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• Numerical methods used for the estimation of the RMS. • Simpson's 1/3 rule and Simpson's 3/8 rule modified for the purpose of general application. • Modified Simpson's rules do not necessitate more complex mathematical calculations than those used in the existing methods. • Modifications provide better measurement results for some a lower ratio of the frequency of sampling and the frequency of the signal. • Modified methods do not require the manufacturers of commercial measurement equipment to additionally invest in it. This paper demonstrates that direct changes in the algorithm for the estimation of the root mean square value of a voltage signal of an arbitrary waveform can lead to improved performances and lower measurement uncertainty of commercially available instruments without requiring any upgrade of their existing hardware. The research conducted and presented here is an original contribution to the development of estimation techniques and mathematical models for measurement oriented purposes regardless of the number of samples in the given period relying on mathematical calculation of the equal complexity as in the methods already in use. The theoretical approach examines the problem of numerical integration focusing on modified Simpson's 1/3 rule and modified Simpson's 3/8 rule used for the purpose of the estimation of the root mean square value when a small number of samples per period is available. It highlights the limitations of Simpson's 1/3 rule and Simpson's 3/8 rule, and shows that the newly proposed algorithm is optimal with respect to measurement accuracy and precision even in cases when the ratio of the sampling frequency and the signal's fundamental frequency is low. All theoretical results have been validated experimentally. [ABSTRACT FROM AUTHOR]

• Power line accessories are traditionally considered passive components. • Harvesting surge energy to signal potential failures of critical accessories. • Powering sensors and IoT components to communicate equipment status. • Proving the concept and feasibility of power lines digitalization in a cost effective way. This paper presents a design of a batteryless Internet of Things (IoT) module for upgrading power lines accessories such as surge arresters and insulators with responsive capabilities. The module is able to power itself from the failure current and to signal the nature and consequences of the failed accessory to a remote dispatch. It comprises an energizing circuit, a signal shaping circuitry, a custom-developed continuity indicator, and a low power communication microprocessor with programmable settings. The paper provides an elaboration of the constraints under which such a device must operate, simulation results on its feasibility, analytical calculation of optimal placement of certain components in 3D and measurement results to support the underlying theory of its operation. The research is an original contribution to the field of customized low energy computing and cyber-physical systems incorporating optimized microprocessor solutions applied to the IoT concept. [ABSTRACT FROM AUTHOR]

Calibration of measuring transducers for precision measurement is done by measuring voltage drop at the resistor standard, produced by output dc current proportional to the input measured value. Resistance fluctuations due to the temperature coefficient of the resistor standard are minor, thanks to the stable temperature conditions in laboratory environment. This fact brings the need to calculate the effect of resistor self-heating on its resistance. This thermal effect, produced by the flow of current through the resistor, is often disregarded. For the precise measurements this can be a significant source of error and must be quantified. This paper describes mathematical model of measurement error, resistor self-heating coefficient is defined, as it's not usually given in product datasheets. The effect on measurement results is given in detail. Composite resistor standard prototype is described, made from off-the-shelf mass produced components, calculated and hand selected to cancel the self-heating coefficient effects. The prototype is compared to the existing commercially available high performance resistor standard. [ABSTRACT FROM AUTHOR]