Summary
International Symposium on Electromagnetic Compatibility
2009
Session Number:23R1
Session:
Number:23R1-2
Contribution of Impedance Imperfection of the V-type LISNs in Measurement Uncertainty of Conducted Disturbances
R. Bąbka,
pp.541-544
Publication Date:2009/7/20
Online ISSN:2188-5079
Summary:
EMC standards require measurement of conducted disturbances emitted via cord to the mains. For the benefit of measurements reproducibility the standards define so called V-type Line Impedances Stabilisation Network which is inserted into the mains. Deviation of LISN impedances from that of the reference LISN contributes to measurement uncertainty. Approach for estimation of this contribution is presented in CISPR16-1-2 and CISPR16-4-1. Simplified EUT model with only one electromotoric force and only one impedance is considered there. In CISPR16-4-2 this approach is used for uncertainty estimation with assumption of impedance tolerances. In this paper complex EUT model with one differential mode source and two common mode sources is considered. Elaboration is accomplished with two estimations: ? for specific LISN for which impedances are measured with vector network analyser, ? with assumption of tolerances imposed on the LISN impedances. The paper proves the advantage of uncertainty calculation for individually measured LISN impedances, compared with application of the impedance tolerances. Investigation of the authors shows that results of uncertainty distribution can contain mean value unequal to zero. In document CISPR16-4-2 this fact is ignored. It is recommended there to symmetrise the range of variation in case of unsymmetry. The authors oppose this approach.