Basic components of a power grid

what's up guys you're watching Bob's decline lemon blogger we've got a gorgeous day outside today the birds are chirpin the Transformers humming we're gonna be doing things a little bit different here today I get quite a few questions on my youtube channel on Facebook Instagram I try my best to answer everybody's question to the best of my knowledge so today I got an instant message from Jason and his question was how does the system know there is an issue and no one to open the cut-out fuse and what causes a transformer to blow instead of the cut-out fuse so Jason what I'm going to do to answer your question I'm actually going to make a video and we're gonna cover the system from the power transformer right through to the house that way I can better explain how the system isolates a fault why I cut out blows why transformer might blow instead of a cut out all right so that questions from Jason guys and his YouTube channel is Liftmaster 1280 looks like he might specialize in garage doors just quite a few videos on his channel all to do with garage doors so that's Jason guys from Liftmaster 1280 check it out thanks for the question so big shout out to that let's get started though this is our power transformer it's just a tiny little guy beat in the rural area most of them are much bigger than this we have 69 thousand volts coming in here in 12,000 470 coming out going through here we have our first protection device we call it an impeller up tur so the Intel Eruptor basically has a setting it's got some relays in it if the current exceeds the setting it will trip the shut off power you might have a small branch fall down on the system and the arc flash clears the branch falls to the ground there's no longer a Fault in the lines this and taller Reptar will actually automatically turn the power back on if it's still detects a fault it will do it up to a total of three times depending on the settings for your particular company or your area we can also take what is called a hold off and basically that sets the entire up tur to a one trip setting once that power trip so it will not come back on much the same as if there's a major fault phase line on the ground it's drawn to 3,000 amps that and teller after will not close back in in those circumstances okay so we're gonna take a step back to our power transformer again for a second there's a fault in the power transformer itself but we have in that case are these high tension fuses you can see there's a set of switches up top and below that set of switches are those orange fuse barrels so if there is a fault in this power transformer those puppies are going to blow they're violent they're loud it's not something that happens very often the first piece of equipment on our line after the oil reclosure or the entire is a set of voltage regulators sometimes these things are built directly into the power transformer itself so what these units do is they monitor the voltage through a control panel and again a bunch of relays equipment here there's a control panel for each unit so as load increases at say dinner time when everyone turns their oven on puts a huge draw in the line that draw brings the voltage down that voltage regulator will then tap up we call it there's actually a mechanical tap that slides along the windings to adjust the ratio which increases the voltage so that the voltage delivered to our customers houses is that a stable level that is set somewhere around 120 volts phase to ground and of course as the load comes off the line that vultures are going to start to skyrocket up very quickly again these units will detect that that mechanical device will slide across the coils it will increase the ratio in order to reduce the voltage this helps keep the voltage supplied to our customers between a set parameter and acceptable voltage can generally fluctuate plus or minus 5% we tend to keep the voltage on the higher scale close to the substation this has got to travel a long way and as it travels through the line there is a voltage drop you will probably see another set of these voltage regulators maybe 10 20 kilometers down the road you get your voltage here as it's traveling the customer that voltage level is going down especially in rural areas we will have some voltage regulators out in line to boost that back up as it decreases break so so far we've got our power transformer we've got our Intel Eruptor which could also be a reclosing device an all-over closure vacuum enclosure a breaker they all cover the same purpose our next piece of equipment is the voltage regulator let's go and take a drive down the line and see what's next alright guys so our next major equipment on the distribution feeder is a set of switches so the doors in these load brake cutouts are actually solid copper doors their specs are that they are rated for 300 amps now that's 300 amps under normal system usage if there's a fault down the line for let's say even 2000 3000 amps chances are it's not gonna affect those doors at all it's gonna bypass right through them back to the Intel erector and trip power back at the substation we can then use these as an isolation point we can open those doors and take work from it from this location back to the fault that way we don't interrupt power to the customers that are on the source side of this pole so we're on the same line here in just a head you will see a three-phase side line again with a set of cutouts now looking in our system these cutouts are fused at 40 amps let's say there's a problem a tree falls across the three phases here it's going to blow these fuses fairly quickly so it's not unusual if there's a Fault in the line that blows the set of cutouts on a sideline for the intolerant or the over closure to trip out that cut it will blow the Intolerable turn power back on up to the cutout that blew and remain in the closed position that way the power is only interrupted to a minimal amount of customers so we're just down the line a little further at our next major piece of equipment and this would be a set of capacitors capacitor bank we call it there's one for each phase now these guys get a little bit more complicated I'm going to try to give you the skinny in about 30 seconds here let's say power runs on the lines at a number 100% now by the time it gets into your home it's at another number ninety seven percent so that three percent is a loss and efficiency of the power that we deliver you are not billed for that three percent you were billed for exactly the power you use at your home but we as a company still have to supply that 100 percent level so that three percent is actually a loss we want the power factor to be as close to 100% as possible you so next in line we've got another set of cutout to see here on all three phases except this time they are fused they're fused with 100 amp fuses so in the end you end up with something like this now keep in mind the amp urges are different depending on the setup you're in the solid doors we've seen earlier were 300 amps we also have 600 amps solid doors there's again many different manufacturers but for today here's what we got we've got our substation going up to a set of 308 solid cutouts then down our next sexualizing point would be 200 amps 140 amps etc etc if there's a fault here let's say a bird gets into the lines across the two phases it wants to blow this set of fuses now that bird is going to cause a fault current of let's say 900 amps so how come that 900 amps it doesn't trip the 140s the 200 back through to the sub and pop that over our fuse can't rip as fast is 1/2 of a cycle now in 1 second there are 60 cycles when everything is working the way it should within that half a cycle that 140 amp fuse will pop a fraction of a second faster than that 200 amp fuses has a chance to pop sometimes the relays are sensitive enough that they will see the current all the way back at the sub that's why we have that Intel Eruptor I called it generally speaking they're more sensitive than the fuses out on the line that is sometimes why you're sitting at home the lights go out boom they come right back on that's from the reclosing device acting at the sub as its supposed to so just because your lights may be flickering a couple times it doesn't mean there's something particularly wrong with your house or your street it could be a fault miles away that's affecting the entire system so how does a fuse know when to blow electricity causes heat that easy electricity can flows through something the less heat there's going to be our fuses are designed to be the weakest point by far within the system so if the wire self is say the size of my finger the fuse is going to be the size of a toothpick it's designed so that if it detects the slightest amount of heat at all it's gonna melt it's spring-loaded it's gonna break apart that wire as quickly as possible this is all stuff that they figured out a long time ago technology hasn't changed much it's a fairly analog setup the bigger the fuse is rated for the bigger the piece of wire inside the more heat it's going to take to melt that fuse link you coordinate these fuse links in the lines so that they get smaller and smaller so it takes less heat ie less current to trip them when everything is coordinated properly you have a system that is more reliable that's able to isolate fault according to where the current spikes are then why is it that sometimes a transformer blows up why doesn't the fuse blow generally speaking when you hear someone say the transformer blew up it didn't it's just the fuse when a fuse blows it's loud it can be pretty aggressive and of course when you see it first then becomes in the line is a transformer just blew up but let's take a look at a transformer because they most certainly do sometimes low up this is just a single phase transformer where you can see the high voltage lead taps on to the main phase so the phases up top are twelve thousand four hundred 70 volts phase to phase that would be approximately 7,200 volts phase to neutral or phase to ground so comes down into our cutout so this particular transformer is a 25 kV a so we have that cutout fused at 6 amps now right in behind the cutout what you see is a lightning arrester the Lightning arrestor is hooked up to the high voltage and has a direct electrical path to ground however there's a series of resistors in there high enough that it won't cause a short for the voltage that's supposed to be in the lines if there's a lightning strike on the lines anywhere at all that's connected to that transformer rather than blowing all of our equipment all the pieces it will drain any excess voltage out through that Lightning arrestor sometimes even blowing lavash to rate apart now if there's a Fault in that transformer what's supposed to happen is the fuse link within that cutout heats up it melts powers out makes a real loud bang some sparks go flying those transformers are actually filled with oil you got your copper windings you got some magnets and you got some oil more load that's on a transformer the more amperage that's flowing through it the more amperage the more heat the oil that's in the transformer helps dissipate this heat from the windings through the oil to the outer side of a transformer if the oil is contaminated it's not going to be insulated well enough to protect that high voltage from shorting out could be water within the oil sometimes little arcs that occur in the transformer especially if it's a voltage regulator that has moving parts inside it the arcing causes carbon windings burn out the same as an element does in your stove it could simply even be just an overloaded transformer that's not drawing quite enough current blow the fuse it's just slowly heating up for days and days maybe even months heating up until that pressure builds up to a point where the pressure release valve can no longer take it and that thing just blows apart a lot of times when a transformer does go bad you'll see black marks all around the pressure release valve as well as an open cut it if that happens most times it's still just going to blow the you try to refuse and close it back in its gonna blow that kind of again the transformer itself probably won't blow up every once in a while when the conditions are just right or wrong I should say sometimes the transformer itself will actually blow up it's very difficult to predict a transformer failing to the point where it actually blows up it doesn't happen very often if ever you arrive to a trouble call and somebody's power flickering you jump out of your truck and you hear sounds like popcorn inside the transformer it's pinging and that means she's ready to blow I want to say open it up as quickly as possible but even that might not be the same thing to do just staring up with that cutout with a stick trying to hook into that ring and ploy it open could be a good way to get hurt if you have another means of killing power to that line sometimes it's the best option you go to the next set of switches back open the line powers out you go back to the transformer that's failing you clear it from the line clear it meaning open the cut out take the top off that transformer is no longer tight wire system energize the main line again and away you go go change that transformer once a transformer is no good we call it a blown transformer but it doesn't mean the transformer actually blew up alright guys so these pieces of equipment that we went over today that are part of a basic power line distribution setup work together to accomplish four different tasks that is one to minimize the outages to our customers when there's a Fault in the line we want it to affect as little people as possible to supply our customers with a steady voltage that doesn't fluctuate too much we don't want that voltage going up too high or too low the equipment that's on the lines is designed to maintain this at all times three it is designed to protect the system any of this equipment that is on the lines is actually designed to protect our system for catastrophic failure when there is a fault and lastly and we just got a trouble call so we're gonna check that out lines are too tight go in the house awesome we're gonna check that out about 30 seconds so lastly we have our system that is to protect the public when something goes bad and wires come down we want that power to trip out as quickly as possible keep everyone safe all right guys thanks again for checking out my channel if you have any questions don't be scared write in the comments below I'll try my best to answer them if it's a question that's outside of my expertise or outside in my experience there's lots guys that watch this channel that are very well educated that I'm sure would be glad to chime in other than that check out my being alignment series where we follow along as I respond to actual trouble calls out on the lines make sure you subscribe and we'll see you next time

Channel: Bobsdecline - Lineman blogger

Views: 51,961

Rating: 4.9717646 out of 5

Keywords: basic equipment on power grid, power line equipment, how do power lines work, how do powerlines work, why did my power go out, why does my power go off and on, why does my power flicker, lineman, power lineman, powerlines, electrical grid, power grid, how does a power grid work, how does power go out, intelliruptor, capicitor bank, power line devices, life on the lines, electrical grid explained, power grid explained, oil recloser, apprentice lineman, apprentice power line

Id: qxMImzWqpPY

Length: 15min 44sec (944 seconds)

Published: Mon Apr 27 2020