Article sections
A voltage dip is a state during which the RMS voltage is lower than the user-defined voltage dip threshold. The basis for a voltage dip measurement is URMS(1/2), that is the one period RMS value refreshed every half period.
The voltage dip starts at the moment when the URMS(1/2) voltage decreases below the dip threshold value, and ends at the moment when the URMS(1/2) voltage is equal to or greater than the dip threshold value plus the voltage hysteresis.
The dip threshold is typically specified at 90{b7e1b70d923112b2dce5c7f61317ee3c713200fca463085e7ae47b1e4ec3e7da} of Unom. During the voltage dip, the power quality analyser remembers the minimum recorded voltage (this is called the residual voltage Ures and is one of the parameters characterising the voltage dip) and the average voltage value.