阅读说明：本技术 一种计量装置互感器二次回路信号频率测量方法及系统 (Method and system for measuring signal frequency of secondary circuit of mutual inductor of metering device ) 是由 王海元 谭海波 李恺 解玉满 卜文彬 黄红桥 谈丛 郭光� 李鑫 陈浩 刘谋海 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种计量装置互感器二次回路信号频率测量方法及系统,包括针对采样的计量装置互感器二次回路信号中长度为N的连续采样点的采样信号x(n)采用II型线性相位无限冲击响应滤波器进行滤波得到滤波后的采样信号s(n)；采用中心频率与带宽均为50Hz的带通滤波器分别对滤波后的采样信号s(n)、x(n)进行滤波校正得到第一校正信号A-s(n)、第二校正信号A-y(n)并计算增益值G(ω)；基于增益值G(ω)计算出电网的基波频率f。本发明克服了传统频率测量方法的问题,采用II型线性相位无限冲击响应滤波器的测量方式计算简单,能够快速估计出精确电网频率,为电能准确计量提供了一条有效的途径。(The invention discloses a method and a system for measuring the frequency of a secondary circuit signal of a mutual inductor of a metering device, which comprises the steps of filtering a sampling signal x (N) of a continuous sampling point with the length of N in a sampled secondary circuit signal of the mutual inductor of the metering device by adopting a II-type linear phase infinite impulse response filter to obtain a filtered sampling signal s (N); respectively filtering and correcting the filtered sampling signals s (n), x (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A s (n) second correction signal A y (n) and calculating a gain value G (ω); and calculating the fundamental frequency f of the power grid based on the gain value G (omega). The invention overcomes the problems of the traditional frequency measurement method, adopts the measurement mode of the II-type linear phase infinite impulse response filter to calculate simply, can quickly estimate the accurate grid frequency and provides an effective way for accurately measuring the electric energy.)

1. A method for measuring the signal frequency of a secondary circuit of a mutual inductor of a metering device is characterized by comprising the following steps:

1) aiming at a sampling signal x (N) of continuous sampling points with the length of N in a secondary circuit signal of a mutual inductor of the metering device obtained by sampling, a II-type linear phase infinite impulse response filter h is adopted_ip(n) filtering to obtain a filtered sampling signal s (n);

2) respectively filtering and correcting the filtered sampling signals s (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A_s(n), filtering and correcting the sampling signal x (n) to obtain a second correction signal A_y(n)；

3) From the second correction signal A_y(n) first correction signal A_s(n) calculating a gain value G (omega) of the type II linear phase infinite impulse response filter;

4) and calculating the fundamental frequency f of the power grid based on the gain value G (omega).

2. The method for measuring the secondary loop signal frequency of the mutual inductor of the metering device according to claim 1, wherein the length N in the step 1) is an integer power of 2.

3. The method for measuring the signal frequency of the secondary circuit of the mutual inductor of the metering device according to claim 1, wherein the type II linear phase infinite impulse response filter h in the step 1)_ipAnd (n) designing a II type linear phase infinite impulse response filter by adopting a 4-order triangular convolution window function.

4. The method for measuring the frequency of the secondary loop signal of the mutual inductor of the metering device according to claim 3, wherein the II-type linear phase infinite impulse response filter h_ipThe functional expression of (n) is:

h_ip(n)＝w_0.25(n)*w_0.25(n)*w_0.25(n)*w_0.25(n)

in the above formula, w_0.25(N) represents a triangular window function of length N/4, representing a convolution operation.

5. The method for measuring the frequency of the secondary loop signal of the mutual inductor of the metering device according to claim 4, wherein the II-type linear phase infinite impulse response filter h_ipThe functional expression for the frequency response of (n) is:

H_ip(e^jω)＝＝(W_t(e^jω))⁴

in the above formula, H_ip(e^jω) Filter h representing type II linear phase infinite impulse response_ipFrequency response of (n), W_t(e^jω) The spectrum of a triangular window function of length N/4 is represented.

6. The method for measuring the secondary loop signal frequency of the mutual inductor of the metering device according to claim 1, wherein in the step 2), a band-pass filter with the center frequency and the bandwidth both being 50Hz is adopted to filter and correct the filtered sampling signal s (n) to obtain a first correction signal A_sThe functional expression of (n) is:

A_s(n)＝RA{s(n)}

wherein RA represents the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz;

filtering and correcting the sampling signal x (n) by adopting a band-pass filter with the center frequency and the bandwidth both being 50Hz to obtain a second correction signal A_yThe functional expression of (n) is:

A_y(n)＝RA{x(n)}

where RA denotes the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz.

7. The method for measuring the signal frequency of the secondary loop of the mutual inductor of the metering device according to claim 1, wherein the functional expression for calculating the gain value G (ω) of the infinite impulse response filter of the type II linear phase in the step 3) is as follows:

G(ω)＝A_y(n)/A_s(n)

in the above formula, A_y(n) is a second correction signal, A_sAnd (n) is a first correction signal.

8. The method for measuring the secondary loop signal frequency of the mutual inductor of the metering device according to claim 1, wherein the step 4) comprises the following steps: taking a gain value G (omega) as the amplitude-frequency response of the II type linear phase infinite impulse response filter, firstly, according to the inverse function of the gain value G (omega)Calculating to obtain angular frequency omega (n); then according to f ═ ω f_sCalculating fundamental frequency f of the power grid (4 pi), wherein omega is the average value of angular frequency omega (n), f_sIs the sampling frequency.

9. A measuring system of secondary loop signal frequency of a mutual inductor of a metering device, comprising a microprocessor and a memory which are connected with each other, characterized in that the microprocessor is programmed or configured to execute the steps of the measuring method of secondary loop signal frequency of mutual inductor of a metering device according to any one of claims 1 to 8, or the memory is stored with a computer program which is programmed or configured to execute the measuring method of secondary loop signal frequency of mutual inductor of a metering device according to any one of claims 1 to 8.

10. A computer readable storage medium having stored thereon a computer program programmed or configured to perform a method of measuring a frequency of a secondary loop signal of a transducer of a metering device according to any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of power grid frequency measurement, and particularly relates to a method and a system for measuring the secondary loop signal frequency of a mutual inductor of a metering device.

Background

Accurate measurement of frequency is the basis for electrical energy metering. The mutual inductor and the secondary circuit in the electric energy metering device are important factors causing metering error change, and new requirements are provided for the real-time performance of frequency measurement so as to ensure the safe and stable operation of the system and the accurate metering of the electric energy. However, frequency measurement based on full-period sampling or fourier transform methods often has problems. For example, when the number of samples is small, the measurement error is large, and increasing the number of samples leads to poor real-time performance, which is difficult to meet the requirement of accurate measurement of electric energy. Therefore, how to improve the accuracy of the grid frequency has become a key technical problem to be solved urgently.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problems in the prior art, the invention provides a method and a system for measuring the secondary circuit signal frequency of a mutual inductor of a metering device, which overcome the problems of the traditional frequency measuring method, have simple calculation by adopting a measuring mode of a II-type linear phase infinite impulse response filter, can quickly estimate the accurate power grid frequency, provide an effective way for accurately measuring electric energy, and overcome the defects of large calculation amount and poor real-time property of the traditional frequency measuring method.

In order to solve the technical problems, the invention adopts the technical scheme that:

a method for measuring the signal frequency of a secondary circuit of a mutual inductor of a metering device comprises the following steps:

1) aiming at a sampling signal x (N) of continuous sampling points with the length of N in a secondary circuit signal of a mutual inductor of the metering device obtained by sampling, a II-type linear phase infinite impulse response filter h is adopted_ip(n) filtering to obtain a filtered sampling signal s (n);

2) respectively filtering and correcting the filtered sampling signals s (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A_s(n), filtering and correcting the sampling signal x (n) to obtain a second correction signal A_y(n)；

3) From the second correction signal A_y(n) first correction signal A_s(n) calculating a gain value G (omega) of the type II linear phase infinite impulse response filter;

4) and calculating the fundamental frequency f of the power grid based on the gain value G (omega).

Optionally, the length N in step 1) is an integer power of 2.

Optionally, the type II linear phase infinite impulse response filter h in step 1)_ipAnd (n) designing a II type linear phase infinite impulse response filter by adopting a 4-order triangular convolution window function.

Optionally, the type II linear phase infinite impulse response filter h_ipThe functional expression of (n) is:

h_ip(n)＝w_0.25(n)*w_0.25(n)*w_0.25(n)*w_0.25(n)

in the above formula, w_0.25(N) represents a triangular window function of length N/4, representing a convolution operation.

Optionally, the type II linear phase infinite impulse response filter h_ipThe functional expression for the frequency response of (n) is:

H_ip(e^jω)＝＝(W_t(e^jω))⁴

in the above formula, H_ip(e^jω) Filter h representing type II linear phase infinite impulse response_ipFrequency response of (n), W_t(e^{j ω}) The spectrum of a triangular window function of length N/4 is represented.

Optionally, in step 2), a band-pass filter with a center frequency and a bandwidth of 50Hz is used to perform filtering correction on the filtered sampling signal s (n) to obtain a first correction signal a_sThe functional expression of (n) is:

A_s(n)＝RA{s(n)}

wherein RA represents the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz;

filtering and correcting the sampling signal x (n) by adopting a band-pass filter with the center frequency and the bandwidth both being 50Hz to obtain a second correction signal A_yThe functional expression of (n) is:

A_y(n)＝RA{x(n)}

where RA denotes the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz.

Optionally, the functional expression for calculating the gain value G (ω) of the type II linear-phase infinite impulse response filter in step 3) is:

G(ω)＝A_y(n)/A_s(n)

in the above formula, A_y(n) is a second correction signal, A_sAnd (n) is a first correction signal.

Optionally, step 4) comprises: taking a gain value G (omega) as the infinite impulse response of the type II linear phaseThe amplitude-frequency response of the filter is first determined by the inverse function of the gain value G (omega)Calculating to obtain angular frequency omega (n); then according to f ═ ω f_sCalculating fundamental frequency f of the power grid (4 pi), wherein omega is the average value of angular frequency omega (n), f_sIs the sampling frequency.

In addition, the invention also provides a metering device transformer secondary circuit signal frequency measurement system, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the steps of the metering device transformer secondary circuit signal frequency measurement method, or the memory is stored with a computer program which is programmed or configured to execute the metering device transformer secondary circuit signal frequency measurement method.

Furthermore, the invention also provides a computer readable storage medium, in which a computer program programmed or configured to execute the method for measuring the secondary loop signal frequency of a transformer of a metering device is stored.

Compared with the prior art, the invention has the following advantages: the method comprises the steps that sampling signals x (N) of continuous sampling points with the length of N in secondary circuit signals of a mutual inductor of a sampling metering device are filtered by a II-type linear phase infinite impulse response filter to obtain filtered sampling signals s (N); respectively filtering and correcting the filtered sampling signals s (n), x (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A_s(n) second correction signal A_y(n) and calculating a gain value G (ω); the fundamental frequency f of the power grid is calculated based on the gain value G (omega), through the method, the problem of the traditional frequency measurement method is solved, the measurement mode of the II-type linear phase infinite impulse response filter is simple to calculate, the accurate power grid frequency can be quickly estimated, an effective way is provided for accurate electric energy measurement, and the defects of large calculation amount and poor real-time performance of the traditional frequency measurement method are overcome.

Drawings

FIG. 1 is a basic flow diagram of a method according to an embodiment of the present invention.

Detailed Description

As shown in fig. 1, the method for measuring the frequency of the secondary loop signal of the mutual inductor of the metering device in the embodiment includes:

1) aiming at a sampling signal x (N) of continuous sampling points with the length of N in a secondary circuit signal of a mutual inductor of the metering device obtained by sampling, a II-type linear phase infinite impulse response filter h is adopted_ip(n) filtering to obtain a filtered sampling signal s (n);

2) respectively filtering and correcting the filtered sampling signals s (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A_s(n), filtering and correcting the sampling signal x (n) to obtain a second correction signal A_y(n)；

3) From the second correction signal A_y(n) first correction signal A_s(n) calculating a gain value G (omega) of the type II linear phase infinite impulse response filter;

4) and calculating the fundamental frequency f of the power grid based on the gain value G (omega).

In this embodiment, the secondary loop signal of the mutual inductor of the metering device is acquired by a Zhongtai wound EM-9106B acquisition card with a sampling frequency f_sSetting the frequency to 1600Hz, and converting the data into 16 bits; the data analysis adopts a Daire achievement 3681 commercial office high-performance desktop, and adopts C + + language to write a calculation program to complete frequency measurement. The length N in step 1) is an integer power of 2, and in this embodiment, the length N is 1024.

In this embodiment, the type II linear phase infinite impulse response filter h in step 1)_ipAnd (n) designing a II type linear phase infinite impulse response filter by adopting a 4-order triangular convolution window function.

In this embodiment, the II-type linear phase infinite impulse response filter h_ipThe functional expression of (n) is:

h_ip(n)＝w_0.25(n)*w_0.25(n)*w_0.25(n)*w_0.25(n)

in the above formula, the first and second carbon atoms are,w_0.25(N) represents a triangular window function of length N/4, representing a convolution operation. In this embodiment, the length N is 1024, so the length of the triangular window function is 256.

In this embodiment, the II-type linear phase infinite impulse response filter h_ipThe functional expression for the frequency response of (n) is:

H_ip(e^jω)＝＝(W_t(e^jω))⁴

in the above formula, H_ip(e^jω) Filter h representing type II linear phase infinite impulse response_ipFrequency response of (n), W_t(e^{j ω}) The spectrum of a triangular window function of length N/4 is represented.

In this embodiment, in step 2), a band-pass filter with a center frequency and a bandwidth of 50Hz is used to perform filtering correction on the filtered sampling signal s (n) to obtain a first correction signal a_sThe functional expression of (n) is:

A_s(n)＝RA{s(n)}

wherein RA represents the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz;

filtering and correcting the sampling signal x (n) by adopting a band-pass filter with the center frequency and the bandwidth both being 50Hz to obtain a second correction signal A_yThe functional expression of (n) is:

A_y(n)＝RA{x(n)}

where RA denotes the filtering operation of a band-pass filter with a center frequency and a bandwidth of 50 Hz.

In this embodiment, the length of the bandpass filter whose center frequency and bandwidth are both 50Hz is 1024.

In this embodiment, the functional expression for calculating the gain value G (ω) of the type II linear phase infinite impulse response filter in step 3) is:

G(ω)＝A_y(n)/A_s(n)

in the above formula, A_y(n) is a second correction signal, A_sAnd (n) is a first correction signal.

In this embodiment, step 4) includes: the gain value G (omega)) As the amplitude-frequency response of the II-type linear phase infinite impulse response filter, firstly, the amplitude-frequency response is determined according to the inverse function of the gain value G (omega)Calculating to obtain angular frequency omega (n); then according to f ═ ω f_sCalculating fundamental frequency f of the power grid (4 pi), wherein omega is the average value of angular frequency omega (n), f_sIs the sampling frequency. For example, in this embodiment, the sequence of angular frequencies ω (n) calculated from the inverse function of the gain value G (ω) is:

[0.6442,0.6439,0.6250,0.5827,0.4321,0.3728,0.3668,0.6425,0.6776,0.6816,0.3662,0.3665,0.3656,0.3720,……,0.3660,0.6250,0.6442,0.5848,0.6439,0.5827,0.4271]

the average value of the angular frequency ω (n) was calculated to be 0.3893. Thus, there are:

in summary, the method for measuring the secondary loop signal frequency of the metering device transformer in this embodiment includes filtering a sampling signal x (N) of a sampling point with a length of N in a secondary loop signal of the metering device transformer by using a type II linear phase infinite impulse response filter to obtain a filtered sampling signal s (N); respectively filtering and correcting the filtered sampling signals s (n), x (n) by adopting a band-pass filter with the center frequency and the bandwidth of 50Hz to obtain a first correction signal A_s(n) second correction signal A_y(n) and calculating a gain value G (ω); and calculating the fundamental frequency f of the power grid based on the gain value G (omega). The invention overcomes the problems of the traditional frequency measurement method, adopts the measurement mode of the II-type linear phase infinite impulse response filter to calculate simply, can quickly estimate the accurate grid frequency and provides an effective way for accurately measuring the electric energy.

In addition, the present embodiment also provides a measuring system for measuring a secondary loop signal frequency of a transformer of a metering device, which includes a microprocessor and a memory, which are connected to each other, wherein the microprocessor is programmed or configured to execute the steps of the measuring method for measuring a secondary loop signal frequency of a transformer of a metering device, or the memory stores a computer program programmed or configured to execute the measuring method for measuring a secondary loop signal frequency of a transformer of a metering device.

In addition, the present embodiment also provides a computer readable storage medium, in which a computer program programmed or configured to execute the foregoing method for measuring the secondary loop signal frequency of the instrument transformer of the metering device is stored.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present application is directed to methods, apparatus (systems), and computer program products according to embodiments of the application wherein instructions, which execute via a flowchart and/or a processor of the computer program product, create means for implementing functions specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.