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    NYC power outage

    Anyone have any insider info on the NYC power outage?
    https://www.cbsnews.com/news/manhatt...es-2019-07-13/
    Ifyoucan'texplain itsimply youdon'tunderrstanditwellenough- Albert Einstein

    #2
    Originally posted by ATSman View Post
    Anyone have any insider info on the NYC power outage?
    https://www.cbsnews.com/news/manhatt...es-2019-07-13/
    Are your lights flickering?
    Tom
    TBLO

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      #3
      2019 no generators


      Sent from my iPhone using Tapatalk

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        #4
        The building I'm currently working is in that zone of black out. Wonder if the generator started.
        Rob

        Moderator

        All responses based on the 2014 NEC unless otherwise noted

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          #5
          At this point just that my office was in the dark until about midnight.

          https://www.nytimes.com/2019/07/14/n...on-edison.html
          Ron

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            #6
            190714-1945 EDT

            The reporting on this problem is interesting.

            It has been said that about 70,000 customers lost power. I am not in the power industry and have little knowledge about it. But searching for a few tidbits and knowing what my power consumption is I can make some assumptions.

            During a day I am in the range of 1 to 2 kW for a load. So assume these NYC customers are at 1 kW, then they represent a load of 70,000 kW or 70 MW. How big are large distribution transformers? Possibly 100 MVA or more. These apparently take 6 months to several years to make, and many may not be made in the US. Also very expensive, and many units could not be sitting as spares. Also they very heavy and difficult to transport.

            It seems that the outage occurred all at once. An all at once event, like the great eastern blackout, has to have some common point of origin. However, it might be something small that cascades to a big event.

            I doubt one large transformer failed. Power was restored too quickly.

            In one report mention was made that the fire department responded to transformer fires. Implies more than one transformer. Why would more than one transformer fail at about the same time, possibly at different locations?

            Another report mentioned a mechanical failure, that likely does not mean electrical.

            It is clear that the politicians are technically ignorant as are the reporters. Most of the reporting is of an emotional nature.

            Can some of the power people comment on their thoughts.

            .

            Comment


              #7
              Originally posted by gar View Post
              190714-1945 EDT

              The reporting on this problem is interesting.

              It has been said that about 70,000 customers lost power. I am not in the power industry and have little knowledge about it. But searching for a few tidbits and knowing what my power consumption is I can make some assumptions.

              During a day I am in the range of 1 to 2 kW for a load. So assume these NYC customers are at 1 kW, then they represent a load of 70,000 kW or 70 MW. How big are large distribution transformers? Possibly 100 MVA or more. These apparently take 6 months to several years to make, and many may not be made in the US. Also very expensive, and many units could not be sitting as spares. Also they very heavy and difficult to transport.

              It seems that the outage occurred all at once. An all at once event, like the great eastern blackout, has to have some common point of origin. However, it might be something small that cascades to a big event.

              I doubt one large transformer failed. Power was restored too quickly.

              In one report mention was made that the fire department responded to transformer fires. Implies more than one transformer. Why would more than one transformer fail at about the same time, possibly at different locations?

              Another report mentioned a mechanical failure, that likely does not mean electrical.

              It is clear that the politicians are technically ignorant as are the reporters. Most of the reporting is of an emotional nature.

              Can some of the power people comment on their thoughts.

              .
              I suspect it is the transformer that steps down to 208V.

              Comment


                #8
                190714-2202 EDT

                An added comment not related directly to the NYC problem.

                Our shop is getting a new (replacement) substation. This is about 1/2 mile away from the shop, and about 1 mile from Michigan Stadium.

                This substation is being built like a fortress, high walls and tall posts.

                My son told me that he saw a trailer bring in a new transformer to the substation. This is located on S. State Street. The transformer was large, the load was oversize, and the trailer had very many axles. The road had to be closed to thru traffic. I believe that a standard semi-trailer with one or two axles can carry 40,000 #. My guess is that this transformer was well over 100,000 # (50 tons). Not something you can move and install quickly.

                None of the news comments on this replacement substation indicate its power capability. We also are getting a new added large substation on the North Campus about 5 miles away. The North Campus will then be supplied by two substations to provide redundant power. The other substation is not the S. State location, nor is it the U of M Main Campus power plant.

                The U of M North Campus has a number of large backup generators, and a small gas fired power plant. I don't know the power requirement of North Campus, but power has to be supplied with little interruption. A lot of power in a small area.

                For a high power illustration note that at one time the Ford Rouge power plant had a capacity 345 MW. This supplied an area of about 1 x 1.5 miles.

                .
                Last edited by gar; 07-14-19, 10:54 PM.

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                  #9
                  What usually happens is that a smaller distribution transformer blows up, but the sudden loss of load on the system creates a voltage surge that other transformer tap changers cannot react to fast enough and protective relaying starts cascading to shut down more and more systems in a concentric ring around the initial failure. But they can't re-energize all at once until they know where the initial fault took place.

                  PS: This is not to say there wasn't some sort of secondary problem with their relaying, there likely was/is because it's not SUPPOSED to happen this way. So the investigation will hopefully get to the bottom of that issue.
                  Last edited by Jraef; 07-15-19, 08:00 PM.
                  __________________________________________________ ____________________________
                  Many people are shocked when they discover I am not a good electrician...

                  I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

                  Comment


                    #10
                    Originally posted by gar View Post
                    190714-1945 EDT

                    The reporting on this problem is interesting.

                    It has been said that about 70,000 customers lost power. I am not in the power industry and have little knowledge about it. But searching for a few tidbits and knowing what my power consumption is I can make some assumptions.


                    .
                    70,000 customers sounds, on the one hand, like a lot of customers, but on the other hand, how many customers are there in NYC?

                    Comment


                      #11
                      Originally posted by ggunn View Post
                      70,000 customers sounds, on the one hand, like a lot of customers, but on the other hand, how many customers are there in NYC?
                      Exactly. Presuming that mostly means how many metered services are out. How many small apartments are there with fairly limited load in NYC and one meter on the system? How many small businesses with somewhat limited load?

                      1 large high rise building might have a good chunk of that 70,000 people in it during normal "business hours" but may or may not be counted same way as other things I mentioned above.
                      I live for today, I'm just a day behind.

                      Comment


                        #12
                        190715-2016 EDT

                        ggunn:

                        I was using the 70,000 customers to try get an estimate of the size of a single transformer to support that load. But I also don't think a single transformer was the cause. That is why I mentioned a cascading event.

                        I have now done a search for the weight of a 100 MVA transformer. Found this site https://www.btbplaza.com/index.php/e...a-220-33-kv-09
                        It lists a weight of 104,900 kg or at 2.2 #/kg the weight is 230,780 # or 115 tons. Huge to quickly change.

                        It is possible this is the size of the transformer going to our local substation.

                        .

                        .

                        Comment


                          #13
                          Originally posted by gar View Post
                          190715-2016 EDT

                          ggunn:

                          I was using the 70,000 customers to try get an estimate of the size of a single transformer to support that load. But I also don't think a single transformer was the cause. That is why I mentioned a cascading event.

                          I have now done a search for the weight of a 100 MVA transformer. Found this site https://www.btbplaza.com/index.php/e...a-220-33-kv-09
                          It lists a weight of 104,900 kg or at 2.2 #/kg the weight is 230,780 # or 115 tons. Huge to quickly change.

                          It is possible this is the size of the transformer going to our local substation.


                          .

                          .
                          Another problem is how things tie together and what may be automatically transferred when something fails. The further upstream you go into distribution the more customers will normally be impacted (some large industrial customers can skew this at times). Initial failure that triggered things could have been at lower level, if some of the lost loads begin to transfer to working sources a cascading event like you mentioned could result in even more demands on still working sources and at some point they must open some or even all their output to prevent overloading.
                          I live for today, I'm just a day behind.

                          Comment


                            #14
                            The most recent and most plausible description, from earlier today, from ConEd, was that a 13kV cable failed and the protective relaying system intended to isolate such a fault did not function as designed/intended, allowing the short circuit to bring down interconnected distribution equipment throughout a good part of the city. If the fault was a simple short, both ends of the cable would have to be opened to allow the rest of the system to continue normal operation. A failure of the relaying at either end could cause problems, especially if cable was used bidirectionally or in parallel with another route.
                            So it was not a question of discovering and fixing a fault in a limited portion of the system but rather manually isolating the system and repairing collateral damage, even when the fault location was determined.

                            We will see what else comes out in coming days.

                            Comment


                              #15
                              I live and work in NYC keep in mind that when they say " customer" that means a single account/meter alot of buildings in the city only have one meter , so one building could have 3-400 units in it but still be considered one customer According to edison

                              Sent from my SM-G965U using Tapatalk

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