What Is the Ground in a Power Plant Schematic?

[LAP3141]

TL;DR

What is the basic schematic for an electric power generation plant?

A power generation plant converts chemical (or nuclear) energy into electrical energy. This energy is then sent out via conductive transmission line.

What would be a simple schematic for this process?

That is, if we liken it to a battery, then the positive pole would be the high voltage output line, but what would constitute the ground?

Is the return path, or ground, of a power plant literally the physical earth?

 

[berkeman]

What research have you done so far on this? It's pretty easy to find such information via Google and looking at the Wikipedia article(s).

Also, is this question for schoolwork, or general interest?

 

[berkeman]

BTW, there is a good set of PF Insights articles about the power grid:

https://www.physicsforums.com/insights/ac-power-analysis-part-1-basics/#toggle-id-1

 

[Babadag]

See also-for instance:
ELECTRIC POWER distribution handbook by T.A. Short

 

[isquaredr]

Hello, I work in the maritime industry, here is a simple thought schematic of our power generation:

We have 3 diesel generators that are started by a pneumatic powered motor to turn the shaft(like a battery starter for your motor). For the sake of discussion let us pick out 1 generator and how it distributes power to the ship, let us first suppose that you already have another generator running that supplies power to the controller of generator for starting.

1. Generator is started by air to help the shaft turn, then fuel is introduced for internal combustion to take over the power generation.

2. The generator stator windings, as is common, is wired in a Wye connection, where the three phases(L1, L2, and L3) meet to a common point that we use and call as Neutral point(N). , the neutral point is connected through a resistor to the ground(we call this resistor as the Neutral Grounding Resistor), the ship's ground is usually the hull surface or the metal hull. Relevant to your question, generation plants connect to the physical Earth as their ground.

3. These stator wires run all the way up to the generator ACB(Air circuit breaker), then, once the generated voltage and frequency and other parameters has been stabilised, they connect to our busbar as L1, L2, L3, and N.

4. The generator parameters are continuously being monitored by a controller that maintains the generator speed to regulate a constant voltage and frequency output, the controller is responsible for determining how much fuel is needed for the generator to supply the demanded load.


>>>>Is the return path, or ground, of a power plant literally the physical earth?
Return path ideally should never be ground as it is called a ground fault(where one of the live lines come in contact with anything other than intended, for example the one of the supply lines to a motor comes in contact with its body), ground faults are avoided as it poses risk of electrocution to personnel.

Power generation tends to get more complex as more generators are being operated in a parallel connection to a grid, as you have to monitor and take into account more parameters to ensure a reliable power supply to the grid.

 

[Babadag]

Usually a power generation station [ or a power plant] electric schematic diagram it depends on the power delivery level. A power plant-diesel motor driven from 100 to 5000 hp -from one unit to 10 units-depending on local ,regional or national grid necessities.

The schematic diagram- usually on low voltage- is very simple.
With the increase of the produced power the scheme becomes more complicated.
From 10 MW to 300 MW gas turbine driven generators- usually two generators per one power station unit.

The gas turbine fuel is diesel oil pulverized and turned into gas.
From 300 MW up to 800 MW- twins usually-steam gas or coal fired turbines.
Some time the gas supplied it is a secondary product of other main product as in a steel plant-for instance-from furnace for cast iron production.

I worked- for a while- in such big steel product manufacture, where was 4x100 MW turbine supplied with furnace gas for the steel production .

The plant yard was 10000 ft length and 3000 ft wide. A central substation of [110 kV] 40 switchgears was connected with 13 substations of 2*40 MW each by means of 40 km 110kV cables [oil-circulating paper insulated, 1500 kcmils copper conductor]. The main supply source was the 400/110 kV national grid connected with central substation with two overhead transmission lines.

The schematic diagram it depends on power delivery level and many other conditions

If you have in your mind a concrete example, I will be glad to try to concept a diagram.