ENHANCING PV HOSTING CAPACITY USING SMART INVERTERS AND TIME OF USE TARIFFS

Abstract

The impacts of centralized and distributed PV on distribution network (DN) are extensively investigated in this thesis. Different weather conditions and different PV penetration levels are considered. Many aspects are examined such as voltage magnitude, voltage unbalance factor, performance of conventional voltage regulation devices, and energy losses. IEEE 123 node test feeder is modelled in this study and quasi-static time series daily simulations are performed using OpenDSS software. The impact of the centralized PV significantly appears close to its connection point and its surrounding area, while the impact of the distributed PV acts along the DN. It is observed that the more the PV penetration increases, the more the voltage magnitude and regulator tap changes increase. Moreover, the cloudy day will cause more voltage fluctuations and accordingly increase the tap change operation. It is also found that the distributed PV will have voltage unbalance factor more than the centralized PV. The PV hosting capacity is defined as the maximum PV that can be integrated into the DN without causing any violations to current and voltage constraints. A methodology for estimating the PV hosting capacity is proposed in this thesis. It considers the variability nature of the PV power output during the day. The PV smart inverter is used for mitigating the voltage issues at the PV point of common coupling. The Volt-Var function is used for mitigating the overvoltage, while the dynamic reactive current is used for mitigating the voltage fluctuations. In addition, time of use prices are used for decreasing the peak to valley difference for the utility net loads. Accordingly, the PV hosting capacity has been enhanced by using a combination of smart inverter and time of use electricity prices.