Article Preview
TopI. Introduction
With the increase in energy demand in developing countries and environmental issues, non-conventional energy sources are being prioritized as the best choice for meeting energy demand in terms of both economic and environmental considerations. Solar energy is available in abundance which can be used to encounter the energy demand and reduce the dependence on conventional fossil fuels. This solar energy can be utilised at a small scale i.e. in form of distributed generations (DGs) in the distribution system by converting it into electrical energy using a photovoltaic system. Distributed generation systems can also be grid-connected or stand-alone. Recently, there has been an immense increase in the adoption of non-conventional energy based distributed generations in power systems. There is the expectation of increase in this penetration level in the future, as these DG systems have important roles in pollution reduction, reduction in power transfer losses, and maximizing the utilisation of local renewable energy sources. However, the intensively growing adoption of distributed generation units raises significant problems like power quality concerns, reverse power transfer, voltage variation and frequency deviation in the power network (Paál & Tatai, 2010)(Coster et al., 2011). The conventional grid-connected inverters are configured to yield active power only. However, electrical loads are mainly inductive and with an increase in load, more reactive power is required which is supplied by the grid only, resulting in a decrease in voltage and a low power factor from the utility's viewpoint, negatively impacting power system's overall efficiency. Conventionally the reactive power is compensated by proper utilisation of capacitor banks, FACTS devices, and tap changing transformer. Studies conducted in (de Oliveira Quevedo et al., 2016)(Sarimuthu et al., 2016)(Bangash et al., 2015)(Han et al., 2015) proposed transformer tap changers for voltage control. voltage control by utilising capacitor banks (CB) was suggested in (Kayal & Chanda, 2016)(De Araujo et al., 2018)(Mohsin et al., 2016)(Nezhad & Bevrani, 2017)(Doostan et al., 2016)(Onaka et al., 2017).
The voltage control methods using STATCOM is addressed in (Luo et al., 2018)(Lu et al., 2017)(Hashempour & Lee, 2017)(Saha et al., 2017)(Chai et al., 2021)(Tien et al., 2017). These traditional devices have certain disadvantages like large size, high installing costs, a huge area required for installation etc.
The grid-connected solar inverter can deliver both reactive and active power. By utilizing the reactive power capability of solar inverter, the reactive power demand can be reduced. This work provides a brief perspective on the solar power utilisation and reactive power capability of solar inverter.