Which factory is good for online temperature monitoring system of oil immersed transformer winding

How to monitor the lifespan of oil immersed transformers

In the power industry equipment, oil immersed transformers play an important role in voltage and current conversion, as well as power transmission. Their performance directly affects the safe and stable operation of the entire power system. Analyzing, judging, and preventing transformer overheating faults has become a widely concerned issue for transformer manufacturers and relevant departments. There is currently no simple and unique end-of-life criterion that can quantitatively explain the remaining life of transformers.

Why do oil immersed transformers need temperature measurement

The performance of oil immersed transformers directly affects the safe and stable operation of the entire power system. Due to long-term operation at full load and the use of a fully enclosed structure, transformers often generate heat in various parts. In many cases, workers cannot measure certain narrow positions inside the transformer, especially the temperature on the winding that frequently heats. If the temperature of the transformer is too high during long-term operation, it will cause aging of the heating components, directly threatening the safety of the entire power grid. In large power transformers, transformer oil plays a crucial role in insulation, heat dissipation, and arc suppression, and is crucial for the safe operation of transformers. If the oil temperature of the transformer rises too high, it will lose its insulation effect, cause breakdown accidents, and even affect the service life of the transformer. Therefore, online monitoring and real-time control of transformer oil temperature are particularly important.

The Relationship between Life and Temperature of Oil Immersed Transformers

Power transformer is one of the core equipment in the operation of the power system. From the perspective of transformer insulation operation life, the transformer winding has a normal life (20 years) when the average annual temperature is 98 ℃; When the temperature exceeds 98 ℃, for every 6 ℃ increase, the lifespan of the transformer is reduced by half, which is the “6 degree” rule. The winding temperature of power transformers is closely related to their lifespan, so it is necessary to monitor the winding temperature online. Jednak, it is difficult to directly test the winding temperature. Generally, the winding temperature is calculated by testing the oil temperature of the transformer. This is because the average temperature of the transformer winding is 10 degrees higher than the oil temperature, so as long as the oil temperature of the transformer is tested, the temperature of the transformer winding can be determined. The operating life and load capacity of oil immersed power transformers are closely related to oil temperature. Transformers operating at high temperatures are prone to early failures due to overheating.

The operating temperature of transformers plays an important role in determining the operating status and insulation aging degree of transformers, and is an indicator that needs close attention in transformer operation and maintenance. Oil immersed transformers are the main equipment in transmission and transformation systems, and the winding temperature directly determines their service life. For transformers with graded insulation, increasing a certain temperature doubles the aging rate of insulation and reduces the working life of the transformer by half.

How to monitor transformer oil temperature

Obecnie, some in China use the top oil temperature of transformers as the switching signal to ensure the safe operation of transformers, and use the top oil temperature as the judgment basis for transformer monitoring devices to ensure the safe operation of transformers by monitoring the top oil temperature. Jednak, this method has many shortcomings. This is because the top oil temperature of large capacity transformers lags significantly behind the winding oil temperature. When the transformer load increases rapidly, due to the speed of heat transfer response, it takes several hours for the top oil temperature of the transformer to reflect the changes in winding conditions. Obviously, using the top oil temperature of the transformer as the switching signal to ensure the safe operation of the transformer cannot timely and effectively protect the safe and reliable operation of the transformer. The temperature of the transformer winding determines the service life of the transformer. For transformers with AA insulation, the insulation operating life is generally believed to follow the six degree rule: a normal life is obtained when the annual average temperature is 98 ℃. For every 6 ℃ increase in the annual average temperature, the aging rate of the transformer insulation doubles, and the service life of the transformer decreases by half. Therefore, the hottest temperature of the transformer winding is the determining factor for the safe, economical operation, and service life of the transformer.

What are the transformer oil temperature gauges available

The current temperature measurement methods for transformer windings in power equipment mainly include thermal resistance temperature measurement, thermoelectric coupling temperature measurement, oil temperature meter combined with calculation current method temperature measurement, and infrared temperature measurement. Jednak, the winding is in a special environment of high voltage, high temperature, and high magnetic field, and both thermal resistance and thermoelectric coupling need to use metal wires to transmit signals, which will cause electromagnetic interference to the environment. Metal wires are prone to aging and short circuits when they are in oil for a long time. Infrared temperature sensors cannot be installed in transformers and can only measure the surface temperature of transformers. The measurement results are affected by environmental temperature. The indirect measurement method using oil temperature meters has the disadvantage of large errors and cannot be directly measured. Therefore, it is currently unable to effectively measure the temperature of transformer windings.

Fiber optic online temperature measurement system for oil immersed transformers

Obecnie, in the field of transformers in China, the method of using point type optical fiber to measure the temperature of transformer windings has gradually been recognized. The fiber optic winding transformer temperature measurement device can monitor the hot spot position of the transformer oil flow in real-time under arbitrary changes, timely detect faults and safety hazards, and improve the reliability of power transformer operation. The transformer winding temperature measurement device can achieve online safety monitoring of winding temperature, without being affected by strong electromagnetic interference inside the transformer, and has high measurement accuracy, solving the problem of ineffective measurement of internal winding temperature in transformers.