Ensuring quality of power supply is a main target of the power utility companies worldwide. Harmonic distortion is one of the power quality problems that can result either from upstream (utilities side) through background harmonic, downstream (customer’s side) through non-linear loads or renewable energy generators. The detection of harmonic sources at the Point of Common Coupling (PCC) is a major concern for both utilities and customers. Various methods have been proposed since the 1990’s to be used for harmonic source detection. These methods have been classified into three categories based on the direction of active power flow, reactive power and voltage -current ratio. In this paper a systematic literature review is done on the state-of-the-art of current research on the harmonic source detection methods, in order to select the method that gives better practical and commercial results to be used when multiple customers are connected at the PCC. This systematic literature review recognized that most studies concentrated only on harmonic source detection between a customer and utility, but the practical power system has multiple customers connected to the PCC with different load conditions. Therefore, the results obtained from this literature review will be useful for researchers and engineers working in the modern grids, who aim to develop a practical and commercial methods to quantify the harmonic contribution for different customers and utility.

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.

Smart grids are reliable and easy to operate though it increases the challenges of harmonic distortion due to many electronic devices. Traditionally, harmonic distortion is neglected when efficiency in distribution networks is determined. They are usually calculated using fundamental frequency only. The efficiency of equipment and the overall efficiency of the network is negatively affected by the harmonic distortion. Thus, this paper seeks to develop a methodology and new formulae for determining individual and overall efficiencies when harmonic distortion is present in a distribution network. The methodology and new formulae are developed using the directional active power flow. A radial distribution network with two harmonic sources (non-linear load and Solar Photovoltaic(PV)) and a capacitor bank is used for analysis. The method and case-specific formulae are applied in this case study and results are generated. A harmonic filter is designed and implemented. It is indicated that the overall efficiency of the distribution network as well as the individual efficiency of the network is affected by the presence of harmonic distortion. Once the harmonic filter is implemented the overall efficiency of the network is improved significantly. The methodology and formulae have shown to be effective since it gives a better understanding of efficiency when distortion exists and its application is recommended for industrial use.