As the massive new energy coming into the grid, the large-scale new energy centralized access to switching station in many districts, the structure of double-circuit transmission lines on the same tower is adopted. There are zero sequence protection actions in operation and frequent trip accidents. This paper takes the actual fault of the power grid as an example. Based on the PSCAD software, the network frame sent by 220 kV double-circuit transmission lines on the same tower of large-scale new energy centralized access to switching station is modeled accurately. The electromagnetic transient simulation of fault recurrence is realized. The causes of trip accidents are analyzed in depth. The source of zero-sequence current is found. In addition, it innovatively compares and analyzes the zero sequence current of the power grid after the 220 kV open-close station is boosted to 500 kV power station. The solution of zero sequence protection fixed value and boost transformation is proposed. A good measure is proposed for the source and protection of zero-sequence current in power grid structure sent by new energy, which provides a feasible scheme for the design, operation and protection setting of power grid. This work is supported by National Key Research and Development Program of China (No. 2016YFB0900105).