No abstract

Power quality assessment is a complex measurement task, requiring the usage of a system with suitable metrological properties. This complex measurement task in the real power grid is performed with the use of power quality analysers that measure and record the parameters determining the power quality. The paper presents selected research results for a class A power quality analyser in the specially prepared measurement system containing measuring instruments calibrated by the Main Office of Measures. The measurement results were completed with a presentation of the uncertainty budget. The influence of the phenomenon of spectrum leakage on metrological properties of the tested power quality analyser was considered in the paper. To assess this influence, the simulation studies with the use of MATLAB and the experimental studies were carried out for selected test signals. The Metrological interpretation of the research results is presented in the paper.

Electroluminescent diodes have become increasingly popular on outdoor billboards for the last few years, all over the world. Digital billboards with electroluminescent diodes are large, have high luminance and display dynamically changing images. Billboards located near streets are a potential threat to traffic safety. The paper presents requirements for such billboards, the results and analysis of measurements of selected billboards located in Poznań, Poland, as well as conclusions and recommendations for large size billboards with light emitting diodes located in the vicinity of roads and intersections.

The pedestrian is the least protected road user. A large number of accidents involving pedestrians occur at pedestrian crossings. Bad lighting or a complete lack of it is one of the causes of accidents in these places. Currently, there are no uniform requirements in Europe for the lighting of pedestrian crossings. Each country is trying to create its system of requirements and assessment of lighting of pedestrian crossings. Measurement procedures and required lighting parameter values often vary significantly across countries. This paper discusses the results of measurements carried out at selected pedestrian crossings using two different measurement grids. The lighting quality at the tested crossings has been assessed based on the lighting requirements in force in two EU countries. In addition, we present the results for the illuminance contrast of a measurement board, representing the silhouette of a pedestrian on a crossing, with the background. Based on the determined contrast, we attempted to verify the lighting conditions using an evaluation system described in the literature, which employs fuzzy logic algorithms.