Power grid harmonic phase analysis method, system and device

Abstract

The present invention relates to a method, system and device for harmonic phase analysis of a power grid. The method comprises: obtaining a voltage waveform signal of a concerned bus and a current waveform signal on a power user feeder; dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepting a preset number of cycles of the voltage waveform signal and the current waveform signal; performing a fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of the voltage signal of each phase and the harmonic phasor of the current signal of each phase; obtaining the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and obtaining the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase; and performing analysis based on all phase data obtained within the statistical time. The above-mentioned method, system and device for harmonic phase analysis of a power grid can more accurately reflect the phase distribution of harmonic currents, and also have phase sequence fault tolerance.

Description

Technical Field

[0001] The present invention relates to the technical field of power quality analysis of power grids, and in particular to a method, system and device for analyzing harmonic phase of power grids. Background Art

[0002] Modern power supply requires high reliability, flexible control, and convenient application, but the problem of poor power quality caused by power system pollution has always existed: on the one hand, with the large-scale application of various new user loads, especially various power electronic devices with nonlinearity and harmonics, the power quality of the power grid has been adversely affected; on the other hand, users have higher and higher requirements for power supply reliability, especially many precision electronic equipment are widely used in power systems, and they are more and more sensitive to power supply quality. Therefore, it is urgent to strengthen the harmonic management of distribution networks.

[0003] Harmonic management of distribution network is an important basic work of modern power system and the guarantee of safe, economical and stable operation of power system. The main contents of harmonic management include load investigation, field test, analysis and treatment suggestions, and formulation and implementation of harmonic management methods. It mainly includes: 1) obtaining corresponding harmonic data through field investigation and testing; 2) using corresponding technical means to perform harmonic analysis; 3) proposing treatment measures based on the analysis results, etc.

[0004] An important part of harmonic analysis is the analysis of harmonic phase distribution characteristics. Currently, the harmonic impedance angle is used to characterize the phase characteristics of harmonic current, but it has the following problems:

[0005] (1) Since the harmonic voltage at the point of interest is affected by the background harmonic voltage and the load harmonic current, using the harmonic voltage as a reference for the phase distribution characteristics of the typical load harmonic current will cause a large deviation in the phase distribution of the harmonic current. Therefore, the harmonic impedance angle cannot accurately characterize the phase characteristics of the harmonic current.

[0006] (2) The harmonic impedance angle cannot have phase sequence fault tolerance. The ABC phases in different low-voltage power loads may not be completely corresponding, that is, the ABC phases of one distribution transformer may correspond to the BCA phases of another distribution transformer. If the harmonic current phase distribution does not have phase sequence fault tolerance, if the B phase data is mistakenly regarded as the A phase data, incorrect results may be obtained. Summary of the invention

[0007] Based on this, a method, system and device for power grid harmonic phase analysis are provided to address the problems existing in using harmonic impedance angle to characterize the phase characteristics of phase harmonic current.

[0008] A method for analyzing harmonic phase of a power grid, the method comprising:

[0009] Obtaining a voltage waveform signal of a concerned busbar and a current waveform signal on a power user feeder;

[0010] The statistical time is divided into a plurality of calculation windows; and within each calculation window, a preset number of cycles of the voltage waveform signal and the current waveform signal are intercepted;

[0011] Performing a fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal;

[0012] Obtain the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing moment as a reference, and obtain the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase;

[0013] The analysis is performed based on all phase data acquired within the statistical time.

[0014] In one of the embodiments, the calculation window is divided into equal parts according to fixed time lengths within the statistical time.

[0015] In one embodiment, the obtaining of the voltage waveform signal of the busbar of interest and the current waveform signal on the power user feeder includes:

[0016] The voltage waveform signal and the current waveform signal are obtained by using a voltage transformer and a current transformer in cooperation with a data acquisition and monitoring control system.

[0017] In one of the embodiments, the sampling frequency of each channel of the voltage waveform signal and the current waveform signal is not less than 12.8 kHz.

[0018] In one embodiment, the preset number is 10.

[0019] In one embodiment, the step of obtaining the zero-crossing time of the rising edge of each phase fundamental voltage according to the harmonic phasor of each phase voltage signal includes:

[0020] At each current moment, determine whether the fundamental voltage phase angle of each phase meets the following conditions: the fundamental voltage phase angle at the previous moment is less than zero, and the fundamental voltage phase angle at the next moment is greater than zero;

[0021] If it is satisfied, the current time is the zero-crossing time.

[0022] In one embodiment, the fixed duration is 5 seconds.

[0023] In one embodiment, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

[0024] A power grid harmonic phase analysis system, comprising:

[0025] A signal acquisition module, used to acquire a voltage waveform signal of a concerned busbar and a current waveform signal on a power user feeder;

[0026] A waveform interception module, used for dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepting a preset number of cycles of the voltage waveform signal and the current waveform signal;

[0027] A harmonic phasor calculation module, used for performing a fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal;

[0028] A harmonic phase calculation module, used to obtain the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing moment as a reference, and obtain the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase;

[0029] The analysis module is used for performing analysis based on all phase data obtained within a statistical time.

[0030] A power grid harmonic phase analysis device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0031] The above-mentioned power grid harmonic phase analysis method, system and device can more accurately reflect the phase distribution of harmonic current by obtaining the phase of each harmonic of each phase with the zero crossing point of the rising edge of the fundamental voltage as the reference benchmark. The phase of each harmonic current of each phase is obtained corresponding to the corresponding fundamental voltage of each phase. For example, the phase of each harmonic of the harmonic current phase A is obtained according to the zero crossing point of the rising edge of the fundamental voltage phase A, which will not be affected by the phase sequence identification error, and therefore has phase sequence fault tolerance capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1a A flow chart of a method for analyzing power grid harmonic phase according to an embodiment;

[0033] Figure 1b To calculate the relationship between statistical time, calculation window and intercepted cycles;

[0034] Figure 2a It is the phase distribution diagram of the third harmonic current;

[0035] Figure 2b It is the phase distribution diagram of the 5th harmonic current;

[0036] Figure 2c It is the phase distribution diagram of the 7th harmonic current;

[0037] Figure 3 A block diagram of a power grid harmonic phase analysis system according to an embodiment. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0040] Figure 1a FIG. 1 is a flow chart of a method for analyzing harmonic phase of a power grid according to an embodiment of the present invention. Figure 1a As shown, the method comprises:

[0041] Step S102: Acquire the voltage waveform signal of the busbar of interest and the current waveform signal on the power user feeder.

[0042] The busbar of interest is the busbar whose harmonic phase characteristics are to be analyzed, and the power user feeder is the distribution line distributed from the busbar of interest and connected to the user-side load.

[0043] Specifically, the voltage waveform signal and the current waveform signal may be acquired by using a potential transformer (PT) and a current transformer (CT) in conjunction with a supervisory control and data acquisition system (SCADA).

[0044] SCADA is a data collection, monitoring and control system for production systems with long distribution distances and dispersed production units. SCADA plays an important role in telecontrol systems. It can monitor and control the operating equipment on site to achieve various functions such as data collection, equipment control, measurement, parameter adjustment, and various signal alarms. The important components of SCADA include Remote Terminal Unit (RTU) and Feedback Terminal Unit (FTU).

[0045] Voltage transformers and current transformers are voltage and current measuring instruments made using the principle of mutual inductance. To facilitate digital processing, the collected voltage waveform signals and current waveform signals are high-frequency sampling signals. In one embodiment, the three-phase voltage waveform signals of the busbar and the three-phase current waveform signals on the power user feeder are collected, and the sampling frequency of each phase of the voltage waveform signals and current waveform signals is not less than 12.8kHz.

[0046] In this embodiment, the voltage waveform signal is recorded as u k (t), the current signal waveform is recorded as i k (t). k represents the three phases A, B, and C in the distribution network, and t represents time.

[0047] Step S104: Divide the statistical time into a plurality of calculation windows; and in each calculation window, intercept a preset number of cycles of the voltage waveform signal and the current waveform signal.

[0048] In order to analyze the harmonic phase characteristics, it is necessary to collect signal waveforms for analysis and calculation within a longer statistical time. In one embodiment, the calculation window is divided into equal parts according to a fixed time length within the statistical time. That is, interception and calculation are performed once according to a fixed time length. For example, if the statistical time is 12 hours, if interception and calculation are performed every 5 seconds, then 8640 interceptions and calculations are required.

[0049] The calculation window refers to the calculation time period. In this step, a preset number of cycles of the voltage waveform signal and the current waveform signal are intercepted within at least one calculation time period. A cycle refers to a waveform of a signal period. For example, for industrial frequency voltage, the voltage frequency is 50Hz, and a signal period is 0.02 seconds. The preset number depends on the situation, for example, the number of intercepted cycles is determined based on computing power, computing accuracy requirements, etc. In one embodiment, 10 cycles, that is, waveform signals with a duration of 200 milliseconds, can be intercepted from the voltage waveform signal and the current waveform signal respectively. The relationship between the statistical time, the calculation window and the intercepted cycles is as follows: Figure 1b shown.

[0050] Step S106: performing fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal.

[0051] Taking 10 cycles as an example, within each calculation window, the 10 cycle signals are subjected to Fast Fourier Transform (FFT), thereby obtaining a set of voltage harmonic phasors and a set of current harmonic phasors.

[0052] Within the statistical time, each calculation can obtain a set of voltage harmonic phasors and a set of current harmonic phasors. Therefore, a total of N sets of voltage harmonic phasors and N sets of current harmonic phasors can be obtained. In this embodiment, the nth set of voltage harmonic phasors is recorded as The nth group of current harmonic phasors is recorded as Where n = 1, 2...N. k represents the three phases A, B, and C in the distribution network, and h represents the harmonic order, which can be 3, 5, 7, etc. It can be understood that and are all discrete time series about time t. Their amplitude and phase angle can be expressed as and

[0053] Step S108: Obtain the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing moment as a reference benchmark, and obtain the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase.

[0054] The fundamental wave is a wave with the same frequency as the signal frequency. For convenience, h = 1 is used to represent the fundamental wave. Then the zero-crossing moment of each phase fundamental wave is the moment when the phase angle of each phase fundamental wave voltage is 0. For example, the phase fundamental wave voltage phase angle of 0 can be expressed as

[0055] In one embodiment, the step of obtaining the zero-crossing time of the rising edge of each phase fundamental voltage according to the harmonic phasor of each phase voltage signal includes:

[0056] At each current moment, it is determined whether the fundamental voltage phase angle of each phase meets the following conditions: the fundamental voltage phase angle at the previous moment is less than zero, and the fundamental voltage phase angle at the next moment is greater than zero; if so, the current moment is a zero-crossing moment.

[0057] Taking phase A as an example, the formula is:

[0058] t 0 -1:

[0059] t 0 +1:

[0060] Find the zero-crossing time t of the rising edge of each phase fundamental voltage 0 Afterwards, the h-order harmonic phases of the same group of current signals with the same phase of the harmonic phasors are found, and the h-order harmonic phases are the harmonic phases required by the present application.

[0061] That is: through Get the phase angle of the fundamental voltage of phase A The time t 0Then, find the harmonic current of phase A h Middle time t 0 The corresponding phase That is, the phase of the hth harmonic current of phase A in the nth phasor array with the zero crossing point of the rising edge of the fundamental voltage of phase A as the reference.

[0062] Repeat the above steps for phase B and phase C to obtain the hth harmonic current phase of phase B and phase C in the nth phase array. In one embodiment, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

[0063] Step S110: performing analysis based on all phase data obtained within the statistical time.

[0064] After processing each group of phasor arrays in n=1, 2...N, the harmonic phase data in all calculation windows can be obtained. All the obtained harmonic phase data can be used to analyze the harmonic phase characteristics of the power grid, thereby providing a basis for solving harmonic pollution and improving the quality of electric energy. In one embodiment, the method for analyzing the harmonic phase is to draw a harmonic current phase distribution diagram. For example, for the 3rd harmonic current, the 3rd harmonic current phase data obtained in each calculation window is represented in the phase distribution diagram; for the 5th harmonic current, the 5th harmonic current phase data obtained in each calculation window is represented in the phase distribution diagram; and so on.

[0065] For better explanation, the following is a detailed description using a public transformer residential power load as an example:

[0066] (1) Use voltage transformer, current transformer and SCADA system to obtain the voltage waveform signal u of the public transformer bus k (t) and the current waveform signal i of the power user feeder k (t), the sampling frequency of each channel waveform signal is 12.8kHz.

[0067] (2) The total statistical time is 12 hours, and the fast Fourier transform (FFT) calculation interval is 5 seconds. Then N is 8640 within the statistical time, that is, a total of 8640 sets of voltage waveform signals and current waveform signals of each phase are collected. In each set of voltage waveform signals and current waveform signals of each phase, the collected A phase voltage waveform signal u A (t) and each phase current waveform signal i k (t) 10 cycles are intercepted respectively and transformed by fast Fourier transform (FFT). The fundamental voltage phasor of phase A on the public transformer bus is obtained. And the 3rd, 5th and 7th harmonic current phasors of each phase power user feeder Where k = A, B, C and h = 3, 5, 7.

[0068] (3) For the nth phasor array, find the fundamental voltage phase angle of phase A The time t 0 It is used as the zero-crossing point of the rising edge of the fundamental voltage of phase A and is used as the reference benchmark.

[0069] (4) Let k = A. In the nth phasor array, find the hth harmonic current of phase A. Middle time t 0 Corresponding That is, the phase of the hth harmonic current of phase A in the nth phasor array with the zero crossing point of the rising edge of the fundamental voltage of phase A as the reference.

[0070] (5) Assume k = B and k = C respectively, repeat step (4) to obtain the phase of the hth harmonic current of phase B and phase C in the nth array:

[0071] (6) Repeat steps (3), (4), and (5) until n = 8640. Based on the results, the 3rd, 5th, and 7th harmonic current phase distribution diagrams are obtained with the zero crossing point of the fundamental voltage of phase A as the reference. Figure 2a to Figure 2c shown.

[0072] Based on the same inventive concept, a power grid harmonic phase analysis system is also provided. Figure 3 As shown, a power grid harmonic phase analysis system 300 of an embodiment includes:

[0073] The signal acquisition module 302 is used to acquire the voltage waveform signal of the concerned bus and the current waveform signal on the power user feeder.

[0074] The busbar of interest is the busbar whose harmonic phase characteristics are to be analyzed, and the power user feeder is the distribution line distributed from the busbar of interest and connected to the user-side load.

[0075] Specifically, the voltage waveform signal and the current waveform signal may be acquired by using a potential transformer (PT) and a current transformer (CT) in conjunction with a supervisory control and data acquisition system (SCADA).

[0076] SCADA is a data collection, monitoring and control system for production systems with long distribution distances and dispersed production units. SCADA plays an important role in telecontrol systems. It can monitor and control the operating equipment on site to achieve various functions such as data collection, equipment control, measurement, parameter adjustment, and various signal alarms. The important components of SCADA include Remote Terminal Unit (RTU) and Feedback Terminal Unit (FTU).

[0077] Voltage transformers and current transformers are voltage and current measuring instruments made using the principle of mutual inductance. To facilitate digital processing, the collected voltage waveform signals and current waveform signals are high-frequency sampling signals. In one embodiment, the three-phase voltage waveform signals of the busbar and the three-phase current waveform signals on the power user feeder are collected, and the sampling frequency of each phase of the voltage waveform signals and current waveform signals is not less than 12.8kHz.

[0078] In this embodiment, the voltage waveform signal is recorded as u k (t), the current signal waveform is recorded as i k (t). Where k represents the three phases A, B, and C in the distribution network, and t represents time.

[0079] The waveform interception module 304 is used to divide the statistical time into a plurality of calculation windows; and in each calculation window, intercept a preset number of cycles of the voltage waveform signal and the current waveform signal.

[0080] In order to analyze the harmonic phase characteristics, it is necessary to collect signal waveforms for analysis and calculation within a longer statistical time. In one embodiment, the calculation window is divided into equal parts according to a fixed time length within the statistical time. That is, interception and calculation are performed once according to a fixed time length. For example, if the statistical time is 12 hours, if interception and calculation are performed every 5 seconds, then 8640 interceptions and calculations are required.

[0081] The calculation window is the calculation time period. In this step, a preset number of cycles of the voltage waveform signal and the current waveform signal are intercepted within at least one calculation time period. A cycle refers to a waveform of a signal period. For example, for industrial frequency voltage, the voltage frequency is 50Hz, then a signal period is 0.02 seconds. The preset number depends on the situation, for example, the number of intercepted cycles is determined according to computing power, computing accuracy requirements, etc. In one embodiment, 10 cycles, that is, waveform signals with a duration of 200 milliseconds, can be intercepted from the voltage waveform signal and the current waveform signal respectively.

[0082] The harmonic phasor calculation module 306 is used to perform fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal.

[0083] Taking 10 cycles as an example, within each calculation window, the 10 cycle signals are subjected to Fast Fourier Transform (FFT), thereby obtaining a set of voltage harmonic phasors and a set of current harmonic phasors.

[0084] Within the statistical time, each calculation can obtain a set of voltage harmonic phasors and a set of current harmonic phasors. Therefore, a total of N sets of voltage harmonic phasors and N sets of current harmonic phasors can be obtained. In this embodiment, the nth set of voltage harmonic phasors is recorded as The nth group of current harmonic phasors is recorded as Where n = 1, 2...N. k represents the three phases A, B, and C in the distribution network, and h represents the harmonic order, which can be 3, 5, 7, etc. It can be understood that and are all discrete time series about time t. Their amplitude and phase angle can be expressed as and

[0085] The harmonic phase calculation module 308 is used to obtain the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing moment as a reference benchmark to obtain the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase.

[0086] The fundamental wave is a wave with the same frequency as the signal frequency. For convenience, h = 1 is used to represent the fundamental wave. Then the zero-crossing moment of each phase fundamental wave is the moment when the phase angle of each phase fundamental wave voltage is 0. For example, the phase fundamental wave voltage phase angle of 0 can be expressed as

[0087] In one embodiment, the step of obtaining the zero-crossing time of the rising edge of each phase fundamental voltage according to the harmonic phasor of each phase voltage signal includes:

[0088] At each current moment, it is determined whether the fundamental voltage phase angle of each phase meets the following conditions: the fundamental voltage phase angle at the previous moment is less than zero, and the fundamental voltage phase angle at the next moment is greater than zero; if so, the current moment is a zero-crossing moment.

[0089] Taking phase A as an example, the formula is:

[0090] t 0 -1:

[0091] t 0+1:

[0092] Find the zero-crossing time t of the rising edge of each phase fundamental voltage 0 Afterwards, the h-order harmonic phases of the same group of current signals with the same phase of the harmonic phasors are found, and the h-order harmonic phases are the harmonic phases required by the present application.

[0093] That is: through Get the phase angle of the fundamental voltage of phase A The time t 0 Then, find the harmonic current of phase A h Middle time t 0 The corresponding phase That is, the phase of the hth harmonic current of phase A in the nth phasor array with the zero crossing point of the rising edge of the fundamental voltage of phase A as the reference.

[0094] Repeat the above steps for phase B and phase C to obtain the hth harmonic current phase of phase B and phase C in the nth phase array. In one embodiment, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

[0095] The analysis module 310 is used to perform analysis based on all phase data obtained within the statistical time.

[0096] After processing each group of phasor arrays in n=1, 2...N, the harmonic phase data in all calculation windows can be obtained. All the obtained harmonic phase data can be used to analyze the harmonic phase characteristics of the power grid, thereby providing a basis for solving harmonic pollution and improving the quality of electric energy. In one embodiment, the method for analyzing the harmonic phase is to draw a harmonic current phase distribution diagram. For example, for the 3rd harmonic current, the 3rd harmonic current phase data obtained in each calculation window is represented in the phase distribution diagram; for the 5th harmonic current, the 5th harmonic current phase data obtained in each calculation window is represented in the phase distribution diagram; and so on.

[0097] Based on the same inventive concept, a power grid harmonic phase analysis device is also provided. The power grid harmonic phase analysis device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0098] The above-mentioned power grid harmonic phase analysis method, system and device can more accurately reflect the phase distribution of harmonic current by obtaining the phase of each harmonic of each phase with the zero crossing point of the rising edge of the fundamental voltage as the reference benchmark. The phase of each harmonic current of each phase is obtained corresponding to the corresponding fundamental voltage of each phase. For example, the phase of each harmonic of the harmonic current phase A is obtained according to the zero crossing point of the rising edge of the fundamental voltage phase A, which will not be affected by the phase sequence identification error, and therefore has phase sequence fault tolerance capability.

[0099] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for analyzing power grid harmonic phase. It is characterized in that The method includes: Obtaining a voltage waveform signal of a concerned busbar and a current waveform signal on a power user feeder; The statistical time is divided into a plurality of calculation windows; and within each calculation window, a preset number of cycles of the voltage waveform signal and the current waveform signal are intercepted; Performing a fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal; The zero-crossing moment of the rising edge of the fundamental voltage of each phase is obtained according to the harmonic phasor of the voltage signal of each phase, and the phase at the zero-crossing moment is used as a reference benchmark, and the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase is obtained according to the harmonic phasor of the current signal of each phase; that is: by Get the phase angle of the fundamental voltage of phase A Moment Then find phase A h Subharmonic current Middle time The corresponding phase ; and All are discrete time series about time t; and The amplitude and phase angle of and ; For the n Phase A in the group phase array h The phase of the subharmonic current is referenced to the zero-crossing point of the rising edge of the fundamental voltage of phase A; The analysis is performed based on all phase data acquired within the statistical time.

2. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The calculation window is equally divided into fixed time lengths within the statistical time.

3. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The step of obtaining a voltage waveform signal of a busbar of interest and a current waveform signal on a power user feeder includes: The voltage waveform signal and the current waveform signal are obtained by using a voltage transformer and a current transformer in cooperation with a data acquisition and monitoring control system.

4. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The sampling frequency of each channel of the voltage waveform signal and the current waveform signal is not less than 12.8 kHz.

5. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The preset number is 10.

6. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The step of obtaining the zero-crossing time of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase comprises: At each current moment, determine whether the fundamental voltage phase angle of each phase meets the following conditions: the fundamental voltage phase angle at the previous moment is less than zero, and the fundamental voltage phase angle at the next moment is greater than zero; If it is satisfied, the current time is the zero-crossing time.

7. The power grid harmonic phase analysis method according to claim 2, It is characterized in that The fixed duration is 5 seconds.

8. The power grid harmonic phase analysis method according to claim 1, It is characterized in that The harmonics are the third harmonic, the fifth harmonic and the seventh harmonic.

9. A power grid harmonic phase analysis system, include: A signal acquisition module, used to acquire a voltage waveform signal of a concerned busbar and a current waveform signal on a power user feeder; A waveform interception module, used for dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepting a preset number of cycles of the voltage waveform signal and the current waveform signal; A harmonic phasor calculation module, used for performing a fast Fourier transform on the preset number of cycles to obtain the harmonic phasor of each phase voltage signal and the harmonic phasor of each phase current signal; The harmonic phase calculation module is used to obtain the zero-crossing moment of the rising edge of the fundamental voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing moment as a reference benchmark to obtain the phase of each harmonic of the current signal of each phase at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase; that is: through Get the phase angle of the fundamental voltage of phase A Moment Then find phase A h Subharmonic current Middle time The corresponding phase ; and All are discrete time series about time t; and The amplitude and phase angle of and ; For the n Phase A in the group phase array h The phase of the subharmonic current is referenced to the zero-crossing point of the rising edge of the fundamental voltage of phase A; The analysis module is used for performing analysis based on all phase data obtained within a statistical time.

10. A power grid harmonic phase analysis device, It is characterized in that The method comprises a memory and a processor, wherein the memory stores a computer program, and wherein the processor implements the steps of the method according to any one of claims 1 to 8 when executing the computer program.

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