Oil-immersed transformer integrated condition monitoring device

• • Comprehensive multidimensional diagnosis: The core value of an integrated condition monitoring device is integrationDissolved gas in oil (DGA),Microwater and oil,Partial Discharge (PD),Fiber optic winding temperature measurement,Core ground current,Casing insulation,On-Load Tap Changers (OLTC)and more physical state parameters, through intelligent algorithms for data fusion and cross-validation, to achieve accurate and comprehensive assessment of the transformer health state.
  • Enabling Predictive Maintenance (PdM): The system revolutionizes transformer O&M from the traditional time-based periodic maintenance (TBM) model to predictive maintenance based on real-time equipment status. It aims to provide precise early warning and intervention before failures occur, minimizing unplanned downtime and improving grid reliability.

• • Deepen asset life management: Through continuous monitoring and quantitative assessment of the transformer's health index (Health Index), to provide objective and scientific data support for equipment overhaul, technical reform, life extension or decommissioning decision-making, is the key technical tool to achieve the optimization of the cost of the entire life cycle of power assets.

• Modular and Scalable Architecture: Modern monitoring devices are modular in design, allowing users to flexibly configure the subsystems they need to monitor according to the transformer's importance level and budget. From basic DGA and microwater monitoring to comprehensive fiber optic temperature measurement and OLTC monitoring, the system can be smoothly upgraded and interfaces are reserved for future function expansion.

Core Diagnostics and Analytics Subsystem

These subsystems focus on analyzing the chemical and physical signals generated by the insulation inside the transformer under electrical and thermal stresses and are the cornerstone of fault diagnosis.

Online Dissolved Gas Analysis in Oil (Online DGA) Module

In-line DGA unitconstituteTransformer TroubleshootingThe most decisive technology in the field. It enables the continuous monitoring of fault signature gases by non-invasively extracting oil samples from the main oil cycle and utilizing advanced photoacoustic spectroscopy (PAS) or non-dispersive infrared (NDIR) techniques.

Key monitoring gases and their significance

• Discharge fault gas:
  • Hydrogen (H₂). The primary product of corona or partial discharge (PD) is a sensitive indicator of the presence of weak discharge defects in the insulation system.
  • Acetylene (C₂H₂). The sole product of a high-energy arc discharge, its presence usually signals the presence of a severe, high-risk internal short circuit or breakdown fault.
• Superheated faulty gas:
  • Methane (CH₄) and ethane (C₂H₆). Produced mainly by overheating decomposition of insulating oil in the low to medium temperature (<300°C) region.
  • Ethylene (C₂H₄). Indicates the presence of a medium to high temperature (300°C - 700°C) overheat point, usually associated with a poor conductor connection or eddy current overheat.
• Solid insulation (cellulose) deteriorating gas:
  • Carbon monoxide (CO) and carbon dioxide (CO₂). It is the main product of the decomposition of insulating paper and cardboard under overheating conditions.The CO/CO₂ ratio is an important basis for determining whether solid insulation is involved or only oil overheating is involved.

DGA monitoring moduleProvides not only the instantaneous concentration value (ppm) of each gas, but more importantly analyzes itsGas Generation Rate, a rapidly increasing generation rate is a better predictor of the urgency of a failure than a static concentration value.

On-line monitoring module for micro-water and oil characterization

Moisture is what acceleratesTransformer insulation agingThe primary chemical factor in theOn-line monitor for micro water in oilis the basis for assessing the long-term health of the insulation system.

Difference between water activity (aw) and absolute moisture (ppm)

• Water activity (aw). A dimensionless parameter (0~1) that directly reflects the tendency of moisture to migrate from the oil to the solid insulation, and is a fundamental indicator for assessing the degree of moisture exposure of insulating paper.High-aw value(e.g., >0.4) is directly related to the risk of a "bubble effect" due to sudden load changes.
• Absolute moisture content (ppm). Indicates the mass ratio of water in the oil, the value of which is drastically affected by the temperature of the oil, and cannot be used independently to determine the degree of dryness of solid insulation, but can be used to assess the quality of the oil itself.

In addition, the more advancedOil quality online analyzerIt is also possible to integrate the control ofBreakdown voltage (BDV),Dielectric loss factor (tanδ)respond in singingacid valueThe on-line measurement provides data for a comprehensive assessment of the electrical properties and aging of the oil.

Critical Physical Condition and Safety Monitoring Subsystem

This type of subsystem is responsible for monitoring the transformer's macroscopic physical operating parameters, and is the first line of defense to ensure the safe and stable operation of the equipment.

Winding fluorescent fiber optic direct temperature measurement and oil temperature monitoring

Temperature is the most direct physical quantity that affects the life of a transformer. The use ofFluorescent fiber optic temperature measurement technologyIt is the most accurate and reliable means of monitoring winding temperatures.

• • Direct measurement of winding hot spots: commander-in-chief (military)Fluorescent Fiber Optic Temperature SensorsPre-embedded inside the winding during the manufacturing phase, the Hottest Spot Temperature (HST) of the winding is measured directly. Since the fiber optic itself is insulated and not subject to electromagnetic interference (EMI), the measurements are true and delay-free, far superior to conventional thermal modeling algorithms based on top oil temperature and load current.

• Oil temperature gradient monitoring: At the same time, temperature sensors are installed in the upper and lower parts of the transformer box to monitor in real-timeTop Oil Temperature (Top Oil Temperature)respond in singingBottom Oil Temperature (BOTTOM OIL TEMPERATURE). The temperature difference between the two reflects the cooling system's circulation efficiency and helps diagnose a clogged cooler or fan/oil pump failure.

Reservoir oil level and body pressure monitoring

• • Reservoir oil level monitoring: adoptionMagnetic Flip-Flop Level Meteror radar level meter to continuously monitor the level of insulating oil in the Conservator Tank. Abnormal decreases in oil level are usually indicative of an oil leak, while abnormal increases can be related to internal gas production or overloading.

• Body pressure monitoring and release valve status: The state of micro-positive pressure inside the tank is monitored by means of a pressure sensor. What's more, for thepressure relief valve(Pressure Relief Device)The operating status of the valves is monitored. As soon as the valves are actuated, which means that a serious and sudden fault has occurred inside the transformer (e.g. short-circuiting of the windings) and a large amount of gas has been generated, the system immediately issues an alarm of the highest level.

Auxiliary equipment and specialized monitoring extension subsystems

Large power transformers are complex structures and the condition of their auxiliary equipment is equally critical.

On-Load Tap-Changer (OLTC) Online Monitoring

On-Load Tap Changer (OLTC)It is the only mechanical component on the transformer that moves frequently and is a high failure point. Specialized monitoring of it is essential.

• Electrical and timing characteristics: Monitoring of the current waveform and action time sequence of the drive motor during tap changer switching. By comparing the standard waveforms, early defects such as mechanical jamming and poor contact contact can be diagnosed.
• Oil chamber status: Monitoring the oil temperature, micro-water and dissolved gases in the oil (especially C₂H₂) inside the separate oil chamber of the OLTC provides an effective early warning of ablation and insulation degradation of its internal contacts.
• Switch position and number of operations: The current tap position and cumulative number of operations are recorded and remotely transmitted to provide a basis for evaluating its mechanical life and developing a maintenance program.

Cooling system operation status monitoring

For forced oil circulation air-cooled or water-cooled transformers, the reliability of the cooling system directly affects its load capacity.

• Fan/fuel pump status: Each set of cooling fans and submersible oil pumps is monitored for start/stop status, operating current and accumulated runtime. Abnormal currents indicate motor failure and run times are used to assess life.

Specialized monitoring of high pressure casing (oil level/pressure)

Add physical condition monitoring to the electrical performance monitoring of the casing.

• Casing oil level monitoring: For oil-filled casing, cameras or sensors are configured through its own oil level window or pressure gauge to realize remote monitoring of oil level and prevent insulation accidents due to lack of oil.

Core and case vibration monitoring

• Online monitoring of iron core vibration: Highly sensitive vibration acceleration sensors are arranged on the walls of the box to monitor the vibration characteristics of the transformer at the industrial frequency and its octave. Abnormal changes in the vibration spectrum may indicate mechanical structural problems such as loose cores, deformed windings or loose fasteners.

SF₆ gas density monitoring (for GIS outlet bushings)

• GIS casing SF₆ monitoring: For transformer-GIS connecting bushings insulated with SF₆ gas, the density, pressure and temperature of the SF₆ gas inside must be monitored online. A decrease in density can seriously threaten insulation safety, and the system needs to provide real-time alarms and blocking signals.

Intelligent Diagnostics and Data Fusion Platform

The data collected by all the front-end sensors is finally pooled into theBackend Data Servertogether withIntelligent Diagnostic Platform. It's not just a simple listing of data, it's what lies at the heart of the system's intelligence.

Transformation from data to information

• Multidimensional data correlation analysis: The core algorithm of the diagnostic platform is capable of correlating data from different sources. For example, when the system simultaneously detects a UHF localized discharge signal, an increase in H₂ concentration in the DGA, and an abnormal CO/CO₂ ratio, it can determine with a high degree of confidence that the fault originated from an internal discharge involving solid insulation. Suchcross-validationThe capability greatly improves diagnostic accuracy.
• Health Index (HI) modeling: The platform uses a weighting algorithm to transform all the monitored parameters into a single, quantifiedTransformer Health Index(e.g., on a scale of 0-100.) HI provides O&M managers with an intuitive, macroscopic view of device status that facilitates horizontal comparisons and status sorting of groups of devices.
• Failure trend prediction: Based on historical data, using time series analysis, neural networks or machine learning models, the platform is able to predict future trends in key parameters (e.g., characteristic gas concentrations, dielectric loss values), thus predicting the time window in which failures are likely to occur, and supporting the development of forward-looking maintenance plans.

Transformer integrated condition monitoring deviceThe application of the power system asset management to digitalization, intelligent transformation of the inevitable trend, it will transform the transformer from a "black box" into a state of complete transparency, risk predictability, life can be managed intelligent assets.

To provide the most professional protection for your critical power assets and learn about customized online monitoring solutions for your transformers, contact our technical experts today for a free consultation. We will provide you with detailed technical solutions, product selection recommendations and return on investment analysis.