CN103412228B - A kind of Frequency Response Test Method of distribution transformer - Google Patents

Abstract

The present invention relates to a kind of winding deformation of power transformer frequency response method of testing.The Frequency Response Test Method of a kind of distribution transformer, it is characterised in that the signal injection end in Transformer Winding will input signal digitized；Signal responder in Transformer Winding will output signal digitized；By wireless network, digitized input signal and output signal collection are got up and carry out calculating the frequency response obtaining transformator.And adopt distributed digital signal processing method, it is possible to thoroughly solve signal to noise ratio problem.Meanwhile, namely it is respectively adopted intelligent terminal at signal injection end and outfan, completes digitized and by being wirelessly transferred, it is possible to solve the impact on test data of ground connection distributed constant and cable distributed constant.

Description

A kind of Frequency Response Test Method of distribution transformer

Technical field

The present invention relates to a kind of winding deformation of power transformer frequency response method of testing.

Background technology

Since promulgating from power industry standard DL/T911-2004 " winding deformation of power transformer frequency response analysis ", spend the time of nearly 10 years, through application for many years, summary, the process of method of testing and test data has suitable lifting.Owing to frequency response method of testing is tested, frequency is very wide is generally 1kHz-2MHz, especially because the impact of ground connection and distributed constant, it is easy to cause the error of test result.A kind of distributed deformation of transformer winding method of testing is proposed at this.

One, test philosophy:

Under the voltage effect of upper frequency, each winding of transformator all can be considered a passive linear two-port network being made up of linear resistance, inductance (mutual inductance), electric capacity equal distribution parameter, its bulk properties can be passed through transfer function H (j ω) and describe, as shown in Figure 1.If winding deforms, the parameter such as distributed inductance within winding, electric capacity necessarily changes, and causes that the zero point of its equivalent network transfer function H (j ω) and limit change, makes the frequency response characteristic of network change.

Detect deformation of transformer winding with frequency response analysis, be the amplitude-frequency response characteristic by detecting each winding of transformator, and testing result is carried out vertical or horizontal comparison, the difference according to amplitude-frequency response characteristic, it is judged that the contingent winding deformation of transformator.

The amplitude-frequency response characteristic of Transformer Winding adopts the frequency sweep mode shown in Fig. 1 to obtain.Change the outer frequency f (angular frequency=2 π f) executing sine-wave excitation source Vs continuously, measure the ratio of the signal amplitude of responder voltage V2 at different frequencies and excitation terminal voltage V1, it is thus achieved that specify the amplitude-frequency response of winding in excitation end and responder situation.In Fig. 1: L, K and C represent the distributed inductance of winding unit length, distribution capacity and distribution capacity over the ground respectively, the excitation terminal voltage of V1, V2 respectively equivalent network and responder voltage, Vs is sine wave exciting signal source voltage, and Rs is signal source output impedance, and R is build-out resistor.

In sum, the signal of transformator is usually moved to and is tested on ground by traditional winding deformation of power transformer frequency response method of testing, and such test is usually present two technical problems:

One: owing to frequency response signal is little, frequency is high, originally test cable longer (about 20 meters), signal is easy to be disturbed；

As in figure 2 it is shown, its two: system has a more distributed constant, and distributed constant exists feature that is unstable and that change greatly, and the result of frequency sound test is had a certain impact.

Summary of the invention

It is an object of the invention to overcome above-mentioned deficiency existing in prior art, it is provided that the Frequency Response Test Method of a kind of distribution transformer, to thoroughly solving one, signal to noise ratio problem；Two, the impact on test data of ground connection distributed constant and cable distributed constant is solved.In order to realize foregoing invention purpose, the invention provides techniques below scheme:

The Frequency Response Test Method of a kind of distribution transformer, the signal injection end in Transformer Winding will input signal digitized；Signal responder in Transformer Winding will output signal digitized；By wireless network, digitized input signal and output signal collection are got up and carry out calculating the Frequency Response of transformator.

The Frequency Response Test Method of described a kind of distribution transformer is specifically:

The first step: systems soft ware sends out output drive signal by the controlled in wireless end of main control unit to the first test cell, the first test cell response, output drive signal, and be loaded in described Transformer Winding；

Second step: software sends startup test signal by the controlled in wireless end of main control unit to the first test cell and the second test cell；

3rd step: test signal is responded by the first test cell and the second test cell, synchronous acquisition completes the analog digital conversion of signal and preserves data；4th step: software by, in the test signal collection of the first test cell and the second test cell to PC software, being calculated, process, obtains the frequency response of transformator by the controlled in wireless end of main control unit.

Described main control unit is that notebook computer is controlled by USB, and as shown in Figure 4, the program circuit of main control unit is as follows:

The first step: add and electrically activate；

Second step: initiating hardware；

3rd step: wait PC instruction；

4th step: if there being instruction, then analysis instruction, response instruction, if not having, then wait PC instruction；

5th step: if two test cell responses are normal, then send signal output order to the first test cell；If abnormal, return the 3rd step；

6th step: send out test starting command to two test cells, until having put measurement to last measurement.

First test cell, the second test cell all only receive the wireless control signal from main control unit responsing control command, as it is shown in figure 5, the program circuit of the first test cell, the second test cell is as follows:

The first step: add and electrically activate；

Second step: initiating hardware；

3rd step: wait main control unit instruction；

4th step: if there being instruction, then respond instruction, if not having, then returns the 3rd step.

Described software by the test signal collection of two unit to PC software by the controlled in wireless end of main control unit, is calculated, processes.

Described " software " belongs to as well known to those skilled in the art, does not repeat at this.

The collection data length assuming the first test cell and the second test cell is N, corresponding data queue is X (k), Y (k), k=0,1, ..., N-1, and X (k), Y (k) be real number, the computing formula of the coefficient R judged for winding deformation is as follows.

A.1 the standard variance of two sequences is calculated

$\mathrm{Dx}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[X\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}X\left(k\right){]}^2$ $\mathrm{Dy}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[Y\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}Y\left(k\right){]}^2$

A.2 the covariance of two sequences is calculated

$C_{\mathrm{xy}}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[X\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}X\left(k\right)]\×[Y\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}Y\left(k\right)]$

A.3 the normalized covariance coefficient of two sequences is calculated

${\mathrm{LR}}_{\mathrm{xy}}=\mathrm{Cxy}/\sqrt{\mathrm{DxDy}}$

A.4 the coefficient R meeting requirement of engineering is calculated according to equation below_xy

The Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 10Hz to 10MHz.

The Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 1KHz to 2MHz.

Compared with prior art, beneficial effects of the present invention:

One and adopt distributed digital signal processing method, it is possible to thoroughly solve signal to noise ratio problem.

Two, adopt the processing method of distributed digital, be namely respectively adopted intelligent terminal at signal injection end and outfan, complete digitized and by being wirelessly transferred, it is possible to solve the impact on test data of ground connection distributed constant and cable distributed constant.

Accompanying drawing illustrates:

Fig. 1 is deformation of transformer winding test schematic diagram；

Fig. 2 is system distributed constant schematic diagram；

Fig. 3 is that distributed signal processes system construction drawing；

Fig. 4 is the program flow diagram of main control unit；

Fig. 5 is the first test cell and the program flow diagram of the second test cell.

Detailed description of the invention

Below in conjunction with test example and detailed description of the invention, the present invention is described in further detail.But this should not being interpreted as, the scope of the above-mentioned theme of the present invention is only limitted to below example, and all technology realized based on present invention belong to the scope of the present invention.

The Frequency Response Test Method of a kind of distribution transformer, the signal injection end in Transformer Winding will input signal digitized；Signal responder in Transformer Winding will output signal digitized；By wireless network, digitized input signal and output signal collection are got up and carry out calculating the Frequency Response of Transformer Winding.

The Frequency Response Test Method of described a kind of distribution transformer is specifically:

The first step: systems soft ware sends out output drive signal by the controlled in wireless end of main control unit to the first test cell, the first test cell response, output drive signal, and be loaded in described Transformer Winding；

Second step: software sends startup test signal by the controlled in wireless end of main control unit to the first test cell and the second test cell；

3rd step: test signal is responded by the first test cell and the second test cell, synchronous acquisition completes the analog digital conversion of signal and preserves data；4th step: software by, in the test signal collection of the first test cell and the second test cell to PC software, being calculated, process, obtains the Frequency Response of Transformer Winding by the controlled in wireless end of main control unit.

Fig. 3 is that distributed signal processes system construction drawing.

Described main control unit is that notebook computer is controlled by USB, and as shown in Figure 4, the program circuit of main control unit is as follows:

The first step: add and electrically activate；

Second step: initiating hardware；

3rd step: wait PC instruction；

4th step: if there being instruction, then analysis instruction, response instruction, if not having, then wait PC instruction；

5th step: if two test cell responses are normal, then send signal output order to the first test cell；If abnormal, return the 3rd step；

6th step: send out test starting command to two test cells, until having put measurement to last measurement.

First test cell, the second test cell all only receive the wireless control signal from main control unit responsing control command, as it is shown in figure 5, the program circuit of the first test cell, the second test cell is as follows:

The first step: add and electrically activate；

Second step: initiating hardware；

3rd step: wait main control unit instruction；

4th step: if there being instruction, then respond instruction, if not having, then returns the 3rd step.

Described software by the test signal collection of two unit to PC software by the controlled in wireless end of main control unit, is calculated, processes.

Described " software " belongs to as well known to those skilled in the art, does not repeat at this.

The collection data length assuming the first test cell and the second test cell is N, corresponding data queue is X (k), Y (k), k=0,1, ..., N-1, and X (k), Y (k) be real number, the computing formula of the coefficient R judged for winding deformation is as follows.

A.1 the standard variance of two sequences is calculated

$\mathrm{Dx}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[X\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}X\left(k\right){]}^2$ $\mathrm{Dy}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[Y\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}Y\left(k\right){]}^2$

A.2 the covariance of two sequences is calculated

$C_{\mathrm{xy}}=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}[X\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}X\left(k\right)]\×[Y\left(k\right)-\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}Y\left(k\right)]$

A.3 the normalized covariance coefficient of two sequences is calculated

${\mathrm{LR}}_{\mathrm{xy}}=\mathrm{Cxy}/\sqrt{\mathrm{DxDy}}$

A.4 the coefficient R meeting requirement of engineering is calculated according to equation below_xy

The Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 10Hz to 10MHz.

The Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 1KHz to 2MHz.

Claims (3)

1. the Frequency Response Test Method of a distribution transformer, it is characterised in that the signal injection end in Transformer Winding will input signal digitized；Signal responder in Transformer Winding will output signal digitized；By wireless network, digitized input signal and output signal collection are got up and carry out calculating the Frequency Response of transformator；

Frequency Response Test Method is specifically:

The first step: systems soft ware sends out output drive signal by the controlled in wireless end of main control unit to the first test cell, the first test cell response, output drive signal, and be loaded in described Transformer Winding；

Second step: systems soft ware sends startup test signal by the controlled in wireless end of main control unit to the first test cell and the second test cell；

3rd step: test signal is responded by the first test cell and the second test cell, synchronous acquisition completes the analog digital conversion of signal and preserves data；

4th step: the data collection that the first test cell and the second test cell in the 3rd step have been processed by the controlled in wireless end of main control unit by systems soft ware, in PC software, is calculated, processes, obtain the frequency response of transformator.

2. the Frequency Response Test Method of a kind of distribution transformer as claimed in claim 1, it is characterised in that the Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 10Hz to 10MHz.

3. the Frequency Response Test Method of a kind of distribution transformer as claimed in claim 1, it is characterised in that the Hz-KHz of the Frequency Response Test Method of described a kind of distribution transformer is 1KHz to 2MHz.