From latest description of Mr. Hamid, it seems that PILOT WIRE PROTECTION is used. In that case my earlier messages are not relevant to this particular case. PW protection is a diffeential protection and the setting recommended as per manual of the relay is to be used. This is because relevant currents are passed through an impedence and the voltage drop on this impedence is used to activate the relay.In any case if there is a tripping on no load, increase setting as done alone is the solution. ————————- N P NAIR,C Eng,MIET,FIE(I),SrMIEEE.