Smart cities are an innovative concept for managing metropolitan areas to increase their residents’ sustainability and quality of life. This article examines the management and evolution of energy generation, various storage systems and the applications they serve, and infrastructure technology’s current condition and future prospects. Additionally, the study also examines energy-related construction and transportation systems and technologies. The Smart Cities Energy Prediction Task Force predicts electrical usage using STLF, SVM, and e-learning machines. To keep a system working well throughout the year, fossil fuels must be utilised as a backup energy source. Technologies can only benefit if integrated into the city’s infrastructure. By 2050, it is anticipated that the global population will surpass 10 billion, with most people settling in metropolitan regions. Between 2020 and 2027, the global market for smart energy is anticipated to expand by 27.1% annually, from USD 122.2 billion in 2020 to USD 652 billion in 2026. In 2020, Europe will account for 31.8 per cent of total smart energy product sales. China’s GDP is projected to grow by 33.0 per cent annually, reaching USD 176.1 billion by the conclusion of the analysis period. Consequently, smart cities are expanding and blooming worldwide, yet there are no permanent standards.

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.