A detection method for electrical automation power supply system

Abstract

The present invention discloses a detection method for an electrical automation power supply system, which relates to the field of power supply detection technology and solves the problem that it is not possible to accurately identify whether a corresponding line is affected by harmonics and synchronously suppress the harmonics based on the detected harmonics. The present invention is aimed at relevant lines affected by harmonics, and preferentially locks the third harmonic related to it based on the fundamental waveform associated in each phase circuit, and then selects the mean value related to it based on the amplitude of several third harmonics, so as to determine the corresponding waveform based on several groups of mean values, and then compares the determined waveform with the historical waveform, selects the closest regular waveform, and subsequently regenerates the suppression wave of such regular waveform, and performs harmonic suppression on the lines affected by harmonics, so as to achieve better power supply transmission effect and improve power supply safety.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply detection, and in particular to a detection method for an electrical automation power supply system. Background Art

[0002] An automated power supply system is an electric power system that uses modern control technology, computer technology, and communication technology to automatically monitor, control, protect, and manage the power supply process. It can improve the reliability, safety, and efficiency of power supply, adapt to the needs of different loads, and quickly respond to and handle faults and abnormal conditions in the system.

[0003] The application with publication number CN118606874A discloses a detection method for an electrical automation power supply system, which includes: obtaining current data of each carbon brush in the generator of the electrical automation power supply system at each collection moment; obtaining each current subsequence of each carbon brush; determining the carbon brush current trend fluctuation amount of each current subsequence based on the change trend and random fluctuation degree of the current data in each current subsequence; determining the current peak abnormality coefficient of each current subsequence based on the abnormality degree of the peak in each current subsequence and the carbon brush current trend fluctuation amount; determining the current balancing coefficient between any two carbon brushes based on the similarity between the current data of any two carbon brushes and the corresponding current peak abnormality coefficients; and further judging the fault condition of the carbon brush in the generator.

[0004] During the power supply process, the electrical automation power supply system generally uses corresponding monitoring sensors to monitor whether the corresponding line is in a normal line transportation state. However, the original detection method only monitors relatively obvious abnormal conditions, but cannot accurately identify whether the corresponding line is affected by harmonics. Synchronous suppression is performed based on the detected harmonics to ensure the normal operation of the power supply system. Summary of the Invention

[0005] In response to the deficiencies of the prior art, the present invention provides an electrical automation power supply system detection method, which solves the problem that it is not possible to accurately identify whether the corresponding line is affected by harmonics and does not synchronously suppress the detected harmonics.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for detecting an electrical automation power supply system, comprising the following steps:

[0007] Step 1: Monitor the neutral current of each branch line of the power supply system, and based on the specific current parameters monitored, identify whether the corresponding branch line is a normal line, a fault line, or a line to be analyzed. The specific sub-steps are:

[0008] Monitor the neutral current of each branch line and mark it as D i , where i represents different branch lines, if D i ≤Y1, it means that this branch line is a normal line and no processing is required;

[0009] If D i > Y1, then the associated timing is performed based on the current moment. If the zero line current of this branch line is always at D i >Y1 state, and its subsequent period is the preset period, then this branch line is directly marked as a pending line, otherwise, it continues to monitor;

[0010] Identify whether the three-phase currents in the pending line are equal at the current moment. If they are equal, it means that the pending line is in a three-phase balanced state, but there is current in the neutral line, so a line fault signal is directly generated for display, and the pending line is marked as a fault line. If they are not equal, it means that the pending line is in a three-phase unbalanced state, so the pending line is directly marked as the line to be analyzed;

[0011] Step 2: Based on the determined line to be analyzed, the three-phase current and neutral current associated with the line are synchronously confirmed. Based on the specific values ​​of the confirmed neutral current and three-phase current, it is assessed whether there is harmonic influence in the line to be analyzed and marked as a harmonic influence line. The specific method is as follows:

[0012] S21. Calibrate the three-phase currents confirmed at the current moment as Da, Db, and Dc, respectively, and calibrate the confirmed neutral current as Do;

[0013] S22. Identify whether Do, Da, Db, and Dc satisfy the following conditions: If the conditions are met, it means that the line to be analyzed is not affected by harmonics, and a three-phase load imbalance signal is generated for display. If the conditions are not met, it means that the line to be analyzed is affected by harmonics, and the line to be analyzed is marked as a harmonic-affected line.

[0014] Step 3: Based on the confirmed harmonic-affected circuit, first confirm the fundamental frequency of each phase in the three-phase circuit in the harmonic-affected circuit, and then, based on the harmonic waveforms generated by each phase collected by the harmonic analyzer, confirm the third harmonic associated with the corresponding fundamental frequency based on the confirmed fundamental frequency. The specific sub-steps are as follows:

[0015] S31. Determine the fundamental frequency of each phase from the three-phase circuit in the harmonic-affected line and mark it as P i , where i represents one of the three phases;

[0016] S32. Several groups of harmonic waveforms collected from the single-phase circuit of the harmonic-affected line:

[0017] Single group harmonic waveform processing: Confirm each peak point in the harmonic waveform in turn. The waveform segments before and after the peak point have opposite trends. The waveform segment before the peak point is in a climbing state, while the waveform segment after the peak point is in a descending state. The time interval between adjacent peak points is calibrated as t k , where k represents the waveform segment between different peak points, using F=1÷t k Confirm the frequency value F of this waveform segment, perform average processing on the frequency values ​​F of several waveform segments confirmed by this harmonic waveform, and use the average value obtained by processing as the harmonic frequency X of this harmonic waveform. i-q , where i represents one of the three phases, and q represents different harmonic waveforms;

[0018] S33, based on the harmonic frequency X confirmed by several groups of harmonic waveforms i-q , and based on the fundamental frequency P associated with this phase i Lock search value: (3×P i ), from several harmonic frequencies X i-q Select (3×P i ) The harmonic waveform associated with the harmonic frequency is calibrated as the third harmonic associated with the fundamental wave of this phase;

[0019] S34, repeating steps S31-S33 until the third harmonic associated with each phase fundamental wave in the harmonic-affected line is determined;

[0020] Step 4: Based on the third harmonic associated with each phase confirmed by this harmonic-affecting line, the three groups of third harmonics are combined, and when combined, the relevant zero points are made to coincide. Then, based on the power size of the corresponding third harmonic waveform, a set of common frequency waveforms is generated. The specific sub-steps are:

[0021] S41. Combining the three sets of third harmonic waveforms so that a zero point within the three sets of waveforms overlaps, and the waveform segments following the corresponding zero point are in a climbing state. After the three sets of zero points overlap, the normal waveform state of the three sets of waveforms remains unchanged.

[0022] S42. Marking points on the same vertical line within the three groups of waveforms as common frequency points, based on the common frequency points, confirming the amplitudes associated with the common frequency points, selecting the averages associated with the three groups of amplitudes based on the different amplitudes associated with the three groups of common frequency points, determining the average point, and confirming each of the subsequent associated average points one by one;

[0023] S43, sequentially connecting the multiple confirmed mean value points to determine a set of common frequency waveforms;

[0024] Step 5: Based on the confirmed common frequency waveform, identify the associated waveform closest to the common frequency waveform from the historical completed data, and based on the power magnitude and power direction of the associated waveform, generate a suppression wave with the same power magnitude but opposite power direction through the active power filter to suppress the harmonics generated in the harmonic-affected line. The specific sub-steps are as follows:

[0025] S51. Combining the initial zero point of the associated historical waveform with the initial zero point of the power frequency waveform from the historical completion data, and after the combination is completed, identifying the area of ​​the region generated by the intersection of the waveform segments of the historical waveform and the power frequency waveform, and summing the areas of the regions to obtain a close characteristic value belonging to the corresponding historical waveform;

[0026] S52, selecting a historical waveform associated with a minimum value from a plurality of approximate characteristic values ​​confirmed by the plurality of historical waveforms, and marking the historical waveform as an associated waveform of the common frequency waveform;

[0027] S53. Then, an active power filter is used to generate a suppression wave with the same power magnitude but opposite power direction to the associated waveform, and the suppression wave is used to suppress the harmonics generated in the harmonic-affected line.

[0028] The present invention provides a method for detecting an electrical automation power supply system. Compared with the prior art, it has the following advantages:

[0029] The present invention monitors the current characteristics of the power supply line and directly determines anomalies by identifying whether there is current in the neutral line. It then re-analyzes the line with the anomaly and determines whether the three-phase current in the line is balanced to assess whether the corresponding line is affected by the corresponding harmonics. This sequential inspection method can gradually identify related problems and ensure accuracy.

[0030] For relevant lines affected by harmonics, the third harmonic related to it is locked based on the fundamental waveform associated with each phase circuit. Then, based on the amplitudes of several third harmonics, the related mean is selected, and the corresponding waveform is determined based on several groups of mean values. Then, the determined waveform is compared with the historical waveform, and the closest regular waveform is selected. Subsequently, a suppression wave of this regular waveform is generated to suppress harmonics on the lines affected by harmonics, so as to achieve better power supply transmission effect and improve power supply safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the process of the present invention;

[0032] Figure 2 Schematic diagram of waveform processing of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] See also Figure 1 , the present application provides a method for detecting an electrical automation power supply system, comprising the following steps:

[0035] Step 1: Monitor the neutral current of each branch line of the power supply system, and based on the specific current parameters monitored, identify whether the corresponding branch line is a normal line, a fault line, or a line to be analyzed. Specifically, if the branch line is in a normal current transmission state and there is no relevant influence of three-phase load or harmonics, then the optimal value of its neutral current is 0, but some fluctuation is allowed. Because there may be some fluctuation in the three-phase circuit, which generates a neutral current, it is necessary to refer to the associated preset value Y1 when making a judgment. Y1 is formulated by relevant operators based on experience. The specific sub-steps for calibrating the branch line are:

[0036] S11. Monitor the neutral current of each branch line and mark it as D i , where i represents different branch lines, if D i ≤Y1, it means that this branch line is a normal line and no processing is required;

[0037] If D i > Y1, then the associated timing is performed based on the current moment. If the zero line current of this branch line is always at D i >Y1 state, the subsequent period is the preset period, generally 2 minutes or even shorter, then this branch line is directly marked as a pending line, otherwise, it will continue to monitor;

[0038] Identify whether the three-phase currents in the pending line are equal at the current moment. If they are equal, it means that the pending line is in a three-phase balanced state, but there is current in the neutral line. Therefore, a line fault signal is directly generated for display, and the pending line is marked as a fault line (indicating that there is a fault in this line. Under normal circumstances, the three-phase currents are in a balanced state, and the current of the neutral line is generally 0, and there is no value). If they are not equal, it means that the pending line is in a three-phase unbalanced state, so the pending line is directly marked as the line to be analyzed;

[0039] Specifically, once the line to be analyzed is determined, it means that there is an abnormality in the power transmission of this branch line, which causes current to be generated in the neutral line. Therefore, it is necessary to conduct a specific analysis of this line to be analyzed to determine the reason why the current in the neutral line is generated in this line to be analyzed.

[0040] The three-phase balanced state is: in a three-phase AC system, the three phases are A, B and C. These three phases are generated by a three-phase AC generator. The generator has three sets of stator windings, which are 120° apart in spatial position. The current distribution systems all use three-phase AC. When the rotor of the generator rotates, electromagnetic induction generates an induced electromotive force in the three sets of stator windings, thereby forming a three-phase current. The three-phase balanced state is: the current values ​​associated with phases A, B and C are equal, so it is a three-phase balanced state. The three-phase unbalanced state is that the current values ​​associated with the three phases are unequal.

[0041] Step 2: Based on the determined line to be analyzed, the three-phase current and neutral current associated with the line are synchronously confirmed. Based on the specific values ​​of the confirmed neutral current and three-phase current, the line to be analyzed is evaluated for harmonic influence and marked as a harmonic influence line. Specifically, when there is no harmonic influence, the neutral current and the three-phase current have a normal numerical equation relationship. However, when there is harmonic influence (basically the third harmonic influence, because the third harmonic has the same direction, the current will be superimposed on the neutral line, resulting in the neutral line current being greater than the maximum value of the three-phase current, which may cause the neutral line to burn out in severe cases), the specific method for evaluating whether there is harmonic influence in the line to be analyzed is as follows:

[0042] S21. Calibrate the three-phase currents confirmed at the current moment as Da, Db, and Dc, respectively, and calibrate the confirmed neutral current as Do;

[0043] S22. Identify whether Do, Da, Db, and Dc satisfy the following conditions: If the conditions are met, it means that the line to be analyzed is not affected by harmonics, and a three-phase load imbalance signal is generated for display. Based on this three-phase load imbalance signal, external personnel adjust the relevant electrical equipment in the line to be analyzed, such as the inverter and power supply. If the conditions are not met, it means that the line to be analyzed is affected by harmonics, and the line to be analyzed is marked as a harmonic influence line. If the corresponding standard is not met, it means that the corresponding harmonic current exists in the corresponding neutral line, resulting in a numerical imbalance. Therefore, the existence of harmonic influence can be confirmed.

[0044] Step 3: Based on the confirmed harmonic-affected circuit, first confirm the fundamental frequency of each phase in the three-phase circuit in the harmonic-affected circuit, and then confirm the third harmonic associated with the corresponding fundamental wave based on the harmonic waveform generated by each phase collected by the harmonic analyzer and the confirmed fundamental wave frequency. Specifically, the third harmonic has the same direction and is the main harmonic that causes current superposition on the neutral line, so the corresponding third harmonic can be directly determined. The specific sub-steps for confirming the third harmonic associated with the corresponding fundamental wave are:

[0045] S31. Determine the fundamental frequency of each phase from the three-phase circuit in the harmonic-affected line and mark it as P i , where i represents one of the three phases. Under normal circumstances, the fundamental frequency of each phase is equal and is 50Hz. The fundamental wave is the normal circuit waveform;

[0046] S32. Several groups of harmonic waveforms collected from the single-phase circuit of the harmonic-affected line:

[0047] Single group harmonic waveform processing: Confirm each peak point in the harmonic waveform in turn. The waveform segments before and after the peak point have opposite trends. The waveform segment before the peak point is in a climbing state, while the waveform segment after the peak point is in a descending state. The time interval between adjacent peak points is calibrated as t k , where k represents the waveform segment between different peak points, using F=1÷t k Confirm the frequency value F of this waveform segment, perform average processing on the frequency values ​​F of several waveform segments confirmed by this harmonic waveform (the number of which is not less than thirty groups), and use the average value obtained by processing as the harmonic frequency X of this harmonic waveform i-q , where i represents one of the three phases, and q represents different harmonic waveforms;

[0048] S33, based on the harmonic frequency X confirmed by several groups of harmonic waveforms i-q , and based on the fundamental frequency P associated with this phase i Lock search value: (3×P i ), from several harmonic frequencies X i-q Select (3×P i ) The harmonic waveform associated with this harmonic frequency is calibrated as the third harmonic associated with this phase fundamental wave. The frequency of the third harmonic is three times the fundamental frequency. Therefore, the search value is determined from the confirmed fundamental frequency to lock the closest associated value. The closest meaning is that the two values ​​are closest. For example, if the fundamental frequency is 50Hz, and its harmonic frequencies are 99.9Hz and 149.8Hz respectively, then it can be seen that the harmonic waveform associated with 149.8Hz is the third harmonic of this fundamental wave.

[0049] S34, repeating steps S31-S33 until the third harmonic associated with each phase fundamental wave in the harmonic-affected line is determined;

[0050] Step 4: Based on the third harmonic associated with each phase confirmed by the harmonic-affecting line, the three groups of third harmonics are combined, and when combined, the relevant zero points are made to coincide. Then, based on the power magnitude of the corresponding third harmonic waveform, a set of common frequency waveforms is generated. Specifically, the power waveform has peak points and valley points, which change from top to bottom. When the change intersects with the corresponding horizontal coordinate axis, the corresponding intersection point is the zero point;

[0051] The specific sub-steps for generating the common frequency waveform are:

[0052] S41. Combining the three sets of third harmonic waveforms so that a zero point within the three sets of waveforms overlaps, and the waveform segment following the corresponding zero point must be in a rising state (if one waveform is in a rising state and the other waveform is in a falling state, the generated common frequency waveforms will be significantly different and the deviation will also be large, which will cause errors in subsequent suppression processing). After the three sets of zero points overlap, the normal waveform state of the three sets of waveforms remains unchanged;

[0053] S42. Mark the points on the same vertical line in the three groups of waveforms as common frequency points. Based on the common frequency points, confirm the amplitude associated with the common frequency points (that is, the value on the vertical coordinate axis. If it is a voltage fundamental waveform, the unit of its amplitude is volt; if it is a current fundamental waveform, the unit of its amplitude is ampere). Based on the different amplitudes associated with the three groups of common frequency points, select the average of the three groups of amplitudes and determine the average point. Then confirm the subsequent associated several average points one by one, and combine Figure 2 After the three confirmed waveforms are combined at the corresponding zero point, the subsequent waveform segments are all in a unified climbing state. There are three common frequency points G1, G2, and G3 on the same vertical line. Based on the corresponding amplitudes associated with the three points, the corresponding mean point can be locked. The common frequency point on each vertical line can be determined in turn, and then each mean point can also be determined, so that the corresponding common frequency waveform can be locked;

[0054] S43. Connect the multiple confirmed mean value points in sequence to determine a set of common frequency waveforms (the confirmed common frequency waveforms at this time may not be completely regular waveforms, and may be irregular waveform segments or curve segments, etc.).

[0055] Step 5: Based on the confirmed common frequency waveform, identify the associated waveform closest to the common frequency waveform from the historical completed data, and based on the power magnitude and power direction of the associated waveform, generate a suppression wave with the same power magnitude but opposite power direction through the active power filter to suppress the harmonics generated in the harmonic-affected line. The specific sub-steps of identifying the associated waveform are:

[0056] S51. Combining the initial zero point of the associated historical waveform with the initial zero point of the power frequency waveform from the historical completion data, and after the combination is completed, identifying the area of ​​the region generated by the intersection of the waveform segments of the historical waveform and the power frequency waveform, and summing the areas of several regions to obtain a close characteristic value belonging to the corresponding historical waveform. Specifically, during the normal waveform change process, two waveform segments will have intersection points, and two adjacent intersection points will have corresponding intersection areas, and the intersection areas will have corresponding area values, so that the total area of ​​the region can be determined. When the total area of ​​the region is the minimum, it means that the corresponding waveform is closest to the current waveform, so that waveform selection can be performed, and when waveform suppression is performed later, better suppression effect can be achieved;

[0057] S52, selecting a historical waveform associated with a minimum value from a plurality of approximate characteristic values ​​confirmed by the plurality of historical waveforms, and marking the historical waveform as an associated waveform of the common frequency waveform;

[0058] S53. Then, an active power filter is used to generate a suppression wave with the same power magnitude but opposite power direction to the associated waveform, and the suppression wave is used to suppress the harmonics generated in the harmonic-affected line.

[0059] Active power filter, the active power filter detects the harmonic components in the load current, then generates a compensation current equal to the harmonic current in magnitude and opposite in direction, and injects it into the grid, thereby offsetting the harmonic current generated by the load and making the grid current close to a sine wave; it is mainly based on the instantaneous reactive power theory and uses control algorithms to achieve rapid detection and compensation of harmonics and reactive power.

[0060] Some of the data in the above formulas are dimensionless and numerically calculated. Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0061] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. 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 method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A method for detecting an electrical automation power supply system, characterized in that: The following steps are involved: Step 1: Monitor the neutral current of each branch line of the power supply system, and identify whether the corresponding branch line is a normal line, a fault line, or a line to be analyzed based on the specific current parameters monitored; Step 2: Based on the determined line to be analyzed, the three-phase current and neutral current associated with the line are synchronously confirmed. Based on the specific values ​​of the confirmed neutral current and three-phase current, it is assessed whether there is harmonic influence in the line to be analyzed and marked as a harmonic influence line; Step 3: Based on the confirmed harmonic-affecting circuit, first determine the fundamental frequency of each phase in the three-phase circuit of the harmonic-affecting circuit, and then, based on the harmonic waveforms generated by each phase collected by the harmonic analyzer, determine the third harmonic associated with the corresponding fundamental frequency based on the confirmed fundamental frequency; Step 4: Based on the third harmonic associated with each phase identified by the harmonic-affecting line, the three groups of third harmonics are combined, and when combined, the relevant zero points are made to coincide. Then, based on the power magnitude of the corresponding third harmonic waveform, a set of common frequency waveforms is generated; Step 5: Based on the confirmed common frequency waveform, the associated waveform closest to the common frequency waveform is identified from the historical completed data. Based on the power magnitude and power direction of the associated waveform, a suppression wave with the same power magnitude but opposite power direction is generated by the active power filter to suppress the harmonics generated in the harmonic-affected line. In step 2, the specific method for evaluating whether there is harmonic influence in the line to be analyzed is: S21. Calibrate the three-phase currents confirmed at the current moment as Da, Db, and Dc, respectively, and calibrate the confirmed neutral line current as Do; S22. Identify whether Do, Da, Db, and Dc satisfy the following conditions: If it is satisfied, it means that the line to be analyzed is not affected by harmonics, and a three-phase load imbalance signal is generated for display. If it is not satisfied, it means that the line to be analyzed is affected by harmonics, and the line to be analyzed is marked as a harmonic-affected line.

2. The electrical automation power supply system detection method according to claim 1, characterized in that: In step 1, the specific sub-steps for identifying which line the branch line belongs to are: Monitor the neutral current of each branch line and mark it as D i , where i represents different branch lines, if D i ≤Y1, it means that this branch line is a normal line and no processing is required; If D i > Y1, then the associated timing is performed based on the current moment. If the zero line current of this branch line is always at D i >Y1 state, and its subsequent period is the preset period, then this branch line is directly marked as a pending line, otherwise, it continues to monitor; Identify whether the three-phase currents in the pending line are equal at the current moment. If they are equal, it means that the pending line is in a three-phase balanced state, but there is current in the neutral line, so the line fault signal is directly generated for display, and the pending line is marked as a fault line. If they are not equal, it means that the pending line is in a three-phase unbalanced state, so the pending line is directly marked as the line to be analyzed.

3. The electrical automation power supply system detection method according to claim 1, characterized in that: In step 3, the specific sub-steps for confirming the third harmonic associated with the corresponding fundamental wave are: S31. Determine the fundamental frequency of each phase from the three-phase circuit in the harmonic-affected line and mark it as P i , where i represents one of the three phases; S32. Several groups of harmonic waveforms collected from the single-phase circuit of the harmonic-affected line: Single group harmonic waveform processing: Confirm each peak point in the harmonic waveform in turn. The waveform segments before and after the peak point have opposite trends. The waveform segment before the peak point is in a climbing state, while the waveform segment after the peak point is in a descending state. The time interval between adjacent peak points is calibrated as t k , where k represents the waveform segment between different peak points, using F=1÷t k Confirm the frequency value F of this waveform segment, perform average processing on the frequency values ​​F of several waveform segments confirmed by this harmonic waveform, and use the average value obtained by processing as the harmonic frequency X of this harmonic waveform. i-q , where i represents one of the three phases, and q represents different harmonic waveforms; S33, based on the harmonic frequency X confirmed by several groups of harmonic waveforms i-q , and based on the fundamental frequency P associated with this phase i Lock search value: (3×P i ), from several harmonic frequencies X i-q Select (3×P i ) The harmonic waveform associated with the harmonic frequency is calibrated as the third harmonic associated with the fundamental wave of this phase; S34. Repeat steps S31-S33 until the third harmonics associated with the fundamental wave of each phase in the harmonic-affected line are determined.

4. The electrical automation power supply system detection method according to claim 1, characterized in that: In step 4, the specific sub-steps of generating the common frequency waveform are: S41. Combining the three sets of third harmonic waveforms so that a zero point within the three sets of waveforms overlaps, and the waveform segments following the corresponding zero point are in a climbing state. After the three sets of zero points overlap, the normal waveform state of the three sets of waveforms remains unchanged. S42. Marking points on the same vertical line within the three groups of waveforms as common frequency points, based on the common frequency points, confirming the amplitudes associated with the common frequency points, selecting the averages associated with the three groups of amplitudes based on the different amplitudes associated with the three groups of common frequency points, determining the average point, and confirming each of the subsequent associated average points one by one; S43. Connect the multiple mean value points that have been confirmed one by one in sequence to determine a set of common frequency waveforms.

5. The electrical automation power supply system detection method according to claim 1, characterized in that: In step 5, the specific sub-steps of identifying the associated waveforms are: S51. Combining the initial zero point of the associated historical waveform with the initial zero point of the power frequency waveform from the historical completion data, and after the combination is completed, identifying the area of ​​the region generated by the intersection of the waveform segments of the historical waveform and the power frequency waveform, and summing the areas of the regions to obtain a close characteristic value belonging to the corresponding historical waveform; S52, selecting a historical waveform associated with a minimum value from a plurality of approximate characteristic values ​​confirmed by the plurality of historical waveforms, and marking the historical waveform as an associated waveform of the common frequency waveform; S53. Then, an active power filter is used to generate a suppression wave with the same power magnitude but opposite power direction to the associated waveform, and the suppression wave is used to suppress the harmonics generated in the harmonic-affected line.

Images