Central Energy Storage System to Reduce the Harmful Effects of PV Systems under a High Penetration Scenario

Elso Rodríguez,Jaime Arau,Rene Osorio,Nimrod Vázquez,Fernando Medina,Claudia Hernández

doi:10.3390/electronics10192418

Abstract

Photovoltaic (PV) systems are used to generate electricity and they are considered less aggressive in their environmental impact. These systems require no further maintenance once they are installed, they do not pollute the environment and their average lifespan is high. These are the reasons why they are considered a good alternative for electricity generation. However, PV systems have different challenges to solve when they are connected to low voltage distribution grids and one of them is related to the power quality when there is a high penetration of PV systems, when voltage variations usually appear. In this paper, a central energy storage system (ESS) is considered to alleviate grid voltage variations under a high penetration scenario of PV systems instead of using multiples ESS. The proposal controls the energy injected into the grid to maintain the voltage variation within the standard, no limitations are imposed on the PV systems, and then as an advantage of the proposal, the PVs’ available energy is fully delivered to the grid. In addition, in the absence of sunlight the ESS may provide power to the grid. An analysis and experimental setup were built to validate the proposed scheme.

Highlights

Accepted: 26 September 2021Nowadays, the harmful effects on the environment from using fossil fuels for electricity generation are evident causing serious air and water pollution, and their overuse has been associated with global warming with severe consequences [1,2,3,4]
In the absence of PV systems, the levels of the supply voltages in the houses connected to the grid which are further away from the distribution transformer have significant drops, up to 4.5% of the nominal value of the grid voltage
When there is a massive connection of PV systems to the distribution lines there are voltage surges, especially in houses farther from the distribution transformer, up to 11%

Summary

Introduction

Accepted: 26 September 2021Nowadays, the harmful effects on the environment from using fossil fuels for electricity generation are evident causing serious air and water pollution, and their overuse has been associated with global warming with severe consequences [1,2,3,4]. Governments have been taking several actions to reduce the use of these fuels, including the development of new technologies for electricity generation, such as photovoltaic (PV) systems [5,6]. The large-scale use of PV systems and their massive connections to distribution systems can lead to several problems, different technologies to mitigate these effects have been developed [13]. They can be grouped into two categories depending on which aspect of the systems they are related to. The first category relates to the gridside control, which includes solutions such as using cables with a higher cross-section to reduce their impedance [14] and the use of on-line tap changers (OLTCs) [15]; these methods, despite being efficient, are expensive and require modifying the facilities

Results

Discussion

Conclusion