A New Method for Separating Utility and Customer Harmonic Contribution at The Point of Common Coupling

Noraliza Hamzah, Azah Mohamad, Aini Hussain


Harmonic disturbances can have significant technical and economic impacts for manydifferent types of facilities equipment and customers? loads. This paper proposes a new method tomeasure harmonic contributions by utility and customer at the point of common coupling in anindustrial distribution system. The new method is based on the sign of the reactive power gradientmeasured at the point of common coupling (PCC). Simulations were carried out by considering asaturated transformer as harmonic producer at the utility side and an adjustable speed drive asharmonic producer at the customer side. In the proposed method, the reactive power at the point ofcommon coupling which is between utility and customer sides are measured and plotted againsttime. A least square method is used to perform the line fitting for the reactive power against time ofthe harmonic distortion to detect harmonic source. A positive gradient indicates that utility is themain contributor of harmonic distortion at PCC and on the other hand, a negative gradient indicatesthat customer is the main contributor of harmonic distortion at PCC. Results from simulations haveverified that the new method is technically sound as it only requires voltage and current measurementsat the PCC.

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