Development of tools for accurate study of supraharmonic emissions in smart grids

As the worldwide concern for the climate change and its effects are growing, the governments are forced to make strong decisions in favour of the implementation of the smart electrical grids. However, the success of these actions strongly depends on meeting the certain requirements of the electricity system raised by the quality of the energy supplied and the means to assess it. The smart electrical networks have to tackle the challenges raised by the increasing uptake of the renewable energy sources, such as the photovoltaic (PV), wind, etc. and the equipment, such as photovoltaic inverters (PVI), electric vehicle chargers (EVC), etc. This introduces a complex dynamic operating environment for the distribution system. The distortions coming from the new generation and load equipment are generally larger and less regular than those due to the traditional generation and load equipment, making the power and energy measurements difficult to perform. In this context, the thesis aims to quantify and reproduce the supraharmonic emissions in the frequency range of 2 kHz to 150 kHz. Therefore, the existing literature on the supraharmonic emissions in the frequency range of 2 kHz to 150 kHz is studied. The 4-channel measurement system is designed and implemented for the measurement of the fundamental and supraharmonic components of the voltage and current waveforms in the frequency range of 2 kHz to 150 kHz in the electrical network. The measurements are carried out in the EDF’s Concept Grid platform. The individual equipment characterization and electrical network tests are carried out here. The waveforms acquired during the measurement campaigns are processed mathematically using the fast Fourier transform (FFT) algorithm and statistically using the analysis of variance (ANOVA) algorithm. The mathematical and statistical processing of the acquired waveforms helps to determine the individual effects and interactions of the different parameters in the generation of the supraharmonic emissions in the electrical network. The various parameters, such as the primary and secondary emissions, effects of the cable length, effects of the sudden addition and removal of the load equipment are also studied. The thesis describes the design of the complex waveform platform, which can be used for the laboratory testing and the characterization of the power quality analyzers (PQA) in the frequency range of 2 kHz to 150 kHz. In the electrical networks, the waveform platform can be used to measure the supraharmonic emissions in the frequency range of 2 kHz to 150 kHz. The software architecture of the waveform platform is described here. In addition, the paper explains the hardware design of the waveform platform. It also includes the laboratory and electrical network applications of the waveform platform. The laboratory setup for the characterization of the PQA and the measurement schema for the electrical network waveforms are also depicted here. The uncertainty budget for the waveform platform is calculated considering the various factors, such as the cable length, noise, etc. are discussed in the thesis. Finally, the PQA is characterized in the frequency range of 2 to 150 kHz with respect to the waveform platform for varying emission amplitudes.

power quality, renewable energy sources, smart grids, supraharmonic emissions, waveform platform

PhD thesis: https://tel.archives-ouvertes.fr/tel-02498270