Two power system areas are interconnected and have following regulation (R) and rated power (Pr) values: Area1: R =5%, Pr =1000 MW and Area 2: R =6%, Pr =800 MW. Determine the steady changes in frequency, tie-line powers and generations when the load demand in area-2 increases by 100 MW. Also analyze the effect of connecting another area-3 (R =4%, Pr =500 MW) on the steady changes in frequency, generation and tie-line powers following the same load changes as above. Comment on the results obtained. Assume free governor operation and rated frequency of 50 Hz.