New Low Loss Phase Control Thyristors for Medium Current UHVDC Transmission

The presented new generation of 8.5 kV class Phase Control Thyristors (PCTs) in package with 119 mm pole piece features reduced ON-state voltage VT through optimized wafer thickness, resistivity and cathode design. Additionally, dV/dt and tq ratings were improved as well in the whole range of VT/Qrr values relevant for HVDC and industrial applications. This device completes the new generation PCT platform of ABB, where PCTs with rating currents of 1.5, 3 and 6 kA give designers the necessary degrees of freedom for optimal valve design for HVDC & UHVDC transmission.