Study on the triggering stability of laser diodes in LTT valve-RPU boards

In high-voltage direct current transmission systems, the RPU board in LTT valves emits light-controlled signals via laser diodes to drive the operation of light-controlled thyristors in valve base electronics (VBEs). However, its testing process faces dual challenges of dynamic response accuracy and biosafety. Addressing signal distortion in traditional contact based measurements and hazards from near-infrared laser radiation, this paper focuses on optimizing the trigger stability of laser diodes in reverse recovery protection units. By establishing a “optical-electrical-optical” collaborative monitoring architecture, this study investigates the mechanisms affecting RPU protection timeliness and proposes a noncontact optical-electrical joint testing system. The feasibility of this system is validated through an experimental platform for monitoring pulse stability in laser diode triggering. This research provides theoretical support and engineering solutions for enhancing the reliability of high-voltage DC converter valves.