[Bookman]

110V DC certainly ought to narrow down the variables for consideration. Such Voltages were not just power stations but most substations, be they for transmission and distribution or even industrial substations.
We then must consider the use of DC which always referred to circuit breaker trip and close supplies which were maintained via the appropriate battery. The fact that such systems would function only under alarm/fault conditions meant they would rarely operate. This in turn would always leave doubt in the minds of those who wondered if they would operate when called upon and as such there is a circuit called “trip circuit supervision”.
The latter entailed the ability to insert a relay coil for alarm purposes in the trip circuit in a way that would not permit enough current to flow to trip the appropriate breaker or otherwise. One could also undertake this manually via a switch using an indication light on the same basis; ergo could this be such a device for a bank of 11 breakers.
11 lamps would suggest a switchboard incorporating 2 incoming circuits, 1 bus section circuit and 4 feeder circuits either side of the section.

I could of course be completely wrong!