دانلود رایگان مقاله تعیین اندازه ایستگاه های شارژ PHEV با سیستم PV شبکه تجاری

abstract

Due to low electricity rates at nighttime, home charging for electric vehicles (EVs) is conventionally favored. However, the recent tendency in support of daytime workplace charging that absorbs energy produced by solar photovoltaic (PV) panels appears to be the most promising solution to facilitating higher PV and EV penetration in the power grid. This paper studies optimal sizing of workplace charging stations considering probabilistic reactive power support for plug-in hybrid electric vehicles (PHEVs), which are powered by PV units in medium voltage (MV) commercial networks. In this study, analytical expressions are first presented to estimate the size of charging stations integrated with PV units with an objective of minimizing energy losses. These stations are capable of providing reactive power support to the main grid in addition to charging PHEVs while considering the probability of PV generation. The study is further extended to investigate the impact of time-varying voltage-dependent charging load models on PV penetration. The simulation results obtained on an 18-bus test distribution system show that various charging load models can produce dissimilar levels of PHEV and PV penetration. Particularly, the maximum energy loss and peak load reductions are achieved at 70.17% and 42.95% respectively for the mixed charging load model, where the system accommodates respective PHEV and PV penetration levels of 9.51% and 50%. The results of probabilistic voltage distributions are also thoroughly reported in the paper.

7. Conclusion

This paper has proposed a new analytical approach to determine the size of PHEV charging stations powered by various levels of commercial grid-connected PV penetration that considers probabilistic reactive power support for minimizing energy losses. The advantage of the proposed approach is that it can provide a quick estimation of the optimal size of PV-powered charging stations and their probabilistic reactive power support. These stations are capable of providing reactive power support to the grid in addition to charging PHEVs. The proposed approach has been further extended to study the impact of various time-varying voltagedependent commercial charging load levels on PV penetration. The results show that without charging stations, an 18-bus distribution feeder can accommodate a PV penetration level of 40%. With charging stations, a higher level of 55% and 15.35% for respective PV and PHEVs can be achieved when the normal charging load model is adopted. However, due to a mismatch between the charging demand and PV generation, the fast charging load model cannot enable higher PV penetration while adopting a rather low amount of PHEVs, at 3.52%. Moreover, a practical or mixed load charging model that is defined as a mix of the fast and normal models has been examined. For this model, the penetration levels of respective PV and PHEVs are 50% and 9.50%, and the largest reductions in the energy loss and peak active load are estimated at 70.17% and 42.95%, respectively. The simulation results also confirm that optimal sizing and operation of PV-powered charging stations with reactive power support, which is fully compliant with a recently published amendment to the standard IEEE 1547, can lead to a significantly lower energy loss, higher levels of PV and PHEV penetration and a higher peak load reduction than the scenario without consideration of reactive power support. Accordingly, the proposed approach could be a useful study tool to support daytime workplace charging that absorbs energy produced by solar PV panels and to facilitate higher penetration levels of PV and PHEVs in distribution networks.