It is widely acknowledged that hydrogen will play a significant role in the transition to net zero carbon energy systems. Europe has recently recognized this potential, implementing new strategies to promote hydrogen through investment programs. However, as power grids transition to rely more heavily on power electronics, grid codes are expanding to impose more strict requirements, also for consumption facilities. This presents a challenge for developers, who must address significant variations in national grid codes for demand facilities across Europe, necessitating location-specific plant designs.

This paper presents a case study for a 300 MW PtX facility focusing on how two rectifier technologies — thyristor-based and IGBT-based rectifiers — differ in grid code compliance and overall system design. Requirements related to active and reactive power control, fault ride-through capability, harmonic distortion limits, and dynamic response during grid disturbances are examined, and their impact on system configuration and component selection is discussed. The assessment is based on power system simulations performed in DIgSILENT PowerFactory, covering steady-state, harmonic, and dynamic analyses.

Results show that thyristor-based rectifiers may require significantly larger passive filters to meet harmonic distortion limits if a 24-pulse or 48-pulse configuration is not employed. While multi-pulse configurations can substantially reduce harmonic distortion, they introduce operational constraints, as harmonic cancellation requires balanced loading across all rectifier units — a condition that cannot be guaranteed when individual stacks or 6-pulse rectifier units are taken out of service for maintenance. For fault ride-through compliance, thyristor-based rectifiers may have difficulties meeting fast post-fault active power recovery requirements (in the order of seconds) when voltage does not return to pre-fault levels, due to the inherently slow voltage control associated with on-load tap changers (OLTCs). However, thyristor-based solutions remain a viable option where grid codes allow slower dynamic responses, particularly when combined with static reactive power compensation to meet reactive power requirements. IGBT-based solutions, by contrast, achieve harmonic compliance with reduced filtering needs and more readily satisfy fault ride-through and reactive power requirements.

The study concludes that technology selection is strongly governed by the specific dynamic response requirements defined in the applicable grid code, highlighting the importance of early-stage grid code assessment in PtX project development.