The basic thinking of custom modeling method is: the
user can accord to their actual needs, and rely on the new
established model or model from model library. The linear
state equations of any one component can be expressed as
model structure diagram with the five basic models, which is
linear frame, integral frame, inertial frame, inertia and
differential frame and shift frame. The system model is
described by modules, the relationship among models
denotes by line, a output of one model is the input of another
model. Give a custom modeling method applied to low
frequency oscillation analysis, the model diagram as shown
in figure 5.