CN-122017069-A - Chromatographic detection system and detection method for analysis of dissolved gas in transformer oil

CN122017069ACN 122017069 ACN122017069 ACN 122017069ACN-122017069-A

Abstract

The invention provides a chromatographic detection system and a detection method for analysis of dissolved gas in transformer oil, wherein the system comprises an integrated electromagnetic valve type valve island module, an integrated constant-current separation module, a composite detection module, a blowback stabilizing base line module and a blowback gas circuit, wherein the integrated electromagnetic valve type valve island module is used for carrying out flow path switching and controlling a sample to enter the integrated constant-current separation module, the integrated constant-current separation module comprises an input module for constant-current sample, a first chromatographic column channel for separating first gas in the sample and a second chromatographic column channel for separating second gas in the sample, the composite detection module comprises a first catalytic combustion sensor arranged at an outlet of the first chromatographic column channel, an infrared optical sensor and a second catalytic combustion sensor which are connected in series and arranged at an outlet of the second chromatographic column channel, and the blowback stabilizing base line module is connected with the blowback gas circuit controlled by the integrated electromagnetic valve type valve island module and is used for blowback to clean residual components of a double chromatographic column. The invention is based on the integration of solenoid valve island control, double-column parallel separation and multi-sensor detection, and meets the high standard requirement of on-line monitoring of the state of the power equipment.

Inventors

WU XIN
GUO AIHONG
CHEN KEYOU
XIONG WEI
HAN XINGJUN

Assignees

上海思源光电有限公司

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (9)

1. The chromatographic detection system for analyzing the dissolved gas in the transformer oil is characterized by comprising an integrated electromagnetic valve type valve island module, an integrated constant-current separation module, a composite detection module and a back-flushing stable baseline module, wherein: the integrated electromagnetic valve type valve island module is used for switching flow paths and controlling a sample and carrier gas to enter the integrated constant-current separation module; The integrated constant-current separation module comprises an input module connected to a sample inlet of the integrated solenoid valve type valve island module and used for constant-current samples and a double-channel module used for separating the samples, wherein the double-channel module comprises a first chromatographic column channel used for separating first-class gases in the samples and a second chromatographic column channel used for separating second-class gases in the samples; the composite detection module comprises a first catalytic combustion sensor arranged at the outlet of the first chromatographic column channel, and an infrared optical sensor and a second catalytic combustion sensor which are connected in series and arranged at the outlet of the second chromatographic column channel; The back-blowing stable baseline module is connected with a back-blowing air circuit controlled by the integrated solenoid valve type valve island module and is used for back-blowing the first chromatographic column channel and the second chromatographic column channel to remove residual components.
2. The chromatographic detection system for analysis of dissolved gas in transformer oil according to claim 1, wherein the integrated solenoid valve type valve island module comprises a plurality of micro solenoid valves, the micro solenoid valves are integrated on a common flow path plate, and on-off time sequence of each micro solenoid valve is controlled by a programmable logic controller to realize flow path switching and back blowing gas path control.
3. The chromatography detection system for analysis of dissolved gas in transformer oil according to claim 1, wherein the input module for constant-current sample comprises a steady flow valve, a sample injection valve, a dosing ring and a front end output valve, wherein an outlet of the steady flow valve is connected with an inlet of the sample injection valve, an outlet of the sample injection valve is connected with an inlet of the dosing ring, and an outlet of the dosing ring is connected with an inlet of the front end output valve; The dual-channel module for separating the sample comprises a three-way diverter, a first chromatographic column and a second chromatographic column, wherein one inlet of the three-way diverter is connected with an outlet of the front end output valve, two outlets of the three-way diverter are respectively connected with the first chromatographic column and the second chromatographic column to form a first chromatographic column channel and a second chromatographic column channel, the first chromatographic column adopts a molecular sieve column or a carbon molecular sieve column and is specially used for separating first gases in the sample and comprises H 2 , CO and CH 4 , the second chromatographic column adopts a porous polymer filling column and is specially used for separating second gases in the sample and comprises CO 2 and C 2 hydrocarbon gases.
4. The chromatography detection system for analysis of dissolved gases in transformer oil according to claim 1, wherein the blowback stabilization baseline module is activated after outflow of target components of both columns, and blowback residues from outlets of both columns to vent line outlets, respectively.
5. The chromatography detection system for analysis of dissolved gas in transformer oil according to claim 4, wherein the blowback steady baseline module comprises a blowback switching valve, a galvanostat, a vent valve and a vent filter at an outlet end of constant pressure carrier gas, wherein an outlet of the blowback switching valve is connected to an inlet of the galvanostat, one outlet of the galvanostat is connected with an outlet of a first chromatographic column channel of the integrated galvanostat separation module, the other outlet of the galvanostat is connected with an outlet of a second chromatographic column channel of the integrated galvanostat separation module, an outlet of the vent valve is connected with an inlet of a dosing ring of the input module, an inlet of the vent valve is connected with the vent filter, the blowback switching valve is used for switching in of carrier gas, the vent valve is used for controlling outflow of blowback exhaust gas, and the vent filter is used for preventing foreign matters from entering the vent valve.
6. The chromatography detection system for analysis of dissolved gas in transformer oil according to claim 1, wherein the first catalytic combustion sensor is used for detecting a first gas and comprises H 2 , CO and CH 4 , wherein after the infrared optical sensor is connected in series with the second catalytic combustion sensor, a sample firstly detects CO 2 in a second gas through the infrared sensor, and then enters the second catalytic combustion sensor to detect C 2 hydrocarbon gas in the second gas.
7. The chromatography detection system for analysis of dissolved gases in transformer oil of any one of claims 1-6, further comprising: The precise temperature and pressure control module is used for controlling the temperature and pressure stability of each flow path.
8. The chromatography detection system for analysis of dissolved gas in transformer oil of claim 7, wherein the precision temperature and pressure control module comprises an independent temperature controlled dual zone column box and an electronic pressure controller, wherein: The double-zone column box is used for controlling the temperature of different working temperatures of the integrated constant-current separation module and the composite detection module, and controlling the temperature of different sections independently, so that low-boiling-point components and high-boiling-point components are eluted in respective optimal temperature windows; the electronic pressure controller is arranged at the output end of the constant pressure carrier gas inlet valve and is used for dynamically adjusting the pressure in real time, compensating the influence caused by temperature change and chromatographic column resistance change and realizing a constant pressure mode.
9. A chromatography detection method implemented using the chromatography detection system of any one of claims 1-8, comprising: The sample is controlled by an integrated electromagnetic valve type valve island module to enter two chromatographic columns of an integrated constant-current separation module at the same time and is divided into two paths; Detecting effluent after the first path of sample passes through the first chromatographic column by a first catalytic combustion sensor; Detecting the effluent of the second path of sample after passing through a second chromatographic column by an infrared optical sensor and a second catalytic combustion sensor in sequence; starting a back-blowing gas circuit after chromatographic column analysis is completed and corresponding target components flow out, and removing residues of two chromatographic columns; and processing the detection signal of the sensor to obtain a gas concentration result.

Description

Chromatographic detection system and detection method for analysis of dissolved gas in transformer oil Technical Field The invention relates to the technical field of power equipment state monitoring and gas chromatography, in particular to a chromatography detection system and a detection method for analysis of dissolved gas in transformer oil. Background Power transformers are critical devices in power grid systems, and early internal failures often manifest themselves as changes in the composition and concentration of dissolved gases in insulating oil, such as hydrogen, carbon monoxide, carbon dioxide, and various low carbon hydrocarbon gases. Therefore, the method has important significance in accurately, rapidly and stably analyzing the dissolved gas in the transformer oil by chromatography and guaranteeing the safety of the power grid. In the prior art, the conventional gas chromatography system adopts a mode of single-column separation or serial double-column combined rotary valve switching, and has the following problems: 1. The separation degree is insufficient, namely, the monochromatic spectrum column is difficult to realize complete separation of H 2、CO、CH4 and C 2 hydrocarbon gas in a short time, and particularly, the separation effect of H 2 and CO is not ideal, so that the accuracy of quantitative analysis is affected. 2. The analysis period is long, the analysis speed of the series column system is limited by the slowest flowing-out component on the whole flow path, and the requirement of on-line monitoring on quick response cannot be met. 3. Poor baseline stability, i.e. the residual strong retention component in the chromatographic column slowly flows out in the subsequent analysis, which leads to baseline drift and ghost peaks, and affects the identification and quantification of constant components. 4. The traditional rotary valve has the problems of large dead volume, low switching speed, easy abrasion and leakage and the like, and the environment temperature and pressure fluctuation easily cause the drift of retention time, so that the stability of the system is reduced. The search finds that: The Chinese patent application No. CN104198601A discloses a chromatographic column parallel analysis device and method, which comprises a sample injection pipe, wherein the sample injection pipe is respectively connected with a first sample injection valve interface V and a second sample injection valve interface I, an interface II of the first sample injection valve is connected with an inlet of a first chromatographic column, an interface VI is connected with an interface III after being connected with a quantitative pipe I in series, the interface IV is connected with an emptying valve, an interface I is connected with a carrier gas, an outlet of the first chromatographic column is connected with a first detector, an interface II of the second sample injection valve is connected with an interface V after being connected with a quantitative pipe II in series, the interface III is connected with the carrier gas, the interface IV is connected with an inlet of the second chromatographic column, the interface VI is connected with the emptying valve III, an outlet of the second chromatographic column is connected with an interface I of a four-way switching valve, the interface II is connected with the emptying valve IV, the interface III is connected with the carrier gas, and the interface IV is connected with the second detector. The technology is used for sampling once, two chromatographic columns are separated in parallel and are not interfered with each other, so that the peak broadening caused by the serial connection of multiple detectors can be prevented, and the test time can be greatly saved. However, the technology still has the following technical problems that dead volume space in a gas path is increased by three 4-way valves and double quantitative pipes, for the same amount of sample gas, effective sample injection amount is reduced, peak height and peak area signals are reduced, tiny unbalance at the front end of a sample inlet pipe can cause slight difference of carrier gas flow rates of two chromatographic columns, and in the temperature programming process, the difference can be amplified, so that baseline drift or double peaks can be possibly caused. The application of three 4-way valves, a double metering tube and double temperature control increases the cost, and has extremely high requirements on the consistency of double column temperature control. For the current oil chromatograph online monitoring product, two identical detectors are used, the consistency of response factors, sensitivity and baseline noise level is required to be ensured, otherwise, errors are introduced when the peak areas of the two chromatograms are directly compared. Therefore, there is a need in the art for a specific chromatographic detection device that can achieve high resolution, rapid analysis, hig