Method for suppressing no-load closing impulse current of transformer

Abstract

The invention discloses a method for suppressing no-load closing impact current of a transformer. The method comprises the following steps: detecting load characteristics and current waveform of a power grid before closing; based on the detected load characteristics and the current waveform, phase correction is carried out, and closing parameters are adjusted in real time to control the impact current; and in the switching-on process, the phase is adjusted based on load characteristics, and multi-point synchronous control is performed in stages. According to the transformer no-load closing control method provided by the invention, by dynamically analyzing the load characteristics and the current phase information, a proper phase angle can be accurately selected before closing, optimal control of the current waveform is realized, and the impact current in the closing process is effectively reduced. Compared with a traditional method, parameters such as the closing angle, the trigger delay and the power factor are adaptively adjusted through real-time data feedback, so that the system can keep the optimal closing state under various load conditions, the stability of a power grid is improved, and the service life of equipment is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of suppressing transformer no-load technology, and in particular to a method for suppressing transformer no-load switching impact current. Background Art

[0002] In the power system, the no-load closing operation of the transformer will cause a large inrush current. Especially during the startup process of a large transformer, the instantaneous current peak may exceed the rated current of the equipment by several times, resulting in system voltage fluctuations, increased equipment losses, and even malfunction of protection equipment. Traditional closing control methods mostly rely on fixed-angle closing or simple delay control, which fails to fully consider the dynamic changes of the grid load, the fluctuation of the power factor and the phase characteristics, making it difficult to effectively suppress the inrush current. With the increasing requirements for stability and efficiency of the power system, a dynamic and intelligent closing control method is urgently needed. By analyzing the load characteristics and current phase information in real time, various parameters of the closing process can be optimized to reduce the impact of the inrush current on the grid. Summary of the invention

[0003] In view of the above existing problems, the present invention is proposed.

[0004] Therefore, the present invention provides a method for suppressing the impact current of transformer no-load closing, aiming to solve the impact current problem caused by the sudden increase of instantaneous current during the no-load closing process of the transformer, and realizes precise control of the current by real-time monitoring and dynamic adjustment of the closing angle, phase and trigger delay. The present invention proposes a closing control method based on load characteristics, power factor and phase information, which can analyze the current waveform before closing, select the appropriate closing angle, and make the operation occur near the trough or zero crossing of the current waveform, thereby reducing the instantaneous current change. At the same time, through the dynamic fine-tuning of multiple nodes and the real-time adjustment of the power factor, the current increment is gradually controlled to reduce the current impact on the system. This method realizes the refined regulation of the closing process through innovative mathematical models and real-time data feedback.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution, a method for suppressing the no-load switching inrush current of a transformer, comprising:

[0006] Detect the load characteristics and current waveform of the power grid before closing the switch;

[0007] Based on the detected load characteristics and current waveform, phase correction is performed and closing parameters are adjusted in real time to control the inrush current;

[0008] During the closing process, the phase is adjusted based on the load characteristics and multi-point synchronous control is performed in stages.

[0009] As a preferred solution of the method for suppressing transformer no-load switching-on impact current described in the present invention, the detection of the load characteristics and current waveform of the power grid includes real-time sampling of the power grid state to obtain data on the current voltage, current, power factor and load fluctuation rate, wherein the data collection of voltage and current is performed by a sensor installed at the input end of the transformer, the power factor is calculated based on the phase difference between the voltage and the current, and is calculated in real time by a calculation module in the control system to obtain the load properties of the power grid and the lagging or leading state of the current, and the load fluctuation rate is calculated by comparing and analyzing historical data with current data to determine the short-term volatility and stability of the load;

[0010] After data collection is completed, the impact current prediction analysis is performed based on the collected load characteristic data, and the collected voltage, current, power factor and load fluctuation rate parameters are input into the model to predict the impact current of the upcoming closing through the preset algorithm. The preset algorithm is a specific prediction algorithm obtained through big data training, or a mathematical model that combines historical closing data with the current state.

[0011] As a preferred solution of the method for suppressing the no-load closing impact current of the transformer described in the present invention, the phase correction includes sampling the current waveform, obtaining the current closing phase angle, and adjusting the phase angle of the waveform based on a nonlinear phase correction algorithm so that the closing is performed at a suitable phase angle.

[0012] As a preferred solution of the method for suppressing the no-load closing inrush current of the transformer described in the present invention, wherein: the adjusting the closing parameters to control the inrush current includes, after completing the phase correction, by predicting the inrush current value I based on the load characteristics inrush , dynamically adjust the closing angle and trigger delay parameters at the closing moment, and use the previously collected voltage, current, power factor and load fluctuation rate data to predict the impact current I that may be generated at the closing moment inrush , dynamically select the closing angle θc according to the impact current value to make it close to the ideal closing angle θ ideal , select the trough or zero position of the current waveform;

[0013] In order to coordinate with the closing angle adjustment, the control system sets a trigger delay to control the execution time of the closing operation. The trigger delay time t d The setting is based on the phase information of the current current waveform to ensure that the closing operation is performed at the corresponding set angle. The specific delay formula is: Where ω is the grid angular frequency, θ curr is the current instantaneous phase angle.

[0014] As a preferred solution of the method for suppressing transformer no-load closing impact current described in the present invention, wherein: the phase adjustment based on load characteristics includes, during the closing operation, collecting the instantaneous signal of the current in real time through the current sensor installed at the input end of the transformer, recording the current change trend at the moment of closing, and dynamically fine-tuning the closing angle and trigger delay after the control system receives these real-time feedback data; the closing process is divided into control nodes of multiple time periods, and each control node adjusts the closing parameters of the current node according to the instantaneous current feedback value collected in real time, so that the current change amplitude is kept within the preset threshold;

[0015] The system monitors the instantaneous rate of change of current at each node, and gradually adjusts the closing angle and triggering timing through the set adjustment algorithm. In each node, the system calculates the current change amplitude compared with the previous node, and adjusts the closing angle and triggering delay of the next node based on the change trend.

[0016] As a preferred solution of the method for suppressing transformer no-load closing impact current described in the present invention, wherein: the stepwise adjustment of the closing angle and the triggering timing includes, in the buffer closing process, the control system dynamically adjusts the subsequent closing time interval based on the real-time feedback information of the previous control node, specifically, each control node records the change trend of the instantaneous current during the closing operation, including the current increment and fluctuation of the current node, and feeds the data back to the control system, and the system calculates the actual current increment rate according to the feedback information, and compares it with the preset target increment rate;

[0017] If the actual increment deviates from the target value, the system will immediately adjust the trigger time interval of the next node to make the current increment tend to be stable. When the increment of the current node exceeds the preset value, the system will appropriately extend the next closing trigger time, otherwise it will shorten the time interval. Within each delay step, the system will recalculate the required trigger timing to maintain a consistent current increment.

[0018] As a preferred solution of the method for suppressing the no-load closing impact current of the transformer described in the present invention, the multi-point synchronous control in stages includes, during the closing operation, real-time detection of the power factor change of the power grid by sensors, and recording the change of the power factor PF(t) at the closing moment with time, wherein the real-time monitoring of the power factor includes collecting the phase difference between voltage and current, calculating the power factor at each moment, and dynamically tracking the load characteristics during the closing process.

[0019] As a preferred solution of the method for suppressing transformer no-load closing impact current described in the present invention, wherein: the multi-point synchronous control in stages includes, based on the detected power factor change value, the control system adjusts the power factor control parameters of the closing, when the power factor fluctuates significantly, the system will immediately correct the closing parameters to keep the current growth in the closing process within the set range, wherein the control system introduces a real-time adjustment amount δ to the power factor control parameters according to the set adjustment strategy PF , the adjustment amount is set based on the difference between the current power factor and the target power factor;

[0020] When the power factor is lower than the preset value, the system improves the power factor by reducing the lag angle of the load power factor and reduces the current surge at the initial stage of closing the switch; when the power factor gradually approaches the target value, the system reduces the adjustment amount.

[0021] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of a method for suppressing the inrush current of transformer no-load closing are implemented.

[0022] A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of a method for suppressing the inrush current of transformer no-load closing are implemented.

[0023] Beneficial effects of the present invention: The transformer no-load closing control method proposed in the present invention can accurately select the appropriate phase angle before closing by dynamically analyzing the load characteristics and current phase information, realize the optimization control of the current waveform, and effectively reduce the impact current during the closing process. Compared with traditional methods, the present invention uses real-time data feedback to adaptively adjust parameters such as closing angle, trigger delay and power factor, so that the system can maintain the optimal closing state under various load conditions, thereby improving the stability of the power grid and the service life of the equipment. The innovative mathematical model of the present invention ensures the efficiency and accuracy of the regulation process, provides a more stable and safer power transmission method, and meets the needs of modern power systems for intelligence and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figure 1 A schematic flow chart of a method for suppressing transformer no-load switching inrush current provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0030] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Example 1, reference Figure 1, which is the first embodiment of the present invention, provides a method for suppressing transformer no-load closing inrush current, comprising:

[0033] S1: Detect the load characteristics and current waveform of the power grid before closing the circuit breaker.

[0034] S2: Based on the detected load characteristics and current waveform, phase correction is performed and closing parameters are adjusted in real time to control the inrush current.

[0035] S3: During the closing process, the phase is adjusted based on the load characteristics and multi-point synchronous control is performed in stages.

[0036] The detection of the load characteristics and current waveform of the power grid includes real-time sampling of the power grid state to obtain data on the current voltage, current, power factor and load fluctuation rate, wherein the data collection of voltage and current is performed by a sensor installed at the input end of the transformer, the power factor is calculated based on the phase difference between the voltage and the current, and is calculated in real time by a calculation module in the control system to obtain the load properties of the power grid and the lagging or leading state of the current, and the load fluctuation rate is calculated by comparing and analyzing historical data with current data to determine the short-term volatility and stability of the load;

[0037] After data collection is completed, the impact current prediction analysis is performed based on the collected load characteristic data, and the collected voltage, current, power factor and load fluctuation rate parameters are input into the model to predict the impact current of the upcoming closing through the preset algorithm. The preset algorithm is a specific prediction algorithm obtained through big data training, or a mathematical model that combines historical closing data with the current state.

[0038] Specifically, voltage V(t) and current I(t) are the basic electrical parameters at the input of the transformer, which are collected by sensors and recorded in the control system in the form of real-time sampling to capture the instantaneous state of the load. Sampling frequency f s It should be higher than the standard frequency of the power grid to ensure the integrity of high frequency details.

[0039] Based on the collected voltage and current phase difference θ(t), calculate the current power factor PF(t). The power factor formula is:

[0040] PF(t)=cos(θ(t))

[0041] Among them, θ(t) is obtained by calculating the phase difference between voltage and current.

[0042] Load fluctuation rateσ L It is expressed by the difference between the current data and the historical average. The specific calculation formula is:

[0043]

[0044] Among them, L k Indicates the load power value of each sampling, is the historical power average, and n is the total number of samples. The load fluctuation rate is used to characterize the fluctuation of load in a short period of time, thereby increasing the adaptability of prediction in the model.

[0045] In order to generate the predicted value of closing inrush current based on the above characteristics, an improved adaptive inrush current prediction model is introduced. Combined with the load characteristic data, a piecewise prediction formula is established based on nonlinear regression analysis, which is particularly suitable for highly fluctuating loads.

[0046] Based on voltage V(t), current I(t), power factor PF(t) and load fluctuation σ L , define the closing inrush current I inrush The prediction formula is:

[0047]

[0048] Among them, α, β, and γ are adjustment parameters, which are adaptively updated by the system based on historical data, and The term is used to weight the nonlinear characteristics of the power factor when it is close to zero. The dynamic effect of load fluctuation is taken into account.

[0049] In order to enhance the flexibility of the model, the recursive least squares method (RLS) is introduced to adjust the parameters α, β and γ for real-time adjustment so that the model can adapt to different load conditions. The adaptive adjustment formula is:

[0050]

[0051] Among them, η is the learning rate, I actual is the actual measured impulse current value, (I actual -I inrush ) is the model error.

[0052] θ c =θ optimal -κ·I inrush

[0053] Among them, θ optimal is the optimal closing angle preset in the system, and κ is the correction coefficient of the inrush current, which is used to adjust the closing angle to control the magnitude of the inrush current.

[0054] In the inrush current prediction model and closing parameter optimization process of the present invention, the following formula characters are involved: V(t) represents the voltage value collected at time t, in volts (V). I(t) represents the current value collected at time t, in amperes (A). PF(t) represents the power factor at time t, dimensionless, calculated by the phase difference between voltage and current, and used to characterize the load characteristics of the power grid. θ(t) represents the phase difference between voltage and current at time t, in radians (rad), and is used to calculate the phase relationship of the power factor. σ L Indicates the load fluctuation rate in square watts (W 2 ), calculated based on the variance of the load power data. k Indicates the load power value at the kth sampling time. Indicates the average load power over a period of time, in watts (W). n indicates the total number of samples, which is used in the calculation of load fluctuation rate. inrush Indicates the predicted closing inrush current value in ampere (A), which is generated based on the load characteristic data. The weighted term represents the power factor PF(t). The power factor is amplified nonlinearly by a sine function to adapt to the special situation when the power factor is close to zero. Indicates the square root of the load fluctuation rate. actual Represents the actual measured closing impact current value, in ampere (A). η represents the learning rate in the recursive least squares method, which is used to control the step size of adaptive parameter adjustment. θ c Indicates the recommended closing angle in radians (rad), based on the predicted inrush current I inrush Calculate. optimal It indicates the optimal closing angle preset in the system, in radians (rad), which is the angle selected to achieve the lowest inrush current. κ indicates the inrush current correction factor.

[0055] The phase correction includes sampling the current waveform to obtain the current closing phase angle, and adjusting the phase angle of the waveform based on a nonlinear phase correction algorithm so that the closing is performed at a suitable phase angle.

[0056] In order to achieve nonlinear phase correction, an improved nonlinear phase offset model is introduced to generate a suitable closing time according to the deviation between the current phase angle and the ideal phase angle. The mathematical formula of the model is as follows:

[0057] Ideal phase angle θ ideal The target closing angle is calculated based on the current waveform and power factor PF. The goal is to achieve the minimum inrush current, so θ is determined by the following formula ideal :

[0058] θideal =π-arccos(PF)

[0059] Among them, the power factor PF represents the phase relationship of the load, and π-arccos (PF) is used to determine the phase of the current waveform close to the zero point.

[0060] The deviation between the current phase angle and the ideal phase angle is defined as Δθ, that is:

[0061] Δθ=θ curr -θ ideal

[0062] When the deviation is not zero, a nonlinear function is introduced to perform phase shift to ensure that the closing state is close to the ideal state. The nonlinear correction formula uses a hyperbolic tangent function for adjustment, so that the adjustment amount has the characteristics of smooth transition:

[0063] θ shift =λ·tanh(k·Δθ)

[0064] Among them, λ is the correction coefficient, which controls the amplitude of the phase offset; k is the smoothing coefficient, which adjusts the speed of deviation correction.

[0065] Closing time t close The final closing angle θ obtained after phase correction final Calculate, where:

[0066] θ final =θ curr -θ shift

[0067] The closing time can be determined by the following formula:

[0068]

[0069] Where ω is the angular frequency of the current waveform (in radians per second).

[0070] The adjusting of the closing parameters to control the inrush current includes, after completing the phase correction, using the inrush current value I predicted based on the load characteristics inrush , dynamically adjust the closing angle and trigger delay parameters at the closing moment, and use the previously collected voltage, current, power factor and load fluctuation rate data to predict the impact current I that may be generated at the closing moment inrush , dynamically select the closing angle θc according to the impact current value to make it close to the ideal closing angle θ ideal , select the trough or zero position of the current waveform;

[0071] Dynamic calculation of the valley or zero crossing point is performed through phase detection data, and the closing angle θ is set based on the phase information of the current current waveform. cis the zero crossing point or trough angle of the current waveform. Assume that the current waveform I(t) = I max sin(ωt+φ), then the zero crossing angle is: θ zero =-φ; trough angle: θ valley =π-φ.

[0072] Select the optimal closing angle θ ideal To minimize the instantaneous current, the closing angle is as close to the zero crossing point or the valley position as possible. curr , define the target closing angle as:

[0073] θ ideal =θ zero +α·(θ valley -θ zero )

[0074] Among them, α is the dynamic adjustment coefficient, and its value range is 0≤α≤1, which is used to adjust the optimal closing angle between the zero crossing point and the trough position.

[0075] According to the load fluctuation, α is adjusted in real time to adapt the closing angle to different load conditions. The dynamic update formula of α is defined as:

[0076] α=tanh(β·Δθ)

[0077] Where Δθ=θ ideal -θ curr is the deviation between the current phase angle and the ideal closing angle, and β is the sensitivity coefficient. This formula uses the tanh function to achieve smooth dynamic adjustment, so that the closing angle moves between the zero crossing point and the trough.

[0078] After calculating the appropriate closing angle θ c After that, determine the closing trigger time t close :

[0079]

[0080] Where, ω is the angular frequency of the power grid, θ curr is the current instantaneous phase angle, ensuring that the closing operation is performed at a precise phase angle.

[0081] In order to coordinate with the closing angle adjustment, the control system sets a trigger delay to control the execution time of the closing operation. The trigger delay time t d The setting is based on the phase information of the current current waveform to ensure that the closing operation is performed at the corresponding set angle. The specific delay formula is: Where ω is the grid angular frequency, θ curr is the current instantaneous phase angle.

[0082] The phase adjustment based on load characteristics includes, during the closing operation, collecting the instantaneous signal of the current in real time through the current sensor installed at the input end of the transformer, recording the current change trend at the closing moment, and dynamically fine-tuning the closing angle and trigger delay after the control system receives these real-time feedback data; the closing process is divided into control nodes of multiple time periods, and each control node adjusts the closing parameters of the current node according to the instantaneous current feedback value collected in real time, so that the current change amplitude remains within a preset threshold;

[0083] The system monitors the instantaneous rate of change of current at each node, and gradually adjusts the closing angle and triggering timing through the set adjustment algorithm. In each node, the system calculates the current change amplitude compared with the previous node, and adjusts the closing angle and triggering delay of the next node based on the change trend.

[0084] The stepwise adjustment of the closing angle and the triggering timing includes that, during the buffer closing process, the control system dynamically adjusts the subsequent closing time interval based on the real-time feedback information of the previous control node. Specifically, each control node records the changing trend of the instantaneous current during the closing operation, including the current increment and fluctuation of the current at the current node, and feeds the data back to the control system. The system calculates the actual current increment rate based on the feedback information and compares it with the preset target increment rate.

[0085] If the actual increment deviates from the target value, the system will immediately adjust the trigger time interval of the next node to make the current increment tend to be stable. When the increment of the current node exceeds the preset value, the system will appropriately extend the next closing trigger time, otherwise it will shorten the time interval. Within each delay step, the system will recalculate the required trigger timing to maintain a consistent current increment.

[0086] The multi-point synchronous control in stages includes, during the closing operation, real-time detection of the power factor change of the power grid by sensors, and recording the change of the power factor PF(t) at the closing moment with time, wherein the real-time monitoring of the power factor includes collecting the phase difference between voltage and current, calculating the power factor at each moment, and dynamically tracking the load characteristics during the closing process.

[0087] The multi-point synchronous control in stages includes: based on the detected power factor change value, the control system adjusts the power factor control parameters of the closing switch; when the power factor fluctuates significantly, the system will immediately correct the closing switch parameters to keep the current growth in the closing process within the set range; wherein the control system introduces a real-time adjustment amount δ to the power factor control parameters according to the set adjustment strategy PF , the adjustment amount is set based on the difference between the current power factor and the target power factor;

[0088] When the power factor is lower than the preset value, the system improves the power factor by reducing the lag angle of the load power factor and reduces the current surge at the initial stage of closing the switch; when the power factor gradually approaches the target value, the system reduces the adjustment amount.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0090] Example 2

[0091] The second embodiment of the present invention is different from the previous embodiment in that:

[0092] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0093] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0094] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0095] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0096] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0097] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for suppressing transformer no-load closing inrush current, characterized in that: include, Detect the load characteristics and current waveform of the power grid before closing the switch; Based on the detected load characteristics and current waveform, phase correction is performed and closing parameters are adjusted in real time to control the inrush current; During the closing process, the phase is adjusted based on the load characteristics and multi-point synchronous control is performed in stages.

2. A method for suppressing transformer no-load switching inrush current as claimed in claim 1, characterized in that: The detection of the load characteristics and current waveform of the power grid includes real-time sampling of the power grid state to obtain data on the current voltage, current, power factor and load fluctuation rate, wherein the data collection of voltage and current is performed by a sensor installed at the input end of the transformer, the power factor is calculated based on the phase difference between the voltage and the current, and is calculated in real time by a calculation module in the control system to obtain the load properties of the power grid and the lagging or leading state of the current, and the load fluctuation rate is calculated by comparing and analyzing historical data with current data to determine the short-term volatility and stability of the load; After data collection is completed, the impact current prediction analysis is performed based on the collected load characteristic data, and the collected voltage, current, power factor and load fluctuation rate parameters are input into the model to predict the impact current of the upcoming closing through the preset algorithm. The preset algorithm is a specific prediction algorithm obtained through big data training, or a mathematical model that combines historical closing data with the current state.

3. A method for suppressing transformer no-load switching inrush current as claimed in claim 2, characterized in that: The phase correction includes sampling the current waveform to obtain the current closing phase angle, and adjusting the phase angle of the waveform based on a nonlinear phase correction algorithm so that the closing is performed at a suitable phase angle.

4. A method for suppressing transformer no-load switching inrush current as claimed in claim 3, characterized in that: The adjusting of closing parameters to control the inrush current comprises: After completing the phase correction, the impact current value I inrush , dynamically adjust the closing angle and trigger delay parameters at the closing moment, and use the previously collected voltage, current, power factor and load fluctuation rate data to predict the impact current I that may be generated at the closing moment inrush , dynamically select the closing angle θc according to the impact current value to make it close to the ideal closing angle θ ideal , select the trough or zero position of the current waveform; In order to coordinate with the closing angle adjustment, the control system sets a trigger delay to control the execution time of the closing operation. The trigger delay time t d The setting is based on the phase information of the current current waveform to ensure that the closing operation is performed at the corresponding set angle. The specific delay formula is: Where ω is the grid angular frequency, θ curr is the current instantaneous phase angle.

5. A method for suppressing transformer no-load switching inrush current as claimed in claim 4, characterized in that: The phase adjustment based on load characteristics includes, during the closing operation, collecting the instantaneous signal of the current in real time through the current sensor installed at the input end of the transformer, recording the current change trend at the closing moment, and dynamically fine-tuning the closing angle and trigger delay after the control system receives these real-time feedback data; the closing process is divided into control nodes of multiple time periods, and each control node adjusts the closing parameters of the current node according to the instantaneous current feedback value collected in real time, so that the current change amplitude remains within a preset threshold; The system monitors the instantaneous rate of change of current at each node, and gradually adjusts the closing angle and triggering timing through the set adjustment algorithm. In each node, the system calculates the current change amplitude compared with the previous node, and adjusts the closing angle and triggering delay of the next node based on the change trend.

6. A method for suppressing transformer no-load switching inrush current as claimed in claim 5, characterized in that: The stepwise adjustment of the closing angle and the triggering timing includes that, during the buffer closing process, the control system dynamically adjusts the subsequent closing time interval based on the real-time feedback information of the previous control node. Specifically, each control node records the changing trend of the instantaneous current during the closing operation, including the current increment and fluctuation of the current at the current node, and feeds the data back to the control system. The system calculates the actual current increment rate based on the feedback information and compares it with the preset target increment rate. If the actual increment deviates from the target value, the system will immediately adjust the trigger time interval of the next node to make the current increment tend to be stable. When the increment of the current node exceeds the preset value, the system will appropriately extend the next closing trigger time, otherwise it will shorten the time interval. Within each delay step, the system will recalculate the required trigger timing to maintain a consistent current increment.

7. A method for suppressing transformer no-load switching inrush current as claimed in claim 6, characterized in that: The multi-point synchronous control in stages includes, during the closing operation, real-time detection of the power factor change of the power grid by sensors, and recording the change of the power factor PF(t) at the closing moment with time, wherein the real-time monitoring of the power factor includes collecting the phase difference between voltage and current, calculating the power factor at each moment, and dynamically tracking the load characteristics during the closing process.

8. A method for suppressing transformer no-load switching inrush current as claimed in claim 7, characterized in that: The multi-point synchronous control in stages includes: Based on the detected power factor change value, the control system adjusts the power factor control parameters of the closing circuit. When the power factor fluctuates significantly, the system will immediately correct the closing parameters to keep the current growth during the closing process within the set range. The control system introduces a real-time adjustment amount δ to the power factor control parameters according to the set adjustment strategy. PF , the adjustment amount is set based on the difference between the current power factor and the target power factor; When the power factor is lower than the preset value, the system improves the power factor by reducing the lag angle of the load power factor and reduces the current surge at the initial stage of closing the switch; when the power factor gradually approaches the target value, the system reduces the adjustment amount.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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