Analysis of the interruption characteristics and power burden of the superconducting DC circuit breaker in the grid-connected LVDC system

Renewable energy sources such as wind power and Photovoltaic power have been steadily increasing in recent years thanks to policies related to the increase in renewable energy generation to respond to climate change. The microgrid has the advantage of maximizing the efficiency of renewable energy such as wind power, solar power, and geothermal power and reducing losses by minimizing power conversion facilities. However, if a fault occurs in the DC system or the connected facilities, the fault current does not pass the zero-point, making it difficult to interrupt and the fault area will expand. In this paper, we proposed a superconducting DC circuit breaker as an appropriate protection method. This method limits the fault current and allows the current to pass through the zero-point so that it can be interrupted stably. We modeled the Photovoltaic power generation, Boost converter, Power conditioning system, three-phase AC gird, and the resonant DC circuit breaker connected with a superconducting element using the PSCAD/EMTDC. After simulating a short circuit fault in the modeled schematic, the interruption characteristics and power burden of the superconducting DC circuit breaker were analyzed. As a result, the initial fault current was reduced by about 25.25 % due to the quench resistance of the superconducting element when a short circuit fault. Therefore, the resonant circuit breaker connected to the superconducting element performed a stable interrupting operation about 3.84 ms after the contacts were opened.