Calculating Operational Patterns for Electric Vehicle Charging on a Real Distribution Network Based on Renewables’ Production

Abstract

The connection of electric vehicles to distribution networks has been an emerging issue of paramount importance for power systems. On one hand, it provides new opportunities for climate change mitigation, if electric energy used for charging is produced from zero emission sources. On the other hand, it stresses networks that are now required to accommodate, in addition to the loads and production from distributed generation they are initially designed for, loads from electric vehicles charging. In order to achieve maximum use of the grid without substantially affecting its performance, these issues have to be addressed in a coordinated manner, which requires adequate knowledge of the system under consideration. It is advantageous that electric vehicle charging can be controlled to a certain degree. This research provides better understanding of real distribution networks' operation, proposing specific operational points through minimizing electric vehicle charging effects. The probabilistic Monte Carlo method on high performance computers is used for the calculations.Energies 2018, 11, 2400 2 of 15 However, stochastic methods, and especially Monte Carlo [11], is computationally demanding even for today's standards; hence, specific operational points are developed in this study for a specific network [12].Electric vehicles charging would also require a grid expansion design factor [13]. Current research on electric vehicles, as far as the distribution network is concerned, gives emphasis to probabilistic methods in order to predict charging patterns, and predict the expected charging behavior. This also affects the connection points for distributed generations, that could be optimally different if connected points are based on probabilistic methods, taking into consideration their intermittency [14]. As far as electric vehicles are concerned, the first step is to characterize their charging demand [15]. In some cases, the system is simulated as a whole, and the operational benefits are optimized based on electric charging owners' behavior [16]. Alternatively, they are connected in a way that relieves distribution system constraints [17]. Active distribution network management could be done by aggregating electric vehicle behavior in a probabilistic manner [12]. Probabilistic studies have also shown good correlation between electric vehicles and renewables [18]. In this research, electric vehicle and load aggregation is performed on the level of a secondary distribution system, at the point of medium voltage (MV)/low voltage (LV) connection, and it is fully controlled.Having mentioned the above, several studies have researched the emerging phenomenon of electric vehicles. All of them are consumer oriented, giving emphasis to electric vehicles per se, and showing minimal consideration for the electricity grid. On the other hand, the research presented in the current paper is electric grid oriented. It is focused in the procedure of creating optimal electric grid operation points for electric vehicle charging for a r...

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