说明：  A Discrete 3-Phase ProgrammableSource block is used to generate a 1 pu, 15 degrees positive sequence voltage. At t = 0.05 s the positive sequence voltage is increased to 1.5 pu. At t = 0.1 s an unbalance is introduced by adding a 0.3 pu negative sequence component with a phase of -30 degrees. The magnitude and phase of the positive-sequence component is evaluated in two diiferent ways: 1) Sequence calculation of phasors using Fourier analysis and 2) abc to dq0 transformation. Math Function and Trigonometric Function blocks are used to evaluate the magnitude and phase of the positive sequence from the d and q components: V1 = sqrt(Vd^2 + Vq^2) , Phi1 = atan(Vq/Vd))