阅读说明：本技术 一种高频局部放电信号重构方法及系统 (High-frequency partial discharge signal reconstruction method and system ) 是由 何宁辉 张佩 丁培 马飞越 周秀 郝金鹏 田禄 刘威峰 倪辉 牛勃 于 2020-06-11 设计创作，主要内容包括：本申请公开一种高频局部放电信号重构方法及系统。所述方法包括可编程脉冲序列发生装置输出电压波形U<Sub>1</Sub>,通过高频耦合发射出去,产生电流I<Sub>1</Sub>；高频电流传感器接收局放产生的电流I<Sub>0</Sub>,通过自身传输阻抗将局放电流I<Sub>0</Sub>转换为示波器能够存储的电压波形U<Sub>0</Sub>；可编程脉冲序列发生装置输出的电压波形U<Sub>1</Sub>与局放电流I<Sub>0</Sub>相同,电流I<Sub>1</Sub>与电流I<Sub>0</Sub>波形相同,由此实现高频脉冲电流的波形重构。采用本申请提供的高频局部放电信号重构方法及系统,能够完整的复现变电站现场真实场景下的典型局部放电信号。(The application discloses a high-frequency partial discharge signal reconstruction method and system. The method comprises the steps of generating a voltage waveform U by a programmable pulse sequence generator 1 Is emitted by high-frequency coupling to generate a current I 1 (ii) a The high-frequency current sensor receives the current I generated by partial discharge 0 The partial discharge current I is transmitted through the self transmission impedance 0 Converting to a voltage waveform U storable by an oscilloscope 0 (ii) a Voltage waveform U output by programmable pulse sequence generator 1 And a partial discharge current I 0 Same, current I 1 And current I 0 The waveforms are the same, so that the waveform reconstruction of the high-frequency pulse current is realized. By the high-frequency partial discharge signal reconstruction method and system, typical partial discharge signals under real scene of a transformer substation site can be completely reproduced.)

1. A method for reconstructing a high frequency partial discharge signal, comprising:

programmable pulse sequence generator output voltage waveform U₁Is emitted by high-frequency coupling to generate a current I₁；

The high-frequency current sensor receives the current I generated by partial discharge₀The partial discharge current I is transmitted through the self transmission impedance₀Converting to a voltage waveform U storable by an oscilloscope₀；

Voltage waveform U output by programmable pulse sequence generator₁And a partial discharge current I₀Same, current I₁And current I₀The waveforms are the same, so that the waveform reconstruction of the high-frequency pulse current is realized.

2. The high-frequency partial discharge signal reconstruction method according to claim 1, wherein a current generated by partial discharge of the partial discharge source is I₀Current I of₀Flowing through the high-frequency current sensor as a receiving device with transmission impedance Z (j omega), and converting into voltage waveform U which can be stored in an oscilloscope₀。

3. The high-frequency partial discharge signal reconstruction method according to claim 2, characterized in that the signal input I₀And U₀The relationship of (a) is shown as follows:

U_o(jw)＝I₀(jw)Z(jw)

wherein Z (j ω) is the transmission impedance of the high-frequency current sensor.

4. The high-frequency partial discharge signal reconstruction method according to claim 3, wherein the signal source outputs a signal waveform U₁And U₀The relationship of (1) is:

U₁(jw)＝U₀(jw)/Z(jw)＝I₀(jw)

thus U is₁With the original pulse current I₀Same waveform, U₁Output current I through 50 omega resistor₁，I₁Is also related to₀The waveforms are the same.

5. A high frequency partial discharge signal reconstruction system, comprising: the device comprises a programmable pulse sequence generating device, a power divider, a high-frequency current sensor, an oscilloscope and a broadband impedance matching unit;

the calibration signal output by the programmable pulse sequence generator is connected with an RF power distributor with the characteristic impedance of 50 omega through a high-frequency coaxial feeder line, the calibration signal is divided into two paths to be output, one path of the calibration signal is connected with an oscilloscope through a high-frequency coaxial line and used for observing the output of the programmable pulse sequence generator, and the other path of the calibration signal is connected with a broadband impedance matching unit used for calibrating a high-frequency current sensor through the high-frequency coaxial line; wherein the characteristic impedances of the coaxial transmission lines are all 50 omega.

6. The system for reconstructing high-frequency partial discharge signals according to claim 5, wherein the high-frequency coupling tool is used for mounting a calibrated high-frequency current sensor and is a transmission line structure formed by deforming an RF coaxial line with the characteristic impedance of 50 Ω.

7. The high-frequency partial discharge signal reconstruction system of claim 6, wherein an interference signal loop is added to the high-frequency coupling tool to simulate high-frequency interference signals in a substation environment.

8. The high-frequency partial discharge signal reconstruction system of claim 6, wherein the high-frequency coupling tool adopts a coaxial cavity with 50 Ω wave impedance, and the injection capacitor C0 adopts a high-frequency ceramic capacitor with 100pF ± 2%.

9. The system for reconstructing high frequency partial discharge signals according to claim 5, wherein the high frequency current sensor is clamped in the middle of the matching unit, the core wire and the outer shell of the matching unit have dimensions that satisfy a characteristic impedance of 50 Ω, the outer shell has dimensions that transition from the input and output terminals to the center to form a tapered transition structure that satisfies the requirement of wideband matching, and the output end of the matching unit is connected to a digital oscilloscope having an input impedance of 50 Ω through an RF coaxial cable to collect the voltage/current waveforms output by the signal source.

Technical Field

The application relates to the field of electrical equipment partial discharge information processing, in particular to a high-frequency partial discharge signal reconstruction method and system.

Background

Partial discharge detection is the most important technical means in the current operation state detection technology of the electrical equipment, and the function verification of partial discharge detection instruments is the primary premise of network access detection of the instruments. At present, the calibration for high-frequency partial discharge detection instruments at home and abroad mainly focuses on the performance assessment of high-frequency sensors, including the indexes of transmission impedance, sensitivity, linearity and the like of the sensors, and the calibration research for the mode identification function of the high-frequency partial discharge detection instrument is not reported yet.

The mode recognition function verification of the high-frequency partial discharge detector is mainly realized through two modes: one method is to go to the on-site actual measurement of the transformer substation, but the on-site partial discharge environment is complex and variable, the actual measurement has a lot of uncertainties, and the test is time-consuming and labor-consuming. The other method is to design a typical defect model of partial discharge and generate a partial discharge signal in a pressurization mode, but the method has no stability and mainly reflects the conditions that the signal amplitude is not adjustable, the discharge continuity cannot be ensured, the discharge type is switched inconveniently and the like.

Therefore, a high-frequency-based partial discharge signal reconstruction method is needed to completely reproduce a typical partial discharge signal of a real scene of a substation site.

Disclosure of Invention

In order to achieve the above purpose, the present application provides the following technical solutions:

a high frequency partial discharge signal reconstruction method, comprising:

the programmable pulse sequence generator outputs a voltage waveform U1, and the voltage waveform U1 is transmitted out through high-frequency coupling to generate a current I1;

the high-frequency current sensor receives current I0 generated by partial discharge, and converts the partial discharge current I0 into voltage waveform U0 which can be stored by an oscilloscope through self transmission impedance;

the voltage waveform U1 output by the programmable pulse sequence generator is the same as the partial discharge current I0, and the current I1 is the same as the current I0, so that the waveform reconstruction of the high-frequency pulse current is realized.

The method for reconstructing the high-frequency partial discharge signal comprises the steps that the current generated by partial discharge of the partial discharge source is I0, the current I0 flows through the high-frequency current sensor, the high-frequency current sensor serves as a receiving device, the transmission impedance of the high-frequency current sensor is Z (j omega), and the high-frequency current sensor is converted into the voltage waveform U0 which can be stored by the oscilloscope.

The method for reconstructing the high-frequency partial discharge signal, wherein the relationship between the signal input I0 and U0 is shown as follows:

U_o(jw)＝I₀(jw)Z(jw)

wherein Z (j ω) is the transmission impedance of the high-frequency current sensor.

The method for reconstructing a high-frequency partial discharge signal as described above, wherein the relationship between the signal source output signal waveforms U1 and U0 is:

U₁(jw)＝U₀(jw)/Z(jw)＝I₀(jw)

therefore, the waveform of U1 is the same as that of the original pulse current I0, U1 outputs a current I1 through a 50-ohm resistor, and I1 is also the same as that of I0.

The present application further provides a high-frequency partial discharge signal reconstruction system, including: the device comprises a programmable pulse sequence generating device, a power divider, a high-frequency current sensor, an oscilloscope and a broadband impedance matching unit;

the calibration signal output by the programmable pulse sequence generator is connected with an RF power distributor with the characteristic impedance of 50 omega through a high-frequency coaxial feeder line, the calibration signal is divided into two paths to be output, one path of the calibration signal is connected with an oscilloscope through a high-frequency coaxial line and used for observing the output of the programmable pulse sequence generator, and the other path of the calibration signal is connected with a broadband impedance matching unit used for calibrating a high-frequency current sensor through the high-frequency coaxial line; wherein the characteristic impedances of the coaxial transmission lines are all 50 omega.

The high-frequency partial discharge signal reconstruction system is characterized in that the high-frequency coupling tool is used for mounting a calibrated high-frequency current sensor and is a transmission line structure formed by deforming an RF coaxial line with the characteristic impedance of 50 omega.

According to the high-frequency partial discharge signal reconstruction system, an interference signal loop is added in the high-frequency coupling tool to simulate the high-frequency interference signal in the environment of the transformer substation.

In the high-frequency partial discharge signal reconstruction system, the high-frequency coupling tool adopts a coaxial cavity with 50 Ω wave impedance, and the injection capacitor C0 adopts a high-frequency ceramic capacitor with 100pF +/-2%.

The high-frequency partial discharge signal reconstruction system comprises a high-frequency current sensor, a matching unit, a conical transition structure and a signal source, wherein the high-frequency current sensor is clamped in the middle of the matching unit, the size of a core wire and the size of a shell of the matching unit meet the requirement that the characteristic impedance is 50 ohms, the size of the shell is transited from an input terminal and an output terminal to the center to form the conical transition structure, the broadband matching requirement is met, the output end of the matching unit is connected to a digital oscilloscope with the input impedance being 50 ohms through an RF coaxial cable, and the voltage/.

By the high-frequency partial discharge signal reconstruction method and system, typical partial discharge signals under real scene of a transformer substation site can be completely reproduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to the drawings.

Fig. 1 is a structural diagram of a high-frequency coupling tool provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a high frequency coupling tool;

fig. 3 is a schematic diagram of a high frequency signal reconstruction process.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.