The invention relates to a power 
transformer on-line monitoring device and method based on the transient 
oil pressure characteristics. The power 
transformer on-line monitoring device includes a transient 
oil pressure characteristic quantity measurement module, a 
signal conditioning and acquisition module and a digital 
processing analysis module, the transient 
oil pressure characteristic quantity measurement module is connected with the 
signal conditioning and acquisition module, the 
signal conditioning and acquisition module is connected with the digital 
processing analysis module, and a datastorage module, a man-
machine dialogue module and a data 
communication interface module are all connected with the digital 
processing analysis module. According to the power 
transformer on-line monitoring device and method based on the transient oil pressure characteristics, transient oil pressure characteristic information of a plurality of measuring points inside a 
transformer oil tank are obtained in real time, an operating oil pressure value representing the oil 
pressure range of a transformer is calculated, and by comparing with a preset 
overpressure threshold value and a quasi-
overpressure threshold value, whether abnormal 
overpressure of a measured transformer occurs or not is judged; and the device is independent of a power network, and has the advantages of simple composition, easy implementation, reliability and accuracy, and the like.