Determination of harmonic current contributions at points of common coupling of the electrical system based on field measurements

In this paper, a method is proposed to determine the harmonic current contributions of the loads supplied from a point of common coupling and the utility, based on identifying harmonic current sources in the system analytically, by calculating utility and load impedances from the field measurements of current and voltage. In the proposed method, the harmonic current contributions of loads and the utility are determined through the harmonic Norton equivalent circuit model of the system constructed on the basis of the measurements of current and voltage harmonics. This method can be applied to any circuit scheme in the system and it is also able to determine the harmonics inserted to the system from the utility side. The method is verified by both computer simulations and application on field data obtained by the Power Quality Analyzers (PQ⁺) developed through the National Power Quality Project of Turkey. Results show that the proposed method can be used as good prediction tool to determine harmonic current contributions at the point of common coupling.