How to monitor transformer oil temperature, oil level, internal pressure, 2025, complete guide

Faseroptischer Temperatursensor, Intelligentes Überwachungssystem, Verteilter Glasfaserhersteller in China

Basic principle of transformer oil temperature, oil level, internal pressure three in one monitoring device
The three in one monitoring device for transformer oil temperature, oil level, and internal pressure is mainly achieved through different sensor technologies to monitor oil temperature, oil level, and internal pressure.

Principle of oil temperature monitoring:
Temperature sensors are usually used to measure oil temperature. Zum Beispiel, some sensors based on the principle of thermal resistance or thermocouple are installed in suitable positions in transformer oil. The resistance value of a thermal resistance sensor (such as a platinum resistor) changes with temperature, and based on this characteristic, the corresponding oil temperature value can be obtained by measuring the resistance value. Thermocouples utilize the thermoelectric effect of two different metals, which generates an electromotive force when there is a temperature difference between the two ends, reflecting the temperature level. This method can obtain real-time and accurate temperature information of transformer oil, in order to detect abnormal increases or decreases in oil temperature in a timely manner, as changes in oil temperature may indicate issues such as the load condition, heat dissipation effect, or internal faults of the transformer.
Oil level monitoring principle: There are multiple ways to implement oil level monitoring. A common method is based on the principle of differential pressure. Zum Beispiel, pressure sensors are installed at different height positions on the oil pillow (oil storage tank) to calculate the oil level height by measuring the pressure difference generated by the oil column. When the oil level changes, the height of the oil column changes, resulting in a change in pressure difference, which can accurately determine the level of the oil. Außerdem, some devices also use liquid level sensors to detect the distance between the oil level and the sensor through principles such as ultrasound and capacitance, thereby obtaining the oil level situation. Accurate oil level monitoring helps ensure that there is sufficient insulation oil inside the transformer, preventing problems such as decreased insulation performance caused by low oil level or abnormal oil tank pressure caused by high oil level.

Principle of internal pressure monitoring:
For monitoring internal pressure, pressure sensors are often used. Fiber optic pressure sensors have a unique design structure when applied to internal pressure measurement of oil immersed transformers. Zum Beispiel, some fiber optic grating pressure sensors encapsulate the fiber optic grating in a special structure and use internal sensitizing polymers to affect the optical properties of the fiber optic grating (such as wavelength changes) under pressure, thereby measuring pressure. In the design, the complex multi physics environment inside the transformer, such as long-term high-temperature oil immersed electromagnetic environment, should be considered to ensure the accuracy and stability of the sensor. When a fault occurs inside the transformer (such as arc discharge), it will cause a sharp change in the pressure inside the oil tank. By monitoring the pressure in real time, this abnormal situation can be detected in a timely manner to avoid more serious accidents.

Application of Transformer Oil Temperature, Oil Level, Internal Pressure Three in One Monitoring Device in Power System

Application in oil immersed transformers:
Oil immersed transformers are widely used equipment in power systems, and the three in one monitoring device plays a crucial role in them. During operation, changes in oil temperature directly affect the performance and lifespan of the transformer. Excessive oil temperature may accelerate the aging of transformer oil and reduce insulation performance. The three in one monitoring device can monitor the oil temperature in real time and issue an alarm in a timely manner when the oil temperature exceeds the normal range, so that operation and maintenance personnel can take measures such as adjusting the load or checking the cooling system. Accurate monitoring of oil level can ensure the normal insulation and heat dissipation environment inside the transformer. If the oil level is too low, it may expose some windings to the air, reduce insulation effectiveness, and increase the risk of faults; If the oil level is too high, it may cause abnormal pressure in the fuel tank. Internal pressure monitoring can quickly detect sudden changes in pressure when faults occur inside the transformer (such as short circuits causing arcing and a sharp rise in oil temperature, resulting in high pressure due to oil vaporization), preventing serious accidents such as oil tank rupture and ensuring the safe operation of the transformer.

Application in modular substations:
The modular substation integrates various power equipment such as transformers and switchgear. The application of the three in one monitoring device helps to comprehensively monitor the operating status of the entire substation. Due to the relatively compact space of the combined substation and the significant mutual influence between equipment, the stability of transformer oil temperature, oil level, and internal pressure is particularly important for the safe and reliable operation of the entire substation. Through this monitoring device, data can be transmitted in real-time to the monitoring system of the substation, achieving remote monitoring and centralized management. Operation and maintenance personnel can timely identify potential problems with transformers in modular substations based on monitoring data, carry out maintenance and handling in advance, reduce power outage time, improve power supply reliability, and also help optimize the operation and management of substations, improve equipment utilization and service life.

Advantages of the three in one monitoring device for transformer oil temperature, oil level, and internal pressure

Comprehensive monitoring and early warning:
This three in one monitoring device can simultaneously monitor oil temperature, oil level, and internal pressure. Compared to single function monitoring devices, it provides more comprehensive information on the operational status of transformers. Zum Beispiel, monitoring the oil temperature alone may not explain whether the increase in oil temperature is due to an increase in load or an internal fault causing a decrease in oil level and poor heat dissipation. By comprehensively monitoring the three parameters, the operating condition of the transformer can be more accurately determined. Once any parameter is abnormal, a warning signal can be issued in a timely manner to remind the operation and maintenance personnel to take measures. This helps to detect problems early on, avoid further deterioration of the fault, reduce the risk of transformer damage, and thus improve the safety and reliability of the power system.

Save costs and space:
In the power system, the cost of equipment and installation space are important factors to consider. Using a three in one monitoring device instead of three separate oil temperature, oil level, and pressure monitoring devices can reduce equipment procurement costs. Meanwhile, as only one device needs to be installed, the space and wiring workload required for installation are reduced. Zum Beispiel, in the construction or renovation process of substations, reducing the number of equipment and installation space can lower construction costs and make it easier to layout and maintain other equipment within limited space. Außerdem, the maintenance cost of integrated devices during operation is relatively low, as only one device needs to be maintained and managed, reducing the workload and maintenance difficulty of operation and maintenance personnel.

Improve operational efficiency:
Real time and accurate monitoring data helps optimize the operation and management of transformers. By long-term monitoring and data analysis of oil temperature, oil level, and internal pressure, the operating rules of transformers under different loads, environmental temperatures, and other conditions can be understood. Operations personnel can adjust the load of transformers reasonably based on these data, develop scientific maintenance plans, such as determining the optimal operating mode of the cooling system according to the oil temperature change pattern, and arranging oil replenishment and other operations in advance according to the oil level change. This can improve the operational efficiency of transformers, extend their service life, reduce energy consumption, and thus enhance the overall economic efficiency of the power system.

The product of FJINNO Electronic Technology Co., Ltd.: The company’s independently developed oil temperature oil level oil pressure three in one monitoring device is designed according to the online monitoring requirements of intelligent distribution transformers, combined substations, and related technical standards. It has the advantages of high security, niedrige Kosten, good real-time performance, convenient installation, and easy maintenance. The device can achieve precise monitoring of transformer oil temperature oil level oil pressure and upload it to the intelligent fusion terminal in the substation area through RS-485, which can meet the basic requirements of power system for monitoring the operation status of transformers. Zum Beispiel, in the monitoring of some small substations or distribution transformers, due to their low cost and convenient installation, they can be easily deployed on a large scale to achieve effective monitoring of transformers.

Maintenance and upkeep of the three in one monitoring device for transformer oil temperature, oil level, internal pressure

Regularly check sensors: Sensors are the core components of the three in one monitoring device, and regularly checking the performance of sensors is an important part of maintenance work. For temperature sensors, to check their measurement accuracy, they can be calibrated by comparing them with standard thermometers. Zum Beispiel, every certain period of time (such as six months or one year), a calibrated high-precision thermometer is used to measure the temperature of transformer oil, while reading the temperature value of the monitoring device. If the deviation between the two exceeds the allowable range, the temperature sensor needs to be adjusted or replaced. For pressure sensors and oil level sensors, it is also necessary to check their measurement accuracy and stability. The pressure sensor can be calibrated using a standard pressure source, and the oil level sensor can compare the actual measured oil level (such as manually measuring the oil level) with the oil level displayed by the monitoring device. If a sensor malfunction or performance degradation is found, the sensor should be replaced in a timely manner to ensure the accuracy of monitoring data.

Cleaning and protection: The monitoring device may be affected by pollutants such as dust and oil during operation, so regular cleaning is necessary. Be careful to avoid damaging sensors and other components during cleaning. Zum Beispiel, a clean soft cloth can be used to gently wipe the housing and sensor surface of the device to remove dust and oil stains. Gleichzeitig, it is necessary to ensure that the protective measures of the device are intact, such as checking the sealing performance of the device to prevent rainwater, dust, etc. from entering the interior of the device. For monitoring devices installed on outdoor transformers, good protection can extend their service life and reduce failures caused by environmental factors. If aging or damage to the seals is found, they should be replaced promptly to ensure the protective effect of the device.

Data backup and analysis: The monitoring device will continuously collect data such as oil temperature, oil level, and internal pressure, which are very important for analyzing the operating status of the transformer. Deshalb, regular data backups should be conducted to prevent data loss. Data can be stored on local servers or in the cloud, and a data management system can be established to facilitate querying and analysis of the data. By analyzing historical data, potential issues with transformer operation can be identified, such as long-term trends in oil temperature, fluctuations in oil level, and abnormal pressure conditions. Based on these analysis results, maintenance plans can be developed in advance, optimizing the operation and management of transformers, and improving their reliability and safety.