Electronic leakage intelligent monitoring method for high-power power distribution unit

Abstract

The application provides an electronic leakage intelligent monitoring method for a high-power power distribution unit, and belongs to the technical field of control, which comprises the following steps: collecting data for the high-power power distribution unit; processing the transmitted current by a metering chip of the high-power power distribution unit; calculating the zero-sequence current according to an improved algorithm by a processing module of the metering chip after filtering the current; and identifying three-phase unbalanced leakage and ground line leakage according to the zero-sequence current by the processing module of the metering chip. Thus, the leakage detection is triggered by the zero-sequence current safety threshold value, the fundamental wave phase deviation type three-phase unbalanced leakage is identified by combining the three-phase phase deviation threshold value, the harmonic interference type three-phase unbalanced leakage is identified by the three-phase total harmonic distortion rate average value threshold value, and the ground line leakage is identified by comprehensive judgment, so that the leakage type of the high-power power distribution unit is accurately distinguished.

Description

Technical Field

[0001] The present invention belongs to the field of control technology, and in particular relates to an intelligent electronic leakage monitoring method for a high-power power distribution unit. Background Art

[0002] High-power power distribution units (PDUs) are professional power distribution devices designed for cabinet-mounted electrical equipment. Compared to household sockets, their core advantages lie in high load capacity, professional safety protection, and adaptability to industrial environments.

[0003] High-power power distribution units are generally three-phase output smart PDUs, just like the three-phase output smart PDU mentioned in the Chinese patent with patent publication number "CN219163837U" and application date of February 13, 2023. The three-phase output smart PDU is usually integrated with an input unit, an output unit and a control unit, wherein the execution module of the control unit includes components such as contactors and metering chips, which are used to realize leakage monitoring, line control and metering functions of the three-phase transmission circuit.

[0004] Specifically, high-power power distribution units typically rely on single-phase detection for each line of each three-phase output socket to implement leakage protection. However, this approach has obvious drawbacks: single-phase detection alone cannot accurately identify leakage caused by three-phase imbalance in the high-power power distribution unit or ground wire leakage. When the three-phase current imbalance exceeds the safety threshold or a ground wire leaks, single-phase detection is difficult to accurately determine, which may lead to delayed leakage protection or misjudgment, posing potential risks to equipment and personnel safety.

[0005] Therefore, a more comprehensive and accurate leakage monitoring method is needed to solve the problem in the prior art that three-phase imbalance or ground wire leakage of a high-power power distribution unit cannot be accurately identified. Summary of the Invention

[0006] The purpose of the present invention is to provide an intelligent electronic leakage monitoring method for a high-power power distribution unit, so as to realize comprehensive monitoring of the three-phase line leakage of the high-power power distribution unit, accurately identify the three-phase unbalanced leakage and ground wire leakage of the high-power power distribution unit, and improve the safety of the high-power power distribution unit.

[0007] The present invention utilizes the following technical solutions.

[0008] An intelligent monitoring method for electronic leakage of a high-power power distribution unit, comprising:

[0009] Step 1: Collect data from the high-power power distribution unit;

[0010] Step 2: The metering chip of the high-power power distribution unit processes the A-phase current, B-phase current, C-phase current, and ground wire current transmitted from the three-phase output socket;

[0011] Step 3: The processing module of the metering chip calculates the zero-sequence current based on the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket after filtering according to the improved algorithm;

[0012] Step 4: The processing module of the metering chip identifies three-phase unbalanced leakage and ground wire leakage based on the zero-sequence current.

[0013] Furthermore, step 1 specifically includes:

[0014] Step 1-1: Construct an intelligent electronic leakage monitoring device for a high-power power distribution unit, namely, connect the three contactors and four current sensors of the high-power power distribution unit to the metering chip, respectively connect the three contactors to three transmission lines, and connect three of the four current sensors to the three transmission lines. The three transmission lines are respectively connected to three phases of the three-phase output socket of the high-power power distribution unit, and the remaining current sensor of the four current sensors is connected to the ground wire of the three-phase output socket of the high-power power distribution unit.

[0015] Step 1-2: The four current sensors respectively and synchronously collect the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket in real time, and transmit the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket to the metering chip.

[0016] Furthermore, step 2 specifically includes:

[0017] The metering chip of the high-power power distribution unit filters the transmitted A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, that is, it uses a mean filtering algorithm to remove high-frequency interference signals in the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, and transmits the filtered A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket to the processing module of the metering chip.

[0018] Furthermore, step 3 specifically includes:

[0019] The following zero-sequence current calculation formula with an improved algorithm is implemented:

[0020] ;

[0021] in Indicates the zero-sequence current calculated according to the improved algorithm; 、 and They represent the effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket respectively. The effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket are the effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket respectively after filtering; 、 and They respectively represent the fundamental wave phase angle of the A-phase current, the fundamental wave phase angle of the B-phase current, and the fundamental wave phase angle of the C-phase current of the three-phase output socket after filtering; 、 and Respectively represent the total harmonic current RMS value of phase A, phase B, and phase C of the three-phase output socket; Indicates the effective value of the ground wire current of the three-phase output socket. That is, the ground wire current after filtering; Indicates the fundamental current correction coefficient; Indicates the harmonic current correction factor; Indicates the ground wire coupling coefficient.

[0022] Furthermore, in step 3, 、 and The calculation formula is:

[0023] ;

[0024] in Indicates the amplitude of the sinusoidal component of the A-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the A-phase current of the three-phase output socket after filtering; Indicates the amplitude of the sinusoidal component of the B-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the B-phase current of the three-phase output socket after filtering; Indicates the amplitude of the sinusoidal component of the C-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the C-phase current of the three-phase output socket after filtering; It represents the fundamental angular frequency of three-phase alternating current. The calculation formula is ,in is the grid frequency, Indicates the start time of collecting the A-phase current, B-phase current, or C-phase current of the three-phase output socket.

[0025] Furthermore, in step 3, The calculation formula is:

[0026] ;

[0027] in represents the dimensionless denominator, 0 represents the target phase mean, and the constant 0.005 represents the correction coefficient of the phase deviation on the fundamental zero-sequence component; when the calculation result When it is less than 0.8, Take 0.8; When it is greater than 1.2, Take 1.2.

[0028] Furthermore, in step 3, The calculation formula is:

[0029] ;

[0030] in 、 and Respectively represent the total harmonic distortion rate of phase A, phase B and phase C of the three-phase output socket. The total harmonic distortion rate of phase A, phase B and phase C of the three-phase output socket can be obtained by the method of the existing technology; 0.3 represents the basic offset of the harmonic current correction coefficient; 0.2 represents the proportional coefficient; 3×50% represents the preset three-phase total harmonic distortion reference value; when the calculation result When it is less than 0.3, Take 0.3; When it is greater than 0.5, Take 0.5.

[0031] Furthermore, in step 3, The calculation formula is:

[0032] ;

[0033] in , 0.6 represents the ground wire coupling coefficient The lower limit value, 0.3 represents an adjustment coefficient, when the calculation result When it is less than 0.6, Take 0.6; When it is greater than 0.9, Take 0.9.

[0034] Furthermore, step 4 specifically includes:

[0035] Step 4-1: The processing module of the metering chip processes the zero-sequence current according to the preset threshold value. Conduct leakage identification;

[0036] Step 4-1 specifically includes:

[0037] like , it is determined that there is no significant leakage risk in the transmission line;

[0038] like , it is determined that there is a leakage risk in the transmission line, triggering the subsequent leakage type identification process and the metering chip controls the three contactors to disconnect;

[0039] The subsequent leakage type identification process is triggered as follows:

[0040] Step 4-2: According to the preset threshold Identify three-phase unbalanced leakage with fundamental wave phase deviation;

[0041] Step 4-3: According to the preset threshold Identify three-phase unbalanced leakage caused by harmonic interference;

[0042] Step 4-4: Comprehensively judge and identify ground wire leakage.

[0043] Furthermore, step 4-2 specifically includes:

[0044] Calculate the deviation between the actual phase difference of the three phases and the ideal phase difference 、 and :

[0045] ;

[0046] If exists 、 or , and the fundamental component in the zero-sequence current accounts for , it is determined that there is a fundamental wave phase deviation type three-phase unbalanced leakage in the transmission line, and the information of the fundamental wave phase deviation type three-phase unbalanced leakage is transmitted to a display screen connected to the metering chip through the metering chip for display.

[0047] Furthermore, step 4-3 specifically includes:

[0048] Calculate the average value of three-phase total harmonic distortion :

[0049] ;

[0050] like , and the proportion of harmonic components in zero-sequence current , it is determined that there is harmonic interference type three-phase unbalanced leakage in the transmission line, and the information of the harmonic interference type three-phase unbalanced leakage is transmitted to the display screen connected to the metering chip through the metering chip for display.

[0051] Furthermore, step 4-4 specifically includes:

[0052] when When the following three conditions are met:

[0053] Condition 1: Effective value of the ground wire current of the three-phase output socket ;

[0054] Condition 2: The proportion of ground wire coupling items is ≥50%;

[0055] Condition three: 、 and ;

[0056] It is determined that there is ground wire leakage in the power transmission line, and the information of the ground wire leakage is transmitted to the display screen connected to the metering chip through the metering chip for display.

[0057] The beneficial effects of the present invention are that, compared with the prior art, the technical effects of the present invention include:

[0058] The present invention triggers leakage detection through the zero-sequence current safety threshold, combines the three-phase phase deviation threshold to identify the fundamental phase deviation type three-phase unbalanced leakage, uses the three-phase total harmonic distortion rate average value threshold to identify the harmonic interference type three-phase unbalanced leakage, and identifies the ground wire leakage through comprehensive judgment, ultimately achieving accurate distinction of the leakage type of the high-power power distribution unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a flow chart of the electronic leakage intelligent monitoring method for a high-power power distribution unit described in the present invention. DETAILED DESCRIPTION

[0060] To make the objectives, technical solutions, and advantages of the present invention more clear, the following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely express the technical solutions of the present invention. The embodiments expressed in this application are only some embodiments of the present invention, not all embodiments. Based on the spirit of the present invention, other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0061] like Figure 1 As shown, the present invention provides an intelligent monitoring method for electronic leakage of a high-power power distribution unit, comprising:

[0062] Step 1: Collect data from the high-power power distribution unit;

[0063] In a preferred but non-limiting embodiment of the present invention, step 1 specifically comprises:

[0064] Step 1-1: Construct an electronic leakage intelligent monitoring device for a high-power power distribution unit, that is, connect the three contactors and four current sensors of the high-power power distribution unit to the metering chip, the three contactors are respectively connected to the three transmission lines, three of the four current sensors are also respectively connected to the three transmission lines, the three transmission lines are respectively connected to the three phases of the three-phase output socket of the high-power power distribution unit, and the remaining current sensor of the four current sensors is connected to the ground wire of the three-phase output socket of the high-power power distribution unit; the three phases are phase A, phase B and phase C.

[0065] Step 1-2: Four current sensors respectively and synchronously collect the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket in real time. The sampling frequency of the four current sensors can be 10kHz, and the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket are transmitted to the metering chip.

[0066] Step 2: The metering chip of the high-power power distribution unit processes the A-phase current, B-phase current, C-phase current, and ground wire current transmitted from the three-phase output socket;

[0067] In a preferred but non-limiting embodiment of the present invention, step 2 specifically comprises:

[0068] The metering chip of the high-power power distribution unit filters the transmitted A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, that is, it uses a mean filtering algorithm to remove high-frequency interference signals in the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, and transmits the filtered A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket to the processing module of the metering chip.

[0069] Step 3: The processing module of the metering chip calculates the zero-sequence current based on the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket after filtering according to the improved algorithm;

[0070] In a preferred but non-limiting embodiment of the present invention, step 3 specifically comprises:

[0071] The current zero-sequence current calculation formula (zero-sequence current = phase A current + phase B current + phase C current) does not consider the effects of three-phase current phase deviation, harmonic interference, and ground wire current coupling, resulting in insufficient detection accuracy in three-phase unbalanced or complex leakage scenarios. In light of the structural characteristics of high-power power distribution units (such as components such as current sensors and metering chips), the following zero-sequence current calculation formula with an improved algorithm is proposed and implemented:

[0072] ;

[0073] in Indicates the zero-sequence current calculated according to the improved algorithm. The zero-sequence current calculated according to the improved algorithm reflects the comprehensive leakage situation of the three transmission lines and the grounding wire of the three-phase output socket. The unit is ampere (A); 、 and Respectively represent the fundamental current RMS value of phase A, phase B, and phase C of the three-phase output socket. The fundamental current RMS value of phase A, phase B, and phase C of the three-phase output socket are the phase A current, phase B current, and phase C current of the three-phase output socket after filtering, respectively, and the unit is ampere (A); 、 and Respectively represent the fundamental phase angles of the filtered phase A, phase B, and phase C currents of the three-phase output socket, reflecting the fundamental phase angles of each phase current. These are obtained by analyzing the waveform data of the filtered phase A, phase B, and phase C currents of the three-phase output socket by the processing module of the metering chip, and are expressed in degrees (°). 、 and They represent the effective value of the total harmonic current of phase A, phase B, and phase C of the three-phase output socket, respectively. 、 and The sum of the higher harmonic components excluding the fundamental wave in a preset number of filtered time series data of the phase A current of the three-phase output socket, a preset number of filtered time series data of the phase B current of the three-phase output socket, and a preset number of filtered time series data of the phase C current of the three-phase output socket, respectively. The higher harmonic components are obtained by performing Fourier transform on the preset number of filtered time series data of the phase A current of the three-phase output socket, the preset number of filtered time series data of the phase B current of the three-phase output socket, or the preset number of filtered time series data of the phase C current of the three-phase output socket by the processing module of the metering chip, and the unit of the higher harmonic components is ampere (A); Indicates the effective value of the ground wire current of the three-phase output socket. That is, the ground wire current after filtering, in amperes (A); Indicates the fundamental current correction coefficient, with a value range of 0.8-1.2, which is used to compensate for the influence of the three-phase current phase deviation on the fundamental zero-sequence component; Indicates the harmonic current correction factor, with a value range of 0.3-0.5. It is used to quantify the contribution of harmonic current to zero-sequence current (because harmonic leakage may exist independently of fundamental leakage). It can be preset or remotely configured via button 54; It represents the ground wire coupling coefficient, with a value range of 0.6-0.9. It is used to convert the ground wire leakage current into the zero-sequence current, solving the problem that the ground wire current detected alone is easily affected by three-phase imbalance.

[0074] Compared with the traditional zero-sequence current calculation formula (zero-sequence current = phase A current + phase B current + phase C current), this zero-sequence current calculation formula with an improved algorithm adds phase angle correction, harmonic component inclusion, and ground wire coupling terms. It can:

[0075] Accurately identify phase deviation leakage caused by asymmetric three-phase load (through and phase angle ); Capture nonlinear leakage caused by high-order harmonics (through and ); Integrate the ground wire current information to avoid the ground wire leakage being masked by three-phase imbalance (through and ), which can further provide more complete protection against leakage.

[0076] Through the collaborative calculation of the processing module of the metering chip, the real-time operation of the formula can be realized to meet the dynamic monitoring needs of the high-power power distribution unit.

[0077] In a preferred but non-limiting embodiment of the present invention, in step 3, 、 and The calculation formula is:

[0078] ;

[0079] in Indicates the amplitude of the sinusoidal component of the A-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the value of the phase A current of the three-phase output socket after filtering is as follows: applying Fourier transform to a preset number of time series data (waveform data) of the phase A current, including the phase A current of the three-phase output socket after filtering, to obtain the amplitude of the sinusoidal component of the phase A current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the A-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the cosine component amplitude of the phase A current of the three-phase output socket after the filtering process is as follows: applying Fourier transform to a preset number of time series data (waveform data) of the phase A current, including the phase A current of the three-phase output socket after the filtering process, to obtain the cosine component amplitude of the phase A current of the three-phase output socket after the filtering process; Indicates the amplitude of the sinusoidal component of the B-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the value of the sinusoidal component of the B-phase current of the three-phase output socket after filtering is as follows: applying Fourier transform to a preset number of B-phase current time series data (waveform data) including the B-phase current of the three-phase output socket after filtering, thereby obtaining the amplitude of the sinusoidal component of the B-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the B-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the cosine component amplitude of the B-phase current of the three-phase output socket after the filtering process is as follows: applying Fourier transform to a preset number of B-phase current time series data (waveform data) including the B-phase current of the three-phase output socket after the filtering process, thereby obtaining the cosine component amplitude of the B-phase current of the three-phase output socket after the filtering process; Indicates the amplitude of the sinusoidal component of the C-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the value of the sine component of the C-phase current of the three-phase output socket after filtering is as follows: applying Fourier transform to a preset number of time series data (waveform data) of the C-phase current, including the C-phase current of the three-phase output socket after filtering, thereby obtaining the amplitude of the sine component of the C-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the C-phase current of the three-phase output socket after filtering (unit: A). The method for obtaining the cosine component amplitude of the C-phase current of the three-phase output socket after filtering is as follows: applying Fourier transform to a predetermined number of time series data (waveform data) of the C-phase current, including the C-phase current of the three-phase output socket after filtering, thereby obtaining the cosine component amplitude of the C-phase current of the three-phase output socket after filtering; Indicates the fundamental angular frequency of three-phase alternating current (unit: rad / s), The calculation formula is ,in The grid frequency (my country's standard is 50Hz) is the preset parameter of the processing module of the metering chip. Indicates the starting time (in seconds) for collecting the A-phase current, B-phase current, or C-phase current of the three-phase output socket. This time is determined by the processing module of the metering chip synchronously recording the sampling time of the current sensor.

[0080] In a preferred but non-limiting embodiment of the present invention, in step 3, The calculation formula is:

[0081] ;

[0082] in It represents the dimensionless denominator, 0 represents the target phase mean, that is, in the ideal three-phase balanced state, the three-phase phase angles are symmetrically distributed (such as phase A 0°, phase B 120°, phase C 240°), and its mean deviation is theoretically 0. The constant 0.005 represents the correction coefficient of the phase deviation on the fundamental zero-sequence component, which is set based on the rated working phase range of the three-phase output socket (standard phase difference of 380V three-phase circuit); when the calculation result When it is less than 0.8, Take 0.8; When it is greater than 1.2, Take 1.2 (the value range is limited to match the calculation accuracy of the processing module of the metering chip).

[0083] By dynamically compensating for the phase deviation of the three-phase current caused by load asymmetry, the fundamental leakage detection deviation problem caused by ignoring the phase difference in traditional zero-sequence current calculation is solved, and the calculation accuracy of the fundamental zero-sequence component is improved by 15%-20%, which can further achieve the effect of more complete leakage protection.

[0084] In a preferred but non-limiting embodiment of the present invention, in step 3, The calculation formula is:

[0085] ;

[0086] in 、 and They respectively represent the total harmonic distortion rate of phase A, phase B, and phase C of the three-phase output socket (unit: %). The total harmonic distortion rate of phase A, phase B, and phase C of the three-phase output socket can be obtained by methods in the prior art, for example, by performing Fourier transform on a preset number of time series data of the phase A current of the three-phase output socket after filtering, a preset number of time series data of the phase B current of the three-phase output socket after filtering, or a preset number of time series data of the phase C current of the three-phase output socket after filtering; 0.3 represents the basic offset of the harmonic current correction coefficient, which represents a pre-set basic correction value when the three-phase total harmonic distortion rate is ideal (which can be understood as minimal harmonic influence), which is used to ensure the rationality of the initial calculation of the formula, so that There is a reference value, which can be used to make basic corrections to the influence of harmonic current when the harmonic interference is weak; 0.2 represents the proportional coefficient, which is used to adjust the total harmonic distortion rate. The degree of influence determines that when the average value of the three-phase total harmonic distortion rate changes by a certain proportion, The magnitude of the change is used to convert the total harmonic distortion rate to Connect, let It can be dynamically adjusted according to the harmonic situation; 3×50% represents the preset three-phase total harmonic distortion rate reference benchmark value, which is generally determined based on the industry's general understanding of harmonic interference, the acceptable harmonic level of equipment such as large-power power distribution units (PDUs) during normal operation, etc. It serves as the denominator in the formula for normalizing the total harmonic distortion rate, allowing total harmonic distortion rates of different sizes to participate in a relatively unified manner Calculation makes the calculation results more stable and reasonable, which is convenient for adapting to the actual operation scene of the device; when the calculation results When it is less than 0.3, Take 0.3; When it is greater than 0.5, Take 0.5 (the value range is limited to match the calculation accuracy of the processing module of the metering chip).

[0087] Combined with the three-phase total harmonic distortion rate, dynamic adjustment The numerical value makes the zero-sequence current calculation more in line with the actual harmonic interference situation and improves the accuracy of leakage identification of high-power power distribution units.

[0088] In a preferred but non-limiting embodiment of the present invention, in step 3, The calculation formula is:

[0089] ;

[0090] in In the calculation of zero-sequence current, 0.6 represents the grounding wire coupling coefficient The lower limit value of , which represents the basic weight of the impact of the grounding wire current on the zero-sequence current. It means the contribution of the grounding wire current to the zero-sequence current calculation when the impact of the grounding wire current on the leakage judgment is minimal. For example, when the three-phase load is almost completely balanced and the grounding wire current is extremely small, the impact of the grounding wire current on the zero-sequence current is calculated according to The weight of the grounding wire current is used to participate in the calculation, ensuring that even if the grounding wire current is very small, its influence can be reasonably reflected in the zero-sequence current calculation, avoiding the misjudgment of leakage caused by excessive neglect of the grounding wire current. 0.3 represents an adjustment coefficient, which is used to adjust the effects of certain factors (such as the imbalance of three-phase current, the proportional relationship between the grounding wire current and the three-phase current, etc.) For example, if The calculation of is related to the three-phase current imbalance. 0.3 may determine that when the three-phase current imbalance changes to a certain degree, The corresponding change amplitude is used to dynamically adjust the weight of the grounding wire current in the zero-sequence current calculation. When it is less than 0.6, Take 0.6; When it is greater than 0.9, Take 0.9 (the value range is limited to match the calculation accuracy of the processing module of the metering chip).

[0091] In a three-phase circuit, the ground wire current not only reflects the three-phase imbalance, but may also contain complex components such as harmonics. When the three-phase load is unbalanced or there are harmonic currents, current will flow through the ground wire. The grounding current can be reasonably included in the zero-sequence current calculation, so that the calculated zero-sequence current can more accurately reflect the line leakage situation. For example, when the three-phase load is seriously unbalanced, the grounding current increases. By weighting the grounding wire current, the calculated zero-sequence current can more accurately reflect the actual leakage state, avoiding misjudgment or missed judgment of leakage caused by ignoring the grounding wire current.

[0092] Step 4: The processing module of the metering chip identifies three-phase unbalanced leakage or ground wire leakage based on the zero-sequence current;

[0093] In a preferred but non-limiting embodiment of the present invention, step 4 specifically comprises:

[0094] Step 4-1: The processing module of the metering chip processes the zero-sequence current according to the preset threshold value. Conduct leakage identification;

[0095] In a preferred but non-limiting embodiment of the present invention, step 4-1 specifically comprises:

[0096] Preset threshold 1 This is the zero-sequence current safety threshold, which is used to determine whether there is a significant leakage risk in the line. It is set based on the rated load of the high-power power distribution unit, industry safety standards (such as GB 13955-2017), and the leakage withstand capability of the high-power power distribution unit. It is usually set to the rated leakage operation current of the high-power power distribution unit (for example, 30mA, which needs to be adjusted according to the model and application scenario of the high-power power distribution unit).

[0097] like , determine that there is no significant leakage risk in the transmission line and return to the real-time monitoring state;

[0098] like , determining that there is a leakage risk in the transmission line, triggering the subsequent leakage type identification process and the metering chip controlling the three contactors to disconnect, thereby ensuring the safe operation of the high-power power distribution unit and avoiding damage caused by leakage;

[0099] The subsequent leakage type identification process is triggered as follows:

[0100] Step 4-2: According to the preset threshold Identify three-phase unbalanced leakage with fundamental wave phase deviation;

[0101] In a preferred but non-limiting embodiment of the present invention, step 4-2 specifically comprises:

[0102] Preset threshold 2 The three-phase phase deviation threshold is the key threshold for identifying fundamental phase deviation-type three-phase unbalanced leakage. It is set based on the standard phase accuracy of a 380V three-phase circuit (the ideal symmetrical phase difference is 0° for phase A, 120° for phase B, and 240° for phase C). For example, It can be set to 5° (reflecting the phase shift threshold caused by three-phase load asymmetry).

[0103] Calculate the deviation between the actual phase difference of the three phases and the ideal phase difference 、 and :

[0104] ;

[0105] If exists 、 or , and the fundamental component in the zero-sequence current accounts for (the fundamental component of the zero-sequence current / The fundamental component of the zero-sequence current is obtained by combining the current zero-sequence current and a preset number of adjacent zero-sequence currents obtained previously into corresponding time series data, and then applying Fourier transform to transform the time series data to obtain the corresponding fundamental component. , it is determined that there is a fundamental wave phase deviation type three-phase unbalanced leakage in the transmission line, and the message of the fundamental wave phase deviation type three-phase unbalanced leakage is transmitted to a display screen connected to the metering chip through the metering chip for display, so as to express the recognition that there is a fundamental wave phase deviation type three-phase unbalanced leakage in the transmission line.

[0106] Step 4-3: According to the preset threshold Identify three-phase unbalanced leakage caused by harmonic interference;

[0107] In a preferred but non-limiting embodiment of the present invention, step 4-3 specifically comprises:

[0108] Preset threshold three That is, the three-phase total harmonic distortion rate average value threshold, which is used to identify the key threshold of harmonic interference type three-phase unbalanced leakage, and is set based on the harmonic level during normal operation of the high-power power distribution unit. For example, Can be set to 10% (reflecting the critical value of high-order harmonic interference).

[0109] Calculate the average value of three-phase total harmonic distortion :

[0110] ;

[0111] like , and the proportion of harmonic components in zero-sequence current (harmonic components of zero-sequence current / The harmonic components of the zero-sequence current are obtained by forming the current zero-sequence current and a preset number of adjacent zero-sequence currents obtained previously into corresponding time series data, and then applying Fourier transform to transform the time series data to obtain the corresponding harmonic components. , it is determined that there is harmonic interference type three-phase unbalanced leakage in the transmission line, and the information of the harmonic interference type three-phase unbalanced leakage is transmitted to the display screen connected to the metering chip through the metering chip for display, so as to express the recognition that there is harmonic interference type three-phase unbalanced leakage in the transmission line.

[0112] Step 4-4: Comprehensively judge and identify ground wire leakage.

[0113] In a preferred but non-limiting embodiment of the present invention, step 4-4 specifically comprises:

[0114] Ground wire leakage identification can be combined with the above threshold and ground wire current characteristics: When the following three conditions are met:

[0115] Condition 1: Effective value of the ground wire current of the three-phase output socket ( is the rated current of the ground wire, which can be used as the derived threshold);

[0116] Condition 2: Ground wire coupling ratio ( ,in )≥50%;

[0117] Condition three: 、 and (Exclude the dominant factor of three-phase imbalance);

[0118] The system then determines that a ground wire leakage exists on the transmission line, and transmits the ground wire leakage information to a display screen connected to the metering chip via the metering chip, indicating that a ground wire leakage exists on the transmission line. The high-power power distribution unit is a three-phase output intelligent PDU.

[0119] The beneficial effects of the present invention are that, compared with the prior art, the technical effects of the present invention include:

[0120] The present invention triggers leakage detection through the zero-sequence current safety threshold, combines the three-phase phase deviation threshold to identify the fundamental phase deviation type three-phase unbalanced leakage, uses the three-phase total harmonic distortion rate average value threshold to identify the harmonic interference type three-phase unbalanced leakage, and identifies the ground wire leakage through comprehensive judgment, ultimately achieving accurate distinction of the leakage type of the high-power power distribution unit.

[0121] 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, those skilled in the art should understand that the specific implementation methods of the present invention can still be modified or replaced with equivalents, and any modifications or equivalent replacements that do not deviate from the spirit and scope of the present invention should be covered within the protection space of the claims of the present invention.

Claims

1. An intelligent monitoring method for electronic leakage of a high-power power distribution unit, characterized in that: include: Step 1: Collect data from the high-power power distribution unit; Step 2: The metering chip of the high-power power distribution unit processes the A-phase current, B-phase current, C-phase current, and ground wire current transmitted from the three-phase output socket; Step 3: The processing module of the metering chip calculates the zero-sequence current based on the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket after filtering according to the improved algorithm; Step 4: The processing module of the metering chip identifies three-phase unbalanced leakage and ground wire leakage based on the zero-sequence current; Step 3 specifically includes: The following zero-sequence current calculation formula with an improved algorithm is implemented: ； in Indicates the zero-sequence current calculated according to the improved algorithm; 、 and They represent the effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket respectively. The effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket are the effective value of the fundamental current of phase A, phase B, and phase C of the three-phase output socket respectively after filtering; 、 and They respectively represent the fundamental wave phase angle of the A-phase current, the fundamental wave phase angle of the B-phase current, and the fundamental wave phase angle of the C-phase current of the three-phase output socket after filtering; 、 and Respectively represent the total harmonic current RMS value of phase A, phase B, and phase C of the three-phase output socket; Indicates the effective value of the ground wire current of the three-phase output socket. That is, the ground wire current after filtering; Indicates the fundamental current correction coefficient; Indicates the harmonic current correction factor; It represents the ground wire coupling coefficient; Step 4 specifically includes: Step 4-1: The processing module of the metering chip processes the zero-sequence current according to the preset threshold value. Conduct leakage identification; Step 4-1 specifically includes: like , it is determined that there is no significant leakage risk in the transmission line; like , it is determined that there is a leakage risk in the transmission line, triggering the subsequent leakage type identification process and the metering chip controls the three contactors to disconnect; The subsequent leakage type identification process is triggered as follows: Step 4-2: According to the preset threshold Identify three-phase unbalanced leakage with fundamental wave phase deviation; Step 4-3: According to the preset threshold Identify three-phase unbalanced leakage caused by harmonic interference; Step 4-4: Comprehensively judge and identify ground wire leakage.

2. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 1 is characterized in that: Step 1 specifically includes: Step 1-1: Construct an intelligent electronic leakage monitoring device for a high-power power distribution unit, namely, connect the three contactors and four current sensors of the high-power power distribution unit to the metering chip, respectively connect the three contactors to three transmission lines, and connect three of the four current sensors to the three transmission lines. The three transmission lines are respectively connected to three phases of the three-phase output socket of the high-power power distribution unit, and the remaining current sensor of the four current sensors is connected to the ground wire of the three-phase output socket of the high-power power distribution unit. Step 1-2: The four current sensors respectively and synchronously collect the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket in real time, and transmit the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket to the metering chip.

3. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 2, characterized in that: Step 2 specifically includes: The metering chip of the high-power power distribution unit filters the transmitted A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, that is, it uses a mean filtering algorithm to remove high-frequency interference signals in the A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket, and transmits the filtered A-phase current, B-phase current, C-phase current and ground wire current of the three-phase output socket to the processing module of the metering chip.

4. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 3 is characterized in that: In step 3, 、 and The calculation formula is: ； in Indicates the amplitude of the sinusoidal component of the A-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the A-phase current of the three-phase output socket after filtering; Indicates the amplitude of the sinusoidal component of the B-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the B-phase current of the three-phase output socket after filtering; Indicates the amplitude of the sinusoidal component of the C-phase current of the three-phase output socket after filtering. Indicates the amplitude of the cosine component of the C-phase current of the three-phase output socket after filtering; It represents the fundamental angular frequency of three-phase alternating current. The calculation formula is ,in is the grid frequency, Indicates the start time of collecting the A-phase current, B-phase current, or C-phase current of the three-phase output socket.

5. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 4, characterized in that: In step 3, The calculation formula is: ; in represents the dimensionless denominator, 0 represents the target phase mean, and the constant 0.005 represents the correction coefficient of the phase deviation on the fundamental zero-sequence component; when the calculation result When it is less than 0.8, Take 0.8; When it is greater than 1.2, Take 1.

2.

6. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 5, characterized in that: In step 3, The calculation formula is: ; in 、 and Respectively represent the total harmonic distortion rate of phase A, phase B, and phase C of the three-phase output socket; 0.3 represents the basic offset of the harmonic current correction coefficient; 0.2 represents the proportional coefficient; 3×50% represents the preset three-phase total harmonic distortion reference value; when the calculation result When it is less than 0.3, Take 0.3; When it is greater than 0.5, Take 0.

5.

7. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 6, characterized in that: In step 3, The calculation formula is: ; in , 0.6 represents the ground wire coupling coefficient The lower limit value, 0.3 represents an adjustment coefficient, when the calculation result When it is less than 0.6, Take 0.6; When it is greater than 0.9, Take 0.

9.

8. The electronic leakage intelligent monitoring method for a high-power power distribution unit according to claim 7, characterized in that: Step 4-2 specifically includes: Calculate the deviation between the actual phase difference of the three phases and the ideal phase difference 、 and : ; If exists 、 or , and the fundamental component in the zero-sequence current accounts for , determining that there is a fundamental wave phase deviation type three-phase unbalanced leakage in the transmission line, and transmitting the message of the fundamental wave phase deviation type three-phase unbalanced leakage to a display screen connected to the metering chip through the metering chip for display; Step 4-3 specifically includes: Calculate the average value of three-phase total harmonic distortion : ； like , and the proportion of harmonic components in zero-sequence current , determining that there is harmonic interference type three-phase unbalanced leakage in the transmission line, and transmitting the information of the harmonic interference type three-phase unbalanced leakage to a display screen connected to the metering chip through the metering chip for display; Step 4-4 specifically includes: when When the following three conditions are met: Condition 1: Effective value of the ground wire current of the three-phase output socket ; Condition 2: The proportion of ground wire coupling items is ≥50%; Condition three: 、 and ; It is determined that there is ground wire leakage in the power transmission line, and the information of the ground wire leakage is transmitted to the display screen connected to the metering chip through the metering chip for display.

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