A system and method for detecting discharge information inside GIS

Abstract

The present invention discloses a system and method for detecting discharge information inside GIS, belonging to the technical field of power transmission and transformation equipment. The system of the present invention comprises: a solar-blind single-photon detector, a UHF sensor, a high-frequency current sensor, an acquisition card and a processing device. The processing device is used to determine whether there is discharge inside the GIS by comparing whether the acquisition channel has acquired a voltage signal, a UHF signal or a pulse current. When it is determined that there is discharge inside the GIS, the discharge information inside the GIS is detected according to the voltage signal, the UHF signal or the pulse current acquired by the acquisition channel. The present invention improves the measurement sensitivity, anti-interference performance, and diagnostic accuracy of the GIS internal discharge, and the reliability of the diagnostic results, and can realize single-photon detection and diagnosis of GIS internal discharge. The detection band is a solar-blind ultraviolet band, and can realize discharge type identification, discharge amount measurement, and other functions.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission and transformation equipment, and more specifically, to a system and method for detecting internal discharge information of a GIS. Background Art

[0002] With the widespread application of gas-insulated switchgear (GIS), the operational reliability of GIS equipment has gradually attracted widespread attention from the international community and the power sector. From the operating experience of nearly 40 years, insulation failure has always been one of the important factors affecting GIS reliability. Partial discharge is the main manifestation of insulation degradation of GIS equipment until flashover failure occurs. According to the location of discharge, typical discharge defects inside GIS are mainly divided into two categories: discharge defects in SF6 gas and discharge defects in solid insulation (pot insulators, supporting insulators). Among them, discharge defects in SF6 gas can be divided into tip discharge on high-voltage conductors (busbars), tip discharge on the low-voltage side (GIS shell), floating potential discharge on the high-voltage side, floating potential discharge on the low-voltage side, and suspended discharge of poor contact type; discharge defects on insulators can be divided into dirty insulator surface, metal particles, and cracks or air gaps inside insulators; considering the location of discharge, discharge defects on insulators are prone to induce surface flashover failures, and their harmfulness is greater than that of discharges in SF6 gas.

[0003] Inside the GIS equipment, the duration of the partial discharge pulse is very short, and the rise time of the wave head is only about 1ns. This extremely short-duration steep pulse contains partial discharge electromagnetic wave signals up to GHz. Partial discharge will generate flowing electromagnetic waves on the GIS equipment shell. A high-frequency discharge pulse current flows through the grounding wire, and the shell presents a high-frequency voltage to the ground and generates electromagnetic waves to the surrounding space. Partial discharge will also cause a sudden increase in the channel gas pressure, generate ultrasonic waves in the GIS equipment gas, and reflect and transmit when it reaches the metal shell, and various sound waves will appear on the metal shell, such as longitudinal waves, transverse waves and surface waves. Partial discharge in GIS equipment also generates light and decomposes SF6 gas. These physical and chemical effect changes accompanying partial discharge are the basis for realizing online detection of GIS equipment. At present, the main methods widely used on site are ultra-high frequency method, ultrasonic method, and SF6 gas decomposition product analysis.

[0004] The ultrasonic method has low detection sensitivity. It is not sensitive enough for detecting some types of internal insulation discharge defects, but it is better for detecting free metal particle faults. At the same time, this method is relatively difficult to judge the type of discharge fault and cannot realize the calibration of the apparent discharge amount. The ultra-high frequency (UHF) method has high sensitivity, but it is difficult to characterize the severity of partial discharge with the amplitude of the ultra-high frequency signal, and it is difficult to realize the calibration of the apparent discharge amount. For the gas decomposition product analysis method, since there is no clear correlation between the type of partial discharge insulation defects and the decomposition components of SF6 gas during the discharge development process, there is no mature guideline and judgment standard like transformer oil chromatography analysis. It still needs a lot of research work from the accumulation of laboratory simulation defect faults and field fault cases, which leads to the fact that this method cannot accurately judge the fault type and be applied to actual online monitoring.

[0005] In S F6 In the gas, the spectrum of corona discharge radiation is mainly concentrated in the near-ultraviolet region, among which there is a continuous spectrum peak in the near-ultraviolet region of 250nm to 400nm, which provides an important basis for the spectral range of photoelectric detection. At present, there are many optical methods for discharge detection of power equipment, which are mainly divided into optical imaging method and optical pulse method, and are implemented by infrared imagers, ultraviolet imagers and other equipment. This type of method relies on expensive optical measurement and display equipment, and has the disadvantages of high cost, complex operation, insufficient sensitivity, difficulty in predicting early discharge dangers, and inability to quantitatively indicate the degree of discharge. Therefore, it is urgent to propose a low-cost, high-sensitivity and effective photoelectric combined diagnosis system for detecting local discharge in GIS. Summary of the invention

[0006] In order to realize partial discharge measurement and discharge type diagnosis in GIS, improve the sensitivity of partial discharge measurement, anti-interference performance, diagnosis accuracy and reliability of diagnosis results, the present invention proposes a system for detecting discharge information inside GIS, including:

[0007] A solar-blind single-photon detector is used to detect whether the internal discharge of the GIS generates an ultraviolet light signal. When the internal discharge of the GIS generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the internal discharge of the GIS. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card;

[0008] The UHF sensor is used to detect whether the internal discharge of the GIS generates a UHF signal. When the internal discharge of the GIS generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card;

[0009] High-frequency current sensor is used to detect whether the internal discharge of GIS generates pulse current. When the internal discharge of GIS generates pulse current, the high-frequency current sensor receives the pulse current generated by the internal discharge of GIS and transmits it to the acquisition card;

[0010] An acquisition card having multiple acquisition channels, each of which is provided with a trigger level. When the amplitude of a voltage signal, a UHF signal or a pulse current received by any channel is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to synchronously acquire the voltage signal, the UHF signal and the pulse current through multiple channels; and

[0011] The processing device is used to determine whether there is discharge inside the GIS by comparing whether the acquisition channel has collected voltage signals, ultra-high frequency signals or pulse currents. When it is determined that there is discharge inside the GIS, the discharge information inside the GIS is detected according to the voltage signals, ultra-high frequency signals or pulse currents collected by the acquisition channel.

[0012] Optionally, the discharge information includes: discharge type, discharge amount and corona area.

[0013] Optionally, the acquisition card can be set to perform synchronous acquisition on multiple acquisition channels after a specific channel is triggered.

[0014] Optionally, the specific channels include: a voltage signal trigger channel, a UHF signal trigger channel and a pulse current signal trigger channel.

[0015] Optionally, the processing device identifies the GIS discharge type by drawing a time-domain pulse sequence spectrum and a phase spectrum of the voltage signal, UHF signal or pulse current collected by the collection channel and comparing them with a standard discharge spectrum.

[0016] Optionally, the processing device calculates the discharge corona area by counting the number of photons during the discharge period, and calculates the discharge amount in combination with the current pulse signal.

[0017] The present invention also proposes a method for detecting discharge information inside a GIS, comprising:

[0018] The solar-blind single-photon detector detects whether the GIS discharge generates an ultraviolet light signal. When the GIS discharge generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the GIS discharge. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card.

[0019] The UHF sensor detects whether the GIS discharge generates a UHF signal. When the GIS discharge generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card.

[0020] The high-frequency current sensor detects whether the GIS discharge generates pulse current. When the GIS discharge generates pulse current, the high-frequency current sensor receives the pulse current generated by the GIS discharge and transmits it to the acquisition card;

[0021] When the amplitude of the voltage signal, UHF signal or pulse current received by any channel of the acquisition card is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to synchronously acquire the voltage signal, UHF signal and pulse current through multiple channels;

[0022] The processing device determines whether the GIS is discharged by comparing whether the acquisition channel has collected voltage signals, ultra-high frequency signals or pulse currents. When it is determined that the GIS is discharged, the GIS discharge information is detected based on the voltage signals, ultra-high frequency signals or pulse currents collected by the acquisition channel.

[0023] Optionally, the discharge information includes: discharge type, discharge amount and corona area.

[0024] Optionally, determine whether the GIS is discharging based on the collection results, specifically: if the solar-blind single-photon detector, UHF sensor and high-frequency current sensor all transmit signals, there must be discharge; if the solar-blind single-photon detector and UHF sensor have signals, but the high-frequency current sensor has no signal, there is discharge, the discharge is relatively weak and the optical path is not blocked; if the solar-blind single-photon detector and high-frequency current sensor have no signals, but the UHF sensor has a signal, there is discharge, the discharge is relatively weak and the optical path is blocked; if the solar-blind single-photon detector, high-frequency current sensor and UHF sensor all have no signals, there is no discharge.

[0025] Optionally, the identification of the discharge type includes: determining the discharge type after performing PRPD spectrum analysis of the voltage signal, the UHF signal and the pulse current according to a discharge identification basis, wherein the discharge identification basis is obtained by pre-discharging through a standard electrode and calibrating the system.

[0026] Optionally, detection of discharge volume and corona area includes:

[0027] The ultraviolet light signal photons first pass through the incident window and enter the photomultiplier tube of the solar-blind single-photon detector, where they are received by the photocathode and converted into electrons to form and output a photocurrent I c , the processing device calculates the photocurrent I according to the following formula c , photocurrent I c That is the discharge amount:

[0028] I c =n·QE·q

[0029] Where n is the number of photons received by the cathode per unit time, QE is the quantum efficiency of the photomultiplier tube, and q is the electron charge;

[0030] Single photon detection of ultraviolet light signal pulses, the number of light pulses is the number of photons, and the relationship between the number of photons N and the relative corona area S is:

[0031] N=k∫∫η(λ)ds+n+M

[0032] Where k is the relative coefficient of the corona area, η(λ) is the photon radiation efficiency. When there is less ozone in the corona, η(λ) = 1, and it decreases with the increase of ozone concentration. n is the total number of dark current pulses in the test, and M is the amount of ultraviolet signal photons generated by the outer layer of the corona.

[0033] The present invention can realize single-photon detection and diagnosis of discharge inside GIS. The detection band is the solar-blind ultraviolet band, and can realize functions such as discharge type identification and discharge amount measurement.

[0034] The present invention highly integrates a solar-blind single-photon detector, an ultra-high frequency sensor, and a high-frequency current sensor. The three sensors can be directly connected to an acquisition card, and the acquisition card is used to realize synchronous acquisition of optical-electrical signals. The processing device automatically judges the existence of discharge, and can judge the optical path and electrical obstacle shielding between the discharge source and the sensor, which improves the reliability and sensitivity of detection compared with using only a single sensor. The processing device automatically calculates the PRPD spectrum and the time-domain pulse sequence spectrum of the optical-electrical signal pulse, and compares them with the standard discharge mode spectrum pre-calibrated by the system to obtain the closest discharge type, thereby realizing the recognition of the discharge type, and improving the accuracy and sensitivity of recognition compared with using only the ultra-high frequency detection method. The processing device counts the pulses of the optical pulse sequence, automatically calculates the corona area during discharge, and then combines the current pulse sequence to obtain the optical-current pulse sequence, and automatically calculates the discharge amount, which improves the sensitivity of the discharge amount calculation compared with using only the current pulse method. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a system structure diagram for detecting internal discharge information of GIS according to the present invention;

[0036] Figure 2 The present invention is a flow chart of a method for detecting discharge information inside GIS. DETAILED DESCRIPTION

[0037] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0038] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0039] The present invention proposes a system for detecting discharge information inside GIS, such as Figure 1 As shown, including:

[0040] A solar-blind single-photon detector is used to detect whether the internal discharge of the GIS generates an ultraviolet light signal. When the internal discharge of the GIS generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the internal discharge of the GIS. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card;

[0041] The UHF sensor is used to detect whether the internal discharge of the GIS generates a UHF signal. When the internal discharge of the GIS generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card;

[0042] High-frequency current sensor is used to detect whether the internal discharge of GIS generates pulse current. When the internal discharge of GIS generates pulse current, the high-frequency current sensor receives the pulse current generated by the internal discharge of GIS and transmits it to the acquisition card;

[0043] The acquisition card has multiple acquisition channels, each of which is set with a trigger level. When the amplitude of the voltage signal, ultra-high frequency signal or pulse current received by any channel is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to perform multi-channel synchronous acquisition of the voltage signal, ultra-high frequency signal and pulse current. The acquisition card can be set to perform multi-channel synchronous acquisition after a specific channel is triggered. The specific channels include: voltage signal trigger channel, ultra-high frequency signal trigger channel and pulse current signal trigger channel;

[0044] The processing equipment is used to determine whether there is discharge inside the GIS by comparing whether the acquisition channel has collected voltage signals, ultra-high frequency signals or pulse currents. When it is determined that there is discharge inside the GIS, the internal discharge information of the GIS is detected according to the voltage signals, ultra-high frequency signals or pulse currents collected by the acquisition channel. The discharge information includes: discharge type, discharge amount and corona area. The processing equipment identifies the GIS discharge type by drawing the time domain pulse sequence spectrum and phase spectrum of the voltage signal, ultra-high frequency signal or pulse current collected by the acquisition channel and comparing them with the standard discharge spectrum. The processing equipment calculates the discharge corona area by counting the number of photons during the discharge period, and calculates the discharge amount in combination with the current pulse signal.

[0045] The present invention also proposes a method for detecting discharge information inside GIS, such as Figure 2 As shown, including:

[0046] The solar-blind single-photon detector detects whether the GIS discharge generates an ultraviolet light signal. When the GIS discharge generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the GIS discharge. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card.

[0047] The UHF sensor detects whether the GIS discharge generates a UHF signal. When the GIS discharge generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card.

[0048] The high-frequency current sensor detects whether the GIS discharge generates pulse current. When the GIS discharge generates pulse current, the high-frequency current sensor receives the pulse current generated by the GIS discharge and transmits it to the acquisition card;

[0049] When the amplitude of the voltage signal, UHF signal or pulse current received by any channel of the acquisition card is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to synchronously acquire the voltage signal, UHF signal and pulse current through multiple channels;

[0050] The processing equipment determines whether the GIS is discharged by comparing whether the acquisition channel has collected voltage signals, UHF signals or pulse currents. When it is determined that the GIS is discharged, the GIS discharge information is detected based on the voltage signals, UHF signals or pulse currents collected by the acquisition channel. The discharge information includes: discharge type, discharge amount and corona area.

[0051] Determine whether the GIS is discharging based on the collection results, specifically: if the solar-blind single-photon detector, UHF sensor and high-frequency current sensor all transmit signals, there must be discharge; if the solar-blind single-photon detector and UHF sensor have signals, but the high-frequency current sensor has no signal, there is discharge, the discharge is relatively weak and the optical path is not blocked; if the solar-blind single-photon detector and high-frequency current sensor have no signals, but the UHF sensor has a signal, there is discharge, the discharge is relatively weak and the optical path is blocked; if the solar-blind single-photon detector, high-frequency current sensor and UHF sensor all have no signals, there is no discharge.

[0052] The identification of the discharge type includes: according to the discharge identification basis, the PRPD spectrum analysis of the voltage signal, the UHF signal and the pulse current is performed to determine the discharge type. The discharge identification basis is obtained by pre-discharging with standard electrodes and system calibration. The diagnosis identification basis is shown in Table 1:

[0053] Table 1

[0054]

[0055] Detection of discharge volume and corona area includes:

[0056] The ultraviolet light signal photons first pass through the incident window and enter the photomultiplier tube of the solar-blind single-photon detector, where they are received by the photocathode and converted into electrons to form and output photocurrent I c , the processing device calculates the photocurrent I according to the following formula c , photocurrent I c That is the discharge amount:

[0057] I c =n·QE·q

[0058] Where n is the number of photons received by the cathode per unit time, QE is the quantum efficiency of the photomultiplier tube, and q is the electron charge;

[0059] Single photon detection of ultraviolet light signal pulses, the number of light pulses is the number of photons, and the relationship between the number of photons N and the relative corona area S is:

[0060] N=k∫∫η(λ)ds+n+M

[0061] Where k is the relative coefficient of the corona area, η(λ) is the photon radiation efficiency. When there is less ozone in the corona, η(λ) = 1, and it decreases with the increase of ozone concentration. n is the total number of dark current pulses in the test, and M is the amount of ultraviolet signal photons generated by the outer layer of the corona.

[0062] The present invention can realize single-photon detection and diagnosis of discharge inside GIS. The detection band is the solar-blind ultraviolet band, and can realize functions such as discharge type identification and discharge amount measurement.

[0063] The present invention highly integrates a solar-blind single-photon detector, an ultra-high frequency sensor, and a high-frequency current sensor. The three sensors can be directly connected to an acquisition card, and the acquisition card is used to realize synchronous acquisition of optical-electrical signals. The processing device automatically judges the existence of discharge, and can judge the optical path and electrical obstacle shielding between the discharge source and the sensor, which improves the reliability and sensitivity of detection compared with using only a single sensor. The processing device automatically calculates the PRPD spectrum and the time-domain pulse sequence spectrum of the optical-electrical signal pulse, and compares them with the standard discharge mode spectrum pre-calibrated by the system to obtain the closest discharge type, thereby realizing the recognition of the discharge type, and improving the accuracy and sensitivity of recognition compared with using only the ultra-high frequency detection method. The processing device counts the pulses of the optical pulse sequence, automatically calculates the corona area during discharge, and then combines the current pulse sequence to obtain the optical-current pulse sequence, and automatically calculates the discharge amount, which improves the sensitivity of the discharge amount calculation compared with using only the current pulse method.

Claims

1. A system for detecting discharge information inside GIS, characterized in that: The system comprises: A solar-blind single-photon detector is used to detect whether the internal discharge of the GIS generates an ultraviolet light signal. When the internal discharge of the GIS generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the internal discharge of the GIS. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card; The UHF sensor is used to detect whether the internal discharge of the GIS generates a UHF signal. When the internal discharge of the GIS generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card; High-frequency current sensor is used to detect whether the internal discharge of GIS generates pulse current. When the internal discharge of GIS generates pulse current, the high-frequency current sensor receives the pulse current generated by the internal discharge of GIS and transmits it to the acquisition card; An acquisition card having multiple acquisition channels, each of which is provided with a trigger level. When the amplitude of a voltage signal, a UHF signal or a pulse current received by any channel is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to synchronously acquire the voltage signal, the UHF signal and the pulse current through multiple channels; and A processing device is used to determine whether there is discharge inside the GIS by comparing whether the acquisition channel has collected a voltage signal, a UHF signal or a pulse current, and when it is determined that there is discharge inside the GIS, detect the discharge information inside the GIS according to the voltage signal, the UHF signal or the pulse current collected by the acquisition channel; The discharge information includes: discharge type, discharge amount and corona area; The acquisition card can be set to perform synchronous acquisition of multiple acquisition channels after a specific channel is triggered; The specific channels include: voltage signal trigger channel, ultra-high frequency signal trigger channel and pulse current signal trigger channel; The processing device identifies the GIS discharge type by drawing the time-domain pulse sequence spectrum and phase spectrum of the voltage signal, UHF signal or pulse current collected by the collection channel and comparing them with the standard discharge spectrum; The processing device calculates the discharge corona area by counting the number of photons during the discharge period, and calculates the discharge amount in combination with the current pulse signal.

2. A method for detecting internal discharge information of a GIS using the system for detecting internal discharge information of a GIS as claimed in claim 1, characterized in that: The method comprises: The solar-blind single-photon detector detects whether the GIS discharge generates an ultraviolet light signal. When the GIS discharge generates an ultraviolet light signal, the solar-blind single-photon detector receives the ultraviolet light signal with a solar-blind band of 260nm to 280nm generated by the GIS discharge. The ultraviolet light signal with a solar-blind band of 260nm to 280nm is converted into a voltage signal by the solar-blind single-photon detector and transmitted to the acquisition card. The UHF sensor detects whether the GIS discharge generates a UHF signal. When the GIS discharge generates a UHF signal, the UHF sensor receives the UHF signal and transmits it to the acquisition card. The high-frequency current sensor detects whether the GIS discharge generates pulse current. When the GIS discharge generates pulse current, the high-frequency current sensor receives the pulse current generated by the GIS discharge and transmits it to the acquisition card; When the amplitude of the voltage signal, UHF signal or pulse current received by any channel of the acquisition card is greater than the trigger amplitude of the trigger level, the acquisition card turns on the acquisition channel to synchronously acquire the voltage signal, UHF signal and pulse current through multiple channels; The processing device determines whether the GIS is discharged by comparing whether the acquisition channel has collected voltage signals, ultra-high frequency signals or pulse currents. When it is determined that the GIS is discharged, the GIS discharge information is detected based on the voltage signals, ultra-high frequency signals or pulse currents collected by the acquisition channel.

3. The method according to claim 2, characterized in that The discharge information includes: discharge type, discharge amount and corona area.

4. The method according to claim 2, characterized in that: The determination of whether the GIS is discharging is specifically as follows: if the solar-blind single-photon detector, the UHF sensor and the high-frequency current sensor all transmit signals, there must be discharge; if the solar-blind single-photon detector and the UHF sensor have signals, and the high-frequency current sensor has no signal, there is discharge, the discharge is relatively weak and the optical path is not blocked; if the solar-blind single-photon detector and the high-frequency current sensor have no signals, and the UHF sensor has a signal, there is discharge, the discharge is relatively weak and the optical path is blocked; if the solar-blind single-photon detector, the high-frequency current sensor and the UHF sensor all have no signals, there is no discharge.

5. The method according to claim 2, characterized in that: The identification of the discharge type in the discharge information includes: determining the discharge type after performing PRPD spectrum analysis of the voltage signal, the UHF signal and the pulse current according to the discharge identification basis, and the discharge identification basis is obtained by pre-discharging through standard electrodes and system calibration.

6. The method according to claim 2, characterized in that The discharge amount and corona area in the discharge detection information include: The ultraviolet light signal photons first pass through the incident window and enter the photomultiplier tube of the solar-blind single-photon detector, where they are received by the photocathode and converted into electrons to form and output a photocurrent I c , the processing device calculates the photocurrent I according to the following formula c , photocurrent I c That is the discharge amount: I c =n·QE·q Where n is the number of photons received by the cathode per unit time, QE is the quantum efficiency of the photomultiplier tube, and q is the electron charge; Single photon detection of ultraviolet light signal pulses, the number of light pulses is the number of photons, and the relationship between the number of photons N and the relative corona area S is: N=k∫∫η(λ)ds+n+M Where k is the relative coefficient of the corona area, η(λ) is the photon radiation efficiency. When there is less ozone in the corona, η(λ) = 1, and it decreases with the increase of ozone concentration. n is the total number of dark current pulses in the test, and M is the amount of ultraviolet signal photons generated by the outer layer of the corona.

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