Page 447 - Decision Making Applications in Modern Power Systems

406 Decision Making Applications in Modern Power Systems

Fig. 15.8A D by dotted lines), and cycle-based load (refrigerator) oper-
ates with the control cycle mode (with a small switch “ON” time, i.e.,
15 minutes “ON” time at the place of 30 minutes “ON” time) as shown
in Fig. 15.9A by a dotted line.
Mode IV: PV and SOC higher (prescheduling of deferrable load):
During 17:41 18:10 hours time interval the PV generation is higher
than the building demand (demand with a conventional scheme and
future deferrable load, i.e., pump), and the battery SOC is higher than
the desired. In addition, the task starts and completion time limit (even-
ing time) for the pump is 17:30 19:30 hours, and the operating time is
30 minutes. In the DSM scheme the microcontroller switches “ON” the
pump at the time instant 17:41 and keeps it “ON” during 17:41 18:10
hours as shown in Fig. 15.9C. The surplus PV generation is stored in
the battery.

15.6.2 Performance results of demand-side management scheme
with insufficient photovoltaic power
In this case the PV energy generation is sufficient enough to fulfill the build-
ing energy demand for a particular day. Therefore the proposed DSM
scheme is load shedding noncritical load and operates the cycle-based load
in a “control cycle mode” to achieve a desired SOC of the battery storage
unit. The building power demand curve with the conventional scheme, DSM
scheme, and the PV power generation for a typical day is shown in
Fig. 15.10. The peak demand of the building is 297 and 220 W with conven-
tional and DSM schemes, respectively. The battery charging and discharging
power curve with conventional and proposed DSM scheme for this scenario
is shown in Fig. 15.11. The peak discharging power of the battery is 327 and
243 W with conventional scheme and DSM scheme, respectively, during
nonsunny hours. It shows that the small size of the battery is sufficient with
the DSM scheme to supply the peak load of the building during nonsunny
hours.
The state of the charge of the ES with the conventional scheme remained
higher than the desired level, excluding the 06:00 12:20 hours as shown in
Fig. 15.12. The DSM scheme achieves desired SOC of the ES unit by shift-
ing the operating hours of the deferrable load to achieve the desired SOC.
The operating duration of the washing machine has been shifted from
07:00 08:30 to 10:35 12:10 hours time interval as shown in Fig. 15.13B.
The morning operating time of the water pump has been postponed from
08:00 08:30 to 12:10 12:40 hours time interval and evening operating time
of the water pump is proponed from 19:05 19:35 to 17:45 to 18:15 hours
and as shown in Fig. 15.13C. The refrigerator operates in the “regular control
mode” same as conventional scheme as shown in Fig. 15.13A. The SOC of
the ES unit is achieved by controlling the deferrable load of the building;