Abstract: The grid connection demarcation switch serves as the demarcation point between the property rights of the photovoltaic station and the power supply company, and is also a key node for dividing the scheduling scope. Therefore, it is necessary to calculate the protection setting reasonably to ensure that it can be selectively automatically cut off in the event of a fault. This article takes the 10 kV distributed photovoltaic station in Guozhuanghu, Qianxi County as a case study to rigorously calculate the protection settings of the grid connected and collector lines of the photovoltaic station. This case study aims to provide reference and guidance for the calculation of protection settings for similar engineering projects.