Civil Engineering Reference
In-Depth Information
FIGURE 14-11
Thevenin's equivalent circuit model of the grid and wind farm for evaluation of the grid
interface performance for evaluating the system stiffness at the interface.
Mexico, engineers are faced with locating sites that are also compatible for
interfacing with the grid from the power-quality point of view. The basic
consideration in such decisions is the source impedance before and after
making the connection. Another way of looking at this issue is the available
short-circuit MVA at the point of the proposed interconnection, also known
as the system stiffness or the fault level.
14.8.1
System Stiffness
One way of evaluating the system stiffness after making the interconnection
is by using the Thevenin's equivalent circuit of the grid and the renewable
plant separately as shown in
Figure 14-11
.
If we let:
V = network voltage at the point of the proposed interconnection.
Z
i
= source impedance of the initial grid before the interconnection.
