Firstly

the technical parameters of the 550 kV net-side resin impregnated paper（RIP） bushings for converter transformer were determined by electric field analysis and main insulation analysis.In the development of the new RIP bushing

the faults of the existing bushings were fully considered

various bottom connection modes were adopted

the difficulties in such as capacitance winding and epoxy resin impregnation were overcome

and new techniques were employed.According to the determined technical parameters

new RIP bushing was developed.Its insulation length in oil was increased by about 200 mm to enhance the anti-flashover capability in oil and improve the axial insulation margin of the bushing.Meanwhile

the insulation thickness in bushing oil increased by about 15%

which increases the partial discharge inception voltage and the radial insulation margin of capacitor core.This RIP bushing successfully passed all type tests at one time

and completed the third-party check of electric field strength at the hoist seat

indicating it could ensure safe operation in power grid.The bushing was put into actual operation at Tianshan converter station on June 24

2019

and all operating indexes are normal.