Answer to Question 1
A net meter is an electrical power meter that has the ability to measure the power going through it in either direction. This type of meter is important for use on solar energy systems that are connected to the grid, so that it can measure the electrical power the solar system sends to the grid, as well as major electrical power the consumer is using from the grid.
Answer to Question 2
The substation is a group of transformers used to step up the voltage at the generating station where voltage is put into the system. At the end where voltage is used, a substation is used to drop voltage to a usable level where it is moved around town. The voltage may come through one more substation at an industrial site.