Research on High-angle operation Capability of Converter Valve Based on Thyristor Control Unit Optimization

Abstract

When the converter valve operates at a high angle, the voltage stress borne by the internal electrical components increases, the loss of the damping circuit increases, and the junction temperature of the thyristor increases. For the influence of the harmonic component of valve voltage on thyristor energy extraction at a high angle, the thyristor control unit energy extraction circuit was optimized. Aiming at several typical high-angle operation conditions of ± 800kV hybrid cascade converter valve, the high-angle operation capability of the converter valve was studied and tested. Firstly, the electrical stress of the converter valve under different operating conditions of high angle was analyzed. Secondly, based on the engineering parameters of the Baihetan-Jiangsu UHVDC project, the operating parameters of the converter valve at high angles were calculated, and the most severe stress of the converter valve at high angles was extracted. Finally, based on the principle of the converter valve synthetic test circuit, the high-angle test parameters of the converter valve were calculated, and the high-angle operation test was carried out. The theoretical analysis and test results show that the electrical stress of the converter valve under high-angle working conditions is slightly higher than the rated operating condition, and the converter valve can withstand this stress, which can meet the requirements of long-term operation at a high angle.