This paper investigates electromagnetic shielding design and performance optimization for converter transformer monitoring devices to address their reliability issues in complex electromagnetic environments. A shielding enclosure structure mounted on the printed circuit board(PCB) of the monitoring device was designed

and the shielding performance of different enclosure materials

namely tinplate

brass

nickel silver

and stainless steel

was comparatively evaluated through no-load and load tests on a converter transformer. The experimental results show that

when tinplate is used as the shielding material

the signal-to-noise ratio(SNR) of the tank vibration signal acquired by the monitoring device will be increased by 12 dB compared with the unshielded configuration under converter transformer no-load and load operating conditions. This improvement is attributed to the alloy characteristics of tinplate

which combines high magnetic permeability and electrical conductivity

thereby enabling a magnetoelectric coupled shielding mechanism capable of simultaneously suppressing low-frequency magnetic fields and electric-field interference energy. Finally

a comparative test platform for the vibration monitoring system was established. The test results indicate that

compared with a reference device without dedicated electromagnetic shielding design

the self-developed device exhibits significantly improved electromagnetic interference immunity and can meet the requirements of online condition monitoring under the complex operating conditions of converter stations. The research results can provide a reliable solution for the engineering application of intelligent converter transformer monitoring systems in strong electromagnetic environments.