Analog signal preprocessing system and method for suppressing magnetizing inrush current

Abstract

The invention provides an analog signal preprocessing system and method for suppressing excitation inrush current, and the method comprises the steps: obtaining an external analog signal through a signal capturing unit, carrying out the timing sampling of the analog signal through a signal sampling unit, converting the analog signal into a digital signal through an analog-to-digital conversion unit, and storing the digital signal in a data storage unit; the digital signal reverse mode conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relation between the stored timestamp and the signal strength; the signal time delay unit ensures that the time point of analog signal recovery is consistent with the time required for signal acquisition and conversion, and the timestamp control unit ensures that the time sequences of the analog signal and the recovery signal are consistent; and the preprocessed analog signal is output to the A / D conversion signal module through the signal reconstruction output unit and is converted into a digital signal to be transmitted to the logic judgment module, and according to a set standard, if the signal shows that the magnetizing inrush current is abnormal, an alarm is given to control a transformer to be switched on, and the magnetizing inrush current is inhibited and eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal processing, and more specifically, relates to an analog signal preprocessing system and method for suppressing excitation inrush current. Background Art

[0002] In the power system, the transformer is one of the important electrical equipment, which is widely used in power conversion, transmission and distribution. However, during the normal operation of the transformer, especially when closing the switch, a phenomenon called excitation inrush current will occur, which may have a serious impact on the transformer's protection system, control system and the safe and stable operation of the power grid. Excitation inrush current refers to the short-term instantaneous current fluctuation during the magnetization process of the transformer core. It usually occurs when the transformer is closed or re-commissioned. Due to the high amplitude and instantaneous nature of the excitation inrush current, it may interfere with the protection relay, control system and other equipment in the power grid, resulting in malfunction or unnecessary outage. For example, the protection relay often misjudges it as a fault current and starts the circuit breaker without an actual fault, which will cause the transformer to fail to operate and affect the normal operation of the power system.

[0003] To deal with the malfunction problem caused by transformer excitation inrush current, especially in the process of closing control and triggering of protection relays, it is particularly important to pre-process the analog signal to improve the signal quality. The current waveform of the excitation inrush current is usually very short and strong, so if there is no effective signal processing, the protection relay may misjudge it as a fault current, resulting in malfunction, such as circuit breaker tripping, including the following situations:

[0004] 1. Increase the noise interference of the system: In wireless communication systems, signals may be affected by noise, interference or attenuation during transmission. If the signal is not pre-processed, especially if a delay or acquisition unit is not used to reduce the interference of the signal, additional noise may be introduced into the signal.

[0005] 2. Reduce system stability: Excitation inrush current usually causes instantaneous current fluctuations and may cause a drop in power supply voltage or instantaneous overload of equipment. If the analog signal in the wireless communication system is not properly processed, signal interference may cause unstable response of electrical equipment.

[0006] 3. Cause equipment failure or damage: The excitation inrush current will not only affect the normal operation of the equipment, but may also cause equipment failure or damage. Since the transmission of analog signals has not undergone effective anti-interference processing, such as synchronous grouping and signal delay, these disturbances may aggravate the current overload caused by the inrush current.

[0007] 4. Reduce the anti-interference ability of communication signals: If appropriate pre-processing measures are not taken in the wireless communication system to prevent external interference, such as through delay units, acquisition units, etc., the analog signal may be subject to a wide range of interference, especially under the action of excitation surge current, the instantaneous high current generated will cause serious disturbances to the signal. Summary of the invention

[0008] In order to solve the deficiencies in the prior art, the present invention provides an analog signal preprocessing system and method for suppressing excitation inrush current, which accurately collects, processes and restores the voltage, current and other signals generated when the transformer is closed, ensuring that the system can still accurately detect the true characteristics of the grid voltage and the transformer excitation inrush current when subjected to electromagnetic interference, noise, distortion or other external influences, thereby avoiding malfunctions caused by signal distortion or erroneous judgment.

[0009] The present invention adopts the following technical solution.

[0010] A first aspect of the present invention provides an analog signal preprocessing system for suppressing excitation inrush current, comprising:

[0011] Analog signal processing output module, A / D conversion signal module, logic judgment module and control closing module;

[0012] The analog signal processing output module is used to perform signal modulation processing on the input analog signal and output the processed analog signal;

[0013] The A / D conversion signal module is used to receive the processed analog signal and convert it into a digital signal;

[0014] The logic judgment module is used to perform logic judgment and analysis on the converted digital signal, determine whether there is an abnormal excitation inrush current according to the set standard, and make corresponding response decisions;

[0015] The control closing module is used to control the closing operation of the transformer to suppress the excitation inrush current according to the analysis result of the logic judgment unit.

[0016] Optionally, the analog signal processing output module includes a signal capture unit, a signal sampling unit, an analog-to-digital conversion unit, a data storage unit, a digital signal reverse conversion unit, a signal delay unit, a timestamp control unit, and a signal reconstruction output unit;

[0017] The signal capture unit is responsible for directly acquiring the original signal sent by the transformer bus transmitting end;

[0018] The signal sampling unit is used to perform regular sampling of the original signal transmitted from the signal capturing unit through periodic time intervals;

[0019] The analog-to-digital conversion unit is used to convert the signal strength obtained by each sampling into digital data, and match the digital data with the timestamp of the corresponding sampling;

[0020] The data storage unit is used to store the collected signal data, including the timestamp information and signal strength data of each collection;

[0021] The digital signal reverse conversion unit is used to reversely convert the digital signal into the original analog signal according to the timestamp stored in the data storage unit and the signal strength data corresponding to the timestamp;

[0022] The signal delay unit is used to perform delay processing on the analog signal to ensure that the delay span is synchronized with the time of signal sampling and digital signal reverse conversion;

[0023] The timestamp control unit is used to provide timestamp control for each unit to ensure that the timestamp of the received original signal is consistent with the timestamp of the original analog signal reversely converted by the digital signal reverse conversion unit;

[0024] The signal reconstruction output unit is used to output the inverted and restored original analog signal.

[0025] Optionally, the signal sampling unit includes a first timestamp data sampling component, a second timestamp data sampling component and a third timestamp data sampling component, each component is responsible for respectively collecting the signal strength of the analog signal and synchronously transmitting the collected data to the receiving end;

[0026] The timestamp data sampling first component is used to obtain signal data of the analog signal at the (3n+1)T0 timestamp;

[0027] The timestamp data sampling second component is used to obtain signal data of the analog signal at the (3n+2)T0 timestamp;

[0028] The timestamp data sampling third component is used to obtain signal data of the analog signal at the (3n+3)T0 timestamp.

[0029] Optionally, the analog-to-digital conversion unit includes a signal grouping unit and an inverse analysis and restoration component;

[0030] The signal grouping unit is used to split the signal into three signal clusters with the same timestamp attribute;

[0031] The reverse parsing and recovery component is used to perform reverse recovery on the three groups of data that have been split and transmitted.

[0032] Optionally, the timestamp control unit includes a signal difference detection component, a signal merging component and a signal correction component;

[0033] The signal difference detection component is used to compare the received analog signal with the reverse-recovered analog signal, and identify the error generated in the recovery process by comparing the two;

[0034] The signal merging component is used to merge the directly received signal and the reversely recovered analog signal, and eliminate the errors caused by the interference and recovery process by superimposing and merging the two, and finally obtain a waveform curve that is highly overlapped with the waveform of the original signal;

[0035] The signal correction component is used to further analyze and process the superimposed and combined signals to eliminate errors and deviations caused by interference with the received signals and deviations generated during the reverse recovery process.

[0036] A second aspect of the present invention provides an analog signal preprocessing method for suppressing excitation inrush current, which is run on an analog signal preprocessing system for suppressing excitation inrush current according to the first aspect of the present invention, and comprises the following steps:

[0037] The external analog signal is acquired through the signal capture unit and collected by the signal sampling unit. The collection process is carried out at fixed time intervals.

[0038] The collected analog signal is converted into a digital signal through the analog-to-digital conversion unit and stored in the data storage unit;

[0039] After the data storage is completed, the digital signal reverse conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relationship between the timestamp and the signal strength based on the stored data;

[0040] The signal delay unit is used to delay the signal appropriately to ensure that the time point of analog signal recovery is consistent with the time required for signal acquisition and conversion. The timestamp control unit coordinates the work of each module to ensure the timing of the analog signal and the recovery signal is consistent;

[0041] The pre-processed and restored analog signal is outputted through the signal reconstruction output unit, and the A / D conversion signal module receives the pre-processed analog signal outputted by the signal reconstruction output unit and converts it into a digital signal;

[0042] The converted digital signal is transmitted to the logic judgment module, which monitors and analyzes the signal in real time. According to the set standard, if the signal shows abnormal excitation inrush current, an alarm is issued, and the control closing module controls the transformer to close according to the judgment result to suppress and eliminate the excitation inrush current.

[0043] Optionally, in the method, collecting data using a signal sampling unit is specifically:

[0044] The signal sampling unit samples the original signal transmitted by the signal capture unit at a periodic interval. The sampling function is recorded as s(t). The original analog signal is a continuous-time signal, recorded as f(t). Then:

[0045] f s (t) = f(t)s(t)

[0046] Among them, f s (t) represents the time domain function after sampling, and Fourier transform is performed on it to convert the time domain function into the corresponding spectrum function:

[0047]

[0048] Among them, F s (t) represents the sampled spectral function, F(t) is the frequency domain expression of f(t), and S(t) is the frequency domain expression of s(t).

[0049] Optionally, the digital signal reverse conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relationship between the timestamp and the signal strength according to the stored data:

[0050] The data collected at different time nodes are recombined and processed through the inverse analysis algorithm so that they are completely aligned in time sequence, thereby restoring the original analog signal;

[0051] The inverse analysis algorithm formula is:

[0052]

[0053] Among them, w(t) represents the sampled spectrum function F s (t) is a continuous function formed after inverse analysis.

[0054] Optionally, the method further includes combining the directly received original signal and the reversely recovered analog signal, and eliminating errors caused by interference and recovery processes by superimposing and combining the two, specifically:

[0055]

[0056] Among them, h t It represents the function obtained by superimposing and merging the restored continuous signal with the original signal to form a new combined signal.

[0057] Optionally, the error includes:

[0058] When the original impulse signal acquired is disturbed by error, it is expressed as:

[0059]

[0060] When the impact signal is reversely recovered, the function error is expressed as:

[0061]

[0062] At this time, the new signal obtained by superimposing the restored signal and the error interference signal is expressed as:

[0063]

[0064] Through this superposition, the errors in the signal caused by interference and recovery process cancel each other out, making the final signal more consistent with the original analog signal h(t) waveform.

[0065] The beneficial effect of the present invention is that, compared with the prior art,

[0066] 1) During the process of transformer closing and excitation inrush current control, the analog signal processing system effectively reduces the impact of external noise and interference on the signal through a variety of technical means, such as signal acquisition, filtering, timing synchronization, and signal recovery, ensuring accurate detection and control of excitation inrush current. This can not only improve the reliability of transformer commissioning, but also prevent malfunction of protection relays caused by misjudgment, thereby ensuring the safety of substation equipment and the stable operation of the power system;

[0067] 2) Collect the analog signal and ensure that the time interval of each collection is equal. This equal-interval collection method helps to ensure the consistency of signal data and provide a controllable data stream for subsequent processing. The signal delay unit is used to perform delay processing on the analog signal to ensure that the delay span is synchronized with the time of signal sampling and digital signal reverse conversion. The purpose of this delay processing is to ensure the synchronization of signal timing of different modules, thereby avoiding signal recovery errors or errors caused by inconsistent timing;

[0068] 3) The system splits the original analog signal into three groups of timing signals and transmits them separately, and then restores a signal close to the original waveform through reverse drawing technology at the receiving end. Although this method has certain errors, it greatly reduces the loss caused by signal interference and makes the recovered signal as close to the original signal as possible, thereby improving the robustness and recovery accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 The present invention is a flowchart of a method for preprocessing an analog signal for suppressing an excitation inrush current. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0071] like Figure 1 As shown, embodiment 1 of the present invention provides an analog signal preprocessing system for suppressing excitation inrush current, comprising: an analog signal processing output module, an A / D conversion signal module, a logic judgment module, and a control closing module;

[0072] The analog signal processing output module is used to perform signal modulation processing on the input analog signal and output the processed analog signal;

[0073] The A / D conversion signal module is used to receive the processed analog signal and convert it into a digital signal;

[0074] The logic judgment module is used to perform logic judgment and analysis on the converted digital signal, determine whether there is an abnormal excitation inrush current according to the set standard, and make corresponding response decisions;

[0075] The control closing module is used to control the closing operation of the transformer to suppress the excitation inrush current according to the analysis result of the logic judgment unit.

[0076] Further preferably, the analog signal processing output module includes a signal capture unit, a signal sampling unit, an analog-to-digital conversion unit, a data storage unit, a digital signal reverse conversion unit, a signal delay unit, a timestamp control unit and a signal reconstruction output unit;

[0077] The signal capture unit is responsible for directly acquiring the original signal sent by the transformer bus transmitting end;

[0078] The signal sampling unit is used to perform regular sampling of the original signal transmitted from the signal capturing unit at periodic intervals.

[0079] The original signal acquired by the signal capture unit in the embodiment of the present invention refers to a process that may not have been transmitted through a transmission line, wireless channel or other medium. In this case, the signal can be regarded as an original signal or a source signal, which has not been affected by external noise, interference or other distortion factors. At this stage, the signal basically maintains its original waveform; the signal sampling unit mainly ensures that the sampling of the original signal transmitted by the signal capture unit is equidistant in time through periodic time sampling, that is, the time interval for each signal sampling is the same, which is usually called timed sampling. The specific sampling rate needs to be selected according to the bandwidth or frequency of the signal. Based on the Nyquist theorem, in order to accurately collect a signal, its sampling rate must be at least twice the signal bandwidth, which is only used as an example.

[0080] Further preferably, the analog-to-digital conversion unit is used to convert the signal strength obtained by each sampling into digital data, and match the digital data with the timestamp of the corresponding sampling;

[0081] The data storage unit is used to store the collected signal data, including the timestamp information of each collection and the signal strength data.

[0082] The analog-to-digital conversion unit in the embodiment of the present invention converts the analog signal into discrete digital data through sampling and quantization processes. Sampling refers to collecting signals regularly in time, and quantization refers to converting the analog value obtained from each sampling into the closest digital value; the data storage unit includes signal strength and acquisition timestamp information, that is, the signal strength obtained from each sampling, in decibels (dB), usually representing the intensity of voltage, current, power, etc. and the timestamp of each sampling point, recording the exact time when the signal sampling occurs. The timestamp is usually provided by the system's clock unit to ensure the timing and consistency of the signal data.

[0083] Further preferably, the digital signal reverse conversion unit is used to reversely convert the digital signal into the original analog signal according to the timestamp stored in the data storage unit and the signal strength data corresponding to the timestamp;

[0084] The signal delay unit is used to perform delay processing on the analog signal to ensure that the delay span is synchronized with the time of signal sampling and digital signal reverse conversion.

[0085] The timestamp control unit is used to provide timestamp control for each unit to ensure that the timestamp of the received original signal is consistent with the timestamp of the original analog signal reversely converted by the digital signal reverse conversion unit;

[0086] The signal reconstruction output unit is used to output the reversed and restored original analog signal.

[0087] The core function of the data signal conversion unit in the embodiment of the present invention is to reverse-convert the stored digital signal (including the collected time information and signal strength data) to restore a waveform that is as close to the original analog signal as possible. This process needs to be implemented with the help of interpolation and digital-to-analog conversion (DAC) technology. By restoring the waveform of the signal, the system can effectively reconstruct a continuous analog signal, thereby realizing signal recovery, playback and further processing; the signal reconstruction output unit will reverse the restored original analog signal output, which means that after a series of collection, processing, conversion and synchronization, the system will restore a waveform that is as close to the original analog signal as possible, and output it to an external device or system through this unit. The unit is responsible for ensuring that the signal can still be as close to the original signal at the transmitting end as possible after interference, noise and other processing. Especially when the signal is affected by interference or noise, the function of the output unit is to minimize these effects and restore the original appearance of the signal as much as possible.

[0088] The original analog signal emitted from the transformer bus transmitting end is collected by a grouping unit and split into three signal clusters with the same timestamp attributes. The three split signal clusters and the original analog signal are transmitted to the receiving end synchronously. The three split signal clusters will be aggregated and merged at the receiving end to restore them to the original signal.

[0089] In the embodiment of the present invention, the system does not simply transmit the original analog signal, but divides it into three synchronous signal streams for transmission. Each signal stream contains the strength information of the original signal, usually in dB, and the timestamp attributes of these signals remain consistent, that is, they are completely synchronized in time. By splitting the signal into multiple streams, the system can reduce the interference that a single signal stream may receive. For example, if a signal stream is interfered with, other signal streams can still provide complete information about the signal, thereby improving the system's fault tolerance to interference. By transmitting three groups of signals at the same time, the receiving end can use this redundant information to perform error correction when merging, thereby restoring the original signal.

[0090] Further preferably, the signal sampling unit comprises a first timestamp data sampling component, a second timestamp data sampling component and a third timestamp data sampling component, each component is responsible for collecting the signal strength of the analog signal and synchronously transmitting the collected data to the receiving end;

[0091] The timestamp data sampling first component is used to obtain signal data of the analog signal at the (3n+1)T0 timestamp;

[0092] The timestamp data sampling second component is used to obtain signal data of the analog signal at the (3n+2)T0 timestamp;

[0093] The timestamp data sampling third component is used to obtain signal data of the analog signal at the (3n+3)T0 timestamp.

[0094] In the embodiment of the present invention, the first timestamp data sampling component is responsible for collecting the signal strength at a specific time point (3n+1)T0, where T0 may represent a basic time period, and 3nT0 represents a small time interval, which is usually used to improve the accuracy of signal acquisition; the second timestamp data sampling component is responsible for collecting the strength at the (3n+2)T0 time node, and relative to the first component collecting time node, it will have a time delay of one T0 period; the third timestamp data sampling component is responsible for collecting the strength at the (3n+3)T0 time node, and relative to the second component collecting time node, it will have a time delay of one T0 period; the original analog signal will be collected through the grouping unit and split into three groups of signals, corresponding to the signal data at the (3n+1)T0, (3n+2)T0 and (3n+3)T0 timestamps respectively, and these three groups of signals have the same timestamp and are transmitted to the receiving end synchronously.

[0095] The signal sampling unit samples the original signal transmitted by the signal capture unit at a periodic interval. The sampling function is recorded as s(t). The original analog signal is a continuous time signal, recorded as f(t), t∈R, then:

[0096] f s (t) = f(t)s(t)

[0097] Among them, f s (t) represents the time domain function after sampling, and Fourier transform is performed on it to convert the time domain function into the corresponding spectrum function:

[0098]

[0099] Among them, F s (t) represents the sampled spectral function, F(t) is the frequency domain expression of f(t), and S(t) is the frequency domain expression of s(t).

[0100] The sampling process converts a continuous signal into a discrete signal. The value of the discrete signal is the corresponding value of the original signal at the sampling time point. The sampled signal is discrete, but it can be further collected and processed at different timestamps (i.e., different time points). After sampling, the spectrum of the signal is periodically replicated, and the sampling frequency needs to be high enough to avoid aliasing and accurately restore the original signal.

[0101] If the original function is a Dirac shock signal, it is a very special signal. It is zero at almost all points in the time domain, except at t = 0, where its amplitude is infinite, but its integral is 1 over the entire time axis, expressed as:

[0102]

[0103] At this time, the discrete signal spectrum function after sampling is:

[0104]

[0105] The sampled discrete signal is a signal discretized at different time nodes. Each discrete point corresponds to a sampling time node, and the signal value at each time node is extracted from the Fourier transform of the original signal. In the discrete signal, there is a close connection between the sampling time node and the signal strength (such as spectrum information). Each discrete point corresponds to a sampling time node. Once the spectrum function of the sampled signal is obtained, a new analog signal is restored through the inverse Fourier transform, that is, it is converted back to the time domain to restore the waveform of the analog signal.

[0106] Further, the analog-to-digital conversion unit includes a signal grouping unit and an inverse analysis and restoration component;

[0107] The signal grouping unit is used to split the signal into three signal clusters with the same timestamp attribute;

[0108] The reverse parsing and recovery component is used to reversely recover the three groups of data that have been split and transmitted.

[0109] In the embodiment of the present invention, the signal is split into three signal clusters with the same timestamp attribute, specifically, the original analog signal is split into three signal clusters according to different time sequences but with the same timestamp attribute, that is, the three groups of split data will correspond to different parts or time periods of the original signal, and will be stored and transmitted separately through different time sequences. The splitting of these waveforms helps to reduce the influence of interference on the signal when restoring the signal at the receiving end, and provides higher timing accuracy.

[0110] The inverse analysis restoration component recombines the data collected at different time nodes and processes them through an inverse analysis algorithm so that they are completely aligned in time sequence, thereby restoring the original analog signal;

[0111] The inverse analysis algorithm formula is:

[0112] Among them, w(t) represents the reconstruction of different parts of the three groups of signals and the final inverse analysis to restore the original signal.

[0113] The operation of the signal grouping and inverse analysis and recovery components in the embodiment of the present invention is essentially to reduce the impact of interference, noise or distortion during the transmission of a single signal by dividing the original signal into multiple parts. Although the process of signal grouping and recovery cannot perfectly restore the original analog signal, it can effectively reduce the impact of interference by dividing the signal into multiple time sequences for transmission. Especially when facing problems such as multipath propagation, noise and signal attenuation, the signal inverse analysis algorithm and optimization strategy can minimize the error and restore a waveform close to the original signal. Therefore, the method of grouping and synchronous transmission is an effective solution to balance signal quality and anti-interference ability in the signal recovery process.

[0114] Further, the timestamp control unit includes a signal difference detection component, a signal merging component and a signal correction component;

[0115] The signal difference detection component is used to compare the received analog signal with the reverse-recovered analog signal, and identify the error generated in the recovery process by comparing the two;

[0116] The signal merging component is used to merge the directly received signal and the reversely recovered analog signal, and eliminate the error caused by the interference and recovery process by superimposing and merging the two, and finally obtain a waveform close to the original signal;

[0117] The signal correction component is used to further analyze and process the superimposed and combined signals to eliminate errors and deviations caused by interference with the received signals and deviations generated during the reverse recovery process.

[0118] Further, the signal merging component is used to merge the directly received signal and the reverse recovered analog signal, and eliminate the error caused by the interference and recovery process by superimposing and merging the two, specifically including:

[0119]

[0120] Among them, h t The function obtained by superimposing and merging the recovered continuous signal with the original signal forms a new combined signal. This process effectively offsets the error caused by interference during signal transmission and reduces the deviation generated in the recovery process, thereby achieving accurate signal recovery.

[0121] When the original impulse signal acquired is disturbed by error, it is expressed as:

[0122]

[0123] When the impact signal is recovered in reverse, due to the incompleteness of the recovery algorithm, the function will also introduce errors, which are manifested as:

[0124]

[0125] At this time, the new signal obtained by superimposing the restored signal and the error interference signal is expressed as:

[0126]

[0127] Through this superposition, the errors in the signal caused by interference or recovery process can offset each other, making the final signal closer to the original analog signal f(t).

[0128] In the embodiment of the present invention, the interference signal and the recovery error are offset by signal superposition and merging. If the errors of two signals in the system, such as the deviation directions of the interference signal and the recovery signal, are opposite, the two errors can be offset by superposition operation, so that the recovered signal is close to the original signal.

[0129] Embodiment 2 of the present invention provides an analog signal preprocessing method for suppressing excitation inrush current. The analog signal preprocessing system for suppressing excitation inrush current described in embodiment 1 is operated, comprising the following steps:

[0130] The external analog signal is acquired through the signal capture unit and collected by the signal sampling unit. The collection process is carried out at fixed time intervals.

[0131] The collected analog signal is converted into a digital signal through the analog-to-digital conversion unit and stored in the data storage unit;

[0132] After the data storage is completed, the digital signal reverse conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relationship between the timestamp and the signal strength based on the stored data;

[0133] The signal delay unit is used to delay the signal appropriately to ensure that the time point of analog signal recovery is consistent with the time required for signal acquisition and conversion. The timestamp control unit coordinates the work of each module to ensure the timing of the analog signal and the recovery signal is consistent;

[0134] The pre-processed and restored analog signal is outputted through the signal reconstruction output unit, and the A / D conversion signal module receives the pre-processed analog signal outputted by the signal reconstruction output unit and converts it into a digital signal;

[0135] The converted digital signal is transmitted to the logic judgment module, which monitors and analyzes the signal in real time. According to the set standard, if the signal shows abnormal excitation inrush current, an alarm is issued, and the control closing module controls the transformer to close according to the judgment result to suppress and eliminate the excitation inrush current.

[0136] The beneficial effect of the present invention is that, compared with the prior art,

[0137] 1) During the process of transformer closing and excitation inrush current control, the analog signal processing system effectively reduces the impact of external noise and interference on the signal through a variety of technical means, such as signal acquisition, filtering, timing synchronization, and signal recovery, ensuring accurate detection and control of excitation inrush current. This can not only improve the reliability of transformer commissioning, but also prevent malfunction of protection relays caused by misjudgment, thereby ensuring the safety of substation equipment and the stable operation of the power system;

[0138] 2) Collect the analog signal and ensure that the time interval of each collection is equal. This equal-interval collection method helps to ensure the consistency of signal data and provide a controllable data stream for subsequent processing. The signal delay unit is used to perform delay processing on the analog signal to ensure that the delay span is synchronized with the time of signal sampling and digital signal reverse conversion. The purpose of this delay processing is to ensure the synchronization of signal timing of different modules, thereby avoiding signal recovery errors or errors caused by inconsistent timing;

[0139] 3) The system splits the original analog signal into three groups of timing signals and transmits them separately, and then restores a signal close to the original waveform through reverse drawing technology at the receiving end. Although this method has certain errors, it greatly reduces the loss caused by signal interference and makes the recovered signal as close to the original signal as possible, thereby improving the robustness and recovery accuracy of the system.

[0140] Finally, 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An analog signal preprocessing system for suppressing excitation inrush current, characterized in that: include: Analog signal processing output module, A / D conversion signal module, logic judgment module and control closing module; The analog signal processing output module is used to perform signal modulation processing on the input analog signal and output the processed analog signal; The A / D conversion signal module is used to receive the processed analog signal and convert it into a digital signal; The logic judgment module is used to perform logic judgment and analysis on the converted digital signal, determine whether there is an abnormal excitation inrush current according to the set standard, and make corresponding response decisions; The control closing module is used to control the closing operation of the transformer to suppress the excitation inrush current according to the analysis result of the logic judgment unit.

2. The analog signal preprocessing system for suppressing excitation inrush current according to claim 1, characterized in that: The analog signal processing output module includes a signal capture unit, a signal sampling unit, an analog-to-digital conversion unit, a data storage unit, a digital signal reverse conversion unit, a signal delay unit, a timestamp control unit, and a signal reconstruction output unit; The signal capture unit is responsible for directly acquiring the original signal sent by the transformer bus transmitting end; The signal sampling unit is used to perform regular sampling of the original signal transmitted from the signal capturing unit through periodic time intervals; The analog-to-digital conversion unit is used to convert the signal strength obtained by each sampling into digital data, and match the digital data with the timestamp of the corresponding sampling; The data storage unit is used to store the collected signal data, including the timestamp information and signal strength data of each collection; The digital signal reverse conversion unit is used to reversely convert the digital signal into the original analog signal according to the timestamp stored in the data storage unit and the signal strength data corresponding to the timestamp; The signal delay unit is used to perform delay processing on the analog signal to ensure that the delay span is synchronized with the time of signal sampling and digital signal reverse conversion; The timestamp control unit is used to provide timestamp control for each unit to ensure that the timestamp of the received original signal is consistent with the timestamp of the original analog signal reversely converted by the digital signal reverse conversion unit; The signal reconstruction output unit is used to output the inverted and restored original analog signal.

3. The analog signal preprocessing system for suppressing excitation inrush current according to claim 2, characterized in that: The signal sampling unit includes a first timestamp data sampling component, a second timestamp data sampling component and a third timestamp data sampling component, each component is responsible for respectively collecting the signal strength of the analog signal and synchronously transmitting the collected data to the receiving end; The timestamp data sampling first component is used to obtain signal data of the analog signal at the (3n+1)T0 timestamp; The timestamp data sampling second component is used to obtain signal data of the analog signal at the (3n+2)T0 timestamp; The timestamp data sampling third component is used to obtain signal data of the analog signal at the (3n+3)T0 timestamp.

4. The analog signal preprocessing system for suppressing excitation inrush current according to claim 2, characterized in that: The analog-to-digital conversion unit includes a signal grouping unit and an inverse analysis and restoration component; The signal grouping unit is used to split the signal into three signal clusters with the same timestamp attribute; The reverse parsing and recovery component is used to perform reverse recovery on the three groups of data that have been split and transmitted.

5. The analog signal preprocessing system for suppressing excitation inrush current according to claim 2, characterized in that: The timestamp control unit includes a signal difference detection component, a signal merging component and a signal correction component; The signal difference detection component is used to compare the received analog signal with the reverse-recovered analog signal, and identify the error generated in the recovery process by comparing the two; The signal merging component is used to merge the directly received signal and the reversely recovered analog signal, and eliminate the errors caused by the interference and recovery process by superimposing and merging the two, and finally obtain a waveform curve that is highly overlapped with the waveform of the original signal; The signal correction component is used to further analyze and process the superimposed and combined signals to eliminate errors and deviations caused by interference with the received signals and deviations generated during the reverse recovery process.

6. A method for preprocessing analog signals for suppressing magnetizing inrush current, running on a system for preprocessing analog signals for suppressing magnetizing inrush current as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: The external analog signal is acquired through the signal capture unit and collected by the signal sampling unit. The collection process is carried out at fixed time intervals. The collected analog signal is converted into a digital signal through the analog-to-digital conversion unit and stored in the data storage unit; After the data storage is completed, the digital signal reverse conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relationship between the timestamp and the signal strength based on the stored data; The signal delay unit is used to delay the signal appropriately to ensure that the time point of analog signal recovery is consistent with the time required for signal acquisition and conversion. The timestamp control unit coordinates the work of each module to ensure the timing of the analog signal and the recovery signal is consistent; The pre-processed and restored analog signal is outputted through the signal reconstruction output unit, and the A / D conversion signal module receives the pre-processed analog signal outputted by the signal reconstruction output unit and converts it into a digital signal; The converted digital signal is transmitted to the logic judgment module, which monitors and analyzes the signal in real time. According to the set standard, if the signal shows abnormal excitation inrush current, an alarm is issued, and the control closing module controls the transformer to close according to the judgment result to suppress and eliminate the excitation inrush current.

7. The analog signal preprocessing method for suppressing excitation inrush current according to claim 6, characterized in that: In the method, the signal sampling unit is used for acquisition specifically as follows: The signal sampling unit samples the original signal transmitted by the signal capture unit at a periodic interval. The sampling function is recorded as s(t). The original analog signal is a continuous-time signal, recorded as f(t). Then: f s (t)=f(t)s(t) Among them, f s (t) represents the time domain function after sampling, and Fourier transform is performed on it to convert the time domain function into the corresponding spectrum function: Among them, F s (t) represents the sampled spectral function, F(t) is the frequency domain expression of f(t), and S(t) is the frequency domain expression of s(t).

8. The analog signal preprocessing system for suppressing excitation inrush current according to claim 6 or 7, characterized in that: The digital signal reverse conversion unit reversely converts the digital signal into an analog signal waveform according to the corresponding relationship between the timestamp and the signal strength according to the stored data, specifically: The data collected at different time nodes are recombined and processed through the inverse analysis algorithm so that they are completely aligned in time sequence, thereby restoring the original analog signal; The inverse analysis algorithm formula is: Among them, w(t) represents the spectrum function F after sampling s (t) is a continuous function formed after inverse analysis.

9. The analog signal preprocessing method for suppressing excitation inrush current according to claim 8, characterized in that: The method also includes combining the directly received original signal and the reversely recovered analog signal, and eliminating errors caused by interference and recovery processes by superimposing and combining the two, specifically: Among them, h t It represents the function obtained by superimposing and merging the restored continuous signal with the original signal to form a new combined signal.

10. The analog signal preprocessing method for suppressing excitation inrush current according to claim 9, characterized in that: The errors include: When the original impulse signal acquired is disturbed by errors, it is expressed as: When the impact signal is reversely recovered, the function error is expressed as: At this time, the new signal obtained by superimposing the restored signal and the error interference signal is expressed as: Through this superposition, the errors in the signal caused by interference and recovery process cancel each other out, making the final signal more consistent with the original analog signal h(t) waveform.

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