonic frequencies.

[0063] The admittance amplitude parameter is further normalized to eliminate the influence of differences in absolute voltage amplitudes across different branches on the structural characterization parameters. Linear normalization can be used as the normalization method. or standardization ,in and These represent the mean and standard deviation of the admittance amplitudes of all branches at that frequency point, respectively. After normalization, the calculation of structural characterization parameters is also applicable to the normalized admittance sequence, allowing for comparisons of admittance distributions across branches and systems at different frequency points or between different cabinets.

[0064] Step 3: Based on the admittance distribution data, compare and determine the equivalent admittance parameters of each branch at each harmonic frequency point, and identify abnormal branches whose equivalent admittance deviates from the preset admittance distribution range; please refer to the schematic diagram shown in Figure 2. Specifically, for each target harmonic frequency point... The admittance amplitude sequence of each branch in step two. and corresponding branch road signs Construct as an admittance structure state vector ,in, This represents the total number of parallel branches in the distribution cabinet. branch road The admittance structure characterization quantity at this frequency point not only reflects the branch admittance amplitude, but also includes the gradient information of the branch in the overall admittance structure and the relative relationship of the admittances of adjacent branches.

[0065] For the branch to be determined While keeping the admittance characteristics of other branches unchanged, a preset structural disturbance is introduced. Generate the perturbation admittance structure state vector The disturbance quantity Generally, it is a characterization of the original structure of the branch. The preset ratio range of ±5% to 15% is set by engineering based on actual load fluctuations and branch characteristics, and can simulate the possible dynamic changes of the branch under the action of harmonics. In implementation, the disturbance can also be mapped using nonlinear functions, such as those generated based on the sine, exponential, or piecewise functions of the load current or voltage harmonic amplitude, thereby reflecting the real scenario of nonlinear changes in branch admittance with operating conditions.

[0066] After the disturbance is generated, the weighted norm is used to calculate the degree of influence of the branch disturbance on the overall admittance structure, and the structural influence parameter is obtained. Among them, the weighted norm Defined as: ,in, For the first The weights of each branch in the admittance structure are determined based on its current capacity, admittance magnitude, physical location, and topological connections within the distribution cabinet. By introducing these weights, the contribution of branch disturbances to the overall admittance distribution can be accurately reflected, rather than simply numerical differences, ensuring that anomaly detection aligns with actual engineering conditions. In implementation, the weight matrix can be pre-stored in the controller and dynamically adjusted based on the operating status.

[0067] The calculated structural influence parameters were then compared with the preset admittance structural stability range. When comparing, If the interval is exceeded, branch i is determined to be an abnormal branch. This range can be set based on historical operating data statistics, admittance variation characteristics, and engineering experience to ensure that branches with normal fluctuations are not misjudged. In implementation, different stability ranges can be set for different frequency points to reflect the differences in the sensitivity of branches to higher harmonics.

[0068] In engineering implementation, the admittance structure state vector, perturbation vector, weight matrix, and judgment threshold can be stored in the memory data table of an embedded controller or industrial PC. The processing flow includes: 1) periodically collecting admittance data in step two; 2) constructing the admittance state vector matrix; 3) applying perturbations to each branch in sequence; 4) calculating the structural influence degree in parallel; and 5) updating the list of abnormal branches.

[0069] To ensure data consistency, branch identifiers and frequency points must be strictly aligned in the data table. The controller can generate the next electrical unit adjustment command based on the list of abnormal branches, thus achieving closed-loop harmonic control.

[0070] In modern power systems, nonlinear loads, frequency converters, power interface inverters, and other equipment generate multi-frequency harmonics. Relying solely on the identification of abnormal branches at a single frequency point is prone to misjudgment and omission. Therefore, this invention provides a technical means for identifying multi-frequency abnormal branches by performing cross-frequency identification when multiple harmonic frequency points exist simultaneously. In specific implementation, the admittance distribution state data generated in step two is first integrated across frequencies to form the admittance structure feature matrix for each branch. It should be noted that the admittance structure feature matrix in this application differs from the single-frequency admittance amplitude parameter; it reflects the admittance changes of the same branch at multiple harmonic frequency points and its contribution to the overall admittance distribution structure. Specific operations include: for the same branch i, at each preset harmonic frequency point... Next, extract the structural influence parameters obtained from the aforementioned calculations. And arranged in order of frequency dimension to form a vector. ,in, The total number of harmonic frequency points considered. Indicates at frequency point The influence of structural disturbances in the lower branch on the overall admittance distribution is numerically calculated based on the weighted norm. This is accomplished by combining the relative contribution weights of each branch in the admittance structure.

[0071] Subsequently, in the cross-frequency feature vector Based on this, cross-frequency anomaly detection is performed. Specifically, this includes: 1. Frequency threshold determination, considering the structural influence parameter at each frequency point. With the corresponding admittance structure stability region If a comparison is made, If the frequency point is an abnormal contribution point, then that frequency point is marked as such. It should be noted that the stable range of the admittance structure in this application is determined based on historical operating data and simulation analysis, which can reflect the safe range of branch admittance under normal fluctuations, while avoiding misjudgment caused by single-frequency anomaly judgment.

[0072] II. Cross-frequency consistency determination: Analyze the frequency point marking results sequentially and calculate the cross-frequency variation amplitude. and consistent with the preset range In comparison, if And if all frequency points exceed the admittance stability range, then the branch will be... It was determined to be a multi-frequency abnormal branch. It should be noted that the consistency range in this application... The settings take into account the natural amplitude differences between harmonic frequencies and the adjustable range of branch admittance, which can effectively eliminate the interference of occasional single-frequency anomalies and improve the accuracy of cross-frequency determination.

[0073] In terms of software implementation, this application will use cross-frequency feature vectors. As input, the determination is completed through modular processing: First, the admittance data integration module generates a cross-frequency matrix, with each row corresponding to a branch and each column corresponding to a harmonic frequency point; then, the cross-frequency consistency analysis module calculates the frequency threshold exceeding the marker and amplitude change for each branch. Finally, the multi-frequency anomaly determination module outputs a set of multi-frequency anomaly branches, which is used for the selection of configurable electrical units and the calculation of adjustment quantities in subsequent step four. It should be noted that the entire data stream can be operated in real-time or periodic acquisition mode, and supports dynamic updates during the operation of the distribution cabinet.

[0074] As one possible implementation, the cross-frequency determination process in this application can employ linear weighting or exponential weighting to normalize the structural influence parameters at different frequency points, thereby further enhancing the ability to identify the contribution of high-frequency or low-frequency frequencies to the overall admittance structure. For example, the weighted cross-frequency consistency calculation formula can be defined as follows: ,in, The frequency weighting coefficient can be set according to the frequency's sensitivity to harmonic propagation and the importance of the branch, ensuring that multi-frequency anomaly detection takes into account the actual influence of different frequency points. It should be noted that the frequency weighting setting differs from the traditional equal processing method, and can emphasize key harmonic frequency points, improving the accuracy and reliability of anomaly branch identification.

[0075] This invention, through cross-frequency structural influence analysis, offers significant advantages over traditional single-frequency anomaly detection: First, it can identify branches that continuously dominate admittance disturbances at multiple frequency points, avoiding misidentification or omissions caused by single-frequency detection; second, it provides quantitative and calculable criteria for multi-frequency anomaly detection, making the subsequent adjustment of configurable electrical units in step four more precise; third, through consistency analysis in the frequency dimension, it can stably identify multi-frequency anomaly branches under different load conditions, improving the robustness and reliability of the system. As one possible implementation, this invention can form a 12×9 matrix for 12 branches and 9 harmonic frequency points, simultaneously performing amplitude and consistency determination on the cross-frequency vector of each branch to achieve multi-frequency anomaly branch output, providing a precise basis for subsequent configurable electrical unit adjustment.

[0076] Step 4: Identify the configurable electrical units involved in harmonic current conduction in each abnormal branch, and determine the electrical parameter adjustment amount corresponding to the configurable electrical units based on the deviation of the equivalent admittance parameter of each abnormal branch at the corresponding harmonic frequency point. This step is used to further determine which electrical units inside the abnormal branch have effective adjustable capability at the target harmonic frequency point, provided that the abnormal branch has been identified, and to convert the equivalent admittance deviation at the branch level into parameter adjustment amounts that can be directly sent to the equipment side.

[0077] Please refer to Figure 3 for the flowchart of configurable electrical unit identification and admittance contribution allocation for abnormal branches. In specific implementation, the system first targets a certain identified abnormal branch at the target harmonic frequency point. The internal structure information of the branch is then read. This structure information refers not only to the topological connections, but also includes the physical installation location of each electrical unit within the cabinet, its connection method to the busbar or filter branch, and whether it is located on the main conduction path of harmonic currents. As one possible implementation, this information can be determined by the distribution cabinet design drawings and field configuration files, and registered during the system initialization phase.

[0078] Subsequently, the system obtains the engineering parameter configuration table of each electrical unit within the abnormal branch. This parameter configuration table includes at least: 1) nominal reactance or equivalent impedance value; 2) damping parameters under rated operating conditions; 3) whether online adjustment is supported and the corresponding adjustment method (continuous adjustment or discrete range); 4) the upper and lower limits of safe adjustment for each adjustable parameter. It should be noted that "adjustable parameters" are different from "theoretical variable parameters," referring only to parameters that can be adjusted through the control interface under the condition that the distribution cabinet is operating normally and the load is not disconnected.

[0079] After completing parameter acquisition, the system locates the target harmonic frequency point. An engineering equivalent admittance model for the abnormal branch is constructed below. Unlike purely theoretical modeling, this model incorporates the following engineering assumptions during its construction: 1. High-order parasitic parameters that contribute less to admittance variation than the measurement resolution are ignored; 2. Only parameters that have a major impact on the admittance amplitude at the target harmonic frequency are retained.

[0080] The above constraints make the model closer to the actual adjustment effect, rather than pursuing complete mathematical precision.

[0081] Based on this model, the system applies parameter perturbations to the adjustable parameters of each electrical unit within the abnormal branch. The perturbation amplitude is typically set to 1%–5% of the parameter's allowable adjustment range, preferably 2%–3%. This range ensures that the admittance change is greater than the measurement noise while preventing excessive perturbation from causing model nonlinear failure or triggering protection actions.

[0082] Under the condition of applying a perturbation to a single electrical unit while keeping the parameters of other units unchanged, the system recalculates the equivalent admittance of the abnormal branch at the target harmonic frequency and obtains the corresponding admittance change. To avoid misjudgment, the system does not directly use this change for adjustability judgment, but introduces dual engineering thresholds for screening.

[0083] The admittance measurement uncertainty threshold is determined by the resolution of the acquisition device at the harmonic frequency point, for example, by estimating it based on the voltage and current sampling accuracy and signal processing algorithms. The admittance modeling error threshold is obtained by calibration using historical operating data and is used to reflect systematic deviations caused by model simplification. When the admittance change caused by parameter disturbance of a certain electrical unit exceeds both of the above thresholds simultaneously, the system considers the change to be a measurable, distinguishable, and controllable engineering response, thereby identifying the electrical unit as a configurable electrical unit with actual adjustment capability for the equivalent admittance of abnormal branches at the target harmonic frequency point.

[0084] It should be noted that this judgment mechanism can effectively exclude two types of units: one type is units whose parameters are adjustable but contribute very little to the admittance at the target harmonic frequency point; the other type is units that theoretically affect the admittance, but whose changes are drowned out by measurement noise or model error.

[0085] After forming a set of configurable electrical units, the system further calculates the relative contribution ratio of each unit to the admittance deviation of abnormal branches based on the magnitude of the admittance change caused by each unit under the same disturbance conditions. This ratio is used to reasonably decompose the admittance deviation of abnormal branches and avoid a single electrical unit bearing an excessive adjustment task.

[0086] Finally, based on the engineering parameter-admittance mapping relationship of each configurable electrical unit, the system converts the allocated target admittance correction amount into a specific parameter adjustment amount, and performs boundary verification on the obtained adjustment amount to ensure that it does not exceed the safe operating range of the equipment, which serves as the direct input for the generation of subsequent control commands.

[0087] In actual power distribution cabinet operation environments, when multiple harmonic frequency points coexist, a single electrical unit may face conflicting adjustment targets at different harmonic frequency points. This problem is not a random occurrence in theoretical derivation, but an inevitable engineering phenomenon that arises after the widespread integration of nonlinear loads into the power distribution system. Therefore, this invention addresses this issue by performing cross-frequency constraint processing in advance during the parameter adjustment calculation stage.

[0088] It should be noted first that the “cross-frequency constraint processing” in this application is different from adjusting each harmonic frequency point independently. Its core purpose is not to achieve the optimal admittance correction effect at each harmonic frequency point, but to ensure that the adjustment commands at each harmonic frequency point have engineering consistency that can be executed simultaneously at the same electrical unit level, while ensuring that the overall equivalent admittance deviation of the abnormal branch does not deteriorate.

[0089] In practical implementation, after completing the first part of step four and identifying the set of configurable electrical units for the abnormal branch, the system does not immediately use the target admittance correction calculated at each harmonic frequency point for parameter adjustment calculation. Instead, it enters the cross-frequency consistency analysis stage. Specifically, please refer to the logic diagram for generating multi-frequency constraints and admittance adjustment paths shown in Figure 4. First, for the same abnormal branch, the system reads the target admittance correction of each configurable electrical unit at the corresponding frequency point under multiple harmonic frequencies of interest. The target admittance corrections are all derived from the results obtained based on the admittance allocation coefficient in the first part of step four, and maintain a unified positive and negative sign convention, where a positive value indicates that the equivalent admittance at that frequency point needs to be increased, and a negative value indicates that it needs to be decreased.

[0090] Subsequently, the system reorganizes the aforementioned admittance corrections based on the electrical unit, rather than on harmonic frequency points. Specifically, for any configurable electrical unit, the target admittance corrections corresponding to multiple harmonic frequency points are arranged in ascending order of frequency, forming a multi-frequency admittance correction sequence for that electrical unit. This sequence reflects the comprehensive regulation pressure borne by the same hardware unit under different frequency regulation requirements.

[0091] After obtaining the multi-frequency admittance correction sequence, the system undergoes cross-frequency consistency analysis. This analysis focuses on two key engineering dimensions: symbol direction consistency and amplitude deviation.

[0092] In the sign direction consistency analysis, the system determines whether the target admittance correction of the same electrical unit at different harmonic frequencies has inconsistent positive and negative directions. For example, it may require increasing admittance at lower harmonic frequencies while requiring decreasing admittance at higher harmonic frequencies. It should be noted that in this application, such situations are considered potential cross-frequency regulation conflicts because in actual hardware, the adjustment of the same parameter often affects multiple frequency points simultaneously, and the adjustment direction is difficult to completely decouple.

[0093] In amplitude deviation analysis, the system further compares the relative magnitudes of the target admittance correction for the same electrical unit at different harmonic frequencies. To this end, a cross-frequency deviation threshold is introduced, which limits the maximum permissible proportional difference between adjustment requirements at different frequency points. As one possible implementation, this threshold can be set to 30%–50% of the maximum achievable admittance adjustment of the electrical unit; the specific value can be pre-configured based on the type of electrical unit and its frequency response characteristics.

[0094] When there is a discrepancy in the sign direction or an amplitude difference exceeding the cross-frequency deviation threshold in the multi-frequency admittance correction sequence of a configurable electrical unit, the system marks the electrical unit as having a cross-frequency admittance correction conflict. It is important to emphasize that this marking does not mean the electrical unit is unusable, but rather that its current multi-frequency regulation objectives cannot be directly and simultaneously met in engineering practice.

[0095] For the marked electrical units, the system enters the cross-frequency constraint renormalization stage. In this stage, the system does not simply abandon the adjustment requirements of some harmonic frequency points, but redistributes the multi-frequency admittance correction sequence under the premise that the overall equivalent admittance deviation of the constrained abnormal branch does not increase.

[0096] In practice, the system first evaluates the contribution of each harmonic frequency point to the admittance deviation of the anomalous branch. This contribution can be directly derived from the structural influence parameter obtained in step three or its normalized result. The higher the contribution of a harmonic frequency point, the more significant its corresponding admittance anomaly's impact on the overall harmonic distribution of the branch. Based on this, the system increases the constraint priority of the admittance correction amount corresponding to high-contribution harmonic frequency points, i.e., it tries to keep its original adjustment target from being weakened. At the same time, for harmonic frequency points with lower contribution, the corresponding admittance correction amount is subjected to amplitude compression or sign softening, so that its adjustment demand is closer to the high-priority frequency points.

[0097] It should be noted that the "constraint priority" in this application is not a simple on / off relationship, but rather reflects the allocation ratio of the admittance correction adjustment range. Its essence is a cross-frequency compromise allocation mechanism under the premise that the overall admittance target of the branch does not deteriorate.

[0098] After completing the cross-frequency constraint renormalization, the system re-outputs the effective admittance correction for each configurable electrical unit at each harmonic frequency. This effective admittance correction satisfies the following requirements: 1. For the same electrical unit, the adjustment direction at each frequency point has executable consistency; 2. It does not introduce new abnormal branch admittance deviations overall; 3. It provides stable and feasible input conditions for subsequent parameter-admittance mapping calculations. The aforementioned effective admittance correction is then used as constraint input in the final calculation of electrical parameter adjustment, thereby ensuring the continuity and engineering controllability of the entire harmonic suppression process under multi-frequency coexistence conditions.

[0099] To address the risks of sudden admittance changes, branch transient instability, or regulation oscillations that may occur during actual electrical parameter adjustment, the adjustment path itself is constrained and limited. The core focus is not on whether the final admittance reaches the target, but on whether the entire process from the current state to the target state is continuous, controllable, and does not introduce new harmonic risks. It is important to note that in this application, "electrical parameter adjustment path" differs from "electrical parameter target value." The former describes the sequence of changes in electrical parameters during the adjustment process, while the latter only indicates the adjustment endpoint. By limiting the adjustment path, this application avoids situations where admittance requirements are met only at the endpoint, but adverse effects are caused to the power distribution system during intermediate adjustments.

[0100] In practical implementation, after obtaining the effective admittance correction of each configurable electrical unit at each harmonic frequency point, the system performs path modeling of the adjustment process by combining the current electrical parameter state and the target electrical parameter state.

[0101] First, for each configurable electrical unit, the system simulates the equivalent admittance change process as the electrical parameters gradually change from the current state to the target state, based on the parameter-admittance mapping relationship of that unit. This simulation is not a continuous-time model, but rather discretized in units of parameter change steps. In other words, the system breaks down the entire parameter adjustment process into several parameter change nodes, each node corresponding to a specific electrical parameter value and its equivalent admittance state at each harmonic frequency.

[0102] In this process, the system represents the admittance change process of each configurable electrical unit at each harmonic frequency point as a set of discrete admittance sequences that increase with the parameter change step size. This discrete admittance sequence clearly characterizes the intermediate transition states between the initial admittance state and the target admittance state, providing basic data for subsequent path risk assessment. The discrete admittance sequence is then analyzed segment by segment. Specifically, for two adjacent parameter change nodes, the system calculates the change amplitude between adjacent admittance states at the same harmonic frequency point. This change amplitude reflects the instantaneous impact on the harmonic characteristics of the distribution cabinet during a single parameter adjustment operation.

[0103] To impose engineering constraints on this variation range, the system sets upper limits for admittance variation at different harmonic frequency points. It should be noted that the upper limits for admittance variation described in this application are not uniform constants, but rather parameters related to the harmonic frequency point, branch rated capacity, and electrical unit type. As one possible implementation, a relatively small upper limit for admittance variation can be set at lower harmonic frequencies to prevent disturbances to the system's fundamental frequency and major harmonic channels; while a relatively larger variation range can be allowed at higher harmonic frequencies.

[0104] When the system detects that the amplitude of the change between adjacent admittance states in a discrete admittance sequence exceeds the corresponding upper limit threshold of admittance change at any harmonic frequency point, it determines that the electrical parameter adjustment path has a risk of admittance abrupt change. It should be noted that the risk of admittance abrupt change is not the same as the occurrence of system instability, but rather refers to the possibility that the adjustment path may induce transient harmonic amplification or a sudden increase in branch current in engineering terms.

[0105] For electrical parameter adjustment paths deemed to pose a risk of admittance abrupt change, the system does not directly reject the adjustment target, but instead enters the parameter change step size reconstruction stage. In this stage, the system segments the original parameter change step size, breaking down the originally large single parameter adjustment operation into multiple smaller, continuous adjustment steps.

[0106] In practice, the system reverse-calculates the maximum allowable parameter change step size based on the admittance change upper limit threshold, and regenerates the parameter change step size sequence accordingly. This sequence, while keeping the initial and target parameter states unchanged, increases the number of parameter change segments and reduces the amplitude of each segment, ensuring that the change amplitude between any adjacent admittance states is limited to the admittance change upper limit threshold at the corresponding harmonic frequency point.

[0107] It should be noted that the "segmented reconstruction processing" in this application is not a simple equal-step subdivision, but rather a non-uniform segmentation based on the constraint strength of different harmonic frequency points. For example, in the harmonic frequency range that is more sensitive to the impact on the system, the parameter change step size can be further reduced, while in the frequency range with relatively loose constraints, a relatively larger step size is allowed.

[0108] After completing the segmented reconstruction process, the system generates a constrained parameter adjustment trajectory based on the reconstructed parameter change step sequence. This trajectory clearly defines the change sequence, change magnitude, and corresponding admittance evolution path of the electrical parameters throughout the entire adjustment process, and serves as the path constraint input for subsequent electrical parameter adjustments.

[0109] Step 5: During the operation of the distribution cabinet, steps 1 to 3 are periodically repeated to update abnormal branches and generate parameter configuration instructions for configurable electrical units based on the corresponding electrical parameter adjustment. It should be noted that periodic repetition does not mean that abnormal branch updates or parameter adjustments will necessarily be triggered in every operating cycle. Rather, it means that the system continuously monitors the admittance distribution state changes of the distribution cabinet at a preset time scale during operation and decides whether to enter the subsequent adjustment process based on the changes.

[0110] In practical implementation, after the power distribution cabinet is put into operation, the system starts the operational monitoring module. This module calls steps one through three at a fixed or adaptive time period. The time period can be set according to the type of load connected to the power distribution cabinet, the frequency of load changes, and the system capacity. For example, it can be set to several seconds to tens of seconds in industrial scenarios, and can be further shortened in scenarios with high requirements for dynamic response.

[0111] In each periodic call, the system first synchronously acquires the operating signals of each parallel branch according to step one and extracts multi-frequency harmonic components; then, it constructs the admittance distribution state data for the current operating cycle according to step two; and finally, it identifies abnormal branches according to step three. Thus, the system obtains "the set of abnormal branches and their corresponding admittance structure characteristics for the current operating cycle," rather than immediately executing adjustments.

[0112] To avoid frequent adjustments due to minor measurement fluctuations or short-term disturbances, this embodiment introduces an admittance state change trigger condition in step five to determine whether a parameter configuration instruction should be generated. The trigger condition describes whether the current operating state has undergone an engineering-significant change relative to the previous operating cycle.

[0113] As a basic triggering condition, the system first compares the set of abnormal branches identified in the current operating cycle with the set of abnormal branches in the previous operating cycle. When the two change at the branch identification level, such as the addition of an abnormal branch, the restoration of an existing abnormal branch to a normal state, or a change in the number of abnormal branches, the system determines that the harmonic distribution structure of the distribution cabinet has undergone a topological change, and the triggering condition is met.

[0114] As another type of triggering condition, the system further compares the changes in the equivalent admittance parameters of existing abnormal branches at the target harmonic frequency point. Specifically, for the same abnormal branch and the same harmonic frequency point, the system calculates the magnitude of the change between the equivalent admittance parameter in the current operating cycle and the corresponding value in the previous operating cycle, and compares this magnitude with a preset admittance change threshold. It should be noted that the "admittance change threshold" is different from the measurement noise tolerance; its purpose is not to eliminate measurement errors, but to distinguish between "negligible operational fluctuations" and "state changes requiring readjustment." As one possible implementation, this threshold can be set according to the proportion of the branch's rated admittance, for example, limited to a certain percentage of the rated admittance, and different thresholds can be set for different harmonic frequency points.

[0115] When the change in the equivalent admittance parameter of any abnormal branch at the target harmonic frequency exceeds the admittance change threshold, the system determines that the harmonic conduction characteristics of the abnormal branch have undergone a substantial change, even if the set of abnormal branches itself has not changed, it is considered to meet the triggering condition.

[0116] It should be noted that in this application, "the abnormal branch set changes" and "the abnormal branch admittance parameter changes exceed the threshold" are parallel triggering conditions. The subsequent process can be triggered if either one is met, which is used to cover two types of operating scenarios: structural changes and state changes, respectively.

[0117] Only when one of the above triggering conditions is met will the system, based on the updated abnormal branch information, call the electrical parameter adjustment calculation results determined in step four to generate a parameter configuration instruction for the configurable electrical unit. The parameter configuration instruction explicitly includes the target electrical unit identifier, corresponding parameter items, adjustment direction, adjustment range, and adjustment path constraint information, used to guide subsequent execution layer operations.

[0118] When the triggering condition is not met, that is, the set of abnormal branches remains stable in the current running cycle and the equivalent admittance change of each abnormal branch is within the threshold range, the system will keep the parameter configuration status issued in the previous cycle unchanged, and will only continue to perform monitoring without generating new parameter configuration instructions.

[0119] Step 6: Adjust the frequency-related electrical parameters of the configurable electrical units in the abnormal branch according to the parameter configuration instructions, thereby changing the equivalent admittance parameter of the abnormal branch at the corresponding harmonic frequency point. Here, the frequency-related electrical parameters are not the natural frequency response of a single nominal parameter at different frequencies, but rather refer to parameter components that are artificially divided within the electrical unit and can be independently adjusted. These components establish a correspondence with a specific harmonic frequency point at the control interface and parameter organization level, and can have a major impact on the equivalent admittance at that frequency point.

[0120] In practice, after step five generates the parameter configuration instruction for the configurable electrical unit in the abnormal branch, the execution module first parses the equivalent admittance correction requirement information contained in the instruction. The equivalent admittance correction requirement is not a single value, but a set formed by indexing harmonic frequencies. For example, when multiple target harmonic frequency points exist simultaneously, a set of discrete admittance targets are formed for the same configurable electrical unit.

[0121] The set of admittance targets can be represented as: in, Indicates the first One target harmonic frequency point, This represents the effective admittance correction amount allocated to the configurable electrical unit at that frequency point. It should be noted that this admittance correction amount originates from the result of the cross-frequency constraint processing in step four, and already satisfies the constraint condition that the overall admittance deviation of the abnormal branch does not increase.

[0122] After obtaining the admittance target set, the system enters the frequency-related parameter mapping stage. The core of this stage lies in establishing the mapping relationship between the admittance target and the internal parameters of the electrical unit, rather than a simple proportional conversion.

[0123] Specifically, for each configurable electrical unit, the system pre-stores or builds a frequency-dependent parameter mapping model for that unit online. This model describes which parameter components within the electrical unit have a dominant influence on the equivalent admittance at different harmonic frequencies, and the independence boundaries between these parameter components.

[0124] As one possible implementation, an electrical unit containing variable reactance and variable damping structures can be internally abstracted into multiple parallel or series equivalent branches. Each equivalent branch corresponds to one or a set of harmonic frequency ranges during design, and frequency separation is achieved through bandpass, notch filtering, or frequency-selective control structures. At the control level, each equivalent branch corresponds to an independent parameter component, such as an equivalent reactance component. or equivalent damping component .

[0125] Based on this, the system will assign each item in the admittance target set Each parameter is mapped to its corresponding component, and the required parameter adjustment at that frequency point is calculated using a frequency-dependent parameter mapping model. This mapping process can be represented as follows: ,in, This represents the adjustment amount of the electrical parameter component corresponding to the i-th harmonic frequency point. This refers to the frequency-related parameter mapping model. It is important to emphasize that the statement "each parameter component is electrically independent and uncoupled during adjustment" is not an abstract description, but rather means that in the parameter mapping model, the parameter components corresponding to different frequency points have no overlapping terms in the model variable space. In other words, adjusting a parameter component at a certain frequency point does not introduce significant changes in the admittance at other frequency points. This independence can be achieved through structural design, parameter decoupling modeling, or control interface isolation.

[0126] During the parameter configuration instruction execution phase, the execution module issues adjustment instructions to each frequency-related parameter component within the configurable electrical unit according to the frequency-related parameter mapping model. Specifically, the control system compares the target value of each parameter component with its current value and gradually adjusts it to the target state according to the constrained parameter adjustment trajectory defined in step four.

[0127] In this way, the same configurable electrical unit exhibits different equivalent admittance characteristics at different harmonic frequencies, without mutual interference in the frequency dimension due to uniform parameter adjustment. Thus, fine-grained suppression of multi-frequency harmonics can be achieved without increasing the number of hardware components.

[0128] To avoid introducing new admittance instabilities when adjusting the parameters of configurable electrical units in abnormal branches under multi-harmonic conditions, step 6 does not simultaneously adjust all frequency-related electrical parameter components when executing parameter configuration instructions. Instead, it introduces frequency-layered adjustment timing constraints to expand the parameter configuration instructions, ensuring a clear sequence and stability determination mechanism for the parameter adjustment process across the frequency dimension. It should be noted that the core of frequency-layered adjustment lies in treating parameter adjustments corresponding to different harmonic frequencies as adjustment behaviors at different system influence levels, and using timing constraints to prevent high-frequency adjustments from intervening prematurely before the low-frequency admittance structure has stabilized.

[0129] In practical implementation, the control system first sorts the target harmonic frequency points based on the equivalent admittance deviation data formed in steps four and five. The sorting is based not only on the harmonic frequency values ​​themselves but also on the relative magnitude of the admittance deviation of the abnormal branches corresponding to each frequency point. In this embodiment, the adjustment priority index for each harmonic frequency point can be defined as follows: ,in, The harmonic frequency point This represents the equivalent admittance deviation of the abnormal branch at this frequency point. and This is a weighting coefficient used to balance frequency-level factors and admittance deviation strength factors. This priority index allows for the formation of parameter adjustment sequences divided by frequency level. It should be noted that the statement "the lower the harmonic frequency, the higher the adjustment priority" is not an absolute rule. Rather, it means that, all other things being equal, the parameter components corresponding to low-frequency harmonics are given priority in the adjustment process to ensure the basic stability of the overall admittance structure of the distribution cabinet.

[0130] When executing the parameter adjustment sequence, the system sets an adjustment strategy individually for the parameter components at each frequency level. Specifically, for a certain target harmonic frequency level... The system sets an independent upper limit for the parameter change step size for its corresponding frequency-related parameter components. And the corresponding intermediate stability determination interval.

[0131] The upper limit of the parameter change step size is used to limit the transient impact of a single adjustment on the equivalent admittance, and its value can be determined based on the admittance sensitivity at that frequency point. The intermediate stability judgment interval is used to describe the allowable fluctuation range of the equivalent admittance of the abnormal branch at that frequency point after the parameter adjustment at that frequency level is completed. For example, the stability interval can be defined as: in, This refers to the admittance deviation after adjustment. This is a preset stability tolerance threshold at this frequency point. After completing the parameter component adjustment for the current frequency level, the system does not immediately enter the next frequency level. Instead, it re-acquires the equivalent admittance state of the abnormal branch at this harmonic frequency point through the online admittance state update module and compares it with the stability interval.

[0132] If the detection result satisfies the stability interval constraint, it indicates that the admittance structure at this frequency level has entered an acceptable stable state, and only then is the system allowed to perform parameter component adjustment at the next frequency level. Conversely, if the detection result does not satisfy the stability interval constraint, it is determined that the parameter adjustment at the current frequency level has caused an unexpected disturbance to the system admittance structure.

[0133] In response to this situation, the system will not simply terminate the adjustment process, but will trigger a backoff correction mechanism. Backoff correction refers to adjusting the parameter components of the current frequency level in the opposite direction or with reduced amplitude, while keeping the parameters of other frequency levels unchanged, so that the admittance state returns to the stable range. After the backoff correction is completed, the system re-enters the adjustment process at that frequency level until the stable range constraint is met.

[0134] In practice, adjustments to abnormal branches include: if there is a parallel capacitor bank on the abnormal branch, the equivalent capacitive admittance at that frequency is reduced by decreasing the number of switching groups; if a reactor is configured on the branch, the inductive characteristics at that frequency are changed by switching the reactor level; if an active device is connected, its current response characteristics at a specific harmonic frequency are changed by adjusting its output impedance or equivalent control parameters, and so on. It should be noted that the adjustment method depends on the branch and the device itself, and this invention does not limit it. At the same time, the backoff correction in this application does not negate the original adjustment result, but by introducing an intermediate stability determination, the parameter adjustment path has a self-correcting capability, thereby avoiding cascade instability of the admittance structure under multi-frequency harmonic conditions.

[0135] Finally, it should be noted that the mathematical formulas, derivations, symbol definitions, and parameter calculation methods used in this specification are all for the purpose of further clarifying and verifying the technical content of this invention, so that those skilled in the art can more intuitively and accurately understand the working mechanism and technical effects of this invention. These formulas are only used as quantitative expressions or illustrative examples of technical features and do not constitute limiting conditions of the claims of this invention. Those skilled in the art should understand that, without changing the core idea of ​​this invention, the parameter forms, calculation methods, numerical ranges, and even symbol representations involved in the formulas can be equivalently replaced or simplified in engineering according to the actual application environment. The specifics can be determined according to the actual situation, and no limitation is imposed. It should also be emphasized that the formulas in this specification are not theoretical derivations in the style of academic research papers, but rather an engineering description of the embodiments of this invention. Their purpose is to enhance the understandability and implementability of this invention, rather than to increase redundancy and complexity. Those skilled in the art can choose whether to use such quantitative tools when reading this specification, or can achieve the same technical effects through other equivalent methods.

[0136] Furthermore, while specific embodiments of the present invention have been described above, those skilled in the art should understand that these specific embodiments are merely illustrative. Those skilled in the art can omit, substitute, and modify the details of the above methods and systems in various ways without departing from the principles and essence of the present invention. For example, combining the above method steps to perform substantially the same function and achieve substantially the same result according to substantially the same method falls within the scope of the present invention. Therefore, the scope of the present invention is defined only by the appended claims.

Claims

1. A method for harmonic suppression in power distribution cabinets based on multi-source data fusion; characterized in that: Includes the following steps: Step 1: Synchronously collect the operating signals of multiple parallel branches in the distribution cabinet, extract multi-frequency harmonic components from the collected voltage and current signals of each branch, and obtain the corresponding branch voltage amplitude and branch current amplitude at each preset harmonic frequency point. Step 2: At each harmonic frequency point, calculate the equivalent admittance parameters of each branch based on the voltage and current amplitudes of the corresponding branches. Normalize the equivalent admittance parameters of different branches at the same harmonic frequency point to form admittance distribution data for the distribution cabinet at that harmonic frequency point. Step 3: Based on the admittance distribution data, compare and determine the equivalent admittance parameters of each branch at each harmonic frequency point, identifying abnormal branches whose equivalent admittance deviates from the preset admittance distribution range. Step 4: Determine the configurable components involved in harmonic current conduction in each abnormal branch. The electrical unit is configured, and the electrical parameter adjustment amount corresponding to the configurable electrical unit is determined based on the deviation of the equivalent admittance parameter of each abnormal branch at the corresponding harmonic frequency point; Step 5: During the operation of the distribution cabinet, steps 1 to 3 are periodically repeated to update the abnormal branches and generate parameter configuration instructions for the configurable electrical units based on the corresponding electrical parameter adjustment amount; Step 6: The frequency-related electrical parameters of the configurable electrical units in the abnormal branches are adjusted according to the parameter configuration instructions to change the equivalent admittance parameter of the abnormal branch at the corresponding harmonic frequency point.

2. The method for harmonic suppression in a distribution cabinet based on multi-source data fusion according to claim 1, characterized in that: In step 2, the admittance distribution data of the distribution cabinet at the harmonic frequency point is obtained by constructing the relative structural relationship of the equivalent admittance of the branches. The construction process includes: at the target harmonic frequency point, calculating the equivalent admittance amplitude parameters of each branch based on the voltage harmonic components and current harmonic components of the corresponding branch; arranging the equivalent admittance amplitude parameters of each branch according to a preset sorting rule to form an admittance sequence reflecting the relative magnitude relationship of the branch admittances; calculating the difference parameters between the admittance amplitudes of adjacent branches according to the admittance sequence, and using the difference parameters as the structural characterization quantity of the branch admittance distribution at the target harmonic frequency point; associating the structural characterization quantity with the corresponding harmonic frequency point and branch identifier to form admittance distribution data describing the relative structural characteristics of the branch admittance of the distribution cabinet at the target harmonic frequency point.

3. The method for harmonic suppression of power distribution cabinets based on multi-source data fusion according to claim 1, characterized in that: In step 3, the identification of abnormal branches is based on the degree of influence of the branch's equivalent admittance on the stability of the admittance distribution structure at the same harmonic frequency point. The identification process includes: at the target harmonic frequency point, based on the admittance distribution state data formed in step 2, extracting the admittance structure characterization quantity corresponding to each branch to form an admittance structure state set at that harmonic frequency point; for any branch to be determined, without changing the admittance structure characterization quantity of other branches, introducing a pre-set amplitude structural disturbance quantity into the admittance structure characterization quantity of the branch to obtain the corresponding disturbed admittance structure state; based on the admittance structure state before and after the disturbance, calculating the structural influence parameter of the branch to be determined; the structural influence parameter... The calculation formula is: in, The target harmonic frequency point; , represents the admittance structure state vector composed of the admittance structure characterization quantities of each branch at the harmonic frequency point; Indicates only for the first The perturbation admittance structure state vector formed after introducing a preset structural perturbation amount into a branch is used to simulate the variable range of the branch admittance under harmonic action. The preset structural perturbation amount does not exceed a preset proportion range of the characteristic quantity of the branch admittance structure. The weighted norm is used to reflect the relative influence weights of different branches in the admittance structure. This parameter is used to represent the disturbance intensity of the target branch admittance change on the overall admittance distribution structure. When the structural influence parameter exceeds the preset admittance structure stability range, the branch to be judged is identified as an abnormal branch that has a dominant influence on the harmonic current distribution at the target harmonic frequency point.

4. The method for harmonic suppression in a distribution cabinet based on multi-source data fusion according to claim 1, characterized in that: In step 3, when multiple harmonic frequency points exist simultaneously, the identification of abnormal branches is based on the consistency of the admittance structure influence of the branch at different harmonic frequency points. The process includes: for the same branch, obtaining the corresponding structural influence parameters at multiple harmonic frequency points, and combining the structural influence parameters at each harmonic frequency point according to the frequency dimension to form a cross-frequency structural influence feature set for the branch; if the structural influence parameters corresponding to each harmonic frequency point in the cross-frequency structural influence feature set all exceed the admittance structure stability range of the corresponding frequency point, and the variation amplitude of the structural influence parameters in the frequency dimension is within a preset consistency range, then the branch is determined to be a multi-frequency abnormal branch that has a continuous dominant influence on the admittance distribution structure at multiple harmonic frequency points; if only some harmonic frequency points in the cross-frequency structural influence feature set have structural influence parameters that exceed the corresponding admittance structure stability range, or the variation amplitude of the structural influence parameters in the frequency dimension exceeds the consistency range, then the branch is not included in the multi-frequency abnormal branch set.

5. The method for harmonic suppression of power distribution cabinets based on multi-source data fusion according to claim 1, characterized in that: Step 4, the process of determining configurable electrical units and corresponding electrical parameter adjustment amounts for abnormal branches, includes: within the identified abnormal branches, obtaining the branch connection topology information and electrical parameter information of each electrical unit at the target harmonic frequency point. The electrical parameter information includes at least the nominal reactance value, damping parameter, control interface type, and adjustable parameter range of each electrical unit; based on the branch connection topology information and electrical parameter information, constructing an analytical expression for the equivalent admittance of the abnormal branch at the target harmonic frequency point, and expressing the equivalent admittance of the abnormal branch as a functional combination of the parameters of each electrical unit; in the analytical expression for equivalent admittance, applying a small parameter disturbance of a preset amplitude to each adjustable electrical parameter of each electrical unit within the abnormal branch, and calculating the change in equivalent admittance of the abnormal branch caused by the corresponding parameter disturbance; and comparing the change in equivalent admittance with the target harmonic frequency. The admittance measurement uncertainty threshold and the admittance modeling error threshold at the harmonic frequency point are compared. If the equivalent admittance change is greater than both the admittance measurement uncertainty threshold and the admittance modeling error threshold, the corresponding electrical unit is determined as a configurable electrical unit with adjustable equivalent admittance for the abnormal branch at the target harmonic frequency point, and a set of configurable electrical units for the abnormal branch is constructed. In the set of configurable electrical units, based on the ratio of the equivalent admittance change corresponding to each configurable electrical unit to the equivalent admittance deviation of the abnormal branch, the admittance allocation coefficient of each configurable electrical unit is calculated. Based on the admittance allocation coefficient and the equivalent admittance deviation of the abnormal branch at the target harmonic frequency point, the target admittance correction amount corresponding to each configurable electrical unit is determined. Based on the correspondence between the target admittance correction amount and the electrical parameters and admittance of each configurable electrical unit, the electrical parameter adjustment amount of each configurable electrical unit is calculated.

6. The method for harmonic suppression of power distribution cabinets based on multi-source data fusion according to claim 5, characterized in that: Step 4, when calculating the electrical parameter adjustment, performs cross-frequency constraint processing on the admittance correction requirements of the same abnormal branch at multiple harmonic frequency points. The process includes: for the same abnormal branch, obtaining the target admittance correction amount corresponding to each configurable electrical unit at multiple harmonic frequency points, and arranging the target admittance correction amounts according to the harmonic frequency points to form a multi-frequency admittance correction sequence for the configurable electrical unit; performing sign consistency and amplitude deviation analysis on the multi-frequency admittance correction sequence; if the target admittance correction amounts corresponding to different harmonic frequency points are inconsistent in the sign direction, or if their amplitude differences exceed a preset cross-frequency deviation threshold, then the configurable electrical unit is... Electrical units are marked as having cross-frequency admittance correction conflicts. For electrical units marked as having cross-frequency admittance correction conflicts, under the condition that the overall equivalent admittance deviation of the constrained abnormal branch does not increase, the multi-frequency admittance correction sequence is subjected to cross-frequency constraint reshaping. The cross-frequency constraint reshaping is completed by increasing the constraint priority of the admittance correction amount corresponding to the harmonic frequency point with a high contribution to the admittance deviation of the abnormal branch, and simultaneously compressing the adjustment range of the admittance correction amount corresponding to the other harmonic frequency points. After the cross-frequency constraint reshaping is completed, the effective admittance correction amount of each configurable electrical unit at each harmonic frequency point is output as the constraint input for the calculation process of electrical parameter adjustment amount.

7. The method for harmonic suppression of power distribution cabinets based on multi-source data fusion according to claim 6, characterized in that: Step 4, in the process of constraining the electrical parameter adjustment amount based on the effective admittance correction, applies continuity and boundary constraints to the admittance change trajectory during the electrical parameter adjustment process to limit the adjustment path. The process includes: obtaining the admittance change trajectory corresponding to the change from the current electrical parameter state to the target electrical parameter state of each configurable electrical unit at each harmonic frequency point, and representing the admittance change trajectory as a discrete admittance sequence that progresses with the parameter change step size; calculating the change amplitude between adjacent admittance states in the discrete admittance sequence segment by segment; if the change amplitude between adjacent admittance states exceeds the preset admittance change upper limit threshold at the corresponding harmonic frequency point, it is determined that the electrical parameter adjustment path has a risk of admittance abrupt change; for the electrical parameter adjustment path determined to have a risk of admittance abrupt change, the parameter change step size is segmented and reconstructed, by reducing the single parameter change amplitude and increasing the number of parameter change segments, so that the change amplitude between adjacent admittance states is limited to the admittance change upper limit threshold; after completing the segmented reconstruction process, a constrained parameter adjustment trajectory is generated based on the reconstructed parameter change step size sequence, and the constrained parameter adjustment trajectory is used as the path constraint for performing electrical parameter adjustment.

8. The method for harmonic suppression in a distribution cabinet based on multi-source data fusion according to claim 1, characterized in that: In step 5, during the operation of the distribution cabinet, periodic admittance state change triggering conditions are set for steps one to three. The triggering conditions include at least a change in the abnormal branch set or a change in the equivalent admittance parameter of any abnormal branch at the target harmonic frequency point relative to the previous operating cycle exceeding a preset admittance change threshold. Only when the triggering conditions are met will parameter configuration instructions for the configurable electrical units be generated based on the updated abnormal branches and corresponding electrical parameter adjustment amounts.

9. A method for harmonic suppression in a distribution cabinet based on multi-source data fusion according to claim 1, characterized in that: In step 6, during parameter adjustment, the parameter adjustment of the same configurable electrical unit at different harmonic frequency points is differentiated by constructing a frequency-related parameter mapping relationship. The process includes: obtaining the equivalent admittance correction requirements of the configurable electrical unit in each abnormal branch at each target harmonic frequency point, and representing the equivalent admittance correction requirements as a set of admittance targets indexed by harmonic frequency; based on the admittance target set, establishing a frequency-related parameter mapping model for the configurable electrical unit, mapping the admittance targets at different harmonic frequency points to the corresponding frequency-related electrical parameter components inside the electrical unit, wherein each parameter component is independent of each other in electrical structure and is not coupled to each other during adjustment; during the parameter configuration command execution stage, adjusting each frequency-related electrical parameter component of the configurable electrical unit according to the frequency-related parameter mapping model, so that the electrical unit presents the corresponding equivalent admittance state at each target harmonic frequency point.

10. A method for suppressing harmonics in a distribution cabinet based on multi-source data fusion according to claim 1, characterized in that: In step 6, during the adjustment of frequency-related electrical parameters of configurable electrical units in abnormal branches, frequency-layered adjustment timing constraints are used to expand and process the parameter configuration instructions. The process includes: prioritizing the frequency-related electrical parameter components based on the equivalent admittance deviation corresponding to each target harmonic frequency point to form a parameter adjustment sequence divided by harmonic frequency level, wherein the parameter component with the lower harmonic frequency has a higher adjustment priority in the parameter adjustment sequence; when executing the parameter adjustment sequence, an independent adjustment step size upper limit and intermediate stability judgment interval are set for the parameter components of each frequency level; after the adjustment of the parameter components of the current frequency level is completed, it is detected whether the equivalent admittance change of the corresponding abnormal branch at that harmonic frequency point enters the preset stability interval; if the detection result meets the stability interval constraint, the parameter component adjustment of the next frequency level is continued; if the stability interval constraint is not met, the parameter components of the current frequency level are backtracked and corrected, and the adjustment process of the frequency level is re-entered after the backtracking correction is completed.

Images