Electromagnetic protection technology of data acquisition system in UHVDC environment

Wide-frequency online measurement system of corona current installed in the ultra high-voltage direct current(UHVDC) test lines in China works in UHVDC electromagnetic environment. In order to ensure that the system works stably and obtains valid data, we discussed the shielding effect of corona current online measurement system in UHVDC environment on the basis of the electromagnetic shielding theory and modeling in ANSYS. Simulative results indicated that the system had shielding effectiveness of 73 dB at 100 MHz. The measurement system was applied in an actual project, and its setup was observed by ultraviolet imager. The photon number of the ultraviolet setup images was 0, meaning that no discharge appeared on the equipment surface. It is concluded that the proposed measurement system has an effective electromagnetic protection, and it can work normally and efficiently in UHVDC environment.