Can the transformer oil chromatography online monitoring system identify different types of internal defects, such as overheating, partial discharge, and arcing?
Publish Time: 2025-09-10
In power systems, transformers are core equipment for energy conversion and transmission, and their operating status is directly related to the safety and stability of the entire power grid. However, due to long-term exposure to high voltages, high currents, and complex electromagnetic stresses, various latent defects such as overheating, partial discharge, and arcing may gradually develop within the transformer. If these faults are not detected in a timely manner, they can easily develop into serious accidents, causing equipment damage or even widespread power outages. Traditional periodic sampling and testing methods are limited by long cycles and high lag time. However, modern transformer oil chromatography online monitoring systems enable intelligent identification and early warning of different types of internal defects by continuously analyzing the composition and changing trends of dissolved gases in the insulating oil.
During normal operation, the insulating oil and solid insulation materials of the transformer are in a stable state, and the amount of gas generated is extremely small. However, when internal abnormalities occur, high temperatures or strong electric fields accelerate the decomposition of the insulating medium, generating specific types of flammable gases. Different types of faults, due to differences in energy density, temperature levels, and mechanisms, produce unique gas compositions. The online monitoring system is based on this principle. High-precision sensors capture real-time concentration changes of gases such as hydrogen, methane, ethane, ethylene, acetylene, carbon monoxide, and carbon dioxide in the oil. Combined with intelligent diagnostic algorithms, it performs pattern recognition to determine the nature of the fault.
When an overheating fault occurs within a transformer, caused by poor conductor connections, multiple core grounding points, or eddy current losses, the local temperature gradually rises, leading to thermal decomposition of the insulating oil. This fault typically produces methane and ethylene as the primary products. As the temperature rises, the gas concentration slowly increases, with the ethylene component gradually increasing in proportion. By tracking the generation rate and proportion of these gases, the system can accurately identify overheating areas and assess their severity, providing sufficient time for operation and maintenance personnel to intervene.
Low-energy discharge phenomena such as partial discharge (PD) are typically caused by air gaps, impurities, or concentrated electric fields within the insulation. The energy released during the discharge is insufficient to trigger a violent reaction, but it is sufficient to dissociate oil molecules, primarily producing hydrogen and a small amount of methane. Due to the intermittent and cumulative nature of the discharge, the gas growth is relatively gradual, but hydrogen always dominates. By capturing the sustained upward trend of hydrogen and its ratio characteristics with other gases, the online monitoring system can effectively distinguish partial discharge from other types of faults, avoiding misdiagnosis.
Arc discharge is a serious, high-energy, high-temperature fault typically caused by a winding short circuit, interturn breakdown, or floating potential discharge. This fault releases enormous energy in a very short period of time, causing the insulating oil to rapidly decompose and produce large amounts of acetylene, accompanied by high concentrations of hydrogen and ethylene. A sudden surge in acetylene is often the most obvious sign of arc discharge. If the system detects a rapid increase in acetylene concentration or a sudden spike in acetylene concentration, it immediately triggers a high-level alarm, indicating a potentially critical fault and requiring an emergency shutdown and inspection.
In addition to identifying single faults, the online monitoring system also offers comprehensive diagnostic capabilities. By integrating analytical models such as the absolute concentration, relative content, growth slope, and three-ratio method of multiple gases, the system can distinguish complex faults, such as those in which overheating precedes discharge. Furthermore, the visual display of data trend graphs allows technicians to intuitively understand the fault's development process and determine whether it is stable, developing, or deteriorating.
Furthermore, the system supports remote access and multi-site centralized management, allowing operations and maintenance personnel to view the status of each transformer in real time from the control center, achieving unified cross-regional monitoring. The long-term accumulation of historical data also provides a scientific basis for equipment health assessment, lifespan prediction, and maintenance strategy optimization.
In summary, the transformer oil chromatography online monitoring system is more than just a gas detection device; it is also an intelligent diagnostic platform with "perception-analysis-judgment" capabilities. Through precise analysis of dissolved gases, it transforms invisible internal hazards into readable data signals, effectively identifying typical defects such as overheating, partial discharge, and arcing, establishing a solid early warning defense line for the safe operation of the power system.
