Study of Energy Compensation Techniques in Photovoltaic Solar Systems with the Use of Supercapacitors in Low-Voltage Networks

Abstract

The power generated by photovoltaic solar systems is exposed to high variability of irradiance mainly due to weather conditions, which cause instability in the electrical networks connected to these systems. This study shows the typical behavior of solar irradiance in an Andean city, which presents considerable variations that can reach up to 63% of the nominal power of the photovoltaic system, at time intervals in the order of seconds. The study covers the application of 3 techniques to reduce power fluctuations at the point of common coupling (PCC), with the incorporation of energy storage systems, under the same irradiance conditions. Supercapacitors were used as the storage system, which were selected for their high efficiency and useful life. A state of charge control is also applied by means of a hysteresis band. The three algorithms studied show similar behaviors; however, the ramp control technique has the best performance. The storage system was dimensioned based on the photovoltaic system’s nominal power and the desired rate of change in the PCC, whose capacity can be estimated from Pnom/12 [kWh] and a maximum power that can reach up to 0.63 Pnom. The study determines that based on the storage capacity and the irradiance characteristics under study, the storage system could use at least 5.76 daily charge/discharge cycles. In the study, it is possible to reduce the rate of change of the photovoltaic energy injected into the PCC about 6.66 times with the use of the proposed energy storage system.

Quaternary Cu2FeSnS4/PVP/rGO Composite for Supercapacitor Applications

“…In such a scenario, the so-called unconventional energies should be used to meet energy requirements. 1 , 2 The one of the drawback is that there is no sustainable storage source to store such energies. Supercapacitors and batteries are a potential source of energies for practical use, while principle energy sources can be exhausted.…”

Converting a Water Pressurized Network in a Small Town into a Solar Power Water System

“…Investigators and practitioners have developed projects optimizing PV systems [19,20] and studied the influence of meteorological variables [21][22][23]. Researchers have presented procedures in photovoltaic generation forecasting to mitigate uncertainty [24][25][26], with the aim to incorporate the spatial correlation of PV modules [27] or reducing fuel consumption in a hybrid system (with a diesel generator and photovoltaic resources) [28].…”

Ramp-Rate Control of DRES employing Supercapacitors in Distribution Systems

“…In many studies, e.g. [12], the SoC is related with the stored charge, i.e. a definition more directly related to the equivalent concept of BESS, [14].…”

“…When involving BESS, slower dynamics are involved, hence, in [9] it is recommended that fast-acting ESS are used for the power smoothing. This is further supported in [12]: the use of the SCs is recommended for the RRL in LV networks, since the SCs can mitigate ramp-ups and ramp-downs faster than BESS, have longer useful life and are more economically profitable for smaller scale systems. A lab set-up is simulated in PSIM software, considering SCs as ESS in order to compare the LPF, the MA and the RRL and concluding that the RRL method presents the best performance for SCs as well.…”