A Proposed Harmonic Monitoring System for Large Power Users Considering Harmonic Limits

Most power utilities within Southern Africa are faced with the challenges of harmonic distortion due to the high penetration of renewable energy sources (RES) and the use of electronic devices. There is an excessive total harmonic distortion (THD) measured at the point of common coupling (PCC). In this paper, a proposed harmonic monitoring system for large power users (LPUs) is developed. This proposed system considers harmonic limits of the individual and THD of the customers allowed injecting into the network, which should be part of the contractual electricity supply agreement (ESA). Hence, it will enable the monitoring of harmonic distortion to be smooth by determining whether the customer has passed or failed compliance for individual harmonic order and the THD of the voltage. The measurements of harmonic distortion are done using the Unipower power quality (PQ) analyzers that are connected at different points within the industrial network. Measurements of harmonic distortion of an industrial site are compared to the simulation results performed by DIgSILENT software to validate the proposed harmonic monitoring system. Based on the validation results, it is recommended that the ESA between the power utilities and the customers should consist of the harmonic limits.