Phasor diagrams

This is the difference in phase between the primary and the secondary voltage phasors (S). The direction of the phasors are so ehosen. that the angle is zero for i perfect transformation. Refer to Ihe phasor diagram. Figure 15.2. and Table 15.5 for measuring and Table 15.6 for protection VTs. 

Note The phasor diagram is drawn taking the applied voltage I/, as the reference phasor. It can also be drawn taking the primary induced emf V as the reference. The logic to the diagram and the subsequent results shall however, remain the same. 

Consider a ground fault on phase R. The voltage across this phase will become zero and the phasor diagram will be as illustrated in Figure 15.5(b). The other two phasors will remain the same as in a healthy system and add to give the residual voltage F, i.e. 

Refer to the phasor diagram in Figure 15.18 and Table 15.8 for measuring and Table 15.9 for protection CTs. This error can also be expressed by... 

For ease of illustration, all these parameters have been drawn in the phasor diagram (Figure 16.4). To select the rating of the synchronous condensers, consider their average efficiency,... 

Figure 16.7 Phasor diagrams for QDC, referred to the secondary side of the control transformer...

A phasor diagram (Figure 23.18(c)) illustrates the reduction in the actual loading and enhanced load transfer capacity of the network which can be achieved with the help of harmonic suppressions. For even better utilization, the system may be tuned for higher harmonic disorders also. 

Figure 24.5 Receiving-end voltage phasor diagram on load, in an uncompensated line...

Figure 24.6(b) Phasor diagram of the series compensated system... 

The receiving-end voltage rises with leading p.f.s and droops with lagging. This is illustrated with the help of phasor diagrams (Figures 24.22(a) and (b). 

We could thus represent these two moduli on a phasor diagram as shown in Fig. 2.54. El leads 2 by 90° (tt/2 radians) and from this diagram it is possible to define a complex modulus, E where... 

Fig. 2.54 Phasor diagram showing complex modulus ( ) relative to loss ( 2) and storage ( 1)...

Figure 16.6 illustrates the phasor diagram applicable to power factor correction. 

Fig. 5.18. Phasor diagram for the components of the SH polarizability as a function of thallium coverage (0) on Ag(l 10) where ae10 = Zj = x z Skl Fjklxffi and Fjkl are the Fresnel coefficients. Incident wavelength = 1064 nm. Solid lines are vectors representing ]/7sh, anc phase, A

Let s now consider an inductive circuit where application of voltage V produces current I as shown in Figure 6.2 and the phasor diagram for a single-phase circuit is as shown. The current is divided into active and reactive components, /P and /Q ... 

FIGURE 6.9 Schematic and phasor diagram showing voltage rise due to capacitive current flowing through line impedance. 

Important relationships can be derived by reference to the wound toroid (Fig. 9.3(a)) where the current I is now regarded as sinusoidal and represented by /0exp(j ut). The appropriate phasor diagram is shown in Fig. 9.5. If the instantaneous current is I, the corresponding field is nl and the flux linking the circuit is p. n2IAl. For a current varying sinusoidally the e.m.f. is... 

Fig. 9.5 Phasor diagram showing the components of the voltage U in phase and out of phase with the driving current I.

In an Argand17 diagram representation of Z, called a phasor diagram, 8 is the angle by which the current I(t) lags the voltage V(t). The reciprocal of the impedance Z is the admittance Y ... 

The relationship between the complex impedance and the phase angle is shown more clearly in the use of phasor diagrams and relationships. The impedance can be expressed as... 

It is instructive to represent power in an a.c. system via a phasor diagram, as shown in Fig. 10.4. In this representation, the product VA, has a projection on the abscissa (real or power axis) and on the ordinate (quadrature, reactive power, or VAR axis), and the following relationships apply ... 

The relationship between two phasors at the same frequency remains constant as they rotate hence the phase angle is constant. Consequently, we can usually drop the references to rotation in the phasor diagrams and study the relationships between phasors simply by plotting them as vectors having a common origin and separated by the appropriate angles. 

Figure 10.1.4 Phasor diagram showing the relationship between alternating current and voltage signals at frequency o).

Figure 10.7.1 Phasor diagram showing the relationships between the faradaic (7f) and capacitive (7 c) components to the total current (7). Note that 7f has a component along Fac, whereas I does not.

The following points apply to the drawing of phasor diagrams of generators and motors... 

Each reactance and resistance in the machine has a volt drop associated with it due to the stator current flowing through it. Consider a generator. The following currents and voltages can be shown in a phasor diagram for both the steady and the dynamic states. 

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