Spatial Electric Field Characteristics in Large-scale Oil-pressboard Insulation Structure under Impulse Voltage

The reliable manufacture of the oil-pressboard insulation system of converter transformer largely depends on numerical calculation and electric field measurement under the simple equivalent model. It lacks electric field measurement verification under large-scale complex structure. The electric field characteristics in the large-scale valve-side outlet device model of the ± 800kV converter transformer under impulse voltage with different voltage amplitudes and different wavefront times was obtained in this paper. The actual measurement results show that the value of field intensity in three transformer oil-spacing will increase with the rise of the applied voltage amplitude. The peak value of field intensity in transformer oil-spacing would decrease with the rise of wavefront time. In the same oil-spacing, the closer the measuring point to the electrode of applied voltage, the bigger the peak value of field intensity, but the maximum deviation is about 3.61%, which may be due to the little accumulation of interface charge under lightning impulse voltage.