This is great! My company has a very similar substation on a solar farm we maintain. It's all new to me and I'm picking up all kinds of nuggets of info from this video
Brilliant video, cheers. As an electrician of 30 years I have seen and worked on most things but never the HV grid side. This stuff fascinates me, especially the fault protection and currents involved. Thanks.
Very nice overview of the various systems. I would also have liked to see more of the protective relays. I'm involved with testing medium voltage (5 kV - 25 kV) breakers, CT's/PT's, relays, and NGR's. So I enjoyed this video a lot; thanks for sharing.
Pretty awesome tour, certainly a lot more LV/signal/control wiring then I would of imagined! I had wanted to be a substation builder/engineer, but such is life when you have many interests, you have to settle on one. Would be so enjoyable to build these, especially the control panels
16:50 I suspect that the mA meter measures the current going through at all times. While the counter just cares about the big surges. Lightning strikes are usually not measured in mA, but rather kA-MA. I suspect the surge protectors are made with metal oxide veristors, these get progressively more leaky with each discharge through them. At some point they start to run quite warm and risk failure from that alone. Periodically checking the leakage current will allow one to change it out before it fails. Another style of these surge protectors use explosives to signal a failure. Ie literally blowing up when they get too worn out. Downside here is that one then don't have a surge protector... 24:40 A rough rule of thumb is about 3 kV/mm, or 76 kV/inch. So 2-3 inches of air gap should be plenty to not fry birds at these relatively low voltages. Even if the breakdown voltage does get lower around sharp edges, but that usually don't make a massive difference.
@@imeprezime1285 Yes, explosively charged fuses and surge protectors are great for preventing arcs and "safely" remove themselves from the system. Downside is that they are as stated, explosive. They work by fairly trivial means, usually some thermal trigger. Ie a compound that ignites above some temperature. That in turn detonates the main charge. But not all high voltage fuses and surge protectors use this approach.
Thanks for the tour! I particularly enjoyed your insights into the data links and remote control capabilities. My day job involves assessing the security of SCADA/ICS and remote control systems in industrial environments (private, public utility, and marine) so it was very interesting to see how the power utilities do things in the US compared to what I've seen elsewhere.
You guys have lifetimes of knowledge that I know very little about. After reading your comment I looked into how many points we gather for SCADA from the substation. 548 points. 286 are analog, the rest digital. I am not sure how many of those the Utility grabs. Lots of info!
@@spdfreakls1 That's quite a bit of telemetry! Sounds like a modern system. The trend seems to be going towards long-term collection of as much data is available, for trend analysis and failure prediction. Luckily at the 100kV+ substation level there's enough aggregation going on to avoid any individual privacy issues with the data, which tends to be a problem for smaller utility sites (e.g. being able to tell when someone has a shower by looking at the water mass flow rate... creepy!)
Speaking as a retired electrical engineer in the electric power industry, the discharge devices connected in the path of the lightning arresters are present for condition monitoring. The lightning arresters are composed of a series string of metal-oxide varistor blocks (looks like a hockey puck). The string of blocks can handle a certain amount of energy flow from the lightning stroke. For example, a stroke might have 15,000 amps of current/energy and that amount will flow through the string of arrester blocks. When a lightning strike occurs, the stroke will increment the counter by 1 and it will display the amount of energy in the stroke. A substation technician can make an inspection after an event like a breaker trip or a lightning storm and see if the discharge meters have recorded a reduction in remaining life in the arresters.
At 13:06 I noticed the fan blades are different than a normal cooling fan...I'm curious of why the fan blades looks like they kinda overlap closer together than normal blades which they are spaced apart from each other...is it because for cooling efficiency purposes?
Wow the controls in each of those boxes/equipment chassis is way more involved than I would have imagined. But it makes sense, everything will have alarm points and controls for SCADA and there is presumably a NOC somewhere that would be watching all of this.
Nice walk through and good catch on the transformer neutral bus that renders the reactor useless! First time I have seen that style Qualitrol gauge before and did the guys who put the temp sensor junction box covers and capillary tube guard on upside down on purpose, so the 73 is upside down to piss someone off? As far as the strike counters on the LA's. We had an LA (115V) blow about a year ago and it totally blew the strike counter to pieces! Only had them on one transformer and we never trended the leakage, maybe if we did we could have predicted a pending LA about to fail, or there was some transient that took it out anyway. Was never investigated, just took over a year to get a new set of LAs.
@@spdfreakls1 Yeah, no idea what the issue was. Just run of the mill 115kV substation class LAs. The originals were Ohio Brass, not sure if they were trying to go back with the exact same brand / model or what. I just find and fix, glad I don't do the parts searching end if it.
I'm a bit puzzled by the station aux xfmr connection. Is it connected L-N or L-Gnd? What happens to the station service voltage when there is a L-Gnd fault on the 34.5kV? Also, is there a second station service source.
@@fredlotte2601 primary is line to ground. Secondary has a grounded neutral. Sometimes the neutral is grounded at the transformer case or inside the 400a disconnect below. If there is a L-gnd fault on 35kv side on the same phase at the transformer is connected to it will affect secondary voltage. Yes, there is a secondary utility backup. There is an automatic transfer switch in the control building.
@@fredlotte2601 In my experience I have seen single phase L-N and L-L station service transformers and some larger stations, three phase transformers. Usually with a second station service transformer fed from a second distribution transformer, if there is one. And yeah, when there is a fault you can lose station service but most of the critical substation devices run on DC, from the battery charger when AC is available and from battery when AC goes out. I've been in stations with DC lighting too and of course some also have back up generators. But all the critical devices, like protective relays and your trip coils, close coils, depending on the station, spring charge motors, motor operated disconnects will all be DC. More so in transmission yards, not sure about wind farm subs, never have been in one (yet).
I think you should do some tests on the transformer cooling fans, since in the narration there was a statement about the critical need for effective forced convection cooling to prevent the transformer from overheating. The fan cooling design seems wrong to me. For example, lets say the transformer external oil heat sink allow natural convection from the bottom of the radiator to the top. In other words, think of a box housing the radiators with an opening on the top and on the bottom, but with the sides enclosed, like a rectangular tube. Cooler air would enter the bottom flow upward as it absorbs heat from the radiator fins and exit at the top, natural convection produces an upward flow of air as it is heated. The cooling fins internal to the box would have to be spaced appropriately to allow air flow around the radiator tubes. Then if we wanted to add two stages of forced convection (cooling fans) ONAF1 and ONAF2, as staged additional cooling you would put the fans pulling (air flow up) on the top and pushing on the bottom (air flow up). When both banks of fans are on they work together to move air through the radiator from the bottom to the top. The first stage ONAF1 should be the top mounted fans and ONAF2 the bottom mounted fans. To make the flow rate consistent across the radiator you would want all the fans, either top or bottom, to come on together (and off together), meaning all the top fans (or bottom fans) all off or all on. To make the top and bottom fans work effectively you would want a mounting plate or formed end cap across the entire top and the bottom with round cutouts the same diameter of the fans. This way the fans are able to product a static pressure as seen by the cooling box. If you place a fan on a radiator without producing a static pressure the air flow will just exit without being forced through the fins. Meaning the cooling effect is very small. You can also think of it this way, lets say instead of the many smaller fans we just had one large round fan with a diameter the same size as the width or the side of the radiator, so it covered the radiator but without a blocking plate or flow plate. The fan would be a puller so air would enter the middle of the radiator and be forced outward from the side, but you would have a huge amount of leakage around the periphery of the fan. Using the same single fan we now add a blocking plate, but instead of a flat plate we make an end cap with a standoff distance of about a foot from where the radiator plates stop with a sealed periphery along the outline of the radiator. With this formed sealed end cap air can be drawn through out the entire radiator with the large single fan because the static pressure is spread over the entire face of the radiator. You could do the same with several smaller fans but you would have the same end cap but with several smaller round cutouts for all the individual fans, with the requirement that all the individual fans would have to be on together, working as a bank of fans. The best way to see the effects of your cooling approach is to use a thermal camera to see hot spots and how the heat energy is being conveyed to ambient.
The cooling setup is not something the installing company made up themselves. It is designed and tested in the factory and they have verified the transformer can run continuously at the rated load with the fans provided in the factory made mounting spots.
True! It varies by state. In Texas, they are specific to exclude private and public utilities, however our contract and design guidelines reference being NEC complainant. This means its a contractual requirement to be compliant , not a state requirement.
Is there any sort of regulation sub stations or utility and power companies have to work within for electro magnetic interference "noise"? I can't imagine there's any way to be 'minimal', but I wondered if there was a regulated limit or something? Great video!!
The only "noise" electrically I can think of is VAR's (dirty power) and that's regulated by equipment in the substation. Yes, the utility puts fairly strick limits in place for true power (.95 lag-.95 lead) with "1" being true power.
It looks like the 34.5k VAC three phase feed is center tapped Y (overhead three large line conductors and one small neutral conductor). Which would make the line to neutral voltage 19.9k VAC (Y phase voltage) which feeds the 100kVA transformer producing center tapped 240 VAC (two legs of 120 VAC) single phase. In my experience you should not use the word ground to describe the connection to the three phase Y center tap. It is call a neutral connection. If this connection is also earthed for lightning safety then it should be call earthing and not grounding. Grounding is a method of bonding and not connected to the dirt below your feet (even though we walk on the ground), connection to the dirt using grounding rods is called earthing (even though we call the rods grounding rods, they really should be called earthing rods) to specifically distinguish it from grounding which is really a part of bonding. In fact we would not really need to earth the system, which would reduce the risk of electric shock, if it where not for accommodating lightning. So the 100kVA transformer is powered by a phase to neural, this neutral is also earthed for lighting protection, but the ground "the earth", does not normally carry any current except for lightning. The transformer is not grounded it is earthed. It should be noted that the reason we have the rocks in the yard is to elevate the workers from a wet earth, which can create a dangerous voltage gradient along the ground (damp earth) if a lighting strike should occur. Grounding, meaning a current path, is really a misnomer term in reference to the USA National Electric Code. Where even though you will see the word ground used, as in ground wire, it is generally considered bonding in that there is a path for ground fault currents to trip a breaker. Meaning if I have a ground wire as part of a 20 Amp 120 VAC branch circuit the ground wire is really a way to bond (connect) the receptacle ground wire to the breaker panel to provide a path for ground fault current to trip the circuit and protect the dwelling occupants. But, to operate correctly this connection is not connected to the dirt we walk on, current does not flow through the earth for ground fault, it flows through a wire back the main panel. At the main service this connection is earthed using grounding rods. Earthing is there to provide a path for lightning current as to not enter the dwelling. Grounding is in reference to bonding to enable tripping a breaker during a ground fault. Ground fault current does not flow through the earth (ground). Yes it is very confusing, but we need to understand the differences in AC distribution between grounding, bonding and earthing.
Is it commmon that the MV switchyard is outdoor and air insulated? Here in germany the MV side is always build as an compact gas-insulted switchgear inside the substation building.
it is common, mainly because it is cheapest. There are metal clad switch gear buildings that can achieve the same thing with a much smaller footprint. This would make sense in a city environment or location where land is expensive.
It's the same thing in Sweden. Even in the middle of nowhere all medium voltage switches are in cabinets inside the station building. It's always built so you can replace a switch or PT/CT without disconnecting the transformer.
5:02 Good thing you opened that switch control box before turning it on..that "open" plate was touching (or very close to) that terminal on the block, would have made for a bad day. You may also need to pound into everyone's heads that a control cabinet is NOT a storage box for parts, especially metallic ones.
When cabinets are built in a factory all associated parts are commonly placed inside, then after they are mounted on site the installers will take out the parts and mount them or place in the station storage. Shipping parts in separate packages VERY often leads to them getting lost, and a lot of them cannot be ordered as spares you have to reorder entire components just because a small mounting bracket got lost.
Sometimes at my old company we used the tertiary winding as a HV source for our substation lv auxiliaries on multiple transformer stations. They are delta connected to absorb third harmonics generated in star connected higher voltage windings. This causes a issue with no natural star point on the source windings so the primary on our 3 phase Aux transformers where star connected to produce a return path for HV faults and third harmonic currents at that voltage level.
@@noelcastle3986 yeah I also know tertiary winding for auxiliary transformer or reactive power compensation but in the video the auxiliary transformer was at one of the phases of the 33 kV bay
Yow, that battery bank with high voltage DC at infinite amps exposed on the top scares me more than anything else in that yard! And I would consider cutting the part about the stupid rule, it might ruffle the wrong feathers... Lol
@@spdfreakls1I appreciated your comments and was laughing at the incongruity of the rules compared to the terminal velocities, but I was also hearing all the YT keyword alerts going off, and imagining the Utility Karens hitting Report for Inciting Transformers. I have also been careful in my comments to avoid scary words lol Thank you for the videos, I find them fascinating, and possibly inspiring me to change careers!
Can you please tell me how to calculate, the fuses in the primary for a transformer 600 volts, 3 phases, 75 KVA? Primary Delta and secondary Why. Thanks.
It's basically a mark made with a paint pen across both the nut and bolt, indicating that it was properly torqued, but if the nut backs off you will see the paint is broken and the mark on the nut no longer lines up with the mark on the bolt. So it's a quick visual indicator of proper torque, and if the nut has moved at all.
I may be able to. While the devices themselves are not anything private, certain owners get a little nervous about showing them. I'll see what I can do.
They do this in long term (hours) but when there is a sudden load change (seconds) a signal has to be sent to immediately reduce production in order to prevent the frequency rising too much.
You can't count? There are 5 rows, 6 columns, 2 frames - so 60 batteries, and they are most likely "2V" per cell. (standard lead-acid. 2.3-2.4 max.) (Hint: they're also numbered with their position in the string.)
I can count, but not very high. i didn't want to waste peoples time by watching me count. First time in that building. I explained the theory about how we got to 120 VDC and moved on.
When you connect disconnect from the utility isn't there a large bouncing resonating amount of energy that has to be absorbed basically dump to ground?1
This is great! My company has a very similar substation on a solar farm we maintain. It's all new to me and I'm picking up all kinds of nuggets of info from this video
Love the substation vids! Hopefully this one doesn't get taken down.
Us too!
Why do they get taken down
Yes, why?
Brilliant video, cheers. As an electrician of 30 years I have seen and worked on most things but never the HV grid side. This stuff fascinates me, especially the fault protection and currents involved. Thanks.
Very nice overview of the various systems. I would also have liked to see more of the protective relays. I'm involved with testing medium voltage (5 kV - 25 kV) breakers, CT's/PT's, relays, and NGR's. So I enjoyed this video a lot; thanks for sharing.
Nice video. 45 year 600volt retired Master from Maryland. We don't have any windfarms substations in our area.
Pretty awesome tour, certainly a lot more LV/signal/control wiring then I would of imagined! I had wanted to be a substation builder/engineer, but such is life when you have many interests, you have to settle on one. Would be so enjoyable to build these, especially the control panels
16:50 I suspect that the mA meter measures the current going through at all times.
While the counter just cares about the big surges. Lightning strikes are usually not measured in mA, but rather kA-MA.
I suspect the surge protectors are made with metal oxide veristors, these get progressively more leaky with each discharge through them. At some point they start to run quite warm and risk failure from that alone. Periodically checking the leakage current will allow one to change it out before it fails.
Another style of these surge protectors use explosives to signal a failure. Ie literally blowing up when they get too worn out. Downside here is that one then don't have a surge protector...
24:40 A rough rule of thumb is about 3 kV/mm, or 76 kV/inch. So 2-3 inches of air gap should be plenty to not fry birds at these relatively low voltages.
Even if the breakdown voltage does get lower around sharp edges, but that usually don't make a massive difference.
Use explosives?
@@imeprezime1285 Yes, explosively charged fuses and surge protectors are great for preventing arcs and "safely" remove themselves from the system.
Downside is that they are as stated, explosive.
They work by fairly trivial means, usually some thermal trigger. Ie a compound that ignites above some temperature. That in turn detonates the main charge.
But not all high voltage fuses and surge protectors use this approach.
@@todayonthebench Gee...I wouldn't like be in vicinity when they fail 🤪
Thanks for the tour! I particularly enjoyed your insights into the data links and remote control capabilities. My day job involves assessing the security of SCADA/ICS and remote control systems in industrial environments (private, public utility, and marine) so it was very interesting to see how the power utilities do things in the US compared to what I've seen elsewhere.
You guys have lifetimes of knowledge that I know very little about. After reading your comment I looked into how many points we gather for SCADA from the substation. 548 points. 286 are analog, the rest digital. I am not sure how many of those the Utility grabs. Lots of info!
@@spdfreakls1 That's quite a bit of telemetry! Sounds like a modern system. The trend seems to be going towards long-term collection of as much data is available, for trend analysis and failure prediction. Luckily at the 100kV+ substation level there's enough aggregation going on to avoid any individual privacy issues with the data, which tends to be a problem for smaller utility sites (e.g. being able to tell when someone has a shower by looking at the water mass flow rate... creepy!)
Love the electrical videos! Glad to hopefully see them coming back!
I worked a facility with 230Kv and 100 subs and loved it!
Thanks for the tour.
Thank you, really interesting tour.
Man these videos are interesting. Thanks for sharing!
Great video! Love these walkthroughs and explanations!
@15:26 where do u measure the gas amount, that the transformer produces? in germany it is called "Buchholz Relais"...
Yes! We have those as well, they are on the top of the transformers. I have a video to release soon that shows those!
Speaking as a retired electrical engineer in the electric power industry, the discharge devices connected in the path of the lightning arresters are present for condition monitoring. The lightning arresters are composed of a series string of metal-oxide varistor blocks (looks like a hockey puck). The string of blocks can handle a certain amount of energy flow from the lightning stroke. For example, a stroke might have 15,000 amps of current/energy and that amount will flow through the string of arrester blocks. When a lightning strike occurs, the stroke will increment the counter by 1 and it will display the amount of energy in the stroke. A substation technician can make an inspection after an event like a breaker trip or a lightning storm and see if the discharge meters have recorded a reduction in remaining life in the arresters.
The MOVs must get really hot after a lightning strike. It is just incredible that they can shunt that amount of energy and survive.
At 13:06 I noticed the fan blades are different than a normal cooling fan...I'm curious of why the fan blades looks like they kinda overlap closer together than normal blades which they are spaced apart from each other...is it because for cooling efficiency purposes?
Thanks very much for the video.
great video.
Wow the controls in each of those boxes/equipment chassis is way more involved than I would have imagined. But it makes sense, everything will have alarm points and controls for SCADA and there is presumably a NOC somewhere that would be watching all of this.
Nice walk through and good catch on the transformer neutral bus that renders the reactor useless! First time I have seen that style Qualitrol gauge before and did the guys who put the temp sensor junction box covers and capillary tube guard on upside down on purpose, so the 73 is upside down to piss someone off?
As far as the strike counters on the LA's. We had an LA (115V) blow about a year ago and it totally blew the strike counter to pieces! Only had them on one transformer and we never trended the leakage, maybe if we did we could have predicted a pending LA about to fail, or there was some transient that took it out anyway. Was never investigated, just took over a year to get a new set of LAs.
Wow that is crazy! Yeah these lead times are insane. We can get a main power transformer faster than an HV breaker these days.
@@spdfreakls1 Yeah, no idea what the issue was. Just run of the mill 115kV substation class LAs. The originals were Ohio Brass, not sure if they were trying to go back with the exact same brand / model or what. I just find and fix, glad I don't do the parts searching end if it.
I'm a bit puzzled by the station aux xfmr connection. Is it connected L-N or L-Gnd? What happens to the station service voltage when there is a L-Gnd fault on the 34.5kV? Also, is there a second station service source.
@@fredlotte2601 primary is line to ground. Secondary has a grounded neutral. Sometimes the neutral is grounded at the transformer case or inside the 400a disconnect below. If there is a L-gnd fault on 35kv side on the same phase at the transformer is connected to it will affect secondary voltage. Yes, there is a secondary utility backup. There is an automatic transfer switch in the control building.
@@fredlotte2601 In my experience I have seen single phase L-N and L-L station service transformers and some larger stations, three phase transformers. Usually with a second station service transformer fed from a second distribution transformer, if there is one. And yeah, when there is a fault you can lose station service but most of the critical substation devices run on DC, from the battery charger when AC is available and from battery when AC goes out. I've been in stations with DC lighting too and of course some also have back up generators. But all the critical devices, like protective relays and your trip coils, close coils, depending on the station, spring charge motors, motor operated disconnects will all be DC. More so in transmission yards, not sure about wind farm subs, never have been in one (yet).
13:15 The way the fans wire is run.
Yeah, not very pretty!
Love these videos...keep em coming 😁
I think you should do some tests on the transformer cooling fans, since in the narration there was a statement about the critical need for effective forced convection cooling to prevent the transformer from overheating. The fan cooling design seems wrong to me. For example, lets say the transformer external oil heat sink allow natural convection from the bottom of the radiator to the top. In other words, think of a box housing the radiators with an opening on the top and on the bottom, but with the sides enclosed, like a rectangular tube. Cooler air would enter the bottom flow upward as it absorbs heat from the radiator fins and exit at the top, natural convection produces an upward flow of air as it is heated.
The cooling fins internal to the box would have to be spaced appropriately to allow air flow around the radiator tubes. Then if we wanted to add two stages of forced convection (cooling fans) ONAF1 and ONAF2, as staged additional cooling you would put the fans pulling (air flow up) on the top and pushing on the bottom (air flow up). When both banks of fans are on they work together to move air through the radiator from the bottom to the top. The first stage ONAF1 should be the top mounted fans and ONAF2 the bottom mounted fans. To make the flow rate consistent across the radiator you would want all the fans, either top or bottom, to come on together (and off together), meaning all the top fans (or bottom fans) all off or all on. To make the top and bottom fans work effectively you would want a mounting plate or formed end cap across the entire top and the bottom with round cutouts the same diameter of the fans. This way the fans are able to product a static pressure as seen by the cooling box.
If you place a fan on a radiator without producing a static pressure the air flow will just exit without being forced through the fins. Meaning the cooling effect is very small. You can also think of it this way, lets say instead of the many smaller fans we just had one large round fan with a diameter the same size as the width or the side of the radiator, so it covered the radiator but without a blocking plate or flow plate. The fan would be a puller so air would enter the middle of the radiator and be forced outward from the side, but you would have a huge amount of leakage around the periphery of the fan. Using the same single fan we now add a blocking plate, but instead of a flat plate we make an end cap with a standoff distance of about a foot from where the radiator plates stop with a sealed periphery along the outline of the radiator. With this formed sealed end cap air can be drawn through out the entire radiator with the large single fan because the static pressure is spread over the entire face of the radiator. You could do the same with several smaller fans but you would have the same end cap but with several smaller round cutouts for all the individual fans, with the requirement that all the individual fans would have to be on together, working as a bank of fans.
The best way to see the effects of your cooling approach is to use a thermal camera to see hot spots and how the heat energy is being conveyed to ambient.
The cooling setup is not something the installing company made up themselves. It is designed and tested in the factory and they have verified the transformer can run continuously at the rated load with the fans provided in the factory made mounting spots.
Thanks for the interesting video! What is the lowest power transformer Yn/Yn equipped with a tertiary winding? In Russia, from 40 MBAs
Regarding the NEC strapping requirements on the flexible conduit, NEC "legally" does not apply to utility owned or controlled equipment
True! It varies by state. In Texas, they are specific to exclude private and public utilities, however our contract and design guidelines reference being NEC complainant. This means its a contractual requirement to be compliant , not a state requirement.
Thanks for the walkthrough! A question, if I may:
Do you interlock the HV CB and D/S mechanically?
Via A and B contacts in the wiring.
Is there any sort of regulation sub stations or utility and power companies have to work within for electro magnetic interference "noise"? I can't imagine there's any way to be 'minimal', but I wondered if there was a regulated limit or something? Great video!!
The only "noise" electrically I can think of is VAR's (dirty power) and that's regulated by equipment in the substation. Yes, the utility puts fairly strick limits in place for true power (.95 lag-.95 lead) with "1" being true power.
As a EE, love to see the power side.
It looks like the 34.5k VAC three phase feed is center tapped Y (overhead three large line conductors and one small neutral conductor). Which would make the line to neutral voltage 19.9k VAC (Y phase voltage) which feeds the 100kVA transformer producing center tapped 240 VAC (two legs of 120 VAC) single phase. In my experience you should not use the word ground to describe the connection to the three phase Y center tap. It is call a neutral connection. If this connection is also earthed for lightning safety then it should be call earthing and not grounding.
Grounding is a method of bonding and not connected to the dirt below your feet (even though we walk on the ground), connection to the dirt using grounding rods is called earthing (even though we call the rods grounding rods, they really should be called earthing rods) to specifically distinguish it from grounding which is really a part of bonding. In fact we would not really need to earth the system, which would reduce the risk of electric shock, if it where not for accommodating lightning.
So the 100kVA transformer is powered by a phase to neural, this neutral is also earthed for lighting protection, but the ground "the earth", does not normally carry any current except for lightning. The transformer is not grounded it is earthed. It should be noted that the reason we have the rocks in the yard is to elevate the workers from a wet earth, which can create a dangerous voltage gradient along the ground (damp earth) if a lighting strike should occur.
Grounding, meaning a current path, is really a misnomer term in reference to the USA National Electric Code. Where even though you will see the word ground used, as in ground wire, it is generally considered bonding in that there is a path for ground fault currents to trip a breaker. Meaning if I have a ground wire as part of a 20 Amp 120 VAC branch circuit the ground wire is really a way to bond (connect) the receptacle ground wire to the breaker panel to provide a path for ground fault current to trip the circuit and protect the dwelling occupants. But, to operate correctly this connection is not connected to the dirt we walk on, current does not flow through the earth for ground fault, it flows through a wire back the main panel. At the main service this connection is earthed using grounding rods. Earthing is there to provide a path for lightning current as to not enter the dwelling. Grounding is in reference to bonding to enable tripping a breaker during a ground fault. Ground fault current does not flow through the earth (ground).
Yes it is very confusing, but we need to understand the differences in AC distribution between grounding, bonding and earthing.
Good catch on the transformer neutral bus that renders the reactor useless.
I love you, dad
If eye wash station is for battery acid it should be working before the batteries are brought in / charging. Put a live sign on it, people will learn.
Is it commmon that the MV switchyard is outdoor and air insulated? Here in germany the MV side is always build as an compact gas-insulted switchgear inside the substation building.
it is common, mainly because it is cheapest. There are metal clad switch gear buildings that can achieve the same thing with a much smaller footprint. This would make sense in a city environment or location where land is expensive.
ok interesting, because here in germany, even in the middle of nowhere, nobody is doing MV outdoor air insulated @@spdfreakls1
@@arne0498 That is very interesting! Learn something new every day, especially from the comments!
It's the same thing in Sweden. Even in the middle of nowhere all medium voltage switches are in cabinets inside the station building. It's always built so you can replace a switch or PT/CT without disconnecting the transformer.
you guys do quite a few things differently )) for one - there's no gravel in the subs, it's all grass!
Nice vid! I've been wondering what those components were right after the high side disconnect.
5:02 Good thing you opened that switch control box before turning it on..that "open" plate was touching (or very close to) that terminal on the block, would have made for a bad day. You may also need to pound into everyone's heads that a control cabinet is NOT a storage box for parts, especially metallic ones.
When cabinets are built in a factory all associated parts are commonly placed inside, then after they are mounted on site the installers will take out the parts and mount them or place in the station storage.
Shipping parts in separate packages VERY often leads to them getting lost, and a lot of them cannot be ordered as spares you have to reorder entire components just because a small mounting bracket got lost.
Very interesting video
What purpose does the 13,8 kV level of the transformer have?
Great question! that is the tertiary winding. it helps with harmonics and stabilizes the neutral. Ill try to cover that more in the next video!
are there any external devices connected to this winding or is it an internal winding?@@spdfreakls1
Sometimes at my old company we used the tertiary winding as a HV source for our substation lv auxiliaries on multiple transformer stations. They are delta connected to absorb third harmonics generated in star connected higher voltage windings. This causes a issue with no natural star point on the source windings so the primary on our 3 phase Aux transformers where star connected to produce a return path for HV faults and third harmonic currents at that voltage level.
@@noelcastle3986 yeah I also know tertiary winding for auxiliary transformer or reactive power compensation but in the video the auxiliary transformer was at one of the phases of the 33 kV bay
@@spdfreakls1 is the capacitor bank connected to the tertiary winding maybe?
I hear solar farms are more difficult due to the rapid swings in power due to clouds.
So are there people always in that little substation shack? I always see them, but never see anyone working.
They are typically not manned. Everything can be seen and controlled remotely.
@@spdfreakls1 Cool. I always wondered what went on in those things.
Yow, that battery bank with high voltage DC at infinite amps exposed on the top scares me more than anything else in that yard!
And I would consider cutting the part about the stupid rule, it might ruffle the wrong feathers... Lol
YT is cutting it now thanks. Sometimes i forget bad actors are also watching.
@@spdfreakls1I appreciated your comments and was laughing at the incongruity of the rules compared to the terminal velocities, but I was also hearing all the YT keyword alerts going off, and imagining the Utility Karens hitting Report for Inciting Transformers.
I have also been careful in my comments to avoid scary words lol
Thank you for the videos, I find them fascinating, and possibly inspiring me to change careers!
Can you please tell me how to calculate, the fuses in the primary for a transformer 600 volts, 3 phases, 75 KVA? Primary Delta and secondary Why.
Thanks.
19:17 "Resistance is Futile"
👍✌
What are torque marks? Why do you need them?
They're an indicator that who ever torqued them has done so. (when you torque it down, you put that mark on there.)
It's basically a mark made with a paint pen across both the nut and bolt, indicating that it was properly torqued, but if the nut backs off you will see the paint is broken and the mark on the nut no longer lines up with the mark on the bolt.
So it's a quick visual indicator of proper torque, and if the nut has moved at all.
@@ke6gwf and @jfbeam Thanks for the explanation!
This is probably a dumb question are you able to talk about and show the protection control relays?
I may be able to. While the devices themselves are not anything private, certain owners get a little nervous about showing them. I'll see what I can do.
Are you a superintendent or engineer?
Neither sir! Just helping out where I can and learning every day!
Fortune Electric transformer. Offshore built
fine thank
The utility should instead adjust prices. Negative if energy is not required, and higher the more power is required.
They do this in long term (hours) but when there is a sudden load change (seconds) a signal has to be sent to immediately reduce production in order to prevent the frequency rising too much.
weak point seems to be the cooling fins and the gas cylinder
Scared place on earth. Never to come ever close to a substation. Rather be in a war zone or a haunted cemetery.
You can't count? There are 5 rows, 6 columns, 2 frames - so 60 batteries, and they are most likely "2V" per cell. (standard lead-acid. 2.3-2.4 max.)
(Hint: they're also numbered with their position in the string.)
I can count, but not very high. i didn't want to waste peoples time by watching me count. First time in that building. I explained the theory about how we got to 120 VDC and moved on.
138 kV, that's cute. Come back with a 500 kV one and then I'll watch it.
You're mumbling.
Ill sign up for speech lessons in my spare time. Sorry.
When you connect disconnect from the utility isn't there a large bouncing resonating amount of energy that has to be absorbed basically dump to ground?1