What would be the voltage regulation if there is capaciyicve load?

When dealing with a capacitive load, the voltage regulation of a transformer behaves differently compared to inductive or resistive loads. Here are the key points:

Voltage Increase

Under a capacitive load, which has a leading power factor, the secondary terminal voltage of the transformer tends to increase rather than decrease. This is because the current leads the voltage by 90 degrees, which contrasts with inductive loads where the current lags the voltage245.

Negative Voltage Regulation

The voltage regulation in this case is considered negative. This is expressed by the formula for voltage regulation, where the difference between the no-load voltage ((V_n)) and the full-load voltage ((V)) is calculated. For a capacitive load, (V > V_n), leading to a negative regulation value:

[ \text{Regulation} = \frac{V_n - V}{V_n} \times 100\% ]

Since (V > V_n), the regulation will be negative34.

Mathematical Expression

The mathematical expressions for voltage regulation under a capacitive load can be derived from the general voltage regulation formula, taking into account the leading power factor. For a capacitive load, the expression involves the reactance and resistance drops but with a negative sign due to the leading power factor:

[ E_2 - V_2 = I_2R_2 \cos\theta_2 - I_2X_2 \sin\theta_2 ]

Here, (E_2) is the no-load secondary voltage, (V_2) is the full-load secondary voltage, (I_2R_2 \cos\theta_2) is the resistance drop, and (I_2X_2 \sin\theta_2) is the reactance drop. The negative sign indicates that the voltage increases under a capacitive load24.