how the electricity coming in rainy day .

Are you referring to lightning?

Since this is not my area of expertise, I searched Google under the key words "lightning" to get these possible sources:

http://en.wikipedia.org/wiki/Lightning_discharge#Discharge
http://science.howstuffworks.com/lightning.htm
http://environment.nationalgeographic.com/environment/natural-disasters/lightning-profile.html

I hope this helps. If not, repost with your question in clearer terms. Thanks for asking.