We can build the substation up to 33Kv level in a room.Reason behind this is the sufficient clerence is provided in a panel.
We don't have isolators and earth switch in indoor substation as the no sufficient place. But in indoor substation also have some interlocks. Once the breaker was in close position we cannot rack-out that.After tripping that breaker only we can rack-out just same as isolator breaker interlock in outdoor substation.
in order to discharge the cable or bus bar we have to rack-in the cable earthing trolley and discharge as like earth switch as in case of outdoor substation.In outdoor substations we are mostly using SF6 circuit breakers but for indoor we are using mostly vacuum and air circuit breakers as low voltage levels.
The control voltage we are using for protection was dc voltage as we can store easily and protect the system under no power due to fault. Another important use is in case of AC transmission there is more voltage drop due to inductance and capacitance and resistance, but in DC we have only resistance drop so we can provide sufficient voltage to operate trip coils.
The control voltage we are using for protection was dc voltage as we can store easily and protect the system under no power due to fault. Another important use is in case of AC transmission there is more voltage drop due to inductance and capacitance and resistance, but in DC we have only resistance drop so we can provide sufficient voltage to operate trip coils.
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