How to measure temperature for dry-type rectifier transformers

Faseroptischer Temperatursensor, Intelligentes Überwachungssystem, Verteilter Glasfaserhersteller in China

The rail transit system, including subways, large railways, etc., requires specialized transformers, including traction transformers, rectifier transformers, etc. The dry-type phase-shifting rectifier transformer is used in conjunction with a high-voltage frequency converter. Currently, large capacity products in China mostly adopt a secondary multiple electromagnetic wire parallel winding method. As the capacity of the transformer increases, the number of parallel wires also increases to meet the temperature rise and loss requirements of the transformer. As the capacity of the transformer increases, the number of wires that need to be connected in parallel will also continue to increase. Due to differences in inductance and heat conduction between parallel wires, the current of the parallel wire phase will have a greater difference as the number of parallel wires increases, resulting in an imbalance in the temperature rise of the transformer. There are overheated areas in the transformer, which affect its service life and output capacity.

Why do rectifier transformers need to be cooled down and cooled down

During operation, the heating situation is severe, and the losses of the rectifier transformer used for electrolysis can reach 120kw. The losses are all converted from electrical energy into thermal energy and dissipated into the surrounding environment in the form of heat. The summer temperature is particularly high, and a large amount of heat is directly discharged, which will affect the surrounding environment. In addition, the high temperature of the rectifier transformer affects its service life, so cooling treatment is needed. During the operation of high-voltage rectifier transformers, a large amount of heat is generated. If the heat is not discharged in time, it will cause the internal components of the transformer to burn out, which is prone to faults and seriously affects the service life of the transformer; Usually, transformers use cooling methods such as fans and ventilation holes. If the ventilation channels are not set properly, resulting in low heat exchange efficiency, it cannot meet the cooling needs of high-voltage rectifier transformers. Especially under long-term operating conditions, high-voltage rectifier transformers are prone to faults, seriously affecting the service life of transformers.

Temperature monitoring of rectifier transformers

With the development of the power system towards ultra-high voltage and large capacity, in order to ensure the safe and stable operation of high-voltage electrical equipment, equipment condition monitoring is particularly important. Equipment temperature is one of the important parameters that reflect the operation status of equipment, so online monitoring of equipment temperature is of great significance. The dry-type phase-shifting rectifier transformer is used in conjunction with a high-voltage frequency converter, and the temperature rise control and cooling system control of the dry-type phase-shifting rectifier transformer coil are key controls to ensure the safe, reliable and continuous operation of the transformer. How to timely, accurately, and truly collect transformer temperature data, and then control the cooling system, is the key to the safe and reliable operation of the entire high-voltage frequency converter system. At present, the temperature control tube structure of dry-type phase-shifting rectifier transformers has basically not taken into account the impact of high-voltage electromagnetic fields on the sensitivity, authenticity, and timeliness of temperature control probe temperature measurement element data acquisition. There is an urgent need to design a new dry-type phase-shifting rectifier transformer to overcome the aforementioned shortcomings of existing dry-type phase-shifting rectifier transformers. Due to the high voltage of the phase-shifting rectifier transformer, the 6KV power frequency withstand voltage is 20KV, and the 10KV power frequency withstand voltage is 28KV. The traditional platinum resistance for temperature measurement cannot meet the withstand voltage requirements. The platinum resistance used for temperature measurement cannot be embedded in the coil and must be protected to prevent voltage breakdown. Thermal imaging or infrared thermometers cannot meet the accuracy requirements for temperature measurement. Deshalb, in response to the existing temperature measurement problems mentioned above, FJINNO provides a phase-shifting rectifier transformer winding fluorescent fiber optic temperature measurement device, which can effectively solve the technical problem of temperature measurement not meeting voltage resistance.

Fiber optic online monitoring device for rectifier transformers

The fluorescent fiber optic temperature measurement system for rectifier transformer winding can directly, real-time, and accurately measure the hot spot temperature of the winding, achieving comprehensive monitoring of the internal of the rectifier transformer and a wide temperature measurement range. In addition to accurate and reliable temperature measurement performance, there are also excellent anti EMI/RFI (electromagnetic interference/radio frequency interference) characteristics, high-voltage insulation, and anti-interference performance. The fluorescence fiber optic temperature measurement system consists of a temperature sensing fiber optic probe, a transmission fiber optic, and a fiber optic demodulator. The system has the characteristics of direct, online, real-time, and accurate measurement of winding hot spot temperature, and can achieve real-time and accurate monitoring of hot spot temperature during dynamic load operation.