[1][2] This ratio can also be expressed as an inverse of the saturated[3] direct-axis synchronous reactance (in p.u.
[9] A stiff machine has a higher SCR, is more loosely coupled to the network and thus is slower in following.
A less stiff machine with lower SCR (a typical situation for modern h=generators) will follow the grid faster.
[8] The larger the SCR, the smaller is alternator reactance (Xd) and inductance Ld.
This reduces the machine's stability while operating on the grid and will reduce the short circuit current delivery capability (lower short circuit current), smaller machine size, and lower cost subsequently.