This paper presents the metrological evaluation of a proposed virtual power quality (PQ) disturbance generator. The calibration and measurement uncertainty estimation procedures for the RMS voltage and frequency of the generator are explained in detail and the obtained results are presented and discussed. The results show that the measurement uncertainty of the PQ disturbance generator for all reference points is satisfactory, making it suitable for generation of PQ signals for research purposes, especially in the development, testing and improvement of PQ event classifiers.

This study applies a Monte Carlo method (MCM) to estimate the uncertainty related to the determination of the annual flow duration curve determined at a river weir, considering the dynamic behaviour of processes and the intrinsic uncertainty contributions to the raw data. The computation of the curve uses a time series of average daily flow data collected at a hydrometric station at an upstream river section. This curve was used for a hydropower plant feasibility study. Results show how model uncertainty can be estimated from the measurement uncertainty of raw data and mathematical formulation applied.

The guard banding approach is tested to meet the NLGI grade of lubricating grease specifications. Different guard band formulae were tried to compare the customer and manufacturer risks during production release testing. The results show that the called risk management approach for guard banding offers the best results for the trade-off between the producer risk without compromising the targeted level of consumer risk for the particular case of symmetrical but high-preferred specifications limits.

In this paper, the possibilities and important factors that can influence the prediction of the life time (life cycle) of a measuring instrument used in the field of legal metrology, which is found in everyday work and in different working conditions, are considered. Based on the measurement history and a large number of measurement results data, significant factors (history of measurements, different provider of services, measurement uncertainty and environmental conditions) that can influence the judgment of the life cycle of the measuring instrument were analysed. The presented results indicate the further research for development of a more efficient, faster and better system meant for consumer protection from inaccurate measurements.

The spreading of photovoltaic (PV) systems as solar panels can be seen around the entire world. The product authorisation and validation process in the case of standard size roof solar panels is a wellestablished practice, however there are an endless variety of non-standard size PV panels. The validation of such units is not always a standard and straightforward procedure, as it is not always clear whether a PV panel is an electrical device or a building material. This paper discusses a possible methodology of the validation of non-standard size PV elements according to the IEC 61215 standard [1].