December 18th - Geekout time again. I nipped in to Shenstone in the morning to beat the storm and pick up a Christmas present. On my way, the wind blew me down Bullmoor Lane to Chesterfield, near Wall. On the bend near Raikes, there’s been an electricity pole for years that’s fascinated me. It has a really complicated arrangement of equipment mounted upon it, and it’s effectively in the middle of nowhere. I’ve always been interested in it’s purpose, so I resolved to find out.
After a fair bit of googling, it’s an ‘automatic recloser’, and a really high-tech piece of equipment with a simple purpose; it’s an 11,000V breaker, performing the same kind of job as the ones you get in a modern domestic fusebox.
It consists of the unit that switches on and off the supply - the big box at the top, which breaks the three phase supply voltage present on the lines above, and an electronic control unit called an ADVC, which detects when there’s a fault, such as overcurrent in the load. A small transformer sits high up to supply the ADVC.
The ADVC reads the signals in the line, like voltage and current, and should it detect a problem, it disconnects or ‘opens’ the recloser, breaking the supply. Since most faults with overhead lines like this clear themselves quickly (they may be weather, vegetation or vermin related, for instance), the ADVC monitors the disconnected line and automatically recloses - reconnecting the supply - automatically.
The system is monitored by complex electronics with a computerised controller, and can communicate by radio telemetry, hence the antenna; it even has batteries so it can keep working if it’s own supply is interrupted.
I’ve been meaning to find that out for years… you can read more here.
This project takes me to some strange places, sometimes…