Power Query : Add 3 hours to each row of a table's column whose data type is datetime

I resolved it myself, by adding individual columns for Date and Time from DateTime column and then incrementing the Date by 1 day and Time by 3 hours as below
Transformation to Add 1 Day to the extracted Date column

#"Transform Date" = Table.TransformColumns(#"Extract Signed Time",{{"Signed_Date",each Date.AddDays(_,1),type date}})

Transformation to Add 3 hours to the extracted Time column

#"Transform Time" = Table.TransformColumns(#"Transform Date",{{"Signed_Time",each _ + #duration(0,3,0,0),type time}})

hope this helps others facing similar issue while connecting to a PostgreSQL db instance hosted on linux server.