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Resonances in electrical distribution systems can result in amplification of harmonics, which is undesirable in electrical networks. To avoid intrusive measurement techniques, in the majority of the cases network modeling is used to validate if there is an issue with resonance. In this paper a new, innovative but simple, concept is presented which uses relatively basic measurements to segregate the power related to specific harmonics into active and non-active harmonic power. These results are subsequently used in order to find if there is resonance in the electrical network. In this paper the concepts are explained on a theoretical basis and are test cased by numerical modeling. The initial results look promising but additional research is needed to validate the method.

With the onset of renewable power sources onto the network, such as Photovoltaic power plants contributing to Total Harmonic Distortion (THD) in voltage, a methodology to quantify their contribution to the THD in voltage at the point of common coupling is needed. This paper give an overview of existing theory on the quantification of harmonic emission and in particular the method proposed by the CIGRE/CIREDC4.109 working group. It is concluded that the application of this method by single-point measurements can be improved upon by using synchronized multiple-point measurements. Discrimination to identity the harmonic currents regarded as emission is attempted in the assessment of harmonic emission at a PV plant feeding into a 22 kV distribution network

Harmonic emission assessment in high-voltage networks with a number of renewable power plants (RPP) interconnected is challenging. A sound scientific methodology readily accessible to engineers is needed to validate the compliance to grid code requirement set by the distribution system operator. Harmonic phasors recorded coherently all over the network can cause an impractical volume of data. This study investigates the opportunity to improve existing methodologies by application of the prevailing angle in a harmonic phasor as an approach to significant reduction of data and then demonstrate the evaluation of grid compliance in a network with a number of RPP interconnected. It is shown that the unrelated dynamic nature of the different non-linear energy sources does compromise the practical application of the prevailing harmonic phase angle. It is then concluded that the dynamic nature of RPP necessitates continuous monitoring of grid code requirements on harmonic emission.

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