Difference Between Stations

There is no difference.

True there is no difference b/w all these still for your clarity what people use by convention in india (As you r from India ,i think so ) is as follows:

First comes substation (transmission lines comes here from power plant ) or a bigger size substation . then if you are setting up some equipments (let say motors ) you have to take that into a switch yard having a DP structure ,CT,PT (you might have seen a giant cable coming and terminating here as 3 cables , sometimes with a outdoor transformer ).

Now this is terminated in HT panel (Switchgear /containing VCB/ACB/SF6 Breaker )

Now comes Feeder : Which says that you have to control /switch on/off your motor from here only without interrupting anything .That is a Motor Feeder .

There are differences between feeder, substation, switchgear and switchyard.

Here is what they are:

Feeder: Feeders are the incoming circuits to the substation and outgoing circuits from the substation. In a substation, there are one or more incoming feeders and one or more outgoing feeder.

Switchgear: It is the combination of the circuit breaker and its protection, control, metering system including the disconnector (isolator), CTs and PTs etc. In low or medium voltage system, the switchgear components are located in the same indoor panel, but in high voltage system, circuit breakers, CT and PT are located outdoor and the control, protection and metering system are located in indoor panel.

Substation: It is the overall system including the transformer, switchgears, bus bar and all other related equipment and systems.

Switchyard: It is switching station with incoming and outgoing feeders but without the transformer. It is a type of substation but incoming feeders and outgoing feeders are of same voltage level. Some times, the out door area of a substation where the circuit breakers are located are also called switchyard of the substation.

- MS