2.60 P_SG1 P_SG2 (MVar) (MW) 2.40 2.20 2.00 x 1.20 1.10 1.00 Q_batt 100 50 0 -50 -100 20 60 min = 6 h = 13 Q_SG2 0.90 P_batt (kVar) (kW) 1.80 300 200 100 0 -100 -200 -300 Q_SG1 1.30 100 140 180 220 260 x 20 60 min = 6 h = 13 100 140 180 220 260 Periods of Primary and Secondary Control figure 8. The real and reactive power dispatch of DER units in Case 2. 300 P_batt (kW) 200 x 200 100 Change in Dispatch by Tertiary Control 100 0 0 -100 -200 -100 h = 13 Q_batt 4.0 6.0 min = 33 x 8.0 10.0 12.0 14.0 16.0 18.0 20.0 4.0 h = 13 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 min = 33 figure 9. The real and reactive dispatch of battery storage during load restoration in Case 2. Freq_microgrid 9.00 4.48 (MW) (Hz) 60.40 60.20 60.00 59.80 59.60 (MVar) (kV) 8.00 4.50 4.16 4.00 3.84 h = 13 Load Restoration by Tertiary Control 7.50 V_pcc 4.32 x 8.50 P_Load 4.25 Q_Load Load Restoration by Tertiary Control 4.00 3.75 3.50 4.0 6.0 min = 33 8.0 10.0 12.0 14.0 16.0 18.0 20.0 x h = 13 (a) 4.0 6.0 min = 33 8.0 10.0 12.0 14.0 16.0 18.0 20.0 (b) figure 10. The load, voltage, and frequency of the IIT microgrid during load restoration in Case 2. (a) The periods in which the microgrid voltage and frequency are adjusted by the master controller. (b) The total served real and reactive load on campus. immediately after islanding, the master controller provides emergency demand response in order to prevent a sustained drop of microgrid frequency and voltage as the natural gas turbine is faced with a ramping limit. the master controller will send load curtailment 78 ieee power & energy magazine signals through tertiary control to building controllers to curtail the campus load from 11.07 MW and 5.54 Mvar to 4.13 MW and 2.07 Mvar (the amount of load supplied by the natural gas turbine and solar Pv and wind unit before islanding). january/february 2014