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#WorkTweet - We're building 22 high-power EV charging sites, all over Australia, which is a big country. They're infrastructure for EV drivers, so they've gotta work. Some of the sites are pretty remote, so how do we make them resilient? This is a thread about Ted, our designer
The key to resilience is remote operation, not just of the chargers, but of the electrical system. Chargers have software faults and require resetting sometimes. Electrical gear will trip for electrical faults and other weirdness, often necessitating someone to drive 400km
So Ted's been working away in the background on a remote operation console. We'll have a *very accurate* energy meter on each site which can do volts and amps, pfft, but also power quality, transients and harmonics. Hundredth of a second monitoring.
Ted's stretched the legs on these meters by adding circuit breaker operation. So I can sit here at my laptop and reset a circuit breaker anywhere in Australia. This is pretty standard SCADA stuff to this point.
Now the fun stuff. Ted's been working on a way to switch the breakers to minimise inrush current. Inrush current is proportional to the *instantaneous* voltage when the switch closes. Close the switch when the voltage passes through zero, inrush is zero.
Ted's got a system that can close a circuit breaker, remotely, *at the point when voltage passes through zero on each phase*. The meter measures voltage in hundredth of a second increments. The system says "in 3 hundredths we need the breaker closed".
Ted's calculated *the time it takes for the signal to travel from the meter to the circuit breaker* and triggers the close *before it should happen*, then it happens right on time, and the bloody thing works. Blows my mind.
He's also programmed a system that if a breaker trips, the meter records 2s of grid data either side of the trip, compiles the lot into an email and sends an automatically generated fault report.
The future is quite awesome.
The future is quite awesome.
And one last little thing, which is becoming mainstream these days.
We have big three phase circuits for the chargers on our sites, plus a few little single phase circuits for lights and controls. Each of these single phase circuits has a Safety Switch, as per Standard
We have big three phase circuits for the chargers on our sites, plus a few little single phase circuits for lights and controls. Each of these single phase circuits has a Safety Switch, as per Standard
Safety Switch is an RCD, residual current device, and needs to be tested every 6 months. We've installed a system that performs this test remotely, records the outcome, and again compiles and emails the report.
Think about the efficiency of testing 22 sites, every 6 months, in half an hour, rather than... about a week? Drive to Gundagai, open the switchboard, push the button, record the test outcome. Repeat over 3000km. Every 6 months.
