Components of Admittance. ( Simple Explanation)

Electrical Technology

Components of Admittance.

Conductance:

A component of admittance inphase with the applied voltage is called conductance. Or the X component of admittance is called conductance. It’s represented by G and the unit of conductance is Mho or Siemens.

G = Y Cos φ = (1/Z) * (R/Z) = R/Z² = R/ (R² + X²)

(Since Cos φ = R/Z and Y = 1/Z)

And Total Conductance G_T= G₁ +G₂ +G_3+…..

Susceptance:

That component of admittance, which has an angle of 90 degree with applied voltage is called suserptance. ..or Y component of admittance is celled susceptnce, its represented by B. and the unit of susceptance is also Mho or Siemens.

A Component of admittance in quadrature ( at 90 degree) with the applied Voltage is called susceptance.

B = Y Sin Φ = 1/Z * X/Z = X/Z²= X/ (R²+ X²) ——–> (Since Sine Φ = X/Z)

And total Susceptance = B_T = B₁ + B₂ + B₃ +…B_n

Also Note that inductive suseptance of a circuit is negative (-), while Capacitive Susceptance of a circuit is always positive (+).

Y = G – j B_L …… (In case of inductive Circuit)

Y = G + B_C……. (In case of capacitive circuit)

For More explanation, consider the following circuit, (fig 1)

The Total conductance = algebraic sum of the conductance in each branch.

The Total conductance =G_T= G₁ +G₂ +G₃

Similarly,

Total susceptance = algebraic sum of the susceptance in each branch,

Total susceptance B_T = (-B₁) + (-B₂) + (B₃).

And total circuit admittance,

Y_T = √ (G_T² + B_T²)

In case of inductive Circuit Y_T = √ (G² + B_L²) and Phase angle φ tan^-1 (-B_L/G)

In Case of Capacitive Circuit Y_T = √ (G² + B_L²) and phase angle φ tan^-1 (B_c/G)

And Total current, I = VY,

And Power factor = Cos φ = G/Y.
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