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Electric Power Systems Exam #5: 19/02/2021 1° Part Exercise 1 Consider a generation plant made of two identical synchronous machines connected in parallel to the plant terminals as shown in the figure bellow, where 𝑃𝑝𝑙 and 𝑄𝑝𝑙 are the total real and reactive power, respectively. Each synchronous machine is characterized by: Nominal apparent power 30 MVA Nominal operating voltage (line-to-line) 15 kV Phase synchronous reactance 21 Ω Maximum turbine mechanical power 26 MW emf 𝐸0 (phase-to-ground) at maximum excitation current 10 kV Stator windings connection Y (star) In normal operating conditions the voltage at the plant terminals is equal to the nominal volta ge of the synchronous machines, while SG1 is operated with an emf of 𝐸01 = 9.2 𝑘𝑉 and a load angle of 𝛿1 = 15 + 𝑵° and SG2 is operated with an emf of 𝐸02 = 7.2 + 0.1 ∙ 𝑵 𝑘𝑉 and a load angle of 𝛿1 = 0°. 1. compute the total active (𝑃𝑝𝑙) and the total reactive power (𝑄𝑝𝑙), respectively, supplied by the plant to the external network Ext Net; 2. compute the emf (𝐸0) and the power angle (𝛿) for each of the two synchronous generators of the plant when the two are equally loaded; 4. for the operating conditions identified at point 2 check the capability limits for both sync hronous generators of the plant; 5. considering the operating conditions identified at point 2 determine the maximum reactive power that the plant can supply to the external network. In the above data, N is the last number of the student’s Person Code/Codice Persona (e.g. if Person Code is 10381486 then N = 6); Please substitute accordingly. Exercise 2 Consider the following electrical network Line xl [pu] L1 0.035 L2.1 0.02 L2.2 0.015+0.05∙ 𝑵 Generator G Real power output: PG Operating voltage: VG [pu] [pu] G 10 0.98 Demand D Absorbed apparent power:…