Prediction of the Thyristor Failure Rate under Various Operating Conditions Due to Atmospheric Neutron Irradiation

Atmospheric neutron irradiation is a threat to the safe and stable operation of DC transmission systems. In this paper, the failure rate of 8.5 kV thyristors due to atmospheric neutron irradiation is predicted using the ±800 kV DC transmission system as an example. Firstly, the voltage stress applied to the thyristors in the converter valve of the Ultra-High Voltage Direct Current (UHVDC) transmission system under various operating conditions is calculated. Then, the failure rate due to atmospheric neutron irradiation is predicted by integrating the periodic voltage waveform and the neutron irradiation failure rate under different voltage stresses. This study is of great significance for the construction of the UHVDC transmission project and the protection of high-voltage power semiconductors against the irradiation effect.