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Control and limitation of harmonic current emission from new customer installations is essential for maintaining supply voltage distortions below the prescribed compatibility or planning levels, and is also required for ensuring electromagnetic compatibility. At the planning stage, emissions of low-order harmonic current are evaluated based on several assumptions and simplifications related to, e...
This paper presents the results of experimental evaluation of interharmonics produced by PV inverters (PVInv) for a range of different operating conditions. First, intrinsic interharmonic generation due to Maximum Power Point Tracking (MPPT) control is analyzed. Afterwards, generation of current interharmonics assessment is analyzed adopting the IEC 61000-4-7 sub-group concept and their effects on...
Continuous increase of numbers of various modern power electronic (PE) devices requires careful investigation of their impact on both operation of distribution networks and other connected equipment. This paper discusses typical harmonic models and modelling techniques, using as examples electric vehicle battery charger (EVBC) and compact fluorescent lamp (CFL). Different models and modelling techniques...
This paper presents results of comprehensive tests of 18 different on-board electric vehicle battery chargers (EVBCs), representing the majority of currently available passenger-car-type EVs in the European market. The presented analysis compares the harmonic characteristics of EVBCs, concentrating on the impact of variations in supply voltage magnitude on emission of low frequency harmonics, as well...
This paper presents the results of testing and analysis investigating impact of operating conditions on harmonic and interharmonic emission of PV inverters. Tests include typical supply voltage distortion and source impedances. Measurement procedures and metrics recommended by standards for evaluating harmonic and interharmonic distortion are discussed. Finally, it is investigated how the Maximum...
Monitoring of voltages and currents at system buses gives the network operators information about the performance of their network, both for the system as a whole and for individual locations and customers. There is also demand from the customers and the regulatory agencies to provide information on the actual power-quality (PQ) level. Developments in enabling technology have made it possible to monitor...
Conventional inductive voltage transformers (VT) are widely used in MV, HV and EHV networks to measure harmonic voltages. Accuracy of VTs at frequencies other than nominal frequency (50Hz/60Hz) are not defined by standards, but may significant influence the overall accuracy of harmonic measurements. Thus a reliable compliance verification of compatibility levels, planning levels or emission limits...
In 2007 the German-Austrian-Swiss-Czech working group “D-A-CH-CZ EMC” published the 2nd edition of the “Technical Rules for the Assessment of Network Disturbances”. They are used in the 4 countries to assess the emission limits of large consuming and generating installations (in Germany consuming installations only). The rules define assessment methods and emission limits for LV and MV distribution...
Power quality in distribution grids is determined by consumer topology, generation topology, network topology and other non-electrical, environmental influences (i.e. weather). New developments in all mentioned characteristics, e.g. micro generation or e-mobility lead to significant changes in the grids and the equipment connected thereto. This paper discusses possible impacts of new technologies...
Voltage quality plays an important role in modern distribution networks. One voltage quality parameter is harmonic distortion. Voltage harmonics in MV-networks are measured in most cases by using installed inductive voltage transformers (IVT). The accuracy of these transformers for frequencies above nominal frequency (50Hz or 60Hz) is usually not known. The paper presents a systematic analysis of...
Nowadays power quality, especially voltage quality becomes more and more important for utilities, manufacturers and customers as well as for the regulatory authorities. Therefore a growing number of voltage quality monitoring campaigns with continuously increasing measurement times, considerably longer than one week, are observed. The assessment of voltage quality according to common standards (e...
In public distribution networks the distribution network operator (DNO) is responsible for the voltage quality at all points of supply. In Europe the DNO have to guarantee specified values for voltage quality parameters according to EN 50160. Due to the wide use of electronics in electrical equipment and installations as well as the increase of dispersed generation, the disturbances on the supply...
The paper describes a new method for modeling power quality parameters (e.g. harmonics) particularly in public low voltage networks. The technique is based on the correlation between the trend of power quality parameters in a low voltage network and the characteristics of the consumer structure connected to the MV/LV-substation. A mixture of single Gaussian distributions is fitted to the data of each...
Determination of power quality becomes more and more important in the future. Low voltage networks are usually large and very complex. Therefore the calculation of power quality parameters by modeling as equivalent network is hardly possible in practice. That's why new methods for efficient and exact estimation of power quality parameters in low voltage networks are necessary. The presented method...
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