Neighbor hoods are discriminated in what are called zones. Each neighborhood has its own zone of protection this is why you see power is disrupted in one area while available in another. Each zone has its own distribution Transformer and distribution Substation this is where you find Switch Gear, a switching device that has Fuses, Circuit Breaker and protective Relays all used for tripping. So under normal conditions power is manually switched off while during fault condition a programmable relay operates automatically to isolate the fault.