Abstract: During long-term space missions, spacecraft can experience failures due to temperature fatigue aging, wear and tear, collisions with space debris, and leaks in sealing components. Therefore, welding equipment is required for in-space repairs of spacecraft. The welding equipment needs to be equipped with a −10 kV/1 kW power supply. The use of high-voltage high-power power supplies in orbit focuses on high-voltage insulation protection during operation and grounding design on spacecraft. This paper proposes and analyzes solutions for the reliability, safety, and grounding design of high-voltage high-power power supply equipment for space applications. The proposed solutions support the in-orbit application of welding equipment.