*1.4. Paper Contribution and Organization*

Generally, the literature defines the impact of EV stations' integration into the grid; however, most of the above-mentioned impact studies were performed at a unity power factor. Nowadays, grid-tie inverters can regulate their power factor by shifting their output voltage phase angle to supply or draw reactive power [19]. Another concern is that the increased demand for renewable energy sources (RESs) may have a negative effect on the distribution network [17], and enhancement techniques such as reactive power compensation will be considered alongside other factors while sizing for RES capacity [26]. According to a survey of the literature, most of the research concentrates predominantly on the impact of EV alone on power quality or with renewable energy sources, with less focus on the combined managed impact of EV with PV systems on the grid with reactive power control at non-unity operation.

This paper proposes analyzing the impact of EV integration on the distribution network by considering PV generation with reactive power compensation. This study suggests sizing the PV holding capacity based on enhancement techniques, such as system power loss minimizing. This capacity is based on considering the inverter size compared to the PV size, which is referred to as the inverter-to-PV ratio throughout this paper.

The summary of the proposed work is as follows: The maximum EV penetration for the distribution network is obtained for different scenarios. Subsequently, the optimal integration of solar PV with charging stations is obtained based on reactive power consideration and the inverter-to-PV ratio (power factor). The impact of the EV penetration level on the distribution system's constraints is analyzed. The effect of reactive power generation on the grid on the impact study is considered. A forward/backward load flow model is used based on daily load profiles. Finally, modeling and simulation of a real-life residential area case study in Kuwait (Ahmadi) is carried out to obtain actual results.

The paper is structured as follows: In Section 2, the proposed approach for assessing the electric vehicle's impact is explained; this section defines how to obtain EV charging demand, the PV capacity with its effect on the EV charging station, and the reactive power consideration from the PV inverter. Section 3 presents the models for the distribution network, the system load model, and the load flow problem. In Section 4, the case study explains the location of the test area, and the assumptions, considerations, and load profiles are defined. The results are presented and discussed in Section 5; this section considers the EVCS demand for an IEEE 33 bus, the EVCS demand of the Ahmadi residential area, the effect of PV inverter penetration on line losses with reactive power control, the effect of PV inverter power factors on PV optimum size, and a daily assessment of the power system for the Ahmadi distribution network with PV generation and EVCSs. The paper ends with a final summary of the findings and the conclusion in Section 6.

## **2. Proposed Approach for Assessing EV Impact**

In this paper, different scenarios are considered to analyze the impact on the demands of EVCSs on the electric grid. The proposed approach considers EVCS to be the main load connected to the power system, rather than considering individual EVs as loads. Load flows are run to study the performance of distribution networks to assess certain performance and impact indices, such as nodal voltage variation and feeder overloading [26]. An approach for optimal PV integration is based on obtaining the optimal inverter size for power loss minimizing, considering the reactive power control capacity of the PV inverter. This method is based on the enhancement technique sizing of renewable sources in [15]. Finally, the effectiveness of this approach is assessed by analyzing the EVCS impact study combined with PV and reactive power control.

### *2.1. EV Charging Demand*

The installation of EVCSs requires power system adequacy assessments. The concept of extra effective available energy determines the number of EV loads that can be connected to the system without infrastructure expansion [27]. The same concept was applied in this study to obtain the EVCSs' maximum demand. The capacity of the chargers was obtained by load flow simulation, as explained in Figure 1a.

**Figure 1.** Flow chart for (**a**) electric vehicle charging stations (EVCSs)' maximum demand. (**b**) Maximum PV penetration. PV, photovoltaic; PF, power factor.

The load flow iteration obtains the maximum demand of EVCSs that can be added to the existing distribution system. The power system's physical boundaries impose constraints on the voltage magnitudes (*V*min <sup>=</sup> 0.95 *<sup>p</sup>*.*u*., *<sup>V</sup>*max <sup>=</sup> 1.05 *<sup>p</sup>*.*u*.) and phase angles (δmin <sup>=</sup> <sup>−</sup>30<sup>o</sup> and <sup>δ</sup>max = +30o) for all bus voltages in the power network.

$$V\_{\rm min} \le V\_i \le V\_{\rm max} \tag{1}$$

$$
\delta\_{\rm min} \le \delta\_{\rm l} \le \delta\_{\rm max} \tag{2}
$$

The currents in the power lines must not exceed the rated value (1 p.u.), as in Equation (3).

$$I\_{Iice} \le I\_{Rated} \tag{3}$$

To obtain the maximum demand for EVCSs, the power system is studied for worst-case scenarios when the loading is during peak hours. The actual maximum load demand for the case study was considered in the load flow.
