阅读说明：本技术 一种包含逆变器的分布式电源谐波检测方法 (Distributed power supply harmonic detection method comprising inverter ) 是由 毛艳芳 于 2021-08-23 设计创作，主要内容包括：本发明提供了一种包含逆变器的分布式电源谐波检测方法,包括：(1)：采集电流信号、电压信号；(2)：计算分布式电源功率因数；(3)：判断功率因数是否大于参考值,若是,进入(4)；若不是,返回(1)；(4)：对电压信号进行转换,列出离散时间函数；(5)：构建自相关函数；(6)：构建自相关矩阵；(7)：计算自相关矩阵特征值矩阵；(8)：计算自相关矩阵对应空间向量矩阵；(9)：计算信号源数目；(10)：计算功率谱分析曲线；(11)：判断是否异常,并及时报警显示。本发明提供一种包含逆变器的分布式电源谐波检测方法,能够准确计算出实际的谐波频率和谐波功率,进而更好的进行谐波判断。(The invention provides a distributed power supply harmonic detection method comprising an inverter, which comprises the following steps: (1): collecting current signals and voltage signals; (2): calculating a distributed power supply power factor; (3): judging whether the power factor is larger than a reference value, if so, entering (4); if not, returning to the step (1); (4): converting the voltage signal and listing a discrete time function; (5): constructing an autocorrelation function; (6): constructing an autocorrelation matrix; (7): calculating an autocorrelation matrix eigenvalue matrix; (8): calculating a space vector matrix corresponding to the autocorrelation matrix; (9): calculating the number of signal sources; (10): calculating a power spectrum analysis curve; (11): and judging whether the abnormal condition exists or not, and timely alarming and displaying. The invention provides a distributed power supply harmonic detection method comprising an inverter, which can accurately calculate the actual harmonic frequency and the actual harmonic power so as to better judge the harmonic.)

1. A distributed power harmonic detection method comprising an inverter, the distributed power harmonic detection method comprising the steps of:

step (1): collecting current signals and voltage signals;

step (2): calculating the distributed power supply power factor;

and (3): judging whether the power factor is larger than a power factor reference value or not, if so, entering a step (4); if not, returning to the step (1);

and (4): converting the voltage signal to list a discrete time function;

and (5): constructing an autocorrelation function;

and (6): constructing an autocorrelation matrix according to the autocorrelation function;

and (7): calculating an eigenvalue matrix of the autocorrelation matrix;

and (8): calculating a space vector matrix corresponding to the autocorrelation matrix;

and (9): calculating the number of signal sources;

step (10): calculating a power spectrum analysis curve to obtain harmonic frequency and harmonic power;

step (11): and judging whether the harmonic frequency and the harmonic power are abnormal or not, and timely alarming and displaying.

2. The method of claim 1, wherein the algorithm for calculating the discrete time function of the voltage signal isWherein N is the highest harmonic order, k is the harmonic order, u_kIs the amplitude of the k harmonic wave, f_kFor the k-th harmonic frequency, Δ t is the sampling interval, v (I) is white noise, I is 0,1, …, I-1, I is the number of sample points.

3. The method of claim 2, wherein the algorithm for calculating the autocorrelation function is

4. The method of claim 3, wherein the algorithm for constructing the autocorrelation matrix isFrom (m +1) r_u(l) And (4) forming.

5. The inverter-containing distributed power harmonic detection method according to claim 4, wherein an algorithm for calculating the space vector matrix corresponding to the autocorrelation matrix is R' ═ RE_kWherein, in the step (A),

6. the method of claim 5, wherein the algorithm for calculating the number of signal sources isWherein A is the number of the characteristic values, andthe above-mentionedSaid lambda_iIs the ith characteristic value; the J is the number of signal sources.

7. The method of claim 6, wherein the algorithm for calculating the power spectrum analysis curve isWherein the content of the first and second substances,said E_NForming a matrix by the other rows of the space vector matrix except B, wherein B is the first row of the space vector matrix;

when the power spectrum analysis curve has a peak, the corresponding frequency is the harmonic frequency, and the corresponding power is the harmonic power.

Technical Field

The invention belongs to the technical field of power detection, and particularly relates to a distributed power supply harmonic detection method comprising an inverter.

Background

With the consumption of traditional energy and environmental problems, distributed power sources are widely used by people, and the electric energy of the distributed power sources needs to be converted into alternating current which meets the requirements through an inverter and then is output. Due to different types of loads, a certain harmonic component may flow in, which may cause unstable operation of the distributed power supply, and further affect power consumers and even the power grid.

In order to ensure the safety and reliability of the power utilization users and the safety of the operation of the power grid, the harmonic waves need to be controlled within a safety range, and the generation and expansion of harmonic wave hazards are avoided.

At present, harmonic detection is easily affected by the environment, and meanwhile, specific harmonic frequency and energy cannot be accurately found, so that the detection result cannot be accurate, and better processing cannot be performed. The invention provides a distributed power supply harmonic detection method comprising an inverter, which can accurately calculate the actual harmonic frequency and the actual harmonic power so as to better judge the harmonic.

Disclosure of Invention

The invention provides a distributed power supply harmonic detection method comprising an inverter, which can accurately calculate the actual harmonic frequency and the actual harmonic power so as to better judge the harmonic.

The invention specifically relates to a distributed power supply harmonic detection method comprising an inverter, which comprises the following steps:

step (1): collecting current signals and voltage signals;

step (2): calculating the distributed power supply power factor;

and (3): judging whether the power factor is larger than a power factor reference value or not, if so, entering a step (4); if not, returning to the step (1);

and (4): converting the voltage signal to list a discrete time function;

and (5): constructing an autocorrelation function;

and (6): constructing an autocorrelation matrix according to the autocorrelation function;

and (7): calculating an eigenvalue matrix of the autocorrelation matrix;

and (8): calculating a space vector matrix corresponding to the autocorrelation matrix;

and (9): calculating the number of signal sources;

step (10): calculating a power spectrum analysis curve to obtain harmonic frequency and harmonic power;

step (11): and judging whether the harmonic frequency and the harmonic power are abnormal or not, and timely alarming and displaying.

The algorithm for calculating the discrete time function of the voltage signal is

Wherein N is the highest harmonic order, k is the harmonic order, u_kIs the amplitude of the k harmonic wave, f_kFor the k-th harmonic frequency, Δ t is the sampling interval, v (I) is white noise, I is 0,1, …, I-1, I is the number of sample points.

The algorithm for calculating the autocorrelation function is

The algorithm for constructing the autocorrelation matrix is

From (m +1) r_u(l) And (4) forming.

The algorithm for calculating the space vector matrix corresponding to the autocorrelation matrix is

R′＝RE_kWherein, in the step (A),

the algorithm for calculating the number of the signal sources is

Wherein A is the number of the characteristic values, andthe above-mentionedSaid lambda_iIs the ith characteristic value; the J is the number of signal sources.

The algorithm for calculating the power spectrum analysis curve is

Wherein the content of the first and second substances,said E_NForming a matrix by the other rows of the space vector matrix except B, wherein B is the first row of the space vector matrix;

when the power spectrum analysis curve has a peak, the corresponding frequency is the harmonic frequency, and the corresponding power is the harmonic power.

Compared with the prior art, the beneficial effects are: the distributed power supply harmonic detection method can accurately calculate the actual harmonic frequency and the actual harmonic power, and further can better judge the harmonic.

Drawings

Fig. 1 is a flowchart illustrating a method for detecting harmonics in a distributed power supply including an inverter according to the present invention.

Detailed Description

The following describes in detail a specific embodiment of a distributed power harmonic detection method including an inverter according to the present invention with reference to the accompanying drawings.

As shown in fig. 1, the distributed power harmonic detection method of the present invention includes the following steps:

step (1): collecting current signals and voltage signals;

step (2): calculating the distributed power supply power factor;

and (3): judging whether the power factor is larger than a power factor reference value or not, if so, entering a step (4); if not, returning to the step (1);

and (4): converting said voltage signal to list a discrete time functionWherein N is the highest harmonic order, k is the harmonic order, u_kIs the amplitude of the k harmonic wave, f_kK harmonic frequency, delta t sampling time interval, v (I) white noise, I is 0,1, …, I-1, I is the number of sampling points;

and (5): constructing autocorrelation functions

And (6): constructing an autocorrelation matrix from the autocorrelation functionFrom (m +1) r_u(l) Composition is carried out;

and (7): calculating an eigenvalue matrix of the autocorrelation matrix;

and (8): calculating a space vector matrix R' ═ RE corresponding to the autocorrelation matrix_kWherein, in the step (A),

and (9): calculating the number of signal sourcesWherein A is the number of the characteristic values, andthe above-mentionedSaid lambda_iIs the ith characteristic value; the J is the number of the signal sources;

step (10): calculating a power spectral analysis curveWherein the content of the first and second substances,said E_NForming a matrix by the other rows of the space vector matrix except B, wherein B is the first row of the space vector matrix; calculating harmonic frequency and harmonic power;

step (11): judging whether the harmonic frequency and the harmonic power are abnormal or not, and timely alarming and displaying:

comparing the harmonic frequency with a harmonic frequency reference value, and if the harmonic frequency is greater than the harmonic frequency reference value, sending out a harmonic frequency abnormity alarm;

and comparing the harmonic power with a harmonic power reference value, and if the harmonic power is greater than the harmonic power reference value, sending out a harmonic power abnormity alarm.

When the power spectrum analysis curve has a peak, the corresponding frequency is the harmonic frequency, and the corresponding power is the harmonic power.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.