Ok, found this in internet:
"Time dummy is a variable which equals 1 for a given year and 0 for all other years. It allows to control for time-specific fixed effects i.e. shocks which impact is restricted to a given time-period, affects or panel units and are not controlled by other explanatory variables. " source: https://www.researchgate.net/post/Is_anyone_familiar_with_Time_Trends_vs_Time_Dummies
And: " Year effects (more simply known as “year dummies”" Source: https://www.dartmouth.edu/~ethang/Lectures/Class17/Always%20Control%20for%20Year%20Effects%20in%20Panel%20Regressions.pdf
So i think the use of Time dummies, are Time effects! But if time effects are always fixed I dont know.