Impact of High Penetration of Electric Vehicles on Low Voltage Network Stability and Role of Managment Programmes for Electric Vehicle Charging
Abstract
The number of electric vehicles (EVs) have increased in Norway over the last couple of
years. Low emissions and reducing petroleum dependence are some of the advantages
achieved by using EVs. This master thesis presents the impact of high penetration of EVs on
a low voltage distribution network. Uncontrolled charging patterns of EVs will likely stress the
distribution network and could cause power outages, voltage fluctuations, thermal stress on
the lines and harmonic pollution. As an alternative to grid reinforcement, smart load
management (SLM) and demand side management (DSM) were introduced for coordinating
the charging of large numbers of EVs.
Simulations of uncoordinated and coordinated charging of EVs were conducted with the
power grid calculation software DIgSILENT PowerFactory and the proposed management
algorithms written in MATLAB. The network was simulated using none, two and eight EVs
connected. The Nissan Leaf battery specifications were used as a reference, where 3,3 kW
and 6,6 kW charging power were tested. The impact of the original scheduled EV loads were
compared with the results from applying the management programmes to the system, and
discussed with respect to network stability and user satisfaction.
The transformer was the main bottleneck for the system, but also overloading of overhead
lines limited the charging of the EVs. Of the programmes tested, the minute-based SLM
programme gave the best results. The constraints were adhered, and the delay of the
charging was reasonable. Increased charging power was also possible for this programme
during the most power demanding periods with similar results.
Description
Masteroppgave fornybar energi- Universitetet i Agder, 2015