Here you can download the file "Proceedings of the Third International Colloquium on Intelligent Grid Metrology SMAGRIMET 2020"
Metrology is at the heart of the present development of intelligent grids: there is no such thing like an intelligent grid without measurements. This presentation will highlight the significant contributions metrology presently is making to the development of intelligent grids, with an outlook to the challenges that still lie ahead. This will among others cover the calibration of PMUs and digital instrumentation for grid monitoring and control, ensuring correct metering under highly polluted grid conditions, measurement of power quality up to the supraharmonics range, testing of grid components at increasingly high grid voltage levels, and reliable efficiency measurements of power transformers and reactors. The challenges are unprecedented, with needs for traceability of digital instrumentation, for on-site measurement in grids and at test sites, and for metrology support to data analytics aiming to turn the vast amounts of grid measurement data into actionable information for grid operators.
Currently, frequency measurement is one of the most popular tasks in power engineering. The voltage and current of real power networks are different from sinusoidal ones: there are harmonics, supraharmonics, noise and flicker. For this reason, the application of measurement methods designed to measure the frequency of a sinusoidal voltage results in larger measurement errors. This article discusses two most popular frequency measurement methods applied in power engineering: zero crossing technique and a method based on the amplitude spectrum analysis. The article provides a description of each method, indicates the main advantages and disadvantages, considers the features for the practical implementation. Analytical relations are obtained which allows to estimate the methodological error of all the methods under consideration. In the article main modification directions for the considered methods are shown, aimed mainly at simplifying the implementation and reducing the methodological error. The influence of the parameters of the input signals, namely the sample rate and the measurement time, on the measurement error of the frequency is considered. A comparative analysis of the methodological error of the considered methods for the cases of sinusoidal signal, polyharmonic signal and combined signals (sinusoidal signal and sinusoidal flicker) was made by simulation modeling in Matlab and Simulink software. The influence of supraharmonics on the measurement error of each of the considered methods is considered. The reliability of the obtained analytical relations is confirmed by comparison of the results of analytical and simulation modeling at check points.
In the framework of the EMPIR project MyRailS, METAS developed a primary standard for electrical power using commercial off-the-shelf components. Custom software controls the sampling system and determines amplitude and phase of the different frequency components of voltage and current. The system operates from DC up to 9 kHz, even with distorted signals. The power uncertainty is 15 μW/VA at power frequencies and increases to 1.8mW/VA at 9 kHz. The voltage and current channels can also be used independently to calibrate power quality instruments. Thanks to a time-stamping system, the measurement is synchronised to UTC.
The timebase inaccuracy of an Analog-To-Digital Converter (ADC) is an important systemic error to consider when it comes to fast and precise mains frequency measurement. In this paper, a new calibration method to determine the timebase offset of an ADC in real time to correct the mains frequency measurement is proposed and evaluated in tests. The methods uncertainty with regard to different calibration signal frequencies is assessed.
An algorithm to locate the rising edge zero crossings of the mains fundamental while working in the frequency domain is presented and evaluated. Working in the frequency domain allows easy compensation of the effects of the coupling between the measurement equipment and the power line. Using a modified Discrete Fourier Transform with a raised cosine filter kernel greatly increases frequency selectivity of the generated phasors, especially when measuring noncyclic signals. Zero crossings are located from the gradient of the phase of the mains fundamental and collected as points in time as well as sample indices.
Resilient, reliable and efficient electrical grid operation is critical to society. The electrical power and energy industry is changing rapidly to meet the demands of the society and address decarbonization needs. New technologies offer significant opportunities for realizing a resilient and sustainable energy future. Identifying the best strategies to ensure reliable, resilient, and cost-effective delivery of electrical power energy is needed to set a path to decarbonization to address climate change. Those strategies include integration of renewable energy resources and electrical storage and together with electrification of transportation and innovative approaches to building climate control are critical ingredients of any energy future. It is critical to ensure that inverter-based resources like solar PV and battery energy storage systems have the capability to provide essential reliability services to the electric power system. The grid also continues to face evolving challenges, such as cyber and physical attacks, major weather events (e.g., catastrophic wildfires, hurricanes, significant rain/snow incidents) and aging infrastructure. We have the opportunity to make it better than it was before by taking more aggressive actions to adapt, including grid infrastructure hardening and improved grid and equipment monitoring. What we need now is a renewed understanding of the value of not just electricity, but the grid that enables it, and recognize the contributions of renewable energy resources, energy storage, and electrification in achieving environmental, resilience, reliability, and safety targets. We are at a crossroads in making business and technical decisions that will allow us to optimally and cost-effectively manage the grid. This presentation will discuss success factors for sustainable electrical energy delivery in the context of industry trends and transformation drivers and opportunities for grid modernization with technologies for the changing nature of electricity delivery and decarbonization.