http://www.measurement.sk/M2013/doc/proceedings/075_Kralikova-1.pdf

This may help you.

Thank you

The measurement of grid quality parameters can be realized following IEC 61000-4-30 standard which describes “Power quality measurement methods”.

In the other hand, the limits defined by the standrad EN 50160 are described as: the total harmonic distortion in voltage, including up to 40th harmonics, needs to be lower than 8%. This is a restriction for any measurement instrument (network/grid/power analyzer) used to determine distortion power (D) from active (P), reactive (Q) power and apparent power as D=sqrt(S^2-P^2-Q^2).

Best regards.

Robert - Universitat Politècnica de Catalunya. Barcelona Tech

1. Power Factor and Distortion Measuring for Small Loads Using USB Acquisition Module

Marko Dimitrijević,vančo Litovski

LINK: http://leda.elfak.ni.ac.rs/people/marko/articles/Power%20Factor%20and%20Distortion%20Measuring%20for%20Small%20Loads%20Using%20USB%20Acquisition%20module.pdf

and

2. Computer Based Power Factor and Distortion Measuring for Small Loads

Marko Dimitrijević and Vančo Litovski

LINK: http://leda.elfak.ni.ac.rs/people/marko/articles/Computer%20Based%20Power%20Factor%20and%20Distortion%20Measuring%20for%20Small%20Loads.pdf

Abstract

- Power factor and distortion measuring usually requires dedicated and expensive equipment. Computer-based acquisition modules and software provide for a possibility to create simple and non-expensive methods and instruments for power factor measurement and distortion characterization of small loads and bring all advantages of virtual instrumentation. A new

approach to power quality characterization by measuring power factor, distortion and several other parameters of small electric loads (up to 0.5kW) will be described in this paper. Besides the low price maximum versatility and adaptability is provided without any loss in accuracy.

Keywords –

Power factor, distortion, virtual instrument

3 National Instruments Tutorial(in attachment)

Harmonic Distortion Measurement

Publish Date: Feb 02, 2012

Overview

Harmonic distortion is a measure of the amount of power contained in the harmonics of a fundamental signal. Harmonic distortion is inherent to devices and systems that possess nonlinear

characteristics—the more nonlinear the device, the greater its harmonic distortion.

P.S.

Very instructive!

Dear Ivan,

First of all, we should think about the definition of distortion power.

Here a thesis very interesting about this subject :

http://theses.ucalgary.ca/handle/11023/1037

Best Regards

I think IEC 61000-4-30 standard is very useful.

Distortion power D is a component of the total non-active power Q, but it is not orthogonal to the other components of apparent power S, with the result that S cannot be uniquely defined. If non-active power is to be separated into components, then the components must be orthogonal to each other and to P. Two orthogonal components of Q with practical realisation have been defined rigorously and consistently in both the instantaneous and average domain. I recommend for your consideration an IEEE Transactions paper (2008) and three EPSR papers (2011, 2012 and 2013) by Malengret and Gaunt, and a conference paper that is easier to read (IEEE PowerAfrica, 2012) and is a useful introduction to the general power theory.

Refer to IEEE 519.

The power quality is an important issue in T&D. It increases the losses and reduce life span of diferent componnets and devices connected to power system. Total harmionic distortion (THD) can be measured with power analyser (Fluke).

Distortion power, as another colleagues have already described, is a power component, it is a part of the apparent power, affects power factor and its presence is raleted to different affections on the electric system. IEEE std 1459 has presented a quite complete and interesting description on the topic. From my opinion, the question about the necessity of measuring D could be different: why is it not measured? An interesting answer is that most energy revenue metters cannot measure it, then if it needs to be measured the cost of replacing metters would be prohibiting. Several electronic revenue metters and some PQ analysers are able to measure D, such information can be used to improve PQ analysis. Regarding how to measure D, IEEE STD 1459 suggests some ideas, I would also suggest to measure power based on voltage and current measurements according to IEC std 61000-4-7.