How can MNS low-voltage drawer cabinet avoid short circuit fault? It can be seen from the slight difference of amplitude-frequency characteristics of each phase at the high voltage side that if the amplitude of the main frequency is relatively large, the harmonic test of no-load vibration characteristics of another 300MVA power supply shows that the power grid is often short-circuited due to lightning strikes, relay protection maloperation or refusal to operate, and the strong impact of the short-circuit current of the low-voltage switchgear may damage the transformer, so efforts should be made to improve the short-circuit withstand capacity of the transformer from all aspects.
The statistical results of short circuit accidents show that the insulation distance will change and the solid insulation will be damaged, leading to partial discharge. When lightning overvoltage is applied, inter-turn and cake breakdown may occur, resulting in sudden insulation accidents. Even under normal working voltage, the long-term effect of partial discharge may lead to insulation breakdown accidents. About 80% is caused by MNS low-voltage drawer cabinet, and only about 10% is caused by operation and maintenance.
In the process of maintenance, on the one hand, it is necessary to minimize short circuit faults and reduce the number of shocks; on the other hand, it is necessary to detect the winding deformation in time to prevent its occurrence of danger. The vibration characteristics of the high and low voltage sides are different, and the winding deformation test and diagnosis are actively carried out. Usually, after the manufacturer is impacted by the short-circuit fault current, the winding will have local deformation, which may leave serious hidden dangers even if it is not immediately damaged.
In the frequency domain, the amplitude of the vibration signal at the same position of the three-phase high-voltage side appears at the same frequency position, that is, the amplitude of the vibration signal at the high-voltage side is 400Hz. However, in the frequency domain, the amplitude of the vibration signal at the low-voltage side is 100Hz.
The amplitude of the fundamental frequency and each harmonic of the vibration signal at the same position of the high and low voltage sides is in the same order of magnitude, that is, the frequency domain characteristics are basically the same. The safe, economic, reliable operation and output of the transformer depend on its own manufacturing quality, operating environment and maintenance quality, which can effectively prevent sudden failures during operation and maintenance. Come to our website for more relevant content http://www.tongyuhengcheng.com Do consulting!