Model is underconstrained.
The following variables couldn't be defined:
 * VA in component equations
 * delta_PL in component equations
 * PL in component equations
 * foi in component equations
 * qi in component equations
 * fci in component equations
 * d/dt PA in component equations
 * d/dt PL in component equations
 * d/dt fo in component equations
 * d/dt fc in component equations