Fluke 435 user manual Dips & Swells, Characteristics of a voltage dip

Chapter 9

Dips & Swells

Introduction

Dips & Swells records Dips, Interruptions, Rapid Voltage Changes, and Swells.

Dips (Sags) and Swells are fast deviations from the normal voltage. Magnitude may be ten up to hundreds of volts. Duration may vary from a half cycle to a few seconds as defined in EN61000-4-30. The Analyzer allows you to choose nominal or sliding reference voltage. A sliding reference voltage uses measured values filtered with a 1- minute time constant.

During a dip the voltage drops; during a swell the voltage rises. In three phase systems a dip begins when the voltage on one or more phases drops below the dip threshold and ends when all phases are equal to or above the dip threshold plus hysteresis. The trigger conditions for dips and swells are threshold and hysteresis. Dips and swells are characterized by duration, magnitude, and time of occurrence. Figure 9-1 and 9-2 explain this.

Figure 9-1. Characteristics of a voltage dip

9-1