Harmonic sources estimation in distribution systems

Management and control of modern power networks need new effective distributed monitoring systems providing accurate and reliable information on the actual operating conditions of the grids. These systems are required to produce information composed of different types of data, reported with different reporting rates, and characterized by different uncertainties. Therefore the evaluation of the quantities of interest and of their accuracy is a crucial point to use such data in an effective way. This is particularly challenging in the scenario of modern distribution grids, where operating conditions are increasingly distant from traditional ones and power quality issues, such as harmonic pollution, are critical to detect. In this context, this chapter presents state of the art, challenges, and novel approaches for harmonic sources estimation in distribution systems. In particular, a new methodology based on compressive sensing is presented in detail. This procedure is designed to estimate the main sources of harmonics in distribution networks, relying on a nonredundant distributed and synchronized measurement system. Different sources of uncertainties are considered along with the requirements and challenges of estimation steps. Benefits of the use of harmonic phasor measurements are presented and discussed through some significant estimation examples.