My Question is
1.Basically we have HT motors the winding is made up of copper and it is provided with a copper lug for termination with the power cable.The Power cable we are using is of aluminium 400 sqmm for a 6.6kv motor.(We can terminate the aluminium cable with copper lug and connect with the motor copper lug or we can keep aluminium lug to cable and by providing a bimetallic washer we can connect with the copper lug of motor)Please suggest us the right approach

I would prefer copper lug, with bi-metallic crimping zone (Al compatible inside of the crimping tube).

Copper to Aluminium lugs are available. less risk for corrosion.