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Are there examples of how a failure at a power plant could affect the national grid? As mentioned by another comment, one advantage of a national power grid is

Are there examples of how a failure at a power plant could affect the national grid? As mentioned by another comment, one advantage of a national power grid is the ability to transfer power from other places during power failures. But I'm not sure how a power failure would affect the rest of the grid.

akiselev 5y ago
> Are there examples of how a failure at a power plant could affect the national grid? A failure at any single power plant is very unlikely to cause cascading failures in the rest of the grid because one power plant usually can't generate enough power relative to its grid. Gross oversimplification but all of the power plants in a national grid are essentially coupled together [1] as a giant circuit made up of a ton of electromagnets - the generators converting coal/natgas powered steam or water/wind to electricity. These electromagnets are all operating at the same frequency in phase with each other which literally means that the generators spin in sync at ~60hz. These generators are often (usually?) heavy turbines with a lot of angular momentum so normally when you connect a power plant, it stays in phase just due to the sheer inertia of the rest of the grid because power follows phase [2]. When the phase changes suddenly - like when connecting a generator that is out of phase with the grid - all that inertia of the generator essentially slams into the electromagnetic force generated by the incoming current. If the rest of the grid (of hundreds/thousands of other generators) produces significantly more power, it'll just destroy the connecting one as if you brought a turbine powered jet engine to an instantaneous dead stop - the momentum of the blades will literally rip them off of the shaft. However, if the newly connected generators are producing a significant amount of power relative to the rest of the grid, like when a corona mass ejection hits or a large islanded subgrid is poorly reconnected, the resulting differential can generate a wave (again, gross simplification) that travels through the grid with enough power to destroy every single generator connected to it. A single power plant just can't generate enough power to do damage to the rest of the grid [3] but if a natural disaster severed the connection between two regions of a grid and they drift out of phase, they must be carefully reconnected because they might have enough power to seriously damage other power plants. [1] Some parts of a grid might be separated by HVDC which in effect isolates the parts [2] Power flows from the faster generators to the slower ones, speeding them up until they hit equilibrium. [3] There are exceptions depending on grid topology, but generally grids are designed to avoid them

akiselev 5y ago

> Are there examples of how a failure at a power plant could affect the national grid? A failure at any single power plant is very unlikely to cause cascading failures in the rest of the grid because one power plant usually can't generate enough power relative to its grid. Gross oversimplification but all of the power plants in a national grid are essentially coupled together [1] as a giant circuit made up of a ton of electromagnets - the generators converting coal/natgas powered steam or water/wind to electricity. These electromagnets are all operating at the same frequency in phase with each other which literally means that the generators spin in sync at ~60hz. These generators are often (usually?) heavy turbines with a lot of angular momentum so normally when you connect a power plant, it stays in phase just due to the sheer inertia of the rest of the grid because power follows phase [2]. When the phase changes suddenly - like when connecting a generator that is out of phase with the grid - all that inertia of the generator essentially slams into the electromagnetic force generated by the incoming current. If the rest of the grid (of hundreds/thousands of other generators) produces significantly more power, it'll just destroy the connecting one as if you brought a turbine powered jet engine to an instantaneous dead stop - the momentum of the blades will literally rip them off of the shaft. However, if the newly connected generators are producing a significant amount of power relative to the rest of the grid, like when a corona mass ejection hits or a large islanded subgrid is poorly reconnected, the resulting differential can generate a wave (again, gross simplification) that travels through the grid with enough power to destroy every single generator connected to it. A single power plant just can't generate enough power to do damage to the rest of the grid [3] but if a natural disaster severed the connection between two regions of a grid and they drift out of phase, they must be carefully reconnected because they might have enough power to seriously damage other power plants. [1] Some parts of a grid might be separated by HVDC which in effect isolates the parts [2] Power flows from the faster generators to the slower ones, speeding them up until they hit equilibrium. [3] There are exceptions depending on grid topology, but generally grids are designed to avoid them