Electric Power Quality Evaluation in the Presence of Electromagnetic Emissions Giovanni Cipriani, Rosario Miceli, Member, IEEE, Ciro Spataro Member, IEEE DEIM University of Palermo Palermo, Italy rosario.miceli@unipa.it; ciro.spataro@unipa.it Giovanni Tinè, Member, IEEE ISSIA National Council of Research (CNR) Palermo, Italy Abstract— The measurements for the assessment of the electric power quality are often carried out in hostile electromagnetic environments. The aim of the paper is analyzing if and how both radiated and conducted electromagnetic emissions can disturb the measurement system used to quantify these disturbances. To achieve the target, an experimental approach is proposed, which, by means of a simple and fast test, allows establishing if the real electromagnetic environment, where power quality analysis is performed, can alter the measurements. Keywords-electromagnetic immunity; power quality analysis I. INTRODUCTION In the electric power systems, determining and regulating the characteristics of both voltages and currents [1-5] is becoming more and more important, owing to the continuous increase of electric users susceptible to the variations of these characteristics respects to the rated ones [6-7]. In order to limit the injection of disturbances into the electric networks, there is the need to perform the evaluation of the so-called “electric power quality”; in many cases this evaluation is even prescribed by various national and international Standards and Laws. Obviously, the power quality analysis must be often carried out in the proximity of the disturbance injection points (e.g. high power nonlinear loads, photovoltaic systems, fuel cells and wind generators) [8-14], where there is a high chance to utilize the measurement instrumentation in a hostile electromagnetic environment. The target of the paper is to establish if this environment can perturb the measurement instrumentation and alter the measurement results. Due to complexity of the measurements, this kind of instrumentation is exclusively based on the analog-to-digital conversion of the electric signals and the successive processing of the acquired signals. In addition of the stand-alone power quality analyzers, more and more often, the measurements are performed using current and voltage probes, a general purpose data acquisition board connected to a common personal computer and processing (successively or in real time) the acquired data by using the computer processor itself [15-17]. This solution is less expensive respect to a stand-alone instrument and allows an easy updatability to the continuous variations of the rules prescribed by the Standards and the Laws concerning the electric power quality. For the “stand-alone” electric power analyzers, usually characterized by the manufacturers themselves from the electromagnetic compatibility viewpoint, it is quite easy obtaining information about the levels of conducted or radiated disturbances that can alter their performances. On the contrary, with regard to more complex measurement systems, which are constituted of various components provided by different manufacturers, the analysis of their electromagnetic immunity degree is not simple. Even having access to the electromagnetic compatibility data of each component, the extension of these specifications to the whole measurement chain is not completely straightforward. The whole measurement system has to be considered as unique equipment under test. Only in this way, a complete characterization of the system from the electromagnetic compatibility viewpoint can be carried out. To perform this characterization and to quantify the immunity degree of the measurement systems, it is necessary to choose one or more parameters that are representative of their performances and analyze if and how these parameters vary when the systems are subjected to electromagnetic disturbances. In previous works [18-20], we showed that the parameters, sufficient to characterize an analog to digital conversion based measurement system are offset, gain, the total harmonic distortion (THD), the total spurious distortion (TSD) and the signal to noise ratio (SNR). Therefore, we used these five parameters to assess the electromagnetic immunity of the considered measurement systems. In order to apply standard requirements and criteria for the immunity tests, we took into account the IEC-61236 standard [21] that specifies minimum requirements for immunity and emissions regarding electromagnetic compatibility for electrical equipment for measurement, control and laboratory use. We performed an extensive series of experiments on various configurations of systems, varying the typology, the shielding conditions, the relative and absolute position of each component of the measurement chain and varying typology, amplitude and/or frequency of the electromagnetic disturbance.   ,((( International Conference on Renewable Energy Research and Applications Madrid, Spain, 20-23 October 2013 ICRERA 2013 1145