Nonlinear Controller of Synchronous Generator Set Using Only Local Measurements

Because the generator set model applicable to transient stability analysis is not suitable for the designing of nonlinear controller using only local measurements, it is modified into a new kind of model, or structural model of generator set, firstly. The structural model includes differential equations, interface equations and interface variable set. Based on the interface variable set, local measurements at the terminal of generator (such as the reactive and active power, terminal current and voltage) can be chosen to describe the relationship between the generator set and the AC grid. Furthermore, based on the interface equations, the relation between the terminal measurements and the immeasurable variables in the differential equations of generator (such as the d and q-axis stator circuit currents, the transient EMF in the q-axis) can be established. Thus, it is easy to transform the immeasurable variables into local measurements, and then the nonlinear controller using only local measurements can be designed easily. In the paper, ANN-inversion method is used to design the nonlinear controller, and the simulation results of a two-area four-machine power system demonstrate its validity