CN114460366A - Power grid harmonic phase analysis method, system and device - Google Patents

Abstract

The invention relates to a power grid harmonic phase analysis method, system and device. The method includes: acquiring the voltage waveform signal of the bus of interest and the current waveform signal on the power user feeder; dividing the statistical time into a plurality of calculation windows; and in each calculation window, analyzing the voltage waveform signal and the current waveform signal Intercept a preset number of cycles; perform fast Fourier transform on the preset number of cycles to obtain a harmonic phasor of each phase voltage signal and a harmonic phasor of each phase current signal; according to the each phase voltage signal The harmonic phasor of each phase obtains the zero-crossing moment of the rising edge of the fundamental voltage of each phase, and obtains the phase of each harmonic of each phase current signal at the zero-crossing moment of each phase according to the harmonic phasor of the current signal of each phase ; The analysis is based on all phase data acquired within the statistical time. The above-mentioned power grid harmonic phase analysis method, system and device can more accurately reflect the harmonic current phase distribution, and also have the capability of phase sequence fault tolerance.

Description

Power grid harmonic phase analysis method, system and device

technical field

The invention relates to the technical field of power quality analysis of power grids, in particular to a method, system and device for analyzing harmonic phases of power grids.

Background technique

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 various new user loads, especially nonlinear and harmonic The large-scale application of various power electronic devices has brought adverse effects on the power quality of the power grid; on the other hand, users have higher and higher requirements for the reliability of power supply, especially the large-scale use of many precision electronic equipment in the power system. Quality is becoming more and more sensitive. Therefore, it is urgent to strengthen the harmonic management of distribution network.

Harmonic management of distribution network is an important basic work of modern power system, and it is the guarantee of safe, economical and stable operation of power system. The main contents of harmonic management include load investigation, on-site test, analysis and put forward management suggestions, and formulate and implement harmonic management methods. It mainly includes: 1) Obtaining corresponding harmonic data through on-site investigation and testing; 2) Using corresponding technical means to carry out harmonic analysis; 3) Proposing control measures according to the analysis results.

The most important part of harmonic analysis is the analysis of harmonic phase distribution characteristics. At present, the harmonic impedance angle is used to characterize the phase characteristics of the harmonic current, but it has the following problems:

(1) Since the harmonic voltage of the point of interest is jointly affected by the background harmonic voltage and the load harmonic current, using the harmonic voltage as the reference for the phase distribution characteristics of the typical load harmonic current will make the phase distribution of the harmonic current appear relatively high. Therefore, the harmonic impedance angle cannot accurately characterize the phase characteristics of the harmonic current.

(2) The harmonic impedance angle cannot have phase sequence fault tolerance. The ABC three-phase in different low-voltage electrical loads may not be completely corresponding, that is, the ABC three-phase of one distribution transformer may correspond to the BCA three-phase of another distribution transformer. Sequence fault tolerance, if the B-phase data is mistakenly regarded as the A-phase data, wrong results may be obtained.

SUMMARY OF THE INVENTION

Based on this, in order to solve the problem of using the harmonic impedance angle to characterize the phase characteristics of the phase harmonic current, a method, system and device for analyzing the harmonic phase of a power grid are provided.

A power grid harmonic phase analysis method, the method includes:

Obtain the voltage waveform signal of the concerned bus and the current waveform signal of the power user feeder;

dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepting a preset number of cycles from the voltage waveform signal and the current waveform signal;

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;

Obtain 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, and take the phase at the zero-crossing time as a reference, and obtain each phase according to the harmonic phasor of the current signal of each phase. The phase of each harmonic of the phase current signal at the zero-crossing point of each phase;

Analysis is based on all phase data acquired within statistical time.

In one of the embodiments, the calculation window is divided equally into a fixed duration within the statistical time.

In one embodiment, the acquiring the voltage waveform signal of the concerned bus and the current waveform signal of the power user feeder includes:

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

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

In one of the embodiments, the preset number is 10.

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

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

If satisfied, the current time is the zero-crossing time.

In one of the embodiments, the fixed duration is 5 seconds.

In one of the embodiments, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

A power grid harmonic phase analysis system, comprising:

The signal acquisition module is used to acquire the voltage waveform signal of the concerned bus and the current waveform signal of the power user feeder;

a waveform interception module for dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepts a preset number of cycles from the voltage waveform signal and the current waveform signal;

a harmonic phasor calculation module, configured to perform fast Fourier transform on the preset number of cycles to obtain a harmonic phasor of each phase voltage signal and a harmonic phasor of each phase current signal;

The harmonic phase calculation module is used to obtain the zero-crossing point moment of the rising edge of the fundamental wave voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase of the zero-crossing point as a reference, according to the current signal of each phase The harmonic phasor of obtains the phase of each harmonic of each phase current signal at the zero-crossing time of each phase;

Analysis module for analysis based on all phase data acquired in statistical time.

A power grid harmonic phase analysis device includes 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.

The above power grid harmonic phase analysis method, system and device can more accurately reflect the harmonic current phase distribution by taking the zero-crossing point of the rising edge of the fundamental wave voltage as a reference to obtain the phase of each phase and each harmonic. The harmonic current phase of each phase is obtained corresponding to the fundamental wave voltage of each phase. For example, according to the zero-crossing point of the rising edge of phase A of the fundamental wave voltage, the phase of each harmonic current of phase A of the harmonic current is obtained, which will not be determined because of the phase sequence. It is affected by the error, so it has the capability of phase sequence fault tolerance.

Description of drawings

1a is a flowchart of a method for analyzing harmonic phase of a power grid according to an embodiment;

Figure 1b shows the relationship between statistical time, calculation window and intercepted cycles;

Figure 2a is a phase distribution diagram of the third harmonic current;

Figure 2b is the phase distribution diagram of the 5th harmonic current;

Figure 2c is the phase distribution diagram of the 7th harmonic current;

FIG. 3 is a block diagram of a power grid harmonic phase analysis system according to an embodiment.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

FIG. 1a is a flowchart of a method for analyzing harmonic phase of a power grid according to an embodiment. As shown in Figure 1a, the method includes:

Step S102: Acquire the voltage waveform signal of the bus of interest and the current waveform signal on the power user feeder.

Among them, the busbar of interest is the busbar whose harmonic phase characteristics are to be analyzed, and the power user feeder is the distribution line allocated from the busbar of interest, and is connected to the load on the user side.

Specifically, the voltage waveform signal and the current waveform signal can be obtained by using a potential transformer (PT) and a current transformer (CT) in conjunction with a data acquisition and supervisory control system (Supervisory Control And Data Acquisition System, SCADA). .

SCADA is a data acquisition, monitoring and control system for the production system with long distribution distance and scattered production units. SCADA occupies an important position in the telecontrol system, which can monitor and control the running equipment in the field to realize various functions such as data acquisition, equipment control, measurement, parameter adjustment and various signal alarms. An important part of SCADA includes remote terminal unit (Remote Terminal Unit, RTU), and feeder terminal unit (Feedback Terminal Unit, FTU).

Voltage transformers and current transformers are voltage and current measuring instruments made using the principle of mutual inductance. In order 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 signal of the concerned bus and the three-phase current waveform signal on the power user feeder are collected, and the sampling frequency of each phase of the voltage waveform signal and the current waveform signal is not less than 12.8 kHz.

In this embodiment, the voltage waveform signal is denoted as _uk (t), and the current signal waveform is denoted as _ik (t). Where k represents the three phases of A, B, and C in the distribution network, and t represents time.

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

In order to analyze the harmonic phase characteristics, it is necessary to collect the signal waveform for analysis and calculation in a long statistical time. In one of the embodiments, the calculation window is divided equally into a fixed duration within the statistical time. That is, one interception and calculation is performed according to a fixed duration. For example, the statistical time is 12 hours. If the interception and calculation are performed every 5 seconds, 8640 interceptions and calculations are required.

The calculation window is the calculation time period. In this step, a preset number of cycles are intercepted from the voltage waveform signal and the current waveform signal during at least one calculation period. A cycle is the waveform of one signal period. For example, for the power frequency voltage, if the voltage frequency is 50Hz, one signal period is 0.02 seconds. The preset number is determined according to the situation, for example, the number of intercepted cycles is determined according to the calculation capability, calculation accuracy requirements, and the like. In one of the embodiments, 10 cycles, ie, waveform signals with a duration of 200 milliseconds, may be intercepted from the voltage waveform signal and the current waveform signal, respectively. The relationship between statistical time, calculation window and intercepted cycles is shown in Figure 1b.

Step S106: Perform fast Fourier transform on the preset number of cycles to obtain a harmonic phasor of each phase voltage signal and a harmonic phasor of each phase current signal.

Taking 10 cycles as an example, in each calculation window, fast Fourier transform (Fast Fourier Transform, FFT) will be performed on the 10 cycle signals. A set of voltage harmonic phasors and a set of current harmonic phasors can be obtained respectively.

将第n组电流谐波相量记为

其中n＝1,2……N。k代表配电网中的A、B、C三相，h代表谐波次数，可以是3、5、7、……等。可以理解，

和

都是关于时间t的离散时间序列。其幅值相角的形式分别可表示为

和

In the statistical time, a set of voltage harmonic phasors and a set of current harmonic phasors can be obtained for each calculation. Therefore, a total of N groups of voltage harmonic phasors and N groups of current harmonic phasors can be obtained. In this embodiment, the nth group of voltage harmonic phasors are denoted as

Denote the nth group of current harmonic phasors as

where n=1,2...N. k represents the three phases of A, B, and C in the distribution network, and h represents the harmonic order, which can be 3, 5, 7, ... etc. understandably,

and

Both are discrete time series with respect to time t. The form of its amplitude and phase angle can be expressed as

and

Step S108: Obtain the zero-crossing time of the rising edge of the fundamental wave voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase at the zero-crossing time as a reference, according to the harmonic phase of the current signal of each phase. Obtain the phase of each harmonic of each phase current signal at the zero-crossing point of each phase.

The fundamental wave is the 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 the fundamental wave of each phase is the moment when the phase angle of the fundamental wave voltage of each phase is 0. For example, when the phase angle of the fundamental wave voltage of each phase is 0, it can be expressed as

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

At each current moment, it is judged whether the phase angle of the fundamental wave voltage of each phase meets the following conditions: the phase angle of the fundamental wave voltage at the previous moment is less than zero, and the phase angle of the fundamental wave voltage at the next moment is greater than zero; if so, the current moment is zero o'clock time.

Taking phase A as an example, the formula is expressed as:

t ₀ -1:

t ₀ +1:

After finding the zero-crossing time t ₀ of the rising edge of the fundamental wave voltage of each phase, find each h-order harmonic phase of the same phase of the harmonic phasors of the same group of current signals, and the h-order harmonic phase is the one required by the application. harmonic phase.

获取A相基波电压相角

的时刻t₀后，找到A相h次谐波电流

中时刻t₀对应的相位

即为第n组相量数组中A相h次谐波电流以A相基波电压上升沿的过零点为参考的相位。That is: through

Get A-phase fundamental voltage phase angle

After the time t ₀ of , find the h-th harmonic current of phase A

The phase corresponding to the middle time t ₀

That is, the phase of the h-th harmonic current of phase A in the nth group of phasor arrays with the zero-crossing point of the rising edge of the fundamental voltage of phase A as the reference.

在其中一个实施例中，所述各次谐波为3次谐波、5次谐波以及7次谐波。Repeat the above steps for B-phase and C-phase to obtain the phase of the h-th harmonic current of B and C phases in the nth group of phasor arrays

In one of the embodiments, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

Step S110: Perform analysis based on all phase data obtained within the statistical time.

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 power quality. In one embodiment, the method of analyzing the harmonic phase is to plot the harmonic current phase distribution. For example, for the 3rd harmonic current, the phase data of the 3rd harmonic current obtained in each calculation window will be represented in the phase distribution diagram; for the 5th harmonic current, the 5th harmonic current obtained in each calculation window will be Harmonic current phase data is represented in a phase profile; and so on.

For a better explanation, the following is a detailed description of the residential electricity load of a public substation as an example:

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

以及每相电力用户馈线的3次、5次、7次谐波电流相量

其中k＝A,B,C以及h＝3,5,7。(2) The total statistical time is 12 hours, and the fast Fourier transform (FFT) calculation interval is 5 seconds, then N is 8640 in the statistical time, that is, a total of 8640 groups of voltage waveform signals and each phase current waveform signal are collected. In each group of voltage waveform signals and each phase current waveform signal, 10 cycles are intercepted from the collected A-phase voltage waveform signal u _A (t) and each phase current waveform signal i _k (t), respectively, using fast Fourier transform Transform (FFT) to transform. The obtained A-phase fundamental voltage phasor on the public transformer bus

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.

的时刻t₀作为A相基波电压上升沿的过零点，并以此为参考基准。(3) For the nth phasor array, find the phase angle of the fundamental voltage of phase A

The time t ₀ is taken as the zero-crossing point of the rising edge of the fundamental voltage of phase A, and takes this as the reference.

中时刻t₀对应的

即为第n组相量数组中A相h次谐波电流以A相基波电压上升沿的过零点为参考的相位。(4) Set k=A, in the nth phasor array, find the h-th harmonic current of phase A

Corresponding to the middle time t ₀

That is, the phase of the h-th harmonic current of phase A in the nth group of phasor arrays with the zero-crossing point of the rising edge of the fundamental voltage of phase A as the reference.

(5) Set k=B and k=C respectively, and repeat step (4) to obtain the phase of the h-th harmonic current of B and C phases in the nth array

(6) Repeat steps (3), (4), (5) until n=8640. According to the obtained results, the phase distribution diagrams of the 3rd, 5th, and 7th harmonic currents obtained based on the zero-crossing point of the A-phase fundamental wave voltage are made. As shown in Figure 2a ~ Figure 2c.

Based on the same inventive concept, a power grid harmonic phase analysis system is also provided. As shown in FIG. 3 , a power grid harmonic phase analysis system 300 according to an embodiment includes:

The signal acquisition module 302 is configured to acquire the voltage waveform signal of the bus of interest and the current waveform signal of the power user feeder.

Among them, the busbar of interest is the busbar whose harmonic phase characteristics are to be analyzed, and the power user feeder is the distribution line allocated from the busbar of interest, and is connected to the load on the user side.

Specifically, the voltage waveform signal and the current waveform signal can be obtained by using a potential transformer (PT) and a current transformer (CT) in conjunction with a data acquisition and supervisory control system (Supervisory Control And Data Acquisition System, SCADA). .

SCADA is a data acquisition, monitoring and control system for the production system with long distribution distance and scattered production units. SCADA occupies an important position in the telecontrol system, which can monitor and control the running equipment in the field to realize various functions such as data acquisition, equipment control, measurement, parameter adjustment and various signal alarms. An important part of SCADA includes remote terminal unit (Remote Terminal Unit, RTU), and feeder terminal unit (Feedback Terminal Unit, FTU).

Voltage transformers and current transformers are voltage and current measuring instruments made using the principle of mutual inductance. In order 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 signal of the concerned bus and the three-phase current waveform signal on the power user feeder are collected, and the sampling frequency of each phase of the voltage waveform signal and the current waveform signal is not less than 12.8 kHz.

In this embodiment, the voltage waveform signal is denoted as _uk (t), and the current signal waveform is denoted as _ik (t). Where k represents the three phases of A, B, and C in the distribution network, and t represents time.

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

In order to analyze the harmonic phase characteristics, it is necessary to collect the signal waveform for analysis and calculation in a long statistical time. In one of the embodiments, the calculation window is divided equally into a fixed duration within the statistical time. That is, one interception and calculation is performed according to a fixed duration. For example, the statistical time is 12 hours. If the interception and calculation are performed every 5 seconds, 8640 interceptions and calculations are required.

The calculation window is the calculation time period. In this step, a preset number of cycles are intercepted from the voltage waveform signal and the current waveform signal during at least one calculation period. A cycle is the waveform of one signal period. For example, for the power frequency voltage, if the voltage frequency is 50Hz, one signal period is 0.02 seconds. The preset number is determined according to the situation, for example, the number of intercepted cycles is determined according to the calculation capability, calculation accuracy requirements, and the like. In one of the embodiments, 10 cycles, ie, waveform signals with a duration of 200 milliseconds, may be intercepted from the voltage waveform signal and the current waveform signal, respectively.

The harmonic phasor calculation module 306 is configured 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.

Taking 10 cycles as an example, in each calculation window, fast Fourier transform (Fast Fourier Transform, FFT) will be performed on the 10 cycle signals. A set of voltage harmonic phasors and a set of current harmonic phasors can be obtained respectively.

将第n组电流谐波相量记为

其中n＝1,2……N。k代表配电网中的A、B、C三相，h代表谐波次数，可以是3、5、7、……等。可以理解，

和

都是关于时间t的离散时间序列。其幅值相角的形式分别可表示为

和

In the statistical time, a set of voltage harmonic phasors and a set of current harmonic phasors can be obtained for each calculation. Therefore, N groups of voltage harmonic phasors and N groups of current harmonic phasors can be obtained in total. In this embodiment, the nth group of voltage harmonic phasors are denoted as

Denote the nth group of current harmonic phasors as

where n=1,2...N. k represents the three phases of A, B, and C in the distribution network, and h represents the harmonic order, which can be 3, 5, 7, ... etc. understandably,

and

are all discrete time series with respect to time t. The form of its amplitude and phase angle can be expressed as

and

The harmonic phase calculation module 308 is configured to obtain the zero-crossing point moment of the rising edge of the fundamental wave voltage of each phase according to the harmonic phasor of the voltage signal of each phase, and use the phase of the zero-crossing point as a reference. The harmonic phasor of the current signal obtains the phase of each harmonic of each phase current signal at the zero-crossing point of each phase.

The fundamental wave is the 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 the fundamental wave of each phase is the moment when the phase angle of the fundamental wave voltage of each phase is 0. For example, when the phase angle of the fundamental wave voltage of each phase is 0, it can be expressed as

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

At each current moment, it is judged whether the phase angle of the fundamental wave voltage of each phase meets the following conditions: the phase angle of the fundamental wave voltage at the previous moment is less than zero, and the phase angle of the fundamental wave voltage at the next moment is greater than zero; if so, the current moment is zero o'clock time.

Taking phase A as an example, the formula is expressed as:

t ₀ -1:

t ₀ +1:

After finding the zero-crossing time t ₀ of the rising edge of the fundamental wave voltage of each phase, find each h-order harmonic phase of the same phase of the harmonic phasors of the same group of current signals, and the h-order harmonic phase is the one required by the application. harmonic phase.

获取A相基波电压相角

的时刻t₀后，找到A相h次谐波电流

中时刻t₀对应的相位

即为第n组相量数组中A相h次谐波电流以A相基波电压上升沿的过零点为参考的相位。That is: through

Get A-phase fundamental voltage phase angle

After the time t ₀ of , find the h-th harmonic current of phase A

The phase corresponding to the middle time t ₀

That is, the phase of the h-th harmonic current of phase A in the nth group of phasor arrays with the zero-crossing point of the rising edge of the fundamental voltage of phase A as the reference.

在其中一个实施例中，所述各次谐波为3次谐波、5次谐波以及7次谐波。Repeat the above steps for B-phase and C-phase to obtain the phase of the h-th harmonic current of B and C phases in the nth group of phasor arrays

In one of the embodiments, the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic.

An analysis module 310 for performing analysis based on all phase data obtained within the statistical time.

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 power quality. In one embodiment, the method of analyzing the harmonic phase is to plot the harmonic current phase distribution. For example, for the 3rd harmonic current, the phase data of the 3rd harmonic current obtained in each calculation window will be represented in the phase distribution diagram; for the 5th harmonic current, the 5th harmonic current obtained in each calculation window will be Harmonic current phase data is represented in a phase profile; and so on.

Based on the same inventive concept, a power grid harmonic phase analysis device is also provided. The power grid harmonic phase analysis device includes 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.

The above power grid harmonic phase analysis method, system and device can more accurately reflect the harmonic current phase distribution by taking the zero-crossing point of the rising edge of the fundamental wave voltage as a reference to obtain the phase of each phase and each harmonic. The harmonic current phase of each phase is obtained corresponding to the fundamental wave voltage of each phase. For example, according to the zero-crossing point of the rising edge of phase A of the fundamental wave voltage, the phase of each harmonic current of phase A of the harmonic current is obtained, which will not be determined because of the phase sequence. It is affected by the error, so it has the capability of phase sequence fault tolerance.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a power grid harmonic phase analysis method, is characterized in that, described method comprises: Obtain the voltage waveform signal of the concerned bus and the current waveform signal of the power user feeder; dividing the statistical time into a plurality of calculation windows; and in each calculation window, intercepting a preset number of cycles from the voltage waveform signal and the current waveform signal; 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; Obtain 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, and take the phase at the zero-crossing time as a reference, and obtain each phase according to the harmonic phasor of the current signal of each phase. The phase of each harmonic of the phase current signal at the zero-crossing time of each phase; Analysis is based on all phase data acquired within statistical time. 2 . The power grid harmonic phase analysis method according to claim 1 , wherein the calculation window is divided into equal parts by a fixed duration in the statistical time. 3 . 3. The power grid harmonic phase analysis method according to claim 1, wherein the acquiring the voltage waveform signal of the concerned bus and the current waveform signal on the power user feeder comprises: The voltage waveform signal and the current waveform signal are obtained by using the voltage transformer and the current transformer in cooperation with the data acquisition and monitoring control system. 4 . The power grid harmonic phase analysis method according to claim 1 , wherein the sampling frequency of each channel of the voltage waveform signal and the current waveform signal is not less than 12.8 kHz. 5 . 5 . The power grid harmonic phase analysis method according to claim 1 , wherein the preset number is 10. 6 . 6 . The power grid harmonic phase analysis method according to claim 1 , wherein, 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, comprising: 6 . At each current moment, it is judged whether the phase angle of the fundamental wave voltage of each phase meets the following conditions: the phase angle of the fundamental wave voltage at the previous moment is less than zero, and the phase angle of the fundamental wave voltage at the next moment is greater than zero; If satisfied, the current time is the zero-crossing time. 7 . The power grid harmonic phase analysis method according to claim 2 , wherein the fixed duration is 5 seconds. 8 . 8 . The power grid harmonic phase analysis method according to claim 1 , wherein the harmonics are the 3rd harmonic, the 5th harmonic and the 7th harmonic. 9 . 9. A power grid harmonic phase analysis system, comprising: The signal acquisition module is used to acquire the voltage waveform signal of the concerned bus and the current waveform signal of the power user feeder; a waveform interception module, configured to divide the statistical time into a plurality of calculation windows; and in each calculation window, intercept a preset number of cycles from the voltage waveform signal and the current waveform signal; a harmonic phasor calculation module, configured 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; 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, according to the current of each phase The harmonic phasor of the signal obtains the phase of each harmonic of each phase current signal at the zero-crossing time of each phase; Analysis module for analysis based on all phase data acquired in statistical time. 10. A power grid harmonic phase analysis device, characterized in that it comprises a memory and a processor, wherein the memory stores a computer program, characterized in that, when the processor executes the computer program, the implementation of claims 1 to 8 The steps of any one of the methods.

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