阅读说明：本技术 一种空气间隙放电发射光谱时空分布的观测方法 (Method for observing space-time distribution of air gap discharge emission spectrum ) 是由 韩永霞 郑文博 杨杰 张垭琦 高毓群 刘刚 张福增 王国利 王婷婷 廖一帆 于 2019-08-16 设计创作，主要内容包括：本发明公开了一种空气间隙放电发射光谱时空分布的观测方法,通过设置光栅光谱仪的触发时延及其像增强探测器的增益,并对各种信号传输时间延迟进行校正,可以得到精确且分辨率高的标准雷电冲击下空气间隙放电发射光谱的时空分布。本发明提供的标准雷电冲击下空气间隙放电发射光谱时空分布的观测方法用于电力系统防雷设计的研究。(the invention discloses an observation method of air gap discharge emission spectrum space-time distribution, which can obtain the accurate and high-resolution space-time distribution of the air gap discharge emission spectrum under standard lightning impulse by setting the trigger time delay of a grating spectrometer and the gain of an image enhancement detector and correcting various signal transmission time delays. The observation method of the air gap discharge emission spectrum space-time distribution under the standard lightning impulse is used for researching the lightning protection design of the power system.)

1. A method for observing the space-time distribution of an air gap discharge emission spectrum is characterized by comprising the following steps:

S1, measuring the 50% breakdown discharge voltage U50% of air gap discharge under standard lightning impulse;

s2, applying standard lightning impulse voltage at two ends of the air gap, wherein the amplitude of the applied voltage is kU 50%;

S3, repeatedly discharging for a fixed impulse voltage amplitude, setting a trigger time delay, shooting a complete and clear air gap discharge channel image by using a grating spectrometer, and then adjusting the position and the shooting focal length of the grating spectrometer according to the position of the discharge channel in the image to enable the air gap discharge channel to be positioned at the center of the image and enable the slit width of the grating spectrometer to be as small as possible;

S4, shooting a 0-1000 nm full-waveband emission spectrogram of an air gap discharge channel, and selecting and recording a central wavelength value corresponding to a spectral line with an obvious peak;

S5, setting the triggering time delay to be the minimum value in a voltage pulse period, setting the central wavelength and the shooting interval of the shooting of the grating spectrometer, and obtaining the air gap discharge emission spectrogram corresponding to the central wavelength value selected in the step S4 from the wave head of the voltage pulse to obtain the space-time distribution under the condition of no gain;

s6, if the intensity of the obtained air gap discharge emission spectrogram is insufficient, the gain multiple of the image enhancement detector of the grating spectrometer is increased in a stepping mode until the emission spectrum with sufficient intensity is shot or the gain multiple of the image enhancement detector reaches the upper limit, and then the step S7 is carried out;

If the intensity of the obtained air gap discharge emission spectrogram is enough, directly entering S7;

s7, sequencing emission spectrograms with sufficient intensity according to the positions of pulse voltages at moments in a period to obtain the space-time distribution of an air gap discharge emission spectrum under standard lightning impulse;

and S8, correcting the transmission delay of the space-time distribution of the air gap discharge emission spectrum under the standard lightning impulse obtained in S7 to obtain the space-time distribution of the air gap discharge emission spectrum under the standard lightning impulse.

2. the observation method according to claim 1, wherein in S3, the exposure time for each shot of the air gap discharge emission spectrum is set to 3ns, and the gain factor of the image intensifier detector is 1.

3. the observation method of claim 1, wherein in S3, the oscilloscope sends the trigger signal to the image enhancement detector at the moment when the trigger level is reached, and the time interval between the moment when the image enhancement detector receives the trigger signal and the moment when the exposure is started is the trigger delay.

4. The observation method according to claim 1, wherein the shooting interval in S5 is set to 50 ns.

5. The observation method of claim 1, wherein in the step S8, the transmission delay comprises a transmission time delay between the oscilloscope and the grating spectrometer, a transmission time delay of the impulse voltage generator signal to the oscilloscope, and a penalty time delay set by an image enhancement detector of the grating spectrometer.

6. observation method according to claim 1, wherein k has a value of 1.2, 1.3, 1.4, 1.5 or 1.6.

7. the observation method according to claim 1, wherein the waveform of the standard lightning surge voltage in S2 is 1.2/50 μ S.

8. The observation method according to claim 1, wherein the transmission delay is corrected by using the space-time distribution of the emission spectrum of the air gap discharge under the standard lightning impulse obtained in step S7, specifically:

when waveform data processing is carried out, the time axis of the impulse voltage waveform subtracts the time delay value of the impulse voltage generator signal transmitted to the oscilloscope, the image enhancement detector feeds back the time axis of the monitoring signal of the oscilloscope minus the transmission time delay value between the oscilloscope and the grating spectrometer, the actual time position of each group of discharge emission spectrograms in the pulse voltage period can be determined, and the discharge emission spectrograms space-time distribution under the standard lightning impulse is obtained.

Technical Field

The invention relates to the technical field of power systems, in particular to an observation method for air gap discharge emission spectrum space-time distribution.

Background

lightning is one of the main reasons for tripping of the power transmission line, so that research on the physical discharge mechanism, protective measures and numerical simulation methods of the air gap under lightning impact is the key and difficult point of the lightning protection of the power system.

disclosure of Invention

in order to overcome the defects and shortcomings of the prior art, the invention provides an observation method of air gap discharge emission spectrum space-time distribution under standard lightning impulse, which is used for obtaining more accurate and higher-resolution space-time distribution of air gap discharge emission spectrum under standard lightning impulse, promoting the depth degree of research on physical discharge mechanism of air gap under standard lightning impulse and finally promoting the improvement of lightning protection level of a power system.

the invention adopts the following technical scheme:

A method for observing the space-time distribution of an air gap discharge emission spectrum comprises the following steps:

S1, measuring the 50% breakdown discharge voltage U50% of air gap discharge under standard lightning impulse;

S2, applying standard lightning impulse voltage at two ends of the air gap, wherein the amplitude of the applied voltage is kU 50%;

S3, repeatedly discharging for a fixed impulse voltage amplitude, setting a trigger time delay, shooting a complete and clear air gap discharge channel image by using a grating spectrometer, and then adjusting the position and the shooting focal length of the grating spectrometer according to the position of the discharge channel in the image to enable the air gap discharge channel to be positioned at the center of the image and enable the slit width of the grating spectrometer to be as small as possible;

S4, shooting a 0-1000 nm full-waveband emission spectrogram of an air gap discharge channel, and selecting and recording a central wavelength value corresponding to a spectral line with an obvious peak;

s5, setting the triggering time delay to be the minimum value in a voltage pulse period, setting the central wavelength shot by the grating spectrometer, and obtaining the air gap discharge emission spectrogram corresponding to the central wavelength value selected in the step S4 from the wave head of the voltage pulse to obtain the space-time distribution under the condition of no gain;

s6, if the intensity of the obtained air gap discharge emission spectrogram is insufficient, the gain multiple of the image enhancement detector of the grating spectrometer is increased in a stepping mode until the emission spectrum with sufficient intensity is shot or the gain multiple of the image enhancement detector reaches the upper limit, and then the step S7 is carried out;

If the intensity of the obtained air gap discharge emission spectrogram is enough, directly entering S7;

S7, sequencing emission spectrograms with sufficient intensity according to the positions of pulse voltages at moments in a period to obtain the space-time distribution of an air gap discharge emission spectrum under standard lightning impulse;

And S8, correcting the transmission delay of the space-time distribution of the air gap discharge emission spectrum under the standard lightning impulse obtained in S7 to obtain the space-time distribution of the air gap discharge emission spectrum under the standard lightning impulse.

In S3, the exposure time for each shot of the air gap discharge emission spectrum is set to 3ns, and the gain multiple of the image intensifier detector is 1.

In S3, the oscilloscope sends a trigger signal to the image intensifier detector when the oscilloscope reaches a trigger level, and a time interval between when the image intensifier detector receives the trigger signal and when the image intensifier detector starts to expose is trigger delay.

The shooting interval in S5 is set to 50 ns.

In S8, the transmission delay includes a transmission time delay between the oscilloscope and the grating spectrometer, a time delay for transmitting the impulse voltage generator signal to the oscilloscope, and a penalty time delay set by the image enhancement detector of the grating spectrometer.

The value of k is 1.2, 1.3, 1.4, 1.5 or 1.6.

the waveform of the standard lightning surge voltage in S2 is 1.2/50 mus.

the correction of the transmission delay is carried out on the space-time distribution of the air gap discharge emission spectrum under the standard lightning impulse obtained in the step S7, which specifically comprises the following steps:

When waveform data processing is carried out, the time axis of the impulse voltage waveform subtracts the time delay value of the impulse voltage generator signal transmitted to the oscilloscope, the image enhancement detector feeds back the time axis of the monitoring signal of the oscilloscope minus the transmission time delay value between the oscilloscope and the grating spectrometer, the actual time position of each group of discharge emission spectrograms in the pulse voltage period can be determined, and the discharge emission spectrograms space-time distribution under the standard lightning impulse is obtained.

The invention has the beneficial effects that:

(1) Setting the exposure time of each emission spectrogram to be 3ns, carrying out repeated discharge by fixing the amplitude of impulse voltage, shooting a group of air gap discharge emission spectrograms at intervals of 50ns in an impulse voltage period, aiming at the weak discharge phenomenon in the early corona starting and streamer development stages, obtaining an emission spectrum with sufficient strength by increasing the gain multiple of an image enhancement detector of a grating spectrometer, and comprehensively considering the transmission time delay between an oscilloscope and the grating spectrometer, the time delay of transmitting an impulse voltage generator signal to the oscilloscope and the trigger time delay set by the grating spectrometer, and finally obtaining more accurate and higher-resolution time-space distribution of the air gap discharge emission spectrum under the standard lightning impact;

(2) Compared with the prior art, the emission spectrum space-time distribution of air gap discharge under standard lightning impulse obtained by the invention has the advantages that the intensity, the resolution and the time distribution accuracy of the emission spectrum are equally and greatly improved, the emission spectrum space-time distribution can be used for obtaining the emission spectrum of m-level long air gap discharge, the deep research on the discharge physical mechanism of the air gap under standard lightning impulse is facilitated, and the lightning protection level of a power system is finally improved.

Drawings

FIG. 1 is a flow chart of the operation of the present invention;

Fig. 2 is a schematic diagram of a hardware architecture implementation of the present invention.

Detailed Description

the present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited to these examples.