A Study on Compensating Voltage Drop in Distribution Systems due to Nighttime Simultaneous Charging of Electric Vehicles Utilizing Charging Power Adjustment and Reactive Power Injection

摘要

To reduce the environment load, electric vehicles (EV) have been attracting attention and expectations. Since they can run with at good fuel efficiency and without exhaust gases. It is expected that EV will become more and more popular. Generally, EVs would be used for driving during daytime and be charged during the nighttime, considering lifestyle and time-of-use patterns. If most EV owners adopt this use pattern, feeder voltage profiles could be greatly affected, causing severe voltage drops. The battery charger for EVs described in this papers consists of a self-commutated inverter, which in principle can control not only active power but also reactive power. We propose a basic feeder voltage regulation algorithm, "PQ control", using EVs which involves adjustment of the EV charging schedule and reactive power injection. In addition, we propose "prediction control", which is based on "PQ control" and is takes account of prediction of the receiving voltage. Advanced "communication control" regulation algorithms, utilizing communication among EVs and the distribution system operator, are also proposed. The purpose of this paper is to confirm the effectiveness of the three proposed algorithms by simulations.