Case study 2

   Although in the case 1 the problem tends to be solved increasing the reactive power compensation, there is some uncertainty about the time available to take this control action. Moreover, as the process is simulated in a cuasi-dynamic way, taking into account  different  load  behaviour models for different instants of time, it is not possible guarantee the system stability, even though a solution exists in the steady state analysis.

Consequently, the voltage stability is a problem that in many cases must be studied in a dynamic way, so the characteristics of load and reactive power control devices models are of key importance, which depend on the study horizon to analyse (short and long term). 

In this case a study in the short-term has been carried out considering a short-circuit in the middle of one of the lines (large disturbance). Therefore, the power system studied has been modelled taking into account the following considerations:

Fig. 3.- Study network for case 2

Problem Solution :

Fig. 4.- Voltage stability short-term dynamic analysis for the network of Fig. 3

Theoretical details:

The full theoretical details of the proposed solution are free available in a pdf file

Software developed :

The free available Simulink program was implemented to solve the problem