Two 50 Hz generating units operate in parallel within the same plant with the following ratings:
Unit 1 : 500 MVA, 0.8 pf, 13.2 kV, 3600 rpm, H = 4 mJ/MVA
Unit 2 : 1000 MVA, 0.8 pf, 13.8 kV, 1800 rpm, H = 5 MJ/MVA
For a base of 100 MVA, which of the following statements is/are true if two machines swing coherently?
1
Inertia constant of unit 1 is H1 = 20 MJ/MVA
2
Inertia constant of unit 2 is H2 = 0.5 MJ/MVA
3
Inertia constant of the system is Heq = 14.28 MJ/MVA
4
Inertia constant of the system is Heq = 70 MJ/MVA