Operation of a Low Voltage Distribution Grid in Cyprus and the Impact of Photovoltaics and Electric Vehicles

Abstract

The operation of a typical 4-wire, radial, Low Voltage Distribution Grid (LVDG) in the Cyprus power system, where the neutral conductor is grounded only at the MV/LV transformer, is investigated under different scenarios. These include seasonal loading profiles and different penetration levels of photovoltaics (PVs) and electric vehicles (EVs). The analysis is focused on the impact of PVs and EVs on the voltage profile of the LVDG, the loading conditions of the distribution lines/cables and on the system losses. The results indicate that even with a moderate number of PVs, the admissible voltage limits can be exceeded due to the significant voltage drop across the neutral conductor. Moreover, the distribution lines/cables near the transformer can be overloaded if the charging process of the electric vehicles is not coordinated and is left freely to end users.

Voltage Regulation Under Unbalanced Power Flow in Active Four-Wire Low Voltage Distribution Grids

“…The settings and set points of these droop-based schemes are given in Fig. 5 while the active power generation profile in the numerical simulations corresponds to a sunny day during summer in Cyprus [2].…”

“…However, to achieve the target of net-zero emissions it is expected that the penetration of DERs, with mainly rooftop Photovoltaic (PV) systems, and electric vehicles (EVs) in LVDGs will increase further [1]. From a technical prospective, high penetrations of PV systems and EVs can introduce several challenges to the reliable operation of the distribution grid [2]. These include the increase of system losses, the thermal and voltage limits violations and the increase of system asymmetry.…”

Enhancing the State Estimation for Low Voltage Distribution Grids

“…Low voltage distribution grids have an integral role in the smart grid concept. The increasing energy demand, the electrification of the heating/cooling and transportation sectors as well as the need for a more sustainable future are pushing the contemporary distribution grids, and especially the LVDG, to their operational limits [1]- [2]. Under the framework of the smart grid, LVDGs are expected to completely transform from traditional passive grids into highly complex active systems.…”