4 ms·

Is this a control system for an electro-mechanical relay, or is the relay itself part of the innovation? I couldn't find info about that in the article.

philwelch 3y ago
The relay itself is digital rather than electro-mechanical. (I went to WSU and, like many Cougs, interned at SEL.)
- RobotToaster 3y ago
  Is there anything special about it? Or is the actual switching just done by a beefy IGBT?
  - p_l 3y ago
    Much faster detection of fault, including ability to detect and point to a fault happening at a distance from the relay.
    - philwelch 3y ago
      Yeah, the story I remember being told is that power companies originally didn’t want to replace their electromechanical relays so they installed the SEL boxes alongside them and used them as fault locators. Over time SEL ended up taking over the market though.
      - 31carmichael 3y ago
        They haven't completely taken over the market. The likes of Siemens, ABB, GE, etc. manufacture similar products. SEL is considered the best by many utility engineers.
        philwelch 3y ago
        From what I recall, SEL’s market share was high enough in the US that almost all of our growth was international.
- ginko 3y ago
  So it's a big solid state transistor rather than a relay?
  - philwelch 3y ago
    Man, I don’t know how electricity works, I was writing test scripts in Perl.
winrid 3y ago
It's sensors and a control system. The article is a bit misleading.
deleted 3y ago
[deleted]
bearbin 3y ago
For context, when power grid engineers talk about relays, they're not talking about physical switching of the electricity itself, but instead the control and monitoring system for the grid. Traditionally this was done using specialised electomechanical devices (like the common electronic relay, but with special functions/construction). 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.

philwelch 3y ago

The relay itself is digital rather than electro-mechanical. (I went to WSU and, like many Cougs, interned at SEL.)

RobotToaster 3y ago
Is there anything special about it? Or is the actual switching just done by a beefy IGBT?
- p_l 3y ago
  Much faster detection of fault, including ability to detect and point to a fault happening at a distance from the relay.
  - philwelch 3y ago
    Yeah, the story I remember being told is that power companies originally didn’t want to replace their electromechanical relays so they installed the SEL boxes alongside them and used them as fault locators. Over time SEL ended up taking over the market though.
    - 31carmichael 3y ago
      They haven't completely taken over the market. The likes of Siemens, ABB, GE, etc. manufacture similar products. SEL is considered the best by many utility engineers.
      - philwelch 3y ago
        From what I recall, SEL’s market share was high enough in the US that almost all of our growth was international.
ginko 3y ago
So it's a big solid state transistor rather than a relay?
- philwelch 3y ago
  Man, I don’t know how electricity works, I was writing test scripts in Perl.

winrid 3y ago

It's sensors and a control system. The article is a bit misleading.

deleted 3y ago

[deleted]

bearbin 3y ago

For context, when power grid engineers talk about relays, they're not talking about physical switching of the electricity itself, but instead the control and monitoring system for the grid. Traditionally this was done using specialised electomechanical devices (like the common electronic relay, but with special functions/construction). 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.