A relay that changed the power industry
spectrum.ieee.org
spectrum.ieee.org
I wonder how much it has changed since then. My former boss is still working on that project AFAIK, I should reach out to him…
I think most of us on HN think of Ethernet/Wifi/networking when we think of "IEEE", but there are whole other aspects/fields of EE that generally don't enter our consciousness regularly: the power systems work of this article is just one of them.
> SEL OT SDN technology solves some significant cybersecurity problems,” he says, “and frankly, it makes me feel comfortable for the first time with using Ethernet in a substation.
and this... party on dude!
> “I bought [ Protective Relays: Their Theory and Practice.] on the Thursday before classes began and read it over the weekend,” he says. “I couldn’t put it down. I was hooked.
https://selinc.com/api/download/138271/
It also clarifies what is meant by an 'energy packet':
> "Simply stated: “Energy packets are precise measurements of energy exchanges, independent of system frequency and phase angles, and are computed and communicated at a fixed rate, with a common time reference” [5].
> "Power analysis software integrates 1,000 samples of 1 μs data into a 1 ms energy packet [5] [6]. The analysis calculates joules (watt seconds) of energy packets exchanged every 1 ms. For example, a 1-watt load consumes 1 millijoule of energy within a 1 ms period. Energy packets are calculated in the SI unit joules (J). Joules are converted into watthours (Wh) by a time-scaled 3,600 seconds per hour where 1 Wh equals 3,600 J."
There's a call for you on line 1, someone calling himself Albert A. Stone wants to talk to you about this idea of a common time reference...
Imagine if sources could verify the link before sending each energy packet: no more electrocutions, electrical fires or damaged equipment. Imagine if in a domestic situation each energy packet was below the threshold that could damage a person? Electrical installations could become inherently safe, also meaning no need for specialist installers.
I get your point about universal time, EM waves and relativity. It doesn't stop data networks though, as packets include synchronisation, effectively establishing a local time for each link.
It's fascinating thinking about the analogies between data networks and power networks. What would synchronisation look like for an energy packet? What would a buffer look like, in case packets have to be multiplexed? What are the implications of being unable to copy energy packets? What is an energy packet? So many interesting questions.
What effect would "turning the hose on an d off" have on efficiency?
I don't think we have the answers (yet), but I think there will be benefits if we can find the answers. For example, we could truly leave the current generator/consumer model behind: just like the web enabled everyone to become a publisher, everyone could become a generator in their own right. No doubt we will then be talking about the Goolalisation of the energy network, where a theoretically distributed system becomes dominated by a small number of monopolies and people talk about how it's not worth running your own generator since Powersoft refuses to accept energy packets from smaller generators.
Most definitely not. You want to limit is as much as possible, as the reactive power (the "bounce back") still goes thru the resistance of the wire, generating losses. In fact big consumers often get charged when their power factor (the amount of energy "received" vs bounced back) is below a certain value.
Taking a system carefully designed to maximize power transmission across the country, and only sending power in bursts seems rather an odd design choice. You'd need to beef up all the transmission lines and transmission gear by a few orders of magnitude in current and/or voltage to make something like that possible. I'm not sure there's enough steel, aluminum, copper and insulators available to make that happen.
How would you store gigajoule "packets" of energy?
In theory, you could just send higher frequency AC or pulsed DC signal thru the wire (to get to the "one pulse is not all that dangerous" level), and with a bunch of ADCs discover every anomaly VERY quickly. But, now you're pouring high frequency signal into huge antenna, which means you probably need to change cabling to be twisted pair and recabling house is HUGE issue. And you have higher losses which means you'd realistically have to have power converter in every house for it as you couldn't transfer power at long ranges if it ran on several kHz
> Imagine if sources could verify the link before sending each energy packet: no more electrocutions, electrical fires or damaged equipment. Imagine if in a domestic situation each energy packet was below the threshold that could damage a person? Electrical installations could become inherently safe, also meaning no need for specialist installers.
If we assume sending device and receiving device both communicate how big energy packet would be and fail safe if it isn't, then sure, any interruption would be detected quickly, but it does nothing for cases where end device after the "power interface" has problems.
Also at least in US there is like 400 electrocution deaths per year, with only 20% from actual wiring [1], so it is a fight entirely not worth fighting, for residential at least.
Where I think it could be interesting is in high reliability equipment, where for example you might have power supply shared between a bunch of subsystems and you don't want failure of one component to cause brownout of whole thing. Sure, fuses do that but they are not exactly very elastic and don't send the signal about nature of the failure upstream.
A "power bus", where on top of delivering power subsystems can signal failure condition, or get signals (like "switch into power save mode, battery is low") might be interesting but if USB-PD is any indication it is FAR easier to make it into overengineered mess..
- [1] https://www.nickleelectrical.com/electrical-safety-statistic...
Over time SEL ended up taking over the market though.
The relays control actual power flow on the grid indirectly, using devices like breakers, tap changers, etc.
This article is talking about the digitalisation of relays, which basically means microprocessors or adapting industrial PLCs to do the same basic functions as the electromechanical relays but better (smaller, less maintenance, advanced features like fault localisation, remote control, etc.).
Interestingly, some power grids have resisted digitalisation out of concern that new electronics will have unknown fault characteristics that could lead to blackouts. Take this in contrast to railway signalling, which has if anything a more severe fault condition (would you rather be in a train crash or a blackout!) yet digital signalling was enthusiastically adopted by almost all systems.