## 1 Introduction  
Over the course of time and thanks to technological development, renewable energies have experienced great growth in recent years, and everything indicates that this increase will continue in the future [1], reducing dependence on fossil fuels and allowing a closer approach to the environmental objectives set by different countries and organisations [2]. With more than 700 GW of capacity globally, solar PV was the most installed renewable energy source in recent years. It is now considered the fastest growing power generation source, representing 48% of the world's clean energy capacity installed and connected to the grid in 2020; and the forecast is that in the next few years, the world's solar generation would reach the terawatt production capacity level [3, 4]. One of the reasons for this increase in PV power capacity has been the reduction in PV prices over the last few years, a reduction which is still continuing [5]. The cost of generating electricity from distributed solar PV systems is already below retail electricity prices in most countries. The International Energy Agency (IEA) forecasts that these costs will decline by a further 15 to 35% by 2024, making the technology even more attractive and stimulating its adoption worldwide [3,6]. Improvements in module performance, as well as the simplicity and reliability of such installations, have also contributed to their widespread use. In addition, the increasing penetration of this technology will reduce the dependence on imported energy resources in many countries [7]. A significant percentage of the installed solar energy corresponds to distributed PV systems in homes, commercial buildings and industry [8,9]. The capacity of this type of installation has almost tripled since 2014, transforming the way electricity is generated and consumed; and it is expected that the distributed PV accounts for almost half of the growth in the overall solar PV market through 2024 [6]. These figures could even increase in the future with the application of innovative solar photovoltaic roof panels to better integrate generation into the construction of buildings [10]. However, LV distribution electricity systems were designed as passive networks in a radial style, and were not meant to accommodate distributed generation, so the integration of renewable energy systems (RESs) in electricity networks may cause some issues and impacts on the power quality, protection coordination and operation of distribution feeders that need to be carefully analysed [11,12]. PV generation is highly variable, which is one of the main drawback of the large-scale application of PV in distribution networks [13,14]. The irregular nature of the solar radiation, often caused by the rapid pass of different types of clouds or by the presence of shadows [15], means that the output of this type of installation presents intermittency or random fluctuations [16]. The transient atmospheric changes that affect the variability of renewable production has a stochastic character in general with different conditions of duration, frequency, magnitude and shape [17]. The duration of irradiance transitions may vary from a few seconds up to several minutes, and the number of transitions in a day can be as many as 500, the highest transition rates taking place around noon [18]. These irradiance fluctuations can lead to situations where the inverters are not able to follow the global maximum power point (MPP) causing extra losses, and partial shading of PV generators also causes mismatch losses [15,18]. Moreover, this fluctuated dynamic of electricity production, which mainly affects small PV installations due to their not exhibiting the smoothing effect present in larger ones [19], may have its consequences in customers, residential and industrials, and even in the own network.