Delhi Metro has a wide underground network of about 45+ km. The underground catenary is fed through insulated cables that run through from the on-surface power substations.
Whenever there is a cable fault, the existing faulty cable has to be disconnected before the secondary source can be used to feed into the catenary. This usually takes anywhere from 1-3 hours.
We solved this challenge by mounting a load break switch on the roof of the tunnel right above the catenary. The cable terminated at the load break switch which then fed the catenary. In this new system, the load break switch can be operated through SCADA remotely and the faulty cable can be isolated from the catenary within a matter of seconds.