It is defined as the dielectric loss expressed as the tangent of the angle between the reactance and the impedance vectors of the capacitor, it is denoted by D.
FACTORS AFFECTING DIELECTRIC LOSS:
(1)The loss increases proportionately with the frequency of applied voltage.
(2)Presence of humidity increases the loss.
(3)Temperature rise normally increases the loss.
(4)Voltage increases because increased dielectric loss.