Voltage fluctuation smoothing in distribution systems with RES considering degradation and charging plan of EV batteries

Abstract

Recently, the use of renewable energy sources (RES) and electric vehicles (EVs) has been rapidly increased worldwide. As a result of the highly fluctuating nature of RES, the charging and discharging rates of EVs significantly have to be increased, and so the lifespan of EV batteries decreases. In this paper, an optimization-based method is proposed to smooth voltage fluctuations due to various RES types by optimally controlling the charging and discharging power of EVs and the reactive power of the RES inverters. To extend the lifespan of the EV battery, EV power fluctuations and their minimum preset state of charge (SOC) are considered in the proposed optimization model. For this purpose, a new multi-objective function is formulated, including 1) voltage fluctuations, 2) EV power fluctuations, and 3) the deviation of SOC of EVs from their minimum desired level. The use of the hull moving average (HMA) is proposed to mitigate voltage fluctuations, which eliminates the lag problem of the widely used moving average methods. The gravitational search algorithm (GSA) is utilized to accurately solve the optimization model. The simulation results demonstrate the effectiveness of the proposed method to smooth voltage fluctuations while considering degradation and charging plan of EV batteries.

Tie-line Power Flow Control Method for Grid-connected Microgrids with SMES Based on Optimization and Fuzzy Logic

“…Tables IV and V illustrate the validation and robustness of the proposed methods in terms of the deviation of the duty cycle and the deviation of the voltage of DC-link capacitor. The deviation of the duty cycle of chopper circuit DDC can be calculated according to (23), and the deviation of the voltage of DC-link capacitor VD can be calculated according to (24).…”

“…Due to the intermittent nature of PV power generation and unexpected load variations, the line power at PCC is dramatically changing accordingly [22], [23]. This power transfers between the utility power grid and the PV solar station and it can be negative (i.e., the power goes to the grid) or positive (i.e., the power outgoes from the grid).…”

A Short-Term Preventive Maintenance Scheduling Method for Distribution Networks With Distributed Generators and Batteries

“…In preventive maintenance, the degradation conditions of the components can be evaluated based on different standards. For example, [21] analyzed the influence of factors such as power fluctuation, states of charge, and the charging/discharging rates on the life spans of the electric vehicle batteries. According to the factors, a charging plan was proposed to enlarge the life spans of electric vehicle batteries.…”

En route of electric vehicles with the vehicle to grid technique in distribution networks: Status and technological review

“…Moreover, proper load supervision can avoid phase imbalance issues. A gravitational search algorithm is proposed in Reference to smooth voltage fluctuations by using Hull moving average due to renewable sources to optimally control the charging and discharging power of EVs and the reactive power of the RES inverters. To optimize the active and reactive power of the PV converter the authors in Reference have used the sensitivity and optimization tuned algorithm from the charging station for matching a target voltage profile.…”