Transformer Active Protection Method Based on Multi-Parameter Fusion

When an internal arc fault occurs in an oil-filled power transformer, a great amount of energy is released in a very short span of time. In this case, it is too difficult for relay protection device to act in time and block the arc fault development. Considering that the vast majority of transformer electrical faults have a certain development process, it is a good choice to cut off the transformer when the discharge develops into a slight arc fault. In this paper, the characteristics of high frequency pulse current (HFPC), ultrahigh frequency signal (UHF) and acoustic signal (AE) in the process of transformer discharge development are analyzed by means of test. It is found that with the increase of discharge quantities, HFPC discharge amplitude and UW discharge times increase, while AE main frequency component decreases. In addition, the three kinds of signals have clear time synchronization, which can be used to eliminate interference signals. Based on the above analysis, a new protection method for transformer based on the fusion of HFPC, UW and AE signals is proposed in this paper.