CN-116242962-B - Gas marking self-calibration method and system of on-line monitoring device for dissolved gas in insulating oil

CN116242962BCN 116242962 BCN116242962 BCN 116242962BCN-116242962-B

Abstract

The invention discloses a gas marking self-calibration method and a system of an on-line monitoring device for dissolved gas in insulating oil, wherein the method comprises the following steps of continuously marking the gas under the normal condition of the pressure of the gas marking; determining the relative standard deviation of the gas component concentration or peak height/peak area under continuous gas calibration, if the relative standard deviation is not smaller than the set threshold, continuing to perform gas calibration until the relative standard deviation is smaller than the set threshold and the continuous calibration times do not exceed the maximum calibration times, if the relative standard deviation still does not meet the requirements when the maximum calibration times are reached, triggering calibration abnormality warning, acquiring the average concentration of the gas component or the average value of the peak height/peak area when the relative standard deviation meets the requirements, comparing the average concentration of the gas component or the average value of the peak height/peak area with the last calibration data and the first calibration data, and terminating the calibration flow, correcting the gas calibration coefficient or triggering calibration abnormality warning operation according to the comparison result. The periodic gas marking calibration of the monitoring device with different detection principles is realized, and the workload of operation and maintenance management is reduced.

Inventors

XU TING
QI QIUBO
QI GUODONG
ZHANG RUIQIANG
YU NAIHAI
ZHANG YONG
XIE LIANKE
CHEN YIMIN

Assignees

国网山东省电力公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20221118

Claims (8)

1. The standard gas self-calibration method of the on-line monitoring device for the dissolved gas in the insulating oil is characterized by comprising the following steps of: continuous gas calibration is carried out under the normal condition of the gas calibration pressure, and the single gas calibration process comprises the following steps: according to the gas chromatography detection principle, chromatographic preheating, baseline stabilization, standard gas purging, sample introduction, chromatographic sampling, spectrogram analysis and standard gas component retention time judgment are sequentially carried out; If the deviation between the retention time of the gas marking component and the first calibration exceeds a third threshold value, the retention time is abnormal and warning prompt is carried out, and the retention time of the gas marking component is modified to be the retention time of the current calibration gas marking component; Determining the relative standard deviation of the gas component concentration or peak height/peak area under continuous gas calibration, if the relative standard deviation is not smaller than a set threshold, continuing to perform gas calibration until the relative standard deviation is smaller than the set threshold and the continuous calibration times do not exceed the maximum calibration times; Acquiring the average concentration or peak height/peak area average value of the gas component when the relative standard deviation meets the requirement, comparing the average concentration or peak height/peak area average value with the last calibration data and the first calibration data, and stopping the calibration flow, correcting the gas calibration coefficient or triggering the calibration abnormality alarm according to the comparison result; The process of comparing the last calibration data with the first calibration data comprises: If the relative standard deviation of the first calibration data and the last calibration data is not greater than a fifth threshold value, the gas calibration coefficient is not modified when the relative standard deviation of the first calibration data and the last calibration data is not greater than a sixth threshold value, and the calibration process is terminated; if the relative standard deviation between the first calibration data and the last calibration data is between the fifth threshold value and the seventh threshold value, correcting the standard gas coefficient when the relative standard deviation between the first calibration data and the first calibration data is between the sixth threshold value and the eighth threshold value; And if the relative standard deviation of the calibration data and the previous calibration data is not smaller than the seventh threshold value, triggering a calibration abnormality alarm when the relative standard deviation of the calibration data and the first calibration data is not smaller than the eighth threshold value, and ending the flow.
2. The method for calibrating the gas marking self-calibration of the insulating oil dissolved gas on-line monitoring device according to claim 1, wherein the method is characterized by judging whether the gas marking pressure is normal, if the gas marking pressure is smaller than a first threshold value and smaller than a second threshold value which is smaller than the last gas marking pressure, the gas marking pressure is abnormal, an alarm prompt is triggered, the calibration process is terminated, and otherwise, continuous gas marking is carried out under the condition that the gas marking pressure is normal.
3. The method for calibrating the gas marking self-calibration of the insulating oil dissolved gas on-line monitoring device according to claim 1, wherein according to a gas chromatography detection principle, firstly, chromatographic preheating is carried out, then whether a base line is stable or not is judged, and if the base line is not stable and the preheating is not overtime, the chromatographic preheating is continued until the base line is stable; if the preheating is overtime, whether the base line is stable or not, the preheating is overtime and alarming is carried out, and the calibration flow is terminated; And if the baseline is stable and the preheating is not overtime, carrying out standard gas purging, sample injection, chromatographic sampling, spectrogram analysis and standard gas component retention time judgment.
4. The method for calibrating a gas-calibrating on-line monitoring device for dissolved gas in insulating oil according to claim 1, wherein the modified gas-calibrating coefficient is a first calibrated concentration or peak height/peak area divided by a current calibrated concentration or peak height/peak area.
5. The standard gas self-calibration system of the insulating oil dissolved gas on-line monitoring device adopts the standard gas self-calibration method of the insulating oil dissolved gas on-line monitoring device according to any one of claims 1 to 4, and is characterized by comprising an air source module, an air path module and a control module; the gas source module comprises a standard gas steel cylinder, a pressure sensor and a gas pressure reducing valve, wherein the standard gas steel cylinder is connected with the gas pressure reducing valve, and the pressure sensor is arranged between the standard gas steel cylinder and the gas pressure reducing valve; the gas circuit module comprises a vent pipe and a gas marking valve, the gas pressure reducing valve is connected with a detection module of the dissolved gas on-line monitoring device through the vent pipe, and the gas marking valve is arranged on the vent pipe; the control module is used for controlling the conduction of the gas marking valve so as to conduct the gas source module and the detection module when the gas marking is carried out.
6. The system for calibrating the on-line monitoring device for the dissolved gas in the insulating oil according to claim 5, wherein the standard gas cylinder is filled with standard mixed gas, and the standard mixed gas is mixed with methane, ethylene, ethane, acetylene, hydrogen, carbon monoxide and carbon dioxide gas by taking nitrogen as a base gas.
7. The system for calibrating the online monitoring device for the dissolved gas in the insulating oil according to claim 6, wherein the concentration range of each gas comprises 30-200 mu L/L of methane, 30-200 mu L/L of ethylene, 30-200 mu L/L of ethane, 10-100 mu L/L of acetylene, 200-1000 mu L/L of hydrogen, 300-2500 mu L/L of carbon monoxide and 1000-4000 mu L/L of carbon dioxide.
8. The system for calibrating the on-line monitoring device for the dissolved gas in the insulating oil according to claim 5, wherein the detection module is further connected with the degassing module through a vent pipe, and the control module controls the gas calibrating valve to be in a state that the degassing module is communicated with the detection module when the oil sample is detected.

Description

Gas marking self-calibration method and system of on-line monitoring device for dissolved gas in insulating oil Technical Field The invention relates to the technical field of automatic on-line monitoring of power equipment, in particular to a standard gas self-calibration method and system of an on-line monitoring device for dissolved gas in insulating oil. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. The on-line monitoring device for the dissolved gas in the insulating oil can rapidly identify the faults of the oil-filled electrical equipment in real time and alarm, so that the on-line monitoring device is widely applied to the places such as transformer substations, convertor stations, power plants and the like. In the running process of the device, due to the ageing, abnormality or damage of parts, improper operation and maintenance management and other reasons, the measurement error is increased, the stability is reduced, and the on-line monitoring effect is lost. At present, reference oil samples are required to be used for detecting the devices, the number of installed sites is very large, the detection is time-consuming and labor-consuming, the detection period of 1-2 years is difficult to complete the detection of all the devices, and about half of the detection results often do not meet the standard requirements. Therefore, it is obvious that the device detection by means of preparing the reference oil sample cannot meet the requirement, and it is necessary to shorten the period to detect the device and find out the main problems of the device in time. The core component of the device is a detection module no matter the gas chromatography or the photoacoustic spectrum detection principle, and is also the component which is most easy to age or damage, and problems can be found in time and defects can be eliminated rapidly by adopting the regular calibration of the standard gas. However, the existing standard gas calibration technology is difficult to be compatible due to the differences between components and systems of various factories of the device and lacks a standard operation and maintenance strategy, so that the implementation is not yet started at present. Disclosure of Invention In order to solve the problems, the invention provides a gas marking self-calibration method and a system of an on-line monitoring device for dissolved gas in insulating oil, which realize periodic automatic gas marking of the on-line monitoring device for the dissolved gas in the insulating oil with different detection principles, automatically find out the problems of abnormality and aging of a detection module of the device, impure gas production of a carrier gas pump and the like, and effectively reduce the workload of operation and maintenance management. In order to achieve the above purpose, the present invention adopts the following technical scheme: In a first aspect, the invention provides a method for calibrating a gas marking self-calibration device of an on-line monitoring device for dissolved gas in insulating oil, comprising the following steps: Continuous gas calibration is carried out under the normal condition of the gas calibration pressure; Determining the relative standard deviation of the gas component concentration or peak height/peak area under continuous gas calibration, if the relative standard deviation is not smaller than a set threshold, continuing to perform gas calibration until the relative standard deviation is smaller than the set threshold and the continuous calibration times do not exceed the maximum calibration times; And obtaining the average concentration or peak height/peak area average value of the gas component when the relative standard deviation meets the requirement, comparing the average concentration or peak height/peak area average value with the last calibration data and the first calibration data, and stopping the calibration flow, correcting the gas calibration coefficient or triggering the calibration abnormality alarm according to the comparison result. As an alternative implementation mode, whether the standard pressure is normal is judged, if the standard pressure is smaller than a first threshold value and smaller than a second threshold value which is smaller than the last standard pressure, the standard pressure is abnormal, an alarm prompt is triggered, the standard flow is stopped, and otherwise, continuous standard pressure calibration is carried out under the condition that the standard pressure is normal. As an alternative embodiment, the single labeling process includes: according to the gas chromatography detection principle, chromatographic preheating, baseline stabilization, standard gas purging, sample introduction, chromatographic sampling, spectrogram analysis and standard gas component retention time judgment are sequentially carrie