Faults detection and analysis in PV system are considered critical for ensuring safety and increasing output power of PV arrays. PV faults do not only reduce output power and efficiency but also lessen the working life time of a system. Most common and chronic PV faults are line to line, line to ground, shadowing fault, and arc fault while less common and acute faults are hotspot, degradation, bypass diode, and connection faults. Event of PV fault detection failures, such as most recent in Mount Holly, USA in 2011 evinced the improvement in current fault detection and mitigation techniques to shrink such failures. There are various limitations in the existing fault detection techniques, as identified in this paper, which may cause misdetection of the faults. This paper is focused on mathematical formulation of various PV faults and lead to the latter's critical analysis in terms of efficiency, accuracy, complexity, and reliability. The presented work also helps to identify nature and causes of occurrence of a PV fault. This research work serves as a special set of references and recommendations for researchers and PV manufacturing industry to improve fault detection prospects in solar PV systems.

Fault analysis in photovoltaic (PV) arrays is considered important for improving the safety and efficiency of a PV system. Faults do not only reduce efficiency but are also detrimental to the life span of a system. Output can be greatly affected by PV technology, configuration, and other operating conditions. Thus, it is important to consider the impact of different PV configurations and materials for thorough analysis of faults. This paper presents a detailed investigation of faults including non-uniform shading, open circuit and short circuit in different PV interconnections including Series-Parallel (SP), Honey-Comb (HC) and Total-cross-Tied (TCT). A special case of multiple faults in PV array under non-uniform irradiance is also investigated to analyze their combined impact on considered different PV interconnections. In order to be more comprehensive, we have considered monocrystalline and thin-film PV to analyze faults and their impact on power grids. Simulations are conducted in MATLAB/Simulink, and the obtained results in terms of power(P)-voltage(V) curve are compared and discussed. It is found that utilization of thin-film PV technology with appropriated PV interconnections can minimize the impact of faults on a power grid with improved performance of the system.Energies 2020, 13, 156 2 of 23 ground faults which led towards a large fire accident [6]. Another similar accident happened due to undetected faults in a 1 MW PV system of Mount Halley, North Carolina in 2011 [7]. Thus, timely diagnosis of faults in PV systems is very important for the prevention of such large fire accidents [8]. The modeling of a PV system under electrical faults [9] has been studied in the literature [10]. A review of faults in PV systems is presented in [11]. Power generation is also dependent upon the type of PV material [12]. The impact of shading on different PV technologies [13] has been largely investigated in the past [14][15][16][17][18]. The performance of crystalline PV material can be affected greatly by environmental conditions [14]. P-V curve analysis for studying the impact of shading on polycrystalline and thin-film PV modules was performed in [15]. Thin-film PV performed better as compared to polycrystalline PV under severe shading in terms of power output. The experimental analysis of PV material in Anatolia also proved that thin-film technology has less impact on shading and high temperature as compared to crystalline PV material [16]. Only shading and temperature conditions are analyzed for thin-film PV technology [17]. Further research is needed to investigate the impact of short circuit and open circuit faults on thin-film PV technology.Different methods of maximum power point tracking (MPPT) [18] have been investigated but improvements in the algorithm cannot compensate for significant power losses that occurr through fault occurrence in PV arrays. A reconfiguration technique was adopted in [19] to increase power generation but this technique requires a complex switching matrix with many sensors and prope...

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Cross-border power trading through grid interconnection has gained significant attention in South Asia to support energy deficit states of the South Asian Association for Regional Cooperation (SAARC) region. Nonetheless, cross border grid interconnection requires technical standardization and grid code synchronization to ensure technically feasible, reliable, safe and economical power exchange among the SAARC states. Importantly, grid code harmonization necessitates the uniformity of technical data and codes among the member states. In this paper, we investigate the relevant factors such as regional barriers, trade potential, a gap in the grid codes, standardization of technical data, energy pricing, load profile, the load factor of different states, and regulatory framework of different states. All these factors are found to be helpful in formulating a set of recommendations for seamless power grid interconnections and power trading. We have developed a power pool model for the SAARC region with an objective to effectively realize the objectives of cross-border power trade in the region. The presented model takes account of transparency in market-clearing price, bidding of data, season-wise load profile, market volume, best case practices, institutional setup and rigorous case studies to ensure seamless grid interconnection and reliable power trading within the region.INDEX TERMS Cross-border power trade, standardization of technical data, grid code harmonization, power pool model.

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