DS200FHVAG1A called High-voltage SCR gate interface board, it is combined with load-commutated inverters and static starter units.

This board serves three primary functions:

It receives low-voltage trigger pulses from the control system and safely transmits them to the high-voltage side via toroidal isolation transformers. While ensuring electrical isolation, it delivers sufficient drive current to each SCR, guaranteeing precise, timely turn-on in strict accordance with control commands; this achieves complete high-to-low voltage isolation, making it suitable for the high-voltage (kilovolt-level) operating conditions of gas turbine starting systems.

It continuously monitors the reverse voltage withstand status across the SCRs. When an SCR is turned off and subjected to high blocking voltage, an onboard status LED illuminates to facilitate visual inspection by operations and maintenance personnel. In the event of SCR breakdown, short-circuiting, or abnormal voltage withstand characteristics, the board immediately sends a fault signal to the main control FPGA board, triggering a system shutdown to protect the power module from burnout.

It acquires voltage readings from the LCI inverter's internal energy storage capacitors and battery units, feeding this status back to the Mark V gas turbine control system. It participates in system interlocking and protection during voltage anomalies—preventing over-voltage or under-voltage damage to the starting power supply and the gas turbine generator—while also monitoring the DC bus voltage to ensure it remains within the permissible range.