Abstract: Disclosed are a fire extinguishing system and method for an ultra-high voltage (UHV) converter station, and a UHV converter station. The fire extinguishing system includes a spray fire extinguishing system and a fire monitor-based fire extinguishing system, where the spray fire extinguishing system includes a first fire pipe and a spray pipe; the fire monitor-based fire extinguishing system includes a second fire pipe and a fire monitor; one fire monitor is disposed right above a firewall on both sides of each converter transformer in the UHV converter station, and each fire monitor is connected to one second fire pipe; a spray pipe is disposed on the firewall on both sides of each converter transformer; and the fire monitor corresponding to each converter transformer, and an outlet of the spray pipe connected to the first fire pipe corresponding to each converter transformer face the converter transformer.

Abstract: A multifunctional C4F7N/CO2 mixed gas preparation system is disclosed. The C4F7N heat exchanger is used to heat and vaporize C4F7N input through the C4F7N input port; the CO2 heat exchanger is used to heat and vaporize CO2 input through the CO2 input port; the C4F7N/CO2 mixing pipeline structure is used to mix the heated C4F7N and heated CO2, and the C4F7N/CO2 mixed gas output pipeline structure is used to output the C4F7N/CO2 mixed gas. The C4F7N/CO2 mixing pipeline structure comprises a C4F7N/CO2 dynamic gas preparation pipeline structure and a C4F7N/CO2 partial pressure mixing pipeline structure; the C4F7N/CO2 partial pressure mixing pipeline structure includes partial pressure mixing tanks for mixing the CO2 and the heated C4F7N of certain pressures; and a plurality of partial pressure mixing tanks are arranged in parallel. A multifunctional C4F7N/CO2 mixed gas preparation method is also disclosed.