During long-term operation, the transformer oil chromatography online monitoring device may trigger false alarms due to oil circuit leakage, carrier gas pressure fluctuations, or sensor drift. It is recommended that the technical engineer first check whether the oil sample sampling port is sealed, then check whether the carrier gas cylinder pressure is below 0.2 MPa, and finally verify the detection unit with standard gas. If the value continues to deviate, the oil-gas separation module should be cleaned and recalibrated.
Record the carrier gas remaining amount, cold trap temperature, oil circulation flow rate, and communication status daily. The cold trap temperature should be kept within the storage and transportation limit range of -40°C to +80°C, but during operation it is usually set at -5°C to 5°C. When the oil circulation flow rate fluctuates by more than ±10%, the oil pump and pipeline should be checked. If communication is interrupted for more than 10 minutes, check the connection between the industrial control computer and the remote access software.
It is recommended to calibrate the detection unit once every 6 months with a standard mixed gas. Before calibration, confirm that the temperature control system is stable at 40°C ± 0.5°C. The calibration gas path needs to be connected independently to avoid interference from residual carrier gas. If the device is installed in a high-humidity environment, the cold trap maintenance cycle should be shortened to prevent water vapor condensation from affecting the separation effect of the chromatographic column.
When the concentration of characteristic gases such as acetylene and hydrogen suddenly increases, first rule out external interference: check whether the transformer has recently been oil-filled, oil-filtered, or subjected to welding operations. After confirming that there are no external factors, take an oil sample and send it to the laboratory for comparison. If the deviation between the online data and the laboratory exceeds 30%, check whether the oil-gas separation membrane is aged or the oil circuit is blocked. The three-ratio method results in the diagnostic software are for reference only, and the final conclusion shall be based on offline retesting.
If the device is shut down for more than one week, the oil circuit needs to be drained and purged with dry nitrogen to prevent oil sludge from solidifying. Before recommissioning, replace the carrier gas filter, check all sealing rings, and perform oil sample pretreatment in accordance with the relevant requirements of GB7597, GB/T7601, GB/T14542, and DL/T596. After power-on, run the self-test program first, and confirm that the communication of each unit is normal before connecting to the transformer oil circuit.
