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电动汽车(EV)充电会对配电网产生影响,其充电成本取决于充电时的电价。为了最大程度地降低成本,一个负责大EV集群的集中器可采用基于市场的控制算法来协调车辆充电。在这一优化中,不考虑连接EV的配电网的运行参数。这可能会导致不符合电网技术限制条件的情况出现(如电压偏低、相位不平衡);例如,当电价较低时大量汽车开始同时充电。同时考虑经济方面和技术方面的多目标优化是比较复杂的,因为该优化必须将市场层面的时间驱动型控制与运行层面的事件驱动型控制结合起来。不同的案例研究调查了在何种情况下协调EV充电的基于市场的控制会与配电网的运行限制条件发生冲突。尤其是在弱电网中,相位的不平衡和电压问题会随着EV的高份额而出现。如果局部电压较低,在EV的充电位置可以采用低水平电压下垂控制器,通过降低充电功率来满足电网的运行限制条件。虽然这一操作意味着会偏离成本最优运行点,但结果表明该方法对集中器工作状况的影响是非常有限的,即使是在承载大量EV的弱配电网中,也能够满足配电网技术的限制条件。
Electric vehicle (EV) charging will have an impact on the distribution network, the charging cost depends on the price of electricity at the time of charging. In order to minimize costs, a concentrator responsible for large EV clusters can employ market-based control algorithms to coordinate vehicle charging. In this optimization, the operating parameters of the distribution network connected to the EV are not considered. This may result in conditions that do not qualify as grid technologies (eg low voltage, unbalanced phase); for example, a large number of cars start charging at low prices. It is complicated to consider both economic and technical aspects of multi-objective optimization because the optimization must combine time-driven control at the market level with event-driven control at the operational level. Different case studies investigated under what conditions market-based controls that coordinate EV charging conflict with the operating constraints of the distribution network. Especially in weak grids, phase imbalances and voltage problems occur with a high share of EVs. If the local voltage is low, a low-level voltage droop controller can be used at the charging location of the EV to meet the grid operating constraints by reducing the charging power. Although this operation means deviating from the cost optimal operation point, the results show that this method has a very limited impact on the working condition of the concentrator. Even in a weak distribution network carrying a large amount of EV, it can also meet the requirements of the distribution network Technical restrictions.