Multi-terminal Direct-Current Grids: Modeling, Analysis, and Control

3.3 AC Grid Model

In the previous section, modeling of an MTDC grid was described considering voltage source representation of AC grids. In this section, modeling of an AC grid comprising generators, exciters, loads, etc. is presented. This would lead to a combined AC–MTDC model which is essential for planning and operation of future power systems. Although the dynamic modeling of an AC grid is well understood, we will very briefly review this topic for completeness. It should help the readers obtain a comprehensive picture of the integrated AC–MTDC system model.

In power systems, the primary sources of electrical energy are the synchronous generators. The problem of power system stability is primarily to keep the interconnected synchronous machines in synchronism [12]. Their stability is also dependent on several other components such as the speed governors, excitation systems of generators, loads, FACTS devices, etc. Therefore, accurate understanding of the characteristics and modeling of these components are of fundamental importance for stability studies and control design. The general approach to modeling of several power system components is quite standard. A quick overview of these models is given in this chapter. For further details, the readers are referred to [12, 38].

3.3.1 Generator Model

Accurate modeling of the synchronous generators and their excitation systems is of paramount importance for studying the dynamic behavior of AC power systems. Although today's ...