This article presents the analysis of the influence of household appliances on the quality of the energy consumed by the end-user. The results of the research, then, concern the final consumer (the lowest level of the power grid). The research was conducted on 120 combinations of electrical appliances connected into a grid. Each combination consisted of three devices working simultaneously in a micro-grid. The obtained and statistically analyzed data proved that there are several types of appliances that have a great influence on the power quality (PQ) parameters changes. The results of the conducted experiments indicate the devices which influenced significantly the total harmonic distortion of voltage (THDV), the voltage frequency (FREQ) and the voltage fluctuation (V). Specific features of particular devices were examined in terms of their significance for the power quality deviation. This showed the most important features which should be considered while working out the prediction model. The future of smart grids resides in data analysis, predictive models and real-time optimization. One of the key characteristics is the reducing energy consumption generated by renewable energy sources. This phenomenon, namely looking for problems connected with sustainable power quality and their appropriate solution, is described in this article. We performed an extended analysis of the smart home appliances influence of individual quantities on a real model. Furthermore, we explored devices with a high impact on chosen power quality indicators. In the end, we discuss their specific behavior and relevance to the above-described phenomenon to improve the predictive model utility.

Narrowband power-line communication seems to be a suitable communication technology designed for off-grid renewable energy solutions. Existing electrical installations can be designed both for the transmission of electricity and for the communication of electrical equipment operating inside such an installation. This study presents an implementation of the above-mentioned off-grid communication system and examines the basic problems related to its exploitation. The authors of this article focused their attention primarily on examining the disturbance of the communication channel caused by the use of typical electrical devices, such as: a light bulb, a kettle, etc. used in a household. The aim of the research was also to find the impact of switching on individual devices and their combinations on the disturbances during data transmission. Measurements of incorrectly transmitted data packets were carried out and then the test results were referred to the error measures. Moreover, the influence of the carrier frequencies on the signal attenuation and the method of eliminating the existing interferences were also discussed.

Appropriate method to analyse aerodynamic flow in wind turbine is Computational fluid dynamics (CFD). This is the reason why we choose this method to analyse the effect of turbine enclosure on static torque characteristics of vertical axis wind turbine (VAWT) with straight blade. Analyses are realized by use of Ansys CFX software. At first, we carried out simulations of turbine without an enclosure. Next step was to find out a dimensions of the enclosure that increase the torque of the turbine. From the analysis results we selected the enclosure that had overall highest increase of average torque over the turbine without any enclosure at wind speed 5 and 10 m/s. Analysis at two wind speeds are performed for a reason to find out how the effect of the enclosure on turbine torque changes.

Nowadays Off-Grid systems driven by intelligent data analysis, predictive models and real-time optimizations are frequently entitled as Smart Grids. They represent a future step in a sustainable energy supply for applications at various scales, from small household configurations to the systems operating on a scale of larger areas, especially parts of a town or village. One of the key characteristics of such systems is the lower short-circuit power caused by a lower and mostly stochastic nature of their power source, which is represented by a renewable energy source. This phenomenon directly implies the difficulties of sustainable power quality (PQ). Our paper presents an analysis on the lowest possible level, where the impact of household appliances is examined towards a specific kind of response due to PQ parameter variation. The analysis was performed on 120 combinations of appliances. Each combination consisted of three appliances running simultaneously in the microgrid. The measured data were subjected to a statistical analysis. This analysis finds there are several kinds of appliances we need to focus on, in order to express the PQ parameter change of a given parameter. The results show that the microwave, AC heating and drill appliances had a high impact on the total harmonic distortion of voltage (THDV) disturbance. The microwave, AC heating and mower had the highest impact on the total harmonic frequency (FREQ) and the power factor (PF). For the sake of completeness, specific features of the given appliances were examined as for their relevance to the PQ disturbance, which revealed the most relevant features to be taken into account during the development of a predictive model.