The stray current leaked from rail transit may invade the power supply system of the urban power grid and cause the DC bias of the transformer. In order to study the DC bias of the transformer caused by the dynamic stray current, it is necessary to carry out the field measurement and data analysis of the stray current. Based on the action mechanism of dynamic stray current on transformer DC bias, this paper uses a special open-coil type stray current sensor and an 8-channel vibration acceleration synchronous monitoring system to measure the stray current and the vibration acceleration of the transformer shell on-site. The numerical calculation of the DC bias current of the transformer caused by the stray current can measure the acceleration while measuring the stray current, so as to accurately calculate the neutral point of the transformer and the stray current of the outlet field. The analysis of the stray current data can effectively The effective spectral components of the stray current can be determined in a timely manner, which can provide reproducible basic data for the DC bias test of the transformer.

Stray current; field measurement; DC bias; transformer neutral point; vibration