What are the Di parameters in the power grid model?

The $D_{i}$ parameters in the power grid model are the damping coefficients for the different rotors; there is a typo in the equations, as each rotor has its own damping coefficient (the first equation notation is $D_{1}$, the second has to be corrected to $D_{2}$).

--Elisa 15:11, 8 October 2007 (PDT)