5V,1Amp,DC supply

 This might be a good reference design to take a lookg at:

http://www.powerint.com/sites/default/files/PDFFiles/rdr201.pdf

You can optimize this reference design for high-line input only and can probably shave some cost/size off some of the components by doing so.

I'm not sure what you're asking about with your comment on inductive loads.  Can you please elaborate?

Regards,

The Traveler

Thanks for the suggestion. Inductive load is like switching ON and OFF of an electromagnetic contactor provided for switching ON and OFF of street Lighting. The controller has a small cube relay of 6VDC with NO  contact of 7Amp rating. This small relay gets ON OFF command through microcontroller at preset time and this further gives ON-OFF command to Three phase power contactor of contact ratng 40 amp,415V. This power contactor switches ON and OFF the street lighting. Since power contactor coil is an electro magnet of 240V,50 rating it produed transients  in the power supply line for a very short duration during closing and opening of the contactor. Since power supply to controller is also connect to the line this transients caused resetting of the mictrocontroller. I tried to resolve the problem by proving a Zero cross detector circuit so that the contactor could open and close at zero crossing only to eleminate/reduce the transient high voltage but could not get much help.

Regards

 I thought I had replied already but I guess my comment was absorbed by the inter-tubes.

This missing information I didnt get in your original post was that you're driving a relay coil.  Yes, you will *deifnitely* want to  use a coil EMI supression technique of some sort.  The zero crossing solution you've employed will help on the load side of the relay but will not do much if anything on the coil side of the relay.

If you do a quick internet search for "relay coil emi supression techniques" you will find multiple papers and tech articles on the different methods of coil EMI supression.

Some of these methods are:

-free wheeling diodes

-free wheeling diodes with series zener

-single resisters

-RC snubbers

-TVS

-MOV

As you can see, there are multiple techniques and it would be wise to employ at least one of them.  For example, the inductive kick on some relays I use (12V 400mW coils) could easily send the coil voltage at turn-off up to 100-200 volts.  This can damage capacitors, ICs, etc.  It can also cause problems with conducted and radiated EMI in your application.  

I hope this helps.  IF you need further assistance, let me know.

Regards,

The Traveler