Voltage Fluctuations (Dips & Swells) - When and How to Measure [Demo]

Voltage fluctuations (dips and swells) can be measured on two bases:

- Slow fluctuations with an RMS value formation over 200 ms each
- Fast fluctuations with an RMS value formation over 10 ms each


When Do I Measure and Which Type of Measurement Do I Use ?

The 200 ms measurement is used for long-term monitoring, even if there are no interferences. This is typical for measurements against the EN 50160 standard.


How Do I Measure According to EN 50160?
=> Measuring Practice EN 50160

The 10 ms measurement mode is also used for measurements according to EN 50160, but its main function is the search for disturbances. When looking for disturbances, the "fast voltage fluctuations" measurement type should be used, thus the flicker is also detected.


How Do I Measure Slow Voltage Fluctuations?

See Fluke 435 Voltage Current Frequency (Volts/Amps/Hertz) Menu or Fluke 435 II Voltage Current Frequency (Volts/Amps/Hertz) Menu


How Do I Measure Fast Voltage Fluctuations?

See Fluke 435 Voltage Fluctuations (Dips and Swells)  Menu or Fluke 435 II Voltage Fluctuations (Dips and Swells) Menu.


Can I Measure Both Parameters Together?

Yes, this is possible, using the Fluke 435 Menu Long-Term Recording (Logging) Individual Parameters Fluke 435 II Menu Long-Term Recording (Logging, Logger Function) .

Now proceed as follows to eliminate the problem: Connect the voltage circuit of the power quality analyzer with the feeding main- or sub-distribution. Each outgoing line is now briefly recorded individually with the current clamp. If the trend curves for current and voltage run in the same direction, the fluctuation comes from the supply side (voltage drop causes current drop and vice versa). Therefore, the search within one higher distribution level is recommended or a neighboring outgoing line should be examined. If the trend curves run in opposite directions, the cause is on the consumer side (rising current causes voltage drop and vice versa). In this case, the search within one lower distribution level is recommended. Due to the tree structure of the power grid, the fault location can be found quickly and clearly .

I have results of my voltage-fluctuation measurement; how do I know what to do next? See Remedy for Voltage Fluctuations (Dips and Swells)