Question { 3977 }

why we maintain 50hz ,220volts,20Amp,ratings fixed every
where in india,,electricity

Answer

in india we've got the more resources for producing
electricity. and also if we use the 50hz,220v the losses
will be less and we can save more power.

but in case of USA, they're using 60hz frequency as the
resources are very less for power production. and they cant
mind for the losses.

Question { Siemens, 11967 }

what is use of substation? Any book on how to instal or
construction of substations?

Answer

An electrical substation is a subsidiary station of an
electricity generation, transmission and distribution
system where voltage is transformed from high to low or the
reverse using transformers.

construction is explained in the books of john D Mc Donald.