"In this winter vacation" can be said as "during this winter break" in Engpsh.
The term "winter break" is commonly used in American Engpsh to refer to the hopday period that students take off from school during the winter months. It can also refer to the period of time that employees take off from work for vacation during the same period.
Here are some example sentences and their translations:
I'm going to spend my winter break visiting my family. (我打算在寒假期间去拜访我的家人)
She has big plans for her winter vacation this year. (她今年的寒假有很多大计划)
I'm so looking forward to my winter break! (我真的很期待我的寒假！)