CAESAR II is just allowing you to define up to 9 sets (vectors) of displacements.
Let's say your line is tied to a much larger header having multiple operating modes. Say case 1, the header goes +1" in the X direction. Case 2 it goes to -1" X and +1" Z. You can define D1 = {1,0,0,0,0,0}*, D2 = {-1,0,1,0,0,0}*. D1 is displacement vector 1, D2 = displacement vector 2 etc.
In your load case setup, you can even combine them too if you want.
*{DX, DY, DZ, RX, RY, RZ}