Power quality analysers from different manufacturers produce different flicker values
In order to measure flicker correctly a power quality analyser’s hardware and software must both be properly designed.
Papers presented by various sources have also shown that power quality analysers from different manufacturers more often than not produce different flicker values when measuring the same signal.
In view of this the Venezuelan Ministry of Energy and Mines and the utilities ENELVEN, ENELDIS, ENELCO, ELECAR and ENELBAR decided to arrange a comparative flicker measurement test, and invited manufacturers of power quality instruments to participate with their respective analysers.
The following manufacturers / power quality analysers participated in the test:
- Unipower / Unilyzer 902
- AMETEK / Meridian Quatro
- LEM / TOPAS 1000, MEMOBOX 300smart “P” and MEMOBOX 300smart “A”
- Square D / PowerLogic PM850
- ECAMEC / RES4R32A-3P
- Power Measurement / ION 8500
The analysers were connected in parallel to the same flicker source. Thus all of them measured the same signal, and a number of tests generating different flicker values were performed and evaluated.
Among the conclusions made from these tests were:
Analysers from different manufacturers with IEC 61000-4-15 certification did not produce the same flicker (Pst) values when measuring the same signal.
Unipower’s Unilyzer 902 was the only analyser that produced flicker values that complied with the established test protocol / limits for all of the valid tests.
Three of the other analysers produced values, but did not comply.
Two of these analysers were from the same manufacturer, but the units still presented different flicker values when measuring the same signal.
The other four participating analysers did not produce any valid results.
Measuring just the voltage change (ˆ†V/V) is not sufficient to determine the existence of a flicker problem.
This is the graph with the results from the tests: