一、 Industry background of transformer vibration status monitoring
A power transformer is a static high-voltage electrical equipment, and its internal windings and iron core vibrate under the action of an electromagnetic field. Current flows through the windings to generate electric force, causing vibration. The iron core undergoes magnetostriction and vibration under changes in excitation current. Internal vibrations can be transmitted to the exterior of the transformer oil tank shell. Vibration is a normal phenomenon during transformer operation, but in the event of overload or excitation faults, the transformer will produce abnormal vibrations such as increased amplitude and frequency. Severe abnormal vibrations can cause winding deformation, inter turn insulation wear, component heating, and loose iron core clamps inside the transformer. Monitoring the mechanical vibration of transformers during operation can promptly identify potential faults and improve the efficiency of operation and maintenance, as well as the quality of power supply. Therefore, it is of great significance to conduct live detection or online monitoring of the vibration of transformers during live operation.
二、 The purpose of monitoring the vibration status of transformers
At present, in China, only two conventional techniques are used to test the deformation of transformer windings during power outages: low-voltage short-circuit impedance method and frequency response analysis method. In practical applications, it has also been found that certain deformations are reflected in the frequency response method but not in the low-voltage short-circuit impedance. The sensitivity to different types of main transformers varies, making it difficult to accurately determine the degree of winding deformation. Both methods have their own advantages and disadvantages. Moreover, power outage maintenance cannot reproduce the faults during live operation, and the abnormal vibration phenomenon of the main transformer will disappear after power outage. Therefore, traditional power outage detection methods cannot achieve accurate monitoring and fault diagnosis of abnormal vibration during live operation of the main transformer. Only vibration monitoring and real-time spectrum analysis under live operation conditions of the main transformer can truly achieve abnormal vibration monitoring and fault diagnosis of the main transformer.
三、 Application of Transformer Vibration State Monitoring
Eight highly sensitive vibration acceleration sensors are evenly arranged at the 1/4 and 3/4 height positions of the oil tank closest to the transformer winding. The sensors are attached to the surface of the transformer using magnets (suction force>50N).
四、 The transformer vibration monitoring system involves Senther Technology sensors
1. The 310A-10-LF: 310A series product is an IEPE accelerometer used for industrial vibration measurement. Its characteristic is the use of ceramic crystals with a circular shear mode as the sensitive element, which has the ability to maintain stable output for a long time.
2. The 331A: 331A series product is a universal three-axis IEPE accelerometer for low-frequency vibration measurement. Its characteristic is the use of ceramic crystals with a circular shear mode as the sensitive element, which has the ability to maintain stable output for a long time.
3. The 531P: 531P series product is a PE accelerometer for vibration measurement, which is characterized by using a ceramic crystal with a circular shear mode as the sensitive element and has the characteristic of maintaining stable output for a long time.
The operation status of transformers requires vibration monitoring and real-time spectrum analysis to truly achieve abnormal vibration monitoring and fault diagnosis of the main transformer.
