How Run of the River Hydroelectric Power Station Works

hi John here today we're going to talk about a run of the river hydroelectric power station and I'm gonna explain to you guys what it is and how it works and some of the main features we can see at the top here we've got a headwater that's the water at a higher elevation and we've got tail water which is the water at the lower elevation now the runner of the River Power Station slightly different to a normal power station because there is no reservoir there's no large body of water stored what we actually have instead of a dam is a weir so the water runs along the river here it comes to a weir and then it runs over the top of the weir and continues on its journey now we use the weir to create a body of water at the top and we can use this body of water to create a reliable water head or a reliable head of pressure down to the turbines the actual name for the body of water behind the weir is called pondage and one of the differences between this and other type of hydroelectric power stations is that the weir allows the water to flow over the top so the water flow can continue whereas a dam stops the water flow completely and builds a reservoir so that's one of the differences between a run of the river power station and another type of hydroelectric power station which will actually use a reservoir so a large body of water the big benefit with the run of the river power station is it's a lot easier to get permission to build a run of the river power station obviously if you're flooding a massive valley and people have to move and there's going to be a lot of loss of life all the wildlife is going to be damaged then people don't want that whereas run the river is relatively easy to construct and you don't have a huge impact upon nature or the people living in the area well you might see sometimes is a fish bypass or a ladder and what this is is a means to let fish swim past or back up river and it will usually be like 80 just to the right in this area here or the left of the power station so the fish will swim back up these steps or ladders and then they get around the dam and can continue further upstream this is pretty good because this also reduces the impact of the power station on the wildlife so let's have a quick look then from up here we can see we've got a bit of a pedestrian walkway here they can come and have a look at the power station or at least the top of it and this whole structure is reinforced concrete the water's going to run up it's gonna reach this dammed area it's going to flow over the top and it's going to continue flowing down the river we can see it's going down that way maybe a few waterfalls and then to the lower river or the river a lower elevation but what we want to do is take the water before it goes down the hill and we'll use the elevation difference or the difference in elevation to generate power so the water is going to flow through this item here which is called a sluice gate the sluice gate allows us to close the inlet to the turbines so it might have an emergency in the turbine area or in the power station so we close this gate and that will slam shut and it will hydraulically isolate the turbine so that we know more water flowing down this or in this area and down through the pipe so we've got a great that stops anything getting sucked into the turbines such as large pieces of wood or plastic bags and stuff like that and if we go in fact what we'll do rather than go in through the gate I'll just spin it around here and we'll go out this way you can see there gather where the tree you can see the pipes coming through there and this is known as a penstock so this is leading down to the turbines in the power station I'll just see if I can turn around okay the pipes come running down and it's going into the power station through here me just see if I can go into the power station now and show you where the pipe enters the power station and before we go inside let's just have a look here you can see another valve here this will be a ball valve and we'll also use that to isolate the turbines in an emergency or just during general operation so that controls a valve quite important and let's go now there we go okay so we're underneath the power station what are we looking at inside this casing here is a Kaplan turbine it's a vertically orientated Kaplan turbine so the water comes in flows in through here and into the casing in the casing itself we just have a look inside there's the vertically or intake a Kaplan turbine they will normally be inside here some sort of wicket gate which will allow you to divert water to the Kaplan turbine a Kaplan turbine is more or less like a ship's propeller and here you can see it's vertically orientated is pointing straight down the blades here are what we call CPP or control pitch propeller they'll adjust and you can adjust these blades to vary the amount of power that you wish to generate so if you want to turn the blades to what we call zero angle zero pitch then the water would just flow by and the Kaplan turbine won't rotate so it won't generate any electricity however if we turn them to maximum pitch or the pitch would generate the most amount of thrust or rotation then we can generate the maximum amount of electricity it's pretty useful because if the valves did fail that we looked at earlier then we could turn the blades to zero pitch and we could stop the turbine rotating the water would continue to flow pass because the valves are broken and we can't close them or the sluice gate is broken etc but at least the turbine is not rotating uncontrollably if actually rotates uncontrollably what it'll actually do is hit a over speed limit and a runaway limit and that then sends a signal to the control unit to shut the turbine down so you want to really control the speed and do properly the type of turbine used here the Kaplan turbine is chosen because it actually works very very well at low heads that means the difference in elevation between the upper reservoir and the lower reservoir is very small and the Kaplan turbine is ideal you may even see a horizontal Kaplan turbine or a bulb turbine maybe Francis turbine but not as likely and what you won't see is a Pelton turbine if you want more information about that just go on my youtube channel and check one of the other videos and you'll see we've explained what each of the turbine types do and why they're selected for each job or each application let's back out of there we'll go up into the power stage in fact let's just have a quick look at the pipe while we're there it's got a bit of a shiny appearance but it really been made out of reinforced concrete and we can see the pipe is just flowing here and going out - let's have a look out into the river so there's the pipe exiting here and there is another sluice gate to isolate the turbines now if we go inside let's have a quick look inside the power station inside the power station here is a generator so the shaft comes out of the turbine connects to a generator and we will generate electricity so when the turbine rotates as the water flows through the turbine there's a common shaft to a generator which is s item here and the generator rotates or more specifically the rotor rotates and we generate electricity and then when we've generated some electricity we obviously need to deliver that to people's houses and there's some cables coming out here and this is going along there and it'll actually go into a room which is called the switch gear room so see there you go it's coming in through this section there and it goes to what we call switch gear switch gear is used to protect the generator it prevents any damage that may occur due to over voltage or over current so if there's any large fluctuations in voltage in the line or current the switch gear will open kind of like a large switch but it's done automatically and this protects your generator remember the generator is quite expensive you don't want huge currents and use your voltages going to the generator you want to protect it and that's exactly what the switch gear here does in addition to that it's also very useful if you'll do maintenance on the generator to isolate it in fact it's not useful issues as a requirement you'll need to isolate the generator completely so safe to work on and you will I salute it here at the switchgear typical voltages here for the switch gear may be ten thousand volts or six thousand volts for example 6 kV 10 kV 20 kV and the type of switch gear used could be air insulated or vacuum insulated or maybe sf6 at some point we'll make a video on switch gear and I'll explain to why we use different types of switchgear and for what purposes let's go through the walks that's whether the cabling seems to be going I'll spin around here and try and get rid of you okay so there's a cabling coming out of here and it connects to this green item which is a transformer now the green transformer is actually all insulated or fluid insulated and it's going to increase the voltage we're going to increase it to for example 110,000 volts you need to increase the voltage because if you don't increase the voltage you're going to need huge cables to transfer that amount of power so you step out the voltage in order to reduce the current now there's a relationship between power current and voltage but imagine for a moment in your car you've got a 24 volt cable for batteries etc or a 12 volt cable these cables are actually quite thick now that's only for 24 or 12 volts but the reason they're thick is because they carry a high current so if you can step the voltage up and reduce the current then you can have thinner cables and this is a massive benefit if you've got hundreds of kilometres of cables so you can have thinner cables which means that you can save money in addition to that the losses that you'll have on your transfer grid or on your network will be lower if you step the voltage up so this is actually what we do and that's what the transformer does we'll step this up to say for example hundred and ten thousand volts 110 kV and it will then go through an open-air switch yard which is this area here and perhaps possibly another circuit breaker and then it will connect to the National Grid I can see it connect them to a pole there and that will go off into the distance connect to another transformer to step the voltage down again and we could use it for power in our homes such as for the dishwasher or the microwave so that's essentially our run-of-the-river power station works if you get a chance check out on the website I seriously think it's worth going around the model yourself and trying to figure out how it all works and how it's all put together if you liked the video please share it on Facebook or Twitter or any form of social media and if you really want to help us out please check out our patreon page thanks very much for your time

Channel: 3D-knowledge

Views: 18,160

Rating: 4.9288259 out of 5

Keywords: kaplan, pelton, francis, kaplan turbine, pelton turbine, francis turbine, hydroelectric turbine, how does a kaplan turbine work, pelton francis kaplan, run-of-the-river, hydroelectric power stations, run of the river, hydroelectric, run of river hydro plant, how run of river hydro power plant works, hydropower plant run of river, run-of-the-river hydroelectricity, hydropower, hydroelectricity, how hydroelectricity is made, hydropower (industry), renewable energy, green energy

Id: rm9JqQGDwN0

Length: 11min 7sec (667 seconds)

Published: Mon Nov 06 2017