*3.1. Evaluation of Power Losses for a Single Shaded Panel*

In the following part three cases are evaluated: case 1, only a line has been interrupted; case 2, two lines were interrupted; case 3, the whole panel is shadowed. By excluding the shaded panels there will be 16.7% of losses. DRS can enable the power increases shown in Table 11.


**Table 11.** Electrical Characteristics in different loading conditions evaluated by reconfigurator for each panel.

Data presented in Table 11 can be plotted in Figure 11: in case 1 and for the lower currents (load A, B and C) there is an increase of power, for higher currents (loads D and E) there is a decrease; in case 2, for lower currents (loads A, B, C and D) there is an increase, for the higher current (load E) there is a decrease.

Case 3 is now considered: the shadow cuts entirely the panel, as shown in Figure 8. A negative voltage of the shadowed panel affects the performance of the string. Each not shaded panel varies its operating condition assuming a voltage slightly higher than the non-perturbed, to compensate the voltage drop on the shaded panel and to try to maintain a high current. Table 12 shows the increase of power when a panel is totally shaded. The study of case 3 shows that when the shadows cuts in two parts the panel 6 and it becomes a load, reconfiguration reduces always the loss of power.

**Figure 11.** Zones of convenience of the disconnection of shaded module.


**Table 12.** Characteristics in different load conditions evaluated by reconfigurator for each panel.

Case 3 shows the real performance of the DRS. Between loads C and D the maximum power point is performed. By considering the overall behavior of two shaded strings used simultaneously, a possible performance increase between 12 and 25% can be expected.
